Coplanar control for film-like thermal interfaces

Abstract

Procedure comprehensive: Bonding of a first package (32) and a second package (32) over a package component (20, 22, 34, 46, 46A-C); Applying a first thermal interface material, TIM , (64) and a second TIM (64) over the first and second package (32), respectively; After the first TIM (64) and the second TIM (64) have been glued on, a first adhesive element (66, 66A, 66B, 68) is applied to the package component (20, 22, 34, 46, 46A-C); Arranging a heat sink (70) over the first adhesive element (66, 66A, 66B, 68) and in contact with it, wherein the heat sink (70) comprises a section (70A) above the first TIM (64) and the second TIM (64); and Curing of the first adhesive element (66, 66A, 66B, 68), wherein at a first time point after the application of the first adhesive element (66, 66A, 66B, 68) and before the curing of the first adhesive element (66, 66A, 66B, 68) the first adhesive element (66, 66A, 66B, 68) has a first upper surface which is higher than a second upper surface of the first TIM (64), and the first adhesive element (66, 66A, 66B, 68) is in physical contact with the package component (20, 22, 34, 46, 46A-C).

Description

BACKGROUND

[0001] Integrated circuits can consist of a variety of package components, such as device chips and package substrates, bonded together to increase functionality and integration level. Due to differences in the materials used in the multiple package components, warpage can occur. As the package size increases, the warpage becomes more severe. This leads to several new problems. For example, thermal interface material can be used to conduct heat from the packages within the IC packages to the heat sinks. Due to warpage, delamination can occur between the thermal interface material and the corresponding device chips or packages. Delamination typically occurs at points where different materials / components are adjacent, such as...at the corners of device chips or packages and on weakly adhesive surfaces such as the surface of molding compound.

[0002] Publication documents US 2020 / 0 235 083 A1, US 2018 / 0 358 280 A1, EP 3 758 058 A1 and WO 2019 / 066 993 A1 disclose various integrated circuits with a plurality of package components, wherein a cover is placed over the package components. DE 10 2018 109 490 A1 discloses silicone sheets with non-stick cut surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Aspects of this disclosure are best understood by referring to the following detailed description when read in conjunction with the accompanying figures. It should be noted that, in accordance with common industry practice, various features are not drawn to scale. Indeed, the dimensions of the various features may be arbitrarily enlarged or reduced for the sake of clarity of discussion.

[0004] The Fig. show cross-sectional views of intermediate stages in the manufacture of a package with adhesive elements according to some embodiments.

[0005] Fig. shows the cross-sectional view of a package with adhesive elements according to some embodiments.

[0006] Fig. shows the cross-sectional view of a package with adhesive elements according to some embodiments.

[0007] The Fig. show cross-sectional views of intermediate stages in the manufacture of a package with a rod lid according to alternative embodiments.

[0008] Fig. shows the cross-sectional view of a package with a rod cover and a heat sink with a fin according to some embodiments.

[0009] The Fig. show the top view of packages according to some embodiments.

[0010] Fig. illustrates a process flow for manufacturing a package in accordance with some embodiments. DETAILED DESCRIPTION

[0011] Improved package devices and a method for manufacturing such a package device are provided by the independent claims. The following disclosure provides many different embodiments or examples of implementing various features of the invention. To simplify the present disclosure, specific examples of components and arrangements are described below. For example, the formation of a first feature over or on a second feature in the following description may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features can be formed between the first and second features, such that the first and second features cannot be in direct contact.Furthermore, reference numbers and / or letters may be repeated in the various examples in this disclosure. This repetition serves the purpose of simplicity and clarity and does not in itself establish a relationship between the various embodiments and / or configurations discussed.

[0012] Furthermore, for the sake of simplicity, spatially relative terms such as "below," "under," "below," "above," "above," and the like can be used here to describe the relationship of one element or feature to another, as illustrated in the figures. These spatially relative terms are intended to encompass various orientations of the device in use or operation, in addition to the orientation shown in the figures. The device may be oriented differently (rotated by 90 degrees or in other orientations), and the spatially relative terms used here can be interpreted accordingly.

[0013] A package and the method for its fabrication are provided. According to some embodiments of the present disclosure, a first package component (e.g., a package) is bonded to a second package component (e.g., a package substrate). A thermal interface material (TIM) is applied to the first package component. An adhesive is also applied to the second package component to form an adhesive element. A heat sink, which may also be a lid, can be placed over and bonded to the adhesive element. The adhesive element can help to reduce warpage of the resulting package and to minimize delamination between the TIM and the underlying first package component.The embodiments discussed here are intended to serve as examples of the manufacture or use of the subject matter of this disclosure, and a person skilled in the art will readily understand that modifications may be made while remaining within the scope of the various embodiments considered. In the different views and embodiments, identical elements are identified by the same reference numerals. Although the method implementations are described in a specific order, other method implementations may be carried out in any logical sequence.

[0014] The Fig. The figures show cross-sectional views of intermediate stages in the production of a package with adhesive elements according to some embodiments. The corresponding processes are also described in the figure in Fig. The process flow is shown schematically.

