阅读说明：本技术 封装结构 (Packaging structure ) 是由 林士庭 吴集锡 余振华 卢思维 于 2020-09-21 设计创作，主要内容包括：一种封装结构包括多个半导体管芯、绝缘密封体、重布线层及多个连接元件。所述绝缘密封体包封所述多个半导体管芯。所述重布线层沿堆积方向设置在所述绝缘密封体上并电连接到所述多个半导体管芯,其中所述重布线层包括交替堆叠的多个导电线、多个导通孔及多个介电层,且所述多个导通孔的侧向尺寸沿着所述堆积方向增加。所述连接元件设置在所述重布线层与所述半导体管芯之间,其中所述连接元件包括与所述半导体管芯接合的本体部分及与所述重布线层接合的通孔部分,其中所述通孔部分的侧向尺寸沿着所述堆积方向减小。(A package structure includes a plurality of semiconductor dies, an insulating seal, a redistribution layer, and a plurality of connection elements. The insulating seal encapsulates the plurality of semiconductor dies. The redistribution layer is disposed on the insulating seal along a stacking direction and electrically connected to the plurality of semiconductor dies, wherein the redistribution layer includes a plurality of conductive lines, a plurality of vias, and a plurality of dielectric layers that are alternately stacked, and a lateral dimension of the plurality of vias increases along the stacking direction. The connecting element is disposed between the redistribution layer and the semiconductor die, wherein the connecting element includes a body portion bonded to the semiconductor die and a via portion bonded to the redistribution layer, wherein a lateral dimension of the via portion decreases along the stacking direction.)

1. A package structure, comprising:

a plurality of semiconductor die;

an insulating seal encapsulating the plurality of semiconductor die;

a redistribution layer disposed on the insulating seal and electrically connected to the plurality of semiconductor dies along a stacking direction, wherein the redistribution layer includes a plurality of conductive lines, a plurality of vias, and a plurality of dielectric layers that are alternately stacked, and a lateral dimension of the plurality of vias increases along the stacking direction; and

a plurality of connection elements disposed between the redistribution layer and the plurality of semiconductor dies, wherein the plurality of connection elements include body portions bonded to the plurality of semiconductor dies and via portions bonded to the redistribution layer, wherein a lateral dimension of the via portions decreases along the stacking direction.

Technical Field

The present disclosure relates to a package structure and a method for fabricating the same.

Background

The semiconductor industry has experienced rapid growth due to the ever-increasing integration density of various electronic components (i.e., transistors, diodes, resistors, capacitors, etc.). To a large extent, this increase in integration density is due to the repeated reduction in minimum feature size (minimum feature size), which allows more smaller components to be integrated into a given area. These smaller electronic components also require smaller packages that utilize smaller areas than previous packages. Three-dimensional integration techniques for wafer-level packaging are being developed to meet the demands for size reduction, high-performance interconnection, and heterogeneous integration of high-density integrated packages.

Disclosure of Invention

The embodiment of the disclosure provides a packaging structure which comprises a plurality of semiconductor dies, an insulating sealing body, a redistribution layer and a plurality of connecting elements. The insulating seal encapsulates the plurality of semiconductor dies. The redistribution layer is disposed on the insulating seal along a stacking direction and electrically connected to the plurality of semiconductor dies, wherein the redistribution layer includes a plurality of conductive lines, a plurality of vias, and a plurality of dielectric layers that are alternately stacked, and a lateral dimension of the plurality of vias increases along the stacking direction. The connecting element is disposed between the redistribution layer and the semiconductor die, wherein the connecting element includes a body portion bonded to the semiconductor die and a via portion bonded to the redistribution layer, wherein a lateral dimension of the via portion decreases along the stacking direction.

Drawings

The aspects of the present disclosure are best understood from the following detailed description when read with the accompanying drawing figures. Note that, according to standard practice in the industry, various features are not drawn to scale. In fact, the critical dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

Fig. 1A-1I are schematic cross-sectional views of various stages in a method of fabricating a package structure according to some example embodiments of the present disclosure.

Fig. 2A-2F are schematic cross-sectional views of various stages in a method of fabricating a package structure according to some other exemplary embodiments of the present disclosure.

Fig. 3 is a schematic cross-sectional view of a package structure according to some exemplary embodiments of the present disclosure.

Fig. 4 is a schematic cross-sectional view of a package structure according to some other exemplary embodiments of the present disclosure.

Fig. 5 is a schematic cross-sectional view of a package structure according to some other exemplary embodiments of the present disclosure.

Fig. 6A-6F are schematic cross-sectional views of various stages in a method of fabricating a package structure according to some other exemplary embodiments of the present disclosure.

Fig. 7A-7H are schematic cross-sectional views of various stages in a method of fabricating a package structure according to some other example embodiments of the present disclosure.

Fig. 8 is a schematic cross-sectional view of a package structure according to some other example embodiments of the present disclosure.

[ description of symbols ]

101: second carrier

102: first carrier/carrier

103. 104, DB: peeling layer

106: seed layer

106-TS, 112A-TS, 116-TS, 118-TS, 204-TS, CL1-TS, DL 1-TS: top surface

108: connecting seed layers

110: connecting element

110A, 130A: body part

110B, 130B: through hole part

112A: first semiconductor die/semiconductor die

112A-1: first semiconductor substrate/semiconductor substrate

112A-2: first conductive pad/conductive pad

112A-3: first passivation layer/passivation layer

112A-4: first conductive post/conductive post

112A-5, 112B-5: protective layer

112A-BS: backside surface of first semiconductor die

112B: second semiconductor die/semiconductor die

112B-1: second semiconductor substrate/semiconductor substrate

112B-2: second conductive pad/conductive pad

112B-3: second passivation layer/passivation layer

112B-4: second conductive post/conductive post

112B-BS: backside surface of second semiconductor die

112C, 112D: semiconductor die

112C-1, 112D-1: semiconductor substrate

112C-2, 112D-2, 122: conductive pad

112C-3, 112D-3: passivation layer

112C-4, 112D-4: conductive pole

114: conductive bump

116: underfill structure

118: insulating material

118': insulating seal

118' -Sx: surface of insulating seal

120: redistribution layer

121A, 121B, 121C: non-planar seed layer

124: conductive ball

130: insulator piercing

132. DLx: dielectric layer

134: conductive terminal

202: support structure

204: connecting column

301: strip tape

302: frame structure

CL 1: first conductive line

CL 2: second conductive line/conductive line

CL 3: third conductive line/conductive line

CLx: conductive wire

CR 1: carrier

D1: a first direction

DL 1: first dielectric layer/bottommost dielectric layer

DL 2: second dielectric layer/dielectric layer

DL 3: third dielectric layer/dielectric layer

DL 4: fourth dielectric layer/dielectric layer

H1: first height

H2: second height

H3: third height

H4: a fourth height

LD1, LD 2: lateral dimension

PH1, PH 2: height

PK1, PK2, PK3, PK4, PK5, PK6, PK7, PK 8: packaging structure

V1: first via/via

V2: second via/Via

V3, Vx: conducting hole

Detailed Description

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be limiting. For example, in the following description, a second feature formed over or on a first feature 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 feature and the first feature such that the second feature and the first feature may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. Such repetition 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 "below … (beneath)", "below … (below)", "below (lower)", "above … (on)", "above … (over)", "overlying … (overlapping)", "above … (above)", "upper (upper)" may be used herein to describe the relationship of one element or feature to another element(s) or feature(s) as shown in the figures for ease of illustration. 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 have other orientations (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly as well.

