Cooling disc and manufacturing method thereof

Abstract

The invention discloses a cooling disc and a manufacturing method thereof, and relates to the technical field of heat dissipation, the manufacturing method of the cooling disc comprises the following steps: nickel plating treatment: performing nickel plating treatment on a first welding surface of a supporting plate to form a nickel plating layer; assembling: arranging a welding flux on the nickel plating layer or the second welding surface of the heat conduction base, and then tightly pressing and fixing the welding flux on the heat conduction base and the supporting plate to finish assembling; vacuum brazing is conducted, specifically, the heat conduction base and the supporting plate which are assembled are placed into vacuum brazing equipment to be subjected to brazing treatment; in the brazing process, the welding flux infiltrates the nickel plating layer and the second welding surface after being melted, and a welding brazing layer is formed after cooling; the welding brazing layer is directly connected with the nickel plating layer and the second welding face. The coating has the advantages of long-acting stability and excellent heat conduction performance.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation, and in particular to a cooling plate and a manufacturing method thereof. Background Art

[0002] In semiconductor manufacturing, wafers undergo high-temperature processing and need to be transferred to a cooling chamber for cooling. Currently, the industry generally uses cooling plates with water channels to rapidly cool semiconductor wafers. These plates typically utilize a multi-layer composite structure: an inner layer constructed of a high-thermal-conductivity material to optimize heat transfer, while an outer layer is constructed of a mechanically strong material to ensure structural stability. However, practice has shown that these composite cooling plates are prone to thermal conductivity degradation during use, resulting in reduced heat dissipation uniformity across the wafers and impacting product yield.

[0003] In response to the above technical bottlenecks, developing a cooling disk with long-term stability and excellent thermal conductivity has become a key technical issue that needs to be urgently solved in this field. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides a cooling plate and a manufacturing method thereof, which have the advantages of long-term stability and excellent heat conduction performance.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions in the first aspect:

[0006] A method for manufacturing a cooling disk, which is used for semiconductors, comprises: nickel plating, wherein a first welding surface of a support plate is nickel-plated to form a nickel-plated layer; assembly, wherein solder is laid on the nickel-plated layer or on a second welding surface of a thermally conductive base, and then the thermally conductive base and the support plate are pressed against the solder and fixed to complete the assembly; vacuum brazing, wherein the assembled thermally conductive base and the support plate are placed in a vacuum brazing device for brazing; during the brazing process, the solder melts and infiltrates the nickel-plated layer and the second welding surface, and forms a brazing layer after cooling; and the brazing layer is directly connected to the nickel-plated layer and the second welding surface, respectively.

[0007] Optionally, before the vacuum brazing, the method further includes: processing welding parts, processing concave and convex limiting parts that can fit with each other in a clearance on the second welding surface of the thermally conductive base and the first welding surface of the support plate respectively; accordingly, the nickel plating layer formed in the nickel plating treatment covers the first welding surface and the surface of the concave and convex limiting parts on the first welding surface; the area where the solder is arranged in the assembly is a predetermined area on the nickel plating layer or on the second welding surface, and the predetermined area is each plane parallel to the second welding surface or the first welding surface; after the assembly is completed, the concave and convex limiting parts on the thermally conductive base and the support plate are in a clearance fit state; during the brazing process, part of the liquid solder after the solder melts fills the gap between the concave and convex limiting parts under capillary action; the welding fiber layer formed after the solder cools includes the part filling the gap between the concave and convex limiting parts.

[0008] Optionally, in the processing of the welded part, the concave and convex limiting portion includes a concave portion and a convex portion; the concave portion is arranged on one of the second welding surface and the first welding surface, and the convex portion is arranged on the other of the second welding surface and the first welding surface; the side walls of the concave portion and the side walls of the convex portion are respectively arranged perpendicular to their respective corresponding welding surfaces; when the concave portion and the corresponding convex portion are matched, the relative side walls between the two are separated to form a gap of 0.05mm-0.5mm.

[0009] Optionally, the cross-sectional shape of the concave portion and the convex portion is rectangular or stepped; the depth of each side surface of the concave portion is 1 mm-5 mm; the height of each side surface of the convex portion is the same as the depth of each side surface of the concave portion.

[0010] Optionally, there are multiple recesses, which are spaced apart from each other; there are multiple convex portions corresponding to the concave portions, and the convex portions and the concave portions correspond one to one.

[0011] Optionally, each concave portion and convex portion is configured as an annular structure, and the multiple concave portions and the multiple convex portions are arranged in concentric circles.

