A PCB assembly structure with liquid heat dissipation function and an assembly method thereof

Abstract

The present invention belongs to the field of semiconductor technology, and specifically relates to a PCB assembly structure with liquid heat dissipation function and an assembly method thereof, wherein the structure comprises a PCB board, the PCB board is provided with a groove, the groove is provided at the position corresponding to the liquid inlet and outlet, multiple layers of metal sheets are provided in and above the groove, chips are provided between adjacent metal sheets and on the upper surface of the top metal sheet, the bottom of the chip is interconnected with the pad on the surface of the PCB board or the upper surface of the lower chip by solder balls; a stand is provided at the end of the metal sheet, the stand is provided with a microchannel communicating with the metal sheet, and a liquid guide port is provided at the bottom of the stand and embedded in the PCB board. The present invention uses metal to make a bracket with a microchannel, uses the bracket to support the chip, and uses a multi-layer bracket to stack single-layer or multi-layer chips, which can better solve the heat dissipation problem of multi-layer chips.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors, and in particular relates to a PCB assembly structure with liquid heat dissipation function and an assembly method thereof. Background Art

[0002] Microwave millimeter wave radio frequency integrated circuit technology is the foundation of modern national defense weapons and equipment and the Internet industry. With the rapid rise of the "Internet +" economy such as smart communications, smart homes, smart logistics, and smart transportation, there is also a huge real demand and potential market for microwave millimeter wave radio frequency integrated circuits that undertake data access and transmission functions.

[0003] However, for high-frequency microsystems, the area of ​​the antenna array is getting smaller and smaller, and the distance between antennas must be kept within a certain range to enable the entire module to have excellent communication capabilities. However, for analog device chips such as RF chips, their area cannot be reduced exponentially like digital chips, so the ultra-high frequency RF microsystem will not have enough area to place PA / LNA at the same time, and the PA / LNA needs to be stacked or placed vertically.

[0004] Such a heat dissipation structure requires the use of more advanced liquid cooling or phase change cooling technology. Generally, the base of the RF module is made by metal processing, and a micro-channel is set inside the base. The module is fixed on the metal base by welding to complete the placement of the chip. However, with this stacking technology, the heat on the power chip needs to pass through several layers of medium to be transferred to the heat dissipation liquid, which is inefficient.

[0005] In order to further reduce the distance between the heat dissipation microchannel and the heat-generating chip, the current trend is to directly weld the microchannel heat sink under the chip, which can directly transfer the heat of the chip to the microchannel and increase the heat dissipation capacity of the system. However, for multi-layer modules, the upper chip still cannot contact the microchannel, or can only circulate liquid through the microchannel of the module. This heat dissipation efficiency is greatly different from the direct heat dissipation of the microchannel heat sink at the bottom, which will cause the operating temperature of the upper and lower chips to be inconsistent for a long time, resulting in reliability problems. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a PCB assembly structure with liquid heat dissipation function and an assembly method thereof, which can solve the heat dissipation problem of the upper chip of the multi-layer module.

[0007] According to the technical solution of the present invention, the PCB assembly structure with liquid heat dissipation function includes a PCB board, a groove is formed on the PCB board, the groove is formed corresponding to the position of the liquid inlet and outlet, multiple layers of metal sheets are arranged in and above the groove, chips are arranged between adjacent metal sheets and on the upper surface of the top metal sheet, the bottom of the chip is interconnected with the pad on the surface of the PCB board or the upper surface of the lower chip by solder balls; a stand is provided at the end of the metal sheet, the stand and the metal sheet are provided with microchannels communicating with each other, and the bottom of the stand is provided with a liquid guide port and embedded in the PCB board.

[0008] Furthermore, the metal sheets are arranged correspondingly up and down, and the ends of the multi-layer metal sheets share a stand to form a multi-layer metal frame structure, and the liquid guide port at the bottom of the stand is interconnected with the liquid inlet and outlet on the PCB board.

[0009] Furthermore, the metal sheets are arranged parallel to each other at an angle, and each layer of metal sheets and the vertical frames at the ends of the metal sheets form a single-layer metal frame structure; the liquid guide ports of the vertical frames at the ends of the metal sheets in the grooves are interconnected with the liquid inlet and outlet ports on the PCB board, and the vertical frames at the ends of the metal sheets above the grooves are inserted into the welding through holes on the PCB board.