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 (3 DIC) devices. The test structure may include test pads formed, for example, in a redistribution layer or on a substrate, which allow 3D packages or 3DIC testing using probes and/or probe cards, and the like. Verification tests may be performed on the intermediate structures as well as the final structure. Additionally, the structures and methods disclosed herein may be used in conjunction with testing methods that include verifying known good dies at an intermediate stage to improve yield and reduce cost.

In the package structure, when semiconductor dies having different heights or thicknesses are used, various reliability problems may occur due to the grinding/planarization process for compensating for the height variations, such as cracks in the molding compound (encapsulant), cracks in the redistribution layer, or collapse of the redistribution layer. In some embodiments of the present disclosure, conductive bumps and pillars are used to compensate for die height variations. Thus, molding and grinding on the conductive pillars of the semiconductor die may be reduced. Therefore, cracks in the molding compound (encapsulant) and cracks in the rewiring layer can be further reduced. Furthermore, the conductive bumps and pillars may be used to obtain a large standoff (standoff) while maintaining a low pitch for heterobonding, thus improving the reliability window of the package structure.

Fig. 1A-1I are schematic cross-sectional views of various stages in a method of fabricating a package structure according to some example embodiments of the present disclosure. Referring to fig. 1A, a first carrier 102 is provided. In some embodiments, the first carrier 102 may be a glass carrier or any carrier suitable for carrying semiconductor wafers or reconstituted wafers for use in package structure manufacturing methods. In some embodiments, the first carrier 102 is coated with a release layer 104. The material of the exfoliation layer 104 may be any material suitable for bonding and exfoliating the first carrier 102 with an overlying layer or any wafer disposed thereon.

In some embodiments, the exfoliation layer 104 may include a layer of dielectric material made of a dielectric material including any suitable polymer-based dielectric material (e.g., benzocyclobutene ("BCB"), polybenzoxazole ("PBO")). In an alternative embodiment, the release layer 104 may comprise a layer of dielectric material made of an epoxy-based thermal release material that loses its adhesive properties when heated, such as a light-to-heat-conversion (LTHC) release coating film. In yet another alternative embodiment, the exfoliation layer 104 may include a layer of dielectric material made of ultra-violet (UV) glue that loses its adhesive properties when exposed to UV light. In certain embodiments, the peel-off layer 104 may be dispensed as a liquid and cured, or may be a laminated film laminated to the first carrier 102, or may be the like. The top surface of the exfoliation layer 104 opposite the bottom surface contacting the first carrier 102 may be flat and may have a high degree of coplanarity. In some embodiments, the peeling layer 104 is, for example, a LTHC layer having good chemical resistance, and such layer can be peeled from the first carrier 102 at room temperature by applying laser irradiation, although the disclosure is not limited thereto.

In an alternative embodiment, a buffer layer (not shown) may be coated on the exfoliation layer 104, with the exfoliation layer 104 sandwiched between the buffer layer and the first carrier 102, and the top surface of the buffer layer may further provide a high degree of coplanarity. In some embodiments, the buffer layer may be a layer of dielectric material. In some embodiments, the buffer layer may be a polymer layer made of polyimide, PBO, BCB, or any other suitable polymer-based dielectric material. In some embodiments, the buffer layer may be an Ajinomoto Buildup Film (ABF), a Solder mask (SR), or the like. In other words, the buffer layer is optional and may be omitted based on requirements, and thus the disclosure is not limited thereto.

In some embodiments, a seed layer 106 may be formed on the lift-off layer 104 or on the buffer layer (if present). In some embodiments, the seed layer 106 is a planar seed layer with a high degree of coplanarity. In some embodiments, the seed layer 106 may be a titanium/copper composite layer. However, the present disclosure is not so limited and other types of seed layers may be suitably used.

Referring to fig. 1B, after forming the seed layer 106, first conductive lines CL1 are formed over the seed layer 106. In some embodiments, the first conductive line CL1 may be made of a conductive material (e.g., aluminum, titanium, copper, nickel, tungsten, and/or alloys thereof) formed by electroplating or deposition, which may be patterned using photolithography and etching processes. In some embodiments, the first conductive line CL1 may be a patterned copper layer or other suitable patterned metal layer. Throughout this specification, the term "copper" is intended to include substantially pure elemental copper, copper containing unavoidable impurities, and copper alloys containing minor amounts of elements (e.g., tantalum, indium, tin, zinc, manganese, chromium, titanium, germanium, strontium, platinum, magnesium, aluminum, or zirconium, etc.). In some embodiments, the first conductive lines CL1 are formed to cover portions of the seed layer 106 while other portions of the seed layer 106 are exposed.

Referring to fig. 1C, in the next step, a first dielectric layer DL1 is formed to cover the first conductive line CL 1. In some embodiments, the material of the first dielectric layer DL1 may be polyimide, Polybenzoxazole (PBO), benzocyclobutene (BCB), nitride (e.g., silicon nitride), oxide (e.g., silicon oxide), phosphosilicate glass (PSG), borosilicate glass (BSG), boron-doped phosphosilicate glass (BPSG), combinations thereof, and the like, which may be patterned using photolithography and/or etching processes. In some embodiments, the material of the first dielectric layer DL1 may be formed by a suitable fabrication technique (e.g., spin-on coating, Chemical Vapor Deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), etc.). The present disclosure is not so limited.

As shown in fig. 1C, the first dielectric layer DL1 is patterned to have a plurality of openings exposing the surface of the first conductive line CL 1. In some embodiments, the connection seed layer 108 is formed within the plurality of openings and is electrically connected to the first conductive line CL 1. The connecting seed layer 108 may be similar to the material used for seed layer 106. Subsequently, a plurality of connection elements 110 are formed on the first dielectric layer DL1 and in the plurality of openings. In certain embodiments, connecting elements 110 are formed on and in physical contact with connecting seed layer 108. Further, the connection element 110 may be electrically connected to the first conductive line CL1 through the connection seed layer 108.

As further shown in fig. 1C, in some embodiments, the plurality of connecting elements 110 includes a body portion 110A and a through-hole portion 110B. In some embodiments, the via portions 110B are joined with the first conductive lines CL1 by the connecting seed layer 108. In certain embodiments, the via portion 110B is located between the body portion 110A and the connecting seed layer 108. Furthermore, in some embodiments, the lateral dimension LD1 of the via portion 110B decreases along the first direction D1 of the package structure.

Referring to fig. 1D, after the connection elements 110 are formed, the first semiconductor die 112A and the second semiconductor die 112B are disposed on the plurality of connection elements 110. The first semiconductor die 112A and the second semiconductor die 112B are disposed on the body portion 110A of the connection element 110 by flip-chip bonding (flip-chip bonding), for example. In some embodiments, the first semiconductor die 112A and the second semiconductor die 112B are electrically connected to the connection elements 110 by a plurality of conductive bumps 114. For example, the conductive bumps 114 are solder bumps, lead-free solder bumps, micro-bumps, and the like. Although only two semiconductor dies (112A and 112B) are shown herein, it should be noted that the number of semiconductor dies bonded to the connection element 110 is not so limited and this can be adjusted based on requirements. In the illustrated embodiment, the height of the first semiconductor die 112A may be different than the height of the second semiconductor die 112B. For example, the height of the first semiconductor die 112A is greater than the height of the second semiconductor die 112B.

