CN-121985827-A - Packaging structure of three-dimensional stacked chip and air-cooling heat dissipation method

CN121985827ACN 121985827 ACN121985827 ACN 121985827ACN-121985827-A

Abstract

The invention relates to a packaging structure of three-dimensional stacked chips and an air cooling heat dissipation method, wherein the structure comprises a three-dimensional stacked body formed by vertically stacking at least two layers of functional chips, micro-interconnection structure arrays used for electrical interconnection among layers form dense micro-needle ribs in interlayer gaps formed by bonding, and a micro air cooling generation unit integrated on the side surface of the stacked body generates cooling air flow perpendicular to the stacking direction. The air flow is parallel to the plane of the chip, transversely penetrates through the microneedle rib array among layers, and achieves direct forced convection heat dissipation on the surface of each layer of chip. According to the invention, the interconnection structure is functionalized into the heat dissipation micro-needle rib, an independent heat dissipation part is not required to be additionally arranged, the heat dissipation efficiency and uniformity are obviously improved on the premise of keeping the packaging compactness, and the heat dissipation problem of the middle layer chip in the three-dimensional stacking is effectively solved. Meanwhile, the method has good process compatibility and high reliability, and is suitable for a high-power density three-dimensional integrated system.

Inventors

LI AO
LIU SHULI
WANG GANG
JI YONG

Assignees

中国电子科技集团公司第五十八研究所

Dates

Publication Date: 20260505
Application Date: 20260130

Claims (10)

1. The utility model provides a packaging structure of three-dimensional stacked chip, and forced air cooling heat dissipation in side direction based on little interconnect structure microneedle rib, its characterized in that includes: The three-dimensional stacking body is formed by vertically stacking at least two layers of functional chips on a packaging substrate or an intermediate layer, and the chips of each layer realize electrical interconnection and mechanical support through a micro interconnection structure array and form interlayer gaps between adjacent chips; The micro-interconnection structure array is arranged in the interlayer gap to form a micro-needle rib structure for promoting cooling air flow and chip surface heat exchange; At least one miniature air cooling generating unit integrated on at least one side surface of the three-dimensional stacking body and used for generating cooling air flow vertical to the stacking plane of the chips; The cooling air flow is configured to be parallel to the plane of the chip in the whole process, transversely flows through the microneedle rib structures among the layers, and achieves direct forced convection heat dissipation on the surface of the chip.
2. The three-dimensional stacked chip packaging structure of claim 1, wherein the micro-needle rib structures are arranged in a staggered manner in the interlayer gaps, preferably in a hexagonal close-packed or quincuncial arrangement.
3. The three-dimensional stacked chip packaging structure of claim 1, wherein the micro-needle rib structures are arranged in a gradient arrangement mode in the interlayer gaps, the arrangement density and/or the structure size of the micro-interconnection structures are continuously or sectionally changed along the flowing direction of cooling air flow, and the gradient arrangement is optimally designed according to the chip heat source distribution.
4. The three-dimensional stacked chip packaging structure of claim 1, wherein the micro-interconnect structure is a spherical or columnar conductive interconnect structure comprising at least one of micro-bumps, copper pillars, and solder balls.
5. The three-dimensional stacked chip package structure of claim 1, wherein the micro air-cooling generating unit is a piezoelectric fan that generates cooling air flow by using inverse piezoelectric effect vibration, or other micro fans.
6. The three-dimensional stacked chip packaging structure of claim 1, wherein the surface of the micro-interconnect structure is roughened or coated with a functional coating of high thermal conductivity or high emissivity.
7. The three-dimensional stacked chip packaging structure of claim 1, wherein the number of the micro air cooling generating units is two, and the micro air cooling generating units are respectively arranged on opposite sides of the three-dimensional stacked body to form opposite air flows.
8. The three-dimensional stacked chip packaging structure of claim 1, wherein the chips in the three-dimensional stack are bare chips or packaged chips.
9. The three-dimensional stacked chip packaging structure of claim 1, wherein the micro air-cooled generator is integrated on the side of the stacked body in a bonding, embedded mounting, additive manufacturing or integrated forming manner with the packaging structure, and is powered by a packaging internal power distribution network.
10. A lateral forced air cooling heat dissipation method is characterized by comprising the following steps: Step S1, designing layout of a micro-interconnection structure array to form an interlayer micro-needle rib structure after chip bonding; S2, preparing the micro-interconnection structure on a chip bonding surface; s3, aligning and bonding the chips to form a three-dimensional stacked body with interlayer microneedle rib flow channels; S4, integrating a miniature air cooling generating unit on at least one side surface of the three-dimensional stacked body, so that the air outlet direction of the miniature air cooling generating unit is aligned to the interlayer gap; And S5, driving the miniature air cooling generation unit to generate transverse cooling air flow to penetrate through the microneedle rib structure between the layers, so as to realize embedded forced convection heat dissipation of the stacked chips.

