A method of manufacturing a water-cooled copper-based PCB board

Abstract

The present application belongs to the technical field of electronic manufacturing, and relates to a method for preparing a water-cooled copper-based PCB board, comprising the following steps: processing micro-channel grooves on two copper substrates respectively, and welding the two copper substrates together to make the micro-channel grooves of the two copper substrates be central mirror symmetry; processing through holes on the copper substrates, and filling the through holes with resin; placing PCB core boards on the front and back surfaces of the copper substrates respectively to obtain a PCB board; performing secondary drilling on the PCB board, and electroplating the through holes of the secondary drilling to obtain a water-cooled copper-based PCB board. The water-cooled copper-based PCB board prepared by the method can quickly conduct heat, is suitable for high-power and high-integration TR modules, and has the advantages of lightness, thinness, and fast heat conduction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic manufacturing, in particular to a method for preparing a water-cooled copper-based PCB plate. BACKGROUND

[0002] In order to achieve good heat dissipation of the PCB, a metalized through hole is usually punched on the PCB plate, and the heat generated by the device on the plate is conducted to the heat dissipation structure through the metalized through hole. This way has high thermal resistance and poor heat conduction efficiency, and is easy to cause heat accumulation of the device on the plate, resulting in that the device cannot work normally. On the other hand, in the TR application field, integration is increasingly integrated, and the TR module has high heat density. In order to achieve high integration, the TR chip can only be welded on the plate. The welding on the PCB has large thermal resistance of the metalized hole and poor heat dissipation effect. If the chip is welded on the structural member, the longitudinal thickness and the volume size of the TR module will be increased.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] The technical problem to be solved by the present application is that the existing TR module cannot simultaneously achieve high integration and high heat dissipation performance.

[0005] In order to solve the above technical problem, the present application realizes the following technical scheme:

[0006] The present application provides a method for preparing a water-cooled copper-based PCB plate, comprising the following steps: processing a first micro-channel groove on a first copper substrate, and processing a second micro-channel groove on a second copper substrate; setting a first interface at the end of the first micro-channel groove, and setting a second interface at the end of the second micro-channel groove; the first interface and the second interface are connected to an external liquid cooling system; the first copper substrate with the first micro-channel groove and the first interface is pressure-welded with the second copper substrate with the second micro-channel groove and the second interface to obtain a third copper substrate; in the third copper substrate, the first micro-channel groove and the second micro-channel groove are centrally and mirror-symmetrically arranged; processing a first through hole on the third copper substrate, and filling the first through hole with resin to obtain a fourth copper substrate with a resin hole; placing a first PCB core plate on the front surface of the fourth copper substrate, and placing a second PCB core plate on the back surface of the fourth copper substrate to obtain a PCB plate; processing a second through hole on the PCB plate corresponding to the resin hole, and electroplating the second through hole to obtain the water-cooled copper-based PCB plate; the second through hole penetrates the first PCB core plate, the resin hole and the second PCB core plate.

[0007] Further, the method for preparing a water-cooled copper-based PCB plate further comprises the following steps: processing a blind groove on the first PCB core plate; the depth of the blind groove is equal to the depth of the first PCB core plate.

[0008] Further, the processing technology of the blind groove is a depth control milling process.

[0009] Further, the thickness of the first copper substrate and the thickness of the second copper substrate are both 0.5 mm; the depth of the first micro-channel groove and the depth of the second micro-channel groove are both 0.2 mm; and the width of the first micro-channel groove and the width of the second micro-channel groove are both 0.1 mm to 0.5 mm.

[0010] Further, the processing technology of the first micro-channel groove and the processing technology of the second micro-channel groove are both a depth control milling process.

[0011] Further, the method for filling the first through hole with resin is to continuously fill the first through hole with epoxy resin or polyimide resin until the epoxy resin or the polyimide resin overflows the first through hole; and the height of the overflowing epoxy resin or the height of the overflowing polyimide resin is 0.1 mm.

[0012] Further, after the first through hole is filled with resin, the method further comprises the step of: polishing the overflowing epoxy resin or the overflowing polyimide resin flat with a depth control grinding wheel.

[0013] Further, after the fourth copper substrate with a resin hole is obtained, the method further comprises the step of: preheating the fourth copper substrate to 100 DEG C.

[0014] Further, the method for placing a first PCB core plate on the front surface of the fourth copper substrate is to press the first PCB core plate on the front surface of the fourth copper substrate at a temperature of 500 DEG C; and the method for placing a second PCB core plate on the back surface of the fourth copper substrate is to press the second PCB core plate on the back surface of the fourth copper substrate at a temperature of 500 DEG C.

