High heat dissipation package structure

Abstract

The utility model provides a high heat dissipation packaging structure, it includes substrate, chip, heat conduction metal sheet and heat dissipation cover, the functional surface of chip is inverted in substrate surface, heat conduction metal sheet is located chip top, heat dissipation cover is installed in substrate surface, and the chip and heat conduction metal sheet are covered. Further, the non -functional surface of chip is equipped with first metal layer, first metal layer includes the first side wall metal layer of surrounding setting all around, and first side wall metal layer surrounds heat conduction metal sheet, the inner surface of heat dissipation cover is equipped with second metal layer, and second metal layer covers the surface of first metal layer that has pasted heat conduction metal sheet. The utility model avoids the mixture of the gas of flux volatilization and the molten heat conduction metal sheet in the reflow high temperature process, and along with the flux gas being taken out a lot under the condition of vacuum, causes the coverage of heat conduction metal sheet on the chip surface of back gold not to be high and a large number of cavity problem, has improved the heat dissipation effect of packaging structure greatly.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor packaging technology, and specifically relates to a high heat dissipation packaging structure and a stacked structure with multiple high heat dissipation packaging structures. Background Technology

[0002] Traditional packaging requires the use of a metal heat sink for heat conduction. The metal heat sink absorbs heat quickly and dissipates heat relatively quickly, thus achieving rapid heat dissipation through heat transfer.

[0003] In general, a thermally conductive metal layer (interface thermal conductive material) is soldered between the electronic component (chip) and the heat sink to more effectively conduct the heat generated by the electronic component to the heat sink, and then dissipate it into the surrounding air. The thermal conductivity of the interface thermal conductive material determines whether the heat generated by the electronic component can be effectively dissipated.

[0004] Thermally conductive materials are typically indium or indium-silver alloys. Currently, indium sheets are used as interface thermally conductive materials and are soldered together with gold-backed chips and gold-backed heat sinks using flux. During the high-temperature reflow process, the flux volatilizes, generating gas that mixes with the molten interface thermally conductive material. Under vacuum conditions, this mixture is easily carried away with the flux gas, resulting in abnormal voids on the thermally conductive metal solder surface and low thermally conductive metal coverage, which significantly reduces heat dissipation.

[0005] Therefore, a new high heat dissipation packaging structure is urgently needed. Utility Model Content

[0006] The purpose of this invention is to provide a high heat dissipation packaging structure to solve the problem that in the existing packaging structure, the flux volatilization during the reflow process causes abnormal voids in the thermally conductive metal welding surface, resulting in low thermally conductive metal coverage and affecting the heat dissipation performance of the packaging structure.

[0007] To achieve the above objectives, this utility model provides a high heat dissipation packaging structure, which includes a substrate, a chip, a thermally conductive metal sheet, and a heat sink. The functional side of the chip is flip-chip mounted on the surface of the substrate, the thermally conductive metal sheet is disposed above the chip, and the heat sink is mounted on the surface of the substrate, covering the chip and the thermally conductive metal sheet. Further, the non-functional side of the chip is provided with a first metal layer, which includes a first sidewall metal layer surrounding the thermally conductive metal sheet. The inner surface of the heat sink is provided with a second metal layer, which covers the surface of the first metal layer on which the thermally conductive metal sheet is mounted.

[0008] Preferably, the first sidewall metal layer is provided with a plurality of first micropores.

[0009] Preferably, the first metal layer further includes a bottom metal layer, which is connected to the first sidewall metal layer.

[0010] Preferably, the second metal layer includes a second sidewall metal layer and a top metal layer connected together, wherein the second sidewall metal layer surrounds the heat-conducting metal sheet.

[0011] Preferably, the second sidewall metal layer is provided with a plurality of second micropores.

[0012] Preferably, the diameters of the first and second micropores are 50±5μm.

[0013] Preferably, the first metal layer and the second metal layer are made of gold and have a thickness of 200-500 μm.

[0014] Preferably, the thermally conductive metal sheet is an indium sheet.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The high heat dissipation packaging structure disclosed in this utility model avoids the problem of insufficient coverage of the heat-conducting metal sheet and a large number of voids caused by the gas generated by flux volatilization and the molten heat-conducting metal sheet during the high-temperature reflow process, which is caused by a large amount of flux gas being carried out under vacuum conditions. This greatly improves the heat dissipation effect of the packaging structure. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the high heat dissipation packaging structure of this utility model without the heat dissipation cover installed; Figure 2 This is a schematic diagram of a high heat dissipation packaging structure; Figure 3 This is a schematic diagram of the chip structure; Figure 4 This is a schematic diagram of the structure of the first metal layer; Figure 5 This is a schematic diagram of the structure of the second metal layer.

[0017] Reference numerals: Substrate 1; Chip 2; Functional surface 201; Non-functional surface 202; Thermally conductive metal sheet 3; Heat sink 4; Filler adhesive layer 5; First metal layer 6; First sidewall metal layer 601; Bottom metal layer 602; First micro pore 603; Second metal layer 7; Second sidewall metal layer 701; Top metal layer 702; Second micro pore 703. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings.