[0015] Fig. Figure 1 shows a cross-sectional view of a package component 20 containing a plurality of identical package components 22. In some embodiments, the package component 20 is a package substrate strip containing a plurality of package substrates 22. The package substrates 22 can be cored package substrates with cores or coreless package substrates without cores. In alternative embodiments, the package component 20 can be of a different type, such as an interposer wafer, a printed circuit board, a reconstructed wafer, or the like. In some embodiments, the package component 20 can be free of (or contain) active components such as transistors and diodes. The package component 20 can also be free of (or contain) passive components such as capacitors, inductors, resistors, or the like.

[0016] According to some embodiments of the present disclosure, the package component 20 comprises a plurality of dielectric layers, which may include dielectric layers 24, dielectric layer 26 above dielectric layers 24, and dielectric layer 28 below dielectric layers 24. According to some embodiments, dielectric layers 26 and 28 may consist of dry films such as Ajinomoto Build-up Films (ABFs). Alternatively, dielectric layers 26 and 28 may consist of polybenzoxazole (PBO), polyimide, benzocyclobutene (BCB), or the like, which may be applied in a flowable form and then cured. When located in a core, dielectric layers 24 may be formed from epoxy, resin, glass fibers, prepreg (containing epoxy, resin, and / or glass fibers), glass, molding compound, plastic, combinations thereof, and / or multiple layers thereof.According to alternative embodiments, dielectric layers 24 can consist of polymers such as PBO, polyimide, BCB, or the like. Distribution lines 30 are formed in the dielectric layers 24, comprising metal conductors / pads and vias. The distribution lines 30 are interconnected to form through-connections in the package component 20.

[0017] If the package component 20 is not rigid enough to support itself and the structure above it, a support 10 is provided in some embodiments to support the package component 20. In alternative embodiments, the package component 20 is thick and rigid and can support the structure formed on it. Accordingly, the support 10 and the release liner 12 can be omitted. The support 10, if used, can be a glass substrate, an organic substrate, or the like. The release liner 12 is formed on the support 10 to attach the package components to the support 10. The release liner 12 can be made of a polymer-based material (e.g., a light-to-heat-conversion (LTHC) material), which may include a thermally removable epoxy-based material.

[0018] According to alternative embodiments, as in Fig. As shown, the package component 20 is pre-formed and placed over the separating film 12. According to alternative embodiments, the package component 20 is built up layer by layer on the separating film 12. For example, a dielectric top layer 28 can be formed on the separating film 12, followed by the layer-by-layer formation of the dielectric layers 24 and 26 and the redistribution lines (RDLs) 30. The corresponding dielectric layers 24, 26, and / or 28 can be formed from organic materials (e.g., polymers) such as polyimide, PBO, or the like. According to alternative embodiments of the present disclosure, the dielectric layers 24, 26, and / or 28 can be formed from inorganic dielectric materials such as silicon nitride, silicon oxide, silicon oxynitride, or the like, which can be deposited.The deposition process can include chemical vapor deposition (CVD), atomic layer deposition (ALD), plasma-enhanced chemical vapor deposition (PECVD), or other suitable deposition methods. The RDLs / Pads 30 can be manufactured by coating or, alternatively, by damascus steel fabrication.

[0019] As in Fig. As shown, packages 32 (also referred to as package components) are placed on package component 20. The corresponding process is designated as process 202 in the Fig. The process flow 200 is shown in Figure 15. Although one group (e.g., two) of packages 32 is shown, in this process multiple groups of packages 32 are placed, with each group being placed via a corresponding package component 22. The packages 32 contain device chips and may also contain other package components such as interposers, packages, chip stacks, or the like. In accordance with some embodiments, the packages 32 comprise the package components 34, 46A, and 46B ( Fig. According to some embodiments, the package components 34 are interposers comprising substrates 36 and the corresponding dielectric layers 38. Accordingly, the package components 34 can also be referred to as interposers 34, although the package components 34 may also be of other types. The structure of the interposers 34 is shown schematically, and details such as the multiple dielectric layers on the top and bottom surfaces of the substrate 36, metal conductors and vias, metal pads, or the like are not shown. Vias 40 (sometimes also referred to as silicon vias 40 when the substrate 36 is a silicon substrate) penetrate the substrate 36. The vias 40 are used to connect the conductive elements on the top and bottom surfaces of the substrate 36.Solder pads 42 can be located under and connected to the interposers and are used to bond the interposers 34 to the package component 20. Other bonding methods such as metal-to-metal direct bonding, hybrid bonding, or similar can also be used for bonding package components 34 to the package component 20.

[0020] According to some embodiments, the package components are 46A (and 46B, as in Fig. shown) bonded to the respective underlying package components 34. Fig. shows a cross-section in which a package component 46A is visible. Another cross-sectional view of package 32 is in Fig. The diagram shows that package components 46B are also connected to the same package component 34 (e.g., interposer) as package component(s) 46A. Package components 46A and 46B are different types of package components and are collectively referred to as package components 46.

[0021] Each of the package components 46 can be a device chip, a package containing one or more device chips, a system-on-chip (SoC) with a variety of integrated circuits (or device chips) integrated as a system, or the like. The device chips in the package components 46 can be or include logic chips, memory chips, input / output devices, integrated passive devices (IPDs), or the like, or combinations thereof. For example, the logic chips in the package components 46 can be central processing unit (CPU) chips, graphics processing unit (GPU) chips, mobile application chips, micro control unit (MCU) chips, baseband (BB) chips, application processor (AP) chips, or the like. The memory chips in the package components 46 can be static random-access memory (SRAM) chips, dynamic random-access memory (DRAM) chips, or the like.The device chips in the package components 46 can contain semiconductor substrates and interconnect structures.

