阅读说明：本技术 堆栈式硅封装组件的扇出集成 (Fan-out integration of stacked silicon package assembly ) 是由 J·S·甘地 S·拉玛林加姆 于 2020-11-03 设计创作，主要内容包括：本公开的实施例涉及堆栈式硅封装组件的扇出集成。提供了一种芯片封装组件及其制造方法,其利用模制化合物中的多个柱来提高抗分层性。在一个示例中,提供了一种芯片封装组件,该芯片封装组件包括第一集成电路(IC)管芯、衬底、再分布层、模制化合物、以及多个柱。再分布层提供第一IC管芯的电路系统与衬底的电路系统之间的电连接。模制化合物被设置为与第一IC管芯接触并且通过再分布层与衬底隔开。多个柱被布置在模制化合物中并且与第一IC管芯横向隔开。多个接线柱没有电连接到第一IC管芯的电路系统。(Embodiments of the present disclosure relate to fan-out integration of stacked silicon package components. A chip package assembly and a method of manufacturing the same are provided that utilize a plurality of pillars in a molding compound to improve delamination resistance. In one example, a chip package assembly is provided that includes a first Integrated Circuit (IC) die, a substrate, a redistribution layer, a molding compound, and a plurality of pillars. The redistribution layer provides electrical connections between circuitry of the first IC die and circuitry of the substrate. The molding compound is disposed in contact with the first IC die and is separated from the substrate by a redistribution layer. A plurality of pillars is disposed in the molding compound and is laterally spaced from the first IC die. The plurality of posts are not electrically connected to circuitry of the first IC die.)

1. A chip package assembly comprising:

a first Integrated Circuit (IC) die;

a substrate;

a redistribution layer providing electrical connections between circuitry of the first IC die and circuitry of the substrate;

a molding compound disposed in contact with the first IC die and separated from the substrate by the redistribution layer; and

a plurality of pillars disposed in the molding compound and laterally spaced from the first IC die, the plurality of pillars not electrically connected to the circuitry of the first IC die.

2. The chip package assembly of claim 1, wherein bottom surfaces of the plurality of pillars and bottom surfaces of the molding compound contact the redistribution layer.

3. The chip package assembly of claim 2, wherein the bottom surfaces of the plurality of pillars and the bottom surface of the mold compound are coplanar.

4. The chip package assembly of claim 1, wherein the plurality of pillars are made of a metal-containing material.

5. The chip package assembly of claim 1, further comprising:

a second IC die disposed in contact with a molding compound and laterally spaced from the first IC die, the second IC die being spaced from the substrate by the redistribution layer, wherein at least some of the plurality of pillars are disposed between the first IC die and the second IC die.

6. The chip package assembly of claim 5, wherein at least some of the plurality of pillars are disposed on a side of the first IC die opposite the second IC die.

7. The chip package assembly of claim 5, wherein the plurality of pillars are electrically floating with respect to the circuitry of the first IC die and circuitry of the second IC die.

8. The chip package assembly of claim 7, wherein top and bottom surfaces of the plurality of pillars are coplanar.

9. The chip package assembly of claim 5, further comprising:

a memory die stacked on the second IC die, wherein the first IC die is configured as a logic die.

10. A chip package assembly comprising:

a substrate;

a redistribution layer having circuitry electrically coupled to the circuitry of the substrate via solder connections;

a first Integrated Circuit (IC) die;

a second Integrated Circuit (IC) die;

a molding compound disposed in contact with the first IC die and separated from the substrate by the redistribution layer; and

a first plurality of pillars disposed in the mold compound between the first IC die and the second IC die, the first plurality of pillars being separated from the substrate by the redistribution layer.

11. The chip package assembly of claim 10, wherein bottom surfaces of the first plurality of pillars and bottom surfaces of the mold compound are coplanar and contact the redistribution layer.

12. The chip package assembly of claim 10, wherein the first plurality of pillars is made of a metal-containing material.

13. The chip package assembly of claim 10, further comprising:

a second plurality of pillars disposed on a side of the first IC die opposite the second IC die.

14. The chip package assembly of claim 10, wherein the plurality of pillars are electrically floating with respect to circuitry of the first IC die and circuitry of the second IC die.

15. The chip package assembly of claim 10, further comprising:

a memory die stacked on the second IC die, wherein the first IC die is configured as a logic die.

16. A method of fabricating a chip package assembly, the method comprising:

mounting a first Integrated Circuit (IC) die to a carrier;

mounting a second IC die to the carrier;

filling a gap formed between the first IC die and the second IC with a molding compound, the molding compound disposed around a first pillar, the first pillar disposed in the gap;

removing a portion of the molding compound to expose electrical contact pads of the first IC die and the second IC die; and

forming a redistribution layer over the molding compound and the first and second IC dies, the redistribution layer having circuitry electrically connected to the circuitry of the first and second IC dies.

17. The method of claim 16, further comprising:

removing the carrier.

18. The method of claim 16, further comprising:

electrically and mechanically coupling the redistribution layer to a substrate via a solder connection.

19. The method of claim 16, wherein mounting the first IC die further comprises: mounting a logic die to the carrier; and

wherein mounting the second IC die further comprises: a memory stack is mounted to the carrier.

20. The method of claim 16, wherein removing the portion of the mold compound to expose electrical contacts of the first IC die and the second IC die further comprises:

grinding the molding compound.

Technical Field

Various embodiments of the present invention generally relate to a chip package assembly, and in particular to a chip package assembly including a plurality of pillars disposed in a mold compound, the pillars laterally spaced from at least one Integrated Circuit (IC) die, the pillars configured to reduce the likelihood of mold compound delamination or cracking during fabrication of the chip package assembly.

Background

Electronic devices such as tablet computers, copiers, digital cameras, smart phones, control systems, and automated teller machines, etc., often employ electronic components utilizing chip package assemblies to increase functionality and increase component density. Conventional die packaging schemes typically utilize a package substrate, typically in combination with a through-silicon via (TSV) interposer substrate, to enable multiple Integrated Circuit (IC) dies to be mounted to a single package substrate. The IC die may include memory, logic, or other IC devices.

