Ceramic Substrate Welding Method with Pre-Placed Welding Alloy Material and Ceramic Substrate Welded Component

Abstract

The present invention discloses a welding method for a ceramic substrate with a pre-set welding alloy material and a welded ceramic substrate. The method includes covering the upper surface and the lower surface of a ceramic sheet with an oxygen-free copper sheet and performing vacuum high-temperature brazing sintering to form a copper-clad ceramic substrate; exposing and developing a circuit pattern on the front surface of the copper-clad ceramic substrate; performing copper etching according to the developing result to form a front surface circuit of the substrate; performing secondary etching on the positions corresponding to the lead frame terminals in the upper copper layer of the copper-clad ceramic substrate to form grooves; pouring a molten welding alloy material into the grooves to fill the grooves and cooling to form spherical pre-set welding alloy materials higher than the surface of the copper-clad ceramic substrate; and mounting a chip on the upper surface of the copper-clad ceramic substrate and welding metal wires well. By pre-setting the welding alloy material in the grooves on the copper-clad ceramic substrate, the present invention improves the welding quality, simplifies the production process, and reduces the production cost.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular, to a welding method for a ceramic substrate with a pre-placed welding alloy material and a ceramic substrate welding part. Background Art

[0002] In the existing semiconductor packaging technology field, the placement of solder pads may deviate from the design requirements due to the positioning error of the manipulator, which will affect the contact between the welding alloy material and the back surface of the lead frame terminal, and further affect the welding quality. There may be a large gap between the solder pad and the copper surface of the substrate, which will cause abnormal voids in the welding alloy material during the reflow soldering process. The welding alloy material may randomly diffuse after melting, resulting in the welding alloy material overflowing beyond the range, which not only affects the welding quality but may also damage the surrounding structures. During vacuum formic acid reflow soldering, abnormal phenomena such as poor wetting and voids of the welding alloy material may occur, which not only reduces the welding quality but also affects the overall performance of the product. Summary of the Invention

[0003] An embodiment of the present invention provides a welding method for a ceramic substrate with a pre-placed welding alloy material and a ceramic substrate welding part, aiming to solve the problem of low welding yield between the lead frame terminal and the ceramic substrate in the existing technical methods.

[0004] In a first aspect, an embodiment of the present invention discloses a welding method for a ceramic substrate with a pre-placed welding alloy material. The method includes covering the upper surface and the lower surface of a ceramic sheet with an oxygen-free copper sheet and performing vacuum high-temperature brazing sintering to form a copper-clad ceramic substrate; performing circuit pattern exposure and development on the front surface of the copper-clad ceramic substrate; performing copper etching according to the development result to form a front surface circuit of the substrate; performing secondary etching on the position corresponding to the lead frame terminal in the upper copper layer of the copper-clad ceramic substrate to form a groove; pouring the molten welding alloy material into the groove to fill the groove and cooling it to form a spherical pre-placed welding alloy material higher than the surface of the copper-clad ceramic substrate; mounting a chip on the upper surface of the copper-clad ceramic substrate and welding metal wires; fixing the copper-clad ceramic substrate in a pre-set co-packaging fixture through the lead frame terminal and placing a gravity pressing plate, and performing vacuum formic acid reflow soldering on the spherical pre-placed welding alloy material to melt the spherical pre-placed welding alloy material and form a glue-climbing structure to firmly weld the lead frame terminal and the copper layer of the copper-clad ceramic substrate.

[0005] Second aspect, embodiments of the present invention disclose a ceramic substrate weldment, which is produced by applying the above-mentioned ceramic substrate welding method with pre-placed welding alloy material. The weldment includes a copper-clad ceramic substrate, a lead frame terminal, and a spherical pre-placed welding alloy material; the copper-clad ceramic substrate includes a ceramic sheet and an oxygen-free copper sheet, and the oxygen-free copper sheet covers the upper surface and the lower surface of the ceramic sheet to form the copper-clad ceramic substrate. A groove is provided on the upper surface of the copper-clad ceramic substrate for forming the spherical pre-placed welding alloy material, and the lead frame terminal is welded to the copper-clad ceramic substrate through the spherical pre-placed welding alloy material.