[0022] In the following discussion, the package components 46A are referred to as device chips according to some embodiments, which, according to some embodiments, may be SoC chips. The package components 46B may be memory stacks, such as HBM (High-Performance Memory) stacks. The package components 46B may comprise memory chips 60, which form a chip stack, and an encapsulating material 62 (e.g., a molding compound) that encapsulates the memory chips 60. Viewed from above, the encapsulating material 62 may form a ring surrounding the memory chips 60.

[0023] As in Fig. As shown, the package component 46 (e.g., 46A) can be bonded to the underlying package component 34, for example, by solder pads 50. The underfill 54 is applied between the package components 46 and the underlying package component 34. According to some embodiments, the packages 32 are formed by a chip-on-wafer (CoW) bonding process in which the package components 46, which are discrete chips / packages, are bonded to the package components 34, which are located in an unsawed wafer, to form a reconstructed wafer. In some embodiments, no molding compound is poured onto the package components 46. In this way, a reconstructed wafer is formed. The reconstructed wafer is sawn to form discrete packages 32, which are bonded to the package component 20.

[0024] After placing the package 32 onto the package component 20, the solder areas 42 are remelted, and an underfill 44 can be introduced between the gaps between packages 32 and 20. The resulting structure is in Fig. The corresponding process is shown in the Fig. The process flow shown is represented as process 204. In another cross-section, which is shown in Fig. As shown in Figure 6B, other package components such as independent passive devices (IPDs) 46C may be present, bonded to the package component 20. According to some embodiments, the IPDs 46C are discrete capacitors, discrete inductors, discrete resistors, or the like, and no active devices such as transistors are formed in the IPDs 46C. In the following, the package components 20, 22, 34, 46A, 46B, and 46C are also referred to as package substrate strips 20, package substrates 22, interposer 34, device chips 46A, memory stacks 46B, and IPDs 46C, respectively, and these package components may also be other types of package components as described in the preceding sections.

[0025] Fig. shows an exemplary top view of some of the in Fig. (and Fig. and Fig. Features shown. The reference cross-section AA in Fig. corresponds to the in Fig. and Fig. shown cross-sectional view, and the reference cross-section BB in Fig. corresponds to the in Fig. cross-sectional view shown. As in Fig. As shown, two or more packages 32 can be bonded to the same package substrate 22. Each package 32 can contain one or more device chips 46A and a plurality of stacked memory stacks 46B. Each memory stack 46B can contain memory chips 60 and a molding compound 62 that forms (and surrounds) the memory chips 60. The packages 32 are separated from each other by a gap. The IPDs 46C can be bonded to the edge regions of the package component 22.

[0026] As in Fig. As shown, the TIMs 64 are attached to packages 32. The corresponding process is designated as process 206 in the Fig. The process flow shown in Figure 200 is illustrated. The TIMs 64 are film-like TIMs that are pre-formed and solid at the time of application, in contrast to liquid TIMs, which are dispensed in a flowable form and then harden into a solid material. According to some embodiments, the TIMs 64 contain a base material, which may be a polymer. The base material may consist of or be formed from a resin, acrylic, a PBO-based polymer, a silicone-based polymer, or the like. The TIMs 64 may contain rigid fillers, e.g., graphite, graphene, metal particles, or the like. The TIMs 64 can be dispensed and placed onto the packages 32 or applied by a roller. According to some embodiments, as shown in Figure 200, the TIMs 64 can be dispensed and placed onto the packages 32 or applied by a roller. Fig. As shown, the TIMs 64 can be larger, equal to, or smaller than the underlying packages 32 in the top view. Accordingly, the TIMs 64 are in contact with the top surfaces of the device chips 46A and the memory stack 46B. The thermal conductivity of the TIMs 64 can be higher than approximately 1 W / k*m, higher than approximately 5 W / k*m, higher than approximately 10 W / k*m, or higher.

[0027] As in Fig. As shown, the adhesive elements 66 are applied to the package substrate 22 and can be in physical contact with the package substrate 22. The corresponding process is described as process 208 in the Fig. The process flow 200 is illustrated. In accordance with some embodiments, the adhesive elements 66 are flowable and are applied by a dispensing device. The viscosity of the adhesive elements 66 is high, so that after dispensing they can remain standing and retain their shape until they have cured into a solid material. According to some embodiments, the adhesive elements 66 comprise a flowable base material that is adhesive. In some embodiments, the flowable base adhesive element consists of or comprises a silicon-based polymer, which may be polydimethylsiloxane (PDMS) or a similar material. The properties of the adhesive elements 66 are discussed in the following sections. The flowable base material in the adhesive elements 66 can be a homogeneous material, wherein the flowable base material in all of the adhesive elements 66 consists of the same material.

[0028] In some embodiments, the adhesive elements 66 consist of a homogeneous material, e.g., the free-flowing base material to which no filler has been added. In other embodiments, the adhesive elements 66 can contain the base material and a filler (in the form of filler particles) within the base material. The filler particles serve to improve the overall viscosity of the adhesive elements 66. According to some embodiments, the filler particles consist of aluminum oxide, silicon dioxide, boron nitride, rubber, or similar materials. The filler particles can be prefabricated solid particles that are mixed with the free-flowing base material.