In many next generation chip package assemblies, fan-out, such as redistribution layers, are used to connect IC dies to substrates on which the IC dies are mounted. IC dies are typically disposed in a molding compound to provide improved structural integrity to the chip package assembly. However, cracks in the mold compound and/or delamination of the mold compound from the IC die often propagate into the fan-out, which can cause conductors (i.e., electrical traces) within the fan-out to break or deteriorate. Breakage and/or damage to conductors within the fan-out can lead to reduced performance, reduced service life, and even equipment failure.

Accordingly, there is a need for a chip package assembly having resistance to damage and/or breakage of conductors within a fan-out disposed between an IC die and a substrate on which the IC die is mounted.

Disclosure of Invention

A chip package assembly and method of manufacturing the same are provided that inhibits damage and/or breakage to conductors within a fan-out (i.e., redistribution layer) disposed between at least one Integrated Circuit (IC) die and a substrate such as an interposer substrate or package substrate. In one example, robust protection of fan-out is provided by creating coplanar contacts across adjacent dies using a non-abrasive process prior to fabricating a redistribution layer over the contacts. In another example, the plurality of pillars in the molding compound act to inhibit delamination and/or cracking of the molding compound, thereby reducing the likelihood that defects will propagate from the molding compound to the redistribution layer, wherein the defects may damage and/or break conductors within the redistribution layer.

In one example, a chip package assembly is provided that includes a first Integrated Circuit (IC) die, a substrate, a redistribution layer, a molding compound, and a plurality of pillars. The redistribution layer provides electrical connections between circuitry of the first IC die and circuitry of the substrate. The molding compound is disposed in contact with the first IC die and is separated from the substrate by a redistribution layer. A plurality of pillars is disposed in the molding compound and laterally spaced from the first IC die. The plurality of pillars are not electrically connected to circuitry of the first IC die.

In another example, a chip package assembly is provided that includes a first Integrated Circuit (IC) die, a second IC die, a substrate, a redistribution layer, a molding compound, and a plurality of posts. The redistribution layer has circuitry that is electrically coupled to circuitry of the substrate via solder connections. The molding compound is disposed in contact with the first IC die and is separated from the substrate by a redistribution layer. The first plurality of pillars is disposed in a mold compound between the first IC and the second IC. The first plurality of pillars is separated from the substrate by a redistribution layer.

In another example, there is provided a method of manufacturing a chip package assembly, the method comprising: mounting a first Integrated Circuit (IC) die to a carrier; mounting a second IC die to a carrier; filling a gap formed between the first IC die and the second IC with a molding compound, the molding compound being disposed around a first pillar, the first pillar being disposed in the gap; removing a portion of the molding compound to expose electrical contacts of the first IC die and the second IC; and forming a redistribution layer over the molding compound and the first and second IC dies, the redistribution layer having circuitry electrically connected to the circuitry of the first and second IC dies.

Drawings

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

Fig. 1 is a schematic cross-sectional view of a chip package assembly with a plurality of pillars disposed around an Integrated Circuit (IC) die.

Fig. 2 is a partial cross-sectional view of the chip package assembly of fig. 1 illustrating pillars disposed adjacent a redistribution layer of the chip package assembly.

Fig. 3 is a schematic top view of the chip package assembly of fig. 1 showing an exemplary geometric arrangement of pillars disposed around the IC die.

Fig. 4 is a flow diagram of a method of manufacturing a chip package assembly with pillars configured to enhance reliability of circuitry within a redistribution layer.

Fig. 5A-5F are schematic cross-sectional views of a chip package assembly at different stages of the method of fig. 4.

Fig. 6 is a flow diagram of a method of manufacturing a chip package assembly configured to enhance reliability of circuitry within a redistribution layer.

Fig. 7A-7G are schematic cross-sectional views of a chip package assembly at different stages of the method of fig. 6.

Fig. 8 is a flow diagram of another method of fabricating a chip package assembly configured to enhance reliability of circuitry within a redistribution layer.

Fig. 9A-9I are schematic cross-sectional views of a chip package assembly at different stages of the method of fig. 6.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements of one embodiment may be beneficially incorporated in other embodiments.

Detailed Description

A chip package assembly and method of manufacturing the same are provided that inhibits damage and/or breakage to conductors disposed within a fan-out (interchangeably referred to as a "redistribution layer") between at least one Integrated Circuit (IC) die and a substrate such as an interposer substrate or package substrate. In one example, a no-grind process is used to create coplanar contact pads on adjacent IC dies without grinding conductive posts extending from the IC dies and the molding compound. Since grinding is a common cause of crack generation and delamination in molding compounds, eliminating grinding operations in some examples greatly enhances the probability of such defects in the molding compound, and thus greatly reduces the probability of such defects causing cracks to propagate into the fan-out where the conductor may be damaged or broken. In other examples, a plurality of pillars disposed in a mold compound surrounding at least one Integrated Circuit (IC) die are used to inhibit crack generation and delamination in the mold compound even during grinding used to expose contact pads of the IC die.

The chip package assembly described herein includes at least one Integrated Circuit (IC) die disposed in a mold compound and mounted on a substrate. A redistribution layer is disposed between the IC die and the substrate. The redistribution layer is electrically and mechanically coupled to the substrate via a solder connection. The redistribution layer provides signal, ground, and power transmission paths (i.e., circuitry) between the IC die and the substrate. The substrate may be a package substrate or an interposer substrate. When utilized, the pillars do not extend through the IC die and are located laterally outward of the IC die. These pillars significantly improve the mechanical properties of the molding compound, thereby greatly increasing the resistance of the molding compound to cracking or delamination (i.e., peeling) from the IC die during removal of a portion of the molding compound to expose contact pads or conductors of the IC die for electrical connection to the fanout circuitry fabricated in the redistribution layer. Since the molding compound as described above is less likely to occur or to crack or delaminate, such defects are less likely to propagate into the redistribution layer, where one or more wires of the redistribution layer may be damaged, resulting in reduced performance or even failure of the chip package assembly.

