Method for producing ceramic copper-clad substrate with pins by pre-grooved copper plate

Abstract

The invention relates to a method for producing a ceramic copper-clad substrate with pins by using a pre-grooved copper plate. The method comprises the following steps: placing a copper sheet on an aluminum oxide substrate or an aluminum nitride substrate, and then oxidizing the copper sheet so that cuprous oxide forms on the surface of the copper sheet in contact with air; then opening a pin hole penetrating two side surfaces on the upper surface of the copper sheet, and filling a barrier in the pin hole; turning the copper sheet over and placing it on the aluminum nitride substrate or the aluminum oxide substrate, and a side of the copper sheet with cuprous oxide is bonded to the aluminum nitride substrate or the aluminum oxide substrate for sintering; arranging a plurality of removal areas on the surface of the copper sheet, wherein the removal areas comprise a first removal area and a second removal area, wherein the horizontal cross-sectional projection of the first removal area is located within the horizontal cross-sectional projection of the pin hole, and the second removal area is located between the two first removal areas, and the removal area removes the copper whose horizontal cross-sectional projection on the copper sheet overlaps with the horizontal cross-sectional projection of the removal area, and finally removing the barrier to form a pin. The method can process the pins of the copper sheet without affecting the firmness of the connection between the copper sheet and the aluminum nitride substrate or the aluminum oxide substrate.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum nitride substrates, and in particular relates to a method for producing a ceramic copper-clad substrate with pins from a pre-grooved copper plate. Background Art

[0002] At present, there are two main methods for manufacturing aluminum nitride ceramic-based copper clad laminates: (1) direct bonding copper technology (DBC); (2) direct plating copper technology (DPC).

[0003] The direct copper bonding technology has very strict requirements on the control of process temperature. The temperature must be extremely stable in the range of 1050-1090℃ to melt the surface of the copper layer into a eutectic phase and achieve a close bond with the ceramic substrate.

[0004] DPC is a copper clad laminate manufacturing technology that combines vacuum coating with electroplating technology. Its principle is to first use vacuum coating technology to deposit a copper film on an aluminum oxide or aluminum nitride ceramic substrate, and then use electroplating technology to thicken the copper film. The process temperature of DPC is generally lower than 400°C, which avoids the damage or dimensional variation caused by high temperature to the material. DPC ceramic-based copper clad laminates have the advantages of high heat dissipation, high reliability, high precision and low manufacturing cost. The upper limit of the metal line resolution of DPC ceramic-based copper clad laminates is about 10-50um (based on the aspect ratio of 1:1), and can even be finer, and the surface flatness is high, so it is very suitable for flip chip / eutectic processes that require high line accuracy and high flatness. However, the use of electroplating technology will cause environmental pollution on the one hand, and on the other hand, the bonding force between the copper film plated by electroplating and the ceramic substrate is not very strong, and micropores or holes will be generated during the electroplating process.

[0005] In the prior art, two methods are used to produce aluminum nitride ceramic-based copper-clad laminates, but it is very difficult to open pins on the copper plate. To open the pins, it is necessary to open a pin outlet between the pins and the aluminum nitride ceramic-based copper-clad laminate. The opening process may affect the connection strength between the copper plate and the aluminum nitride ceramic base. In view of this, the present solution was created. Summary of the invention

[0006] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a method for producing a copper-clad aluminum nitride ceramic substrate with pins from a pre-slotted copper plate, which can process the pins of the copper plate without affecting the firmness of the connection between the copper plate and the aluminum nitride substrate.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a basic method for producing aluminum nitride ceramic copper clad with pins from a pre-grooved copper plate, comprising the following steps:

[0008] S1: placing a copper sheet on an aluminum nitride substrate or an aluminum nitride substrate, and then sintering, and cuprous oxide is formed on the surface of the copper sheet in contact with air;

[0009] S2: Then, a pin hole is opened on the upper surface of the copper sheet and passes through two sides, and a barrier is filled in the pin hole;

[0010] S3: Turn the copper sheet over and place it upside down on the aluminum nitride substrate or the aluminum oxide substrate, and the side of the copper sheet with cuprous oxide is bonded to the aluminum nitride substrate for secondary sintering;

[0011] S4: multiple removal areas are set on the surface of the copper sheet, the removal areas include a first removal area and a second removal area, the horizontal section projection of the first removal area is located within the horizontal section projection of the pin hole, the second removal area is located between the two first removal areas, and the copper on the copper sheet whose horizontal section projection overlaps with the horizontal section projection of the removal area is removed, and finally the barrier is removed to form the pin.

