Stacked heat dissipation packaging structure and preparation method thereof

Abstract

The present invention provides a stacked heat dissipation packaging structure and a preparation method thereof, relating to the field of chip packaging technology. The stacked heat dissipation packaging structure includes a substrate, a first chip, a heat dissipation adhesive layer, a first heat dissipation fin, a second heat dissipation fin, a plastic package, and solder balls. The first chip is mounted on the substrate, and a chip groove is provided on a non-functional surface of the first chip; the heat dissipation adhesive layer is provided in the chip groove; the first heat dissipation fin and the second heat dissipation fin are both provided in the chip groove, and the second heat dissipation fin is bent and extended onto the first heat dissipation fin, with a heat dissipation gap formed between the second heat dissipation fin and the first heat dissipation fin. Compared with the prior art, the present invention arranges both the first heat dissipation fin and the second heat dissipation fin on the heat dissipation adhesive layer, which can greatly increase the heat dissipation area, thereby improving the heat dissipation effect and heat dissipation performance. It can also effectively reduce the stacking height, which helps to achieve miniaturization of the packaging structure.

Description

Technical Field

[0001] The present invention relates to the technical field of chip packaging, and in particular to a stacked heat dissipation packaging structure and a preparation method thereof. Background Art

[0002] With the rapid development of the semiconductor industry, flip-chip stacking hybrid packaging structures are often adopted to meet the multifunctionality and miniaturization requirements of electronic packaging products. As stacking density continues to increase, chip operating temperatures rise sharply, potentially leading to thermal failure and warping of the stacked chips, resulting in temporary failure or permanent damage. Therefore, it is imperative that electronic devices have good heat dissipation performance to avoid exceeding the normal operating temperature range of the chips and causing thermal failure. Summary of the Invention

[0003] The purpose of the present invention is to provide a stacked heat dissipation packaging structure and a method for preparing a stacked heat dissipation packaging structure, which can improve the heat dissipation effect, avoid thermal failure caused by exceeding the normal operating temperature range of the chip, and can effectively reduce the stacking height, thereby helping to achieve miniaturization of the packaging structure.

[0004] In a first aspect, the present invention provides a stacked heat dissipation packaging structure, comprising:

[0005] substrate;

[0006] a first chip mounted on the substrate, wherein a functional surface of the first chip is connected to the substrate, and a chip groove is provided on a non-functional surface of the first chip;

[0007] A heat dissipation adhesive layer is provided in the chip groove, wherein the heat dissipation adhesive layer at least covers the bottom wall of the chip groove;

[0008] A first heat dissipation fin and a second heat dissipation fin are provided in the chip groove, wherein the first heat dissipation fin is attached to the heat dissipation adhesive layer, and the second heat dissipation fin is provided on the heat dissipation adhesive layer and is bent and extended to a side of the first heat dissipation fin away from the substrate, with a heat dissipation gap formed between the second heat dissipation fin and the first heat dissipation fin;

[0009] A plastic package is provided on the substrate, the plastic package covers the first chip and fills the chip groove, so that the first heat dissipation dummy sheet and the second heat dissipation dummy sheet are covered in the plastic package;

[0010] The solder balls are arranged on a side of the substrate facing away from the first chip.

[0011] In an optional embodiment, the second heat dissipation fin includes a base heat dissipation portion and a bent heat dissipation portion distributed in an L-shape, the base heat dissipation portion is attached to the heat dissipation adhesive layer and is spaced apart from the side wall of the first heat dissipation fin, and the bent heat dissipation portion is bent and extended from the base heat dissipation portion toward a side of the first heat dissipation fin away from the substrate, and is spaced apart from the top side surface of the first heat dissipation fin, so that the heat dissipation gap is L-shaped.

[0012] In an optional embodiment, a first heat-conducting connecting line is provided on the first heat-dissipating fin, the first heat-conducting connecting line is spaced apart from the second heat-dissipating fin, and is connected to the heat-dissipating adhesive layer.

[0013] In an optional embodiment, a second heat conducting connection line is provided on a side of the second heat dissipation fin away from the substrate, the second heat conducting connection line is spaced apart from both the first heat dissipation fin and the first heat conducting connection line, and is connected to the heat dissipation adhesive layer.

[0014] In an optional embodiment, the first heat-conducting connecting line is provided on both sides of the first heat-dissipating fin, and the first heat-conducting connecting line close to the second heat-dissipating fin extends to the heat-dissipating gap;

[0015] The second heat-conducting connecting wires are arranged on both sides of the second heat dissipation fin.

[0016] In an optional embodiment, the bonding height of the second thermally conductive connection line relative to the heat dissipation adhesive layer is greater than the depth of the chip groove relative to the heat dissipation adhesive layer, and the bonding height of the first thermally conductive connection line relative to the heat dissipation adhesive layer is less than the depth of the chip groove relative to the heat dissipation adhesive layer.

[0017] In an optional embodiment, the height of the second heat dissipation dummy sheet relative to the heat dissipation adhesive layer is less than the depth of the chip groove relative to the heat dissipation adhesive layer, and the second heat conductive connecting line and the first heat conductive connecting line are both enclosed in the plastic package.

[0018] In an optional embodiment, a filling adhesive layer is further provided between the substrate and the first chip, a functional surface of the first chip is provided with bumps, the bumps are connected to the substrate, and the filling adhesive layer covers the outside of the bumps.