[0006] The above-mentioned welding method eliminates the redundant gaps in the weldment by pre-placing the welding alloy material in the groove, enabling the welding alloy material to come into full contact with the copper surface of the substrate, thereby avoiding the occurrence of void problems. By restricting the flow space of the welding alloy material, the random diffusion of the welding alloy material after melting is avoided, and the problem of the welding alloy material overflowing beyond the scope occurs. By pre-placing the welding alloy material in the groove, its flow space is restricted, ensuring the accurate distribution of the welding alloy material. The operations of cutting and installing the solder pad during the encapsulation process are cancelled, simplifying the encapsulation process, thereby reducing the module encapsulation difficulty and equipment cost, and enhancing the market competitiveness. By pre-placing the welding alloy material in the groove, the complexity of the product manufacturing process is reduced, and the cost is lowered. Moreover, pre-placing the welding alloy material in the groove on the copper-clad ceramic substrate not only improves the welding quality, simplifies the production process, but also reduces the production cost, thereby enhancing the overall market competitiveness. Description of the Drawings

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0008] Figure 1 It is a schematic diagram of the main steps of the ceramic substrate welding method with pre-placed welding alloy material provided by the embodiments of the present invention;

[0009] Figure 2 It is a schematic diagram of the sub-steps of the ceramic substrate welding method with pre-placed welding alloy material provided by the embodiments of the present invention;

[0010] Figure 3 It is a schematic diagram of the welding process of the ceramic substrate welding method with pre-placed welding alloy material provided by the embodiments of the present invention;

[0011] Figure 4 It is a schematic diagram of the structure of the solder pad welding operation of the copper-clad ceramic substrate in the prior art;

[0012] Figure 5Schematic diagram of the relationship between the lead frame terminal and the groove provided by the embodiment of the present invention.

[0013] Reference numerals in the attached drawings:

[0014] 1. Sealing fixture; 2. Oxygen-free copper sheet; 3. Circuit on the front side of the substrate; 4. Ceramic sheet; 5. Spherical pre-placed welding alloy material; 6. Groove; 7. Lead frame terminal; 8. Gravity pressing plate; 9. Solder sheet. Detailed implementation manners

[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0016] It should be understood that when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0017] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0018] It should be further understood that the term " / and / " used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0019] In the first aspect, as Figure 1 shown, a welding method for a ceramic substrate with a pre-placed welding alloy material provided in this embodiment includes steps S110 - S170.

[0020] S110. Cover the upper and lower surfaces of the ceramic sheet 4 with the oxygen-free copper sheet 2 and perform vacuum high-temperature brazing sintering to form a copper-clad ceramic substrate.

[0021] Specifically, step S110 further includes the following steps: A layer of brazing alloy material is coated on both the upper surface and the lower surface of the ceramic chip 4 as a bonding layer. After coating, the ceramic chip 4 is aligned with the oxygen-free copper sheet 2 to ensure that the oxygen-free copper sheet 2 completely covers the upper surface and the lower surface of the ceramic chip 4. The oxygen-free copper sheet 2 and the ceramic chip 4 are placed in a vacuum environment for high-temperature brazing sintering to form a copper-clad ceramic substrate.

[0022] In an actual usage scenario, please refer to Figure 3 (a-d). First, a layer of brazing alloy material is coated on both the upper and lower surfaces of the ceramic chip 4. This layer of material will serve as a bonding layer to enhance the bonding force between the oxygen-free copper sheet and the ceramic chip 4.

[0023] S120. Expose and develop the circuit pattern on the front side of the copper-clad ceramic substrate.