[0010] Furthermore, the metal sheet includes a top cover metal and a base metal that are welded together, and microchannel grooves are provided on the lower surface of the top cover metal and the upper surface of the base metal.

[0011] Furthermore, it is characterized in that the metal sheet is in the shape of a long strip, a Y shape or a polygon.

[0012] Another aspect of the present invention further provides an assembly method of a PCB assembly structure with liquid heat dissipation function, comprising the following steps:

[0013] A1: A multi-layer metal frame with a microfluidic channel is manufactured, wherein the multi-layer metal frame comprises columns and multi-layer metal sheets installed between the columns, and a liquid guide port is provided at the bottom of the columns; a groove is manufactured on the PCB board, and the multi-layer metal frame is embedded in the PCB board, and the metal sheet of the bottom layer is welded in the groove, and the liquid guide port is interconnected with the liquid inlet and outlet of the PCB board;

[0014] A2: Solder the bottom chip on the top of the bottom metal sheet of the multi-layer metal frame to connect the bottom metal sheet to the bottom of the bottom chip, and at the same time, the bottom solder ball of the bottom chip is interconnected with the PCB pad;

[0015] A3: Solder the second layer chip on the surface of the second layer metal sheet, so that the bottom solder ball of the second layer chip is interconnected with the upper surface of the bottom chip, and the heating area of ​​the second layer chip is interconnected with the metal sheet; continue to operate the upper layers according to this method, and finally form a structure with liquid cooling and heat dissipation function.

[0016] A method for assembling a PCB assembly structure with liquid heat dissipation function comprises the following steps:

[0017] B1: A single-layer metal frame with a microfluidic channel is manufactured, wherein the single-layer metal frame includes columns and a metal sheet disposed between the tops of the columns; a groove and a welding through hole are manufactured on a PCB board, the single-layer metal frame is embedded in the PCB board, the metal sheet of the single-layer metal frame is welded in the groove, and the liquid guide port at the bottom of the column is interconnected with the liquid inlet and outlet of the PCB board;

[0018] B2: soldering the bottom chip on the top of the single-layer metal frame described in B1, so that the metal sheet of the single-layer metal frame is connected to the bottom of the bottom chip, and the bottom solder ball of the bottom chip is interconnected with the solder pad of the PCB board;

[0019] B3: A metal sheet with a microfluidic channel is welded to the single-layer metal frame welded with the bottom chip in B2, and the end of the metal sheet is welded to the column inserted into the welding through hole to form a second metal frame. At the same time, the bottom of the metal sheet is welded to the surface of the bottom chip;

[0020] B4: Weld the second layer chip on the surface of the second layer metal frame, so that the bottom solder ball of the second layer chip is interconnected with the upper surface of the bottom chip, and the heating area of ​​the second layer chip is interconnected with the metal sheet welded in B3. Continue to operate the upper layers according to this method to finally form a structure with liquid cooling and heat dissipation function.

[0021] The beneficial effect of the present invention is that a bracket with a microfluidic channel is made of metal, the chip is supported by the bracket, and a multi-layer bracket is used to stack single-layer or multi-layer chips, which can better solve the heat dissipation problem of multi-layer chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the multi-layer metal frame in the first embodiment.

[0023] Figure 2 This is a schematic diagram of the structure of a groove formed on a PCB board in Embodiment 1.

[0024] Figure 3 This is a schematic diagram of the structure in which a multi-layer metal frame is welded on a PCB board in Example 1.

[0025] Figure 4 This is a schematic diagram of the structure of welding the bottom chip in Example 1.

[0026] Figure 5 This is a schematic diagram of the structure of welding the second layer chip in Example 1.

[0027] Figure 6 This is a schematic diagram of the combined structure of the multi-layer metal frame and the chip in Example 1.

[0028] Figure 7 This is a schematic diagram of the structure of providing grooves and welding through holes on the PCB board in the second embodiment.

[0029] Figure 8 This is a schematic diagram of the structure in which a single-layer metal frame is welded on a PCB board in Embodiment 2.

[0030] Fig. 9 This is a schematic diagram of the structure of welding the bottom chip in the second embodiment.

[0031] Fig.10 This is a schematic diagram of the structure of welding the second layer of metal frame in Example 2.

[0032] Fig.11 This is a schematic diagram of the structure of welding the second layer chip in Example 2.