Other examples and techniques for preventing damage to circuitry of fan-outs fabricated in redistribution layers are disclosed herein, which may alternatively be without posts within the molding compound. These techniques utilize etching recesses in the molding compound to expose the die contact pads. The dielectric material is then patterned on the molding compound while still exposing the die contact pads. A conductive material is deposited into the recess and connected with the exposed contact pads of the IC die. The conductive material is coplanar with the bottom surface of the dielectric material such that the redistribution layer may be fabricated directly without grinding or inducing other mechanical stresses in the polymer material disposed adjacent to the redistribution layer. As a result, defects in the polymer material disposed adjacent to the redistribution layer are highly unlikely to propagate into the redistribution layer, where one or more wires of the redistribution layer may be damaged, resulting in performance degradation and even failure of the chip package assembly.

Thus, enhancing the resistance of the molding compound and other polymer layers adjacent to the redistribution layer to cracking and/or delamination greatly improves the prevention of crack propagation into the fan-out, which can result in conductor damage or breakage within the fan-out. Therefore, the reliability and performance of the chip package assembly are significantly improved.

Turning now to fig. 1, a schematic cross-sectional view of a chip package assembly 100 is schematically illustrated, the chip package assembly 100 having a plurality of pillars 110 adjacent to Integrated Circuit (IC) dies 106, 126, the plurality of pillars 110 disposed in a molding compound 112. The chip package assembly 100 also includes a redistribution layer (RDL)102, an interposer substrate 104, and a package substrate 108. The redistribution layer 102 is disposed between the IC die 106 and the interposer substrate 104, and is also in contact with the molding compound 112.

Although two IC dies 106, 126 are shown in fig. 1 as being laterally spaced from each other, the total number of IC dies may range from one to as many as possible of the number of dies that may fit within the chip package assembly 100. Additionally, although fig. 1 illustrates a single IC die 106, the IC die 106 may be a bottom die of a stack of IC dies. Still further, although the IC die 126 illustrated in fig. 1 is shown as a stack of IC dies 126, the stack of IC dies 126 may alternatively be replaced by a single IC die 126. Examples of IC dies 106, 126 that may be used in the chip package assembly 100 include, but are not limited to, programmable logic devices such as Field Programmable Gate Arrays (FPGAs), memory devices such as High Bandwidth Memories (HBMs), optical devices, processors, or other IC logic structures. One or more of the IC dies 106 may optionally include optical devices, such as photodetectors, lasers, light sources, and the like. In the example of fig. 1, IC die 106 is a logic die and IC die 126 is a plurality of memory dies stacked on a buffer die. The stack of IC dies 126 may be encapsulated in a polymer overmold compound 128.

In the example depicted in fig. 1, the chip package assembly 100 is configured as a High Bandwidth Memory (HBM) device, with the IC die 106 configured as a logic die, such as a Field Programmable Gate Array (FPGA), and the IC die 126 configured as an HBM die stack. It is contemplated that the type of IC die 106, 126 comprising the chip package assembly 100 may be the same or different, including types other than HBM die and FPGA die.

Each IC die 106, 126 includes a bottom surface 140 and a top surface 142. The bottom surface 140 of the IC die 106 is coupled to the top surface 146 of the redistribution layer 102. The bottom surface 140 of the bottommost IC die 126 is also coupled to the top surface 146 of the redistribution layer 102. The bottom surface 144 of the redistribution layer 102 is coupled to the top surface 138 of the interposer substrate 104 by solder connections 118 or other suitable electrical connections. An optional lid (not shown) may be disposed on the top surface 142 of the IC die 106, 126. When a lid or other heat spreader is present on IC die 106, a Thermal Interface Material (TIM) may be disposed between top surface 142 of IC die 106, 126 and the bottom surface of the lid to enhance heat transfer therebetween. In one example, the TIM may be a thermal gel or a thermal epoxy, such as a package component attachment adhesive. In some implementations, a separate heat sink may be disposed over and in contact with the cover.

Additionally, optional stiffeners (not shown) may be used to enhance the stiffness of the chip package assembly 100. When used, the stiffener may be made of ceramic, metal, or other various inorganic materials and coupled to one of the interposer substrate 104 or the package substrate 108.

As discussed above, the circuitry of the IC dies 106, 126 is connected to the circuitry of the redistribution layer 102. In fig. 2, details of the connections between the IC dies 106, 126 and the redistribution layer 102 are further detailed. The redistribution layer 102 also contacts a bottom surface 114 of the molding compound 112.

Referring to the partial cross-sectional view of fig. 2, the IC die 106, 126 includes a contact pad 202, and the circuitry 160 of the IC die 106, 126 terminates at the contact pad 202. The contact pads 202 are exposed to the bottom surface 140 of the IC dies 106, 126. The top surface 146 of the redistribution layer 102 is fabricated directly on the bottom surface 140 of the IC die 106, 126. The redistribution layer 102 includes at least three metal layers and dielectric layers that are patterned to produce circuitry 162 of the redistribution layer 102. In one example, the wiring 204, including circuitry 162 formed by patterned metal lines 206 and vias 208 within the dielectric layer 210, is directly connected on the top surface 146 of the RDL 102 without solder connections. In this manner, the spacing between contact pads 202 may have a finer pitch than connections using solder interconnects. The wiring 204 including circuitry 162 terminates and is exposed at the bottom surface 144 of the RDL to facilitate solder connection with circuitry of an underlying substrate (e.g., circuitry 164 of interposer substrate 104).

Returning only to fig. 1, the circuitry 162 of the redistribution layer 102 is electrically and mechanically coupled to the circuitry 164 of the interposer substrate 104 by the solder connections 118. Circuitry 164 of interposer substrate 104 is similarly connected to circuitry 166 of package substrate 108. In the example depicted in fig. 1, the bottom surface 136 of the interposer substrate 104 is electrically and mechanically coupled to the top surface 134 of the package substrate 108 by solder connections 118 or other suitable connections.