Description

Packaging structure of three-dimensional stacked chip and air-cooling heat dissipation method Technical Field The invention relates to the technical field of integrated circuit packaging and thermal management, in particular to a packaging structure of three-dimensional stacked chips and an air cooling heat dissipation method, which are particularly suitable for heat dissipation of compact electronic devices formed by stacked packaging. Background With the development of microelectronic technology, multi-chip modules (MCM) and three-dimensional stacked packages are becoming popular, and although the three-dimensional stacked packages can solve the bottleneck problem of the conventional two-dimensional packages, with the increase of integration level, the heating problem of the three-dimensional stacked packages is becoming more and more serious due to the high-density integrated active devices, and the heat generated by stacking internal chips is difficult to be effectively conducted out through the conventional top heat dissipation path, so that local high-temperature hot spots are formed. In addition, the complex packaging structure and materials can cause large thermal stress in the package due to uneven heat distribution, and the continuous improvement of the chip performance and the system reliability are seriously restricted. In the three-dimensional stacked package, heat is mainly transferred through the vertical direction. The existing heat dissipation scheme has obvious limitations that a heat sink is attached to the back of a packaging structure, heat is transferred to the environment or the atmosphere of a system, the interface of a plurality of layers of materials is increased in composite thermal resistance due to the fact that a plurality of layers of chips are arranged between the heat sink and the packaging structure, the heat is difficult to transfer efficiently, the heat dissipation effect on the bottom layer of chips is poor, and the heat conduction to the surface of the packaging structure is limited by the density of the through holes and the heat conduction performance of the materials due to the fact that the heat through holes are arranged in the chips or between the chips, and the space utilization rate is low. The heat dissipation fins are attached to the side surfaces of the stacks, so that the package size is increased, the thermal resistance is still large, and the micro-channels are etched in the silicon intermediate layer or the chip to carry out liquid cooling, so that the process is complex, the cost is high, and the leakage risk exists. In addition, as disclosed in patent CN106356344a, an "air-cooled heat dissipation structure based on three-dimensional stacked package" is formed by processing vertical through holes in a multilayer substrate to form an "air duct" penetrating up and down, and driving air flow vertically through these through holes by means of a fan at the top of the package to achieve heat dissipation. The scheme has the following limitations that (1) the construction of the air duct depends on the additional processing of through holes on a substrate, the process steps are increased, meanwhile, the function of the packaging body is possibly damaged by opening holes, the universality of the heat dissipation scheme is reduced, (2) the air flow direction is vertical to the plane of the chip, the heat flowing through the wall surface of the through holes is mainly taken away, the heat conduction path between the heat source of the chip and the interconnection structure is insufficient and direct, and (3) the integral structure of the core heating area (the bare chip or the packaging chip) in the flow field is difficult to design, so that the heat exchange efficiency with air is further reduced. In particular, the solution cannot effectively solve the heat dissipation problem of the middle layer chip in the three-dimensional stack, because the vertical airflow path cannot uniformly cover the surfaces of the chips of each layer, resulting in the middle layer having a significantly higher temperature than the top and bottom chips. The three-dimensional stacked chip side forced air cooling heat dissipation structure using the interconnection structure as the micro-needle rib can efficiently utilize limited packaging space on the premise of not remarkably increasing process complexity, directly and efficiently carry heat away from the inside of the three-dimensional stack, and ensure that the integrated circuit works at a specified temperature. Therefore, the problems of long heat dissipation path, low efficiency, complex structure or increased volume existing in the existing three-dimensional stacked chip heat dissipation scheme are solved. There is a need to provide a solution for direct heat dissipation from the inside and sides of the stack, by designing the functionalized interconnect structure as a heat dissipating microneedle rib, and integrating a miniature