[0012] Furthermore, the method for producing aluminum nitride ceramic copper-clad substrate with pins using pre-grooved copper plates also includes step S5: opening an easy-to-break groove on the surface of the aluminum nitride substrate, wherein the horizontal cross-sectional projection of the easy-to-break groove is located within the horizontal plane projection of the pin hole.

[0013] Furthermore, in step S3, there are multiple pin holes, and the multiple pin holes are arranged at equal intervals along the length direction of the copper sheet.

[0014] Furthermore, in step S2, the barrier is solid magnesium oxide.

[0015] Furthermore, in the step S5, laser cutting is used to open an easy-to-break groove on the aluminum nitride substrate or the aluminum oxide substrate.

[0016] Furthermore, in step S4, the copper whose horizontal cross-sectional projection on the copper sheet overlaps with the horizontal cross-sectional projection of the removal area is removed by using a developing and etching process.

[0017] Furthermore, in step S1, the sintering temperature is 450-600 degrees Celsius.

[0018] Furthermore, the sintering temperature in step S2 is 1055-1085 degrees Celsius.

[0019] Furthermore, in step S1, the horizontal cross-sectional projection of the aluminum nitride substrate or the aluminum oxide substrate covers the horizontal cross-sectional projection of the copper sheet.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention places a copper sheet on an aluminum nitride substrate or an aluminum oxide substrate for the first sintering, and a cuprous oxide layer is formed on the surface and the peripheral surface of the copper sheet in contact with air. Then, a plurality of equally spaced pin holes are opened on the upper surface of the copper sheet, and the bottom and side surfaces of the opened pin holes are copper. Then, barriers are filled in the pin holes, and the copper sheet is placed upside down on the aluminum oxide substrate or the aluminum nitride substrate for sintering. The purpose of sintering is to sinter and connect the copper sheet with the aluminum oxide substrate or the aluminum nitride substrate, and to generate a Cu-Cu2O eutectic phase between the side with cuprous oxide and the aluminum nitride substrate at 1070 degrees Celsius, so that the copper sheet and the aluminum nitride substrate are firmly connected together. The purpose of setting the barriers is to prevent the copper sheet above the pin holes from connecting with the aluminum nitride substrate. After sintering is completed, development and etching are performed on the surface of the copper sheet, and the copper in the vertical direction of the first and second areas on the copper sheet is etched away, the copper sheet forms a pin, and the barrier is removed. Cutting is performed from the center line in the width direction of the center line of the pin hole to form an aluminum oxide substrate or aluminum nitride substrate copper-clad sheet with a pin. The method first opens a pin hole before sintering the aluminum oxide substrate or aluminum nitride substrate and the copper sheet, and then uses a barrier to prevent the copper above the pin hole from contacting the ceramic surface during sintering, and then etches away the copper above the pin hole through a development and etching process, thereby directly forming an aluminum oxide substrate or aluminum nitride substrate copper-clad sheet with a pin. Compared with the method of making copper sheet pins in the prior art, it is more reasonable and will not affect the connection firmness between the copper sheet and the aluminum oxide substrate or aluminum nitride substrate.

[0022] 2. The purpose of setting the barrier is to prevent the copper sheet above the pin hole from being connected to the alumina substrate or the aluminum nitride substrate during sintering.

[0023] 3. The purpose of providing the easy-to-break groove is to facilitate breaking the aluminum oxide substrate or aluminum nitride substrate copper-clad sheet with pins into two pieces along the easy-to-break groove when it is used.

[0024] 4. The removal area is removed through the development and etching process, which is more accurate and reasonable, and meets the product manufacturing requirements of copper-clad aluminum oxide substrates or aluminum nitride substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic cross-sectional view of the aluminum nitride substrate and the copper sheet in step S1 of the present invention;

[0026] Figure 2 This is a schematic diagram of the cross-sectional structure of the aluminum nitride substrate and the copper sheet after the pin grooves are opened in step S2 of the present invention;

[0027] Figure 3 This is a schematic diagram of the cross-sectional structure of the aluminum nitride substrate and the copper sheet in step S3 of the present invention;

[0028] Figure 4This is a schematic cross-sectional structural diagram of an aluminum nitride substrate and a copper sheet manufactured in Example 1 of the present invention;

[0029] Figure 5 This is a schematic cross-sectional view of the aluminum nitride substrate and the copper sheet manufactured in Example 2 of the present invention;

[0030] Figure 6 This is a schematic diagram of the cross-sectional structure of the aluminum nitride substrate and the copper sheet after segmentation in Example 1 of the present invention;

[0031] Figure 7 This is a schematic diagram of the cross-sectional structure of the aluminum nitride substrate and the copper sheet after segmentation according to Example 2 of the present invention.