The chip package assembly 100 may be mounted to a Printed Circuit Board (PCB)116 to form an electronic device 150. In this manner, circuitry 166 of package substrate 108 is coupled to circuitry 168 of PCB 116 via solder balls 122 or other suitable connections. In the example depicted in fig. 1, the bottom surface 132 of the package substrate 108 is electrically and mechanically coupled to the top surface 130 of the PCB by solder balls 122.

The molding compound 112 is in contact with the top surface 146 of the redistribution layer 102. The molding compound 112 also fills the gaps 120 defined between the IC dies 106, 126. Molding compound 112 is also present on the outside of IC die 106 opposite gap 120 (i.e., on the side of IC die 106 opposite adjacent die 126). In embodiments that utilize only a single die, the molding compound 112 is disposed laterally outward of the IC die 106.

The molding compound 112 provides additional rigidity to the package assembly 100 while also protecting the electrical connections between the IC dies 106, 126 and the circuitry of the redistribution layer 102. The molding compound 112 may be a polymer material such as an epoxy-based material or other suitable material. When the IC die 126 is disposed in the overmolding compound 128, the molding compound 112 is in contact with the overmolding compound 128, the redistribution layer 102, and the IC die 106.

The pillars 110 are disposed in a molding compound 112. The pillars 110 are used to increase the cracking or delamination resistance of the molding compound 112 from the sides of the IC dies 106, 126, particularly when a portion of the molding compound 112 is removed to expose the bottom surfaces 140 of the IC dies 106 for electrically coupling the circuitry 160 of the IC dies 106, 126 to the circuitry 162 of the redistribution layer 102. When the overmolding compound 128 is present, the posts 110 also increase resistance to cracking, separation, or delamination of the molding compound 112 from the molding compound 128.

The post 110 is made of a material having a hardness greater than the hardness of the molding compound 112. The pillar 110 may be made of a dielectric or metallic material. In one example, the pillars 110 are made of one or more metal layers. For example, the post 110 may be made of copper, titanium, or other suitable metallic material. When the pillars 110 are made of copper, the pillars 110 may include one or more seed layers to facilitate plating, such as titanium, tungsten, tantalum, and nickel vanadium.

Pillars 110 generally have an elongated geometry with a major axis along the long direction that is substantially perpendicular to a bottom surface 140 of IC die 106 and a top surface 138 of interposer substrate 104. The cross-sectional profile of the post 110 is substantially circular, but may have any other suitable geometry.

The bottom surfaces 170 of the pillars 110 are generally coplanar with the top surface 146 of the redistribution layer 102. The bottom surface 170 of the pillar 110 is also generally coplanar with the bottom surface 114 of the molding compound 112. Each pillar 110 generally extends from a bottom surface 170 to a top surface 172 such that a length of pillar 110 defined between surfaces 170, 172 at least partially overlaps a sidewall 124 of IC die 106. Sidewalls 124 of IC die 106 generally define the height of IC die 106, that is, the distance between top surface 140 and bottom surface 142 of IC die 106.

In one example, the top surface 172 of the pillar 110 is coplanar with the top surface 142 of the IC die 106. In another example, the top surface 172 of the pillar 110 is located below the top surface 142 of the IC die 106. Regardless of the position of the top surface 172, the bottom surface 170 of the pillar 110 may extend below the bottom surface 140 of the IC die 106. It is contemplated that in some examples, the bottom surface 170 may extend into the redistribution layer 102.

In another example with IC dies 126 in a stacked arrangement, top surfaces 172 of pillars 110 are coplanar with top surface 142 of the uppermost IC die 126. In another example, top surface 172 of pillar 110 is located below top surface 142 of uppermost IC die 126. Regardless of the position of top surface 172, bottom surface 170 of pillar 110 may extend below bottom surface 140 of bottommost IC die 126. It is contemplated that in some examples, the bottom surface 170 may extend into the redistribution layer 102.

The pillars 110 may be formed before or after the molding compound 112 is deposited. For example, pillars 110 may be formed on a temporary carrier (as shown and described below) before or after molding compound 112 is deposited around IC die 106 and pillars 110. The pillars 110 may be formed on the temporary carrier, for example, by plating or other suitable deposition techniques. In another example, the molding compound 112 may be deposited around the IC dies 106, 126, and then holes are formed in the molding compound 112, the pillars 110 being disposed in the molding compound 112. The holes containing pillars 110 may be formed by etching, laser drilling, embossing, thermoforming, mechanical drilling, or other suitable techniques.

Generally, the pillars 110 are provided to improve the cracking resistance and delamination resistance of the molding compound 112. As such, the pillars 110 are not coupled to the circuitry 160 of the IC dies 106, 126. The pillars 110 may also be coupled to circuitry 162 of the redistribution layer 102. The post 110 may also not be coupled to the circuitry 164 of the interposer substrate 104. In the example depicted in fig. 1, the pillars 110 are electrically floating with respect to one or more or even all of the circuitry 160, 162, 164 of the IC dies 106, 126, the redistribution layer 102, and the interposer substrate 104.

The post 110 may be made of a material that increases the stiffness of the molding compound 112. Suitable materials include materials that have good adhesion and greater hardness than the molding compound 112. Suitable materials may be electrically conductive or non-conductive materials. Suitable materials may be more thermally conductive than the molding compound 112. Suitable materials include metals such as copper, solder, titanium, tantalum, and nickel vanadium, among others. Suitable materials also include industrial diamond retained in a binder. The post 110 may be a single solid or composed of multiple elements such as powder, metal wool, or discrete shapes held in a binder. The material comprising the post 110 may also be solder paste, metal fibers, metal powders, metal particles, metal spheres, thermally conductive adhesives, or other suitable thermally conductive materials.