[0019] In an optional embodiment, a third heat-conducting connecting line is further provided in the heat dissipation gap, and the third heat-conducting connecting line is provided in an arch shape on the surface of the first heat dissipation fin and / or the second heat dissipation fin.

[0020] In an optional embodiment, a first metal column is further provided between the first heat dissipation fin and the second heat dissipation fin, wherein the bottom end of the first metal column is connected to the side of the first heat dissipation fin away from the substrate, and the top end of the first metal column is connected to the second heat dissipation fin.

[0021] In an optional embodiment, the stacked heat dissipation packaging structure also includes a second chip, which is spaced apart on the side of the first chip away from the substrate and is coated with the plastic package, and the functional surface of the second chip faces the first chip. A conductive column is provided on the edge of the functional surface of the second chip, and the conductive column extends and is connected to the substrate and is spaced apart from the first chip.

[0022] In an optional embodiment, a second metal column is further provided in the middle of the functional surface of the second chip, and the second metal column extends and connects to a side surface of the second heat dissipation fin facing away from the first metal column.

[0023] In an optional embodiment, the functional surface of the second chip is further provided with an electrostatic pad, the electrostatic pad is electrically connected to the conductive column, and the electrostatic pad is connected to the second metal column.

[0024] In an optional embodiment, there are multiple first metal pillars and multiple second metal pillars, and the multiple first metal pillars and the multiple second metal pillars correspond to each other.

[0025] In a second aspect, the present invention provides a method for preparing a stacked heat dissipation packaging structure, which is used to prepare the stacked heat dissipation packaging structure as described in the above embodiment, and the preparation method includes:

[0026] providing a substrate;

[0027] Mounting a first chip on the substrate, wherein a functional surface of the first chip is connected to the substrate;

[0028] forming a chip groove on a non-functional surface of the first chip;

[0029] forming a heat dissipation adhesive layer in the chip groove, wherein the heat dissipation adhesive layer at least covers the bottom wall of the chip groove;

[0030] A first heat dissipation fin and a second heat dissipation fin are sequentially mounted in the chip groove, wherein the first heat dissipation fin is mounted on the heat dissipation adhesive layer, and the second heat dissipation fin is disposed on the heat dissipation adhesive layer and bent to extend to a side of the first heat dissipation fin away from the substrate, and a heat dissipation gap is formed between the second heat dissipation fin and the first heat dissipation fin;

[0031] forming a plastic package on the substrate, wherein the plastic package covers the first chip and fills the chip groove, so that the first heat dissipation dummy sheet and the second heat dissipation dummy sheet are covered in the plastic package;

[0032] Solder balls are formed by planting balls on a side of the substrate away from the first chip.

[0033] The beneficial effects of the embodiments of the present invention include:

[0034] The stacked heat dissipation packaging structure provided by an embodiment of the present invention comprises a first chip mounted on a substrate. The first chip adopts a flip-chip structure, with its functional surface connected to the substrate, while the non-functional surface of the first chip is provided with a chip recess. A heat dissipation adhesive layer is provided in the chip recess, which at least covers the bottom wall of the chip recess, thereby achieving better heat extraction. Simultaneously, a first heat dissipation fin and a second heat dissipation fin are also provided in the chip recess. The first heat dissipation fin is mounted on the heat dissipation adhesive layer to directly conduct heat. The second heat dissipation fin is disposed on the heat dissipation adhesive layer and is bent and extends above the first heat dissipation fin. Finally, a plastic encapsulation is performed on the substrate to form a plastic encapsulation body that covers the first chip, the first heat dissipation fin, and the second heat dissipation fin. Compared to the prior art, the stacked heat dissipation packaging structure provided by an embodiment of the present invention, in which both the first heat dissipation fin and the second heat dissipation fin are disposed on the heat dissipation adhesive layer, can quickly extract the heat generated by the first chip and significantly increase the heat dissipation area, thereby improving the heat dissipation effect. At the same time, the second heat dissipation fin is bent and extended above the first heat dissipation fin, and the first heat dissipation fin and the second heat dissipation fin with larger areas can be adopted as much as possible, so as to better utilize the space in the chip groove and further increase the heat dissipation area. In addition, a heat dissipation gap is formed between the first heat dissipation fin and the second heat dissipation fin. This heat dissipation gap can help increase the heat flow of the middle layer outward, avoid heat concentration, and improve heat dissipation performance. Finally, the second heat dissipation fin is arranged above the first heat dissipation fin, which can shorten the heat transfer path of heat to the surface of the plastic package, thereby improving the heat dissipation effect. Therefore, the heat dissipation effect can be improved, and thermal failure can be avoided by exceeding the normal operating temperature range of the chip. And through the provision of the chip groove, the first heat dissipation fin and the second heat dissipation fin can both be accommodated in the chip groove, avoiding that the two upward protrusion heights are too high, and the stacking height can be effectively reduced, which helps to realize the miniaturization of the package structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1a A schematic diagram of a first structural embodiment of a stacked heat dissipation packaging structure provided by an embodiment of the present invention;

[0037] Figure 1b A schematic diagram of a second structure of a stacked heat dissipation packaging structure provided by an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a third structural embodiment of the stacked heat dissipation packaging structure provided by an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of a fourth structural embodiment of the stacked heat dissipation packaging structure provided by an embodiment of the present invention;

[0040] Figure 4 A fifth structural schematic diagram of the stacked heat dissipation packaging structure provided by an embodiment of the present invention;

[0041] Figures 5 to 10 This is a process flow chart of a method for preparing a stacked heat dissipation packaging structure provided by an embodiment of the present invention.