[0032] Markings in the figure: 1. Aluminum nitride substrate; 11. Easy-to-break groove; 2. Copper sheet; 21. Pin hole; 3. First partition channel; 4. Second partition channel; 5. Barrier. DETAILED DESCRIPTION

[0033] In order to make the above features and advantages of the present invention more obvious and easy to understand, embodiments are given below with reference to the accompanying drawings for detailed description as follows. Example

[0034] like Figure 1-4 As shown in Figure 6, this embodiment provides a method for producing a ceramic copper-clad plate with a lead by pre-grooving a copper plate, which includes the following steps:

[0035] This embodiment uses an aluminum nitride substrate 1, step S1: placing a copper sheet 2 on the aluminum nitride substrate 1, specifically, the horizontal cross-sectional projection of the aluminum nitride substrate 1 covers the horizontal cross-sectional projection of the copper sheet 2, and then oxidizing, the sintering temperature is 450-600 degrees Celsius, the oxidation temperature in this embodiment is 460 degrees Celsius, and cuprous oxide is formed on the surface of the copper sheet 2 that contacts the air.

[0036] Step S2: Then, a plurality of pin holes 21 are processed on the upper surface of the copper sheet 2 and are arranged at equal intervals along the length direction of the copper sheet 2, penetrating the pin holes 21 on both sides, and a barrier 5 is filled in the pin holes 21. The barrier 5 is made of a material that is not etched by the etching solution, and specifically, the barrier 5 is magnesium oxide.

[0037] Step S3: Flip the copper sheet 2 and place it upside down on the aluminum nitride substrate 1. The side of the copper sheet 2 with cuprous oxide is bonded to the aluminum nitride substrate 1, that is, the opening of the pin hole 21 of the copper sheet 2 and the barrier 5 are bonded to the aluminum nitride substrate 1, and sintering is performed. The sintering temperature is 1065-1083 degrees Celsius. The second sintering temperature in this embodiment is 1070 degrees Celsius. The purpose of sintering is to connect the side of the copper sheet 2 with copper oxide to the aluminum nitride substrate 1.

[0038] Step S4: multiple removal areas are set on the surface of the copper sheet 2, the removal areas include a first removal area and a second removal area, the horizontal cross-sectional projection of the first removal area is located within the horizontal cross-sectional projection of the pin hole 21, and the second removal area is located between the two first removal areas, and the copper on the copper sheet 2 whose horizontal cross-sectional projection overlaps with the horizontal cross-sectional projection of the removal area is removed, and finally the barrier 5 is removed to form the pin. Specifically, in step S4, a development and etching process is used to remove the copper on the copper sheet 2 whose horizontal cross-sectional projection overlaps with the horizontal cross-sectional projection of the removal area. The specific steps are as follows: first, clean the surface of the copper sheet 2, stick a photosensitive adhesive on the upper surface of the copper sheet 2, then expose the surface of the photosensitive adhesive, cure it after exposure to expose the removal area, then remove the unnecessary photosensitive adhesive layer on the surface, and etch the removal area with an etching solution after drying, remove the first area and etch it to the barrier 5, remove the copper etched in the first area to form a first partition channel 3, remove the second area and etch it until the aluminum nitride substrate 1 can be seen, remove the copper etched in the second area to form a second partition channel 4, the etching solution uses acidic cupric chloride etching solution, alkaline cupric chloride etching solution, etc., and then the residual photosensitive adhesive layer on the surface of the copper sheet 2 is expanded by an acid-base neutralization method, and the excess photosensitive adhesive layer is cleaned with clean water and ultrasonic waves.

[0039] In this embodiment, a copper sheet 2 is placed on an aluminum nitride substrate 1 for oxidation, and cuprous oxide is formed on the surface of the copper sheet 2 in contact with air. A plurality of equally spaced pin holes 21 are formed on the upper surface of the copper sheet 2, and the bottom and side surfaces of the pin holes 21 are copper. Then, a barrier 5 is filled in the pin holes 21. The copper sheet 2 is placed upside down on the aluminum nitride substrate 1 and sintered. The purpose of sintering is to sinter and connect the copper sheet 2 and the aluminum nitride substrate 1 together. At 1070 degrees Celsius, the copper sheet 2 has a side with cuprous oxide and the aluminum nitride substrate 1. A Cu-Cu2O eutectic phase is generated between the plates 1, so that the copper sheet 2 is firmly connected to the aluminum nitride substrate 1. The purpose of setting the barrier 5 is to prevent the copper sheet 2 above the pin hole 21 from being connected to the aluminum nitride substrate 1. After sintering, etching and development are performed on the surface of the copper sheet 2, and the copper in the vertical direction of the first and second areas of the copper sheet 2 is etched away, and the copper sheet 2 is formed with pins. The barrier 5 is removed, and cutting is performed from the center line in the width direction of the center line of the pin hole 21 to form an aluminum nitride substrate 1 copper-clad sheet 2 with pins. Example