In some embodiments, each of the first semiconductor die 112A and the second semiconductor die 112B includes a semiconductor substrate (first semiconductor substrate 112A-1/second semiconductor substrate 112B-1), a plurality of conductive pads (first conductive pad 112A-2/second conductive pad 112B-2), a passivation layer (first passivation layer 112A-3/second passivation layer 112B-3), and a plurality of conductive pillars (first conductive pillar 112A-4/second conductive pillar 112B-4).

As shown in FIG. 1D, the plurality of conductive pads (112A-2/112B-2) are disposed on a semiconductor substrate (112A-1/112B-1). A passivation layer (112A-3/112B-3) is formed over the semiconductor substrate (112A-1/112B-1) and has an opening that partially exposes the conductive pad (112A-2/112B-2) on the semiconductor substrate (112A-1/112B-1). The semiconductor substrate (112A-1/112B-1) may be a bulk silicon substrate or a silicon-on-insulator (SOI) substrate, and also includes active components (e.g., transistors, etc.) and optionally passive components (e.g., resistors, capacitors, inductors, etc.) formed therein. The conductive pads (112A-2/112B-2) may be aluminum pads, copper pads, or other suitable metal pads. The passivation layer (112A-3/112B-3) may be a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, or a dielectric layer formed from any suitable dielectric material. Furthermore, in some embodiments, a post-passivation layer (not shown) is optionally formed over the passivation layer (112A-3/112B-3). The post-passivation layer covers the passivation layer (112A-3/112B-3) and has a plurality of contact openings. The conductive pads (112A-2/112B-2) are partially exposed by the contact openings of the post-passivation layer. The post-passivation layer may be a benzocyclobutene (BCB) layer, a polyimide layer, a Polybenzoxazole (PBO) layer, or a dielectric layer formed of other suitable polymers. In some embodiments, the conductive posts (112A-4/112B-4) are formed on the conductive pads (112A-2/112B-2) by plating. In some embodiments, the first and second conductive pillars 112A-4 and 112B-4 of the first and second semiconductor dies 112A and 112B are electrically connected to the connection element 110 through the conductive bump 114. In other words, the first and second conductive pillars 112A-4 and 112B-4 may be physically bonded to the conductive bump 114 for electrical connection.

In some embodiments, the first semiconductor die 112A and the second semiconductor die 112B may be selected from application-specific integrated circuit (ASIC) chips, analog chips (e.g., wireless and rf chips), digital chips (e.g., baseband chips), Integrated Passive Devices (IPDs), voltage regulator chips, sensor chips, memory chips, and the like. The present disclosure is not so limited. In some embodiments, the first semiconductor die 112A and the second semiconductor die 112B are different types of semiconductor die. In some embodiments, the first semiconductor die 112A and the second semiconductor die 112B may be the same type of semiconductor die.

Furthermore, in the illustrated embodiment, after the first and second semiconductor dies 112A and 112B are disposed onto the connection element 110, the underfill structure 116 is formed on the first dielectric layer DL1 to cover the body portion 110A of the connection element 110 and to partially cover the first and second semiconductor dies 112A and 112B. In some embodiments, the underfill structure 116 surrounds the conductive pillars (112A-4/112B-4) of the first and second semiconductor dies 112A, 112B, and further surrounds the conductive bumps 114. In some embodiments, the underfill structure 116 fills the spaces between adjacent connection elements 110 and fills the spaces between adjacent conductive posts (112A-4/112B-4). In some embodiments, the underfill structure 116 covers the sidewalls of the first and second semiconductor dies 112A and 112B, while the backside surfaces 112A-BS and 112B-BS of the first and second semiconductor dies 112A and 112B are exposed. In certain embodiments, the width of the underfill structure 116 increases along the first direction D1.

Referring to fig. 1E, in a next step, an insulating material 118 is formed on the first dielectric layer DL1 to encapsulate the first semiconductor die 112A, the second semiconductor die 112B and surround the plurality of connection elements 110. In some embodiments, the insulating material 118 also surrounds the underfill structure 116. In some embodiments, the insulating material 118 is formed by, for example, a compression molding process, filling the gap between the first semiconductor die 112A and the second semiconductor die 112B. In some embodiments, the insulating material 118 also fills the gaps in the underfill structure 116. At this stage, the first and second semiconductor dies 112A and 112B are encapsulated and well protected by the insulating material 118. In other words, the first semiconductor die 112A and the second semiconductor die 112B are not exposed.

In some embodiments, the insulating material 118 includes a polymer (e.g., an epoxy, a phenolic, a silicon-containing, or other suitable resin), a dielectric material having low dielectric constant (Dk) and low loss tangent (Df) properties, or other suitable materials. In alternative embodiments, the insulating material 118 may comprise an acceptable insulating encapsulant material. In some embodiments, the insulating material 118 may further include an inorganic filler or inorganic compound (e.g., silica, clay, etc.) that may be added thereto to optimize the Coefficient of Thermal Expansion (CTE) of the insulating material 118. The present disclosure is not so limited.

Referring to fig. 1F, the insulating material 118 may be partially removed to expose the first semiconductor die 112A and the second semiconductor die 112B. In some embodiments, the insulating material 118 is ground or polished by a planarization step. The planarization step is performed, for example, by a mechanical grinding process and/or a Chemical Mechanical Polishing (CMP) process until the backside surfaces 112A-BS of the first semiconductor die 112A and the backside surfaces 112B-BS of the second semiconductor die 112B are exposed. In some alternative embodiments, a planarization step is not performed, and the insulating material 118 protects the backside surfaces 112A-BS and 112B-BS of the first and second semiconductor dies 112A and 112B.

In the illustrated embodiment, the insulating material 118 is polished to form an insulating seal 118'. In some embodiments, the surfaces 118 '-Sx of the insulating seal 118', the backside surface 112A-BS of the first semiconductor die 112A, and the backside surface 112B-BS of the second semiconductor die 112B are coplanar and flush with each other. In some embodiments, a cleaning step may be performed after a mechanical grinding or Chemical Mechanical Polishing (CMP) step, if desired. For example, a cleaning step is performed to clean and remove residues resulting from the planarization step. However, the present disclosure is not limited thereto, and the planarization step may be performed by any other suitable method.

Referring to fig. 1G, in the next step, the first carrier 102 is peeled off and separated from the seed layer 106. In some embodiments, the lift-off process includes projecting light, such as laser or UV light, onto the lift-off layer 104 (e.g., LTHC release layer) so that the first carrier 102 can be easily removed with the lift-off layer 104. In some embodiments, during the lift-off step, the structure shown in fig. 1F is flipped over and transferred onto a second carrier 101 having a lift-off layer 103 coated thereon. In some embodiments, the first semiconductor die 112A, the second semiconductor die 112B, and the insulating seal 118' are disposed on the lift-off layer 103 and over the second carrier 101 after the lift-off process.