[0015] Further, the electroplating comprises: chemical copper plating or electroplating copper.

[0016] Compared with the prior art, the present application has the following advantages and beneficial effects: a micro-channel groove is processed on a copper substrate through a depth control milling process, and two copper substrates are mirror-symmetrically pressed and welded together through welding technology to form a copper substrate with a micro-channel groove. Subsequently, through steps of depth control milling, resin filling, PCB pressing, drilling, electroplating, etc., a copper-based PCB with a water-cooled micro-channel is prepared. The water-cooled copper-based PCB can quickly conduct heat and is suitable for high-power and high-integration TR modules, and has the advantages of lightness, thinness and fast heat conduction. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0018] Figure 1 The flow chart of the method for preparing the water-cooled copper-based PCB provided by the embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the present application in combination with the embodiments and drawings, the illustrative embodiments of the present application and the description thereof are only used to explain the present application, and should not be considered as limiting the present application.

[0020] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be practiced without these specific details. In other embodiments, well-known structures, circuits, materials or processes are not specifically described in order to avoid obscuring the present application.

[0021] Throughout this specification, the recitation of "one embodiment", "an embodiment", "one example" or "an example" means that a particular feature, structure, characteristic, or property described in connection with the embodiment or example is included in at least one embodiment of the present application. Therefore, the phrases "one embodiment", "an embodiment", "one example" or "an example" appearing throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, characteristics, or properties can be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art should understand that the drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] In the description of the present application, the terms "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0023] Embodiment: A method for preparing a water-cooled copper-based PCB is proposed, comprisingFigure 1 The following steps are shown:

[0024] Step 1: Select two copper substrates of the same size, respectively marked as the first copper substrate and the second copper substrate.

[0025] The thickness of the first copper substrate and the second copper substrate is 0.5 mm.

[0026] Step 2: Process a first micro-channel groove on the first copper substrate, and process a second micro-channel groove on the second copper substrate.

[0027] The processing technology of the first micro-channel groove and the processing technology of the second micro-channel groove are both controlled depth milling processes. The depth of the first micro-channel groove and the depth of the second micro-channel groove are both 0.2 mm. The width of the first micro-channel groove and the width of the second micro-channel groove are both 0.1 mm to 0.5 mm. In addition, the first micro-channel groove and the second micro-channel groove are located inside the copper substrate and are centrally mirror-symmetric, forming a closed liquid cooling channel.

[0028] Step 3: Set a first interface at the end of the first micro-channel groove, and set a second interface at the end of the second micro-channel groove.

[0029] The first interface and the second interface are both connected to an external liquid cooling system. Liquid cooling liquid enters the water-cooled micro-channel inside the copper substrate through the interface, for quickly removing heat in the copper substrate.

[0030] Step 4: Press and weld the first copper substrate and the second copper substrate obtained in step 3 together to obtain a third copper substrate.

[0031] The first copper substrate and the second copper substrate are mirror-symmetrically pressed and welded together by welding technology to form a 1 mm thick copper substrate with a micro-channel groove. The welding layer is located between the two copper substrates to ensure the sealing of the micro-channel groove. The welding technology used is vacuum welding or hot press welding.

[0032] Step 5: Process a first through-hole on the third copper substrate, and fill the first through-hole with resin to obtain a fourth copper substrate with a resin hole.

[0033] A controlled depth milling cutter is used to process a first through-hole with a depth of 1 mm on the third copper substrate formed in step 4. The diameter of the first hole is determined according to the PCB design hole size. Epoxy resin or polyimide resin is continuously filled into the first through-hole until the epoxy resin or the polyimide resin overflows the first through-hole. The height of the overflowed epoxy resin or the height of the overflowed polyimide resin is 0.1 mm.

[0034] Step 6: Polish the overflowed resin flat.

[0035] The overflowed epoxy resin or overflowed polyimide resin is polished flat by using a depth control grinding wheel, so as to prepare for subsequent PCB drilling.

[0036] Step 7: Preheat the fourth copper substrate, then place the first PCB core plate on the front surface of the fourth copper substrate, and place the second PCB core plate on the back surface of the fourth copper substrate to obtain a PCB plate.

[0037] Specifically, the fourth copper substrate is preheated to 100°C, and the first PCB core plate is placed on the front surface of the fourth copper substrate, and the second PCB core plate is placed on the back surface of the fourth copper substrate. The first PCB core plate and the first PCB core plate are respectively tightly pressed on the front surface and the back surface of the fourth copper substrate using a temperature of 500°C. The first PCB core plate and the first PCB core plate are both pre-prepared with lines.