[0042] Icon: 100-stacked heat dissipation packaging structure; 110-substrate; 111-filling glue layer; 120-first chip; 121-chip groove; 122-heat dissipation gap; 123-bump; 130-heat dissipation glue layer; 140-first heat dissipation dummy sheet; 141-first thermal conductive connection line; 142-first metal column; 150-second heat dissipation dummy sheet; 151-base heat dissipation part; 152-bent heat dissipation part; 153-second thermal conductive connection line; 154-second metal column; 155-third thermal conductive connection line; 160-plastic package; 170-second chip; 171-conductive column; 172-static pad; 180-solder ball. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0046] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0047] In addition, the terms "first", "second", etc., if used, are merely used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0048] As disclosed in the background art, the flip-chip stack packaging structure in the prior art easily causes the chip to exceed the normal operating temperature range and thus suffer thermal failure.

[0049] Furthermore, existing solutions have also emerged that utilize external heat dissipation covers to achieve heat dissipation. However, on the one hand, the installation of heat dissipation covers undoubtedly increases the volume of the external packaging structure, resulting in a further increase in stack height, which is not conducive to product miniaturization. On the other hand, heat dissipation covers are typically attached face-to-face to the back side (non-functional side) of the chip, which is far away from the chip's heat source, resulting in limited heat dissipation effect.

[0050] Furthermore, as the size of flip-chip solder joints decreases, the current density and operating temperature they are subjected to increase dramatically, leading to electromigration within the solder joints. Electromigration is the migration of atoms caused by the continuous inelastic collisions of high-density electron flow with atoms in the solder joint. Electromigration can cause hillocks and voids in the interconnected solder joints. Furthermore, the bottom adhesive layer of the stacked chip is affected by electromigration. When the current and temperature gradients increase, not only does it trigger the electromigration effect, but it can also easily lead to defects such as dissolution of the adhesive layer compound and adhesive layer fracture, resulting in damage to the integrity of the adhesive layer solder structure and degradation of mechanical properties, leading to device failure. Therefore, electromigration has become a major challenge to the reliability of electronic packaging and a major obstacle to the continued development of electronic products. Current heat dissipation methods, such as heat dissipation cap structures, are far away from the solder joints and have limited heat dissipation capabilities, making it difficult to truly solve the problems of electromigration and thermal fracture of the bottom adhesive layer.

[0051] In order to solve the above problems, the embodiments of the present invention provide a novel stacked heat dissipation packaging structure and a method for preparing the stacked heat dissipation packaging structure. It should be noted that the features in the embodiments of the present invention can be combined with each other without conflict.

[0052] See also Figure 1a The present invention provides a stacked heat dissipation packaging structure 100 that improves heat dissipation, prevents thermal failure caused by exceeding the normal operating temperature range of the chip, and effectively reduces the stack height, thereby facilitating miniaturization of the packaging structure. Furthermore, it effectively addresses the issues of flip-chip electron migration and thermal fracture of the bottom adhesive layer.

[0053] The stacked heat dissipation packaging structure 100 provided in an embodiment of the present invention includes a substrate 110, a first chip 120, a heat dissipation adhesive layer 130, a first heat dissipation dummy sheet 140, a second heat dissipation dummy sheet 150, a plastic package 160 and solder balls 180. The first chip 120 is mounted on the substrate 110, the functional surface of the first chip 120 is connected to the substrate 110, and the non-functional surface of the first chip 120 is provided with a chip groove 121; the heat dissipation adhesive layer 130 is provided in the chip groove 121, and the heat dissipation adhesive layer 130 at least covers the bottom wall of the chip groove 121; the first heat dissipation dummy sheet 140 and the second heat dissipation dummy sheet 150 are ... Each of the fins 150 is disposed in the chip recess 121. The first heat dissipation fin 140 is mounted on the heat dissipation adhesive layer 130. The second heat dissipation fin 150 is disposed on the heat dissipation adhesive layer 130 and is bent and extended to the side of the first heat dissipation fin 140 away from the substrate 110. A heat dissipation gap 122 is formed between the second heat dissipation fin 150 and the first heat dissipation fin 140. A plastic package 160 is disposed on the substrate 110, covering the first chip 120 and filling the chip recess 121, so that the first heat dissipation fin 140 and the second heat dissipation fin 150 are enclosed within the plastic package 160. Solder balls 180 are disposed on the side of the substrate 110 away from the first chip 120.

