Ceramic substrate copper coating method

Abstract

The invention relates to the field of copper-clad plate preparation processes, in particular to a ceramic substrate copper-clad method for improving the peel strength of a ceramic copper-clad plate, which comprises the following steps of: a, trepanning a ceramic substrate; b, printing and hole filling are conducted, specifically, a hole filling printing screen is customized according to the hole positions and sizes of the mark holes and the product via holes, the mark holes of the hole filling printing screen and the mark holes of the ceramic substrate are arranged in a one-to-one correspondence mode, printing patterns of the hole filling printing screen and the product via holes are arranged in a one-to-one correspondence mode, and then hole filling slurry is printed to the product via holes through the hole filling printing screen; c, the baking process comprises the following parameters: the baking temperature is 100-450 DEG C; the baking time is 20 to 60 minutes; the baking atmosphere is oxidizing atmosphere, vacuum atmosphere or nitrogen atmosphere; d, the copper-clad brazing process comprises the steps that the brazing atmosphere is vacuum atmosphere, and the vacuum degree ranges from 10 <-1 > Pa to 10 <-5 > Pa; the brazing temperature ranges from 500 DEG C to 1000 DEG C; the production efficiency is 500-2000 pieces per furnace, the time consumed by each furnace is 10-20 H, and then copper-clad brazing is completed. The method is particularly suitable for the preparation process of the ceramic copper-clad plate.

Description

Technical Field

[0001] The invention relates to the field of copper clad plate preparation technology, in particular to a ceramic substrate copper cladding method. Background Art

[0002] IGBT, also known as diode-bridge power module, is widely used in household appliances, rail transit, power engineering, renewable energy and smart grid. It has good high voltage resistance and thermal conductivity. In IGBT power module, ceramic copper clad laminate is an important component. The ceramic substrate of ceramic copper clad laminate has the characteristics of high thermal conductivity, good heat resistance, low thermal expansion coefficient, high mechanical strength, good insulation, corrosion resistance and radiation resistance, and is widely used in electronic device packaging.

[0003] The existing preparation process of ceramic copper-clad laminates is mainly achieved by conducting, filling holes and coating copper on ceramic substrates, including PVD sputtering, electroplating hole filling, and full-surface electroplating copper related processes. The existing problems in the field of copper-clad laminates are as follows: 1. The peel strength of the obtained copper-clad laminate products is low (generally less than 10N / mm), which is difficult to meet customer needs; 2. During the preparation process, the efficiency of electroplating hole filling and full-surface thick copper plating is low; 3. After the full-surface thick copper plating, traces are left on the openings of the substrate, which need to be processed in subsequent processes. In short, the existing electroplating hole filling copper plating process has defects in performance, and the full-surface thick copper plating is inefficient and costly. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a ceramic substrate copper cladding method which can effectively improve the peeling strength of the ceramic copper clad plate.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a method for copper coating a ceramic substrate, comprising the following steps: a. opening a hole in a ceramic substrate: setting mark holes at the four corners of a rectangular ceramic substrate, and setting a product via hole in the punching area in the middle of the rectangular ceramic substrate; b. printing and filling holes: customizing a hole-filling printing screen according to the hole positions and sizes of the mark holes and the product via holes, the mark holes of the hole-filling printing screen are set one-to-one with the mark holes of the ceramic substrate, the printed pattern of the hole-filling printing screen is set one-to-one with the product via holes, and then the hole-filling slurry is printed on the product via holes through the hole-filling printing screen; c. the baking process includes the following parameters, baking temperature: 100 to 450°C; baking time: 20 to 60min; baking atmosphere: oxidizing atmosphere, vacuum atmosphere or nitrogen atmosphere; d. the copper-clad brazing process includes: the brazing atmosphere is a vacuum atmosphere, and the vacuum degree is 10 -1 Up to 10 -5 Pa; brazing temperature 500 to 1000℃; production efficiency: 500-2000 pieces / furnace, each furnace takes 10-20 hours, and then the copper cladding brazing process is completed.

[0006] Furthermore, in step a, fiber laser cutting is used to open the hole, the diameter of the mark hole is 0.5mm to 2.0mm, the diameter of the product via hole is 0.1mm to 0.8mm, and the thickness of the ceramic substrate is 0.2mm to 0.76mm.