[0012] Optionally, the total depths of the recesses are different; in a direction radiating outward from the center of the cooling plate, the total depths of the recesses decrease or increase.

[0013] Optionally, during the processing of the weldment, the recess is formed on the second welding surface;

[0014] During the assembly, the thermally conductive base is inverted so that the opening of the recess faces upward, and the support plate is placed above the thermally conductive base.

[0015] Optionally, a groove matching the contour shape of the support plate is formed on the bottom surface of the thermally conductive base, and the second welding surface is the bottom surface of the groove.

[0016] Optionally, during the vacuum brazing process, a constant pressure is applied to the assembled component, with the pressure being more than 1.5 times the weight of the upper welded part in the component.

[0017] Optionally, the thermally conductive base is made of aluminum alloy, the support plate is made of stainless steel, and the solder contains magnesium-silicon-aluminum, with the magnesium content ranging from 0.45% to 0.9% and the silicon content ranging from 0.2% to 0.6%.

[0018] Optionally, during the brazing process, the heating rate of the vacuum brazing equipment is controlled at 5-10°C / min.

[0019] Optionally, during the brazing process, vacuum brazing simultaneously meets the conditions that the vacuum degree is not less than 10-3Pa, the temperature is maintained at 580-620°C, and the holding time is at least 20 minutes.

[0020] Optionally, the nickel plating layer has a thickness of 5-30 μm.

[0021] In addition, the present invention further provides a cooling plate in the second aspect, which is manufactured by the cooling plate manufacturing method described in the first aspect, and a cooling water channel is provided inside the cooling plate, and the cooling water channel is arranged inside the heat-conducting base and / or support plate.

[0022] The cooling plate manufacturing method provided in this application uses selective nickel plating to perform nickel plating only on the first welding surface of the support plate, allowing the brazing layer to be directly connected to the second welding surface of the thermally conductive base. This method has significant advantages over existing composite layer metal brazing technology: the traditional process requires a nickel plating layer to be applied to both the inner and outer metal surfaces before welding, while this solution effectively avoids direct contact between the inner metal and the nickel layer by optimizing the nickel plating area. This improvement solves the technical problem in the traditional process of the nickel plating layer being loosely bonded to the inner metal layer and easily falling off due to differences in the material expansion coefficient.

[0023] Secondly, concave and convex limiting parts are processed on the second welding surface and the first welding surface respectively, and the radial expansion difference is effectively suppressed through the cooperation of the concave and convex limiting parts between the two welding surfaces.

[0024] These improvements significantly enhance the structural stability of the cooling plate manufactured using this method, optimize the thermal conductivity and enhance the overall mechanical strength.

[0025] These features and advantages of the present invention will be further disclosed in the following detailed description and accompanying drawings. The preferred embodiments and means of the present invention will be fully illustrated in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. Furthermore, although multiple features, elements, and components may be present in each of the following text and accompanying drawings, they may be labeled with different symbols or numbers for convenience, but all represent components with the same or similar structure or function. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings:

[0027] Figure 1 Flowchart of a method for manufacturing a cooling disk in some embodiments.

[0028] Figure 2 Schematic diagram of the structure of the cooling disk in some embodiments.

[0029] Figure 3 FIG. 8 is an exploded view of a cooling plate in some embodiments, illustrating the recessed portion of the first welding surface.

[0030] Figure 4 FIG. 1 is an exploded view of a cooling plate in some embodiments, showing the recessed portion of the first welding surface.

[0031] Figure 5 This is a partial enlarged view of the concave and convex limiting portion of the cooling plate in some embodiments, showing an implementation in which its cross-section is stepped.

[0032] Figure 6 Schematic diagram of the structure of the cooling plate in some embodiments, showing the concave and convex limiting parts arranged on the side walls of the groove.

[0033] Figure 7 Schematic diagram of the structure of the cooling plate in some embodiments, showing how the total depth of each recess decreases in a direction radiating outward from the center of the cooling plate.

[0034] Figure 8 Schematic diagram of the structure of the cooling plate in some embodiments, showing how the total depth of each recess increases in a direction radiating outward from the center of the cooling plate.

[0035] in,

[0036] 100, thermally conductive base; 110, second welding surface; 111, groove; 120, supporting surface;

[0037] 200, support plate; 210, first welding surface; 220, nickel plating layer;

[0038] 300, welding brazing layer;

[0039] 400. Concave and convex limiting part; 410. Concave part; 411. Edge concave part; 420. Protruding part; 421. Edge convex part;

[0040] 500. Cooling water channel. DETAILED DESCRIPTION

[0041] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described in the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention.

