Liquid cooling plate for welding

Abstract

The invention provides a liquid cooling plate for welding. The liquid cooling plate for welding comprises a first substrate and a second substrate, the bonding pad is arranged on the upper surface of the first substrate, and the bonding pad can be connected with a chip through a welding material; a nickel layer, wherein the nickel layer covers the bonding pad; the solder resist ink layer is arranged on the upper surface of the first substrate and surrounds the edge of the bonding pad, 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; and the plurality of pin fins are arranged on the lower surface of the first substrate at intervals. According to the liquid cooling plate for welding, welding materials can be prevented from flowing out of the bonding pad, and thermal resistance is reduced.

Description

Technical Field

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

[0002] Liquid cooling plates have been widely used for chips. In order to achieve better contact with the pads of the liquid cooling plate, a nickel layer is plated on the pads.

[0003] However, the nickel layer has good wettability with tin-containing soldering materials. During the soldering process of the chip, the soldering material flows out of the pad, resulting in less soldering material at the bottom of the chip, resulting in poor soldering between the chip and the pad, high thermal resistance, and easy wire drawing at the edge of the pad. 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, which can reduce the welding material flowing out of the welding pad and reduce the thermal resistance.

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

[0006] a first substrate;

[0007] A pad, the pad being arranged on the upper surface of the first substrate, the pad being capable of connecting the chip through a welding material;

[0008] a nickel layer, wherein the nickel layer covers the pad;

[0009] A solder resist ink layer, the solder resist ink layer is disposed on the upper surface of the first substrate and is disposed around the edge of the pad, and the wettability of the solder resist ink layer to the welding material is lower than the wettability of the nickel layer to the welding material;

[0010] A plurality of pin fins are disposed on the lower surface of the first substrate at intervals.

[0011] Furthermore, the liquid cooling plate further comprises:

[0012] A groove is arranged on the upper surface of the first substrate and is arranged around the pad, and the solder resist ink layer is filled into the groove.

[0013] Furthermore, the first substrate comprises:

[0014] matrix;

[0015] A first platform, wherein the first platform protrudes upward from the substrate, the pad, the groove and the solder resist ink layer are all arranged on the first platform, and a side wall of the first platform is formed with an inclined surface which is not covered with the nickel layer and is inclined outward.

[0016] Furthermore, the liquid cooling plate further comprises:

[0017] A plurality of ejector pins are disposed on the pad and protrude upward from the pad, and the chip can be supported by the plurality of ejector pins.

[0018] Furthermore, the solder resist ink layer includes an inner circle ink layer and an outer circle ink layer that are adjacently arranged, the inner circle ink layer is close to the pad, the outer circle ink layer is far away from the pad, and the height of the outer circle ink layer relative to the first substrate is higher than the height of the inner circle ink layer.

[0019] Furthermore, the upper surface of the inner circle ink layer is not higher than the top surface of the pad, and the upper surface of the outer circle ink layer is higher than the top surface of the pad and lower than the top of the ejector pin.

[0020] Furthermore, the solder resist ink layer is a photosensitive ink layer.

[0021] Furthermore, the solder resist ink is formed by printing.

[0022] Furthermore, the printing is piezoelectric inkjet printing.

[0023] Furthermore, the liquid cooling plate further comprises:

[0024] The second substrate covers the lower surface of the first substrate, and a groove is formed on the upper surface of the second substrate. The groove accommodates all the pin fins, and the groove can accommodate cooling liquid.

