Liquid cooling plate for welding and manufacturing method

Abstract

The invention provides a liquid cooling plate for welding and a manufacturing method. The manufacturing method comprises the steps that S1, a substrate is obtained; s2, cutting the upper surface of the substrate to form a protruding bonding pad in a first predetermined area of the substrate, forming a base body in a non-bonding-pad area of the substrate, and connecting the bonding pad with a chip through a welding material; s3, electroplating or spraying the substrate to form a nickel layer; and S4, predetermined ink is printed on the upper surface of the substrate and around the edge of the bonding pad to form a solder resist ink layer, and the wettability of the solder resist ink layer and the welding material is lower than the wettability of the nickel layer and the welding material. According to the manufacturing method of the liquid cooling plate for welding, the situation that welding materials flow out of the bonding pad can be reduced, and thermal resistance is reduced.

Description

Technical Field

[0001] The invention relates to the field of chip radiators, and in particular to a liquid cooling plate for welding and a manufacturing method thereof. Background Art

[0002] Existing chips are usually cooled by liquid cooling plates to maintain their stable operation. In order to better weld the chip to the liquid cooling plate, a nickel layer is formed on the pad of the liquid cooling plate.

[0003] However, the soldering material (tin-containing material) can easily flow out of the nickel layer, resulting in insufficient soldering material between the chip and the pad, causing excessive thermal resistance. Moreover, the soldering material flows to the non-pad area of ​​the liquid cooling plate, which can easily cause contamination. Summary of the invention

[0004] In view of the above problems in the prior art, an object of the present invention is to provide a liquid cooling plate for welding and a manufacturing method thereof, which can reduce the flow of welding material outside the welding pad and reduce the thermal resistance after connection with the chip.

[0005] In order to solve the above problems, the present invention provides a method for manufacturing a liquid cooling plate for welding, the manufacturing method comprising:

[0006] Step S1, obtaining a substrate;

[0007] Step S2, cutting the upper surface of the substrate to form a protruding pad in a first predetermined area of ​​the substrate, and the non-pad area of ​​the substrate is formed as a matrix, and the pad is used to connect the chip through a welding material;

[0008] Step S3, electroplating or spraying the substrate to form a nickel layer;

[0009] Step S4, printing a predetermined ink on the upper surface of the substrate and around the edge of the pad to form a solder resist ink layer, wherein the wettability of the solder resist ink layer to the solder material is lower than the wettability of the nickel layer to the solder material.

[0010] Furthermore, between step S2 and step S3, the manufacturing method further includes:

[0011] Step S5, cutting the substrate to form a platform protruding from a second predetermined area on the upper surface of the substrate, and the pad is located on the platform;

[0012] Between step S3 and step S4, the manufacturing method further includes:

[0013] Step S6, cutting the side of the platform so that the side of the platform forms a bevel;

[0014] In the step S4, the predetermined ink is printed on the upper surface of the platform.

[0015] Furthermore, the inclined plane forms an angle of 45 degrees with the horizontal plane.

[0016] Furthermore, between step S2 and step S3, the manufacturing method further includes:

[0017] Step S7, cutting and pinning the pad to form a plurality of protruding ejector pins on the pad, wherein the ejector pins can support the chip.

[0018] Furthermore, the printing is piezoelectric inkjet printing.

[0019] Furthermore, the predetermined ink is ultraviolet light sensitive ink, and the ultraviolet light sensitive ink is ultraviolet light cured to form a solder resist ink layer.

[0020] Furthermore, the step S4 comprises:

[0021] Step S41, printing the predetermined ink of a first width around the edge of the pad;

[0022] Step S42, performing a first curing to form a first ink layer, wherein the upper surface of the first ink layer is lower than the top surface of the pad;

[0023] Step S43, printing the predetermined ink with a second width on the first ink layer and close to the outer edge of the first ink layer, wherein the second width is smaller than the first width;

[0024] Step S44, performing a second curing to form a second ink layer on the upper surface of the first ink layer, the second ink layer is a predetermined distance away from the edge of the pad, and the upper surface of the second ink layer is higher than the top surface of the pad and lower than or equal to the top of the ejector pin.