In one example, the pillars 110 are thermally conductive and provide a robust electrically conductive heat transfer path between the IC dies 106, 126 vertically away from the top surface 138 of the interposer substrate 104. If a lid (not shown) is utilized over the die 106, 126, a Thermal Interface Material (TIM) may be utilized between the pillar 110 and the lid to provide a robust heat transfer interface between the pillar 110 and the lid to draw heat away from between the IC die 106, 126.

The pillars 110 may have any suitable cross-sectional profile and typically have a length that is at least as long as the height of the IC die 106. In one example, the cross-sectional profile of the post 110 is circular. The number, size, density, and location of pillars 110 may be selected to provide a desired shear resistance between the molding compound 112 and at least one of the IC dies 106, 126 and the overmolding compound 128 (if present).

Fig. 3 is a schematic top view of the chip package assembly 100 of fig. 1 to show an exemplary geometric arrangement of pillars 110 disposed between IC dies 106, 126. In the example depicted in fig. 3, the pillars 110 include pillars 302 disposed between adjacent IC dies 106, 126. Optionally, the pillars 110 may include pillars 304 disposed outside the IC dies 106, 126 and between the IC dies 106, 126 and the edge 308 of the interposer substrate 104. In other words, the pillars 304 are disposed outside of the IC dies 106, 126 (outside of the over-mold compound 128, if present) and are surrounded by the mold compound 112. The location, size, and density of the struts 302 can be selected to enhance the shear resistance, cracking resistance, or delamination resistance of the molding compound 112 in desired locations. The location, size, and density of the pillars 304 (if present) may be selected to enhance vertical heat transfer through the molding compound 112 in a desired location. Additional details of the post 110 are provided in the illustrative, non-limiting examples provided in the figures described further below.

Fig. 4 is a flow chart of a method 400 of manufacturing a chip package assembly, such as the chip package assembly 100 described above with reference to fig. 1-2, having electrically floating pillars 110 between adjacent IC dies. Fig. 5A-5F are schematic cross-sectional views of a chip package assembly at different stages of the method 400 of fig. 4. Note that the orientation of the dies 106, 126 and other components illustrated in fig. 5A-5F are 180 deg. different than fig. 1. In other words, the orientation of the dies 106, 126 and other components illustrated in fig. 5A-5F is reversed compared to the orientation shown in fig. 1.

As shown in fig. 5A, the method 400 begins at operation 402, where the IC dies 106, 126 are attached to a carrier 500. The carrier 500 is used only during initial manufacturing operations, such that the carrier 500 is removably attached to attach the IC dies 106, 126 prior to mounting the IC dies 106, 126 to a substrate, such as the interposer substrate 104, and completing the fabrication of the chip package assembly 100. In one example, the top surfaces 142 of the IC dies 106, 126 are attached to the carrier 500 using a releasable pressure sensitive adhesive. The IC die or dies 126 may be encapsulated in an overmolding compound 128, such as the overmolding compound described and illustrated above with reference to fig. 1.

At operation 404, the molding compound 112 is disposed around the dies 106, 126 and in contact with the carrier 500. The molding compound 112 extends beyond the bottom surface 140 of the IC die 106, 126 to an initial surface 540, as illustrated in fig. 5B. The initial height 542 is defined as the distance defined between the initial surface 540 and the bottom surface 140 of the IC die 106, 126. The molding compound 112 may be spin-coated, dispensed, over-molded, or deposited by another suitable method. At operation 404, the molding compound 112 fills the gaps 120 defined between adjacent dies 106, 126.

At operation 406, holes 502 are formed in the molding compound 112 between the IC dies 106, 126, as shown in fig. 5C. The holes 502 may be formed, for example, by etching, laser drilling, embossing, thermoforming, mechanical drilling, or other suitable techniques. The depth of the hole 502, which may be less than the initial height 542, extends to a distance defined between the top surface 140 and the bottom surface 142 of the IC die 106, or to the carrier 500 (such that the end 502 of the hole is substantially coplanar with the top surface 142 of the IC die 106, 126, such that the carrier 500 is exposed through the hole 502).

At operation 408, the holes 502 are then filled with a reinforcing material to form the pillars 110, as shown in fig. 5D. The apertures 502 may be formed by dispensing material into the apertures 502 or plating material in the apertures 502 to form the apertures 110. In one example, a seed layer 504 is deposited in the hole 502. For example, the seed layer 504 may be deposited on the molding compound 112 forming the bottom of the aperture 502, or may be deposited on the carrier 500 when exposed through the aperture 502. The seed layer 504 may be deposited using chemical vapor deposition, physical vapor deposition, inkjet printing, or other suitable techniques. The seed layer 504 provides an adhesion layer for the metal material subsequently deposited in the holes 502 to continue forming the pillars 110. The seed layer 504 may optionally be deposited on the sidewalls of the holes 502. In the example shown in fig. 5D, the seed layer 504 is made of copper. After depositing the seed layer 504, a body conductor 506 is deposited on the seed layer 504, as shown in FIG. 5D. The body conductor 506 may be deposited on the seed layer 504 using electroless plating, electroplating, chemical vapor deposition, physical vapor deposition, or other suitable technique. The body conductor 506 fills the hole 502 completely or near the initial surface 540 of the molding compound 112. In the example shown in fig. 5D, the bulk conductor 506 is copper, which is plated directly on the seed layer 504. When holes 502 are shallow, advantageously, less material is needed to fill holes 502 and form pillars 110, which saves cost. When the holes 502 are deep, the conductive material filling the holes 502 and forming the pillars 110 facilitates heat transfer out of the chip package assembly 100, which advantageously improves performance reliability.

At operation 410, the initial surface 540 of the molding compound 112 and the ends of the pillars 110 are ground, mechanically or otherwise removed to make the bottom surface 114 of the molding compound 112, the die contact pads 202, and the bottom surfaces 170 of the pillars 110 coplanar, as shown in fig. 5E. The pillars 110 inhibit the mold compound 112 from cracking, delaminating, or otherwise separating from the sidewalls 124 (and/or the overmold compound 128, when present) of the die 106, 126. Since the sidewalls 124 of the dies 106, 126 are less likely to crack, delaminate, or otherwise separate from the sidewalls 124 of the dies 106, 126, such defects are less likely to propagate into the RDL layer 102, where one or more of the wires 204 may be damaged, resulting in reduced performance or even failure of the chip package assembly 100.