[0038] Step 8: Process a second through hole on the PCB plate at a position corresponding to the resin hole, and electroplate the second through hole.

[0039] The thick PCB plate obtained in step 7 is drilled again, the drilling direction starts from the front surface of the PCB, passes through the copper-based resin hole, and then reaches the back surface of the PCB, forming a second through hole. The second through hole is electroplated (chemical copper plating or electroplated copper), so that the front surface of the PCB, the resin hole and the back surface of the PCB are metallized, thereby electrically connecting the front and back PCBs.

[0040] Step 9: Process a blind slot on the first PCB core plate to obtain a water-cooled copper-based PCB plate.

[0041] The PCB plate obtained in step 8 is subjected to blind slot depth milling using a depth control milling machine, and the milling depth is controlled to the upper surface of the front copper substrate, thereby completing the blind slot processing and further optimizing the heat dissipation performance of the PCB.

[0042] In summary, the method for preparing a water-cooled copper-based PCB plate proposed in the embodiment is suitable for preparing a high-power and high-integration TR module, can realize rapid heat exchange, ensure the performance of the module, reduce the thickness of the TR module, and realize light and thin.

[0043] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a water-cooled copper-based PCB board, characterized in that, Includes the following steps: A first microchannel groove is fabricated on a first copper substrate, and a second microchannel groove is fabricated on a second copper substrate. A first interface is provided at the end of the first microchannel groove, and a second interface is provided at the end of the second microchannel groove; both the first interface and the second interface are connected to an external liquid cooling system. A first copper substrate having the first microchannel groove and the first interface is press-welded together with a second copper substrate having the second microchannel groove and the second interface to obtain a third copper substrate; in the third copper substrate, the first microchannel groove and the second microchannel groove are centrally mirror symmetrical. A first through hole is processed on the third copper substrate, and the first through hole is filled with resin to obtain a fourth copper substrate with resin holes. A first PCB core board is placed on the front side of the fourth copper substrate, and a second PCB core board is placed on the back side of the fourth copper substrate to obtain a PCB board. A second through hole is machined on the PCB board at the position corresponding to the resin hole, and the second through hole is electroplated to obtain the water-cooled copper-based PCB board; the second through hole penetrates the first PCB core board, the resin hole and the second PCB core board.

2. The method for preparing a water-cooled copper-based PCB board according to claim 1, characterized in that, It also includes the following steps: A blind slot is machined on the first PCB core board; the depth of the blind slot is equal to the depth of the first PCB core board.

3. The method for preparing a water-cooled copper-based PCB board according to claim 2, characterized in that, The processing technology for the blind groove is controlled depth milling.

4. A method for preparing a water-cooled copper-based PCB board according to any one of claims 1-3, characterized in that, The thickness of both the first copper substrate and the second copper substrate is 0.5 mm. The depth of the first microchannel groove and the depth of the second microchannel groove are both 0.2 mm, and the width of the first microchannel groove and the width of the second microchannel groove are both 0.1 mm to 0.5 mm.

5. A method for preparing a water-cooled copper-based PCB board according to any one of claims 1-3, characterized in that, The processing technology for both the first microchannel groove and the second microchannel groove is controlled depth milling.

6. A method for preparing a water-cooled copper-based PCB board according to any one of claims 1-3, characterized in that, The method of filling the first through hole with resin is as follows: the first through hole is continuously filled with epoxy resin or polyimide resin until the epoxy resin or polyimide resin overflows from the first through hole; the height of the overflowing epoxy resin or the height of the overflowing polyimide resin is 0.1 mm.

7. The method for preparing a water-cooled copper-based PCB board according to claim 6, characterized in that, After filling the first through hole with resin, the method further includes the following step: using a depth-controlled grinding wheel to smooth out the overflowing epoxy resin or overflowing polyimide resin.

8. A method for preparing a water-cooled copper-based PCB board according to any one of claims 1-3, characterized in that, After obtaining the fourth copper substrate with resin pores, the method further includes the following step: preheating the fourth copper substrate to 100°C.

9. A method for preparing a water-cooled copper-based PCB board according to any one of claims 1-3, characterized in that, The method of placing the first PCB core board on the front side of the fourth copper substrate is as follows: pressing the first PCB core board onto the front side of the fourth copper substrate at a temperature of 500°C. The method for placing the second PCB core board on the back side of the fourth copper substrate is as follows: the second PCB core board is pressed onto the back side of the fourth copper substrate at a temperature of 500°C.

10. A method for preparing a water-cooled copper-based PCB board according to any one of claims 1-3, characterized in that, The electroplating includes: chemical copper plating or electroplating of copper.

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