[0042] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0043] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0044] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more, and "a number of" means one or more.

[0045] References in this specification to "one embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment itself can be included in at least one embodiment disclosed herein. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0046] In semiconductor manufacturing, wafer cooling typically requires a dedicated container with a dedicated cooling plate at its base. Currently, the commonly used cooling plates are multi-layer composite structures. The inner layer, serving as the bottom of the container, is typically made of a metal with high thermal conductivity, such as aluminum alloy, to support the wafer and dissipate heat. The outer layer, such as stainless steel or titanium alloy, provides sufficient strength and maintains the smoothness of the inner layer. These multi-layer composite cooling plates are primarily manufactured using a vacuum brazing process. The following example illustrates a cooling plate with an inner aluminum alloy layer and an outer stainless steel layer.

[0047] Due to the special material purity requirements of semiconductor devices, heavy metal elements such as copper, lead, and mercury are strictly prohibited in brazing materials, making magnesium-silicon-aluminum solder almost the only viable option. However, this solder has significant process limitations: its wetting properties are significantly affected by temperature, and its wettability on aluminum alloy and stainless steel surfaces is poor, making it difficult for the brazing material to form a reliable adhesion to the contact surface. To address this problem, existing technology typically nickel-plates the welding surface of aluminum alloy and stainless steel before brazing to improve its solderability.

[0048] However, actual applications have shown that this treatment method still has obvious defects: due to the significant difference in the thermal expansion coefficients of aluminum alloy and nickel (the thermal expansion coefficient of aluminum alloy is about 23.6×10^-6 / ℃, while the thermal expansion coefficient of nickel is about 13.4×10^-6 / ℃), when the brazing temperature exceeds 500℃, this difference in thermal expansion coefficient will produce significant thermal stress during the subsequent cooling process. This thermal stress can cause the nickel layer to peel off from the aluminum alloy surface to varying degrees, leading to problems such as insufficient welding strength, microcracks, and peripheral warping. These defects will be exacerbated with the extension of usage time, eventually leading to a significant decline in the thermal conductivity of the cooling plate, affecting the uniform heat dissipation of the wafer, and thus reducing product yield.

[0049] To this end, this embodiment provides a cooling plate and a manufacturing method thereof to solve the problems of insufficient welding strength of the cooling plate, micro cracks on the welding surface, and peripheral warping, which have long-term stability and excellent thermal conductivity.

[0050] like Figure 1-4 The figure shows a flow chart of a method for manufacturing a cooling plate, a schematic diagram of the structure of the cooling plate, and an exploded view of the cooling plate (welding part). The cooling plate is used for semiconductors and mainly includes a heat-conducting base 100, a support plate 200, and a soldering brazing layer 300.

[0051] The heat-conducting base 100 has an opposite second welding surface 110 (see Figure 3 ) and support surface 120 (see Figure 2The support surface 120 is used to support and cool the wafer. Typically, the thermal base 100 is placed horizontally, with the support surface 120 being the area on its upper surface where the wafer is placed, and the second welding surface 110 being the area on the bottom surface corresponding to the support surface 120.

[0052] See also Figure 1 The support plate 200 has a first welding surface 210 and a nickel-plated layer 220 disposed on the first welding surface 210. Specifically, the support plate 200 has two opposing functionally partitioned surfaces along its thickness: the first welding surface 210 facing the heat-conducting base, and a heat dissipation surface facing away from the base. The heat dissipation surface achieves active heat exchange by embedding cooling channels.

[0053] The soldering layer 300 is located between the thermally conductive base 100 and the support plate 200 , and two sides of the soldering layer 300 are directly connected to the second soldering surface 110 and the nickel-plated layer 220 , respectively.

[0054] like Figure 1 As shown, the cooling plate manufacturing method mainly includes the following steps:

[0055] Step S200 : nickel plating treatment, performing nickel plating treatment on the first welding surface 210 of the support plate 200 to form a nickel plating layer 220 .

[0056] Step S300 , assembling, disposing solder on the nickel-plated layer 220 or on the second welding surface 110 of the thermally conductive base 100 , and then pressing the thermally conductive base 100 and the support plate against the solder and fixing them to complete the assembly.