[0025] Due to the above technical solution, the present invention has the following beneficial effects:

[0026] According to the liquid cooling plate for welding of the present invention, a pad is arranged on the first substrate, and a nickel layer is covered on the pad to achieve better welding with the chip. The solder resist ink layer arranged around the edge of the pad can have poor wettability with the welding material, can prevent the welding material from flowing out of the pad, and concentrate the welding material on the pad, so that there is enough welding material between the chip and the pad, and better welding between the chip and the pad is achieved, thermal resistance is reduced, and edge drawing is avoided. A plurality of pin fins are arranged on the lower surface of the first substrate, so that the contact area with the coolant can be increased, and the heat dissipation efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 is a structural diagram of a liquid cooling plate according to an embodiment of the present invention;

[0029] Figure 2 yes Figure 1 The structural diagram of the part in;

[0030] Figure 3 yes Figure 2 An enlarged view of area A in FIG.

[0031] Figure 4 is a structural diagram of a pad and a groove according to an embodiment of the present invention;

[0032] Figure 5 is a structural diagram of a pad, a groove and a solder resist ink layer according to an embodiment of the present invention;

[0033] Figure 6 is a structural diagram of a pad and a solder resist ink layer according to an embodiment of the present invention;

[0034] Figure 7 yes Figure 6 A partial stereogram of a pad and a solder resist ink layer of an embodiment;

[0035] Figure 8 is a structural diagram of a first substrate and pin fins according to an embodiment of the present invention;

[0036] Fig. 9 is a structural diagram of a second substrate according to an embodiment of the present invention.

[0037] Reference numerals:

[0038] 11. first substrate; 111. base; 112. first platform; 12. pad; 13. solder resist ink layer; 131. inner circle ink layer; 132. outer circle ink layer; 14. ejector pin; 15. pin fin; 16. groove;

[0039] 20. Second substrate; 21. Groove. DETAILED DESCRIPTION

[0040] 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.

[0041] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings 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.

[0042] Next, a liquid cooling plate for welding according to an embodiment of the present invention is described.

[0043] like Figures 1 to 9 As shown, the liquid cooling plate for welding according to the embodiment of the present invention includes a first substrate 11 , a solder pad 12 , a nickel layer, a solder resist ink layer 13 , a plurality of pin fins 15 and a second substrate 20 .

[0044] First, the first substrate 11, the pad 12 and the nickel layer are described. The pad 12 is disposed on the upper surface of the first substrate 11, and the pad 12 can be connected to the chip through a soldering material. The nickel layer covers the pad 12. The soldering material can be a tin-containing material for soldering.

[0045] like Figure 1 and Figure 2 As shown, six pads 12 are arranged on the upper surface of the first substrate 11, so that six chips can be connected by welding materials. The nickel layer covers the pads 12, and the pads 12 can be well welded with the chips through the nickel layer to reduce thermal resistance.

[0046] Next, the solder resist ink layer 13 is described. The solder resist ink layer 13 is disposed on the upper surface of the first substrate 11 and around the edge of the pad 12. The wettability of the solder resist ink layer 13 to the solder material is lower than that of the nickel layer to the solder material.

[0047] 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.

[0048] Finally, the plurality of pin fins 15 will be described. The plurality of pin fins 15 are provided on the lower surface of the first substrate 11 at intervals.

[0049] like Figure 8 As shown, a plurality of pin fins 15 are provided on the lower surface of the first substrate 11. This can increase the contact area between the liquid cooling plate and the cooling liquid, thereby improving the heat dissipation efficiency.

[0050] In the above liquid cooling plate for welding, a soldering pad 12 is arranged on the first substrate 11, and a nickel layer is covered on the soldering pad 12 to achieve better welding with the chip. The solder resist ink layer 13 arranged around the edge of the soldering pad 12 can have poor wettability with the welding material, can prevent the welding material from flowing out of the soldering pad 12, and concentrate the welding material on the soldering pad 12, so that there is enough welding material between the chip and the soldering pad 12, to achieve better welding between the chip and the soldering pad 12, reduce thermal resistance, and avoid edge drawing. A plurality of pin fins 15 are arranged on the lower surface of the first substrate 11, so as to increase the contact area with the coolant and improve the heat dissipation efficiency.