[0029] In accordance with some embodiments where the adhesive elements 66 are flowable, the adhesive elements 66 are applied. Application can be carried out using a stencil and a squeegee to define the shape of the adhesive elements 66. Alternatively, the adhesive elements 66 can also be applied without a stencil. When applied without a stencil, the adhesive elements 66 may have irregular shapes. For example, the sidewalls of the adhesive surfaces 66 may not be vertical, but rather slanted and curved. The top surfaces of the adhesive surfaces 66 may also be non-planar. Thus, the adhesive elements 66 may, for example, have curved top surfaces and pointed or non-pointed ends. Furthermore, the shapes of the adhesive elements 66 are random and irregular when applied without a stencil, and the shapes of the adhesive elements 66 may differ from one another.

[0030] According to some embodiments, the adhesive elements 66 are located on the outer surfaces of the packages 32, as shown, for example, by adhesive elements 66A. The adhesive elements 66 are applied close to the packages 32 and can be as close to the packages 32 as possible, as long as this is feasible with the method. In accordance with some embodiments, as shown in Fig. As shown, the adhesive elements 66 are spaced from the packages 32 by small gaps. The adhesive elements 66 can also be spaced from or in contact with the nearest underfill 44. For example, the inner parts of the adhesive elements 66 can overlap and touch the outer parts of the underfill 44. The top surfaces of the adhesive elements 66A are higher than the top surfaces of the TIMs 64 at the time of delivery.

[0031] In some embodiments, a portion of the adhesive element 66 (referred to as adhesive element 66B) is distributed as gap-filling material between the packages 32. Adhesive element 66B contacts the sidewalls of the packages 32. The top surface of adhesive element 66B is lower than the top surfaces of the TIMs 64, so that the adhesive surface is not pressed against the top surfaces of the TIMs 64. The underside of adhesive element 66B can be in physical contact with the top surface of the package substrate 22 or, alternatively, be separated from the top surface of the packaging material 22 by an air gap 67. Furthermore, the top surface of adhesive element 66B can be higher or lower than the top surfaces of the packages 32 or be coplanar with them. According to alternative embodiments, adhesive element 66B is not formed, and the gap between adjacent packages 32 remains unfilled in subsequent processes.According to further alternative embodiments, a filler material, which, for example, has an elongation value lower than that of the adhesive element 66A and a hardness value higher than that of the adhesive element 66A, can be introduced into the gap between the packages 32 as a filler area. Accordingly, the adhesive element 66B is shown with dashed lines to indicate whether it can be formed or not, or whether it can be formed from a different material than the adhesive element 66A.

[0032] Fig. Figure 1 further illustrates the application of the adhesive element 68, which is applied to the top surface of the package substrate 22. The corresponding process is described as process 210 in the [reference to be added]. Fig. The process flow shown in Figure 200 is illustrated. The adhesive elements 68 can be applied as a ring around the packages 32 or in individual portions. According to some embodiments, the adhesive elements 68 and the adhesive elements 66A and 66B are made of the same material. In alternative embodiments, the adhesive elements 68 and the adhesive elements 66A and 66B are made of different materials. The application of the adhesive elements 68 can be omitted if the subsequently attached heat sink 70 ( Fig. 5) does not have a skirt attached to the package substrate 20. The thermal conductivity of the adhesive elements 68 may be lower than the thermal conductivity of the TIMs 64. For example, the thermal conductivity of the adhesive elements 68 may be lower than approximately 1 W / k*m, while a higher thermal conductivity may be assumed.

[0033] Next, as in Fig. The heat sink (or cover) 70 is shown attached to the TIMs 64. According to some embodiments, the heat sink 70 is also a cover if it has a lower part, which is a foot, and is referred to below as a heat sink. The corresponding process is described as process 212 in the Fig. The process flow 200 shown in Figure 15 is illustrated. In accordance with some embodiments, the package component 20 is located at the wafer level and comprises a plurality of package components 22. Accordingly, there are a plurality of heat sinks 70, each attached to one of the package components 22. In accordance with some embodiments, as shown in Figure 15, the package component 20 is located at the wafer level and comprises a plurality of package components 22. Accordingly, there are a plurality of heat sinks 70, each attached to one of the package components 22. Fig. As shown, the heat sink 70 comprises an upper part 70A, the underside of which is planar and contacts the TIMs 64. The heat sink 70 can further comprise a lower section 70B, which extends downwards to the adhesive elements 68. The lower part 70B can form a complete ring surrounding the packages 32 and the adhesive elements 66A and 66B. The upper part 70A can have a planar top surface, as shown in Fig. shown. According to alternative embodiments, the upper part 70A includes fins (which may be an integrated part of the heat sink 70 or a separate part that is bonded to the upper part 70A by another TIM), as shown in Fig. shown. According to alternative embodiments, the heat sink 70 does not include a lower section 70B. Accordingly, the method for applying adhesive elements 68, as shown in Fig. The section shown is skipped. During the attachment of the heat sink 70, the heat sink 70 is pressed downwards against the adhesive element 66A, the adhesive elements 68, and the TIMs 64 to ensure physical contact with these features. Regardless of whether the adhesive elements 66A have straight or irregular sidewalls, the sidewalls of the adhesive elements 66A become irregular after the heat sink 70 is pressed against them. The irregular sidewalls are represented by the dashed lines 66SW as an example. The irregular sidewalls 66SW can extend from the top to the bottom of the adhesive elements 66A.