[0007] Furthermore, in step a, the laser energy of the fiber laser is in the range of 20-80%, the scribing speed of the fiber laser is 5 to 80 mm / s, and the duty cycle is in the range of 10-35%.

[0008] Furthermore, in step b, the hole-filling slurry includes Cu, Ag, Ti, Al, W and Mn, and the solid content of the hole-filling slurry ranges from 50% to 90%.

[0009] Furthermore, in step b, the method for making the printed filling hole is: first, the mark hole of the ceramic substrate is identified by the CCD visual alignment method, and then the mark hole of the filling hole printing screen is aligned with the mark hole of the ceramic substrate, and then the filling hole slurry is printed into the product conductive hole through the filling hole printing screen.

[0010] Furthermore, in step b, the printing parameters of the hole-filling printing screen include: the screen mesh number is 100 to 700 meshes, the printing pressure is 0.1 to 0.4 MPa, and the number of printing times is 1 to 5 times.

[0011] Furthermore, the ceramic substrate includes alumina, beryllium oxide, toughened alumina, silicon nitride and aluminum nitride.

[0012] Furthermore, in step d, the copper cladding brazing process includes double-sided copper cladding or single-sided copper cladding.

[0013] The beneficial effects of the present invention are as follows: the ceramic copper-clad laminate prepared by the present solution meets the requirement of void detection standard ≤1%, and at the same time, the average value of peel strength measurement can reach 25N / mm, and can also meet the requirement of no bulging and void abnormality after high temperature resistance and hot and cold shock test. The present invention is particularly suitable for the preparation process of ceramic copper-clad laminates. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of setting mark holes on the ceramic substrate of the present invention and setting product via holes in the punching area.

[0015] Marked in the figure: mark hole 1, punching area 2, ceramic substrate 3. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0017] The copper-clad method of the ceramic substrate mainly includes four steps: opening a hole in the ceramic substrate 3, printing and filling the hole, baking and copper-clad brazing. Figure 1 As shown, it is a hole-opening scheme of a rectangular ceramic substrate 3. Among them, mark holes 1 are set at the four corners of the ceramic substrate 3. Specifically, the mark holes at the upper left corner, the upper right corner and the lower right corner are designed with two holes, and the mark hole 1 at the lower left corner is designed with three holes, so as to realize the front and back identification of the product. A punching area 2 is set in the middle part of the rectangular ceramic substrate 3, and a product via hole is set in the punching area 2. When opening the hole, fiber laser cutting is used to open the hole. The aperture of the mark hole 1 is 0.5mm to 2.0mm, the aperture of the product via hole is 0.1mm to 0.8mm, and the thickness of the ceramic substrate 3 is 0.2mm to 0.76mm. The laser energy range of the fiber laser is 20-80%, the scribing speed of the fiber laser is 5 to 80mm / s, and the duty cycle range is 10-35%. The ceramic substrate 3 includes aluminum oxide, beryllium oxide, toughened aluminum oxide, silicon nitride and aluminum nitride.

[0018] The following is the printing and filling process: the filling printing screen is customized according to the hole position and size of the mark hole 1 and the product conductive hole, the mark hole of the filling printing screen is set in a one-to-one correspondence with the mark hole 1 of the ceramic substrate 3, the printing pattern of the filling printing screen is set in a one-to-one correspondence with the product conductive hole, and then the filling slurry is printed on the product conductive hole through the filling printing screen. The filling slurry includes Cu, Ag, Ti, Al, W and Mn, and the solid content of the filling slurry ranges from 50% to 90%. The production method of the printing filling is: first, the mark hole (1) of the ceramic substrate (3) is identified by the CCD visual alignment method, and then the mark hole of the filling printing screen is aligned with the mark hole (1) of the ceramic substrate (3), and then the filling slurry is printed on the product conductive hole through the filling printing screen. The printing parameters of the filling printing screen include: the screen mesh is 100 to 700 mesh, the printing pressure is 0.1 to 0.4Mpa, and the number of printings is 1 to 5 times. This process can effectively improve the effect of printing the filling paste into the product's conductive holes, thereby providing a structural basis for subsequently improving the peel strength.