[0057] Step S400, vacuum brazing, places the assembled heat-conducting base 100 and support plate 200 into a vacuum brazing device for brazing. During the brazing process, the solder melts and soaks the nickel-plated layer 220 and the second welding surface 110, and forms a brazing layer 300 after cooling. Figure 2 The soldering brazing layer 300 is directly connected to the nickel-plated layer 220 and the second soldering surface 110 respectively.

[0058] The cooling plate manufacturing method provided by the present invention first improves the weldability of the first welding surface by nickel plating on the first welding surface 210. The nickel plating layer 220 can be achieved by chemical nickel plating or electroplating. The chemical nickel plating process is preferably used. The coating thickness is preferably 5-30 microns. By controlling the coating thickness within the range of 5-30 microns, the metallurgical bonding strength of the nickel plating layer 220 and the first welding surface is guaranteed, and a reliable interface connection is formed between the nickel plating layer 220 and the soldering brazing layer 300 formed by the solder. This thickness range has been verified by experiments to balance bonding performance and cost-effectiveness.

[0059] Secondly, during the assembly process, appropriate assembly pressure is applied to the thermally conductive base 100 and support plate 200. This pressure can be achieved by utilizing the inherent weight of the welded parts, adding counterweights, or employing specialized fastening devices. During the brazing process, the molten solder, under pressure, can quickly and evenly fill the microscopic gap between the nickel-plated layer 220 and the second weld surface 110, achieving sufficient wetting of the interface. This pressure-assisted welding process not only significantly shortens the welding time but also effectively improves the mechanical strength of the joint interface.

[0060] The innovation of this invention lies in eliminating the nickel plating on the surface of the thermally conductive base 100 in the traditional process, and directly achieving a reliable connection between dissimilar metals through the optimized design of material composition. The advantages of this solution are: 1) Simplified process: It reduces several processes such as pre-plating treatment and post-plating inspection of one of the welded parts, shortening the manufacturing cycle; 2) Strengthened bonding: It avoids the interface brittle phase that may be generated between the nickel plating layer and the thermally conductive base, improving the connection reliability; 3) Improved thermal stability: It eliminates the fluctuation of contact thermal resistance caused by coating peeling. After thousands of hours of aging tests, the thermal conductivity coefficient attenuation rate is controlled within 3%, which has significant advantages over the existing structure (attenuation rate >12%) and can ensure that the heat dissipation uniformity of the wafer is maintained within the preset range for a long time.

[0061] As a preferred embodiment of the present invention, in order to further improve the bonding strength between the nickel plating layer and the second welding surface, before the vacuum brazing, the method further includes the following steps:

[0062] Step S100 , welding parts processing, processing the second welding surface 110 of the thermal conductive base 100 and the first welding surface 210 of the support plate 200 to form concave and convex limiting parts 400 that can be clearance-matched with each other.

[0063] The concave-convex stopper 400 can be a continuous, extended segment, such as a spiral, or can be a plurality of dispersed segments. The concave-convex stopper has a certain length, width, and depth (or height), with its length direction being the direction of extension. During welding surface processing, considering that the cooling plate is generally disc-shaped, the concave-convex stopper should be extended perpendicularly to the radial direction as much as possible, and its width direction should be consistent with the radial direction as much as possible.

[0064] The clearance fit between the concave and convex limiting portions 400 specifically refers to forming a certain gap on both sides in the width direction. The corresponding concave and convex limiting portions 400 have the same depth (or height).

[0065] Correspondingly, the nickel plating layer formed in the nickel plating process in step S200 covers the first welding surface 210 and the surface of the concave-convex limiting portion on the first welding surface.

[0066] Correspondingly, in the assembly of step S300, the area where the solder is arranged is a predetermined area on the nickel-plated layer 220 or on the second welding surface 110, and the predetermined area is each plane parallel to the second welding surface or the first welding surface; after the assembly is completed, the concave and convex limiting parts on the thermal conductive base and the support plate are in a clearance fit state.

[0067] Accordingly, during the soldering process of step S400, part of the liquid solder after melting fills the gap between the concave and convex limiting parts under capillary action; the solder fiber layer formed after the solder cools includes the part filling the gap between the concave and convex limiting parts.

[0068] Since the concave-convex limiting portion 400 is provided on the second welding surface 110 and the first welding surface 210, the predetermined area for laying the solder is not limited to the second welding surface 110 or the first welding surface 210, but also includes a portion of the surface of the concave-convex limiting portion 400, so as to ensure a secure connection after welding. The portion of the surface of the concave-convex limiting portion 400 is specifically each plane parallel to the second welding surface 110, such as the bottom surface, top surface or step surface of the concave-convex limiting portion. Moreover, since there is a gap fit between the side surfaces of the concave-convex limiting portion in its width direction, the solder on the bottom surface, top surface or step surface of the concave-convex limiting portion can fill the adjacent gap after melting, thereby reducing the flow path of the solder after melting, and to a certain extent shortening the time for the liquid solder to evenly fill the gap.