[0034] A curing process is then carried out to solidify the adhesive elements 66 and 68. The corresponding process is described as process 214 in the Fig. The process sequence 200 is illustrated. In accordance with some embodiments, the curing process includes a thermal curing process carried out at a temperature in the range of approximately 120 °C to approximately 170 °C. The curing time can be in the range of approximately 150 minutes to approximately 180 minutes. After the curing process, the adhesive elements 66 have a low modulus and are softer than the underfills 44 and 54 and the molding compound 62 (see Fig. The adhesive elements 66 can also be elastic. Furthermore, the coefficient of thermal expansion (CTE) of the adhesive elements 66 can be greater than the CTE of the underfills 44 and 54 and the molding compound 62. The adhesive elements 66A can shrink during the curing process. Since the adhesive elements 66A are soft and elastic after the curing process, they can pull the heat sink 70 and the package substrate 22 towards each other. This can compensate for the warpage of the resulting package, so that the resulting package exhibits less warpage. The adhesive elements 66A also pull the heat sink 70 against the package 32, so that the TIMs 64 are pressed against the package 32. This reduces the delamination between the TIMs 64 and the packages 32. Furthermore, the molding compound 62 adheres less well to the TIMs 64 than silicon, and the formation of the adhesive elements 66A can reduce the delamination between the TIMs 64 and the package components 46B.

[0035] In some embodiments, the package component 20 is next detached from the support 10. According to some embodiments, a light beam, e.g., a laser beam, is projected onto the separating film 12, and the separating film 12 is decomposed by the heat of the light beam. The package component 20 and the structures above it are thus detached from the support 10. The resulting structure is in Fig. The solder areas 72 can be applied to the package component 22 and then melted, as also shown in Fig. depicted.

[0036] In a subsequent process, a singulation process can be carried out to saw the package component 20, so that the package components 22 are separated into individual package components. Each of the package components 22 forms a package 74 with the package components 46 above it and the heat sink 70.

[0037] In the embodiments described above, the heat sinks 70 are first attached to the package components, then the package component 20 is removed from the carrier 10, and subsequently the package component 20 is sawn. According to alternative embodiments, the package component 20 is first removed from the carrier 10, followed by sawing the package component 20, and then the heat sinks 70 are attached to individual package components 22.

[0038] The Fig. The images show various cross-sections of Package 74. The top view of Package 74 is in Fig. to see, whereby the in Fig. Cross section AA shown in Fig. and the one in Fig. shown cross-section BB in Fig. The heat sink 70 is shown. Fig. not shown. As in Fig. As shown, the adhesive elements 66 can be applied where the TIMs 64 are most likely to detach from the underlying elements. Areas where delamination is most likely include those with high density of the molding compound, such as areas 76 where two memory stacks 46B are adjacent due to the use of molding compound 62 in the memory stacks 46B. Accordingly, the adhesive elements 66A are formed near the space between the memory stacks 46B. The adhesive elements 66 can be arranged along the longitudinal edges of the packages 32.

[0039] Fig. Figure 74 shows a package in accordance with alternative embodiments. The structures, materials, and manufacturing processes according to these embodiments are essentially the same as in the Fig. 1-5, 6A and 6B, except that the heat sink 70 has additional ribs 70C.

[0040] The Fig. 8, Fig. 9, Fig. 10A and Fig. Figure 10B shows cross-sectional views of intermediate stages in the manufacture of a package according to alternative embodiments of the present disclosure. Unless otherwise specified, the materials and forming processes of the components in these embodiments are substantially the same as the same components described in the preceding embodiments. Fig. 1-5, 6A and 6B are identified by the same reference numerals. Details regarding the forming processes and materials of the components described in the Fig. 8, Fig. 9, Fig. 10A and Fig. The components shown in 10B can therefore be found in the discussion of the preceding embodiments.

[0041] The initial processes of these embodiments are essentially the same as in the Fig. , Fig. , Fig. until Fig. The resulting structure is also shown in Fig. As shown. In accordance with these embodiments, the adhesive element 66B is applied. The volume of the adhesive element 66B depends on the size of the heat sink rod 70D ( Fig. ) together, as explained in the following sections. On the other hand, the adhesive elements 66A may or may not be applied. Accordingly, the adhesive elements 66A are shown with dashed lines to clarify that these features may or may not be formed. The adhesive element 68 is also applied and may, in some embodiments, be formed as a ring.

[0042] Next, as in Fig. The heat sink 70 is shown positioned and pressed down. Although only one heat sink 70 is shown, there can be multiple heat sinks 70, each positioned on one of the package components 22. The heat sink 70 is in physical contact with and attached to the TIMs 64 on one of the package components 22. In accordance with some embodiments, the heat sink 70 comprises an upper section 70A, the underside of which is planar and contacts the TIMs 64. The heat sink 70 may (or may not) include a lower section 70B that extends downward to connect the adhesive elements 68. Furthermore, the heat sink 70 includes a heat sink strip 70D that extends from the underside of the upper section 70A into the gap between adjacent packages 32. The sections 70A, 70B, and 70D can be parts of one and the same integrated area without any interface between them.During the application of the heat sink 70, it is pressed downwards against the adhesive element 66B (and 66A, if present) and the adhesive elements 68 and TIMs 64 to ensure physical contact with these features.