[0054] It should be noted that in this embodiment, both the first heat sink fin 140 and the second heat sink fin 150 are supported by a material with good thermal conductivity. Preferably, both the first heat sink fin 140 and the second heat sink fin 150 are metal sheets, such as copper, aluminum, gold, or other metal materials or alloys with good thermal conductivity. Furthermore, the heat dissipation adhesive layer 130 can be made of a thermally conductive adhesive material and can be applied to the bottom wall of the chip recess 121, or to the bottom wall and side walls of the chip recess 121. This allows the heat generated by the chip to be quickly transferred to the first heat sink fin 140 and the second heat sink fin 150, thereby achieving better heat dissipation. Furthermore, the substrate 110 can be a coreless or cored substrate, such as epoxy glass fiber board or Ajinomoto laminate film. Furthermore, the substrate 110 can also be an organic substrate made of an organic material, such as a polyimide substrate. In this embodiment, the substrate 110 can include multiple dielectric layers and multiple wiring layers.

[0055] It is worth noting that both the first heat dissipation fin 140 and the second heat dissipation fin 150 are arranged on the heat dissipation adhesive layer 130, which can quickly conduct away the heat generated by the first chip 120 and greatly increase the heat dissipation area, thereby improving the heat dissipation effect. At the same time, the second heat dissipation fin 150 is bent and extended above the first heat dissipation fin 140, allowing the use of first and second heat dissipation fins 140, 150 with larger areas as much as possible, better utilizing the space in the chip groove 121, and further increasing the heat dissipation area. In addition, a heat dissipation gap 122 is formed between the first heat dissipation fin 140 and the second heat dissipation fin 150. The width of this heat dissipation gap 122 can preferably be between 20μm and 200μm, which can help increase the outward flow of heat from the middle layer, avoid heat concentration, and improve heat dissipation performance. Finally, the second heat dissipation fin 150 is arranged above the first heat dissipation fin 140, which can shorten the heat transfer path from the heat transfer to the surface of the plastic package 160, thereby improving the heat dissipation effect. Therefore, the heat dissipation effect can be improved, and thermal failure caused by exceeding the normal operating temperature range of the chip can be avoided. Furthermore, the provision of the chip recess 121 allows both the first heat dissipation fin 140 and the second heat dissipation fin 150 to be accommodated within the chip recess 121, preventing them from protruding excessively upwards. This effectively reduces the stacking height and facilitates miniaturization of the package structure. The chip recess 121 also thins the first chip 120, reducing the heat conduction path from the functional surface of the first chip 120 and allowing the first and second heat dissipation fins 140 and 150 to be closer to the functional surface of the first chip 120. Furthermore, the first and second heat dissipation fins 140 and 150 can be used to better dissipate heat from the bottom of the first chip 120, effectively resolving the issues of flip-chip electron migration and thermal fracture of the bottom adhesive layer.

[0056] In some embodiments, the second heat dissipation fin 150 includes an L-shaped base heat dissipation portion 151 and a bent heat dissipation portion 152. The base heat dissipation portion 151 is attached to the heat dissipation adhesive layer 130 and spaced apart from the sidewall of the first heat dissipation fin 140. The bent heat dissipation portion 152 bends and extends from the base heat dissipation portion 151 toward the side of the first heat dissipation fin 140 away from the substrate 110 and is spaced apart from the top surface of the first heat dissipation fin 140, thereby forming an L-shaped heat dissipation gap 122. Specifically, the L-shape of the second heat dissipation fin 150 allows it to be directly connected to the heat dissipation adhesive layer 130 via the base heat dissipation portion 151, thereby quickly directing heat to the bent heat dissipation portion 152. Furthermore, the L-shaped second heat dissipation fin 150 provides a larger heat dissipation area, allowing it to be more effectively offset from the first heat dissipation fin 140, thereby better utilizing the space in the chip recess 121.

[0057] In some embodiments, a first thermally conductive connection line 141 is provided on the first heat dissipation fin 140. The first thermally conductive connection line 141 is spaced apart from the second heat dissipation fin 150 and connected to the heat dissipation adhesive layer 130. Furthermore, a second thermally conductive connection line 153 is provided on the side of the second heat dissipation fin 150 away from the substrate 110. The second thermally conductive connection line 153 is spaced apart from both the first heat dissipation fin 140 and the first thermally conductive connection line 141 and connected to the heat dissipation adhesive layer 130. Specifically, both the first thermally conductive connection line 141 and the second thermally conductive connection element are formed by a wire bonding process and are made of metal. Wire bonding can further improve heat dissipation performance.

[0058] It should be noted that the heat dissipation adhesive layer 130 here can, on the one hand, serve as an adhesive layer to fix the first heat dissipation pseudo-sheet 140 and the second heat dissipation pseudo-sheet 150, and on the other hand, can also serve as a wire bonding welding layer to realize the wire bonding process, thereby avoiding the need for additional design of the metal layer structure in the traditional process and omitting the metal layer, thereby thinning the stacking thickness and reducing stress.

[0059] In some embodiments, first thermally conductive connecting wires 141 are disposed on both sides of the first heat dissipation fin 140. The first thermally conductive connecting wires 141 adjacent to the second heat dissipation fin 150 extend to the heat dissipation gap 122. Second thermally conductive connecting wires 153 are disposed on both sides of the second heat dissipation fin 150. Specifically, multiple first thermally conductive connecting wires 141 can be disposed on both sides of the first heat dissipation fin 140, and multiple second thermally conductive connecting wires 153 can be disposed on both sides of the second heat dissipation fin 150. By bonding wires on both sides, the heat dissipation effect is further improved.