[0069] The use of vacuum brazing ensures that the thermally conductive base 100 and the support plate 200 are in a vacuum during the welding process. This allows the air in the gap between the concave and convex stoppers 400 to be extracted, allowing the solder to completely fill the gap after melting, increasing the solder contact area and preventing the possibility of internal cavitation. Furthermore, during the brazing process, capillary action is fully utilized, allowing the liquid solder to fill the gap under external pressure, vacuum, and capillary action.

[0070] In addition, the concave and convex limiting portion 400 matched between the two welding surfaces can limit the expansion difference between the second welding surface 110 and the nickel plating layer 220 in the radial direction of the cooling disk after welding.

[0071] Since the second welding surface 110 and the nickel-plated layer 220 have different thermal expansion coefficients, during the welding process, specifically the process from heating to cooling, the difference in their longitudinal contraction lengths on the cooling plate may be too large due to the different thermal expansion coefficients, thereby generating shear force on the bonding surface, thereby causing the bonding surface to fall off. Therefore, by providing a concave-convex limiting portion 400, the concave-convex limiting portion 400 of the second welding surface 110 can be interlocked with the concave-convex limiting portion 400 on the nickel-plated layer 220 (on the first welding surface), and a three-dimensional constraint is formed by mechanical interlocking: 1) Axial constraint: the concave-convex structure limits the separation between layers in the depth direction (thickness direction of the cooling plate); 2) Radial constraint: the limiting portions continuously distributed circumferentially form annular reinforcement ribs to control the radial strain difference within a preset range.

[0072] In step S100, during the welding process, the concave-convex stopper 400 includes a concave portion 410 and a convex portion 420. The concave portion 410 is provided on one of the second welding surface 110 and the first welding surface 210, and the convex portion 420 is provided on the other of the second welding surface 110 and the first welding surface 210. Figure 2 As shown, preferably, the concave portion 410 is provided on the second welding surface 110 , and the convex portion 420 is provided on the first welding surface 210 .

[0073] The extension direction of the recess 410 and / or the extension direction of the protrusion 420 is perpendicular to the radial direction of the cooling disk. Preferably, the recess 410 and the protrusion 420 extend along the circumferential direction of the cooling disk. The second welding surface 110 and the nickel-plated layer 220 on the first welding surface 210 are fixedly connected by the interlocking connection between the recess 410 and the protrusion 420, so that the second welding surface 110 and the nickel-plated layer 220 are completely anchored together in the local area where the recess 410 and the protrusion 420 are connected. Even if deformation occurs in the radial direction, it is relatively synchronized to avoid excessive expansion differences.

[0074] The side walls of the concave portion 410 and the side walls of the convex portion 420 are respectively arranged perpendicular to their respective corresponding welding surfaces. The side walls of the concave portion 410 and the side walls of the convex portion 420 are arranged opposite to each other, and a gap d with a width of 0.05mm-0.5mm is formed between the two. Figure 2 The nickel plating layer 220 and the soldering brazing layer 300 are sequentially filled into the gap.

[0075] It should be noted that, taking the preferred embodiment as an example, the sidewalls of the concave portion 410 are arranged perpendicular to the corresponding second welding surface 110, and the sidewalls of the convex portion 420 are arranged perpendicular to the corresponding first welding surface 210. Taking into account processing errors, perpendicularity means that the angle between the two surfaces is 90°±5°. By setting the sidewalls of the concave-convex limiter 400 to be perpendicular to the welding surface, when different degrees of thermal expansion deformation occur, the shear force generated on the welding surface can act perpendicularly on the sidewalls of the concave-convex limiter, avoiding the generation of a component force in the thickness direction that forces the second welding surface 110 and the nickel-plated layer 220 to separate.

[0076] Illustratively, the gap width between the sidewall of the concave portion 410 and the sidewall of the convex portion 420 is any one of 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, and 0.5 mm.

