阅读说明：本技术 半导体封装 (Semiconductor package ) 是由 郑礼辉 高金福 卢思维 潘志坚 于 2020-02-14 设计创作，主要内容包括：公开半导体封装及其形成方法。一种半导体封装包括管芯及底部填充胶。管芯设置在表面之上且包括第一侧壁。底部填充胶包封管芯。底部填充胶包括位于第一侧壁上的第一底部填充胶部分,且在剖视图中,第一底部填充胶部分的第二侧壁具有转折点。(Semiconductor packages and methods of forming the same are disclosed. A semiconductor package includes a die and an underfill. The die is disposed over the surface and includes a first sidewall. The underfill encapsulates the die. The underfill includes a first underfill portion on the first sidewall, and in cross-section, a second sidewall of the first underfill portion has a hinge point.)

1. A semiconductor package, comprising:

a die located over the surface and including a first sidewall; and

an underfill encapsulant encapsulating the die, the underfill including a first underfill portion on the first sidewall, wherein in a cross-sectional view, a second sidewall of the first underfill portion has a hinge point.

Technical Field

Embodiments of the present invention relate to a semiconductor package.

Background

Semiconductor devices and Integrated Circuits (ICs) used in various electronic devices, such as cell phones and other mobile electronic devices, are typically fabricated on a single semiconductor wafer. The dies of a wafer can be processed and wafer-level packaged with other semiconductor devices or dies, and various techniques have been developed for wafer-level packaging. How to ensure the reliability of wafer level packages has become a challenge in the art.

Disclosure of Invention

A semiconductor package of an embodiment of the invention includes a die and an underfill. The die is disposed over the surface and includes a first sidewall. The underfill encapsulates the die. The underfill includes a first underfill portion on the first sidewall, and in cross-section, a second sidewall of the first underfill portion has a hinge point.

A semiconductor package of an embodiment of the invention includes a first die and an underfill. The first die is bonded to the surface and includes a first sidewall. An underfill encapsulates the first die and partially exposes the first sidewalls. The underfill includes a first underfill portion on the first sidewall. The first underfill portion includes a second sidewall. The width between the first sidewall and the second sidewall decreases or remains substantially the same as the first underfill portion becomes closer to the surface.

A method of manufacturing a semiconductor package of an embodiment of the present invention includes the following steps. A plurality of conductive features are formed alongside the first die. A temporary underfill termination is continuously formed along at least one side of the first die between the first die and portions of the plurality of conductive features. An underfill paste is filled between the first die and the temporary underfill termination. The temporary underfill stop is removed.

Drawings

Fig. 1A-1J are schematic cross-sectional views of various stages of fabricating a semiconductor package, according to some embodiments.

Fig. 2A is a schematic top view of fig. 1D.

Fig. 2B is a schematic top view of fig. 1E.

Fig. 3A-3F are schematic cross-sectional views of various stages of fabricating a semiconductor package, according to some embodiments.

Fig. 4A-4D are schematic cross-sectional views of various stages of fabricating a semiconductor package, according to some embodiments.

Fig. 5A-5F are schematic cross-sectional views of various stages of fabricating a semiconductor package, according to some embodiments.

Fig. 6A is a schematic top view of fig. 5B.

Fig. 6B is a schematic top view of fig. 5C.

Fig. 7 is a schematic cross-sectional view of a semiconductor package according to some embodiments.

Fig. 8 is a schematic cross-sectional view of a semiconductor package according to some embodiments.

Detailed Description

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. For the purpose of conveying the disclosure in a simplified manner, specific examples of components and arrangements are set forth below. Of course, these are merely examples and are not intended to be limiting. For example, forming a second feature "over" or "on" a first feature in the description that follows may include embodiments in which the second feature is formed in direct contact with the first feature, and may also include embodiments in which additional features may be formed between the second and first features, such that the second feature may not be in direct contact with the first feature. Moreover, in various examples of the disclosure, the same reference numbers and/or letters may be used to refer to the same or similar components. The repetition of reference numbers is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Furthermore, spatially relative terms such as "under", "lower", "on" at … "," over … "," over "," upper ", and the like may be used herein to facilitate describing one element or feature's relationship to another (other) element or feature as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly as well.

Fig. 1A-1J are schematic cross-sectional views of various stages of fabricating a semiconductor package, according to some embodiments.

Referring to fig. 1A, a plurality of semiconductor dies is disposed on a temporary carrier C. For example, after a singulation process is performed to separate individual semiconductor dies from a semiconductor wafer (not shown), the dies 110, 120 are picked and placed on a temporary carrier C. The temporary carrier C may be a glass carrier, a ceramic carrier, a metal carrier, or the like. After the dies 110, 120 are placed side by side on the temporary carrier C, a gap is formed between the dies 110, 120. In some embodiments, the dies 110, 120 are attached to the temporary carrier C by an adhesive layer AD. The adhesive layer AD may be a Die Attach Film (DAF) or other suitable adhesive material. In some embodiments, a release layer (de-bonding layer) DB is further formed between the temporary carrier C and the adhesive layer AD. In some embodiments, the release layer DB is formed of an adhesive such as an Ultraviolet (UV) glue, a Light-to-Heat Conversion (LTHC) glue, or other types of adhesives. In some embodiments, the release layer DB may be decomposed under heat of light to release the temporary carrier C from the overlying structure to be formed in a subsequent step. In some alternative embodiments, a buffer layer may be formed between the peeling layer DB and the temporary carrier C. The buffer layer may include a dielectric material layer made of a dielectric material including benzocyclobutene (BCB), Polybenzoxazole (PBO), or any other suitable polymer-based dielectric material.

The die 110 may include a semiconductor substrate 112, conductive connections 114 distributed over the semiconductor substrate 112, and a protective layer 116 disposed on the semiconductor substrate 112 and surrounding the conductive connections 114 for protection. In some embodiments, die 120 includes a similar or identical structure as die 110. For example, the die 120 includes a semiconductor substrate 122, conductive connections 124 distributed over the semiconductor substrate 122, and a protective layer 126 disposed on the semiconductor substrate 122 and surrounding the conductive connections 124 for protection. In some embodiments, the conductive connections 114/124 include conductive pillars, vias, bumps, and/or posts (post) made of solder, gold, copper, or any other suitable conductive material. The conductive connection 114/124 may be formed by an electroplating process or other suitable deposition process. The surface on which the conductive connections 114 are distributed may be referred to as a front surface 110a (e.g., an active surface) of the die 110 for further electrical connections. Similarly, the surface on which the conductive connections 124 are distributed may be referred to as a front surface 120a (e.g., an active surface) of the die 120 for further electrical connections. The front surface 120a of the die 120 faces in the same direction as the front surface 110a of the die 110. In some embodiments, the material of protective layer 116/126 includes polybenzoxazole, polyimide, suitable organic or inorganic materials, and the like.

The dies 110, 120 may be the same type of semiconductor die or different types of semiconductor die. In some embodiments, die 110 and/or die 120 may include active components (e.g., transistors, etc.) and (optionally) passive components (e.g., resistors, capacitors, inductors, etc.) formed on semiconductor substrate 112/122. Die 110 and/or die 120 may be logic dies, such as a Central Processing Unit (CPU) die, a Graphics Processing Unit (GPU) die, a Micro Control Unit (MCU) die, an input-output (I/O) die, a baseband (BB) die, or an Application Processor (AP) die. In some embodiments, at least one of the dies 110, 120 may be a memory die, such as a High Bandwidth Memory (HBM) die. In some embodiments, at least one of the dies 110, 120 may be a System-on-Die (SoC) Die or a Die stack. It should be understood that the number of dies to be packaged and the functionality of the dies may depend on design requirements.