[0033] Fig.12 This is a schematic diagram of the combined structure of the multi-layer metal frame and the chip in Example 3.

[0034] Explanation of the reference numerals: 101 - PCB board, 102 - groove, 103 - liquid inlet and outlet, 104 - welding through hole, 105 - metal sheet, 106 - stand, 107 - microfluidic channel, 108 - liquid guide port, 109 - colloid, 110 - bottom chip, 111 - second chip. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0036] Embodiment 1

[0037] A PCB assembly structure with liquid heat dissipation function includes a PCB board 101, a groove 102 is formed on the PCB board, and the groove is formed at the position of a liquid inlet and outlet 103. A plurality of metal sheets 105 are provided in and above the groove 102. The metal sheets 105 are in a long strip shape. Chips are provided between adjacent metal sheets 105 and on the upper surface of the top metal sheet 105. The bottom of the chip is interconnected with a pad on the surface of the PCB board 101 or the upper surface of the lower chip by solder balls. A stand 106 is provided at the end of the metal sheet 105. A microchannel 107 communicating with the stand 106 and the metal sheet 105 is provided. A liquid guide port 108 is provided at the bottom of the stand 106 and is embedded in the PCB board 101. The metal sheets 105 are arranged correspondingly up and down, and the ends of the plurality of metal sheets 105 share a stand 106 to form a multi-layer metal frame structure. The liquid guide port 108 at the bottom of the stand 106 is interconnected with the liquid inlet and outlet 103 on the PCB board 101.

[0038] The assembly method of the PCB assembly structure with liquid heat dissipation function comprises the following steps:

[0039] A1: A multi-layer metal frame with a microfluidic channel 107 is manufactured. The multi-layer metal frame includes columns 106 and multi-layer metal sheets 105 installed between the columns 106. A liquid guide port 108 is provided at the bottom of the columns 105. A groove 102 is manufactured on the PCB board 101, and the multi-layer metal frame is embedded in the PCB board. The bottom metal sheet 105 is welded in the groove 102, and the liquid guide port 108 is interconnected with the liquid inlet and outlet 103 of the PCB board.

[0040] like Figure 1 As shown in the figure: microfluidic grooves are provided on the lower surface of the top cover metal and the upper surface of the base metal, and then the top cover metal and the base metal are welded together to form a metal sheet 105 with a microfluidic channel 107; the metal sheet 105 is welded to the stand 106 to form a microfluidic frame with multiple layers of metal sheets with microfluidic channels, wherein the stand 106 contains the same microfluidic channels 107 inside, and the welding process enables the microfluidic channels 107 of the metal sheet 105 and the microfluidic channels 107 of the stand 106 to form a liquid inlet and outlet loop, and the microfluidic channel outlet at the bottom of the stand 106 forms a liquid guide port 108;

[0041] like Figure 2 As shown: a groove 102 is made on a PCB board 101;

[0042] like Figure 3 As shown: the colloid 109 is filled in the groove 102, and the multi-layer metal frame is embedded in the PCB board 101, so that the liquid guide port 108 is interconnected with the liquid inlet and outlet port 103 of the PCB board;

[0043] A2: If Figure 4 As shown, the bottom chip 110 is welded on the top of the bottom metal sheet 105 of the multi-layer metal frame, so that the bottom metal sheet 105 is connected to the bottom of the bottom chip 110, and at the same time, the bottom solder ball (the solder ball is not drawn, the same below) of the bottom chip 110 is interconnected with the solder pad (the solder pad is not drawn, the same below) of the PCB board 101;

[0044] A3: Figure 5 As shown, the second layer chip 111 is welded on the surface of the second layer metal sheet 105 (the upper layer of the bottom metal sheet) of the multi-layer metal frame, so that the bottom solder ball of the second layer chip 111 is interconnected with the upper surface of the bottom chip 110, and the heating area (the dark area in the middle) of the second layer chip 111 is interconnected with the metal sheet 105. The combination state of the multi-layer metal frame and the two layers of chips is as shown in FIG. Figure 6 As shown; continue to operate the upper layers in this way, and finally form a structure with liquid cooling and heat dissipation function (the figure only shows the structure of two layers of metal frame and two layers of chip welded).