[0024] Specifically, as Figure 2 shown, step S120 further includes steps S121 - S125:

[0025] S121. Generate circuit layout information according to the preset circuit pattern on the front side of the copper-clad ceramic substrate, which is used to verify the connection requirement effect of electrical components during the circuit pattern exposure and development process.

[0026] S122. Draw the circuit pattern according to the circuit layout information and generate a mask for exposure and development.

[0027] S123. Expose and develop the circuit pattern on the front side of the copper-clad ceramic substrate through the mask.

[0028] S124. Place the copper-clad ceramic substrate on the exposure machine for precise alignment.

[0029] S125. Expose the front side of the copper-clad ceramic substrate through the mask for developing the circuit pattern, so as to realize the exposure and development of the circuit pattern on the front side of the copper-clad ceramic substrate.

[0030] S130. Perform copper etching according to the development result to form the front-side circuit 3 of the substrate.

[0031] Preferably, before step S130, there is also a step: preset etching control information, where the etching control information includes etching time, etching temperature, line width, and trace depth.

[0032] S140. Perform secondary etching on the position corresponding to the lead frame terminal 7 in the upper copper layer of the copper-clad ceramic substrate to form a groove 6.

[0033] Preferably, step S140 further includes the steps of: pre-marking the positions of the lead frame terminals 7 in the upper copper layer of the copper-clad ceramic substrate; performing secondary etching on the upper copper layer of the copper-clad ceramic substrate according to the marking and preset etching control information to form a groove 6 that meets the preset etching depth and etching width. Pouring the molten soldering alloy material into the groove 6 to fill the groove 6 and then cooling it to form a spherical pre-placed soldering alloy material 5 that is higher than the surface of the copper-clad ceramic substrate.

[0034] Preferably, step S150 further includes the steps of: melting the soldering alloy material according to the preset thermal melting temperature. Pouring the molten soldering alloy material evenly into the groove 6 and removing the bubbles. Cooling the molten soldering alloy material to ensure that the soldering alloy material forms a spherical pre-placed soldering alloy material 5 that is higher than the surface of the copper-clad ceramic substrate.

[0035] S160. Mount the chip on the upper surface of the copper-clad ceramic substrate and weld the metal wires well.

[0036] S170. Fix the copper-clad ceramic substrate in the preset co-packaging jig 1 through the lead frame terminals 7 and place the gravity pressing plate 8, and perform vacuum formic acid reflow soldering on the spherical pre-placed soldering alloy material 5 to melt the spherical pre-placed soldering alloy material 5 and form a gum-crawling structure to firmly weld the lead frame terminals 7 to the copper layer of the copper-clad ceramic substrate.

[0037] Preferably, step S170 includes the steps of: melting the soldering alloy material according to the preset thermal melting temperature. Pouring the molten soldering alloy material evenly into the groove 6 and removing the bubbles. Cooling the molten soldering alloy material to ensure that the soldering alloy material forms a spherical pre-placed soldering alloy material 5 that is higher than the surface of the copper-clad ceramic substrate.

[0038] Preferably, as Figure 5 shown, the numerical value of the matching range X of the length of the groove 6 and the size of the lead frame terminal 7 is 0.10 - 0.20 mm, the numerical value of the matching range Y of the width of the groove 6 and the size of the lead frame terminal 7 is 0.10 - 0.20 mm, and the numerical relationship between the depth H of the groove 6 and the thickness T of the oxygen-free copper sheet 2 can preferably be designed as: 1 / 3T ≤ H ≤ 1 / 2T.