Referring to fig. 1A, an encapsulant 130 is formed over the temporary carrier C to encapsulate the dies 110, 120. The encapsulant 130 includes a mold compound (e.g., epoxy), a dielectric material (e.g., polybenzoxazole, polyimide, benzocyclobutene, combinations thereof), or other suitable electrically insulating material. In some embodiments, the method of forming the encapsulant 130 includes at least the following steps. An insulating material (not shown) is formed over the temporary carrier C such that the dies 110, 120 are overmolded and the gap between the dies 110, 120 is filled. Next, a thinning process is performed on the insulating material to reduce the thickness of the insulating material until at least a portion of the conductive connections 114 of the die 110 and at least a portion of the conductive connections 124 of the die 120 are visibly revealed. The thinning process may include a grinding process, a Chemical Mechanical Polishing (CMP) process, and/or a planarization process or other suitable removal process. Optionally, a cleaning step is performed after the thinning to clean and remove residues generated from the thinning process. After reducing the thickness of the insulating material, the encapsulant 130 is formed. However, the formation of the encapsulant 130 may be performed by any other suitable technique, and the disclosure is not intended to be limited by the above description. In some embodiments, protective layer 116 and/or conductive connections 114 of die 110 and protective layer 126 and/or conductive connections 124 of die 120 may be slightly removed and planarized during the thinning process. Conductive connectors 114 of die 110 and conductive connectors 124 of die 120 may be exposed in an accessible manner by protective layer 116 and protective layer 126, respectively. The protective layer 116 of the die 110 may cover the conductive connections 114 at least laterally. Similarly, the protective layer 126 of the die 120 may cover the conductive connections 124 at least laterally. In some embodiments, after forming the encapsulant 130, the surface 130a of the encapsulant 130 may be substantially coplanar with the front surface 110a of the die 110 and the front surface 120a of the die 120.

Referring to fig. 1B, a re-routing structure 140 is formed on the surface 130a of the encapsulant 130, the front surface 110a of the die 110, and the front surface 120a of the die 120. The redistribution structure 140 includes, for example, a patterned dielectric layer 142 and a patterned conductive layer 144 in the patterned dielectric layer 142. In some embodiments, the method of forming the redistribution structure 140 includes at least the following steps. A dielectric material (e.g., polybenzoxazole, polyimide, benzocyclobutene, or other suitable electrically insulating material) is formed over surface 130a of encapsulant 130, front surface 110a of die 110, and front surface 120a of die 120 using a spin-on process, a deposition process, or other suitable process. Next, portions of the dielectric material are removed by photolithography and etching or other suitable removal processes to form a patterned dielectric layer 142 having a plurality of openings. The openings of patterned dielectric layer 142 expose at least portions of conductive connections 114 of die 110 and at least portions of conductive connections 124 of die 120. Subsequently, a conductive material (e.g., a metal or metal alloy such as copper, silver, gold, tungsten, cobalt, aluminum, or alloys thereof) is formed over the surface of the patterned dielectric layer 142 and also inside the openings of the patterned dielectric layer 142. The conductive material is then patterned by patterning and metallization techniques (e.g., seed layer deposition, photolithography, plating, etching, etc.) to form a patterned conductive layer 144. Other suitable techniques may be utilized to form the rerouting structure 140. The patterned conductive layer 144 may include conductive lines, vias, conductive pads, and the like. The patterned conductive layer 144 may penetrate the patterned dielectric layer 142 to make physical and electrical contact with the conductive connections 114 of the die 110 and the conductive connections 124 of the die 120. It is understood that the number of patterned dielectric layers and patterned conductive layers may depend on the circuit design and is not limited by the embodiments.

It should be noted that although one patterned dielectric layer 142 and one patterned conductive layer 144 are shown in fig. 1B, the number of these layers is not limited in the present disclosure. In some alternative embodiments, the redistribution structure 140 may be composed of more patterned dielectric layers 142 and patterned conductive layers 144, depending on the design.

Referring to fig. 1C, a plurality of conductive features CF are formed on the surface 140a of the rewiring structure 140. In some embodiments, the conductive feature CF is formed on the top surface of the patterned conductive layer 144 of the re-wiring structure 140 to be electrically connected to the patterned conductive layer 144. In some embodiments, the conductive features CF may be referred to as conductive pillars. The material of the conductive features CF includes copper, nickel, solder, combinations thereof, and the like. In some embodiments, the method of forming the conductive feature CF includes the following steps. A photoresist layer having an opening (not shown) is formed on the redistribution structure 140, and the opening of the photoresist layer may expose a desired position of the patterned conductive layer 144 for a subsequently formed conductive feature CF. Subsequently, a plating process or other suitable deposition process is performed to form a metal layer (e.g., a copper-containing layer) in the openings of the photoresist layer, and then the photoresist layer is removed. The conductive feature CF remains on the patterned conductive layer 144 of the rewiring structure 140. The conductive features CF may be electrically coupled to the dies 110, 120 through the rewiring structure 140. It is understood that the number and location of the conductive features CF is variable and may be modified based on design requirements.

Referring to fig. 1C, a die 150 is disposed on the surface 140a of the rerouting structure 140. For example, after the conductive features CF are formed, the die 150 is picked and placed on the rerouting structure 140. In some embodiments, the die 150 is surrounded by a conductive feature CF. The distance D between the die 150 and the conductive feature CF may be substantially equal to the distance between the die 150 and the conductive pattern of the patterned conductive layer 144 underlying the conductive feature CF. For example, the distance D is in the range of 5 μm (micrometers) to 2000 μm. In some embodiments, the conductive features CF are formed prior to placement of the die 150. However, the present disclosure is not limited thereto. In some alternative embodiments, the die 150 may be placed prior to forming the conductive features CF on the rerouting structure 140.

Die 150 may be the same type or a different type of semiconductor die relative to die 110 or die 120. In some embodiments, die 150 includes a semiconductor substrate 152, a device layer 154 disposed on semiconductor substrate 152, and a conductive connection 156 connected to device layer 154. In some embodiments, die 150 includes Through Semiconductor Via (TSV) 158. TSV158 penetrates semiconductor substrate 152 so as to make electrical contact to device layer 154. Device layer 154 may include a variety of IC devices formed on semiconductor substrate 152. The surface on which the conductive connections 156 are distributed may be referred to as a front surface 150a (e.g., an active surface) of the die 150. In some embodiments, die 150 is a bridge die (e.g., a silicon bridge die) for providing a short electrical connection path between dies 110, 120. In some embodiments, die 150 includes interconnect structures and no active and/or passive devices. In some alternative embodiments, die 150 includes interconnect structures, active devices, and (optionally) passive devices.

Die 150 may be flip-chip die disposed. For example, after the die 150 is disposed, the front surface 150a of the die 150 is connected to the patterned conductive layer 144 by a plurality of solder connections 159, and the front surface 150a of the die 150 faces the front surface 110a of the die 110 and the front surface 120a of the die 120. In some embodiments, a solder paste (not shown) may be formed on the conductive connection 156. Subsequently, the conductive connection member 156 having the solder paste formed thereon is attached to the uppermost portion of the patterned conductive layer 144. Thereafter, a reflow process is performed to ensure adhesion between the die 150 and the re-routing structure 140, thereby forming solder connections 159 between the spaces from the conductive connections 156 and the uppermost portion of the patterned conductive layer 144. After die 150 is bonded to patterned conductive layer 144, die 110 and die 120 are electrically connected by die 150 through patterned conductive layer 144, solder connections 159, conductive connections 156, and device layer 154.