In some embodiments, after transferring the components on the first carrier 102 to the second carrier 101, a planarization process may be performed to remove the seed layer 106. The planarization process is performed, for example, by a mechanical grinding process and/or a Chemical Mechanical Polishing (CMP) process until the first conductive line CL1 is exposed. In some embodiments, the seed layer 106 (or the planar seed layer) is completely removed by the planarization process. In some embodiments, after the planarization process, the top surface CL1-TS of the first conductive line CL1 is coplanar with the top surface DL1-TS of the first dielectric layer DL1, while the bottom surface of the first conductive line CL1 engages the via portion 110B of the connection element 110 (through the connection seed layer 108) and contacts the first dielectric layer DL 1.

Referring to fig. 1H, in the next step, a plurality of conductive lines (CL2, CL3), a plurality of vias (V1, V2), a plurality of non-planar seed layers (121A, 121B), and a plurality of dielectric layers (DL2, DL3, DL4) alternately stacked over the first conductive line CL1 and the first dielectric layer DL1 along the first direction D1 (or the stacking direction) are formed. For example, in the illustrated embodiment, a second dielectric layer DL2 is formed over the first dielectric layer DL1, wherein the second dielectric layer DL2 is patterned with a plurality of openings exposing the surface of the first conductive lines CL 1. Subsequently, a non-planar seed layer 121A is formed within the opening and over the second dielectric layer DL2, wherein the non-planar seed layer 121A contacts the first conductive lines CL 1. Thereafter, the first via hole V1 and the second conductive line CL2 are formed on the non-planar seed layer 121A and electrically connected to the first conductive line CL1 through the non-planar seed layer 121A.

In a similar manner, the third dielectric layer DL3, the non-planar seed layer 121B, the second via hole V2, the third conductive line CL3, and the fourth dielectric layer DL4 are sequentially formed and stacked along the first direction D1 (stacking direction) to constitute the rewiring layer 120. As shown in fig. 1H, the via portion 110B of the connection element 110 is surrounded by the bottommost dielectric layer (DL1) of the dielectric layer DLx of the rewiring layer 120. In some embodiments, the lateral dimension LD1 of the through-hole portion 110B decreases along the first direction D1 (stacking direction), while the lateral dimension LD2 of the via Vx increases along the first direction D1 (stacking direction). In certain embodiments, lateral dimensions LD1 and LD2 refer to the width of via portion 110B and the width of via Vx measured in a direction perpendicular to first direction D1 (the stacking direction). For example, a lateral dimension LD1 (or width) of the via portion 110B on a side connected to the body portion 110A is larger than a lateral dimension LD1 (or width) of the via portion 110B on a side connected to the first conductive line CL 1.

In an exemplary embodiment, the first dielectric layer DL1, the second dielectric layer DL2, the third dielectric layer DL3, and the fourth dielectric layer DL4 constitute the dielectric layer DLx of the rewiring layer 120. Further, the first conductive line CL1, the second conductive line CL2, and the third conductive line CL3 constitute a conductive line CLx of the rewiring layer 120. The first via hole V1 and the second via hole V2 form a via hole Vx of the rewiring layer 120. The materials for the second, third and fourth dielectric layers DL2, DL3 and DL4 are similar to the materials for the first dielectric layer DL 1. In addition, materials for the second conductive line CL2, the third conductive line CL3, the first via hole V1, and the second via hole V2 may be similar to those for the first conductive line CL 1. In an exemplary embodiment, the first dielectric layer DL1 has a first height H1, the second dielectric layer DL2 has a second height H2, the third dielectric layer DL3 has a third height H3, and the fourth dielectric layer DL4 has a fourth height H4, wherein H1> H2-H3-H4. In other words, the first dielectric layer DL1 may have a height (or thickness) greater than the remaining dielectric layer DLx.

In an exemplary embodiment, although only four dielectric layers DLx and three conductive lines CLx are illustrated herein, the present disclosure is not limited thereto. In alternative embodiments, the number of layers of dielectric layer DLx and conductive line CLx formed may be adjusted based on design requirements. Similarly, the number of vias Vx used can be adjusted based on the number of conductive lines CLx present.

After forming the redistribution layer 120, a plurality of conductive pads 122 may be disposed on the exposed top surfaces of the topmost conductive line CLx (third conductive line CL3) for electrical connection with the conductive balls. In some embodiments, the conductive pads 122 are under-ball metallurgy (UBM) patterns for ball mounting, for example. As shown in fig. 1H, a conductive pad 122 is formed on the redistribution layer 120 and electrically connected to the redistribution layer 120. In some embodiments, the material of the conductive pad 122 may include copper, nickel, titanium, tungsten, or an alloy thereof, and may be formed by, for example, an electroplating process. The number of conductive pads 122 is not limited in the present disclosure and may be selected based on the design layout. In some alternative embodiments, the conductive pad 122 may be omitted. In other words, the conductive balls 124 formed in a subsequent step may be directly disposed on the rewiring layer 120.

After forming the conductive pads 122, a plurality of conductive balls 124 are disposed on the conductive pads 122 and on the redistribution layer 120. In some embodiments, the conductive balls 124 may be disposed on the conductive pads 122 by a ball placement process (ball placement process) or a reflow process (reflow process). In some embodiments, the conductive balls 124 are, for example, solder balls or Ball Grid Array (BGA) balls. In some embodiments, the conductive balls 124 are, for example, controlled collapse chip connection (C4) bumps or micro bumps. The present disclosure is not so limited. In some embodiments, the conductive balls 124 are connected to the redistribution layer 120 through conductive pads 122. In some embodiments, some of the conductive balls 124 may be electrically connected to the first semiconductor die 112A through the redistribution layer 120, while some of the conductive balls 124 may be electrically connected to the second semiconductor die 112B through the redistribution layer 120. In addition, in the exemplary embodiment, the number of the conductive balls 124 is not limited to the disclosure, and may be designated and selected based on the number of the conductive pads 122.

Referring to fig. 1I, after the redistribution layer 120 is formed and the conductive balls 124 are placed thereon, the second carrier 101 may be peeled off (in a manner similar to the first carrier 102). In some embodiments, the lift-off layer 103 is further removed, and a dicing process may be performed to cut through the redistribution layer 120 and the insulating seal 118', thereby separating the plurality of package structures PK1 from each other. To this end, the package structure PK1 according to some exemplary embodiments of the present disclosure may be completed.

Fig. 2A-2F are schematic cross-sectional views of various stages in a method of fabricating a package structure according to some other exemplary embodiments of the present disclosure. The embodiment shown in fig. 2A to 2F is similar to the embodiment shown in fig. 1A to 1I, and thus the same reference numerals are used to designate the same or similar components, and detailed description and formation steps thereof will be omitted or simplified herein.

Referring to fig. 2A, in some embodiments, after forming first conductive lines CL1 over seed layer 106, seed layer 106 may be etched or patterned based on the profile of first conductive lines CL 1. In other words, the sidewalls of first conductive lines CL1 are aligned with the sidewalls of seed layer 106. Referring to fig. 2B, after patterning the first conductive line CL1 and the seed layer 106, a first dielectric layer DL1 may be formed to cover the first conductive line CL1 and the seed layer 106. For example, the first conductive line CL1 and the seed layer 106 are embedded in the first dielectric layer DL 1. In some embodiments, the connecting seed layer 108 is formed within the opening of the first dielectric layer DL1 and is electrically connected to the first conductive line CL 1. Subsequently, a connecting element 110 having a body portion 110A and a via portion 110B is formed on the connecting seed layer 108 and in physical contact with the connecting seed layer 108.