[0051] In some embodiments of the present invention, the liquid cooling plate further includes a groove 16 , which is disposed on the upper surface of the first substrate 11 and surrounds the pad 12 , and the solder resist ink layer 13 is filled into the groove 16 .

[0052] like Figure 4 and Figure 5 As shown, a circle of grooves 16 are formed at the edge of the pad 12, and the solder resist ink layer 13 is filled (buried) in the grooves 16. The grooves 16 can realize that the solder resist ink layer 13 has a higher aspect ratio, and the upper surface of the solder resist ink layer 13 is flat, which better prevents the flow of solder material and prevents the solder material from flowing out of the pad 12.

[0053] Furthermore, the first substrate 11 includes a base 111 and a first platform 112. The first platform 112 protrudes upward from the base 111, and the pad 12, the groove 16 and the solder resist ink layer 13 are all arranged on the first platform 112. The sidewall of the first platform 112 is formed with an inclined surface not covered with a nickel layer and inclined outward.

[0054] The inclined surface can be formed by the following method: a nickel layer is formed by spraying or electroplating the entire surface of the first substrate 11, the first platform 112 and the pad 12, and then the edge of the first platform 112 is cut to form an inclined surface without the nickel layer attached (covered).

[0055] like Figure 2 and Figure 3As shown, since the inclined surface is not covered with a nickel layer, the wettability with the solder material is poor, which will limit / block the solder material from flowing toward the inclined surface. Therefore, when the chip contacts the pad 12 through the solder material, the solder material is concentrated at the bottom of the chip, increasing the stability of the connection between the chip and the pad 12 and reducing thermal resistance.

[0056] In some embodiments of the present invention, the liquid cooling plate further includes a plurality of ejector pins 14. The plurality of ejector pins 14 are disposed on the pad 12 and protrude upward from the pad 12, and the chip can be supported by the plurality of ejector pins 14.

[0057] like Figure 2 As shown, four ejector pins 14 are arranged on the pad 12. The plurality of ejector pins 14 can support the chip so that the chip is at a distance from the pad 12, and the distance can accommodate the soldering material, increase the amount of soldering material between the chip and the pad 12, and further reduce the thermal resistance between the chip and the pad 12.

[0058] Furthermore, the solder resist ink layer 13 includes an inner circle ink layer 131 and an outer circle ink layer 132 which are adjacently arranged, the inner circle ink layer 131 is close to the pad 12, the outer circle ink layer 132 is far away from the pad 12, and the height of the outer circle ink layer 132 relative to the first substrate 11 is higher than the height of the inner circle ink layer 131.

[0059] like Figure 6 and Figure 7 As shown, an inner circle ink layer 131 and an outer circle ink layer 132 are sequentially arranged around the pad 12. The height of the outer circle ink layer 132 relative to the first substrate 11 is higher than the height of the inner circle ink layer 131. Thus, a height difference of the ink can be formed, and the inner circle ink layer 131 prevents the flow of the soldering material by virtue of the poor wettability with the soldering material. Even if the soldering material overflows to the outer circle ink layer 132, due to the height difference, the soldering material can flow back to the inner circle ink layer 131 and the pad 12. Moreover, even if the inner circle ink layer 131 has an abnormality (partial loss, pinholes, etc.), the outer circle ink layer 132 can also prevent the soldering material from flowing out. Thus, the stability of preventing the soldering material from flowing out can be increased.

[0060] Furthermore, the upper surface of the inner circle ink layer 131 is not higher than the top surface of the pad 12 , and the upper surface of the outer circle ink layer 132 is higher than the top surface of the pad 12 and lower than the top of the ejector pin 14 .