[0043] The heat sink rod 70D is inserted into the adhesive element 66B. The heat sink rod 70D has a narrower width than the distance between the packages 32, allowing the adhesive element 66B to be compressed and extend up to the side walls of the heat sink rod 70D. The top surface of the resulting adhesive element 66B can be higher than, level with, or lower than the top surface of the package 32. This increases the contact area between the adhesive element 66B and the heat sink strip 70D, ensuring good adhesion. However, an air gap 71 can remain between the adhesive surface 66B and the upper part 70A of the heat sink 70D. The volume of the applied adhesive element 66B must therefore take into account the volume of the heat sink strip 70D. Maintaining a certain air gap provides some processing leeway, preventing the adhesive element 66B from being pressed against the top surfaces of the TIMs 64.

[0044] A curing process is then carried out to solidify the adhesive elements 66 and 68. The curing process can be performed at a similar temperature and for a similar curing time as described in the preceding embodiments. After the curing process, the package component 22 can be detached from the carrier 10, followed by the formation of the solder areas 72. The package component 20 can then be sawn to separate the package component 22 from each other, forming packages 74, as described in the Fig. 10A and Fig. 10B shows the cross-sections AA and BB respectively in Fig. 12 represent.

[0045] The adhesive element 66B does not directly attract the upper part 70A, but rather exerts a force on the heat sink rod 70D, which in turn pulls the upper part 70A towards the package substrate 22. This reduces delamination between the TIMs 64 and the packages 32. In some embodiments, adhesive elements 66A are also formed to further reduce delamination.

[0046] Fig. Figure 74 shows a package in accordance with some embodiments. The structures, materials, and manufacturing processes according to these embodiments are essentially the same as in the Fig. 8, Fig. 9, Fig. 10A and Fig. 10B, except that the heat sink 70 also has fins 70C. The fins 70C can be glued to the upper part 70A by another TIM or be an integrated part of the heat sink 70.

[0047] The Fig. 12, Fig. 13 to Fig. Figure 14 shows the top view of some components of Packages 74 according to some embodiments of the present disclosure. Fig. Figure 1 illustrates an embodiment in which the adhesive elements 66A are formed in areas surrounding the package 32. For example, some adhesive elements 66A can be formed near the areas where the memory stacks 46B are located close together. The adhesive element 66B can be distributed between two packages 32. The heat sink strip 70D may or may not be formed, and if it is formed, it is configured as an elongated strip that can extend over the entire length of the space between the packages 32 or substantially over the entire length (e.g., more than about 80 percent of the length) of the space between the packages 32.

[0048] Fig. Figure 1 shows an embodiment in which the adhesive elements 66A are formed near the corners of the packages 32, i.e., in the areas where delamination is more likely. If the memory stacks 46B are located close together (and thus the molding compounds are in contact with the TIMs 64), the adhesive elements 66A can extend into the spaces between adjacent memory stacks 46B. The adhesive surface 66B can be arranged between two packages 32. The heat sink strip 70D can be molded or unmolded, and if molded, it is formed as an elongated strip that can extend over the entire length of the space between the packages 32 or substantially over the entire length (e.g., more than about 80 percent of the length) of the space between the packages 32.

[0049] Fig. Figure 1 shows an embodiment in which the adhesive elements 66A are configured as a ring that completely encloses the packages 32. The adhesive element 66B can be placed between two packages 32. Either one end or both ends of the adhesive element 66B can be physically separated from the adhesive element 66A as separate features, or alternatively, either one end or both ends of the adhesive element 66B can be physically connected to the adhesive element 66A. The heat sink 70D can be formed or unformed, and if formed, it can be inserted into the adhesive element 66B but not into the adhesive element 66A, according to some embodiments. According to alternative embodiments, the heat sink rod 70D can be inserted into both the adhesive element 66B and the adhesive element 66A. In accordance with these embodiments, the heat sink extends beyond the space between the packages 32.

[0050] In each of the Fig. 12, Fig. 13 and Fig. In the 14 illustrated embodiments, the adhesive elements 66A and 66B can be configured in various combinations. According to some embodiments, the adhesive elements 66A are formed, while the adhesive element 66B is not. According to alternative embodiments, the adhesive elements 66B are formed, while the adhesive elements 66A are not. In still other embodiments, both the adhesive elements 66A and the adhesive elements 66B are formed. If the adhesive element 66B is formed, a heat sink strip 70D may or may not be present, according to various embodiments.

[0051] By using the embodiments of this disclosure, the warpage of the packages and delamination can be reduced. The embodiments can be applied to large packages, for example, with a length and width greater than 50 mm or 75 mm. Experiments were carried out to produce a first sample package without adhesive elements 66A and a second sample package with adhesive elements 66A. The coplanarity values ​​of the first and second sample packages were measured. A coplanarity value of 0 means no warpage, and the larger the coplanarity value, the greater the warpage. The coplanarity of the first sample package is 293 µm, while the coplanarity of the second sample package is reduced to 264 µm. Accordingly, the warpage is reduced by approximately 9.8% by the embodiments of this disclosure.Furthermore, the TIM coverage of the second sample package is also better than that of the first sample package. TIM coverage indicates what percentage of the TIM area intended to adhere to the underlying features actually adheres to them without delamination, with 100 percent meaning no delamination. The TIM coverage of the first sample package is between approximately 94 percent and 95 percent, while the TIM coverage of the second sample package is improved to between approximately 98 percent and 99 percent.