Referring to fig. 2C, a first semiconductor die 112A and a second semiconductor die 112B are disposed on the plurality of connection elements 110. The first semiconductor die 112A and the second semiconductor die 112B are disposed on the body portion 110A of the connection element 110 by, for example, flip-chip bonding. The first and second semiconductor dies 112A, 112B are similar to the first and second semiconductor dies 112A, 112B described in fig. 1D, and therefore a detailed description thereof will be omitted herein. In some embodiments, after the first and second semiconductor dies 112A and 112B are disposed onto the connection element 110, the underfill structure 116 is formed on the first dielectric layer DL1 to cover the body portion 110A of the connection element 110 and to partially cover the first and second semiconductor dies 112A and 112B. In some embodiments, an insulating seal 118' is then formed to encapsulate the first semiconductor die 112A, the second semiconductor die 112B, and the underfill structure 116. In some embodiments, the surfaces 118 '-Sx of the insulating seal 118', the backside surface 112A-BS of the first semiconductor die 112A, and the backside surface 112B-BS of the second semiconductor die 112B are coplanar and flush with each other.

Referring to fig. 2D, in a next step, the first carrier 102 is peeled off and separated from the seed layer 106. In some embodiments, the lift-off process includes projecting light, such as laser or UV light, onto the lift-off layer 104 (e.g., LTHC release layer) so that the first carrier 102 can be easily removed with the lift-off layer 104. In some embodiments, after transferring the components on the first carrier 102 to the second carrier 101, the seed layer 106 (a planar seed layer) is exposed on the top surface DL1-TS of the first dielectric layer DL 1. In some embodiments, the seed layer 106 is embedded in the first dielectric layer DL1 and disposed on the top surfaces CL1-TS of the first conductive lines CL 1. In certain embodiments, the top surface 106-TS of the seed layer 106 (the planar seed layer) is coplanar with the top surface DL1-TS of the first dielectric layer DL 1.

Referring to fig. 2E, similarly to the step for forming the rewiring layer 120 described in fig. 1H, a plurality of conductive lines (CL2, CL3), a plurality of vias (V1, V2), a plurality of non-planar seed layers (121A, 121B), and a plurality of dielectric layers (DL2, DL3, DL4) alternately stacked on the seed layer 106 (planar seed layer), on the first conductive line CL1, and over the first dielectric layer DL1 in the first direction D1 (or accumulation direction) are formed. In certain embodiments, the second dielectric layer DL2 is disposed on the seed layer 106 and the first dielectric layer DL1 and is in contact with the seed layer 106 and the first dielectric layer DL 1. In some embodiments, a non-planar seed layer 121A is disposed on the second dielectric layer DL2 and contacts the seed layer 106 (planar seed layer) through the openings of the second dielectric layer DL 2. In some embodiments, the first via V1 is surrounded by the second dielectric layer DL2 and the non-planar seed layer 121A, and is electrically connected to the first conductive line CL1 through the seed layer 106. After the redistribution layer 120 is formed, a plurality of conductive pads 122 and a plurality of conductive balls 124 are disposed on the redistribution layer 120 and electrically connected to the redistribution layer 120.

Referring to fig. 2F, after the redistribution layer 120 is formed and the conductive balls 124 are placed thereon, the second carrier 101 may be peeled off (in a manner similar to the first carrier 102). In some embodiments, the lift-off layer 103 is further removed, and a dicing process may be performed to cut through the redistribution layer 120 and the insulating seal 118', thereby separating the plurality of package structures PK2 from each other. To this end, the package structure PK2 according to some exemplary embodiments of the present disclosure may be completed.

Fig. 3 is a schematic cross-sectional view of a package structure according to some exemplary embodiments of the present disclosure. The package structure PK3 shown in fig. 3 is similar to the package structure PK1 shown in fig. 1I, and thus the same reference numerals are used to refer to the same or similar parts, and detailed description thereof will be omitted herein. The difference between the embodiments is in the design of the conductive pillars of the semiconductor die of package structure PK 3.

As shown in fig. 3, the height PH1 of the first conductive pillars 112A-4 of the first semiconductor die 112A is different than the height PH2 of the second conductive pillars 112B-4 of the second semiconductor die 112B. For example, in some embodiments, the height PH1 of first conductive pillars 112A-4 is greater than the height PH2 of second conductive pillars 112B-4. However, the overall height of the first semiconductor die 112A is substantially equal to the overall height of the second semiconductor die 112B. Similar to the above-described embodiments, since the semiconductor dies (112A, 112B) are bonded onto the plurality of connection elements 110 at the front side of the insulating seal 118 ', and a grinding or planarization process is performed on the insulating seal 118 ' and the back sides of the semiconductor dies (112A, 112B), cracks in the insulating seal 118 ' and cracks in the redistribution layer 120 can be reduced.

Fig. 4 is a schematic cross-sectional view of a package structure according to some other exemplary embodiments of the present disclosure. The package structure PK4 shown in fig. 4 is similar to the package structure PK3 shown in fig. 3, and thus the same reference numerals are used to refer to the same or similar parts, and detailed description thereof will be omitted herein. The difference between the embodiments is that a protective layer is also provided in the package structure PK 4.

As shown in fig. 4, the first semiconductor die 112A may include a protective layer 112A-5 surrounding the first conductive pillars 112A-4. In some embodiments, the protective layer 112A-5 is formed on the passivation layer 112A-3 or the post passivation layer and covers the sidewalls of the first conductive pillars 112A-4. In a similar manner, the second semiconductor die 112B may include a protective layer 112B-5 surrounding the second conductive pillars 112B-4. In some embodiments, the protection layer 112B-5 is formed on the passivation layer 112B-3 or the post-passivation layer and covers the sidewalls of the second conductive pillars 112B-4. Although both the first semiconductor die 112A and the second semiconductor die 112B are shown in fig. 4 as including protective layers (112A-5 and 112B-5), the disclosure is not so limited. In an alternative embodiment, only one of the first semiconductor die 112A or the second semiconductor die 112B includes a protective layer (112A-5 or 112B-5). Similar to the above-described embodiments, since the semiconductor dies (112A, 112B) are bonded onto the plurality of connection elements 110 located at the front side of the insulating seal 118 ', and a grinding or planarization process is performed on the insulating seal 118 ' and the back sides of the semiconductor dies (112A, 112B), cracks in the insulating seal 118 ' and cracks in the redistribution layer 120 can be reduced.

Fig. 5 is a schematic cross-sectional view of a package structure according to some other exemplary embodiments of the present disclosure. The package structure PK5 shown in fig. 5 is similar to the package structure PK1 shown in fig. 1I, and thus the same reference numerals are used to refer to the same or similar parts, and detailed description thereof will be omitted herein. The difference between the embodiments is that an insulator penetration hole is also provided in the encapsulation structure PK 5.

As shown in fig. 5, in some embodiments, package structure PK5 further includes an insulator through-hole 130 surrounding first semiconductor die 112A and second semiconductor die 112B. In some embodiments, the insulator through-hole 130 may include a body portion 130A surrounded by the insulator seal 118' and a via portion 130B surrounded by the first dielectric layer DL 1.