Referring to fig. 1D and fig. 2A, which is a top view of fig. 1D, a temporary underfill termination 160 is formed on the rewiring structure 140 between the die 150 and the conductive features CF. A temporary underfill termination 160 is formed continuously along at least one side of the die 150. In some embodiments, the temporary underfill terminator 160 is formed on the surface 140a of the patterned dielectric layer 142 without contacting the patterned conductive layer 144. A temporary underfill termination 160 is disposed between the conductive feature CF and the die 150 and is separate from the conductive feature CF and the die 150. The temporary underfill termination 160 does not contact the conductive features CF and the die 150. The material of the temporary underfill terminator 160 includes Ultraviolet (UV) curable polymers such as acrylic and epoxy based materials. The temporary underfill terminator 160 may have a thermal resistance in the range of 100 ℃ to 200 ℃. In some embodiments, the method of forming the temporary underfill termination 160 includes the following steps. A UV curable material is dispensed by an inkjet printer on the surface 140a of the patterned dielectric layer 142 between the die 150 and the conductive features CF. Specifically, the UV curable material is dispensed along a box-shaped path (not shown) that surrounds the area occupied by the die 150. Next, a curing process is performed on the UV curable material by providing light having a UV wavelength or other suitable heating method. In other words, the temporary underfill terminator 160 may be formed by dispensing a UV curable material and curing the dispensed UV curable material. In some embodiments, the curing process may be performed on the UV curable material at a temperature between about 50 ℃ and 250 ℃ for a time period ranging between 10 minutes and 4 hours. However, any suitable temperature and duration may be employed in the curing step. In addition, the energy for dispensing and the temperature of the curing process may be adjusted to form a temporary underfill termination 160 having a desired cross-sectional shape, height H, width W, and the like.

As shown in fig. 2A, the temporary underfill terminator 160 includes a box-shaped structure in a top view. The box-like structure is continuously disposed around die 150 to surround die 150. In some embodiments, the inner and outer sidewalls of the temporary underfill termination 160 are each substantially parallel to the sidewalls 150s of the die 150. Thus, the width W of the temporary underfill terminator 160 is substantially constant. In some embodiments, the width W of the temporary underfill termination 160 may be in the range of 50 μm to 1000 μm. As shown in fig. 1D, the cross-sectional shape of the temporary underfill termination 160 may be, for example, a pillar with a curved top surface. The height H of the temporary underfill terminator 160 is less than the height of the die 150. In some embodiments, the height H may be in the range of 10 μm to 1000 μm. Although the temporary underfill terminator 160 shown in fig. 1D has a pillar shape, the shape of the temporary underfill terminator is not limited in this disclosure.

Referring to fig. 1E and fig. 2B, which is a top view of fig. 1E, after forming the temporary underfill terminator 160, an underfill 170 is formed between the temporary underfill terminator 160, the die 150, and the redistribution structure 140. In some embodiments, the material (e.g., an epoxy mixture) of the underfill 170 is initially dispensed into the gap between the temporary underfill termination 160 and the die 150 using an underfill dispensing device (not shown). For example, the material of the underfill 170 is dispensed along only one or two adjacent sides of the die 150 by a one-sided or two-sided dispensing process. The material of the underfill 170 may include a polymer (e.g., epoxy, polyimide, polyamine, polynitrile, polyacrylate, oxazole polymer, etc.). The material of the underfill 170 may include a filler material (e.g., oxide, nitride, carbide, etc.) in addition to a polymer. The material of the underfill 170 then flows between the die 150 and the redistribution structure 140 and fills the gaps between the temporary underfill termination 160, the die 150, and the redistribution structure 140 by capillary action. Subsequently, a curing process is performed to harden the material of the underfill 170, thereby forming the underfill 170. During the dispensing step of the underfill material, the temporary underfill finish 160, having a sufficient height H, acts as a barrier (barrier) to retain the material of the underfill 170 within the area surrounded by the temporary underfill finish 160. Thus, the underfill 170 is prevented from touching and bleeding out to the conductive features CF. Accordingly, cracking (crack) and disconnection (break connection) of the conductive features CF may be prevented during the subsequent thermal process. In addition, the underfill 170 may cover (or laterally surround) the conductive connections 156, the solder connections 159 of the die 150, and the patterned conductive layer 144 of the redistribution structure 140, thereby strengthening the connections therebetween and preventing thermal stress from breaking the connections therebetween.

Referring to fig. 1F, after the underfill 170 is formed, the temporary underfill stopper 160 is removed. In some embodiments, the temporary underfill terminator 160 may be removed by a wet or dry cleaning process or other suitable removal process. The wet cleaning process may be performed using a cleaning agent such as water, tetramethylammonium hydroxide (TMAH), and OH-based solution, and the dry cleaning process may be performed using O₂System plasma, Ar system plasma, CF₄Is plasma, N₂Plasma, combinations thereof, and the like.

During formation, portions of the underfill 170 are in contact with the temporary underfill stop 160, and thus the shape of the underfill 170 may be defined in part by the temporary underfill stop 160. In some embodiments, when the temporary underfill stop 160 has a post shape, the underfill 170 may have a geometric shape in which the sidewall 174 of one side of the underfill 170 has two different connecting sidewalls 174 when viewed from a cross-sectional view of the underfill 170The turning point TP of the portion. In an embodiment, the above geometry may be referred to as a house-like shape. The underfill 170 encapsulates portions of the sidewalls 150s of the die 150 and partially exposes the sidewalls 150s of the die 150 (i.e., the top portions of the sidewalls 150 s). In some embodiments, the underfill 170 includes a plurality of underfill sections (e.g., underfill sections 172a, 172b) between the sidewalls 150s of the die 150 and the conductive features CF. Underfill portions 172a, 172b are formed on sidewalls 150s on each side of die 150 and extend over surface 140a of rerouting structure 140 between sidewalls 150s of die 150 and conductive features CF. The sidewalls 174 (i.e., outer sidewalls) of the underfill portions 172a, 172b have endpoints 176a located on the sidewalls 150s of the die 150, endpoints 176b located on the surface 140a of the redistribution structure 140, and inflection points TP located between the endpoints 176a, 176 b. In other words, the sidewall 174 includes a first sidewall 174a extending between the end point 176a and the inflection point TP and a second sidewall 174b extending between the inflection point TP and the end point 176 b. Thus, the underfill portions 172a, 172b may be divided into a first portion UP having a first sidewall 174a and a second portion LP having a second sidewall 174 b. The second portion LP is disposed between the rewiring structure 140 and the first portion UP. In some embodiments, the first sidewall 174a of the first portion UP is smooth and substantially linear without a turning point, and the first portion UP has a triangular shape. In some embodiments, the width W of the first portion UP_a(i.e., the shortest width between the side wall 150s and the first side wall 174a or the shortest width between the extension line of the side wall 150s and the first side wall 174 a) increases as the first portion UP becomes closer to the inflection point TP. In some embodiments, second sidewall 174b is substantially parallel to sidewall 150s of die 150, and second portion LP has a rectangular shape. In some embodiments, the width W of the second portion LP_b(i.e., the shortest width between the side wall 150s and the second side wall 174b or the shortest width between the extension line of the side wall 150s and the second side wall 174 b) remains substantially the same as the first portion UP becomes closer to the surface 140 a. In some embodiments, the sidewalls of the temporary underfill termination 160 may not be smooth due to the temporary underfillTherefore, from a microscopic perspective, the second sidewall 174b of the second portion LP may have an undulating surface.

In some embodiments, underfill portions 172a, 172b have a width W1 measured from an extension of sidewall 150s to endpoint 176b and a width W2 measured from sidewall 150s of die 150 (or an extension of sidewall 150s of die 150) to inflection point TP. Width W1 is also referred to as the bottom width of second portion LP, and width W2 is also referred to as the bottom width of first portion UP. In some embodiments, width W2 is substantially equal to width W1, and widths W1, W2 are also the maximum widths of underfill portions 172a, 172 b. In some embodiments, the widths W1, W2 may be in the range of 5 μm to 1800 μm. Both width W1 and width W2 of underfill portions 172a, 172b are less than the distance D between die 150 and conductive feature CF. Thus, the underfill portions 172a, 172b are free from contact with the conductive features CF. In some embodiments, the underfill portions 172a, 172b have a height H measured from the surface 140a of the redistribution structure 140 to the end point 176 a. For example, the height H of the underfill section 172a is substantially the same as the height H of the underfill section 172 b. In some embodiments, the underfill portions (e.g., underfill portions 172a, 172b) located on different sidewalls 150s of the die 150 are all formed by partial contact with the temporary underfill termination 160, and thus the underfill portions have similar or substantially the same shape, height, width, etc. However, the present disclosure is not limited thereto. In some alternative embodiments, the underfill portions on different sidewalls of the die may have different shapes, heights, widths, etc.