[0060] It should be noted that in this embodiment, the first thermally conductive connection line 141 of the base heat dissipation portion 151 close to the second heat dissipation dummy sheet 150 can extend into the heat dissipation gap 122. On the one hand, it can improve the heat dissipation effect, and on the other hand, it can enhance the capillary action in the heat dissipation gap 122, so that the plastic encapsulation material can flow better in the heat dissipation gap 122, thereby completely filling the heat dissipation gap 122 and avoiding the formation of voids.

[0061] In some embodiments, the bonding height of the second thermally conductive wire 153 relative to the heatsink adhesive layer 130 is greater than the depth of the chip recess 121 relative to the heatsink adhesive layer 130, while the bonding height of the first thermally conductive wire 141 relative to the heatsink adhesive layer 130 is less than the depth of the chip recess 121 relative to the heatsink adhesive layer 130. Specifically, the bonding height refers to the distance between the highest point of the bonding wire and the heatsink adhesive layer 130, while the depth of the chip recess 121 refers to the distance between the surrounding surface of the chip recess 121 and the heatsink adhesive layer 130. The bonding height of the second thermally conductive wire 153 is higher than the first chip 120, while the bonding height of the first thermally conductive wire 141 is within the chip recess 121. This effectively prevents interference between the first thermally conductive wire 141 and the second thermally conductive wire 153, which could affect the smooth execution of the bonding process. Furthermore, the second thermally conductive wire 153 can partially extend outside the chip recess 121, thereby further expanding the heat conduction range, further shortening the heat conduction path to the surface of the plastic package 160, and improving heat dissipation.

[0062] In some embodiments, the height of the second heat dissipation fin 150 relative to the heat dissipation adhesive layer 130 is less than the depth of the chip recess 121 relative to the heat dissipation adhesive layer 130, and the second thermally conductive connecting wire 153 and the first thermally conductive connecting wire 141 are both enclosed within the plastic package 160. Specifically, the second heat dissipation fin 150 and the first heat dissipation fin 140 are both completely contained within the chip recess 121, thereby preventing the second heat dissipation fin 150 from protruding from the first chip 120 and reducing the stacked package height. Furthermore, the first thermally conductive connecting wire 141 and the second thermally conductive connecting wire 153 are both enclosed within the plastic package 160, thereby enhancing the bonding strength between the plastic package 160, the heat dissipation adhesive layer 130, and the first chip 120, thereby preventing delamination of the plastic package 160.

[0063] In some embodiments, a filler layer 111 is further disposed between the substrate 110 and the first chip 120. Bumps 123 are disposed on the functional surface of the first chip 120, and the bumps 123 are connected to the substrate 110. The filler layer 111 covers the bumps 123. Specifically, the bottom of the first chip 120 is protected by the bottom filler. Furthermore, the provision of the chip groove 121 and the heat dissipation provided by the first and second heat dissipation fins 140 and 150 effectively prevent the filler layer 111 from breaking due to heat, thereby ensuring that the filler layer 111 protects the internal solder joint structure of the bumps 123.

[0064] See also Figure 1b In some embodiments, a third heat-conducting connecting line 155 is further disposed within the heat dissipation gap 122. The third heat-conducting connecting line 155 is disposed in an arched shape on the surface of the first heat dissipation fin 140 and / or the second heat dissipation fin 150. Specifically, the third heat-conducting connecting line 155 can be disposed on a side of the first heat dissipation fin 140 facing away from the substrate 110, with both ends of the third heat-conducting connecting line 155 connected to the surface of the horizontally disposed first heat dissipation fin 140, thereby forming an arched distribution of the third heat-conducting connecting line 155. Multiple third heat-conducting connecting lines 155 are provided, and the plurality of third heat-conducting connecting lines 155 are distributed along the same straight line. The provision of the third heat-conducting connecting line 155 can, on the one hand, form a mold flow channel, facilitating the flow of the molding compound within the heat dissipation gap 122 and improving the molding compound filling effect. On the other hand, the third heat-conducting connecting line 155 can enhance the heat dissipation effect within the heat dissipation gap 122.

[0065] See also Figure 2 In some embodiments, a first metal pillar 142 is further disposed between the first heat dissipation fin 140 and the second heat dissipation fin 150. The bottom end of the first metal pillar 142 is connected to the side of the first heat dissipation fin 140 away from the substrate 110, and the top end of the first metal pillar 142 is connected to the second heat dissipation fin 150. Specifically, there may be multiple first metal pillars 142, evenly distributed within the heat dissipation gap 122. Each first metal pillar 142 extends vertically, with the bottom end of each first metal pillar 142 connected to the top surface of the first heat dissipation fin 140 and the top end of the first metal pillar 142 connected to the bent heat dissipation portion 152 of the second heat dissipation fin 150. The first metal pillars 142 are preferably copper pillars. The provision of the first metal pillars 142 not only improves the heat dissipation performance of the heat dissipation gap 122 but also provides support for the second heat dissipation fin 150. Furthermore, the first metal pillars 142 can also enhance the capillary effect inside the heat dissipation gap 122 , thereby ensuring that the molding compound can be smoothly filled into the heat dissipation gap 122 and avoiding the formation of voids.