In one embodiment, the formation of the insulator through-hole 130 includes forming a mask pattern (not shown) having an opening, then forming a metal material (not shown) filling the opening by electroplating or deposition, and removing the mask pattern to form the insulator through-hole 130 on the first dielectric layer DL 1. In some embodiments, the insulator penetration holes 130 are filled into the via openings exposing the first conductive lines CL1 of the redistribution layer 120, so that the insulator penetration holes 130 may be electrically connected to the redistribution layer 120. In one embodiment, the material of the insulator through-hole 130 may include a metal material, such as copper or a copper alloy, etc. However, the present disclosure is not so limited.

In an alternative embodiment, the insulator penetration holes 130 may be formed by: forming a seed layer on first dielectric layer DL1 (along with the formation of connecting seed layer 108); forming a mask pattern having an opening exposing a portion of the seed layer; forming a metal material on the exposed portion of the seed layer by plating to form an insulator penetration hole 130; removing the mask pattern; the portion of the seed layer exposed by the insulator perforations 130 is then removed. For example, the seed layer may be a titanium/copper composite layer. For simplicity, only two insulator perforations 130 are shown in fig. 5. It should be noted, however, that the number of insulator perforations 130 is not so limited and may be selected based on requirements.

As further shown in fig. 5, in some embodiments, a dielectric layer 132 is disposed on a backside surface of the insulating seal 118' opposite where the redistribution layer 120 is located. In some embodiments, the dielectric layer 132 has an opening exposing the body portion 130A of the insulator through-hole 130, and the conductive terminal 134 is further disposed in the opening of the dielectric layer 132 and connected to the insulator through-hole 130. To this end, the package structure PK5 with double-sided terminals is completed.

Fig. 6A-6F are schematic cross-sectional views of various stages in a method of fabricating a package structure according to some other exemplary embodiments of the present disclosure. The embodiment shown in fig. 6A to 6F is similar to the embodiment shown in fig. 1A to 1I, and thus the same reference numerals are used to refer to the same or similar parts, and detailed description thereof will be omitted or simplified herein.

Referring to fig. 6A, a first carrier 102 having a release layer 104 coated thereon is provided. In some embodiments, the first semiconductor die 112A and the second semiconductor die 112B are picked and placed on the exfoliation layer 104. In some embodiments, the first semiconductor die 112A and the second semiconductor die 112B are attached to the lift-off layer 104 by a die attach film (not shown). The first and second semiconductor dies 112A, 112B are similar to the first and second semiconductor dies 112A, 112B described in fig. 1D. However, in an exemplary embodiment, the first semiconductor die 112A also includes a protective layer 112A-5 covering the first conductive pillars 112A-4, while the second semiconductor die 112B is free of any protective layer and includes conductive bumps 114 on each of the second conductive pillars 112B-4. In some embodiments, the overall height of the second semiconductor die 112B is less than the overall height of the first semiconductor die 112A.

Referring to fig. 6B, in a next step, a plurality of connection posts 204 on the support structure 202 are provided. In some embodiments, the connection post 204 is bonded and electrically connected with the second conductive pillar 112B-4 of the second semiconductor die 112B by the conductive bump 114. In an exemplary embodiment, the material of the connection stud 204 may be similar to the material of the second conductive post 112B-4. Furthermore, the support structure 202 may be a silicon support, although the disclosure is not limited thereto. In some other embodiments, the support structure 202 may be any type of support structure for holding the connection post 204, which may be sacrificially removed in a subsequent step.

Referring to fig. 6C, an underfill structure 116 is formed on the peeling layer 104 to cover the second conductive pillars 112B-4, the connection pillars 204 and the conductive bumps 114. In some embodiments, the underfill structure 116 fills in the space between the first semiconductor die 112A and the second semiconductor die 112B to separate the first semiconductor die 112A from the second semiconductor die 112B. In certain embodiments, the underfill structure 116 also partially covers the support structure 202. After forming the underfill structure 116, an insulating material 118 is formed on the exfoliation layer 104 to encapsulate the first semiconductor die 112A, the second semiconductor die 112B and surround the plurality of connection posts 204.

Referring to fig. 6D, the insulating material 118 may be partially removed to expose the connection stud 204 and the first semiconductor die 112A. In some embodiments, the insulating material 118 is ground or polished by a planarization step. The planarization step is performed, for example, by a mechanical grinding process and/or a Chemical Mechanical Polishing (CMP) process, until the top surfaces 204-TS of the connection pillars 204 and the top surfaces 112A-TS of the first conductive pillars 112A-4 are exposed. In some embodiments, the support structure 202 is completely removed during the planarization step. In some embodiments, the connection post 204 and the first conductive post 112A-4 may also be ground/polished.

As shown in fig. 6D, the insulating material 118 is polished to form an insulating seal 118'. In certain embodiments, the top surfaces 118-TS of the insulating seal 118', the top surfaces 116-TS of the underfill structure 116, the top surfaces 204-TS of the connection posts 204, and the top surfaces 112A-TS of the first conductive posts 112A-4 are coplanar and flush with one another. In some embodiments, a cleaning step may be performed after a mechanical grinding or Chemical Mechanical Polishing (CMP) step, if desired. For example, a cleaning step is performed to clean and remove residues resulting from the planarization step. However, the present disclosure is not limited thereto, and the planarization step may be performed by any other suitable method.

Referring to fig. 6E, after forming the insulating seal 118 ', a redistribution layer 120 is formed over the insulating seal 118', and the redistribution layer 120 is electrically connected to the first semiconductor die 112A and the second semiconductor die 112B. In some embodiments, the formation of the redistribution layer 120 includes forming a plurality of conductive lines CLx (including CL1, CL2, and CL3), a plurality of vias Vx (including V1, V2, and V3), a plurality of non-planar seed layers (including 121A, 121B, and 121C), and a plurality of dielectric layers DLx (including DL1, DL2, DL3, and DL4) alternately stacked over the insulating seal 118'. In some embodiments, the first via V1 is electrically connected to the connection post 204 and the first conductive post 112A-4 through the non-planar seed layer 121A.

After forming the redistribution layer 120, a plurality of conductive pads 122 may be disposed on the exposed top surfaces of the topmost conductive line CLx (third conductive line CL3) for electrical connection with the conductive balls. In some embodiments, the conductive pad 122 is, for example, an Under Ball Metal (UBM) pattern for ball mounting. As shown in fig. 6E, a conductive pad 122 is formed on the redistribution layer 120 and electrically connected to the redistribution layer 120. The number of conductive pads 122 is not limited in the present disclosure and may be selected based on the design layout. Thereafter, a plurality of conductive balls 124 are disposed on the conductive pads 122 and on the redistribution layer 120. In some embodiments, the conductive balls 124 may be disposed on the conductive pads 122 by a ball-mounting process or a reflow process. In some embodiments, conductive balls 124 are, for example, solder balls or Ball Grid Array (BGA) balls. In some embodiments, the conductive balls 124 are, for example, controlled collapse chip connection (C4) bumps or microbumps. The present disclosure is not so limited.

Referring to fig. 6F, after the redistribution layer 120 is formed and the conductive balls 124 are placed thereon, the first carrier 102 may be peeled off. In some embodiments, the exfoliation layer 104 is further removed, and a dicing process may be performed to cut through the redistribution layer 120 and the insulating seal 118', thereby separating the plurality of package structures PK6 from one another. To this end, the package structure PK6 according to some other exemplary embodiments of the present disclosure may be completed.