[0025] Furthermore, the step S1 comprises:

[0026] A substrate is obtained, and the substrate is cold forged so that a plurality of spaced-apart pin fins are formed in the middle of the lower surface of the substrate.

[0027] Furthermore, after step S4, the manufacturing method further includes:

[0028] Step S8, obtaining a bottom plate, cutting the bottom plate to form a groove in the middle of the bottom plate, connecting the upper surface of the bottom plate to the lower surface of the substrate, and all the pin fins are located in the groove.

[0029] The present invention also provides a welding liquid cooling plate, the welding liquid cooling plate comprising:

[0030] The welding liquid cooling plate is manufactured by any of the above-mentioned manufacturing methods for welding liquid cooling plates.

[0031] Due to the above technical solution, the present invention has the following beneficial effects:

[0032] According to the manufacturing method of the welding liquid cooling plate of the present invention, a substrate is obtained and cut to form a protruding pad. The substrate is electroplated or sprayed to form a nickel layer, and the nickel layer on the pad is connected to the chip through a welding material, so that the pad and the chip can be in good contact. A predetermined ink is printed on the upper surface of the substrate and around the edge of the pad to form a solder resist ink layer, which can prevent the welding material from flowing out of the pad, and concentrate the welding material on the pad to achieve better welding between the chip and the pad, reduce thermal resistance, and avoid edge wiredrawing. Moreover, the solder resist ink layer is formed by printing, which can avoid contamination of the nickel layer on the surface of the pad and improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments or prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 is a flow chart of a method for manufacturing a liquid cooling plate for welding according to an embodiment of the present invention;

[0035] Figure 2 is a structural diagram of a substrate according to an embodiment of the present invention;

[0036] Figure 3 yes Figure 2 A magnified image of area A;

[0037] Figure 4 yes Figure 2 A magnified image of the substrate without ink printed in area A;

[0038] Figure 5 is a schematic diagram of a pad and a solder resist ink layer according to an embodiment of the present invention;

[0039] Figure 6 yes Figure 5 A partial structural diagram of a pad and a solder resist ink layer of an embodiment;

[0040] Figure 7 yes Figure 2 A structural diagram of the lower plate surface of the substrate of the embodiment;

[0041] Figure 8 is a structural diagram of a base plate according to an embodiment of the present invention;

[0042] Fig. 9 is a structural diagram of the connection between a substrate and a bottom plate according to an embodiment of the present invention.

[0043] Reference numerals:

[0044] 11. substrate; 111. base; 112. platform; 12. pad; 13. solder resist ink layer; 131. first ink layer; 132. second ink layer; 14. ejector pin; 15. pin fin;

[0045] 20. Bottom plate; 21. Groove. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that the terms "first", "second", etc. of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0048] Next, a method for manufacturing a liquid cooling plate for welding according to an embodiment of the present invention is described.

[0049] like Figures 1 to 9 As shown, the manufacturing method of the welding liquid cooling plate according to the embodiment of the present invention includes:

[0050] Step S1, obtaining a substrate 11. The substrate 11 may be an aluminum plate, a copper plate, an aluminum alloy plate, or the like.

[0051] Step S2 , cutting the upper surface of the substrate 11 to form a protruding pad 12 in a first predetermined area of ​​the substrate 11 , and forming a base 111 in an area other than the pad 12 of the substrate 11 .

[0052] That is, the pad 12 and the base 111 are formed on the substrate 11. Figure 2 As shown, the pad 12 is higher than the substrate 111 , and the pad 12 is used to connect the chip.

[0053] Step S3, electroplating or spraying the substrate 11 to form a nickel layer.

[0054] The substrate 11 is electroplated or sprayed to form a nickel layer on the substrate 11. The nickel layer covers the pad 12, and the pad 12 can be well soldered with the chip through the nickel layer to reduce thermal resistance.

[0055] Compared with partial electroplating or spraying (which requires masking, etc.), the entire substrate 11 is electroplated or sprayed, which is easier to manufacture and has a simpler process.