[0066] See also Figure 3In some embodiments, the stacked heat dissipation packaging structure 100 further includes a second chip 170. The second chip 170 is spaced apart from the first chip 120 on a side away from the substrate 110 and is encapsulated by the plastic package 160. The functional surface of the second chip 170 faces the first chip 120. Conductive pillars 171 are provided on the edge of the functional surface of the second chip 170. The conductive pillars 171 extend and connect to the substrate 110 and are spaced apart from the first chip 120. Specifically, the second chip 170 is spaced apart from the second thermally conductive connection line 153. The conductive pillars 171 can be provided on both sides of the bottom of the second chip 170 and extend downward to the wiring pads on the substrate 110, thereby achieving electrical connection between the conductive pillars and the substrate 110. By providing the second chip 170, the number of stacking chips and the chip density can be increased, and the second chip 170 can be directly connected to the substrate 110, which improves the transmission effect.

[0067] Furthermore, a second metal pillar 154 is provided in the middle of the functional surface of the second chip 170. The second metal pillar 154 extends and connects to the side surface of the second heat dissipation fin 150 facing away from the first metal pillar 142. Specifically, the second metal pillar 154 can be a copper pillar, and there can be multiple second metal pillars 154, evenly distributed between the second chip 170 and the bent heat dissipation portion 152 of the second heat dissipation fin 150. Each second metal pillar 154 extends vertically, with the bottom end of each second metal pillar 154 connected to the top surface of the bent heat dissipation portion 152 of the second heat dissipation fin 150, and the top end of each second metal pillar 154 connected to the middle of the functional surface of the second chip 170. The provision of the second metal pillar 154 not only improves the heat dissipation performance of the bottom of the second chip 170, but also provides support, thereby better supporting the second chip 170 and effectively preventing the solder bumps on the bottom of the second chip 170 from collapsing and contacting the second thermally conductive connection line 153. Furthermore, the second metal pillars 154 can also enhance the capillary effect inside the gap, thereby ensuring that the molding compound can be smoothly filled into the bottom space of the second chip 170 to avoid the formation of voids.

[0068] Furthermore, there are multiple first metal pillars 142 and multiple second metal pillars 154, and the multiple first metal pillars 142 correspond to the multiple second metal pillars 154. Specifically, the multiple first metal pillars 142 correspond to the multiple second metal pillars 154, thereby making the support structure more stable and reliable. In addition, the first metal pillars 142 and the second metal pillars 154 can be prepared and formed on the second heat dissipation fin 150 in advance, thereby facilitating mounting.

[0069] See also Figure 4In some embodiments, the functional surface of the second chip 170 is further provided with an electrostatic pad 172. The electrostatic pad 172 is electrically connected to the conductive pillar 171 and is also connected to the second metal pillar 154. Specifically, a ground circuit is formed on the functional surface of the second chip 170. This ground circuit is connected to the ground circuit of the substrate 110 via the conductive pillar 171, thereby grounding the second metal pillar 154. The provision of the electrostatic pad 172 enables grounding of the second metal pillar 154, the second heat sink fin 150, and the first heat sink fin 140. This dissipates static electricity from the first and second heat sink fins 140 and 150, preventing static electricity from the first and second heat sink fins 140 and 150 from penetrating the second chip 170 and first chip 120, thereby damaging the second and first chips 170 and 120.

[0070] The present invention further provides a method for preparing a stacked heat dissipation package structure 100, which is used to prepare the stacked heat dissipation package structure 100 as described in the aforementioned embodiment. The preparation method includes:

[0071] S1: Provide a substrate 110.

[0072] Specifically, a substrate 110 is first used. This substrate can be a coreless substrate or a cored substrate, such as an epoxy glass fiber board or an Ajinomoto laminate film. Alternatively, substrate 110 can be an organic substrate made of an organic material, such as a polyimide substrate. In this embodiment, substrate 110 can include multiple dielectric layers and multiple wiring layers, where the multiple wiring layers are metal layers distributed within the multiple dielectric layers.

[0073] S2 : mounting the first chip 120 on the substrate 110 , wherein the functional surface of the first chip 120 is connected to the substrate 110 .

[0074] See also Figure 5 Specifically, after the first flip-chip chip 120 is mounted on the substrate 110, the bumps 123 can be welded using a convergence process, and then a filling layer 111 can be formed using a dispensing process to protect the bottom welding structure, and finally the filling layer 111 can be fixed by baking.

[0075] S3 : forming a chip groove 121 on the non-functional surface of the first chip 120 .

[0076] See also Figure 6 Specifically, a chip groove 121 can be formed on the non-functional surface (back surface) of the first chip 120 through laser grooving or chemical etching. The bottom filler layer 111 can prevent contamination of the solder joint. Finally, a cleaning process is used to remove residue from the surface of the substrate 110. This cleaning process can be dry ice cleaning or plasma cleaning.

[0077] S4 : forming a heat dissipation adhesive layer 130 in the chip cavity 121 , wherein the heat dissipation adhesive layer 130 at least covers the bottom wall of the chip cavity 121 .

[0078] See also Figure 7 Specifically, a dispensing process can be used to dispense glue on the bottom wall of the chip groove 121. The glue can be silver paste or thermally conductive glue, and the glue can be filled with thermally conductive particles, such as nano silver / copper and other metals. Here, the heat dissipation glue layer 130 is a non-metallic layer.