At operation 412, the RDL layer 102 is fabricated directly on the bottom surface 114 of the molding compound 112 without using solder connections, as shown in fig. 5F. The RDL layer 102 is fabricated by depositing at least three or more dielectric layers that form the metal wiring 204. The metal routing 204 may be in the form of interconnecting metal lines 206 and vias 208 that form the circuitry 162 of the redistribution layer 102.

At operation 414, the carrier 500 is removed and the RDL layer 102 is electrically and mechanically connected to the interposer substrate 104 using solder connections 118, as shown in fig. 1. At operation 414, the package substrate 108 is electrically and mechanically connected to the interposer substrate 104 using the solder connectors 118 to complete the fabrication of the chip package assembly 100. Manufacturing the chip package assembly 100 may include other steps and components in addition to utilizing the pillars 110 described above.

Fig. 6 is a flow diagram of a method 600 of fabricating a chip package assembly, wherein the IC dies 106, 126 are disposed in the molding compound 112, similar to the chip package assembly 100 described above with reference to fig. 1-2, except that the chip package assembly fabricated using the method 600 optionally does not require the provision of electrically floating pillars 110 between adjacent IC dies 106, 126. Fig. 7A-7G are schematic cross-sectional views of a chip package assembly at different stages of the method 600 of fig. 6. It should be noted that the orientation of the dies 106, 126 and other components illustrated in fig. 7A-7G is 180 degrees different than that of fig. 1. In other words, the orientation of the dies 106, 126 and other components illustrated in fig. 7A-7G is reversed compared to the orientation shown in fig. 1.

The method 600 begins at operation 602, where at operation 602 the IC dies 106, 126 are attached to the carrier 700, as shown in fig. 7A. The carrier 700 is used only during initial manufacturing operations, such that the carrier 700 is removably attached to attach the IC dies 106, 126 prior to mounting the IC dies 106, 126 to a substrate, such as the interposer substrate 104, and completing the chip package assembly 100 manufacture. In one example, the top surfaces 142 of the IC dies 106, 126 are attached to the carrier 700 using a releasable pressure sensitive adhesive. The IC die or IC dies 106, 126 may be encapsulated in an overmolding compound 128, such as the overmolding compound described and illustrated above with reference to fig. 1.

At operation 604, the molding compound 112 is disposed around the dies 106, 126 and in contact with the carrier 700. The molding compound 112 extends beyond the bottom surface 140 of the IC die 106, 126 to an initial surface 740, as illustrated in fig. 7B. The initial height 742 is defined as the distance defined between the initial surface 740 and the bottom surface 140 of the IC die 106, 126. The molding compound 112 may be spin-coated, dispensed, over-molded, or deposited by another suitable method. At operation 604, the molding compound 112 fills the gaps 120 defined between adjacent dies 106, 126. As shown in fig. 7B, the spacing between the distal ends 702 of the contact pads 202 and the initial surface 740 of the molding compound 112 may vary across individual ones of the IC dies 106, 126 and/or may vary across the IC dies 106, 126. The thickness of the molding compound 112 is typically greater than or equal to the distance that the longest of the contact pads 202 extends beyond the bottom surface 140 of the IC die 106, 126.

At operation 606, an initial surface 740 of the molding compound 112 is selectively etched relative to the pillars 110 to define secondary surfaces 704 in the molding compound 112, as shown in FIG. 7C. The selective etching allows the distal ends 702 of the contact pads 202 to extend beyond the secondary surface 704 of the molding compound 112.

At operation 608, a polymer layer 706 is deposited on the secondary surface 704 of the molding compound 112 and patterned on the secondary surface 704 of the molding compound 112, as shown in FIG. 7D. The polymer layer 706 is patterned such that a recess 708 is formed to expose the distal end 702 of the contact pad 202. In one example, a groove 708 is formed around each distal end 702 of the contact pad 202. The thickness of the polymer layer 706 is sufficient to recess each distal end 702 of the contact pad 202 within the recess 708. In other words, after patterning the polymer layer 706, the distal end 702 is located below the secondary surface 704 of the molding compound 112. In one example, polymer layer 706 is formed of polyimide or other suitable dielectric material. After patterning, the exposed surface of the polymer layer 706 becomes the bottom surface 114 of the molding compound 112.

At operation 610, the grooves 708 are filled with a conductive material 710 and made coplanar with an initial surface 740 of the molding compound 112, as shown in fig. 7E. The conductive material 710 filling the recess 708 extends the circuitry 160 of the die 106, 126 to be coplanar with the bottom surface 114 of the molding compound 112 so that the circuitry 162 of the RDL layer 102 may be formed directly on the conductive material 710 (i.e., without solder connections). Because the molding compound 112 is not subjected to grinding or other mechanical processes that induce shear forces to the molding compound 112, the molding compound 112 is substantially unaffected by the sidewalls 124 of the die 106, 126 (and/or the overmolding compound 128, if present) from cracking, delaminating, or separating from the sidewalls 124 of the die 106, 126. Because the sidewalls 124 of the dies 106, 126 are less likely to crack, delaminate, or otherwise separate from the sidewalls 124 of the dies 106, 126, such defects are less likely to propagate into the RDL layer 102, where one or more of the wires 204 may be damaged, resulting in reduced performance or even failure of the chip package assembly 100.

At operation 612, the RDL layer 102 is fabricated directly on the bottom surface 114 of the molding compound 112 without using solder connections, as shown in fig. 7F. The RDL layer 102 is fabricated by depositing at least three or more dielectric layers that form the metal wiring 204. The metal routing 204 may be in the form of interconnect metal lines 206 and vias 208 that form the circuitry 162 of the redistribution layer 102. By fabricating the RDL layer 102 directly on the bottom surface 114 of the molding compound 112 without using solder connections, a higher pitch density for the electrical interface with the dies 106, 126 may be achieved.

