A heat sink for dissipating heat from an electronic device using a layer of liquid thermal interface material

Abstract

The present disclosure describes a heat sink with a liquid storage structure. An electronic device using the heat sink can form a liquid storage system that reliably provides a liquid thermal interface material layer to the gap between the heat sink and the electronic device. The liquid storage structure includes a seal ring, one or more connection holes, and a liquid reservoir. The liquid reservoir includes a port to the atmosphere that can use the pressure of the ambient atmosphere to drive the flow of liquid in the liquid reservoir, thereby ensuring that the sealed gap between the electronic device and the heat sink sealed by the seal ring is always filled with liquid thermal interface material without creating high pressure.

Description

Technical Field

[0001] This disclosure generally relates to a heat sink for dissipating heat from an electronic device; more particularly to a cover over a chip, wherein a liquid thermally conductive interface material layer is used to allow a reverse chip package using this cover. Background Technology

[0002] In a flip-chip package where the semiconductor chip is the heat sink, a thermal interface material layer (TIM) is typically used to fill the gap between the flip-chip and the heat sink, which can be a cover over the chip or a heatsink. Types of TIMs generally include thermal pads, thermal pastes, phase change material thermal pads, metal soldering materials, and liquid metals. A good TIM needs to have the following characteristics: 1) high thermal conductivity, 2) good surface wetting ability to reduce contact thermal resistance, 3) good gap-filling ability, and 4) good reliability in testing and long-term applications. Liquid metals used as TIMs typically include gallium and gallium alloys. Gallium has a melting point of approximately 29°C, and its alloys can have even lower melting points. Liquid metals have a much higher thermal conductivity than commonly used thermal pads and thermal pastes, and their surface wetting and gap-filling abilities are excellent. Therefore, considering the first three characteristics, liquid metals are a very ideal TIM material. Compared to other thermal interface materials, liquid metal could significantly reduce chip temperature if used as a thermal interface material layer in capped inverted chip packages. However, when capped inverted chip packages undergo thermal cycling tests or long-term use, temperature changes cause chip warping, resulting in changes in the volume of the gap between the cap and the chip. This can cause the liquid metal, serving as the thermal interface material layer, to be squeezed out. Because liquid metal is easily squeezed out, it cannot be used as a thermal interface material in traditional capped inverted chip packages. Once squeezed out, one consequence is incomplete filling of the gap between the chip and the cap, reducing the thermal conductivity of the thermal interface material layer; more importantly, due to the conductivity of liquid metal, leakage could damage the entire electronic device. Therefore, liquid metal has not yet been commercially used as a thermal interface material layer in capped inverted chip packages. Generally, for similar reasons, liquid metal is not commercially used as a thermal interface material layer between heat sinks (such as heat sinks) and heat generators (such as chips). Summary of the Invention

[0003] To overcome the problem of liquid metal extrusion as a thermal interface material layer, this invention discloses a heat sink or cover with a liquid storage structure for inverted chip packaging, which is briefly described below.

[0004] A heat sink that allows the use of a liquid thermal interface material layer in an electronic device includes: a substrate with upper and lower surfaces and a liquid storage structure, wherein the liquid storage structure includes a liquid reservoir, a sealing ring, and a connecting hole. The liquid reservoir is a liquid storage space contained within the substrate; the sealing ring is disposed on the lower surface of the substrate; the electronic device includes an upper surface; the upper surface of the electronic device and the lower surface of the substrate form a gap; the sealing ring seals the gap from its periphery, forming a sealed gap; and one end of the connecting hole leads to the sealed gap. One end leads to the reservoir, and the connecting hole connects the sealed gap and the reservoir. A liquid material fills the sealed gap and partially fills the reservoir, which includes an opening to the atmosphere. When the volume of the sealed gap decreases, the liquid material can be squeezed into the remaining space in the reservoir, thus preventing the liquid pressure in the sealed gap from increasing. When the volume of the sealed gap increases, the liquid in the reservoir can flow into the sealed gap under ambient atmospheric pressure, thus keeping the sealed gap always full of liquid. The heat sink includes a lid for a capped inverted chip package, a heat sink for heat dissipation of the electronic device, and a thermal chamber.

[0005] A capped inversion chip package comprising a liquid thermally conductive interface material layer includes: an inversion chip package consisting of an inversion chip and a substrate, and a cap including a liquid reservoir structure. The cap includes a top plate and a sidewall. The top plate includes an upper surface and a lower surface. The cap is adhered to the substrate via its sidewall, and the top plate covers the inversion chip. The inversion chip includes an upper surface, and the lower surface of the top plate forms a gap with the upper surface of the inversion chip. The liquid reservoir structure includes a reservoir, a sealing ring, and a connection hole. The reservoir is a liquid storage space contained within the top plate, and the sealing ring is disposed on the lower surface of the top plate. A ring seals the gap from its periphery, forming a sealed gap. One end of the connecting hole leads to the sealed gap, and the other end leads to the reservoir, thus connecting the sealed gap and the reservoir. A liquid material fills the sealed gap and partially fills the reservoir, which includes an opening to the atmosphere. When the volume of the sealed gap decreases, the liquid material therein can be squeezed into the remaining space in the reservoir, thereby preventing the liquid pressure in the sealed gap from increasing. When the volume of the sealed gap increases, the liquid in the reservoir can flow into the sealed gap under the pressure of the ambient atmosphere, thereby keeping the sealed gap always filled with liquid.

[0006] The features and advantages of this disclosure will become more apparent below through a detailed description of the embodiments in conjunction with the accompanying drawings. It should be noted that the drawings and related descriptions are merely illustrative of embodiments of this disclosure and do not limit the scope of the claims. Attached Figure Description

[0007] Figure 1 This is a schematic diagram illustrating a conventional cap used in a capped inverted chip package; Figure 2 This is a schematic diagram illustrating a traditional heat dissipation method for a capped inverted chip package; Figure 3 This is a schematic diagram used to illustrate the basic ideas and features of the present invention; Figure 4 and Figure 4A This is a schematic diagram illustrating how, in one embodiment of the present invention, a capped inverted chip package containing a liquid thermally conductive interface material layer is formed using the cap of the present invention. Figure 5 , Figure 5A and Figure 5B This is a schematic diagram illustrating a cross-sectional view, a top view, and a bottom view of a lid including a liquid storage structure in one embodiment of the present invention, wherein the liquid reservoir in the liquid storage structure is a spiral tunnel constructed on the upper surface of the lid top plate, and the lid further includes a removable top plate. Figure 6 and Figure 6A These are schematic cross-sectional and top views illustrating some alternative designs of a reservoir in a lid containing a reservoir structure in one embodiment of the present invention; Figure 7 and Figure 7A These are schematic cross-sectional and top views illustrating some alternative designs of a reservoir in a lid containing a reservoir structure in another embodiment of the invention; Figure 8 and Figure 8A This is a schematic diagram illustrating a capped inverted chip package employing a cap containing a liquid reservoir structure in one embodiment of the present invention, wherein the liquid reservoir is a spiral tunnel constructed on the upper surface of the cap top sheet; Figure 9 , Figure 9A , Figure 9B and Figure 9C This is a schematic diagram illustrating a cross-sectional view, a top view, and a bottom view of a lid including a liquid storage structure in one embodiment of the present invention, wherein the liquid reservoir in the liquid storage structure is a tunnel constructed on the lower surface of the lid top plate and surrounding a sealing ring; Figure 10 This is a schematic diagram illustrating a capped inverted chip package employing a cap including a liquid reservoir structure in one embodiment of the present invention, wherein the liquid reservoir in the liquid reservoir structure included in the cap is a tunnel constructed on the lower surface of the cap top sheet and surrounding a sealing ring; Figure 11 This is a schematic diagram illustrating a cover including a liquid storage structure in one embodiment of the present invention, wherein the liquid reservoir in the liquid storage structure included in the cover is a tunnel surrounding a sealing ring in the middle region of its top plate; Figure 12 This is a schematic diagram illustrating a cover including a liquid storage structure in one embodiment of the present invention, wherein the liquid reservoir in the liquid storage structure included in the cover is a tube outside its top plate; Figure 13 and 13A This is a schematic diagram illustrating that, in one embodiment of the present invention, a cover containing a liquid storage structure may consist of multiple connecting holes and multiple tunnels, and the geometry of the tunnels surrounding the sealing ring may be a spiral form containing a folded structure. Figure 14 This is a schematic diagram illustrating a reverse chip package containing a multi-chip module, wherein the multi-chip module can be regarded as a single reverse chip and the cap containing the liquid storage structure of the present invention is used to form a capped multi-chip module reverse chip package. Figure 15 15A and 15B are schematic diagrams illustrating a cap containing a liquid storage structure in one embodiment of the present invention, corresponding to a capped inverted chip package containing multiple chips. Figure 16 This is a schematic diagram illustrating a heat dissipation structure in one embodiment of the present invention, which is a heat sink containing a liquid storage structure and a reverse chip package forming a heat dissipation structure containing a liquid thermal interface material layer. Figure 17 This is a schematic diagram illustrating some basic features of a heat sink containing a liquid storage structure in one embodiment of the present invention; Figures 18 to 21 This is a schematic diagram illustrating the assembly steps of assembling a heat sink containing a liquid storage structure with an electronic device to form a liquid thermally conductive interface material layer in one embodiment of the present invention. Figure 22 and Figure 23 This is a schematic diagram used to illustrate the problem described in this invention and the physical principles used to solve this problem; Figure 24 and Figure 25This is a schematic diagram illustrating some optional designs of the annular groove and connecting hole in the substrate of the heat sink in some embodiments of the present invention; Figure 26 , Figure 27 and Figure 28 This is a schematic diagram illustrating that, in some embodiments of the present invention, the heat sink containing the liquid storage structure is a heat sink fin, wherein... Figure 26 This illustrates mounting the heat sink onto the upper surface of a chip within a flip-chip package, forming a liquid thermal interface material layer. Figure 27 This illustrates the optional sealing ring designs, and Figure 28 The illustration shows the heat sink being mounted on the upper surface of the cover of a capped inverted chip package, forming a liquid thermal interface material layer. Figure 29 and Figure 30 This is a schematic diagram illustrating that, in some embodiments of the present invention, the heat sink including the liquid storage structure is a cold plate, wherein... Figure 29 This illustration demonstrates how a traditional cold plate dissipates heat from a heat source through a traditional thermally conductive interface material layer. Figure 30 This is used to illustrate a method by which a cold plate containing a liquid storage structure dissipates heat from a heat source through a liquid thermal interface material layer. Figure 31 , Figure 32 and Figure 33 This is a schematic diagram illustrating that, in some embodiments of the present invention, the heat sink including the liquid storage structure is a heat exchange chamber, wherein... Figure 31 Used to illustrate a conventional heat exchange chamber Figure 32 This is used to illustrate a heat exchange chamber containing a liquid storage structure. Figure 33 A bottom view illustrating the cold plate of the heat exchange chamber containing the liquid storage structure. Detailed Implementation