[0079] S5: A first heat dissipation fin 140 and a second heat dissipation fin 150 are sequentially mounted in the chip groove 121, wherein the first heat dissipation fin 140 is mounted on the heat dissipation adhesive layer 130, and the second heat dissipation fin 150 is arranged on the heat dissipation adhesive layer 130 and bent to extend to a side of the first heat dissipation fin 140 away from the substrate 110, and a heat dissipation gap 122 is formed between the second heat dissipation fin 150 and the first heat dissipation fin 140.

[0080] Please continue to see Figure 8 Specifically, after dispensing the heat dissipation adhesive layer 130, the first heat dissipation fin 140 and the second heat dissipation fin 150 can be mounted. Both the first heat dissipation fin 140 and the second heat dissipation fin 150 can be prepared in advance. The width of the heat dissipation gap 122 can be between 20 μm and 200 μm. After the first heat dissipation fin 140 and the second heat dissipation fin 150 are mounted, the heat dissipation adhesive layer 130 can be fixed by baking.

[0081] It is worth noting that the first heat dissipation fin 140 and the second heat dissipation fin 150 can be sequentially mounted on the heat dissipation adhesive layer 130. After mounting the first heat dissipation fin 140, a wire bonding process can be used to form the first thermal conductive connection line 141. After mounting the second heat dissipation fin 150, a wire bonding process can be used to form the second thermal conductive connection line 153.

[0082] S6 : forming a plastic package 160 on the substrate 110 . The plastic package 160 covers the first chip 120 and fills the chip groove 121 , so that the first heat dissipation fin 140 and the second heat dissipation fin 150 are covered in the plastic package 160 .

[0083] See also Figure 9 Specifically, the stacked structure is filled and protected with the plastic packaging body 160 using a plastic packaging process, thereby forming the plastic packaging body 160 .

[0084] S7 : forming solder balls 180 on a side of the substrate 110 away from the first chip 120 .

[0085] See also Figure 10Specifically, a ball planting process can be used to form solder balls 180 on the back side of the substrate 110, and then a cutting process can be used to cut the substrate 110 into individual products.

[0086] In summary, the stacked heat dissipation packaging structure 100 and its preparation method provided by the embodiments of the present invention include a first chip 120 mounted on a substrate 110. The first chip 120 adopts a flip-chip structure, with its functional surface connected to the substrate 110, while the non-functional surface of the first chip 120 is provided with a chip recess 121. A heat dissipation adhesive layer 130 is provided in the chip recess 121, and the heat dissipation adhesive layer 130 at least covers the bottom wall of the chip recess 121, thereby achieving better heat dissipation. Furthermore, a first heat dissipation fin 140 and a second heat dissipation fin 150 are also provided in the chip recess 121. The first heat dissipation fin 140 is mounted on the heat dissipation adhesive layer 130 to directly conduct heat. The second heat dissipation fin 150 is disposed on the heat dissipation adhesive layer 130 and is bent and extended above the first heat dissipation fin 140. Finally, a plastic package 160 is formed on the substrate 110 to cover the first chip 120, the first heat dissipation fin 140, and the second heat dissipation fin 150. Compared to the prior art, the stacked heat dissipation packaging structure 100 provided in the embodiment of the present invention has both the first heat dissipation fin 140 and the second heat dissipation fin 150 disposed on the heat dissipation adhesive layer 130. This allows for rapid heat dissipation from the first chip 120 and significantly increases the heat dissipation area, thereby enhancing the heat dissipation effect. Furthermore, the second heat dissipation fin 150 is bent and extended above the first heat dissipation fin 140, allowing for the use of larger first and second heat dissipation fins 140, 150 as much as possible, better utilizing the space within the chip recess 121 and further increasing the heat dissipation area. Furthermore, a heat dissipation gap 122 is formed between the first and second heat dissipation fins 140, 150. This gap 122 helps increase the outward flow of heat from the intermediate layer, preventing heat concentration and improving heat dissipation performance. Finally, the second heat dissipation fin 150 is disposed above the first heat dissipation fin 140, shortening the heat transfer path from the heat transfer to the surface of the plastic package 160, thereby enhancing the heat dissipation effect. Consequently, the heat dissipation effect is enhanced, preventing thermal failure caused by exceeding the normal operating temperature range of the chip. Furthermore, by providing the chip groove 121 , both the first heat dissipation fin 140 and the second heat dissipation fin 150 can be accommodated in the chip groove 121 , preventing the two from protruding upward too high, effectively reducing the stacking height, and contributing to miniaturization of the packaging structure.

[0087] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A stacked heat dissipation packaging structure, characterized in that: include: substrate; a first chip mounted on the substrate, wherein a functional surface of the first chip is connected to the substrate, and a chip groove is provided on a non-functional surface of the first chip; A heat dissipation adhesive layer is provided in the chip groove, wherein the heat dissipation adhesive layer at least covers the bottom wall of the chip groove; A first heat dissipation fin and a second heat dissipation fin are provided in the chip groove, wherein the first heat dissipation fin is attached to the heat dissipation adhesive layer, and the second heat dissipation fin is provided on the heat dissipation adhesive layer and is bent and extended to a side of the first heat dissipation fin away from the substrate, with a heat dissipation gap formed between the second heat dissipation fin and the first heat dissipation fin; A plastic package is provided on the substrate, the plastic package covers the first chip and fills the chip groove, so that the first heat dissipation dummy sheet and the second heat dissipation dummy sheet are covered in the plastic package; a solder ball disposed on a side of the substrate facing away from the first chip; The second heat dissipation fin includes a base heat dissipation portion and a bent heat dissipation portion distributed in an L-shape. The base heat dissipation portion is attached to the heat dissipation adhesive layer and is spaced apart from the side wall of the first heat dissipation fin. The bent heat dissipation portion is bent and extended from the base heat dissipation portion toward a side of the first heat dissipation fin away from the substrate and is spaced apart from the top side surface of the first heat dissipation fin, so that the heat dissipation gap is L-shaped.