[0039] Next, the coated oxygen-free copper sheet 2 and the ceramic sheet 4 are precisely aligned to ensure that the oxygen-free copper sheet 2 completely covers the upper and lower surfaces of the ceramic sheet 4 without any gaps. Then, the oxygen-free copper sheet 2 and the ceramic sheet 4 are placed in a vacuum environment for high-temperature brazing sintering. This process not only forms the copper-clad ceramic substrate but also ensures the tight bonding between the oxygen-free copper sheet 2 and the ceramic sheet 4. According to the preset circuit pattern on the front side of the copper-clad ceramic substrate, circuit layout information is generated. This information is used to verify the connection requirements and effects of electrical components during the exposure and development process to ensure the accuracy of the circuit design. Based on the circuit layout information, a detailed circuit pattern is drawn, and a mask for exposure and development is generated accordingly. The copper-clad ceramic substrate is placed on the exposure machine for precise alignment, and then the front side of the substrate is exposed through the mask to develop the circuit pattern. This step is crucial for forming precise circuits. Before copper etching, etching control information is preset, including parameters such as etching time, etching temperature, circuit width, and trace depth, to ensure precise control of the etching process. According to the development result, the copper-clad ceramic substrate is placed in the etching solution for copper etching to form the circuit on the front side of the substrate. In the upper copper layer of the copper-clad ceramic substrate, the positions corresponding to the lead frame terminals 7 are precisely marked. According to the marks and the preset etching control information, the upper copper layer is etched twice to form grooves 6 that match the size of the lead frame terminals 7. According to the preset thermal melting temperature, the welding alloy material is melted and evenly poured into the grooves 6. Bubbles are excluded during the pouring process, and then the molten welding alloy material is cooled to ensure the formation of spherical pre-placed welding alloy materials 5 that are higher than the surface of the copper-clad ceramic substrate. Chip mounting is performed on the upper surface of the copper-clad ceramic substrate, and metal wires are welded to prepare for subsequent packaging steps. The copper-clad ceramic substrate is fixed in the preset co-packaging fixture 1, and a gravity pressure plate 8 is placed. Subsequently, the entire assembly is sent into a vacuum formic acid reflow soldering furnace for reflow soldering. As Figure 3 shown in (d), during the reflow soldering process, the molten welding alloy material forms a glue-climbing structure under the action of the gravity pressure plate 8 and is firmly welded to the back and surrounding sides of the lead frame terminals 7, forming a high-strength electrical connection. By pre-placing the welding alloy material in the grooves 6, the positioning error during the placement of traditional solder pads is avoided, ensuring the accuracy of the welding position. The pre-placed welding alloy material can fully contact the lead frame terminals 7, reducing the risk of poor wetting and voids and improving the consistency and reliability of welding. The steps of cutting, handling, and placing traditional solder pads are omitted, which not only simplifies the packaging process but also reduces production costs. The pre-placed welding alloy material forms a more solid welding connection between the lead frame terminals 7 and the copper layer of the copper-clad ceramic substrate.