[0045] Embodiment 2

[0046] A PCB assembly structure with liquid heat dissipation function includes a PCB board 101, a groove 102 is formed on the PCB board, and the groove is formed corresponding to the position of a liquid inlet and outlet 103. A plurality of metal sheets 105 are provided in and above the groove 102. The metal sheets 105 are in the shape of long strips. Chips are provided between adjacent metal sheets 105 and on the upper surface of the top metal sheet 105. The bottom of the chip is interconnected with a pad on the surface of the PCB board 101 or the upper surface of a lower chip by means of solder balls. A stand 106 is provided at the end of the metal sheet 105. A microchannel 107 communicating with the stand 106 and the metal sheet 105 is provided. A liquid guide port 108 is provided at the bottom of the stand 106 and is embedded in the PCB board 101. The metal sheets 105 are arranged parallel to each other at an angle (vertical) up and down, and each layer of the metal sheets 105 and the stand 106 at its end form a single-layer metal frame structure; the stand liquid guide port 108 at the end of the metal sheet in the groove 102 is interconnected with the liquid inlet and outlet 103 on the PCB board, and the stand at the end of the metal sheet above the groove 102 is inserted into the welding through hole 104 on the PCB board.

[0047] The assembly method of the PCB assembly structure with liquid heat dissipation function comprises the following steps:

[0048] B1: A single-layer metal frame with a microfluidic channel 107 is manufactured, and the single-layer metal frame includes a column 106 and a metal sheet 105 disposed between the tops of the columns 106; a groove 102 and a welding through hole 104 are manufactured on a PCB board 101, and the single-layer metal frame is embedded in the PCB board 101, and the metal sheet 105 of the single-layer metal frame is welded in the groove 102, and the liquid guide port 108 at the bottom of the column is interconnected with the liquid inlet and outlet port 103 of the PCB board;

[0049] A single-layer metal frame with microchannels 107 is manufactured in the manner of Example 1;

[0050] like Figure 7 As shown, a groove 102 and a welding through hole 104 are made on a PCB board 101;

[0051] like Figure 8 As shown, the colloid 109 is filled in the groove 102, and the single-layer metal frame is embedded in the PCB board 101, so that the liquid guide port 108 of the frame is interconnected with the liquid inlet and outlet port 103 of the PCB board;

[0052] B2: If Fig. 9 As shown, the bottom chip 110 is welded on the top of the single-layer metal frame described in B1, so that the metal sheet 105 of the single-layer metal frame is connected to the bottom of the bottom chip 110, and the bottom solder ball of the bottom chip 110 is interconnected with the solder pad of the PCB board 101;

[0053] B3: If Fig.10As shown, the metal sheet 105 with the microchannel is further welded on the single-layer metal frame welded with the bottom chip 110 in B2, and the end of the metal sheet 105 is welded to the column 106 inserted into the welding through hole 104 to form a second layer of metal frame, and at the same time, the bottom of the metal sheet 105 is welded to the surface of the bottom chip 110;

[0054] B4: If Fig.11 As shown, the second layer chip 111 is welded on the surface of the second layer metal frame, so that the bottom solder ball of the second layer chip 111 is interconnected with the upper surface of the bottom layer chip 110, and the heating area of ​​the second layer chip 111 is interconnected with the metal sheet 105 welded in B3; continue to operate the upper layers according to this method, and finally form a structure with liquid cooling and heat dissipation function ( Fig.11 There are only two layers in the structure).

[0055] Embodiment 3

[0056] like Fig.12 As shown, the metal sheet 105 is in a Y-bar shape, and the chip can be placed in from three directions. Other structures and assembly methods are consistent with the embodiment.

[0057] It is conceivable that multiple sets of metal frame structures (multi-layer metal frames or superimposed single-layer metal frames) can be welded on a single PCB board, and the shape of the metal sheet can also be a polygon with microchannels or other shapes.