Referring to fig. 1G, an encapsulant 180 is then formed over the redistribution structure 140 to encapsulate the conductive features CF, the die 150, and the underfill 170. The formation process and materials of the encapsulant 180 may be similar to those of the encapsulant 130, and thus, the details thereof are simplified for the sake of brevity. In some embodiments, the conductive features CF, the die 150, and the underfill 170 are initially overmolded with an insulating material. Next, a thinning process is performed to reduce the thickness of the insulating material until at least a portion of the conductive feature CF is exposed, so as to form the encapsulant 180. In some embodiments, the conductive features CF and/or the die 150 are slightly removed during the thinning process. In some embodiments, die 150 is ground until TSV158 is exposed. After forming the encapsulant 180, a surface 180a of the encapsulant 180 may be substantially coplanar with the back surface 150b of the die 150 (e.g., opposite the front surface 150 a) and the top surface of the conductive features CF. In some embodiments, the conductive feature CF penetrates the encapsulant 180, and thus the conductive feature CF may also be referred to as an encapsulant through hole (TMV).

Following the above process, a rerouting structure 190 is formed on the surface 180a of the encapsulant 180, the back surface 150b of the die 150, and the top surfaces of the conductive features CF. The rerouting structure 190 is in physical and electrical contact with the conductive features CF. In some embodiments, rerouting structure 190 is in physical and electrical contact with TSV158 of die 150. The redistribution structure 190 may include a patterned dielectric layer 192 and a patterned conductive layer 194. In some embodiments, multiple polymer sub-layers (e.g., polymer sub-layers 192a, 192b) and multiple metal sub-layers (e.g., metal sub-layers 194a, 194b) are alternately stacked to form the redistribution structure 190. The number of polymer sublayers and metal sublayers is not limited in this disclosure. In some embodiments, the polymer sub-layers 192a and 192b are made of the same material, and the polymer sub-layers 192a and 192b may be collectively considered as the patterned dielectric layer 192. The metal sublayers 194a and 194b can be collectively referred to as a patterned conductive layer 194.

In an embodiment, the re-wiring structure 190 may be formed as follows. First, a polymer sub-layer 192a having a plurality of openings is formed over the surface 180a of the encapsulant 180, the back surface 150b of the die 150, and the top surface of the conductive features CF. The opening of the polymer sub-layer 192a may expose at least a portion of the conductive feature CF and/or at least a portion of the TSV158 of the die 150. Next, a conductive material is formed and patterned to form a metal sub-layer 194a on the surface of the polymer sub-layer 192a and inside the openings of the polymer sub-layer 192a so as to be in physical and electrical contact with the conductive features CF and/or the TSVs 158 of the die 150. Subsequently, a polymer sub-layer 192b is formed on the polymer sub-layer 192a to cover the metal sub-layer 194 a. The polymer sublayer 192b may have a plurality of openings that expose at least a portion of the metal sublayer 194 a. Thereafter, a metal sub-layer 194b is formed on the polymer sub-layer 192b and within the opening of the polymer sub-layer 192b and the metal sub-layer 194b is patterned so as to be in physical and electrical contact with the underlying metal sub-layer 194 a. In some embodiments, metal sub-layer 194b includes an under-ball metal (UBM) pattern (not shown) or a bonding pad for further electrical connection. It is understood that the number of polymer sublayers and metal sublayers may depend on the circuit design, which is not limited in this disclosure.

After forming the redistribution structure 190, a plurality of conductive terminals 196 may be formed on the redistribution structure 190. For example, each conductive terminal 196 includes a first portion 196a and a second portion 196 b. A first portion 196a is formed on the metal sub-layer 194b of the rerouting structure 190 and a second portion 196b is formed on the first portion 196 a. In some embodiments, the first portion 196a is made of a different material than the second portion 196 b. For example, the first portion 196a is substantially a layer of conductive material comprising: pure elemental copper, copper containing unavoidable impurities, or copper alloys containing small amounts of elements such as tantalum, indium, tin, zinc, titanium, germanium, platinum, aluminum, and the like. The second portion 196b may include a solder material comprising: an alloy of tin, lead, silver, copper, nickel, bismuth, or a combination thereof. In some embodiments, the conductive terminals 196 may be arranged in an array. For example, the conductive terminals 196 include controlled collapse die connection (C4) bumps, micro bumps, conductive pillars, bumps formed by electroless nickel-palladium immersion gold (epig), combinations thereof (e.g., metal pillars with attached solder caps), and the like.

Referring to fig. 1H, the temporary carrier C is detached and removed from the overlying structure. In some embodiments, the structure shown in fig. 1H is flipped over (e.g., flipped upside down) and placed on a holder (holder) HD, such as a frame tape for a peeling process of temporary carrier C. For example, the release layer DB (e.g., LTHC release layer) is irradiated with a UV laser so that the temporary support C and the release layer DB are easily peeled off from the underlying structure. However, the lift-off process is not so limited, and other suitable lift-off methods may be used in some alternative embodiments.

Referring to fig. 1I, after the temporary carrier C is removed, the adhesive layer AD is removed from the encapsulation structure 100. In some embodiments, a dry cleaning process is performed to remove the adhesion layer AD. The dry cleaning process may use O₂System plasma, Ar system plasma, CF₄Is plasma, N₂Plasma, combinations thereof, or other suitable plasmas. In some embodiments, during the removal process of the adhesion layer AD, a portion of the encapsulant 130 exposed after the adhesion layer AD is removed may be partially removed. Thus, a surface 130b of the encapsulant 130 (e.g., opposite the surface 130 a) is lower than a back surface 110b of the die 110 (e.g., opposite the front surface 110 a) and a back surface 120b of the die 120 (e.g., opposite the front surface 120 a). In other words, the surface 130b of the encapsulant 130 is recessed relative to the back surfaces 110b, 120b of the dies 110, 120. A step height SH is formed between the encapsulant 130 and the die 110 and between the encapsulant 130 and the die 120. For example, the step height SH is in the range of 2 μm to 50 μm. In some embodiments, after removing adhesive layer AD, a total thickness T1 of semiconductor substrate 112 and protective layer 116 of die 110 is greater than a thickness T2 of encapsulant 130. Similarly, the total thickness T1 of semiconductor substrate 122 and protective layer 126 of die 120 is greater than the thickness T2 of encapsulant 130. In one embodiment, thickness T1 is in a range from 100 μm to 700 μm. However, the disclosure is not limited thereto, and in some alternative embodiments, the adhesive layer AD may be removed by other suitable processes, and the surface 130b of the encapsulation 130 is substantially flush with the rear surface 110b of the die 110 and the rear surface 120b of the die 120.

Conventionally, when an adhesive layer (e.g., DAF) is removed by a wet cleaning process using a chemical solution, the chemical solution may easily damage conductive terminals such as C4 bumps by diffusing into the gap between the package structure and the holder and then penetrating the sidewalls of the conductive terminals. In contrast, embodiments use a dry cleaning process to prevent damage to the conductive terminals 196. In an embodiment, the surface of the conductive terminals 196 is observed to be smooth and clean. In other words, the conductive terminals 196 are not damaged by the cleaning agent used to remove the adhesive layer AD.

After removing the adhesive layer AD, a singulation process is performed to form a plurality of semiconductor packages SP illustrated in fig. 1J. In some embodiments, the cutting process or singulation process generally involves cutting with a rotating blade or laser beam. In other words, the cutting or singulation process is, for example, a laser cutting process, a mechanical cutting process, or other suitable process. In some embodiments, the semiconductor package SP may be referred to as an integrated fan-out (InFO) package. However, the present disclosure is not limited thereto. In some alternative embodiments, the semiconductor package SP may be other types of packages.