[0040] In summary, compared with the prior art, as Figure 4As shown, in the prior art, the soldering operation of the copper-clad ceramic substrate and the solder pad requires relying on the solder pad. In the manufacturing process of the power module product packaging, between the lead frame terminal 7 and the upper copper layer of the copper-clad ceramic substrate 4 (such as Figure 4 shown in a), the vacuum formic acid reflow soldering process is required, so that the solder pad 9 melts at high temperature and then bonds. Before performing the vacuum formic acid reflow soldering, the positioning and arrangement of the copper-clad ceramic substrate 4, the solder pad 9 and the lead frame terminal 7 need to go through the following steps: Place the copper-clad ceramic substrate 4 in the co-packaging fixture; According to the size of the lead frame terminal, cut out small solder pads with the required thickness that match it; The equipment manipulator grabs and places the cut solder pads one by one in the designated area on the surface of the copper-clad ceramic substrate 4; Fix the lead frame on the surface of the copper-clad ceramic substrate, and at the same time ensure that the lead frame terminal 7 is directly above the solder pad; Place a gravity pressing plate directly above the lead frame terminal 7 to press and fix the lead frame terminal 7, the solder pad 9, and the copper-clad ceramic substrate 4; Through the vacuum formic acid reflow soldering, the solder pad is melted, so that the back surface of the lead frame terminal 7 and the surface of the upper copper layer of the copper-clad ceramic substrate 4 are welded together through the solder pad alloy to complete the co-packaging between the frame and the copper-clad ceramic substrate. During this process, due to certain errors in the positioning of the equipment manipulator, the actual placement position of the solder pad 9 cannot be exactly the same as the design requirements. In addition, after the manipulator finishes placing the solder pad 9, the solder pad 9 may also be displaced due to the vibration of the equipment. Therefore, before entering the vacuum formic acid reflow soldering furnace, there may actually be a deviation in the relative position between the solder pad 9 and the lead frame terminal 7 (such as Figure 4 shown in w). At the same time, since the back surface of the solder pad 9 cannot be completely attached to the surface of the copper-clad ceramic substrate 4, there is a certain gap (such as Figure 4As shown in Figure s, during the reflow soldering process, the solder pads 9 are blown by hot air, which increases the probability and size of the solder pad displacement. Therefore, after vacuum formic acid reflux, the welding alloy material cannot completely wrap the back and the surrounding sides of the lead frame terminal 7, resulting in insufficient wetting rate of the welding alloy material. At the same time, affected by the hot air blowing, the voids of the welding alloy material exceed the standard, which not only reduces the bonding strength between the lead frame terminal 7 and the copper-clad ceramic substrate 4, but also weakens the electrical conversion ability and heat dissipation efficiency between the lead frame terminal 7 and the copper-clad ceramic substrate 4. The present invention claims a structure and method for pre-placing the welding alloy material in the specified groove 6 of the upper copper layer of the copper-clad ceramic substrate. By pre-placing the welding alloy material in the groove 6, the poor wetting of the welding alloy material caused by the position deviation of the solder pad 9 is avoided. In the traditional technology, the accuracy of the solder pad placement is limited by the positioning accuracy of the manipulator, while in the present invention, by pre-forming the groove 6 on the substrate, the welding alloy material can be accurately placed in the predetermined position, thereby improving the welding quality. Due to the large gap that may exist between the solder pad and the copper surface of the copper-clad ceramic substrate, void abnormalities may occur. In the present invention, by pre-placing the welding alloy material in the groove 6, this gap is eliminated, enabling the welding alloy material to fully contact the copper surface of the substrate, thus avoiding the occurrence of void problems. By restricting the flow space of the welding alloy material, the random diffusion of the welding alloy material after melting is avoided, preventing the problem of the welding alloy material overflowing beyond the specified range. In the traditional technology, the solder pad may move due to heat during the reflow soldering process, resulting in the overflow of the welding alloy material. In the present invention, by pre-placing the welding alloy material in the groove 6, its flow space is restricted, ensuring the accurate distribution of the welding alloy material. The present invention eliminates the operations of cutting and installing the solder pads during the encapsulation process, simplifies the encapsulation process, thereby reducing the module encapsulation difficulty and equipment cost, and enhancing the market competitiveness. In the traditional technology, the cutting and installation of the solder pads require additional labor and equipment investment. In the present invention, by pre-placing the welding alloy material in the groove 6, this step is directly skipped, reducing the complexity and cost in the production process. By pre-placing the welding alloy material in the groove 6 on the copper-clad ceramic substrate, not only the welding quality is improved, the production process is simplified, but also the production cost is reduced, thereby enhancing the overall market competitiveness.

[0041] The embodiment of the present invention also discloses a ceramic substrate welded part, which is manufactured by applying the above-mentioned ceramic substrate welding method for pre-placing the welding alloy material. The welded part includes a copper-clad ceramic substrate, a lead frame terminal 7, and a spherical pre-placed welding alloy material 5; the copper-clad ceramic substrate includes a ceramic sheet 4 and an oxygen-free copper sheet 2. The oxygen-free copper sheet covers the upper surface and the lower surface of the ceramic sheet 4 to form the copper-clad ceramic substrate. A groove 6 is provided on the upper surface of the copper-clad ceramic substrate for forming the spherical pre-placed welding alloy material 5. The lead frame terminal 7 is welded to the copper-clad ceramic substrate through the spherical pre-placed welding alloy material 5.