[0052] Furthermore, the test results showed that the heat sink strip can help reduce warpage. This may be due to the reinforcement of the heat sink (and the resulting package) resulting from the additional thickness in a portion of the heat sink, and possibly also to the tensile force exerted by the adhesive element 66B. Experiments are being conducted to create a third sample package without the heat sink rod 70D and a fourth sample package with the heat sink rod 70D. The heat sink coplanarity in the third sample package is 140 µm, while the coplanarity of the heat sink in the fourth sample package is reduced to 125 µm. Additionally, the TIM coverage of the third sample package is between approximately 94 percent and approximately 95 percent, and the TIM coverage of the fourth sample package is improved to 99 percent.

[0053] In the embodiments described above, some methods and features are discussed in accordance with some embodiments of the present disclosure for forming a three-dimensional (3D) package. Other features and methods may also be included. For example, test structures may be provided to support the inspection of the 3D package or the 3DIC components. The test structures may include, for example, test pads formed in a redistribution layer or on a substrate that enables the inspection of the 3D package or the 3DIC, as well as the use of test probes and / or test cards and the like. The verification test may be performed on both intermediate structures and the final structure.Furthermore, the structures and procedures disclosed herein can be used in conjunction with testing procedures that include intermediate testing of known good dies to increase yield and reduce costs.

[0054] The embodiments of the present disclosure have several advantageous properties. The use of adhesive elements reduces the delamination of the TIMs from the underlying features. Warpage of the package is also reduced. The formation of the heat sink strip also contributes to the reduction of delamination and warpage.

[0055] According to some embodiments of the present disclosure, a method comprises bonding a first package and a second package via a package component; adhering a first TIM and a second TIM over the first and second packages, respectively; applying a first adhesive element to the package component; arranging a heat sink over and in contact with the first adhesive element, wherein the heat sink comprises a section over the first TIM and the second TIM; and curing the first adhesive element. According to one embodiment, the method further comprises applying an underfill between the first package and the package component, wherein the first adhesive element further comprises an additional section that overlaps and contacts the underfill. According to one embodiment, the first adhesive element has a lower modulus value than the underfill material.According to one embodiment, at a first time point after the application of the first adhesive element and before the curing of the first adhesive element, the first adhesive element has a first upper surface that is higher than a second upper surface of the first TIM. According to another embodiment, at a second time point after the attachment of the heat sink, the first adhesive element has a third upper surface that is coplanar with the second upper surface of the first TIM. According to another embodiment, the first adhesive element is applied to a first side of the first package, and the second package is located on a second side of the first package, opposite the first side. In another embodiment, the method further comprises applying a second adhesive element to the package component, wherein the second adhesive element has a first upper surface that is lower than a second upper surface of the first TIM.In one embodiment, the heat sink comprises an upper section that is taller than the first and second TIMs, and a heat sink rod that extends from a lower surface of the upper section into a space between the first and second packages, the heat sink rod being inserted into the second adhesive element. In another embodiment, the method further comprises applying an adhesive ring that surrounds the first and second packages, the heat sink comprising a lower section that contacts the adhesive ring. In another embodiment, the first adhesive element comprises a base material and filler particles mixed into the base material. In another embodiment, the first and second TIMs are pre-formed solid TIMs when bonded over the first and second packages, respectively.

[0056] According to some embodiments of the present disclosure, a package comprises a package component; a first package and a second package bonded over the package component; a first TIM and a second TIM over the first package and the second package, respectively; a first adhesive element on the package component; and a heat sink over and in contact with the first adhesive element, the heat sink further being located over the first TIM and the second TIM. According to one embodiment, the heat sink is in physical contact with the first TIM and the second TIM. According to one embodiment, the first adhesive element comprises non-straight sidewalls. According to one embodiment, the package further comprises an underfill between the first package and the package component, wherein a first portion of the first adhesive element is located over and in contact with a second portion of the underfill.According to one embodiment, the package further comprises a second adhesive element on the package component, wherein the second adhesive element is located between the first package and the second package and is separated from the heat sink by an air gap. According to one embodiment, the heat sink comprises an upper section that is higher than the first TIM and the second TIM, and a heat sink rod extending from a bottom surface of the upper section, the heat sink rod extending into the second adhesive element.

[0057] According to some embodiments of the present disclosure, a package comprises a package substrate; a package component located above and bonded to the package substrate, the package component comprising an interposer; a device chip located above and bonded to the interposer; a lid comprising an upper section above the package component; and an adhesive element between the lid and the package substrate and in physical contact with them, wherein a first upper surface of the adhesive element is higher than a second upper surface of the package component. According to one embodiment, the package further comprises a thermal interface material between and in physical contact with the package component and the lid.According to one embodiment, the package further comprises an underfill between the package component and the package substrate, wherein the package component comprises a molding compound with which the device shape is formed, and wherein the adhesive element is softer than both the molding compound and the underfill.