In some embodiments, by using a temporary underfill termination, the underfill is prevented from seeping into and damaging conductive features such as TMV. Thus, the process window for the underfill dispensing process is increased and the distance between the die, e.g., a bridge die, and the conductive features, e.g., TMVs, may be reduced. Therefore, the size of the semiconductor package can be further reduced. In addition, the adhesive layer can be removed through a dry cleaning process, and the conductive terminal can be prevented from being damaged. Based on the above, the product yield can be improved.

Fig. 3A-3F are schematic cross-sectional views of various stages of fabricating a semiconductor package, according to some embodiments. The method illustrated in fig. 3A-3F is similar to the method illustrated in fig. 1A-1I, and thus the same reference numerals are used to refer to the same and similar parts and will not be described again herein. The main differences are set forth below.

Referring to fig. 3A, a structure is formed on a temporary carrier C having a release layer DB thereon. The structure is similar to that shown in fig. 1C, and differs in that the adhesive layer AD is formed under the dies 110, 120, respectively, without extending onto the temporary carrier C. Thus, as shown in fig. 3A, the back surfaces 110b, 120b of the dies 110, 120 are not flush with the surface 130b of the encapsulant 130, and the surface of the adhesive layer AD is substantially flush with the surface 130b of the encapsulant 130.

Next, a temporary underfill termination 160 is formed on the surface 140a of the rewiring structure 140 between the die 150 and the conductive features CF. In some embodiments, the temporary underfill termination 160 may have a box shape that surrounds the die 150 when viewed from a top view. Referring to fig. 3A, the cross-sectional shape of the temporary underfill termination 160 may have a mound shape in which the width W of the temporary underfill termination 160 increases as the temporary underfill termination 160 becomes closer to the surface 140a of the rewiring structure 140. In some embodiments, the width W of the temporary underfill termination 160 is in the range of 50 μm to 1000 μm. The height H of the temporary underfill terminator 160 is less than the height of the die 150. In some embodiments, as shown in fig. 3A, the height H may be in the range of 10 μm to 1000 μm.

Referring to fig. 3B, after the temporary underfill terminator 160 is formed, an underfill 170 is formed between the temporary underfill terminator 160, the die 150, and the redistribution structure 140. The method of forming the underfill 170 may be similar to the method of forming the underfill 170 as described with respect to fig. 1E and 2B, and thus will not be described in detail herein.

Referring to fig. 3C, after the underfill 170 is formed, the temporary underfill stopper 160 is removed. The method of removal of the temporary underfill terminator 160 may be similar to the method of removal of the temporary underfill terminator 160 as described with respect to fig. 1F, and thus will not be described in detail herein.

During formation, portions of the underfill 170 are in contact with the temporary underfill stop 160, and thus the shape of the underfill 170 may be defined in part by the temporary underfill stop 160. In some embodiments, when the temporary underfill stop 160 is mound-shaped, the underfill 170 may have a diamond shape due to the shape and height of the temporary underfill stop 160. The underfill 170 encapsulates portions of the sidewalls 150s of the die 150 and partially exposes the sidewalls 150s of the die 150 (i.e., the top portions of the sidewalls 150 s). In some embodiments, the underfill 170 includes a plurality of underfill portions (e.g., underfill portions 172a, 172b) between the sidewalls 150s of the die 150 and the conductive features CF. Underfill portions 172a, 172b are formed onOn sidewalls 150s at each side of die 150 and extending over surface 140a of rerouting structure 140 between sidewalls 150s of die 150 and conductive features CF. The sidewalls 174 of the underfill portions 172a, 172b have endpoints 176a located on the sidewalls 150s of the die 150, endpoints 176b located on the surface 140a of the redistribution structure 140, and transition points TP located between the endpoints 176a, 176 b. In other words, the sidewall 174 includes a first sidewall 174a extending between the end point 176a and the inflection point TP and a second sidewall 174b extending between the inflection point TP and the end point 176 b. Thus, the underfill portions 172a, 172b may be divided into a first portion UP having a first sidewall 174a and a second portion LP having a second sidewall 174 b. The second portion LP is disposed between the rewiring structure 140 and the first portion UP. In some embodiments, the first sidewall 174a of the first portion UP is smooth and substantially linear without a turning point, and the first portion UP has a triangular shape. In some embodiments, the width W of the first portion UP_a(i.e., the width between the sidewall 150s and the first sidewall 174a or the width between the extension line of the sidewall 150s and the first sidewall 174 a) increases as the first portion UP becomes closer to the inflection point TP. In some embodiments, the second sidewall 174b is non-linear and has at least one curvature. The curvature of the second side wall 174b is complementary to the curvature of the side wall of the hill-like temporary underfill termination 160. The second sidewall 174b may have various tangential slopes, and the tangential slope increases as the second sidewall 174b becomes closer to the turning point TP. In some embodiments, the width W of the second portion LP_b(i.e., the width between the side wall 150s and the second side wall 174b or the width between the extension line of the side wall 150s and the second side wall 174 b) increases as the second portion LP becomes closer to the surface 140 a.

In some embodiments, underfill portions 172a, 172b have a width W1 measured from an extension of sidewall 150s to endpoint 176b and a width W2 measured from sidewall 150s of die 150 (or an extension of sidewall 150s of die 150) to inflection point TP. Width W1 is also referred to as the bottom width of second portion LP, and width W2 is also referred to as the bottom width of first portion UP. In some embodiments, width W2 is greater than width W1, and width W2 is also the maximum width of underfill portions 172a, 172 b. In some embodiments, width W1 may be in the range of 5 μm to 1800 μm, and width W2 may be in the range of 5 μm to 1800 μm. Both width W1 and width W2 of underfill portions 172a, 172b are less than the distance D between die 150 and conductive feature CF. Thus, the underfill portions 172a, 172b do not contact the conductive features CF. In some embodiments, the underfill portions 172a, 172b have a height H measured from the surface 140a of the redistribution structure 140 to the end point 176 a. For example, the height H of the underfill section 172a is substantially the same as the height H of the underfill section 172 b. In some embodiments, the underfill portions (e.g., underfill portions 172a, 172b) located on different sidewalls 150s of the die 150 are all formed by partial contact with the temporary underfill termination 160, and thus the underfill portions have similar or substantially the same shape, height, width, etc. However, the present disclosure is not limited thereto. In some alternative embodiments, the underfill portions on different sidewalls of the die may have different shapes, heights, widths, etc.

Referring to fig. 3D, an encapsulant 180, a redistribution structure 190, and a plurality of conductive terminals 196 are sequentially formed on the redistribution structure 140, the die 150, and the underfill 170. Then, the formed structure is disposed on the holder HD, and the temporary carrier C and the peeling layer DB are peeled off from the structure below.

Referring to fig. 3E, after removing the temporary carrier C and the peeling layer DB, the adhesive layer AD is removed. In some embodiments, a dry cleaning process is performed to remove the adhesion layer AD. The dry cleaning process may use O₂System plasma, Ar system plasma, CF₄Is plasma, N₂Plasma, combinations thereof, or other suitable plasmas. In some embodiments, during the removal process of the adhesion layer AD, the surface 130b of the encapsulant 130 is exposed to a dry cleaning process and partially removed. Thus, the surface 130b of the encapsulant 130 is substantially flush with the back surfaces 110b, 120b of the dies 110, 120. After removing the adhesive layer AD, a singulation process is performed to form a plurality of semiconductor packages SP1 shown in fig. 3F.

Fig. 4A-4D are schematic cross-sectional views of various stages of fabricating a semiconductor package, according to some embodiments. The method illustrated in fig. 4A-4D is similar to the method illustrated in fig. 1A-1I, and thus the same reference numerals are used to refer to the same and similar components and will not be described again herein. The main differences are set forth below.