At operation 614, the carrier 700 is removed and the RDL layer 102 is electrically and mechanically connected to the interposer substrate 104 using solder connections 118, as shown in fig. 7G. At operation 614, the package substrate 108 is also electrically and mechanically connected to the interposer substrate 104 using the solder connections 118 to complete the fabrication of the chip package assembly 700. The chip package assembly 700 is substantially identical to the chip package assembly 100 except for the lack of posts 110 and the configuration of how the contact pads 202 and conductive material 710 connect between the circuitry 160 of the IC dies 106, 126 and the circuitry 162 of the RDL layer 102. The fabrication 700 of the chip package assembly may include other steps and components.

Fig. 8 is a flow chart of a method 800 of fabricating a chip package assembly, wherein the IC dies 106, 126 are disposed in the molding compound 112, similar to the chip package assembly 100 described above with reference to fig. 1-2, except that the chip package assembly fabricated using the method 600 optionally does not require the provision of electrically floating pillars 110 between adjacent IC dies 106, 126. Fig. 9A-9I are schematic cross-sectional views of a chip package assembly at different stages of the method 800 of fig. 8. It should be noted that the orientation of the dies 106, 126 and other components illustrated in fig. 9A-9I are different by 180 degrees compared to fig. 1. In other words, the orientation of the dies 106, 126 and other components illustrated in fig. 9A-9I is reversed compared to the orientation illustrated in fig. 1.

The method 800 begins at operation 802, where at operation 802 the IC dies 106, 126 are attached to a carrier 900, as shown in fig. 9A. The carrier 900 is used only during initial manufacturing operations, such that the carrier 900 is removably attached to attach the IC dies 106, 126 prior to mounting the IC dies 106, 126 to a substrate, such as the interposer substrate 104, and completing the chip package assembly 100 manufacture. In one example, the top surfaces 142 of the IC dies 106, 126 are attached to the carrier 900 using a releasable pressure sensitive adhesive. The IC die or IC dies 106, 126 may be encapsulated in an overmolding compound 128, such as the overmolding compound described and illustrated above with reference to fig. 1.

At operation 804, the molding compound 112 is disposed around the dies 106, 126 and in contact with the carrier 900. The molding compound 112 extends beyond the bottom surface 140 of the IC die 106, 126 to an initial surface 940, as shown in fig. 9B. Initial height 942 is defined as the distance defined between initial surface 940 and bottom surface 140 of IC die 106, 126. The molding compound 112 may be spin-coated, dispensed, over-molded, or deposited by another suitable method. At operation 804, the molding compound 112 fills the gaps 120 defined between adjacent dies 106, 126. As shown in fig. 9B, the spacing between the distal ends 702 of the contact pads 202 and the initial surface 940 of the molding compound 112 may vary across individual ones of the IC dies 106, 126 and/or across the IC dies 106, 126. The thickness of the molding compound 112 is typically greater than or equal to the distance that the longest of the contact pads 202 extends beyond the bottom surface 140 of the IC die 106, 126.

At operation 806, an initial surface 940 of the molding compound 112 is selectively etched relative to the pillars 110 to define a secondary surface 904 in the molding compound 112, as shown in FIG. 9C. The selective etching allows the distal ends 702 of the contact pads 202 to extend beyond the secondary surface 904 of the molding compound 112.

At operation 808, a resist layer 906 is deposited on the secondary surface 904 of the molding compound 112, as shown in FIG. 9D. A resist layer 906 is deposited to a thickness that covers all but not most of the contact pad 202.

At operation 810, a top portion of resist layer 906 is removed to make exposed surface 908 of resist layer 906 coplanar with distal ends 702 of contact pads 202, as shown in fig. 9E. The top portion of resist layer 906 may be removed by chemical mechanical polishing, fly-cut (fly-cut), or other suitable process. Operation 808 also removes a portion of some or all of the contact pads 202 such that the distal ends 702 of the contact pads 202 become coplanar with each other and with the exposed surface 908 of the resist layer 906. Since the molding compound 112 is protected from the stresses induced while the top portion of the resist layer 906 and a portion of the contact pad 202 are removed, crack initiation, cracking, and delamination of the molding compound 112 are substantially prevented.

At operation 812, the remaining resist layer 906 is removed, as shown in FIG. 9F. The resist layer 906 may be removed by a resist stripping process (e.g., chemical resist removal or other suitable process).

At operation 814, a polymer layer 706 is deposited on the molding compound 112 and patterned on the molding compound 112, as shown in FIG. 9G. The polymer layer 706 is patterned such that a groove 708 is formed around each distal end 702 of the contact pad 202. The thickness of the polymer layer 706 is sufficient to recess each distal end 702 of the contact pad 202 within the recess 708. In other words, after patterning polymer layer 706, distal end 702 is located below the top surface of polymer layer 706. In one example, polymer layer 706 is formed of polyimide or other suitable dielectric material. After patterning, the exposed surface of the polymer layer 706 becomes the bottom surface 114 of the molding compound 112.

At operation 816, the groove 708 is filled with the conductive material 710 and made coplanar with the bottom surface 114 of the molding compound 112 (e.g., the polymer layer 706), as shown in fig. 9H. The conductive material 710 filling the recess 708 extends the circuitry 160 of the die 106, 126 to be coplanar with the bottom surface 114 of the molding compound 112 so that the circuitry 162 of the RDL layer 102 may be formed directly on the conductive material 710 (i.e., without solder connections). Since the molding compound 112 is protected by the resist layer 906, the molding compound 112 is substantially unaffected by the sidewall 124 of the die 106, 126 (and/or the overmolding compound 128, if present) cracking, delaminating, or otherwise separating from the sidewall 124 of the die 106, 126, since the molding compound 112 has not been subjected to grinding or other mechanical processes that induce shear forces to the molding compound 112. Because the sidewalls 124 of the dies 106, 126 are less likely to crack, delaminate, or otherwise separate from the sidewalls 124 of the dies 106, 126, such defects are less likely to propagate into the RDL layer 102, where one or more of the wires 204 may be damaged, resulting in reduced performance or even failure of the chip package assembly 100.