Claims

1. A method for assembling a PCB assembly structure with liquid heat dissipation function, characterized in that: The following steps are included: A1: A multi-layer metal frame with a microfluidic channel is manufactured, wherein the multi-layer metal frame comprises columns and multi-layer metal sheets installed between the columns, and a liquid guide port is provided at the bottom of the columns; a groove is manufactured on the PCB board, and the multi-layer metal frame is embedded in the PCB board, and the metal sheet of the bottom layer is welded in the groove, and the liquid guide port is interconnected with the liquid inlet and outlet of the PCB board; A2: Solder the bottom chip on the top of the bottom metal sheet of the multi-layer metal frame to connect the bottom metal sheet to the bottom of the bottom chip, and at the same time, the bottom solder ball of the bottom chip is interconnected with the PCB pad; A3: Solder the second layer chip on the surface of the second layer metal sheet, so that the bottom solder ball of the second layer chip is connected to the upper surface of the bottom chip, and the heating area of ​​the second layer chip is connected to the metal sheet; continue to operate the upper layers in this way, and finally form a structure with liquid cooling and heat dissipation function; The assembly method of a PCB assembly structure with a liquid heat dissipation function realizes the liquid heat dissipation function through the PCB assembly structure with a liquid heat dissipation function. The PCB assembly structure with a liquid heat dissipation function includes a PCB board, a groove is formed on the PCB board, the groove is formed corresponding to the position of the liquid inlet and outlet, multiple layers of metal sheets are arranged in and above the groove, chips are arranged between adjacent metal sheets and on the upper surface of the top metal sheet, the bottom of the chip is interconnected with the pad on the surface of the PCB board or the upper surface of the lower chip by solder balls; a stand is provided at the end of the metal sheet, the stand and the metal sheet are provided with a microchannel communicating with each other, and the bottom of the stand is provided with a liquid guide port and embedded in the PCB board; The metal sheets are arranged correspondingly up and down, and the ends of the multi-layer metal sheets share a stand to form a multi-layer metal frame structure, and the liquid guide port at the bottom of the stand is interconnected with the liquid inlet and outlet on the PCB board.

2. A method for assembling a PCB assembly structure with liquid heat dissipation function, characterized in that: The following steps are included: B1: A single-layer metal frame with a microfluidic channel is manufactured, wherein the single-layer metal frame includes columns and a metal sheet disposed between the tops of the columns; a groove and a welding through hole are manufactured on a PCB board, the single-layer metal frame is embedded in the PCB board, the metal sheet of the single-layer metal frame is welded in the groove, and the liquid guide port at the bottom of the column is interconnected with the liquid inlet and outlet of the PCB board; B2: soldering the bottom chip on the top of the single-layer metal frame described in B1, so that the metal sheet of the single-layer metal frame is connected to the bottom of the bottom chip, and the bottom solder ball of the bottom chip is interconnected with the solder pad of the PCB board; B3: A metal sheet with a microfluidic channel is welded to the single-layer metal frame welded with the bottom chip in B2, and the end of the metal sheet is welded to the column inserted into the welding through hole to form a second metal frame. At the same time, the bottom of the metal sheet is welded to the surface of the bottom chip; B4: Weld the second layer chip on the surface of the second layer metal frame, so that the bottom solder ball of the second layer chip is interconnected with the upper surface of the bottom layer chip, and the heating area of ​​the second layer chip is interconnected with the metal sheet welded in B3. Continue to operate the upper layers in this way, and finally form a structure with liquid cooling and heat dissipation function; The assembly method of a PCB assembly structure with a liquid heat dissipation function realizes the liquid heat dissipation function through the PCB assembly structure with a liquid heat dissipation function. The PCB assembly structure with a liquid heat dissipation function includes a PCB board, a groove is formed on the PCB board, the groove is formed corresponding to the position of the liquid inlet and outlet, multiple layers of metal sheets are arranged in and above the groove, chips are arranged between adjacent metal sheets and on the upper surface of the top metal sheet, the bottom of the chip is interconnected with the pad on the surface of the PCB board or the upper surface of the lower chip by solder balls; a stand is provided at the end of the metal sheet, the stand and the metal sheet are provided with a microchannel communicating with each other, and the bottom of the stand is provided with a liquid guide port and embedded in the PCB board; The metal sheets are arranged parallel to each other at an angle, and each layer of metal sheets and the stand at the end of the metal sheets form a single-layer metal frame structure; the stand at the end of the metal sheet in the groove is interconnected with the liquid inlet and outlet on the PCB board, and the stand at the end of the metal sheet above the groove is inserted into the welding through hole on the PCB board.

3. The method for assembling a PCB assembly structure with liquid heat dissipation function according to claim 1 or 2, characterized in that: The metal sheet comprises a top cover metal and a base metal which are welded together, and micro-channel grooves are arranged on the lower surface of the top cover metal and the upper surface of the base metal.

4. The method for assembling a PCB assembly structure with liquid heat dissipation function as claimed in claim 3, characterized in that: The metal sheet is in the shape of a long strip, a Y shape or a polygon.

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