Referring to fig. 4A, a temporary underfill termination 160 is formed on the surface 140a of the rerouting structure 140 between the die 150 and the plurality of conductive features CF. The structure shown in fig. 4A is similar to that shown in fig. 1E, and the main difference is in the shape of the temporary underfill stop 160. In some embodiments, the temporary underfill terminator 160 may have a box shape as viewed from the top view, and as shown in fig. 4A, the cross-sectional shape of the temporary underfill terminator 160 may be like a bottom truncated ball. In some embodiments, the radius R of the temporary underfill termination 160 may be in the range of 50 μm to 1000 μm. The height H of the temporary underfill terminator 160 is less than the height of the die 150. In some embodiments, the height H may be in the range of 10 μm to 1000 μm.

Referring to fig. 4B, after the temporary underfill terminator 160 is formed, an underfill 170 is formed between the temporary underfill terminator 160, the die 150, and the redistribution structure 140. The method of forming the underfill 170 may be similar to the method of forming the underfill 170 in fig. 1E and 2B, and thus is not described in detail herein.

Referring to fig. 4C, after the underfill 170 is formed, the temporary underfill stopper 160 is removed. The removal method of the temporary underfill terminator 160 may be similar to the removal method of the temporary underfill terminator 160 in fig. 1F, and thus, the detailed description thereof is omitted herein.

During formation, portions of the underfill 170 are in contact with the temporary underfill stop 160, and thus the shape of the underfill 170 may be defined in part by the temporary underfill stop 160. In some embodiments, when the temporary underfill stop 160 has a spherical shape, the underfill 170 may have a shape as shown in fig. 4C due to the shape and height of the temporary underfill stop 160. Underfill 170 packageEncapsulating portions of the sidewalls 150s of the die 150 and partially exposing the sidewalls 150s of the die 150 (i.e., the top portions of the sidewalls 150 s). In some embodiments, the underfill 170 includes a plurality of underfill portions (e.g., underfill portions 172a, 172b) between the sidewalls 150s of the die 150 and the conductive features CF. Underfill portions 172a, 172b are formed on sidewalls 150s at each side of die 150 and extend over surface 140a of rerouting structure 140, between sidewalls 150s of die 150 and conductive features CF. The sidewalls 174 of the underfill portions 172a, 172b have endpoints 176a located on the sidewalls 150s of the die 150, endpoints 176b located on the surface 140a of the redistribution structure 140, and transition points TP located between the endpoints 176a, 176 b. In other words, the sidewall 174 includes a first sidewall 174a extending between the end point 176a and the inflection point TP and a second sidewall 174b extending between the inflection point TP and the end point 176 b. Thus, the underfill portions 172a, 172b may be divided into a first portion UP having a first sidewall 174a and a second portion LP having a second sidewall 174 b. The second portion LP is disposed between the rewiring structure 140 and the first portion UP. In some embodiments, the first sidewall 174a of the first portion UP is smooth and substantially linear without a turning point, and the first portion UP has a triangular shape. In some embodiments, the width W of the first portion UP_a(i.e., the width between the sidewall 150s and the first sidewall 174a or the width between the extension line of the sidewall 150s and the first sidewall 174 a) increases as the first portion UP becomes closer to the inflection point TP. In some embodiments, the second sidewall 174b is non-linear and has at least one curvature. The curvature of the second side wall 174b is complementary to the curvature of the side wall of the spherical temporary underfill termination 160. In some embodiments, the width W of the second portion LP_b(i.e., the width between sidewall 150s and second sidewall 174b or the width between the extension of sidewall 150s and second sidewall 174 b) decreases and then increases as second portion LP becomes closer to surface 140 a.

In some embodiments, underfill portions 172a, 172b have a width W1 measured from an extension of sidewall 150s to endpoint 176b and a width W2 measured from sidewall 150s of die 150 (or an extension of sidewall 150s of die 150) to inflection point TP. In some embodiments, width W1 is greater than width W2, and width W1 is also the maximum width of underfill portions 172a, 172 b. In some embodiments, width W1 may be in the range of 5 μm to 1800 μm, and width W2 may be in the range of 5 μm to 1800 μm. Both width W1 and width W2 of underfill portions 172a, 172b are less than the distance D between die 150 and conductive feature CF. Thus, the underfill portions 172a, 172b do not contact the conductive features CF. In some embodiments, the underfill portions 172a, 172b have a height H measured from the surface 140a of the redistribution structure 140 to the end point 176 a. For example, the height H of the underfill section 172a is substantially the same as the height H of the underfill section 172 b. In some embodiments, the underfill portions (e.g., underfill portions 172a, 172b) located on different sidewalls 150s of the die 150 are all formed by partial contact with the temporary underfill termination 160, and thus the underfill portions have similar or substantially the same shape, height, width, etc. However, the present disclosure is not limited thereto. In some alternative embodiments, the underfill portions on different sidewalls of the die may have different shapes, heights, widths, etc.

Next, an encapsulant 180, a redistribution structure 190 and a plurality of conductive terminals 196 are sequentially formed on the redistribution structure 140, the die 150 and the underfill 170. Thereafter, the temporary carrier C, the release layer DB, and the adhesive layer AD are removed in this order. Next, a singulation process is performed to form a plurality of semiconductor packages SP2 shown in fig. 4D.

In the above embodiment, the temporary underfill terminator 160 is continuously formed around the die 150. In other words, the temporary underfill terminator 160 is formed at all sides of the die 150. Thus, each sidewall of the underfill 170 has a shape complementary to the temporary underfill stop 160. However, in some alternative embodiments (not shown), the temporary underfill terminations 160 may not be formed at each side of the die 150. Therefore, only a portion of the sidewall of the underfill 170 that contacts the temporary underfill stopper 160 has a shape complementary to the temporary underfill stopper 160.

Fig. 5A-5F are schematic cross-sectional views of various stages of fabricating a semiconductor package, according to some embodiments.

Referring to fig. 5A, a plurality of dies 210, 220 and a plurality of conductive pillars CP are disposed on a temporary carrier C. In some embodiments, the release layer DB and the adhesion layer AD are sequentially formed on the temporary carrier C. In some embodiments, conductive pillars CP are disposed around the dies 210, 220 and between the dies 210, 220. Next, an encapsulant 230 is formed on the temporary carrier C to encapsulate the dies 210 and 220 and the conductive pillars CP. In some embodiments, the surface 230a of the encapsulant 230, the front surface 210a of the die 210, and the front surface 220a of the die 220 are substantially coplanar. Thereafter, a re-routing structure 240 is formed on the encapsulant 230 to electrically connect to the dies 210, 220 and the conductive pillars CP. The dies 210 and 220, the encapsulant 230, and the redistribution structure 240 may be similar to the dies 110 and 120 and the encapsulant 130 in fig. 1A and the redistribution structure 190 in fig. 1G, and thus are not described in detail herein. For example, the die 210 includes a semiconductor substrate 212, conductive connections 214 distributed over the semiconductor substrate 212, and a protective layer 216 disposed on the semiconductor substrate 212 and covering the conductive connections 214 for protection. The die 220 may include a semiconductor substrate 222, conductive connections 224 distributed over the semiconductor substrate 222, and a protective layer 226 disposed on the semiconductor substrate 222 and covering the conductive connections 224 for protection. The redistribution structure 240 may include a patterned dielectric layer 242 and a patterned conductive layer 244. In some embodiments, multiple polymer sublayers (e.g., polymer sublayers 242a, 242b) and multiple metal sublayers (e.g., metal sublayers 244a, 244b) are alternately stacked to form the redistribution structure 240.