[0056] Step S4, printing a predetermined ink on the upper surface of the substrate 111 and around the edge of the pad 12 to form a solder resist ink layer 13, wherein the wettability of the solder resist ink layer 13 to the solder material is lower than the wettability of the nickel layer to the solder material.

[0057] The soldering material flows from the pad 12 to the solder resist ink layer 13. The solder resist ink layer 13 has poor wettability with the soldering material, which can prevent the soldering material from flowing out of the pad 12 and concentrate the soldering material on the pad 12. Therefore, there is enough soldering material between the chip and the pad 12, achieving better soldering between the chip and the pad 12, reducing thermal resistance, and avoiding edge wire drawing.

[0058] Compared to forming the solder resist ink layer 13 by traditional printing (the screen contacts the nickel layer on the surface of the pad 12, which easily causes contamination of the nickel layer on the pad 12), forming the solder resist ink layer 13 by printing (the print head does not directly contact the nickel layer on the surface of the pad 12) can avoid contamination of the nickel layer on the surface of the pad 12.

[0059] The above method for making a liquid cooling plate for welding is to obtain a substrate 11 and cut the substrate 11 to form a protruding pad 12. The substrate 11 is electroplated or sprayed to form a nickel layer, and the nickel layer on the pad 12 is connected to the chip through a welding material, so that the pad 12 can be in good contact with the chip. A predetermined ink is printed on the upper surface of the substrate 111 and around the edge of the pad 12 to form a solder resist ink layer 13, which can prevent the welding material from flowing out of the pad 12, and concentrate the welding material on the pad 12 to achieve better welding between the chip and the pad 12, reduce thermal resistance, and avoid edge wiredrawing. Moreover, the formation of the solder resist ink layer 13 by printing can avoid contamination of the nickel layer on the surface of the pad 12 and improve operating efficiency.

[0060] In some embodiments of the present invention, between step S2 and step S3, the manufacturing method further includes: step S5, cutting the substrate 111 to form a platform 112 protruding from a second predetermined area on the upper surface of the substrate 111, and the pad 12 is located on the platform 112. Between step S3 and step S4, the manufacturing method further includes: step S6, cutting the side of the platform 112 to form an inclined surface on the side of the platform 112. In step S4, a predetermined ink is printed on the upper surface of the platform 112.

[0061] like Figure 2 , Figure 3 and Figure 4 As shown, a platform 112 is first formed below the pad 12, and the substrate 11 is electroplated or sprayed to form a nickel layer, and then the side of the platform 112 is cut to form a slope (such as Figure 4 Then, a solder resist ink layer (such as Figure 3 shown).

[0062] Since the bevel is not covered with a nickel layer and is relatively rough (cutting after the nickel layer is formed will remove the nickel layer on the bevel), the wettability with the solder material is poor, which will limit / block the solder material from flowing toward the bevel. Therefore, during the process of the chip contacting the pad 12 through the solder material, even if the solder material overflows outside the solder resist ink layer 13, the bevel will reduce the further flow of the solder material, causing the solder material to retreat to the pad 12 (the blocking force of the bevel is greater than the force of the solder material flowing outward, and the solder material retreats due to its own tension), thereby increasing the stability of the connection between the chip and the pad 12 and reducing thermal resistance.

[0063] Furthermore, the inclined plane forms an angle of 45 degrees with the horizontal plane.

[0064] This angle can better prevent the flow of welding materials and has low processing costs.

[0065] In some embodiments of the present invention, between step S2 and step S3, the manufacturing method further includes: step S7, cutting the pad 12 to form a plurality of protruding ejector pins 14 on the pad 12, and the ejector pins 14 can support the chip.

[0066] The pad 12 is cut to form a plurality of ejector pins 14 .

[0067] like Figure 2 As shown, four ejector pins 14 are formed on the pad, and the number of the ejector pins 14 is not limited. The chip can be supported by multiple ejector pins 14, so that there is a gap between the chip and the upper surface of the pad 12, and the gap can accommodate welding material, increase the amount of welding material between the chip and the pad 12, and further reduce the thermal resistance between the chip and the pad 12.

[0068] In some embodiments of the present invention, the printing is piezoelectric inkjet printing.