Fig. 7A-7H are schematic cross-sectional views of various stages in a method of fabricating a package structure according to some other example embodiments of the present disclosure. The embodiment shown in fig. 7A to 7H is similar to the embodiment shown in fig. 6A to 6F, and thus the same reference numerals are used to designate the same or similar components, and detailed description thereof will be omitted or simplified herein.

The steps of providing a semiconductor die having a connection stud 204 disposed thereon are described with reference to fig. 7A-7C. Referring to fig. 7A, in some embodiments, a carrier CR1 having a release layer DB coated thereon is provided. The carrier CR1 and release layer DB may be similar to the first carrier 102 and release layer 104 described in the embodiments above. In some embodiments, a plurality of connection posts 204 are formed on the release layer DB and above the carrier CR 1.

Referring to fig. 7B, after the connection studs 204 are formed, the semiconductor dies 112C and 112D are disposed on the connection studs 204 by flip chip bonding. The semiconductor dies 112C and 112D are similar to the first semiconductor die 112A or the second semiconductor die 112B described in the above embodiments, and detailed description thereof will be omitted herein. Briefly, each of the semiconductor dies 112C and 112D includes a semiconductor substrate (112C-1/112D-1), a plurality of conductive pads (112C-2/112D-2), a passivation layer (112C-3/112D-3), and a plurality of conductive pillars (112C-4/112D-4). In some embodiments, conductive pillars (112C-4/112D-4) of semiconductor die 112C and 112D are bonded to connection pillar 204 by conductive bump 114.

Referring to fig. 7C, the structure shown in fig. 1B is inverted and applied to a strip 301 (e.g., a slit strip) supported by a frame 302. As shown in fig. 7C, carrier CR1 is peeled away and separated from semiconductor die 112C and 112D. In some embodiments, the lift-off process includes projecting light, such as laser or UV light, on the lift-off layer DB (e.g., LTHC release layer) so that the carrier CR1 can be easily removed along with the lift-off layer DB. During the peeling step, the tape 301 is used to secure the semiconductor die 112C and 112D prior to peeling the carrier CR1 and the peeling layer DB. After the lift-off process, semiconductor die 112C and 112D are fabricated with connection studs 204 disposed thereon.

Referring to fig. 7D, a first semiconductor die 112A and the semiconductor die 112C fabricated in fig. 7C are disposed on the exfoliation layer 104 and over the carrier 102. In an exemplary embodiment, the first semiconductor die 112A further includes a protective layer 112A-5 covering the first conductive pillars 112A-4, and the semiconductor die 112C further includes conductive bumps 114 and connection posts 204 on the conductive bumps 114. Referring to fig. 7E, in a subsequent step, an underfill structure 116 is formed on the peeling layer 104 to cover the conductive pillars 112C-4, the connection pillars 204 and the conductive bumps 114. In some embodiments, the underfill structure 116 fills in the space between the first semiconductor die 112A and the semiconductor die 112C to separate the first semiconductor die 112A from the semiconductor die 112C. After forming the underfill structure 116, an insulating material 118 is formed on the exfoliation layer 104 to encapsulate the first semiconductor die 112A, the semiconductor die 112C and surround the plurality of connection posts 204.

Referring to fig. 7F, the insulating material 118 may be partially removed to expose the connection stud 204 and the first semiconductor die 112A. In some embodiments, the insulating material 118 is ground or polished by a planarization step. The planarization step is performed, for example, by a mechanical grinding process and/or a Chemical Mechanical Polishing (CMP) process, until the top surfaces 204-TS of the connection pillars 204 and the top surfaces 112A-TS of the first conductive pillars 112A-4 are exposed. In some embodiments, the insulating material 118 is polished to form an insulating seal 118'. In certain embodiments, the top surfaces 118-TS of the insulating seal 118', the top surfaces 116-TS of the underfill structure 116, the top surfaces 204-TS of the connection posts 204, and the top surfaces 112A-TS of the first conductive posts 112A-4 are coplanar and flush with one another.

Referring to fig. 7G, after the insulating seal 118 'is formed, a rewiring layer 120 is formed over the insulating seal 118' in the same manner as described in fig. 6E. In some embodiments, redistribution layer 120 is electrically connected to first semiconductor die 112A and semiconductor die 112C. In some embodiments, redistribution layer 120 is electrically connected to semiconductor die 112C through connection stud 204. After the redistribution layer 120 is formed, a plurality of conductive pads 122 may be disposed on the redistribution layer 120 and electrically connected to the redistribution layer 120. Thereafter, a plurality of conductive balls 124 are disposed on the conductive pads 122 and on the redistribution layer 120. In some embodiments, the conductive balls 124 may be disposed on the conductive pads 122 by a ball-mounting process or a reflow process. In some embodiments, conductive balls 124 are electrically connected to first semiconductor die 112A and/or semiconductor die 112C.

Referring to fig. 7H, after the redistribution layer 120 is formed and the conductive balls 124 are placed thereon, the first carrier 102 may be peeled off. In some embodiments, the exfoliation layer 104 is further removed, and a dicing process may be performed to cut through the redistribution layer 120 and the insulating seal 118', thereby separating the plurality of package structures PK7 from one another. To this end, the package structure PK7 according to some other exemplary embodiments of the present disclosure may be completed.

Fig. 8 is a schematic cross-sectional view of a package structure according to some other example embodiments of the present disclosure. The package structure PK8 shown in fig. 8 is similar to the package structure PK7 shown in fig. 7H, and thus the same reference numerals are used to refer to the same or similar parts, and detailed description thereof will be omitted herein. The difference between the embodiments is that an insulator penetration hole is also provided in the encapsulation structure PK 8.

As shown in fig. 8, in some embodiments, package structure PK8 further includes an insulator through-hole 130 surrounding first semiconductor die 112A and semiconductor die 112C. In some embodiments, the insulator perforations 130 are embedded in the insulator seal 118' and electrically connected to the redistribution layer 120. In one embodiment, the material of the insulator through-hole 130 may include a metal material, such as copper or a copper alloy, etc. However, the present disclosure is not so limited.

Further, in some embodiments, a dielectric layer 132 is disposed on a backside surface of the insulating seal 118' opposite where the redistribution layer 120 is located. In some embodiments, the dielectric layer 132 has openings exposing the insulator through-holes 130, and the conductive terminals 134 are further disposed in the openings of the dielectric layer 132 and connected to the insulator through-holes 130. To this end, the package structure PK8 with double-sided terminals is completed.

In the above-described embodiment, since the semiconductor die is bonded to the plurality of connection elements located at the front side of the insulating seal, and a grinding or planarization process is performed on the insulating seal and the back side of the semiconductor die, cracks in the insulating seal 118' and cracks in the redistribution layer 120 can be further reduced. In addition, molding and grinding on the conductive pillars of the semiconductor die may be reduced because multiple connection pillars are used to compensate for die height variations. Therefore, cracks in the molding compound (encapsulant) and cracks in the rewiring layer can be further reduced. In summary, semiconductor dies with varying thicknesses can be efficiently integrated in a package structure, and a package structure with better reliability can be fabricated.