Next, a plurality of conductive features CF and at least one die 250 are formed on the surface 240a of the rerouting structure 240. In some embodiments, the distance (i.e., shortest distance) D between the die 250 and the conductive features CF is in the range of 50 μm to 1000 μm. In some embodiments, a plurality of under-ball metal (UBM) patterns (e.g., metal sub-layer 244b) may be formed in the outermost polymer sub-layer 242b of the rerouting structure 240. The conductive feature CF may be disposed over the UBM pattern. In some embodiments, the conductive features CF are attached to the UBM pattern by solder flux (solder flux). In some embodiments, the conductive features CF are solder balls and are formed as a Ball Grid Array (BGA). In some embodiments, the conductive feature CF may be disposed on the re-routing structure 240 through a ball placement process and/or a reflow process. In some alternative embodiments, the conductive features CF are C4 bumps, micro bumps, conductive pillars, bumps formed by ENEPIG, combinations thereof (e.g., metal pillars with attached solder caps), and the like.

In some embodiments, die 250 is an Integrated Passive Device (IPD) die, and die 250 may include resistors, capacitors, inductors, and so forth. In some embodiments, die 250 is electrically connected to rerouting structure 240 by a plurality of solder connections 252 disposed between die 250 and rerouting structure 240. Solder connections 252 may be similar to solder connections 159 in fig. 1C and therefore will not be described in detail herein.

Referring to fig. 5B and fig. 6A, which is a top view of fig. 5B, a temporary underfill termination 260 is formed on the surface 240a of the rerouting structure 240 between the die 250 and the conductive features CF. In some embodiments, a temporary underfill termination 260 is formed on the outermost polymer sublayer 242 b. The temporary underfill termination 260 is disposed between the conductive features CF and the die 250 and is separate from the conductive features CF and the die 250, in other words, the temporary underfill termination 260 does not contact the conductive features CF and the die 250. In some embodiments, the temporary underfill termination 260 is formed at only a single side 250a of the die 250. In some embodiments, side 250a is selected as the dispensing location for the underfill. In some embodiments, the temporary underfill terminator 260 is formed by dispensing the material of the temporary underfill terminator 260 along the side 250a of the die 250 and then curing the material. In some embodiments, as shown in fig. 6A, temporary underfill terminator 260 is bar-shaped, and as shown in fig. 5B, temporary underfill terminator 260 has a cross-sectional shape such as a column with a curved top surface. The material and formation method of the temporary underfill terminator 260 may be similar to those of the temporary underfill terminator 160 in fig. 1D, and thus will not be described in detail herein. Further, depending on design, in some alternative embodiments, the temporary underfill terminations may be located at more than one side of the die.

Referring to fig. 5C and 6B, which is a top view of fig. 5B, after forming the temporary underfill termination 260, an underfill 270 is formed between the die 250 and the conductive features CF and between the die 250 and the redistribution structure 240. In some embodiments, the material of the underfill 270 is initially dispensed at the side 250a (i.e., the dispensing location) between the sidewall 250s of the die 250 and the temporary underfill termination 260. For example, a one-sided distributed process (one-sided distributed process) is used. By capillary action, the material of the underfill 270 flows between the dies 250 and to the other sides 250b, 250c, 250d of the dies 250. Next, a curing process is performed to harden the material of underfill 270 to form underfill 270.

Traditionally, the underfill that is formed is prone to oozing out to conductive features adjacent to the dispensing location, as the amount of material remaining in the underfill at the dispensing location may be much greater than at other locations. In some embodiments, a temporary underfill stop 260 is formed at the dispensing location to restrict or prevent the material of the underfill 270 from flowing to seep outwardly at an undesired width. Thus, the above embodiments prevent the underfill 270 from contacting and bleeding to the conductive features CF adjacent to the dispensing location (i.e., the side 250a of the die 250). Thus, cracking and breaking connections of the conductive features CF may be prevented during subsequent thermal processes. Furthermore, the underfill 270 may cover the solder connections 252 of the die 250 and the outermost metal sub-layer 244b of the redistribution structure 240, thereby enhancing the adhesion and helping prevent thermal stress from breaking the connection therebetween.

In some embodiments, the distance D between the die 250 and the conductive features CF at the side 250a is substantially the same as the distance between the die 250 and the conductive features CF at the other sides 250b, 250c, 250D. However, the present disclosure is not limited thereto. In some alternative embodiments, the distance D between the die 250 and the conductive feature CF at the side 250a is different than the distance between the die 250 and the conductive feature CF at the other side 250b, 250c, or 250D. For example, the distance D between the die 250 and the conductive features CF at the side 250a is less than the distance between the die 250 and the conductive features CF at the other sides 250b, 250c, 250D of the die 250. In other words, the conductive features CF at the side 250a are disposed at a position closer to the die 250 than the conductive features CF at the other sides 250b, 250c, 250 d. Because the distance between the die 250 and the conductive features CF immediately adjacent to the die 250 is short at the side 250a of the die 250, the underfill 270 may easily bleed into and contact the conductive features CF at the side 250 a. In this case, the temporary underfill stop 260 may be located only at side 250a to prevent the underfill 270 from seeping out to the conductive features CF at side 250 a.

Referring to fig. 5D, after the underfill 270 is formed, the temporary underfill stopper 260 is removed. The removal method of the temporary underfill terminator 260 may be similar to the removal method of the temporary underfill terminator 160 in fig. 1F, and thus will not be described in detail herein.

During formation, portions of the underfill 270 are in contact with the temporary underfill stop 260, and thus the shape of the underfill 270 may be defined in part by the temporary underfill stop 260. The underfill 270 encapsulates portions of the sidewalls 250s of the die 250 and partially exposes the sidewalls 250s of the die 250 (i.e., the top portions of the sidewalls 250 s). In some embodiments, underfill 270 includes a plurality of underfill portions (e.g., underfill portions 272a, 272b) located between sidewalls 250s of die 250 and conductive features CF. As shown in fig. 5C and 6B, underfill portion 272a at side 250a is formed by partially contacting temporary underfill termination 260, while other underfill portions (e.g., underfill portion 272B) at sides 250B, 250C, 250d are not. Thus, the shape of the underfill portion 272a may be different from the shape of the other underfill portions. In some embodiments, the sidewall 274 of the underfill portion 272a has a terminal 276a located on the sidewall 250s of the die 250, a terminal 276b located on the surface 240a of the redistribution structure 240, and a transition point TP located between the terminals 276a, 276 b. Changeable pipeIn other words, the sidewall 274 includes a first sidewall 274a extending between the end point 276a and the inflection point TP and a second sidewall 274b extending between the inflection point TP and the end point 276 b. Accordingly, underfill portion 272a may be divided into a first portion UP having a first sidewall 274a and a second portion LP having a second sidewall 274 b. In some embodiments, the width W of the first portion UP_aIncreases as the first portion UP becomes closer to the turning point TP, and the width W of the second portion LP_bAre substantially the same. In some embodiments, underfill portion 272a may be similar to underfill portion 172a shown in FIG. 1F, and thus will not be described in detail herein.

In some embodiments, underfill portion 272a has a width W1 measured from an extension of sidewall 250s of die 250 to an endpoint 276b of underfill portion 272a and a width W2 measured from sidewall 250s of die 250 (or an extension of sidewall 250s of die 250) to a turning point TP. Width W1 is also referred to as the bottom width of second portion LP, and width W2 is also referred to as the bottom width of first portion UP. In some embodiments, width W2 is substantially equal to width W1, and widths W1, W2 are also the maximum widths of underfill portion 272 a. In some embodiments, the widths W1, W2 may be in the range of 5 μm to 1800 μm. Both width W1 and width W2 of underfill portion 272a are less than the distance D between die 250 and conductive feature CF. Thus, the underfill portion 272a is free from contact with the conductive features CF.