[0077] In some embodiments, the cross-sectional shape of the concave portion 410 and the convex portion 420 is rectangular or stepped. The depth of each side of the concave portion 410 is 1 mm to 5 mm. Figure 2 h1. The height of each side surface of the protrusion 420 is the same as the depth of each side surface of the recess 410. For recesses with a stepped cross-section, the stepped structure consists of two or more side surfaces, one or more step surfaces, and a bottom surface. The depth of each side surface is between 1 mm and 5 mm, so that the total depth of the recess 410 is greater than 5 mm.

[0078] Considering that the depth of the sidewalls of the concave-convex limiting portion 400 affects the filling of solder, in this embodiment, on the one hand, the sidewalls of the concave portion 410 and the sidewalls of the convex portion 420 are arranged opposite to each other, with a gap of 0.05mm-0.5mm in width formed therebetween, and on the other hand, by setting the depth of each side surface of the concave portion 410 to 1mm-5mm, a capillary effect can be utilized during soldering, allowing the molten solder to completely fill the gap under the capillary action, thereby completely bonding the second soldering surface 110 to the nickel-plated layer 220.

[0079] See also Figure 2 , for the concave portion 410 and the convex portion 420 having a rectangular cross-section, the concave portion 410 and the convex portion 420 have only one side wall in the thickness direction. Figure 5 For the concave portion 410 and the convex portion 420 with a stepped cross-sectional shape, the side walls of the concave portion 410 and the convex portion 420 are segmented in the thickness direction, and the depth of each (vertical) side wall is 1 mm to 5 mm. In this way, the capillary action of multiple sections of the side walls can be utilized to fill the gaps between the concave portion 410 and the convex portion 420 with a total depth greater than 5 mm.

[0080] For example, the depth of each side surface of the concave-convex limiting portion 400 is any one of 1 mm, 2 mm, 3 mm, 4 mm and 5 mm.

[0081] In some embodiments, see Figure 2-4 There are multiple recesses 410, and the multiple recesses 410 are spaced apart. There are multiple protrusions 420 corresponding to the recesses 410, and the protrusions 420 and the recesses 410 are arranged one by one. For example, the multiple recesses 410 are equidistant in the longitudinal direction. The width and depth of each recess 410 are the same.

[0082] In some embodiments, each recess 410 and protrusion 420 is configured as an annular structure, and the multiple recesses 410 and the multiple protrusions 420 are arranged in concentric circles. For example, the multiple concentrically arranged recesses are equidistantly spaced outward from the center of the cooling plate.

[0083] In some embodiments, the nickel plated layer 220 has a thickness of 5-30 μm, for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, and 30 μm.

[0084] In some embodiments, the total depth of each recess 410 is different. In the direction radiating outward from the center of the cooling plate, the total depth of each recess 410 decreases or increases.

[0085] Due to the difference in thermal expansion coefficients between the thermally conductive base 100 and the nickel-plated layer 220, when the two are welded together through the recessed limiting portion, the area farther away from the center has a greater degree of thermal expansion deformation. Therefore, in combination with the structural characteristics of the cooling plate, multiple recesses are set, and each recess can be set to a different total depth according to the degree of thermal expansion deformation, thereby improving its bonding strength. In addition, a stepped design is adopted so that the maximum total depth of the recess breaks through the limit of the capillary effect within 5mm.

[0086] As an optional embodiment of the present invention, Figure 7 The figure shows three recesses 410 with different total depths radiating outward from the center of the cooling plate, i.e., in the longitudinal direction. The recess with three stepped surfaces has a total depth of H1, the recess with two stepped surfaces has a total depth of H2, and the recess with one stepped surface has a total depth of H3. The depth of each stepped surface is the same, indicating that H1>H2>H3. In other words, the total depth of each recess decreases radiating outward from the center of the cooling plate. Accordingly, the protrusions are configured to match the stepped surface shape of the recesses.

[0087] As a preferred embodiment of the present invention, Figure 8As shown, it shows the way in which the total depth of each recess 410 increases in the direction radiating outward from the center of the cooling disk. The total depth corresponding to the recess with one step surface is H1, the total depth corresponding to the recess with two step surfaces is H2, and the total depth corresponding to the recess with three step surfaces is H3. The depth of each step surface is the same, so it can be seen that H3>H2>H1. Accordingly, the convex portion is set to a step surface shape that matches the recess. By setting a plurality of recesses with increasing depth in the direction away from the center of the cooling disk, the connection strength between the concave and convex limiting parts gradually increases with depth, and the connection strength between the recess and the convex portion located on the outermost side is the largest, thereby avoiding the warping phenomenon of the periphery of the support plate to the greatest extent. Moreover, compared to a cooling disk in which multiple recesses are all rectangular in the same size, the way in which the total depth of each recess 410 on the welding surface of this embodiment increases will cause its stress distribution to fluctuate with the height change of the recess, which can avoid relative concentration on the same welding surface.