[0008] Figure 1 and Figure 2 This is used to explain some terms related to caps, capped inverted chip packages, thermal interface material layers, and the challenges encountered by existing technologies in using liquid thermal interface material layers in capped inverted chip packages. Figure 1 This is a schematic diagram illustrating the conventional cap used in a capped inverted chip package. Figure 1The numerical symbol 1000 represents several examples of conventional covers, where 100 represents a typical conventional cover including a top plate 101 and a sidewall 102, 110 represents another conventional cover further including stepped structures 111 and 112 for a specific application, and 120 represents a conventional hat-shaped cover where the sidewall further includes a foot edge 121. The numerical symbols 103 and 104 in cover 100 represent the upper and lower surfaces of the cover. Most conventional covers used in inverted chip packages with covers are made of copper. Figure 1 The traditional lids shown in the diagram are not fundamentally different in structure; they all basically consist of a top plate and a side wall.

[0009] Figure 2 This is a schematic diagram illustrating how a conventional capped inverted chip package dissipates heat through a heat sink. Figure 2The numerical symbol 1100 represents a conventional capped inverted chip package with a heat sink, where 140, 150, and 160 represent a heat sink, a cap, and an inverted chip package, respectively. The inverted chip package 160 consists of an inverted chip 161 and a circuit board 162, wherein the inverted chip 161 is attached to the middle portion of the upper surface of the circuit board 162 by solder balls and a layer of filler material 163. It should be noted that, for simplicity and clarity, the same numerical symbols in different figures in the graphical description of this disclosure will represent the same components. A conventional capped inverted chip package consists of an inverted chip package 160 and a cap 150, wherein the cap 150 has its sidewalls bonded to the peripheral area of ​​the upper surface of the circuit board by an adhesive layer 152, while the top of the cap covers the inverted chip 161, and a thermally conductive interface material layer 151 is used to fill the gap between the inverted chip 161 and the cap 150. A heat sink 140 is mounted on the upper surface of a cover 150 to dissipate heat generated by the inverting chip 161 into the environment. A thermal interface material layer 141 is used to fill the cover 150 and the heat sink 140. Thermal interface material layers 151 and 141 are commonly referred to as thermal interface material layer 1 and thermal interface material layer 2. Liquid thermal interface material layers have not been commercially adopted due to extrusion problems caused by thermal cycling. Commonly used thermal interface material layers are usually thermal paste or thermal pads. It should be noted that the inverting chip 161 and the cover 150 are not always flat. Due to the mismatch in the coefficient of thermal expansion between the chip 161 and the circuit board 162, the surfaces of the chip and the cover will warp to varying degrees with temperature changes. This warping will cause changes in the volume of the gaps between the chip and the cover, and between the cover and the heat sink. This volume change will extrude the liquid thermal interface material layer, thus making it difficult to use liquid thermal interface material layers when heat dissipating chip packages.

[0010] Figure 3 This is a schematic diagram used to illustrate the basic ideas and features of the present invention. Figure 3The numerical symbol 2000 in the diagram indicates a cap 200 and a corresponding capped inverted chip package 220. The cap 200 comprises a liquid reservoir structure consisting of a reservoir 212, a sealing ring 211, and a connection hole 213, while the capped inverted chip package 220 comprises a liquid reservoir system based on said liquid reservoir structure. In addition to the top plate 201 and sidewalls 202, the cap 200 now includes a liquid reservoir structure consisting of a sealing ring 211 mounted on the lower surface of the cap top plate, a reservoir 212 in the cap top plate, and a set of connection holes. One end of the connection hole 213 is located in the area surrounded by the sealing ring on the lower surface of the cap top plate, while the other end is connected to the reservoir 212, which has an opening to the atmosphere. For clarity, see reference... Figure 3 First, some terms and concepts will be explained. The connection hole 213 has two ports, one located on the lower surface of the cap top plate, called the inner port, and the other port connected to the reservoir 212, called the outer port. The sealing ring 211 divides the lower surface of the cap top plate into two regions, the portion surrounded by the sealing ring being called the sealing ring region of the lower surface of the cap top plate. Similarly, the cap top plate is also divided into two regions by the sealing ring, the portion from the lower surface to the upper surface of the top plate located inside the sealing ring being called the inner region of the cap top plate, and the portion located outside the sealing ring being called the peripheral region of the cap top plate. The reservoir 212 of this disclosure can generally be a container that can absorb or release liquid as needed using atmospheric pressure, and in some embodiments of the invention, it is constructed as one or more cavities or tunnels in the cap top plate. Figure 3 The numerical symbol 214 associated with the reservoir 212 in the middle cover 200 represents an opening of the reservoir 212 to the atmospheric environment. Its purpose is to use the atmospheric pressure in the environment to drive the flow of liquid in the reservoir 212 to achieve the formation of a required liquid thermal interface material layer in the capped inverted chip package.

[0011] refer to Figure 3 In section 220, after assembling the cap 200 of the present invention with the inverted chip package 160 and filling it with liquid material, the capped inverted chip package 220 of the present invention is manufactured. The capped inverted chip package 220 is characterized by comprising a liquid storage system formed based on the liquid storage structure 200 contained in the cap, which consists of a liquid reservoir 212 in the cap, a connecting hole 213, a sealing gap 222 between the cap 200 and the chip 161, and liquid material 222A / 212A. The sealing gap 222 is formed by sealing the gap between the cap 220 and the chip 161 at the edge of the chip using a sealing ring 211. Figure 3The lid shown in the diagram contains a reservoir 212, which is a cavity in the top plate of the lid. Generally, the reservoir in this invention can be a container outside the hermetically sealed gap 222. The connection hole 213 connects the hermetically sealed gap 222 and the reservoir 212. A liquid material, which can be used as a thermally conductive interface material layer, fills the hermetically sealed gap 222 and partially fills the reservoir 212. The numerical symbols 222A and 212A represent the liquid material filled in the hermetically sealed gap 220 and the reservoir 212, respectively, wherein the liquid material 222A forms a liquid thermally conductive interface material layer between the chip 161 and the lid 220. It should be noted that when the capped inverted chip package 220 undergoes thermal cycling testing or long-term use, temperature changes will cause the chip to warp and the degree of warping to change, thus the volume of the gap 222 between the lid and the chip also changes with temperature. The reservoir 212 includes an opening 214 leading to the atmosphere. When the volume of the sealed gap 222 decreases, the liquid material 222A therein can be squeezed into the remaining space 212B in the reservoir, thereby preventing the liquid pressure in the sealed gap from increasing. When the volume of the sealed gap 222 increases, the liquid 212A in the reservoir can flow into the sealed gap 222 under the pressure of the ambient atmosphere, thereby keeping the sealed gap 222 always filled with liquid.