In some embodiments, the underfill portion at side 250b, 250c, or 250d (e.g., underfill portion 272b at side 250 b) is formed without temporary underfill termination 260, and thus the sidewalls of the underfill portion at side 250b, 250c, or 250d (e.g., sidewall 274 of underfill portion 272b at side 250 b) are smooth and curved without inflection points. For example, the sidewalls 274 of the underfill portion 272b extend from the end point 276a on the sidewall 250s of the die 250 to the end point 276b on the surface 240a of the redistribution structure 240 without a turning point. In some embodiments, underfill portion 272b has a cross-sectional shape such as a triangle or other suitable shape. In some embodiments, underfill portion 272b has a width W measured from an extension of sidewall 250s of die 250 to any intermediate point between end points 276a, 276b, and the width W increases as underfill portion 272b becomes closer to surface 240a of rerouting structure 240. Underfill portion 272b has a maximum width W3 at the bottom, measured from an extension of sidewall 250s of die 250 to an endpoint 276b of underfill portion 272 b. The maximum width W3 is less than the distance D between the die 250 and the conductive feature CF. Thus, the underfill portion 272b is free from contact with the conductive feature CF. For example, the maximum width W3 of underfill portion 272b may be less than the maximum width (i.e., widths W1, W2) of underfill portion 272 a.

In some embodiments, underfill portion 272a has a height H1 measured from surface 240a of rerouting structure 240 to endpoint 276a of underfill portion 272a, and underfill portion 272b has a height H2 measured from surface 240a of rerouting structure 240 to endpoint 276a of underfill portion 272 b. In some embodiments, height H1 of underfill portion 272a may be greater than height H2 of underfill portion 272 b. However, the present disclosure is not limited thereto. In some alternative embodiments, height H1 of underfill portion 272a is not greater than height H2 of underfill portion 272 b. Furthermore, in some embodiments, underfill portion 272a has a different shape than the other underfill portions. However, the present disclosure is not limited thereto. In some alternative embodiments, if a temporary underfill termination is located at more than one side of die 250, another underfill portion may have a similar shape or the same shape as underfill portion 272 a.

Referring to fig. 5E, the formed structure is disposed on the holder HD. The temporary carrier C and the peeling layer DB are peeled off from the underlying structure. After that, the adhesive layer AD is removed. The adhesive layer AD may be removed by the method described in fig. 1I or other suitable methods. In some embodiments, after the adhesion layer AD is removed by the dry cleaning process, the surface 230b of the encapsulant 230 (e.g., opposite to the surface 230 a) is lower than the back surface 210b of the die 210 (e.g., opposite to the front surface 210 a) and the back surface 220b of the die 220 (e.g., opposite to the front surface 220 a). In other words, a step height SH is formed between the encapsulant 230 and the die 210 and between the encapsulant 230 and the die 220. For example, the step height SH is in the range of 2 μm to 50 μm.

After removing the adhesive layer AD, a singulation process is performed to form a plurality of semiconductor packages SP3 shown in fig. 5F. In some embodiments, the singulation process may be similar to that in fig. 1J. In some embodiments, semiconductor package SP3 may be referred to as an integrated fan out (InFO) package. However, the present disclosure is not limited thereto. In some alternative embodiments, the semiconductor package SP3 may be other types of packages.

In some alternative embodiments, underfill portion 272a at side 250a may have other configurations depending on the shape of the temporary underfill termination. For example, as shown in fig. 7 and 8, in semiconductor packages SP4, SP5, underfill portion 272a at side 250a has a shape similar to underfill portion 172a in fig. 3C and 4C.

In some embodiments, by using a temporary underfill termination, the underfill is prevented from seeping into and damaging conductive features such as BGA's. The dispensing speed of the underfill can be increased to save time since bleeding issues need not be considered. Thus, the process window for the underfill dispensing process is increased and the distance between the die, e.g., IPD, and the conductive features, e.g., BGA, may be reduced. Therefore, the size of the semiconductor package can be further reduced. Furthermore, since the temporary underfill terminator is removed after the underfill is formed, there is no need to consider the reliability problem of the temporary underfill terminator. In addition, the adhesive layer can be removed by a dry cleaning process, and the conductive features can be protected from damage. Based on the above, the yield of the product can be improved.

According to some embodiments of the present disclosure, a semiconductor package includes a die and an underfill. The die is disposed over the surface and includes a first sidewall. The underfill encapsulates the die. The underfill includes a first underfill portion on the first sidewall, and in cross-section, a second sidewall of the first underfill portion has a hinge point.

In some embodiments, the second sidewall further comprises a first end point on the first sidewall and a second end point on the surface, and the inflection point is located between the first end point and the second end point.

In some embodiments, a distance between the first sidewall and the inflection point or between an extension of the first sidewall and the inflection point is greater than a distance between the second endpoint and the extension of the first sidewall.

In some embodiments, a distance between the first sidewall and the inflection point or between an extension of the first sidewall and the inflection point is substantially the same as a distance between the second endpoint and the extension of the first sidewall.

In some embodiments, the underfill further comprises a second underfill portion on a third sidewall opposite the first sidewall of the die, and a fourth sidewall of the second underfill portion has no inflection points.

In some embodiments, the underfill further comprises a second underfill portion on a third sidewall opposite the first sidewall of the die, and a fourth sidewall of the second underfill portion has a hinge point.

According to some embodiments of the present disclosure, a semiconductor package includes a first die and an underfill. The first die is bonded to the surface and includes a first sidewall. An underfill encapsulates the first die and partially exposes the first sidewalls. The underfill includes a first underfill portion on the first sidewall. The first underfill portion includes a second sidewall. The width between the first sidewall and the second sidewall decreases or remains substantially the same as the first underfill portion becomes closer to the surface.

In some embodiments, at least a portion of the second sidewall of the underfill is substantially parallel to the first sidewall of the first die.

In some embodiments, the first underfill portion comprises a first portion and a second portion between the first portion and the surface, the first portion increasing in width as the first portion becomes closer to the surface, and the second portion decreasing in width as the second portion becomes closer to the surface.

In some embodiments, the first underfill portion comprises a first portion and a second portion between the first portion and the surface, the first portion increasing in width as the first portion becomes closer to the surface, and the second portion remaining substantially the same in width as the second portion becomes closer to the surface.

In some embodiments, the first underfill portion comprises a first portion and a second portion located between the first portion and the surface, the width of the first portion increasing as the first portion becomes closer to the inflection point, and the width of the second portion decreasing and then increasing as the second portion becomes closer to the surface.

In some embodiments, the semiconductor package further comprises a plurality of conductive features located alongside the first die, wherein the underfill is disposed between and separate from the die and the conductive features.

In some embodiments, the semiconductor package further comprises a second die and a third die, wherein the first die electrically connects the second die and the third die.

In some embodiments, the semiconductor package further comprises an encapsulant encapsulating the second die and the third die, wherein a surface of the encapsulant is recessed relative to surfaces of the second die and the third die.

According to some embodiments of the present disclosure, a method of manufacturing a semiconductor package includes the following steps. A plurality of conductive features are formed alongside the first die. A temporary underfill termination is continuously formed along at least one side of the first die between the first die and portions of the plurality of conductive features. An underfill paste is filled between the first die and the temporary underfill termination. The temporary underfill stop is removed.

In some embodiments, the temporary underfill termination is formed to surround all sidewalls of the first die.

In some embodiments, at least one side of the first die is not surrounded by the temporary underfill terminator.

In some embodiments, the cross-sectional shape of the temporary underfill termination comprises a post, a mound, or a sphere.

In some embodiments, in cross-sectional view, the sidewalls of the underfill have inflection points.

In some embodiments, the method further comprises: forming a second die and a third die having an adhesive layer thereunder, wherein the second die and the third die are electrically connected through the first die; and removing the adhesion layer by a dry cleaning process.

Other features and processes may also be included. For example, test structures may be included to facilitate verification testing of three-dimensional (3D) packages or three-dimensional integrated circuit (3D DIC) devices. The test structure may, for example, include test pads formed in a redistribution layer or on a substrate to enable testing of a 3D package or 3DIC, use of probes and/or probe cards (probe cards), and the like. Verification tests may be performed on the intermediate structures as well as the final structure. In addition, the structures and methods disclosed herein may be used in conjunction with testing methods that include intermediate verification of known good dies (known good die) to improve yield and reduce cost.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.