[0088] In some embodiments, during the welding process, the recess 410 is formed on the second welding surface 110. During the assembly process, the thermally conductive base 100 is inverted so that the opening of the recess 410 faces upward, and the support plate 200 is placed above the thermally conductive base 100.

[0089] Since the second welding surface 110 is located on the bottom surface of the thermally conductive base 100, when the thermally conductive base 100 is inverted, the second welding surface 110 is facing upward and located above the recess. Therefore, after the solder on the second welding surface melts, it can flow to the side gap of the recess under the action of gravity, and at the same time, it can cooperate with the capillary action of the liquid solder on the bottom surface of the recess to fill the side gap of the recess.

[0090] In some embodiments, as Figure 6 As shown, the bottom surface of the thermal conductive base 100 is provided with a groove 111 adapted to the contour shape of the support plate 200, and the second welding surface 110 is the bottom surface of the groove 111. Specifically, the depth of the groove 111 is greater than the thickness of the support plate 200, so that the support plate 200 can be completely embedded in the depth of the groove 111.

[0091] As a preferred embodiment of the present invention, in order to improve the connection strength between the support plate 200 and the side wall of the groove 111 and avoid the warping phenomenon around the support plate, among the multiple concentric concave and convex limiting parts 400 on the bottom surface of the groove 111, an edge protrusion 421 located on the outermost side is arranged at the connection between the bottom surface of the groove 111 and the side wall to form a stepped surface. Correspondingly, the first welding surface 210 of the support plate 200 is also provided with a corresponding edge recess 411 around it. In this way, a stepped surface is also formed on the side of the support plate 200. According to the thickness of the support plate, the number of steps can be flexibly set while meeting the height of the stepped surface, so as to facilitate the use of capillary action to fill the solder in the gap between the two during welding and complete the welding.

[0092] In some embodiments, during the vacuum brazing process, a constant pressure is applied to the assembled component, and the pressure is greater than 1.5 times the weight of the upper welded part in the component.

[0093] For example, the pressure is twice the weight of the support plate. By applying constant pressure, during the brazing process, after the solder melts, the applied pressure can improve the contact between the molten solder, the nickel-plated layer, and the second welding surface, and also make it relatively easy for the gap between the concave and convex stoppers to be filled with solder due to capillary action.

[0094] In some embodiments, the thermally conductive base is made of aluminum alloy, the support plate is made of stainless steel, and the solder contains magnesium-silicon-aluminum, with the magnesium content ranging from 0.45% to 0.9% and the silicon content ranging from 0.2% to 0.6%. To achieve optimal surface quality and product hardness, the magnesium content is preferably controlled between 0.56% and 0.58%, and the silicon content is preferably controlled between 0.38% and 0.40%.

[0095] In some embodiments, during the brazing process, the heating rate of the vacuum brazing equipment is controlled at 5-10°C / min to avoid excessive thermal stress caused by excessive heating.

[0096] In some embodiments, during the brazing process, vacuum brazing is performed while maintaining a vacuum degree of not less than 10 -3 Pa, the temperature is maintained at 580-620℃, and the holding time is at least 20 minutes. After welding, the furnace cooling method is used to reduce the residual stress of the weld joint.

[0097] In some embodiments, when the nickel plating process is performed, the thickness of the nickel plating layer 220 is preferably 5-30 μm.

[0098] In a second aspect, this embodiment further provides a cooling plate, which is manufactured by the cooling plate manufacturing method of the first aspect. Figure 2As shown, the interior of the cooling plate is provided with a cooling water channel 500, and the cooling water channel 500 is arranged inside the heat-conducting base 100 and / or the support plate 200. Preferably, the cooling water channel 500 is buried in the support plate 200.

[0099] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A method for manufacturing a cooling plate for a semiconductor, characterized in that: The cooling plate manufacturing method comprises: Nickel plating treatment, performing nickel plating treatment on the first welding surface (210) of the support plate (200) to form a nickel plating layer (220); Assembling, disposing solder on the nickel-plated layer (220) or on the second welding surface (110) of the heat-conducting base (100), and then pressing the heat-conducting base and the support plate against the solder and fixing them to complete the assembly; Vacuum brazing, wherein the assembled heat-conducting base (100) and the support plate (200) are placed in a vacuum brazing device for brazing treatment; during the brazing process, the solder melts and infiltrates the nickel-plated layer (220) and the second welding surface (110), and forms a brazing layer (300) after cooling; the brazing layer is directly connected to the nickel-plated layer (220) and the second welding surface (110), respectively.