[0019] like Figures 1 to 5 As shown, this utility model provides a high heat dissipation packaging structure, which includes a substrate 1, a chip 2, a thermally conductive metal sheet 3, and a heat sink 4. The functional surface 201 of the chip 2 is flip-chip mounted on the surface of the substrate 1. An insulating filler layer 5 is provided at the connection structure between the bottom of the chip 2 and the substrate 1. The thermally conductive metal sheet 3 is disposed above the chip 2. The heat sink 4 is mounted on the surface of the substrate 1, covering the chip 2 and the thermally conductive metal sheet 3. These features and connection structures are the same as those in existing packaging structures. The thermally conductive metal sheet 3 mentioned in this utility model is an indium sheet.

[0020] Unlike existing packaging structures, the packaging structure disclosed in this invention uses a metal layer to surround the heat-conducting metal sheet 3 on the non-functional surface 202 of the chip 2 and the inner surface of the heat sink 4. This avoids the problem of flux volatilization during high-temperature reflow forming a mixture with the molten heat-conducting metal sheet 3, which, under vacuum conditions, causes a large amount of flux gas to be carried out, resulting in low coverage of the heat-conducting metal sheet 3 on the gold-backed surface of the chip 2 and a large number of voids. This greatly improves the heat dissipation effect of the packaging structure.

[0021] Specifically, a first metal layer 6 is provided on the non-functional surface 202 of chip 2. The first metal layer 6 includes a first sidewall metal layer 601 surrounding the non-functional surface 202, which surrounds the heat-conducting metal sheet 3. The provision of the first metal layer 6 on the non-functional surface 202 of chip 2 is a prior art technique, meaning that the first metal layer 6 is directly electroplated on the non-functional surface 202 of the wafer, and after dicing, several chips 2 are formed. This results in each chip 2 having a first sidewall metal layer 601 surrounding its non-functional surface 202. To achieve faster heat conduction, a bottom metal layer 602 is also formed during the electroplating of the first metal layer 6. The bottom metal layer 602 is connected to the first sidewall metal layer 601, forming a first metal layer 6 with metal on all five sides. The size of the first metal layer 6 can be the same as the size of the chip 2.

[0022] A second metal layer 7, also formed by electroplating, is provided on the inner surface of the heat sink 4. The second metal layer 7 includes a second sidewall metal layer 701 and a top metal layer 702 connected to each other. The second sidewall metal layer 701 surrounds the heat-conducting metal sheet 3. The second metal layer 7 covers the surface of the first metal layer 6 on which the heat-conducting metal sheet 3 is mounted, and the first metal layer 6 and the second metal layer 7 completely surround the heat-conducting metal sheet 3. After reflow at high temperature, the heat-conducting metal sheet 3 is bonded to the first metal layer 6 and the second metal layer 7. The reflow temperature is typically 170℃-180℃, which is higher than the melting point of the heat-conducting metal sheet 3 (indium sheet) at 156.61℃.

[0023] The first metal layer 6 and the second metal layer 7 are made of gold and have a thickness of 200-500μm.

[0024] A plurality of first micropores 603 are provided in the first sidewall metal layer 601. A plurality of second micropores 703 are provided in the second sidewall metal layer 701. The diameter of the first micropores 603 and the second micropores 703 is 50±5μm.

[0025] In this invention, the thermally conductive metal sheet 3 is completely surrounded by the first metal layer 6 and the second metal layer 7, and also includes the first micro-pore 603 and the second micro-pore 703. This effectively prevents the formation of a mixture between the flux vapors and the molten thermally conductive metal sheet 3 during the high-temperature reflow process. Furthermore, the thermally conductive metal sheet 3, even under vacuum conditions during reflow, will not be carried away by the flux vapors. Therefore, using the technical solution of this invention avoids the problem of insufficient coverage of the thermally conductive metal sheet 3 on the surface of the back-gold chip 2, resulting in numerous voids, and greatly improves the heat dissipation effect of the packaging structure.

[0026] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A high-heat-dissipation packaging structure, comprising a substrate, a chip, a thermally conductive metal sheet, and a heat sink, wherein the functional surface of the chip is flip-chip mounted on the surface of the substrate, the thermally conductive metal sheet is disposed above the chip, and the heat sink is mounted on the surface of the substrate, covering the chip and the thermally conductive metal sheet, characterized in that, The non-functional surface of the chip is provided with a first metal layer, the first metal layer including a first sidewall metal layer surrounding the chip, the first sidewall metal layer surrounding the heat-conducting metal sheet; the inner surface of the heat sink is provided with a second metal layer, the second metal layer covering the surface of the first metal layer on which the heat-conducting metal sheet is attached.

2. The high heat dissipation packaging structure according to claim 1, characterized in that, The first sidewall metal layer is provided with a plurality of first micro pores.

3. The high heat dissipation packaging structure according to claim 2, characterized in that, The first metal layer also includes a bottom metal layer, which is connected to the first sidewall metal layer.

4. The high heat dissipation packaging structure according to claim 2 or 3, characterized in that, The second metal layer includes a second sidewall metal layer and a top metal layer connected together, with the second sidewall metal layer surrounding the heat-conducting metal sheet.

5. The high heat dissipation packaging structure according to claim 4, characterized in that, The second sidewall metal layer is provided with multiple second micro-pores.

6. The high heat dissipation packaging structure according to claim 5, characterized in that, The diameters of the first and second micropores are 50±5μm.

7. The high heat dissipation packaging structure according to claim 6, characterized in that, The first and second metal layers are made of gold and have a thickness of 200-500 μm.

8. The high heat dissipation packaging structure according to claim 7, characterized in that, The thermally conductive metal sheet is an indium sheet.

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