[0042] An embodiment of the present invention discloses a method for welding a ceramic substrate with a pre-placed welding alloy material and a welded ceramic substrate. The method includes covering the upper and lower surfaces of a ceramic sheet 4 with an oxygen-free copper sheet 2 and performing vacuum high-temperature brazing sintering to form a copper-clad ceramic substrate; exposing and developing a circuit pattern on the front surface of the copper-clad ceramic substrate; performing copper etching according to the development result to form a front surface circuit 3 of the substrate; performing secondary etching on the position corresponding to the lead frame terminal 7 in the upper copper layer of the copper-clad ceramic substrate to form a groove 6; pouring the molten welding alloy material into the groove 6 to fill the groove 6 and cooling it to form a spherical pre-placed welding alloy material 5 higher than the surface of the copper-clad ceramic substrate; mounting a chip on the upper surface of the copper-clad ceramic substrate and welding metal wires; fixing the copper-clad ceramic substrate in a pre-set co-packaging fixture 1 through the lead frame terminal 7 and placing a gravity pressing plate 8, and performing vacuum formic acid reflow soldering on the spherical pre-placed welding alloy material 5 to melt the spherical pre-placed welding alloy material 5 and form a gum climbing structure to firmly weld the lead frame terminal 7 to the copper layer of the copper-clad ceramic substrate. The welded part includes a copper-clad ceramic substrate, a lead frame terminal 7, and a spherical pre-placed welding alloy material 5; the copper-clad ceramic substrate includes a ceramic sheet 4 and an oxygen-free copper sheet 2, and the oxygen-free copper sheet covers the upper and lower surfaces of the ceramic sheet 4 to form a copper-clad ceramic substrate. A groove 6 is provided on the upper surface of the copper-clad ceramic substrate for forming the spherical pre-placed welding alloy material 5, and the lead frame terminal 7 is welded to the copper-clad ceramic substrate through the spherical pre-placed welding alloy material 5.

[0043] The method for welding a ceramic substrate with a pre-placed welding alloy material and the welded ceramic substrate disclosed in the embodiment of the present invention solve the problems of poor wetting of the welding alloy material caused by the deviation of the position of the solder sheet in the traditional technology, abnormal voids caused by a large gap between the solder sheet and the copper surface of the substrate, the problem of overflow beyond the range caused by the random diffusion of the welding alloy material after melting, and the cumbersome and cost increase brought by the actions of cutting and installing the solder sheet during the packaging process. Generally, the yield rate of the welded product is improved. By pre-placing the welding alloy material in the groove 6 on the copper-clad ceramic substrate, the welding quality is improved, the production process is simplified, the module packaging difficulty and equipment cost are reduced, and the market competitiveness is enhanced.

[0044] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for welding a ceramic substrate with a pre-set welding alloy material, characterized in that: include: Covering the upper and lower surfaces of the ceramic sheet with an oxygen-free copper sheet and performing vacuum high-temperature brazing and sintering to form a copper-clad ceramic substrate; Expose and develop a circuit pattern on the front side of the copper-clad ceramic substrate; Perform copper etching according to the development result to form a front circuit of the substrate; Performing secondary etching on the position corresponding to the lead frame terminal in the upper copper layer of the copper-clad ceramic substrate to form a groove; Pouring a molten welding alloy material into the groove to fill the groove and cooling the groove to form a spherical pre-set welding alloy material higher than the surface of the copper-clad ceramic substrate; Mounting a chip on the upper surface of the copper-clad ceramic substrate and welding a metal wire; The copper-clad ceramic substrate is fixed in a preset sealing fixture through a lead frame terminal and a gravity pressure plate is placed, and the spherical preset welding alloy material is subjected to vacuum formic acid reflow soldering to melt the spherical preset welding alloy material and form a creeping glue structure so that the lead frame terminal and the copper layer of the copper-clad ceramic substrate are firmly welded.