[0012] It should be emphasized that, unlike existing technologies, the liquid reservoir described in this invention includes a... Figure 3The opening to the atmosphere, indicated by the numerical symbol 214, allows the liquid 212A in the reservoir 212 and the liquid 222A in the sealed gap 222 to flow freely between each other via the connecting hole 213, utilizing the ambient atmospheric pressure as the volume of the sealed gap 222 increases or decreases. This ensures that the sealed gap 222 is always filled with liquid while preventing the liquid pressure within it from rising. It can be seen that if only a sealing ring 211 is used, when the volume of the sealed gap 222 decreases, the pressure of the liquid 222A within it will increase, potentially causing damage to the sealing ring. Conversely, when the volume of the sealed gap 222 increases, the liquid 222A will be insufficient to fill the enlarged sealed gap, resulting in a decrease in thermal conductivity. It should be noted that the material selection, size, and configuration design of the sealing ring 211 can be flexibly adjusted as needed. Essentially, the material of the sealing ring 211 should be selected to withstand the temperatures experienced by electronic products and possess excellent elasticity. A rubber-type material is a preferred material for the sealing ring 211. It should be noted that in the capped inverted chip package of the present invention, the sealing ring 211 is in a compressed state, as shown in the original state of the sealing ring in 200 and the compressed state of the sealing ring shown in 211A in 220. Furthermore, due to the low insertion performance of the sealing ring, the sealing ring 211 should occupy as little surface area of ​​the chip as possible while ensuring a seal. As shown in W in 200, the width of a sealing ring covering the edge area of ​​the chip's upper surface can preferably be set to 0.2 mm to 1 mm, which can be determined according to specific circumstances. Alternatively, the sealing ring can also be designed on the side of the chip, i.e., sandwiched between the cap and the circuit board and wrapping around the side of the chip, thereby requiring little or no space on the chip's upper surface.

[0013] refer to Figure 3 How to ensure that the liquid fills the sealed gap 222 and partially fills the reservoir 212 in the capped inverted chip package 222 of the present invention without forming bubbles in the liquid is a problem that needs to be solved. Figure 4 This is a schematic diagram illustrating a method for solving this problem in one embodiment of the present invention, wherein the numerical symbol 250 represents a lid, which is Figure 3The cap 200 shown has a pre-filled liquid material 252 in its reservoir 212. To prevent leakage of the liquid material 252 during the movement or application of the cap 250, a low-melting-point sealing material 252A is used to seal the inner port of the connection hole. 260 represents an adhesive material placed on the edge region of the circuit board to bond the cap to the circuit board. 270 represents the cap 250 being pressed onto the circuit board in a vacuum environment while the sealing ring 211A is compressed, thus sealing the gap 222 as a vacuum gap sealed by the sealing ring 211A. The entire assembly 270 then undergoes a high-temperature curing step to cure the adhesive layer 253A. In this high-temperature curing step, the environment of the entire assembly 270 is no longer a vacuum, so that at high temperature, as the sealing material 252A melts, the ambient gas gradually forces the liquid 252 in the reservoir into the sealed gap 222 until it is filled, thus forming a... Figure 3 The image shows a capped inverted chip package with a liquid thermally conductive interface material layer. (Image 220) Figure 4 In the method described, the liquid material 252 can be gallium or a gallium alloy with a melting point below room temperature, while the sealing material 252A can be a gallium alloy or an indium alloy with a melting point above room temperature, and its melting point can be set between 60°C and 100°C. It should be noted that pure gallium or indium alloys with a melting point above room temperature (25°C) can also be used. 0 C) uses a gallium alloy as the liquid material 252, thus eliminating the need for a sealing material 252A. It should be noted that when using pure gallium or a gallium alloy with a melting point above room temperature as the liquid material 252, the cap 250 containing this material must not be exposed to high temperatures before application to ensure that the material 252 in the cap reservoir is solid, thus eliminating concerns about leakage. Additionally, Figure 4A The numeral 2600 indicates another alternative method for filling a capped inverted chip package with liquid metal, characterized in that a solid metal film, such as a pure gallium or gallium alloy film, is first placed in a region surrounded by a sealing ring on the lower surface of the cap top sheet at a low temperature, and the film avoids covering the connection hole 213. Then, under conditions below the melting point of the solid pure gallium or gallium alloy, as shown in the figure... Figure 4 As shown, the cap 260 containing the thin film is placed on the inverted chip package 160, and then the adhesive material 253A of the cap is cured by raising the temperature in a vacuum environment, so that the cap is bonded to the circuit board. At the same time, when the temperature rises, the solid pure gallium or gallium alloy thin film 261 will be melted, a part of which will remain in the sealed gap 222 to form a liquid metal thermal interface material layer, and the excess part will be squeezed into the reservoir 212.

[0014] It should be noted that, Figure 3 The illustrated cap 200, including the reservoir 212 and its corresponding capped inverted chip package 220, can be flexibly designed according to specific circumstances. In some embodiments of the invention, constructing a tunnel-like reservoir within the cap is a preferred solution to prevent air from entering the sealed gap. The following... Figures 5 to 13 These are schematic diagrams illustrating caps comprising tunnel-shaped reservoirs and their corresponding capped inverted chip packages in some embodiments of the invention. Some preferred reservoir structures include tunnel-shaped reservoirs formed by tunnel-shaped grooves on the upper or lower surface of the cap top sheet, tunnel-shaped reservoirs formed in an intermediate layer of the cap top sheet, and tubular containers outside the cap top sheet.

[0015] Figure 5 , Figure 5A and Figure 5B This is a schematic diagram illustrating a cross-sectional view, a top view, and a bottom view of a lid in a preferred embodiment of the invention, wherein the reservoir in the lid is constructed based on a groove on the upper surface of the lid top plate; in particular, the groove is a spiral groove. Figure 5 The numerical symbol 3000 in the figure represents a cross-sectional view of the lid, where 300 and 310 represent the top plate and sidewall of the lid, respectively; 305 and 306 represent an annular groove on the lower surface of the top plate and a sealing ring installed in the annular groove, respectively. The annular groove is for the stable placement of the sealing ring and to make the sealing ring more compressible; 302 represents a spiral groove formed on the upper surface of the lid top plate; 301 represents a connecting hole that passes through the top plate 300 of the lid; 307 indicates that the connecting hole begins in the area of ​​the lower surface of the top plate 300 surrounded by the sealing ring and leads to the spiral groove 302; the dashed box 309 represents a layer of material in the top plate, referred to here as the reservoir layer 303, which will be further described below; and 304 represents a removable cover plate that covers the spiral groove 302, making it a spiral tunnel. Figure 5A The number 3100 in the text represents Figure 5 A top view of the reservoir layer 309 in the image, wherein 312 represents... Figure 5 In the top view of the spiral groove 302, 314 and 313 represent the materials constituting the reservoir layer 309, wherein 313 forms the spiral groove 302, 314 represents the material surrounding the entire spiral groove 302 from the periphery, and the letter L represented by 315 represents the size of the blank area at the center of the spiral groove 302. Figure 5BThe numerical symbol 3200 in this embodiment represents the bottom view of the lid, where 320 represents... Figure 5 The bottom view of the sidewall 310 in the figure, 321 represents Figure 5 The bottom view of the connection hole 301 in the figure, 326 represents Figure 5 The bottom view of the sealing ring 306 in the figure shows that 327 and 328 represent the portions of the lower surface of the cover plate on the outer and inner sides of the sealing ring, respectively. The portion 328 on the inner side of the sealing ring is referred to here as the sealing ring region of the lower surface of the cover plate. The dashed arrow from B1 to B1 indicates... Figure 5 The cross-sectional position of the lid cross-section diagram described in the figure.

[0016] It should be noted that, Figure 5 and Figure 5A The reservoir layer 309 can be designed in terms of material type and geometry. In some embodiments of the invention, constructing a reservoir using a single reservoir layer is a preferred approach. Combined with... Figures 6 to 7A The following describes the material and structural design of the reservoir layer 309. Additionally, Figure 5 The purpose of the removable cover plate 304 included in the middle cover 3000 will be explained below by combining Figure 8 and 8A The illustration uses a capped inverted chip package for reference.