Claims

[1] Procedure encompassing: Bonding of a first package (32) and a second package (32) over a package component (20, 22, 34, 46, 46A-C); Applying a first thermal interface material, TIM , (64) and a second TIM (64) over the first and second package (32), respectively; After the first TIM (64) and the second TIM (64) have been glued on, a first adhesive element (66, 66A, 66B, 68) is applied to the package component (20, 22, 34, 46, 46A-C); Arranging a heat sink (70) over the first adhesive element (66, 66A, 66B, 68) and in contact with it, wherein the heat sink (70) comprises a section (70A) above the first TIM (64) and the second TIM (64); and Curing of the first adhesive element (66, 66A, 66B, 68), wherein at a first time point after the application of the first adhesive element (66, 66A, 66B, 68) and before the curing of the first adhesive element (66, 66A, 66B, 68) the first adhesive element (66, 66A, 66B, 68) has a first upper surface which is higher than a second upper surface of the first TIM (64), and the first adhesive element (66, 66A, 66B, 68) is in physical contact with the package component (20, 22, 34, 46, 46A-C). [2] Method according to claim 1, wherein the first adhesive element (66, 66A, 66B, 68) is spaced apart from the first package (32) and the second package (32). [3] Method according to claim 1 or 2, further comprising the application of an underfill (44, 54) between the first package (32) and the package component (20, 22, 34, 46, 46A-C), wherein the first adhesive element (66, 66A, 66B, 68) has a lower modulus value than the underfill (44, 54). [4] Method according to one of the preceding claims, wherein at a second time after the application of the heat sink (70) the first adhesive element (66, 66A, 66B, 68) has a third upper surface which is coplanar with the second upper surface of the first TIM (64). [5] Method according to one of the preceding claims, wherein the first adhesive element (66, 66A, 66B, 68) is applied to a first side of the first package (32) and the second package (32) is arranged on a second side of the first package (32) opposite the first side. [6] Method according to any of the preceding claims, further comprising the application of a second adhesive element (66, 66B, 68) to the package component (20, 22, 34, 46, 46A-C), wherein the second adhesive element (66, 66B) has a first upper surface which is lower than a second upper surface of the first TIM (64). [7] Method according to claim 6, wherein the heat sink (70) comprises: an upper section (70A) that is higher than the first TIM (64) and the second TIM (64); and a heat sink rod (70D) extending from a bottom surface of the upper section (70A) into a space between the first package (32) and the second package (32), wherein the heat sink rod (70D) is inserted into the second adhesive element (66, 66B). [8] Method according to any of the preceding claims, further comprising the application of an adhesive ring surrounding the first package (32) and the second package (32), wherein the heat sink (70) comprises a lower section (70B) that contacts the adhesive ring. [9] Method according to any of the preceding claims, wherein the first adhesive element (66, 66A, 66B, 68) comprises a base material and filler particles mixed into the base material. [10] Method according to any of the preceding claims, wherein the first TIM (64) and the second TIM (64) are preformed solid TIMs (64) when they are glued over the first package (32) and the second package (32), respectively. [11] Package (32) which includes the following: a package component (20, 22, 34, 46, 46A-C); a first package (32) and a second package (32) that are bonded via the package component (20, 22, 34, 46, 46A-C); a first thermal interface material, TIM (64), and a second TIM (64) over the first package (32) and the second package (32), respectively; a first adhesive element (66, 66A, 66B, 68) on the package component (20, 22, 34, 46, 46A-C); and a heat sink (70) which is arranged above and in contact with the first adhesive element (66, 66A, 66B, 68), wherein the heat sink (70) is further arranged above the first TIM (64) and the second TIM (64); an underfill (44, 54) arranged between the first package (32) and the package component (20, 22, 34, 46, 46A-C), wherein a first section of the first adhesive element (66, 66A, 66B, 68) is arranged over and contacts a second section of the underfill (44, 54); and / or a second adhesive element (66, 66B) on the package component (20, 22, 34, 46, 46A-C), wherein the second adhesive element (66, 66B) is arranged between the first package (32) and the second package (32) and is separated from the heat sink (70) by an air gap (67, 71). [12] Package (32) according to claim 11, wherein the heat sink (70) is in physical contact with the first TIM (64) and the second TIM (64). [13] Package (32) according to claim 11 or 12, wherein the first adhesive element (66, 66A, 66B, 68) has odd side walls. [14] Package (32) according to any one of claims 11 to 13, wherein the heat sink comprises: an upper section (70A) that is higher than the first TIM (64) and the second TIM (64); and a heat sink rod (70D) extending from a bottom surface of the upper section (70A), the heat sink rod (70D) extending into the second adhesive element (66, 66B). [15] Package (74) which includes the following: a package substrate (20, 22); a package component (32) that is arranged above the package substrate (20, 22) and so that it is bonded, with the package component (32) having the following features: an interposer (34); and a device die (46, 46A-C) arranged above the interposer (34) and so that it is bonded; a lid (70) having an upper section (70A) arranged above the package component (32); and an adhesive element (66, 66A, 66B, 68) that is arranged between the lid (70) and the package substrate (20, 22) and is in physical contact with it, wherein a first upper surface of the adhesive element (66, 66A, 66B, 68) is higher than a second upper surface of the package component (32), a thermal interface material, TIM (64), which is located between the package component (32) and the cover (70) and is in physical contact with it. [16] Package (74) according to claim 15, further comprising an underfill (44, 54) arranged between the package component (32) and the package substrate (20, 22), wherein the package component (32) comprises a molding compound (62) surrounding the device die (46, 46A-C), and wherein the adhesive element (66, 66A, 66B, 68) is softer than both the molding compound (62) and the underfill (44, 54).

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