[0069] The solder resist ink layer 13 is formed by a piezoelectric inkjet printing method based on a piezoelectric valve, so as to achieve non-contact with the nickel layer on the surface of the pad 12, with a fast proofing speed, adjustable ink volume, and adjustable width.

[0070] Furthermore, the predetermined ink is ultraviolet light sensitive ink, and the ultraviolet light sensitive ink is ultraviolet light cured to form the solder resist ink layer 13 .

[0071] Photosensitive ink can be cured under light conditions to form a photosensitive ink layer. Compared with thermosetting ink (which needs to be heated in a furnace or oven for curing), photosensitive ink does not have a high-temperature drying process, which can prevent the nickel layer on the surface of the pad 12 from being contaminated and oxidized and prevent the pad 12 from deforming, thereby increasing the stability of the chip and pad 12 welding.

[0072] Moreover, the ultraviolet light-sensitive ink (UV ink) has a shorter ultraviolet light curing time, which can improve efficiency.

[0073] In some embodiments of the present invention, step S4 includes: step S41, printing a predetermined ink of a first width around the edge of the pad 12; step S42, performing a first curing to form a first ink layer 131, the upper surface of the first ink layer 131 is lower than the top surface of the pad 12; step S43, printing a predetermined ink of a second width on the first ink layer 131 and close to the outer edge of the first ink layer 131, the second width is less than the first width; step S44, performing a second curing to form a second ink layer 132 on the upper surface of the first ink layer 131, the second ink layer 132 is a predetermined distance from the edge of the pad 12, and the upper surface of the second ink layer 132 is higher than the top surface of the pad 12 and lower than or equal to the top of the ejector pin 14.

[0074] like Figure 5 and Figure 6 As shown, there is only the first ink layer 131 at a predetermined distance from the edge of the pad 12 , and outside the predetermined distance from the edge of the pad 12 and within the first width range, the first ink layer 131 and the second ink layer 132 overlap.

[0075] Printing the predetermined ink twice and curing it twice can reduce ink collapse and ink overflow, increase the flatness of the ink, and enable the predetermined ink to be fully cured.

[0076] Thus, an inner circle ink layer (an ink layer only in the area of ​​the first ink layer 131) and an outer circle ink layer (an ink layer formed by superimposing the first ink layer 131 and the second ink layer 132) are sequentially arranged around the pad 12. The height of the outer circle ink layer relative to the substrate 111 is higher than that of the inner circle ink layer. Thus, a height difference of the ink can be formed, and the inner circle ink layer prevents the flow of the welding material by virtue of the difference in wettability with the welding material. Even if the welding material overflows to the outer circle ink layer, the welding material can flow back to the inner circle ink layer and the pad 12 due to the height difference. Moreover, even if an abnormality occurs in the inner circle ink layer (partial loss, pinholes, etc.), the outer circle ink layer can prevent the welding material from flowing out. Thus, the stability of preventing the welding material from flowing out can be increased, and the welding material can be concentrated on the pad 12.

[0077] The upper surface of the inner circle ink layer is not higher than the top surface of the pad 12, which can prevent the inner circle ink layer from overflowing (uncured predetermined ink easily flows and overflows outside the printing area) onto the pad 12, thereby contaminating the pad 12, thereby preventing the flow of welding materials and improving the cleanliness of the pad. The upper surface of the outer circle ink layer is higher than the top surface of the pad 12 and lower than or equal to the top of the ejector pin 14, which can form a dam and significantly prevent the welding material from overflowing.

[0078] Furthermore, even if the outer ink layer overflows before solidification, the overflow will be onto the inner ink layer, thus avoiding contamination of the pad 12. In addition, the outer ink layer can avoid interference with the chip.

[0079] In some embodiments of the present invention, step S1 includes obtaining a substrate 11 and performing cold forging on the substrate 11 so that a plurality of spaced-apart pin fins 15 are formed in the middle of the lower surface of the substrate 11 .

[0080] like Figure 7 As shown, pin fins 15 are formed on the lower surface of the substrate 11, which can increase the heat dissipation area and improve the heat dissipation efficiency.