[0017] Figure 6 and 6A These are schematic diagrams illustrating one embodiment of the present invention. Figure 5 and 5A The reservoir layer 309 in the middle has some design features in terms of material type and geometry. Figure 6 The numerical symbol 3400 indicates a reservoir layer 350, where the arrow line and letter L represented by 345 indicate that the spiral groove 312 contains a large central blank area, 341 and 342 represent the two ports of the spiral groove 312, and 343 explains... Figure 5 The connecting holes 301 or 321 in 5A are respectively positioned at the diagonal position of the inner port 341 of the spiral groove 312. Figure 6A The number 3500 in the diagram is shown. Figure 6 The image shows a cross-sectional view of the reservoir layer 350, wherein a layer of material different from the cap top sheet can be used to fabricate the reservoir layer 350. It should be noted that the reservoir layer can be fabricated by printing a layer of material containing spiral grooves onto the upper surface of the cap top sheet. Figure 7 and Figure 7A These are schematic diagrams illustrating another embodiment of the invention. Figure 5 and5A The reservoir layer 309 in the middle has some design features in terms of material type and geometry. Figure 7 The numerical symbol 3600 in the diagram represents a cross-sectional view of a lid, where 360 ​​and 361 represent a spiral groove constructed in the upper surface 363 of the lid's top plate and a spiral protrusion disposed therein, respectively, and 362 represents a connecting hole in the lid. It should be noted that... Figure 6A The number 3500 in the diagram is shown. Figure 6 The image shows a cross-sectional view of the reservoir layer 350, in which a layer of material different from the top cover plate is used to fabricate the reservoir layer 350. It should be noted that a spiral protrusion material 361 can form a reservoir layer that, when used in conjunction with a cover plate, can be used to store liquid materials. Figure 7A 3700 in Figure 7 The top view of the cover described herein, wherein 371 and 372 represent the top views of the spiral protrusion 361 and the connecting hole 362.

[0018] It should be noted that using a different material to construct a reservoir layer on the upper surface of the cap can bring many advantages. For example, rubber-type materials can be used, and various patterns of reservoir layers can be flexibly created on the upper surface of the cap using printing methods.

[0019] Figure 8 This is a schematic diagram illustrating an embodiment of the present invention based on... Figure 5 The shown is a capped inverted chip package. Figure 8 The numerical symbol 4000 represents a reverse chip package with a cap containing a liquid thermal interface material layer, where 400 and 160 represent a cap and a reverse chip package. The reverse chip package 160 consists of a reverse chip 410 and a circuit board 420. The cap 400 is bonded to the peripheral area of ​​the upper surface of the circuit board and covers the chip 410. A sealing ring 406 seals the gap between the chip 410 and the cap 400 from the edge area of ​​the gap and forms a sealed gap 430. The cap 400 includes a spiral groove 302. A removable cover plate 404 covers the spiral groove 302 to form a spiral tunnel. A liquid material fills the sealed gap 430 and partially fills the spiral tunnel as shown in 402. The liquid material in the sealed gap 430 forms a liquid thermally conductive interface material layer connecting the upper surface of the chip 410 and the lower surface of the cover 400. Simultaneously, the liquid material 402 in the spiral tunnel can also serve as a liquid thermally conductive interface material layer connected to a heat sink, such as... Figure 8A As shown.

[0020] It should be noted that, Figure 8 The purpose of the capped or covered inverted chip package including a removable cover plate 404 is to temporarily protect the liquid material 402 in the spiral tunnel, so that the capped inverted chip package 4000 can be transported and tested without concern about leakage of the liquid material. Figure 8A As shown, in the practical application of the capped inverted chip package 4000, the removable cover 404 can be replaced with the desired heat sink, so that the liquid material 402 in the spiral tunnel becomes the thermal interface material layer between the capped inverted chip package 450 and the heat sink 440. It is evident that the advantage of a cover containing a reservoir on top is that the liquid material connected via a connection hole can simultaneously serve as thermal interface material layer 1 and thermal interface material layer 2 (TIM1 and TIM2).

[0021] Figures 9 to 10 These are schematic diagrams illustrating a preferred embodiment of the invention, showing a reservoir constructed on the lower surface of a cap containing a reservoir structure and its corresponding capped inverted chip package. Figure 9 , Figure 9A , Figure 9B and Figure 9C These are schematic diagrams illustrating cross-sectional and bottom views of a lid containing a reservoir structure built on the lower surface of a lid in a preferred embodiment of the invention. Figure 9 The numerical symbol 5000 in the figure represents a cross-sectional view of the lid, where 500 and 510 represent the top plate and sidewall of the lid, respectively; 505 and 506 represent an annular groove on the lower surface of the top plate and a sealing ring installed therein, respectively; 502 represents a spiral groove formed on the lower surface of the top plate surrounding the annular groove; and 501 represents a connecting hole in the top plate of the lid that bypasses the sealing ring, which begins in an area on the lower surface of the lid surrounded by the sealing ring and connects to the spiral groove 502 as shown in 512. Figure 9A The numerical symbol 5100 in the figure represents a bottom view of the lid, where 512 represents... Figure 9 A bottom view of the spiral groove 502, where 512A and 512B represent the inner and outer ports of the spiral groove 502, respectively, and 511 represents... Figure 9 Bottom view of the central connecting hole 501, and 516 represents... Figure 9 Bottom view of the central sealing ring 506. Figure 9B The number 5500 in the text represents Figure 9The cover 5000 or 5100 described in 9B further includes a cover plate 551, where 550 and 560 represent the cross-sectional view and bottom view of the cover, respectively. The cover plate 551 is adhered to the lower surface of the cover and covers the spiral groove 502 to form a spiral tunnel 522, and the dashed arrow from C1 to C1 in 560 represents the cross-sectional position of the cover's cross-sectional view 550. It should be noted that the outer port 512A of the spiral tunnel 522 should not be covered so that the tunnel 522 opens to the atmosphere; alternatively, this outer port may also be... Figure 3 It is positioned on the side of the lid as shown in the illustration. Figure 9C The number 5800 in the text represents Figure 9B The cover 5500 further includes a gas heat exchange chamber 580 on its top, the top plate of which forms the substrate of the gas heat exchange chamber 580, thereby forming a gas heat exchange chamber containing a liquid storage structure in its substrate. 581, 582, and 583 represent the chamber, outer shell layer, and capillary layer attached to the outer shell layer 582 within the chamber 581, respectively. In another embodiment of the invention later, [the following will be combined with...] Figures 31 to 33 A further detailed explanation of the gas heat exchanger chamber.

[0022] Figure 10 This is a schematic diagram used to illustrate the use of Figure 9The described cover 5500 is a capped inverted chip package, wherein the numerical symbol 6000 represents a cross-sectional view of the package, which consists of an inverted chip package 160, a cover 600, and a liquid reservoir system. The inverted chip package 160 consists of an inverted chip 610 and a circuit board 620. The cover 600 includes a sealing ring 606 at its bottom, which seals the gap between the inverted chip 610 and the cover 600 and forms a hermetically sealed gap 630. The cover 600 includes a spiral tunnel 522 constructed at its bottom surrounding the sealing ring 606. A liquid material fills the hermetically sealed gap 630 and the connection hole 601 and partially fills the spiral tunnel 522. 631 represents the liquid material filled in the hermetically sealed gap 630, which forms a liquid thermally conductive interface material layer between the chip 610 and the cover 600. 652 represents the liquid filled in the spiral tunnel 522. It should be noted that when the volume of the sealed gap 630 increases, the liquid 652 in the spiral tunnel 522 can flow into the sealed gap 630 through the connecting hole 601 under atmospheric pressure, thereby ensuring that it is always filled with liquid. When the volume of the sealed gap 630 decreases, the hollow part of the spiral tunnel 522 can absorb the excess liquid in the sealed gap 630, thereby ensuring that the pressure of the liquid in the sealed gap 630 does not increase.

[0023] Figure 11 This is a schematic diagram illustrating a liquid reservoir lid with a spiral tunnel structure in the middle layer region of the lid top plate and a corresponding manufacturing method thereof, in one embodiment of the present invention. Figure 11 The cap, represented by 630, includes a top plate 631, a sidewall 632, a sealing ring 626 installed in an annular groove 625 at the bottom of the top plate, a tunnel-shaped reservoir 640 constructed in the middle layer region inside the top plate, and a connecting hole 621. The dashed line 620 in the cap 630 indicates that the top plate 631 and the spiral tunnel reservoir 640 are made by welding two pieces of material, one of which includes a groove for constructing the tunnel reservoir 640. It should be noted that a tunnel-shaped reservoir at the top or bottom of the cap can be created by first making a desired spiral or other type of groove at the top or bottom of the cap and then gluing a cap plate to it. Figure 11 Section 650 illustrates some optional designs for the cover 630 as needed, where dashed line 651 indicates that the top piece of the cover is formed by welding two pieces of metal, wherein the upper piece is an annular cover piece, and the lower piece includes a spiral groove 640 covered by the annular cover piece and a stepped groove 652 outside the sealing ring at its bottom in the peripheral area of ​​its top.

[0024] Figure 12 This is a schematic diagram illustrating a lid in one embodiment of the present invention, wherein the reservoir may be a container in the form of a tube disposed outside the lid. Figure 12 The cap represented by the numeral 6200 includes a top plate 661, a sidewall 662, a sealing ring 626 disposed in an annular groove 625 at the bottom of the cap, a liquid reservoir 660 in the form of a tube, and a connection hole 601 connecting the liquid reservoir in the form of a tube to the inner side of the sealing ring at the bottom of the cap. It should be noted that various forms of containers can be designed on the outside of the cap as liquid reservoirs in the liquid storage structure included in the cap.