2. The method for welding a ceramic substrate with a pre-set welding alloy material according to claim 1, characterized in that: The method of covering the upper surface and the lower surface of the ceramic sheet with an oxygen-free copper sheet and performing vacuum high-temperature brazing and sintering to form a copper-clad ceramic substrate comprises: Coating a layer of brazing alloy material as a bonding layer on the upper surfaces of the oxygen-free copper sheet and the ceramic sheet; Aligning the coated oxygen-free copper sheet and the ceramic sheet to ensure that the oxygen-free copper sheet completely covers the upper surface and the lower surface of the ceramic sheet; The oxygen-free copper sheet and the ceramic sheet are placed in a vacuum environment for high-temperature brazing and sintering to form a copper-clad ceramic substrate.

3. The method for welding a ceramic substrate with a pre-set welding alloy material according to claim 2, characterized in that: The method of exposing and developing the circuit pattern on the front side of the copper-clad ceramic substrate comprises: Generate circuit layout information according to the preset circuit pattern on the front side of the copper-clad ceramic substrate, so as to verify the connection requirements of electrical components during the exposure and development process of the circuit pattern; Drawing a circuit pattern according to the circuit layout information and generating a mask for the exposure and development; The front surface of the copper-clad ceramic substrate is exposed and developed with a circuit pattern through the mask.

4. The method for welding a ceramic substrate with a pre-set welding alloy material according to claim 3, characterized in that: The method of exposing and developing the circuit pattern on the front side of the copper-clad ceramic substrate comprises: Placing the copper-clad ceramic substrate on an exposure machine for precise alignment; The front side of the copper-clad ceramic substrate is exposed through the mask to develop the circuit pattern, so as to realize exposure and development of the circuit pattern on the front side of the copper-clad ceramic substrate.

5. The method for welding a ceramic substrate with a pre-set welding alloy material according to claim 4, characterized in that: Before copper etching is performed according to the development result to form a front circuit of the substrate, the method comprises: The etching control information is preset, and the etching control information includes etching time, etching temperature, line width and routing depth.

6. The method for welding a ceramic substrate with a pre-set welding alloy material according to claim 5, characterized in that: The step of performing secondary etching on the position corresponding to the lead frame terminal in the upper copper layer of the copper-clad ceramic substrate to form a groove comprises: Pre-marking the position of the lead frame terminal in the upper copper layer of the copper-clad ceramic substrate; The upper copper layer of the copper-clad ceramic substrate is etched for a second time according to the mark and the preset etching control information to form a groove that meets the preset etching depth and etching width.

7. The method for welding a ceramic substrate with a pre-set welding alloy material according to claim 6, characterized in that: The step of pouring the molten welding alloy material into the groove to fill the groove and cooling the groove comprises: Melting the welding alloy material according to a preset hot melting temperature; Evenly pouring the molten welding alloy material into the groove and removing bubbles; The molten solder alloy material is cooled to ensure that the solder alloy material forms a spherical pre-set solder alloy material above the surface of the copper-clad ceramic substrate.

8. A ceramic substrate welded part, manufactured by the ceramic substrate welding method with pre-set welding alloy material as claimed in any one of claims 1 to 7, characterized in that: include: Copper-clad ceramic substrates, lead frame terminals, and spherical pre-welding alloy materials; The copper-clad ceramic substrate comprises a ceramic sheet and an oxygen-free copper sheet, wherein the oxygen-free copper sheet covers the upper surface and the lower surface of the ceramic sheet to form the copper-clad ceramic substrate, and a groove is arranged on the upper surface of the copper-clad ceramic substrate to form the spherical pre-set welding alloy material, and the lead frame terminal is welded to the copper-clad ceramic substrate through the spherical pre-set welding alloy material.

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