At operation 818, the RDL layer 102 is fabricated directly on the bottom surface 114 of the molding compound 112 without the use of solder connections, as shown in fig. 9I. The RDL layer 102 is fabricated by depositing at least three or more dielectric layers that form the metal wiring 204. The metal routing 204 may be in the form of interconnect metal lines 206 and vias 208 that form the circuitry 162 of the redistribution layer 102. By fabricating the RDL layer 102 directly on the bottom surface 114 of the molding compound 112 without using solder connections, a higher pitch density for the electrical interface with the dies 106, 126 may be achieved.

At operation 820, the carrier 900 is removed and the RDL layer 102 is electrically and mechanically connected to the interposer substrate 104 using solder connections 118, as shown in fig. 7G. The package substrate 108 is also electrically and mechanically connected to the interposer substrate 104 with solder connections 118 at operation 820 to complete the fabrication of the chip package assembly 700. As stated above, the chip package assembly 700 is substantially the same as the chip package assembly 100 except for the lack of posts 110 and the configuration of how the contact pads 202 and conductive material 710 connect between the circuitry 160 of the IC dies 106, 126 and the circuitry 162 of the RDL layer 102. The fabrication of the chip package assembly 700 may include other steps and components.

Accordingly, a chip package assembly and method of manufacturing the same have been provided that utilizes a plurality of pillars disposed around an Integrated Circuit (IC) die and a non-abrasive process that enhances crack resistance and/or delamination resistance of the molding compound and other polymer layers adjacent to the redistribution layer. Enhancing crack resistance and/or delamination resistance greatly improves the prevention of crack propagation into the fan-out of the redistribution layer, which can lead to damage or breakage of conductors within the redistribution layer circuitry. Therefore, the reliability and performance of the chip package assembly are significantly improved.

The disclosed technology may be described in the following non-limiting examples, except for the following claims. Example 1 grinding of molding compound was utilized in a manner that advantageously reduced the likelihood of crack initiation in the molding compound to take advantage of the cost savings associated with the grinding process. Examples 2-3 utilize techniques that advantageously eliminate grinding of the molding compound to reduce the probability of crack initiation in the molding compound.

Example 1: a method of fabricating a chip package assembly, comprising: attaching the IC die to a carrier; disposing a molding compound around the IC die; forming holes in the molding compound between the IC dies; filling the holes with a reinforcing material to form pillars; removing a portion of the molding compound and the ends of the pillars such that a bottom surface of the molding compound, the die contact pads, and the bottom surfaces of the pillars are coplanar; fabricating a redistribution layer directly on a bottom surface of the molding compound without using a solder connection; and removing the carrier, electrically and mechanically connecting the redistribution layer to the interposer substrate with a solder connection, and electrically and mechanically connecting the package substrate to the interposer substrate with a solder connection.

Example 2: a method of fabricating a chip package assembly, comprising: attaching the IC die to a carrier; disposing a molding compound around the die and in contact with the carrier; etching an initial surface of the molding compound selectively with respect to contact pads (i.e., pillars) extending from the IC die; depositing a polymer layer over the molding compound and patterning it to form a recess exposing the contact pad; filling the recess with a conductive material and making the conductive material coplanar with the molding compound; fabricating a redistribution layer directly on the molding compound without using a solder connection; the carrier is removed and the redistribution layer is electrically connected to the interposer substrate with solder connections and the package substrate is electrically and mechanically connected to the interposer substrate with solder connections.

Example 3: a method of fabricating a chip package assembly, comprising: attaching the IC die to a carrier; disposing a molding compound around the die and in contact with the carrier; etching an initial surface of the molding compound selectively with respect to contact pads (i.e., pillars) extending from the IC die; depositing a resist layer on the molding compound; removing a top portion of the resist layer to make an exposed surface of the resist layer coplanar with the distal end of the contact pad; removing the residual resist layer; depositing a polymer layer on the molding compound and patterning it to form a recess, filling the recess with a conductive material and making the conductive material coplanar with the molding compound; fabricating a redistribution layer directly on the molding compound without using a solder connection; the carrier is removed, the redistribution layer is electrically and mechanically connected to the interposer substrate using solder connections, and the package substrate is then electrically and mechanically connected to the interposer substrate using solder connections.

Example 4: a chip package assembly comprising a first Integrated Circuit (IC) die; a substrate; a redistribution layer having circuitry that provides electrical connections between the circuitry of the first IC die and the circuitry of the substrate; a molding compound disposed in contact with the first IC die and separated from the substrate by a redistribution layer; a plurality of contact pads extending from the first die and having ends exposed in recesses formed in the molding compound; and a conductive material disposed in the groove and electrically coupling circuitry of the substrate to circuitry of the redistribution layer.

Example 5: a chip package assembly comprising a first Integrated Circuit (IC) die; a substrate; a redistribution layer having circuitry that provides electrical connections between the circuitry of the first IC die and the circuitry of the substrate; a molding compound disposed in contact with the first IC die and separated from the substrate by a redistribution layer; a dielectric layer disposed between the molding compound and the redistribution layer; a plurality of contact pads extending from the first die and having ends exposed in recesses formed in the dielectric layer; and a conductive material disposed in the groove and electrically coupling circuitry of the substrate to circuitry of the redistribution layer.

Advantageously, the methods of at least examples 2 and 3 may also be used to increase the height and reshaping of the pillars (i.e., contact pads), thereby increasing the molding compound buffer between the bottom surface of the IC die and the top surface of the RDL layer. The method may also be used to increase the stud size to accommodate obtaining IC dies from third party vendors that cannot or do not provide uniform stud sizes.

While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.