[0025] It should be emphasized that, in accordance with the spirit and scope of this invention, various modifications can be made to the geometry of the lid, particularly the liquid reservoir it contains, in the embodiments of this invention to meet various specific needs. For example, Figures 9 to 11 The lid contains a reservoir that is a spiral-shaped tunnel. However, the geometry of the reservoir tunnel is not limited to a spiral shape; it can be set according to specific circumstances. For example, if the aspect ratio of the inverted chip is very large, there may not be enough space to create a spiral-shaped tunnel in the area surrounding the sealing ring at the bottom of the lid. However, a spiral-shaped tunnel with a folded structure can be created around the sealing ring, such as... Figure 13A As shown in Figure 6600, where 660 illustrates a spiral-shaped tunnel with a folded structure surrounding a sealing ring, 663 illustrates the sealing ring, 662 illustrates a connecting hole that bypasses the sealing ring 663 and connects the tunnel 660 to the inner side of the sealing ring 663, and 661 illustrates the sidewall area of ​​the cap. For example, the reservoir in the cap is not limited to just a tunnel, and the cap is not limited to containing only one connecting hole, as... Figure 13 The illustration shows a liquid reservoir within a cap containing two tunnels. Furthermore, the capped inverted chip package is not limited to containing only one chip; modules containing multiple chips or inverted chip packages containing multiple chips can also utilize the cap of this invention, which includes a liquid reservoir structure, thereby forming a liquid thermally conductive interface material layer. This will be discussed below in conjunction with... Figure 14 and Figure 15 A brief description is provided below. Additionally, a case where a reverse-chip package dissipates heat directly through a heatsink containing a liquid reservoir will be discussed in conjunction with the following. Figure 16 Please provide an explanation.

[0026] Figure 13 It is a schematic diagram illustrating that the liquid storage structure in the cap includes two tunnels and its corresponding liquid storage system in the capped inverted chip package. Figure 13The diagram represents a liquid storage system, where 700 represents a sealed slit containing liquid, 701 and 702 represent two folded tunnels constituting the liquid reservoir, 701A and 702A represent two connecting holes connecting the tunnels to the sealed slit, and the rectangular dashed box indicates the area of ​​the cap top plate. It should be noted that one advantage of a liquid storage system containing a reservoir in the form of two tunnels is that liquid can be injected into the system from the port of one of the tunnels without the need for a vacuum. In summary, the liquid reservoir in the cap of the present invention can be designed as a cavity in the cap or preferably as one or more tunnels, which can be formed by grooves in the top, bottom, or middle of the cap. Additionally, the cap top plate can include a reservoir layer that forms the liquid reservoir, which can be made of a different material than the cap top plate and produced by printing.

[0027] Figure 14 This is a schematic diagram illustrating that for a multi-chip module in a reverse chip package, the multi-chip module can be viewed as a chip similarly employing the cap structure of the present invention. Figure 14 In this context, 7100 represents a reverse-chip package of a multi-chip module, which includes chips 711, 712, and 713, a dielectric substrate 710 for assembling these chips, and a molding compound 714. For such a multi-chip module, it can be simply viewed as a reverse-chip package, similarly employing the cap with a liquid storage structure described in the previous embodiments of the invention to obtain a liquid thermal interface material layer. It should be noted that for such a multi-chip module, since the edge of the module is the molding compound 714, the width of the sealing ring at the bottom of the cap can be designed more flexibly.

[0028] Figure 15 , Figure 15A and Figure 15B These are schematic diagrams illustrating a reverse chip package comprising multiple chips in one embodiment of the present invention. Figure 15 In this context, 8000 represents an inverted chip package containing multiple chips, where 801 and 802 represent the multiple chips. Figure 15A In the design, 8100 represents a cover designed according to the inverted chip package 8000 containing multiple chips 801 and 802, where 800 and 810 represent the top plate and sidewall of the cover, respectively; 821 and 822 represent multiple sealing rings mounted on the bottom of the top plate of the cover; 830 represents a spiral groove on the top of the cover; and 811 and 812 represent connection holes corresponding to the sealing rings 821 and 822. Figure 15B8500 in the text represents a multi-chip inverted chip package containing the cap 8100. In this capped multi-chip inverted chip package, a removable cover 850 is attached to the top of the cap, thereby turning the spiral groove 830 in 8100 into a spiral tunnel-shaped reservoir. Then, by filling all the sealed gaps and partially filling the spiral tunnel-shaped reservoir with the required liquid material, a liquid thermal interface material layer is formed in each sealed gap.

[0029] Figure 16 This is a schematic diagram illustrating a case in which a heat sink containing a liquid storage structure directly dissipates heat from the inverted chip package via a liquid thermal interface material layer in one embodiment of the present invention. Figure 16 In this context, 9000 represents a heat sink containing a liquid reservoir structure that directly dissipates heat to the inverted chip package via a liquid thermal interface material layer. 900 and 160 represent a heat sink containing a liquid reservoir structure and an inverted chip package, respectively. The liquid reservoir system, consisting of a reservoir, connecting holes, a sealing gap, and the contained liquid, provides a liquid thermal interface material layer between the chip 161 and the lower surface 911 of the substrate 910 of the heat sink 900. It should be noted that the heat sink can include necessary heat dissipation elements on its upper surface 912 of the substrate. For a detailed description of the liquid reservoir structure and system in the heat sink 900, please refer to the previous section... Figure 3 The description of the liquid storage structure and liquid storage system described above will not be repeated here.

[0030] Combined with the above Figures 13 to 16 Some embodiments of the liquid reservoir structure of the present invention have been described, wherein the liquid reservoir structure consists of a sealing ring, a connecting hole, and a tunnel-shaped liquid reservoir. The cap for a capped inverted chip package is suitable for a tunnel-shaped liquid reservoir. The following will be combined with... Figures 17 to 33 A liquid storage structure consisting of a sealing ring, connecting hole, liquid storage tube and venting tube is described. It is suitable for combination with heat sinks, gas heat exchange chambers, thermally conductive cold plates and other heat sinks to form a heat sink that can use a liquid thermally conductive interface material layer, thereby more effectively dissipating heat for electronic devices.

[0031] Figure 17 This is a schematic diagram illustrating some basic features of a heat sink containing a liquid reservoir structure, which includes: a sealing ring, a connecting hole, a liquid reservoir pipe, and an exhaust pipe. Figure 17In this context, the mathematical symbol C1000 represents a substrate of a heat conductor and its contained liquid storage structure, where C100 indicates a substrate C101 of the heat conductor with the liquid storage structure assembled thereon. The liquid storage structure consists of a sealing ring C106 mounted in an annular groove C105 at the bottom of the substrate, a connecting hole C102, a liquid storage tube C102a, a connecting hole C103, and an exhaust pipe C103a. C101a and C101b represent the upper and lower surfaces of the substrate C101, respectively. Based on the components disposed on the upper surface, the heat sink can be a heat sink fin, a thermally conductive cold plate, or a gas heat exchange chamber. A common feature of these heat sinks is that they are all constructed on a substrate, which will be further explained below. Figure 17 The heat conductor represented by C1000 includes a liquid storage structure characterized by comprising a sealing ring C106 installed in an annular groove C105 at the bottom of the substrate, a liquid storage tube C102a, one or more venting tubes C103a, a connection hole C102 connected to the liquid storage tube C102a leading to a lower surface region of the substrate C101 surrounded by the sealing ring, and one or more connection holes C103 connected to the venting tubes C103a leading to a lower surface region of the substrate C101 surrounded by the sealing ring. Each connection hole C102 or C103 has two ports, the port located on the lower surface region of the substrate surrounded by the sealing ring is called the inner port, and the other port is called the outer port. Each tube, including the liquid storage tube and the venting tube, also has two ports, one of which is connected to the outer port of the connection hole C102 or C103, which is called the inner port of that tube, and the other port is called the outer port. Figure 17 The configuration of the connecting holes C102 and C103 extends from the lower surface of the substrate C101 to the upper surface of the substrate. Some other configurations as needed will be described later. Figure 17 C110 in the diagram is used to describe some other features related to the reservoir C102a, where C111 and C112 represent the liquid material stored in the reservoir C102a and the cap that closes the external port of the reservoir C102a, respectively. It should be noted that, as an example of a geometric configuration, Figure 17 The liquid storage tube C102a shown in the diagram is folded, but it can also be designed into other configurations depending on the available space in the specific situation.