[0019] The baking process is used to solidify the hole filling slurry. The baking process includes the following parameters: baking temperature: 100 to 450°C; baking time: 20 to 60 minutes; baking atmosphere: oxidizing atmosphere, vacuum atmosphere or nitrogen atmosphere. Subsequently, the copper cladding brazing process is carried out. The copper cladding brazing process includes: the brazing atmosphere is a vacuum atmosphere, and the vacuum degree is 10 -1 Up to 10 -5Pa; brazing temperature 500 to 1000℃; production efficiency: 500-2000 pieces / furnace, each furnace takes 10-20 hours, and then the copper clad brazing process is completed to obtain a ceramic copper clad board. Based on the previous printing and filling process, this baking process and copper clad brazing process ensure that the peel strength is finally improved.

[0020] After testing the performance of the obtained ceramic copper clad laminate, the following data were obtained:

[0021] 1. Ultrascan void detection: meets void detection standards ≤1%.

[0022] 2. Peel strength test: The average peel strength measurement is 25N / mm.

[0023] sample 1 2 3 average value Peel strength 26.7 24.4 23.9 25

[0024] 3. High temperature resistance and hot and cold shock test: no abnormal bulging and voids.

[0025] It can be seen from the above scheme and test data that the peel strength of the ceramic copper clad laminate obtained by this scheme is significantly improved, and the corresponding void detection standards and high temperature resistance and thermal shock detection standards are up to standard.

Claims

1. A method for copper coating a ceramic substrate, characterized in that: The steps include: a. Opening holes in the ceramic substrate (3): setting mark holes (1) at the four corners of the rectangular ceramic substrate (3), and setting product conducting holes in the punching area (2) in the middle of the rectangular ceramic substrate (3); b. Printing and filling holes: a hole-filling printing screen is customized according to the hole positions and sizes of the mark holes (1) and the product conductive holes, the mark holes of the hole-filling printing screen are arranged in a one-to-one correspondence with the mark holes (1) of the ceramic substrate (3), and the printing patterns of the hole-filling printing screen are arranged in a one-to-one correspondence with the product conductive holes, and then the hole-filling slurry is printed on the product conductive holes through the hole-filling printing screen; c. The baking process includes the following parameters: baking temperature: 100 to 450°C; baking time: 20 to 60 minutes; baking atmosphere: oxidizing atmosphere, vacuum atmosphere or nitrogen atmosphere; d. Copper clad brazing process includes: Brazing atmosphere is vacuum atmosphere, vacuum degree: 10 -1 Up to 10 -5 Pa; brazing temperature 500 to 1000℃; production efficiency: 500-2000 pieces / furnace, each furnace takes 10-20 hours, and then the copper cladding brazing process is completed.

2. The method for copper coating a ceramic substrate according to claim 1, wherein: In step a, fiber laser cutting is used to open the holes, the diameter of the mark hole (1) is 0.5 mm to 2.0 mm, the diameter of the product via hole is 0.1 mm to 0.8 mm, and the thickness of the ceramic substrate (3) is 0.2 mm to 0.76 mm.

3. The method for copper coating a ceramic substrate according to claim 2, wherein: In step a, the laser energy of the fiber laser is in the range of 20-80%, the scribing speed of the fiber laser is 5 to 80 mm / s, and the duty cycle is in the range of 10-35%.

4. The method for copper coating a ceramic substrate according to any one of claims 1 to 3, characterized in that: In step b, the hole filling slurry includes Cu, Ag, Ti, Al, W and Mn, and the solid content of the hole filling slurry ranges from 50% to 90%.

5. The method for copper coating a ceramic substrate according to claim 4, characterized in that: In step b, the method for making the printed hole filling is as follows: first, the mark hole (1) of the ceramic substrate (3) is identified by a CCD visual alignment method, and then the mark hole of the hole filling printing screen is aligned with the mark hole (1) of the ceramic substrate (3), and then the hole filling slurry is printed on the product conductive hole through the hole filling printing screen.

6. The method for copper coating a ceramic substrate according to claim 5, characterized in that: In step b, the printing parameters of the hole filling printing screen include: the screen mesh number is 100 to 700 meshes, the printing pressure is 0.1 to 0.4 MPa, and the number of printing times is 1 to 5 times.

7. The method for copper coating a ceramic substrate according to any one of claims 1 to 3, characterized in that: The ceramic substrate (3) comprises alumina, beryllium oxide, toughened alumina, silicon nitride and aluminum nitride.

8. The method for copper coating a ceramic substrate according to any one of claims 1 to 3, characterized in that: In step d, the copper cladding brazing process includes double-sided copper cladding or single-sided copper cladding.

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