[0061] The upper surface of the inner circle ink layer 131 is not higher than the top surface of the pad 12, which can prevent the inner circle ink layer 131 from overflowing onto the pad 12, thereby contaminating the pad 12. The upper surface of the outer circle ink layer 132 is higher than the top surface of the pad 12 and lower than the top of the ejector pin 14, which can form a dam, which can significantly prevent the soldering material from overflowing, and even if the outer circle ink layer 132 overflows, it overflows onto the inner circle ink layer 131, thereby avoiding contamination of the pad 12. In addition, the outer circle ink layer 132 can avoid interference with the chip.

[0062] In some embodiments of the present invention, the solder resist ink layer 13 is a photosensitive ink layer.

[0063] 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.

[0064] Optionally, the photosensitive ink is an ultraviolet light curing ink.

[0065] Ultraviolet curing ink (UV ink) has a short curing time, some of which can be cured in 1 minute, which can improve efficiency.

[0066] Furthermore, the solder resist ink is formed by printing.

[0067] 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.

[0068] Moreover, the printing efficiency is high, which can improve work efficiency.

[0069] Further, the printing is piezoelectric inkjet printing.

[0070] 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.

[0071] In some embodiments of the present invention, the liquid cooling plate further comprises a second substrate 20. The second substrate 20 covers the lower surface of the first substrate 11, and a groove 21 is formed on the upper surface of the second substrate 20, and the groove 21 accommodates all the pin fins 15, and the groove 21 can accommodate the cooling liquid.

[0072] like Figure 1 and Fig. 9As shown, the groove 21 on the second substrate 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.

[0073] 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 liquid cooling plate for welding, characterized in that: The liquid cooling plate comprises: a first substrate; A pad, the pad being arranged on the upper surface of the first substrate, the pad being capable of connecting the chip through a welding material; a nickel layer, wherein the nickel layer covers the pad; A solder resist ink layer, the solder resist ink layer is disposed on the upper surface of the first substrate and is disposed around the edge of the pad, and the wettability of the solder resist ink layer to the welding material is lower than the wettability of the nickel layer to the welding material; A plurality of pin fins are disposed on the lower surface of the first substrate at intervals.

2. The liquid cooling plate for welding according to claim 1, characterized in that: The liquid cooling plate also includes: A groove is arranged on the upper surface of the first substrate and is arranged around the pad, and the solder resist ink layer is filled into the groove.

3. The liquid cooling plate for welding according to claim 2, characterized in that: The first substrate comprises: matrix; A first platform, wherein the first platform protrudes upward from the substrate, the pad, the groove and the solder resist ink layer are all arranged on the first platform, and a side wall of the first platform is formed with an inclined surface which is not covered with the nickel layer and is inclined outward.

4. The liquid cooling plate for welding according to claim 1, characterized in that: The liquid cooling plate also includes: A plurality of ejector pins are disposed on the pad and protrude upward from the pad, and the chip can be supported by the plurality of ejector pins.

5. The liquid cooling plate for welding according to claim 4, characterized in that: The solder resist ink layer includes an inner circle ink layer and an outer circle ink layer that are adjacent to each other, the inner circle ink layer is close to the pad, the outer circle ink layer is far away from the pad, and the height of the outer circle ink layer relative to the first substrate is higher than the height of the inner circle ink layer.

6. The liquid cooling plate for welding according to claim 5, characterized in that: The upper surface of the inner circle ink layer is not higher than the top surface of the pad, and the upper surface of the outer circle ink layer is higher than the top surface of the pad and lower than the top of the ejector pin.

7. The liquid cooling plate for welding according to claim 1, characterized in that: The solder resist ink layer is a photosensitive ink layer.

8. The liquid cooling plate for welding according to claim 7, characterized in that: The solder resist ink is formed by printing.

9. The liquid cooling plate for welding according to claim 8, characterized in that: The printing is piezoelectric inkjet printing.

10. The liquid cooling plate for welding according to claim 1, characterized in that: The liquid cooling plate also includes: The second substrate covers the lower surface of the first substrate, and a groove is formed on the upper surface of the second substrate. The groove accommodates all the pin fins, and the groove can accommodate cooling liquid.

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