[0032] Figures 18 to 21 These are some diagrams used to illustrate... Figure 17The steps shown involve assembling the heat sink C110, which includes a liquid storage structure, with an electronic device and providing a liquid thermal interface material layer. Further features of the heat sink C110 are also described in the assembly process. The assembly process mainly includes four steps (a) to (d), as described below: (a): Figure 18 C2000 in the text indicates that... Figure 17 The heat sink, as illustrated in C110, is placed on the top C201 of an electronic device C200. The sealing ring C106 is aligned with and tightly pressed against the edge region C201a of the top of the electronic device C200. Thus, as illustrated in C106a, the pressed sealing ring C106 tightly seals the gap between the lower surface C01c of the heat sink substrate C101 and the upper surface C201 of the electronic device C200 from its edge, forming a sealed gap C202. (b): Figure 19 C2100 in the text indicates that by removing the cap C112 of the storage tube C102a, the outer port of the storage tube C102a is opened and a pressure, such as a gas pressure, as indicated by arrow C210, is applied to push the liquid C111 stored in the storage tube C102a to flow into the sealed gap C202 and the gas guide tube C103a, as indicated by the dashed arrow C111a. (c): Figure 20 C2200 in the text indicates that the liquid C111 stored in the liquid storage tube C102a has flowed into the sealed gap C202 and the exhaust pipe C103a, and a liquid thermally conductive interface material layer C222 is formed between the area surrounded by the sealing ring on the lower surface C101c of the substrate C101 and the upper surface C201 of the electronic device. (d): Figure 21 C2300 indicates that after liquid has flowed into the exhaust pipe, the outer port of the exhaust pipe should be closed with a rubber cap or screw cap C230 or other method as shown in C231.

[0033] It should be noted that the above is combined with Figures 18 to 21 The method described for assembling a heat sink and electronic devices together employs, for example... Figure 17 The heat sink represented by C110 includes a liquid reservoir C102a pre-stored with the required liquid material C111. Another assembly method can directly use the heat sink C100, characterized in that the heat sink C100 is first mounted on the electronic device C200, and then the required liquid material is injected from the external port of the liquid reservoir C102a, thereby providing a liquid thermal interface material layer.

[0034] Based on the above Figures 18 to 21 For adoption Figure 17 The description of the heat sink C1000 used to dissipate heat from an electronic device shows that the heat sink C1000 includes the following additional features: a) The substrate C101 includes an annular groove C105 on its lower surface, and a sealing ring C106 is installed in the annular groove C105. Together with the portion of the lower surface of the substrate surrounded by the sealing ring C106, the sealing ring C106 directly covers the upper surface of the electronic device C200 from the edge region of the upper surface C201 of the electronic device C200, thereby forming a sealed gap C202 between the lower surface C101c of the substrate C101 and the upper surface 201 of the electronic device C200. The sealed gap C202 is filled with a set liquid material, thereby providing a liquid thermally conductive interface material layer C222. b) After the liquid thermal interface material layer C222 is formed, the outer port of the liquid storage pipe C102a remains open to the atmospheric environment, while the outer end of the exhaust pipe C103a is closed. It should be noted that the method of closing the outer port of the exhaust pipe C103a can be flexibly designed. Besides using a rubber cap or screw cap represented by C230, the arrow line indicates another preferred method C231, characterized in that the exhaust pipe C103a includes a float structure C231 at its outer port. C231a represents a float, and C231b represents a small hole C231b at the outer port of the exhaust pipe C103a, smaller than the size of the float C231a. Thus, when liquid C223 is filled into the exhaust pipe C103a, the float C231a will block the small hole C231b, i.e., close the outer port of the exhaust pipe C103a.

[0035] Figure 22 and Figure 23 These are schematic diagrams illustrating the problems stated in this invention and the physical principles employed to solve them. It is recognized that due to the difference in thermal expansion coefficients between the silicon chip and the circuit board made of organic materials, the upper surface of the electronic device C200, which includes both the chip and the circuit board made of organic materials, cannot always remain horizontal, but rather... Figure 22 C301 / C301a or Figure 23As shown in C311 / C311a, warping upwards or downwards with temperature changes is referred to as warping in electronic devices such as inverted chip packages. When a heat sink is assembled and fixed to the upper surface of the electronic device C200, the volume of the gap between them changes with temperature due to this warping. This volume change can be very large; in some unfavorable situations, the volume at high temperatures can be twice or more than the volume at low temperatures. Therefore, when using a liquid thermal interface material layer, simply sealing the gap between the heat sink and the electronic device with a sealing ring to prevent liquid leakage is insufficient. For example, when the gap volume decreases, the liquid within is compressed, creating high pressure, which can damage the sealing ring over time. Conversely, when the gap volume increases, the liquid is insufficient to fill the enlarged gap, resulting in voids that prevent the heat sink from effectively dissipating heat from the electronic device. This invention solves this problem. Its basic principle is to use a liquid reservoir connected to a sealed gap via a connecting hole, such as the tunnel in the cap described above. Figures 17 to 23 The liquid storage tube shown is provided, and the liquid storage device must have an external port that leads to the atmospheric environment, so that the flow of liquid in the liquid storage device can be driven by the pressure of the ambient atmosphere. Figure 22 In the diagram, C301 and C301a indicate that the electronic device C200 is warped upwards, resulting in a smaller volume of the sealed gap. The dashed arrows indicating C302 and C303 show that excess liquid in the sealed gap flows into the storage tube C102a, thus preventing an increase in the liquid pressure within the sealed gap. Figure 23 In the diagram, C311 and C311a indicate that the downward warping of electronic device C200 causes an increase in the volume of the sealed gap. The dashed arrows in C312 and C313 represent the liquid stored in the sealed gap flowing into it under atmospheric pressure, replenishing the gap and ensuring it remains fully filled. It should be noted that this is because the external port of the liquid storage tube is open to the atmosphere. Figure 22 The diagrams C302 and C303 illustrate the flow of liquid from the sealed gap into the storage tube C102a. Figure 23 The flow of liquid from the storage tube C102a to the sealed gap, as illustrated in C312 and C313, is thus achieved.

[0036] Based on the above Figure 22 and Figure 23The explanation shows that when the sealed gap is filled with liquid, the outer port of the vent pipe needs to be closed. Otherwise, the liquid reservoir, vent pipe, and atmospheric environment will form a loop, and the liquid may leak out under gravity. Closing the outer port of the vent pipe leaves only one opening to the atmosphere in the entire liquid system—the outer port of the reservoir. Therefore, even if the outer port of the reservoir is facing downwards, gravity will not cause liquid to flow out. It should be noted that when removing the heat sink from the electronic device, the outer port of the vent pipe can be opened first. This allows the liquid in the sealed gap to be drawn back into the reservoir, and then the heat sink can be safely removed from the electronic device without worrying about leakage from the sealed gap.

[0037] Figure 24 and Figure 25 These are schematic diagrams illustrating some designs of the geometric configuration of the annular groove at the bottom of the heat conductor substrate for mounting the sealing ring in some embodiments of the present invention, as well as some schemes for the configuration of the connection hole connecting the liquid storage pipe and the exhaust pipe and the positioning of its inner port at the bottom of the heat conductor substrate. Figure 24 C4200 represents Figures 17 to 23The diagram illustrates a cross-sectional view C120 and a bottom view C130 of the substrate C101, which is a heat conductor. The dashed arrow C131 in the bottom view C130 indicates the location of the cross-section in the cross-sectional view C120. In the cross-sectional view C120 of the substrate C101, C102c and C102b represent the inner and outer ports of the connecting hole C102, and C103c and C103b represent the inner and outer ports of the connecting hole C103. The connection method between the outer port of the connecting hole and an external tube can be designed as a bolted connection or adhesive bonding, etc. These are conventional designs in industrial production and will not be detailed here. In the bottom view C130 of the substrate C101 in this embodiment, the position design of the inner ports of the connecting holes C102 and C103 will be explained in detail. The part of the lower surface of the substrate surrounded by the sealing ring C125 is a rectangular area C141, and C142 and C142a represent its four corner areas. The heat sink of this embodiment includes three exhaust pipes. The inner ports C133, C134 and C135 of the three connecting holes connecting these three exhaust pipes are respectively set in the three corner areas represented by C142. The inner port C132 of the connecting hole connecting the liquid storage pipe is set in the remaining corner area. Thus, when the liquid in the liquid storage pipe flows out through the inner port C132 of the connecting hole, it can flow as indicated by the dashed arrows C143, C144 and C145 and easily fill the entire sealed gap without easily generating air bubbles. It should be noted that the heat sink in the embodiments of the present invention can also be a single exhaust pipe. For the design of a single exhaust pipe, the two inner ports of the two connecting holes connecting the liquid storage pipe and the heat sink should be respectively set with the two diagonal regions of the rectangular area C141 surrounded by the sealing ring C125, such as C132 and C134.