2. The stacked heat dissipation packaging structure according to claim 1, wherein: A first heat-conducting connecting line is provided on the first heat-dissipating dummy sheet. The first heat-conducting connecting line is spaced apart from the second heat-dissipating dummy sheet and is connected to the heat-dissipating adhesive layer.

3. The stacked heat dissipation packaging structure according to claim 2, wherein: A second heat-conducting connecting line is provided on a side of the second heat-dissipating fin away from the substrate. The second heat-conducting connecting line is spaced apart from both the first heat-dissipating fin and the first heat-conducting connecting line and is connected to the heat-dissipating adhesive layer.

4. The stacked heat dissipation packaging structure according to claim 3, wherein: The first heat-conducting connecting lines are arranged on both sides of the first heat-dissipating fin, and the first heat-conducting connecting lines close to the second heat-dissipating fin extend to the heat-dissipating gap; The second heat-conducting connecting wires are arranged on both sides of the second heat dissipation fin.

5. The stacked heat dissipation packaging structure according to claim 3, wherein: The bonding height of the second thermally conductive connection line relative to the heat dissipation adhesive layer is greater than the depth of the chip groove relative to the heat dissipation adhesive layer, and the bonding height of the first thermally conductive connection line relative to the heat dissipation adhesive layer is less than the depth of the chip groove relative to the heat dissipation adhesive layer.

6. The stacked heat dissipation packaging structure according to claim 5, characterized in that: The height of the second heat dissipation dummy sheet relative to the heat dissipation adhesive layer is smaller than the depth of the chip groove relative to the heat dissipation adhesive layer, and the second heat conductive connecting line and the first heat conductive connecting line are both covered in the plastic package.

7. The stacked heat dissipation packaging structure according to claim 1, wherein: A filling adhesive layer is further provided between the substrate and the first chip. The functional surface of the first chip is provided with bumps, the bumps are connected to the substrate, and the filling adhesive layer is coated outside the bumps.

8. The stacked heat dissipation packaging structure according to claim 1, wherein: A third heat-conducting connecting line is further provided in the heat-dissipating gap. The third heat-conducting connecting line is provided in an arch shape on the surface of the first heat-dissipating fin and / or the second heat-dissipating fin.

9. The stacked heat dissipation packaging structure according to claim 1, wherein: A first metal column is further provided between the first heat dissipation fin and the second heat dissipation fin. The bottom end of the first metal column is connected to the side of the first heat dissipation fin away from the substrate, and the top end of the first metal column is connected to the second heat dissipation fin.

10. The stacked heat dissipation packaging structure according to claim 9, wherein: The stacked heat dissipation packaging structure also includes a second chip, which is spaced apart on a side of the first chip away from the substrate and is coated with the plastic package, and the functional surface of the second chip faces the first chip. A conductive column is provided at the edge of the functional surface of the second chip, and the conductive column extends and is connected to the substrate and is spaced apart from the first chip.

11. The stacked heat dissipation packaging structure according to claim 10, wherein: A second metal column is further provided in the middle of the functional surface of the second chip. The second metal column is extended and connected to a side surface of the second heat dissipation fin facing away from the first metal column.

12. The stacked heat dissipation packaging structure according to claim 11, wherein: The functional surface of the second chip is further provided with an electrostatic pad, the electrostatic pad is electrically connected to the conductive column, and the electrostatic pad is connected to the second metal column.

13. The stacked heat dissipation packaging structure according to claim 11, wherein: There are a plurality of the first metal pillars and a plurality of the second metal pillars, and the plurality of the first metal pillars and the plurality of the second metal pillars correspond to each other.

14. A method for preparing a stacked heat dissipation packaging structure, for preparing the stacked heat dissipation packaging structure according to claim 1, characterized in that: The preparation method comprises: providing a substrate; Mounting a first chip on the substrate, wherein a functional surface of the first chip is connected to the substrate; forming a chip groove on a non-functional surface of the first chip; forming a heat dissipation adhesive layer in the chip groove, wherein the heat dissipation adhesive layer at least covers the bottom wall of the chip groove; A first heat dissipation fin and a second heat dissipation fin are sequentially mounted in the chip groove, wherein the first heat dissipation fin is mounted on the heat dissipation adhesive layer, and the second heat dissipation fin is disposed on the heat dissipation adhesive layer and bent to extend to a side of the first heat dissipation fin away from the substrate, and a heat dissipation gap is formed between the second heat dissipation fin and the first heat dissipation fin; forming a plastic package on the substrate, wherein the plastic package covers the first chip and fills the chip groove, so that the first heat dissipation dummy sheet and the second heat dissipation dummy sheet are covered in the plastic package; Solder balls are formed by planting balls on a side of the substrate away from the first chip.

Images