According to some embodiments of the present disclosure, a package structure includes a plurality of semiconductor dies, an insulating seal, a redistribution layer, and a plurality of connection elements. The insulating seal encapsulates the plurality of semiconductor dies. The redistribution layer is disposed on the insulating seal along a stacking direction and electrically connected to the plurality of semiconductor dies, wherein the redistribution layer includes a plurality of conductive lines, a plurality of vias, and a plurality of dielectric layers that are alternately stacked, and a lateral dimension of the plurality of vias increases along the stacking direction. The connecting element is disposed between the redistribution layer and the semiconductor die, wherein the connecting element includes a body portion bonded to the semiconductor die and a via portion bonded to the redistribution layer, wherein a lateral dimension of the via portion decreases along the stacking direction.

In some embodiments, the body portions of the plurality of connecting elements are surrounded by the insulating seal and the via portions of the plurality of connecting elements are surrounded by a bottommost dielectric layer of the plurality of dielectric layers. In some embodiments, the rerouting layer comprises: a first dielectric layer of the plurality of dielectric layers surrounding the via portions of the plurality of connection elements; and a first conductive line of the plurality of conductive lines embedded in the first dielectric layer, wherein the first conductive line has a top surface and a bottom surface opposite the top surface, the bottom surface is engaged with the through-hole portions of the plurality of connection elements and is in contact with the first dielectric layer, and the top surface is coplanar with a surface of the first dielectric layer. In some embodiments, the rerouting layer further comprises: a first dielectric layer of the plurality of dielectric layers surrounding the via portions of the plurality of connection elements; and a first conductive line of the plurality of conductive lines embedded in the first dielectric layer, wherein the first conductive line has a top surface and a bottom surface opposite the top surface, the bottom surface engaging the through-hole portions of the plurality of connection elements and contacting the first dielectric layer; a planar seed layer embedded in the first dielectric layer and disposed on the top surface of the first conductive line, wherein a surface of the planar seed layer is coplanar with a surface of the first dielectric layer; a second dielectric layer of the plurality of dielectric layers disposed on the planar seed layer and over the first dielectric layer; a non-planar seed layer disposed on the second dielectric layer and in contact with the planar seed layer; and a first via of the plurality of vias surrounded by the second dielectric layer and the non-planar seed layer. In some embodiments, the package structure further comprises an underfill structure embedded in the insulating seal, wherein the underfill structure covers the body portions of the plurality of connection elements and partially covers the plurality of semiconductor dies. In some embodiments, the width of the underfill structure increases along the stacking direction. In some embodiments, each of the plurality of semiconductor dies includes a plurality of conductive pillars, and the plurality of conductive pillars are electrically connected to the body portions of the plurality of connection elements.

According to some other embodiments of the present disclosure, a package structure includes a first semiconductor die, a second semiconductor die, an underfill structure, an insulating seal, a redistribution layer, and a plurality of connection elements. The first semiconductor die has a plurality of first conductive pillars. The second semiconductor die has a plurality of second conductive pillars. The underfill structure covers the first conductive pillars and the second conductive pillars. The insulating seal encapsulates the first semiconductor die, the second semiconductor die, and the underfill structure. The redistribution layer is disposed on the insulating seal and on the underfill structure, wherein the redistribution layer includes a plurality of conductive lines, a plurality of via holes, and a plurality of dielectric layers stacked alternately. The plurality of connection elements electrically connect the redistribution layer to the plurality of first conductive pillars of the first semiconductor die and the plurality of second conductive pillars of the second semiconductor die, wherein a portion of the plurality of connection elements are surrounded by the underfill structure and another portion of the plurality of connection elements are surrounded by a first dielectric layer of the plurality of dielectric layers.

In some embodiments, the height of the plurality of first conductive pillars is different from the height of the plurality of second conductive pillars. In some embodiments, the package structure further includes a connection seed layer between the plurality of connection elements and the redistribution layer. In some embodiments, the rerouting layer further comprises: a first conductive line of the plurality of conductive lines embedded in the first dielectric layer and electrically connected to the plurality of connection elements; and a planar seed layer embedded in the first dielectric layer and disposed on a top surface of the first conductive line, wherein a surface of the planar seed layer is coplanar with a surface of the first dielectric layer. In some embodiments, the rerouting layer further comprises: a second dielectric layer of the plurality of dielectric layers disposed on the planar seed layer and over the first dielectric layer; a non-planar seed layer disposed on the second dielectric layer and in contact with the planar seed layer; and a first via of the plurality of vias surrounded by the second dielectric layer and the non-planar seed layer. In some embodiments, the package structure further includes a plurality of conductive bumps interposed between the plurality of connection elements and the plurality of first conductive pillars or interposed between the plurality of connection elements and the plurality of second conductive pillars. In some embodiments, at least one of the first semiconductor die or the second semiconductor die has a protective layer surrounding the plurality of first conductive pillars or surrounding the plurality of second conductive pillars, and the protective layer is covered by the underfill structure.

According to some other embodiments of the present disclosure, a method of fabricating a package structure is described. The method comprises the following steps. A first carrier is provided. A first conductive line is formed on the first carrier. Forming a first dielectric layer to cover the first conductive line, wherein the first dielectric layer has a plurality of openings exposing a surface of the first conductive line. Forming a plurality of connection elements on the first dielectric layer and in the plurality of openings, wherein the plurality of connection elements comprise a body portion and a via portion, the via portion is joined with the first conductive line, and a lateral dimension of the via portion decreases along a first direction of the package structure. A plurality of semiconductor dies are disposed on the body portions of the plurality of connection elements. An insulating seal is formed to encapsulate the plurality of semiconductor dies and the plurality of connection elements. Peeling the first carrier and transferring the packaging structure to a second carrier. Forming a plurality of conductive lines, a plurality of vias, and a plurality of dielectric layers alternately stacked over the first conductive lines and the first dielectric layers to constitute a redistribution layer, wherein lateral dimensions of the plurality of vias increase along the first direction of the package structure.

In some embodiments, after forming the insulating seal, a planarization process is performed on the insulating seal and the backside of the plurality of semiconductor dies to form a coplanar surface. In some embodiments, the method for manufacturing a package structure further includes: forming a planar seed layer on the first carrier prior to forming the first conductive line; forming the first conductive line on the planar seed layer over the first carrier; and forming the first dielectric layer overlying the first conductive line and the planar seed layer. In some embodiments, the planar seed layer is completely removed after transferring the encapsulation structure onto the second carrier. In some embodiments, the plurality of vias are formed to electrically connect to the planar seed layer. In some embodiments, the method for manufacturing a package structure further includes: forming an underfill structure that covers the body portions of the plurality of connection elements and partially covers the plurality of semiconductor dies; and forming the insulating seal to encapsulate the underfill structure, the plurality of semiconductor dies, and the plurality of connection elements.

According to yet another embodiment of the present disclosure, a package structure includes a first semiconductor die, a second semiconductor die, a plurality of connection posts, an insulating seal, and a redistribution layer. The first semiconductor die has a plurality of first conductive pillars. The second semiconductor die has a plurality of second conductive pillars, wherein a height of the second semiconductor die is less than a height of the first semiconductor die. The plurality of connection posts are bonded with the plurality of second conductive posts of the second semiconductor die, wherein top surfaces of the plurality of connection posts are coplanar with top surfaces of the plurality of first conductive posts. The insulating seal encapsulates the first semiconductor die, the second semiconductor die, and the plurality of connection pillars. The redistribution layer is disposed on the insulating seal and electrically connected to the first conductive posts and the connection posts.

The foregoing has outlined 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.