[0038] Figure 25C4500 illustrates some optional designs for the geometry of the connection holes in the substrate of the heat conductor and the annular groove at the bottom of the substrate in some embodiments of the present invention, where C150 and C160 represent cross-sectional and bottom views of the substrate, respectively. In the cross-sectional view of the substrate represented by C150, 152 and 153 indicate that the connection holes can be designed in the substrate as needed, so that the outer ports 152b and 153b of the connection holes do not need to be aligned with their inner ports 152c and 153c from bottom to top, but can be set at the desired position on the substrate. C155 in the cross-sectional view of the substrate represented by C150 indicates that the annular groove can be hemispherical or other grooves with a slightly larger bottom, so that the sealing ring can be locked in it and is not easily dislodged. In the bottom view of the substrate represented by C160, C162, C163, C164, and C165 represent the four inner ports of the corresponding four connection holes in the heat conductor with four exhaust pipes. They are located at the four corners of the rectangular area at the bottom of the substrate surrounded by the sealing ring C125. The inner port C165 of the connection hole corresponding to the liquid storage tube in the heat conductor is located in the middle area of ​​the rectangular area at the bottom of the substrate surrounded by the sealing ring C125. This arrangement of the inner ports of the connection holes allows the liquid in the liquid storage tube to flow out through the inner port C161 of the connection hole and then flow as indicated by the dashed arrows C172, C173, C174, easily filling the entire sealed gap without generating air bubbles.

[0039] Figures 26 to 32 These are schematic diagrams illustrating cases where the heat sink C110 in some of the foregoing embodiments of the invention is a heat sink, a cold plate, or a gas heat exchange chamber.

[0040] Figure 26 To illustrate an example where the heat sink in the foregoing embodiments of the present invention is a heat sink, the mathematical symbol C5000 represents the heat sink C500, which is mounted as a heat sink on a reverse-chip package C510. The reverse-chip C200 in the reverse-chip package C510 is bonded to the circuit board C512 via solder balls C514 and filler material C513, while the heat sink C500 is... Figure 21 The heat sink described in C2300 is formed by adding heat dissipation fins C502 to the substrate C101. Other features of the heat sink C500 can be found in [reference needed]. Figure 21 The description of C2300 in the document. Figure 27 The illustration shows some alternative designs for the annular groove and sealing ring included in the heat sink of the present invention, wherein the annular groove C505 and the sealing ring C506 in C5200 are characterized in that the sealing ring C506 is pressed against the circuit board and seals the entire side of the inverting chip. Figure 28In the diagram, C6000 represents a heat sink C500 with a liquid storage structure mounted on a capped inverted chip package C600. For simplicity, the cap C601 of the package C600 is only shown here. The heat sink is characterized by a sealing ring that seals the peripheral area of ​​the top of the cap. C602 and C603 indicate that the cap may also include an annular groove, so that the sealing ring can be clamped between the two annular grooves.

[0041] Figure 29 and Figure 30 This is an example illustrating that the heat sink in the foregoing embodiments of the present invention is a cold plate. Figure 29 The C7000 in the diagram describes a conventional cold plate C700 that dissipates heat from an electronic device C200 through a conventional thermally conductive interface material layer C710. The cold plate primarily consists of a substrate C701, a cap-shaped cover C702, and a heat dissipation system comprising C703, C704, C705, and C706. C703 represents the compartment formed by the substrate C701 and the cover C702. C706 and C704 represent fluid inlet and outlet pipes, respectively. The dashed arrow C705 indicates a circulation system that drives a coolant to flow into and out of the compartment C703, thereby removing heat from the electronic device C200. For simplicity, the circulation system C705 is not described in detail here. Figure 30 The C7200 in the above-described embodiment is an example of a cold plate C720 containing a liquid storage structure. The substrate C701a includes an outwardly extending portion that allows the liquid storage pipe C102a and the exhaust pipe C103a to be positioned outside the compartment C703. Connection holes C722 and C723 in the substrate C701a extend laterally through the substrate for a distance so that their outer ports are located on the surface of the portion of the substrate C701a extending outward from the compartment C703. The cold plate C720, based on its included liquid storage structure, forms a liquid thermally conductive interface material layer C222 in the gap between itself and the electronic device. It should be noted that the same numerical symbols in different figures represent the same components, and for simplicity, they will not be repeated.

[0042] Figure 31 , Figure 32 and Figure 33 This is an example illustrating that the heat sink in the foregoing embodiments of the present invention is a gas heat exchange chamber containing a liquid storage structure.

[0043] Figure 31The term C8000 describes a conventional gas heat exchanger chamber comprising an outer shell layer C801 forming a chamber C800, a capillary layer C802 attached to the outer shell layer C801 within the chamber C800, and a two-phase material contained within the chamber C800, namely a liquid phase C802a and a gas phase C804. The outer shell layer C801 of the chamber C800 mainly consists of a substrate C801a and a top plate C801b. In gas heat exchanger applications, the substrate C801a contacts a heat source to dissipate heat, while the top plate C801b contacts a cold source to remove heat. It should be noted that the arrows C802a and C804 also indicate the flow of this two-phase material within the chamber C800 and the interconversion between the gas and liquid phases. Arrow C803 indicates a heat source, such as the heat input of an electronic device, originating from the substrate C801a of the gas heat exchange chamber. This heat heats the liquid material C802a in the capillary layer C802 at the substrate C801a and vaporizes it into a gaseous material C804. When this gaseous material C804 reaches the capillary layer C802 at the top plate C801b, it is cooled back into a liquid phase by the cold source indicated by arrow C803a. Then, as indicated by arrow C802a, it flows back to the substrate C801a under the action of capillary force in the capillary layer C802. This cycle is the process by which the gas heat exchange chamber dissipates heat for an electronic device.

[0044] Figure 32 In this context, C8100 indicates that the heat sink in the foregoing embodiments of the present invention is an example of a gas heat exchange chamber, which is made by adding a liquid storage structure to a conventional gas heat exchange chamber. C815 represents an annular groove formed on the lower surface of the bottom plate of the gas heat exchange chamber, C816 represents a sealing ring installed in the annular groove, C813 and C814 represent connecting holes that extend from the bottom plate to the top plate of the gas heat exchange chamber, C813a and C814a represent a liquid storage pipe and one or more exhaust pipes respectively connected to the connecting holes C813 and C814, and C814b represents a cap that closes the outer port of the exhaust pipe. Figure 33 In the diagram, C8200 represents a bottom view of the gas heat exchange chamber, where the dashed arrow C820 indicates... Figure 32 The cross-sectional position of the cross-sectional view of the gas heat exchanger chamber described herein, where C823 represents... Figure 32 Bottom view of the center connection hole C813, and C824, C834, and C844 represent... Figure 32 Bottom view of the central connection hole C814. It should be noted that, as an example, this bottom view C8200 of the gas heat exchanger only shows the liquid storage structure of the gas heat exchanger including three exhaust pipes; furthermore, the process of assembling the gas heat exchanger C8100 with an electronic device to form a liquid thermally conductive interface material layer is combined with the previous... Figures 26 to 30 The description of the heat sink of the present invention and its role in heat dissipation for an electronic assembly is similar and will not be repeated here for the sake of brevity.

[0045] It should be noted that the spirit and scope of this invention is to add a liquid storage structure to a conventional heat sink to form the heat sink of this invention. The key feature is that the liquid storage structure reliably provides a liquid thermally conductive interface material layer for the gap between the electronic device and the heat sink, thereby improving the thermal conductivity from the electronic device to the heat sink. To achieve this, the liquid storage structure of this invention includes a sealing ring, one or more connecting holes, and a liquid reservoir; the liquid reservoir includes a port leading to the atmospheric environment, which can utilize the pressure of the ambient atmosphere to drive the flow of liquid therein, thereby ensuring that the sealed gap between the electronic device and the heat sink, sealed by the sealing ring, is always filled with the liquid thermally conductive interface material without generating high pressure. As an example of a heat sink, Figures 3 to 15 The main description includes a cap with a liquid storage structure and a capped inverted chip package based on this cap, wherein the liquid reservoir in the liquid storage structure is fabricated in the substrate of the cap. Figure 16 A heat sink is described, in which the liquid reservoir in the liquid storage structure is also fabricated in the substrate of the heat sink. Figures 17 to 33 A heat sink is described, comprising a liquid reservoir in its liquid storage structure, which is a liquid storage tube outside its substrate. The liquid storage structure also includes one or more vent pipes. The purpose of the vent pipes is to allow liquid to fill the sealed gap between the electronic device and the heat sink when the heat sink is assembled with an electronic device in a non-vacuum environment. For an electronic device where a semiconductor chip is its heat-generating element, its heat sink typically includes a lid (also called an integrated heat spreader, IHS), a heat sink, a cold plate, and a vapor chamber, or a combination thereof. A common feature of these heat sinks is that they all include a substrate that contacts and dissipates heat from the electronic device through a thermally conductive interface material layer.

[0046] Although the invention has been described in detail with reference to some embodiments for illustrative purposes, it is obvious that many modifications can be made to the described embodiments within the spirit and scope of the invention to meet specific needs.