2. The method for manufacturing a cooling plate according to claim 1, wherein: Before the vacuum brazing, the method further comprises: Welding parts processing, respectively processing the second welding surface (110) of the heat-conducting base (100) and the first welding surface (210) of the support plate (200) to form concave and convex limiting portions (400) capable of mutual clearance fit; Correspondingly, the nickel plating layer formed in the nickel plating process covers the first welding surface (210) and the surface of the concave-convex limiting portion on the first welding surface; The area where the solder is arranged during the assembly is a predetermined area on the nickel-plated layer (220) or on the second welding surface (110), and the predetermined area is each plane parallel to the second welding surface or the first welding surface; after the assembly is completed, the concave and convex limiting portions on the heat-conducting base and the support plate are in a clearance fit state; During the brazing process, part of the liquid solder after melting fills the gap between the concave and convex limiting parts under capillary action; the welding fiber layer formed after the solder cools includes the part filling the gap between the concave and convex limiting parts.

3. The method for manufacturing a cooling plate according to claim 2, wherein: In the welding part processing, the concave-convex limiting portion (400) includes a concave portion (410) and a convex portion (420); The concave portion (410) is provided on one of the second welding surface (110) and the first welding surface (210), and the convex portion (420) is provided on the other of the second welding surface (110) and the first welding surface (210); The side walls of the concave portion (410) and the side walls of the convex portion (420) are respectively arranged perpendicular to their corresponding welding surfaces; when the concave portion (410) and the corresponding convex portion (420) are matched, the opposite side walls therebetween are spaced to form a gap of 0.05mm-0.5mm.

4. The method for manufacturing a cooling plate according to claim 3, wherein: The cross-sectional shapes of the concave portion (410) and the convex portion (420) are rectangular or stepped; the depth of each side surface of the concave portion (410) is 1 mm to 5 mm; the height of each side surface of the convex portion (420) is the same as the depth of each side surface of the concave portion (410).

5. The method for manufacturing a cooling plate according to claim 3, wherein: There are a plurality of concave portions (410), and the concave portions (410) are spaced apart from each other; there are a plurality of convex portions (420) corresponding to the concave portions (410), and the convex portions (420) and the concave portions (410) correspond to each other one by one.

6. The method for manufacturing a cooling plate according to claim 5, wherein: Each concave portion (410) and convex portion (420) is configured as an annular structure, and the multiple concave portions (410) and the multiple convex portions (420) are arranged in concentric circles.

7. The method for manufacturing a cooling plate according to claim 6, wherein: The total depths of the recesses are different; in a direction radiating outward from the center of the cooling plate, the total depths of the recesses decrease or increase.

8. The method for manufacturing a cooling plate according to claim 3, wherein: During the welding process, the recess (410) is formed on the second welding surface (110); During the assembly, the thermally conductive base (100) is inverted so that the opening of the recess (410) faces upward, and the support plate (200) is placed above the thermally conductive base (100).

9. The method for manufacturing a cooling plate according to any one of claims 1 to 8, characterized in that: The bottom surface of the heat-conducting base (100) is provided with a groove (111) adapted to the contour shape of the support plate (200), and the second welding surface (110) is the bottom surface of the groove (111); Alternatively, during vacuum brazing, a constant pressure is applied to the assembled component, the pressure being at least 1.5 times the weight of the upper welded part of the component; Alternatively, the thermally conductive base is made of aluminum alloy, the support plate is made of stainless steel, and the solder contains magnesium-silicon-aluminum, with the magnesium content ranging from 0.45% to 0.9% and the silicon content ranging from 0.2% to 0.6%; Alternatively, during the brazing process, control the heating rate of the vacuum brazing equipment at 5-10°C / min; Alternatively, during the brazing process, vacuum brazing should meet the vacuum degree of not less than 10 -3 Pa, the temperature is maintained at 580-620℃, and the holding time is at least 20min; Alternatively, the nickel plating layer (220) has a thickness of 5-30 μm.

10. A cooling plate, manufactured by the cooling plate manufacturing method according to any one of claims 1 to 9, characterized in that: A cooling water channel (500) is provided inside the cooling plate, and the cooling water channel (500) is arranged inside the heat-conducting base (100) and / or the support plate (200).

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