[0081] Furthermore, after step S4, the manufacturing method further includes:

[0082] Step S8 , obtaining the bottom plate 20 , cutting the bottom plate 20 to form a groove 21 in the middle of the bottom plate 20 , connecting the upper surface of the bottom plate 20 to the lower surface of the substrate 11 , and all the pin fins are located in the groove 21 .

[0083] like Figure 8 and Fig. 9 As shown, the groove 21 on the bottom plate 20 can accommodate the coolant, and the coolant contacts the pin fins 15, thereby increasing the contact area between the liquid cooling plate and the coolant and achieving better heat dissipation.

[0084] Next, a liquid cooling plate for welding according to an embodiment of the present invention will be described.

[0085] The welding liquid cooling plate is manufactured by any of the above-mentioned manufacturing methods of the welding liquid cooling plate.

[0086] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a liquid cooling plate for welding, characterized in that: The production method comprises: Step S1, obtaining a substrate; Step S2, cutting the upper surface of the substrate to form a protruding pad in a first predetermined area of ​​the substrate, and the non-pad area of ​​the substrate is formed as a matrix, and the pad is used to connect the chip through a welding material; Step S3, electroplating or spraying the substrate to form a nickel layer; Step S4, printing a predetermined ink on the upper surface of the substrate and around the edge of the pad to form a solder resist ink layer, wherein the wettability of the solder resist ink layer to the solder material is lower than the wettability of the nickel layer to the solder material.

2. The method for manufacturing a liquid cooling plate for welding according to claim 1, characterized in that: Between step S2 and step S3, the manufacturing method further includes: Step S5, cutting the substrate to form a platform protruding from a second predetermined area on the upper surface of the substrate, and the pad is located on the platform; Between step S3 and step S4, the manufacturing method further includes: Step S6, cutting the side of the platform so that the side of the platform forms a bevel; In the step S4, the predetermined ink is printed on the upper surface of the platform.

3. The method for manufacturing a liquid cooling plate for welding according to claim 2, characterized in that: The inclined plane forms an angle of 45 degrees with the horizontal plane.

4. The method for manufacturing a liquid cooling plate for welding according to claim 1, characterized in that: Between step S2 and step S3, the manufacturing method further includes: Step S7, cutting and pinning the pad to form a plurality of protruding ejector pins on the pad, wherein the ejector pins can support the chip.

5. The method for manufacturing a liquid cooling plate for welding according to claim 4, characterized in that: The printing is piezoelectric inkjet printing.

6. The method for manufacturing a liquid cooling plate for welding according to claim 5, characterized in that: The predetermined ink is ultraviolet light sensitive ink, and the ultraviolet light sensitive ink is ultraviolet light cured to form a solder resist ink layer.

7. The method for manufacturing a liquid cooling plate for welding according to claim 4, characterized in that: The step S4 comprises: Step S41, printing the predetermined ink of a first width around the edge of the pad; Step S42, performing a first curing to form a first ink layer, wherein the upper surface of the first ink layer is lower than the top surface of the pad; Step S43, printing the predetermined ink with a second width on the first ink layer and close to the outer edge of the first ink layer, wherein the second width is smaller than the first width; Step S44, performing a second curing to form a second ink layer on the upper surface of the first ink layer, the second ink layer is a predetermined distance away from the edge of the pad, and the upper surface of the second ink layer is higher than the top surface of the pad and lower than or equal to the top of the ejector pin.

8. The method for manufacturing a liquid cooling plate for welding according to claim 1, characterized in that: The step S1 comprises: A substrate is obtained, and the substrate is cold forged so that a plurality of spaced-apart pin fins are formed in the middle of the lower surface of the substrate.

9. The method for manufacturing a liquid cooling plate for welding according to claim 8, characterized in that: After step S4, the manufacturing method further includes: Step S8, obtaining a bottom plate, cutting the bottom plate to form a groove in the middle of the bottom plate, connecting the upper surface of the bottom plate to the lower surface of the substrate, and all the pin fins are located in the groove.

10. A liquid cooling plate for welding, characterized in that: The welding liquid cooling plate is manufactured by the manufacturing method of the welding liquid cooling plate according to any one of claims 1 to 9.

Images