Claims

1. A heat sink that can use a liquid thermally conductive interface material layer to dissipate heat from an electronic device, comprising: A substrate comprising an upper surface and a lower surface, and a liquid storage structure, wherein the liquid storage structure comprises a sealing ring, a liquid reservoir, and at least one connecting hole, characterized in that: the substrate includes an annular groove on its lower surface, the sealing ring is installed in the annular groove, and the gap between the lower surface of the substrate and the upper surface of the electronic device is sealed from its periphery by the sealing ring, thereby forming a sealed gap; the liquid reservoir is a container formed in the substrate and includes two ports, and the connecting hole is a channel in the substrate and includes two ports, one of the ports of the connecting hole being located on the substrate. In the area surrounded by the sealing ring on the lower surface, another port of the connecting hole is connected to one port of the reservoir, while the other port of the reservoir is open to the atmosphere. The liquid material fills the sealed gap and partially fills the reservoir, so that when the volume of the sealed gap decreases, the excess liquid can flow into the empty space of the reservoir through the connecting hole, and when the volume of the sealed gap increases, the liquid in the reservoir can flow into the sealed gap through the connecting hole under the pressure of the ambient atmosphere, thereby ensuring that the sealed gap is always filled with liquid thermally conductive interface material without generating high pressure.

2. The heat sink as described in claim 1, characterized in that, The reservoir is a tunnel in the substrate surrounding the outside of the sealing ring, and one port of the reservoir leads to the sealed gap via the connection hole.

3. The heat sink as described in claim 1, characterized in that, The substrate includes a groove on its upper surface, and the heat sink further includes a removable cover that covers the groove, thereby forming a reservoir included in the liquid storage structure.

4. The heat sink as described in claim 1, characterized in that, The substrate includes a groove surrounding the outside of the sealing ring on its lower surface, and the heat sink further includes a cover plate that covers the groove, thereby forming the reservoir.

5. The heat sink as described in claim 1, characterized in that, The heat sink further includes a liquid material in the reservoir for forming a liquid thermal interface material layer in the sealed gap.

6. The heat sink as described in claim 1, characterized in that, The heat sink further includes a thin film material attached to the lower surface of the substrate within the area surrounded by the sealing ring on the lower surface of the substrate. This film material becomes liquid at high temperatures and forms a liquid thermally conductive interface material layer in the sealed gap.

7. The heat sink as described in claim 1, characterized in that, The heat sink is a cap used in a capped inverted chip package, the cap comprising a top plate and a sidewall, wherein the top plate constitutes the substrate, which contains the liquid reservoir structure.

8. The heat sink as described in claim 2, characterized in that, The tunnel is a spiral tunnel or a spiral tunnel containing folded structures.

9. The heat sink as described in claim 7, characterized in that, The top of the cover is a gas heat exchange chamber, and its substrate contains the liquid storage structure.

10. A heat sink for dissipating heat from an electronic device using a liquid thermally conductive interface material layer, comprising: A substrate comprising an upper surface and a lower surface, and a liquid storage structure, wherein the liquid storage structure comprises a sealing ring, a liquid storage tube, one or more vent pipes, and one or more connecting holes, characterized in that: the substrate includes an annular groove on its lower surface, the sealing ring is installed in the annular groove, and the gap formed between the lower surface of the substrate and the upper surface of the electronic device is sealed from its periphery by the sealing ring, thereby forming a sealed gap; the liquid storage tube is a tube with two ports located outside the substrate, and each liquid storage tube or each vent pipe has a corresponding connecting hole, each connecting hole being a channel with two ports in the substrate, one port of the connecting hole corresponding to the liquid storage tube being located in the area of ​​the lower surface of the substrate surrounded by the sealing ring, and the other port of the connecting hole being... One port is connected to one port of the liquid storage tube, while the other port of the liquid storage tube is open to the atmosphere. Correspondingly, one port of the connection hole of the exhaust pipe is located in the area surrounded by the sealing ring on the lower surface of the substrate, while the other port of the connection hole is connected to one port of the exhaust pipe. The other port of the exhaust pipe is closed after the sealed gap is filled with liquid material. The liquid material fills the sealed gap and partially fills the liquid storage tube, so that when the volume of the sealed gap decreases, excess liquid can flow into the empty space of the liquid storage tube through the connection hole. When the volume of the sealed gap increases, the liquid in the liquid storage tube can flow into the sealed gap through the connection hole under the pressure of the ambient atmosphere, thereby ensuring that the sealed gap is always filled with liquid thermally conductive interface material without generating high pressure.

11. The heat sink as claimed in claim 10, characterized in that, The electronic device is a reverse chip package consisting of a reverse chip and a circuit board, with the sealing ring encapsulating the peripheral area of ​​the upper surface of the reverse chip.

12. The heat sink as described in claim 10, characterized in that, The electronic device is a capped inversion chip package consisting of an inversion chip, a circuit board, and a cap, wherein the sealing ring seals the peripheral area of ​​the upper surface of the cap.

13. The heat sink as described in claim 12, characterized in that, The upper surface of the cover includes an annular groove, and the sealing ring is clamped between the annular groove located on the lower surface of the substrate and the annular groove located on the upper surface of the cover.

14. The heat sink as described in claim 10, characterized in that, The heat sink further includes a rubber cap or screw cap for closing the outer port of the exhaust pipe.

15. The heat sink as described in claim 10, characterized in that, Each exhaust pipe of the heat sink further includes a float for closing the outer port of the exhaust pipe.

16. The heat sink as claimed in claim 10, characterized in that, The heat sink includes a liquid storage pipe or an exhaust pipe, which is connected to its corresponding connection hole by screws or adhesive.

17. The heat sink as claimed in claim 10, characterized in that, The heat sink includes a liquid storage tube that is a folded tube.

18. The heat sink as claimed in claim 10, characterized in that, The heat sink includes one, three, or four exhaust pipes.

19. The heat sink as claimed in claim 10, characterized in that, The heat sink is a heat sink fin, a cold plate, or a gas heat exchange chamber.

20. An electronic device heat sink assembly comprising a liquid thermally conductive interface material layer, comprising: An electronic device and a heat sink are disclosed, wherein the electronic device includes an upper surface through which heat generated is transferred to the heat sink via a liquid interface thermally conductive material layer. The heat sink includes a substrate comprising an upper surface and a lower surface, and a liquid reservoir structure comprising a sealing ring, a reservoir, and at least one connection hole. The substrate has an annular groove on its lower surface, the sealing ring is installed in the annular groove, and the gap between the lower surface of the substrate and the upper surface of the electronic device is sealed from its periphery by the sealing ring, thereby forming a sealed gap. The reservoir is a container formed in the substrate and includes two ports. The connection hole is... The substrate has a channel with two ports. One port of the connection hole is located on the lower surface of the substrate in the area surrounded by the sealing ring, while the other port of the connection hole is connected to one port of the reservoir, and the other port of the reservoir is open to the atmosphere. The liquid material fills the sealed gap and partially fills the reservoir, so that when the volume of the sealed gap decreases, the excess liquid can flow into the empty space of the reservoir through the connection hole. When the volume of the sealed gap increases, the liquid in the reservoir can flow into the sealed gap through the connection hole under the pressure of the ambient atmosphere, thereby ensuring that the sealed gap is always filled with liquid thermally conductive interface material without generating high pressure.

21. The electronic device heat sink assembly as described in claim 20, characterized in that, The electronic device heat sink assembly is a flip-chip package with a cover, wherein the electronic device is a flip-chip package, and the heat sink is a cover including a top plate and a sidewall, wherein the top plate constitutes the substrate of the heat sink.

22. The electronic device heat sink assembly as claimed in claim 21, characterized in that, The substrate includes a groove on its upper surface, and the cover further includes a removable cover plate that covers the groove, thereby forming a reservoir included in the liquid storage structure.

23. The electronic device heat sink assembly as described in claim 21, characterized in that, The liquid storage structure includes a liquid reservoir that is a tunnel surrounding the outside of the sealing ring in the top plate, and one port of the liquid reservoir leads to the sealed gap via the connecting hole.

24. The electronic device heat sink assembly as described in claim 23, characterized in that, The tunnel is a spiral tunnel or a spiral tunnel containing folded structures.

25. The electronic device heat sink assembly as described in claim 20, characterized in that, The electronic device heat sink assembly is a capped inverted chip package, wherein the electronic device is an inverted chip package and the heat sink is a cap in the form of a gas heat exchange chamber containing a liquid storage structure in the substrate.

26. The electronic device heat sink assembly as claimed in claim 21, characterized in that, The inverted chip package is an inverted chip package that includes a multi-chip module.

27. The electronic device heat sink assembly as claimed in claim 21, characterized in that, The inverted chip package is an inverted chip package containing multiple chips.

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