[0040] This embodiment uses an aluminum nitride substrate 1, such as Figure 1-3, 5 and 7, the difference between Example 2 and Example 1 is that the sintering temperature of step S1 is 450 degrees Celsius, the sintering temperature of step S3 is 1080 degrees Celsius, and this embodiment also has step S5, step S5 is performed after step S4, step S5: an easy-to-break groove 11 is opened on the lower surface of the aluminum nitride substrate 1, and the horizontal cross-sectional projection of the easy-to-break groove 11 is located within the horizontal plane projection of the pin hole 21. Specifically, the easy-to-break groove 11 is opened on the aluminum nitride substrate by laser cutting. The purpose of setting the easy-to-break groove 11 is to facilitate the copper-clad sheet 2 of the aluminum nitride substrate 1 with pins to be broken into two pieces along the easy-to-break groove 11 when it is used, which is more convenient and quick. Except for the above differences, the rest of the methods are the same.

[0041] In this embodiment, a copper sheet 2 is placed on an aluminum nitride substrate 1 for oxidation, and cuprous oxide is formed on the surface of the copper sheet 2 in contact with air. A plurality of equally spaced pin holes 21 are opened on the upper surface of the copper sheet 2, and the bottom and side surfaces of the opened pin holes 21 are copper. Then, a barrier 5 is filled in the pin holes 21, and the copper sheet 2 is placed upside down on the aluminum nitride substrate 1 for sintering. The purpose of sintering is to sinter and connect the copper sheet 2 and the aluminum nitride substrate 1 together, and to generate a Cu-Cu2O eutectic phase between the side with cuprous oxide and the aluminum nitride substrate 1 at 1070 degrees Celsius, so that the copper sheet 2 2 is firmly connected to the aluminum nitride substrate 1. The purpose of setting the barrier 5 is to prevent the copper sheet 2 above the pin hole 21 from being connected to the aluminum nitride substrate 1. After sintering is completed, etching and development are performed on the surface of the copper sheet 2. The copper in the vertical direction of the first and second areas of the copper sheet 2 is etched away. The barrier 5 is removed, and the copper sheet 2 is formed with a pin. The pin hole 21 is cut from the center line in the width direction of the center line to form the aluminum nitride substrate 1 copper-clad sheet 2 with the pin. Then the aluminum nitride substrate 1 copper-clad sheet 2 is turned over, and then the easy-to-break groove 11 is cut on the surface of the aluminum nitride substrate 1 by a laser cutting machine.

[0042] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for producing a ceramic copper-clad substrate with pins from a pre-grooved copper plate, characterized in that: The following steps are involved: S1: placing a copper sheet on an alumina substrate or an aluminum nitride substrate, and then oxidizing it, so that cuprous oxide forms on the surface of the copper sheet in contact with air; S2: Then, a pin hole is opened on the upper surface of the copper sheet and passes through two sides, and a barrier is filled in the pin hole; S3: turning the copper sheet upside down on the aluminum nitride substrate or the aluminum oxide substrate, and laminating the copper sheet with cuprous oxide on the aluminum nitride substrate or the aluminum oxide substrate for sintering; S4: multiple removal areas are set on the surface of the copper sheet, the removal areas include a first removal area and a second removal area, the horizontal section projection of the first removal area is located within the horizontal section projection of the pin hole, the second removal area is located between the two first removal areas, and the copper on the copper sheet whose horizontal section projection overlaps with the horizontal section projection of the removal area is removed, and finally the barrier is removed to form the pin.

2. The method for producing a ceramic copper-clad substrate with pins from a pre-grooved copper plate according to claim 1, characterized in that: The method for producing a ceramic copper-clad substrate with pins by using a pre-grooved copper plate also includes step S5: S5: an easy-to-break groove is formed on the surface of the aluminum nitride substrate or the aluminum oxide substrate, and the horizontal cross-sectional projection of the easy-to-break groove is located within the horizontal plane projection of the pin hole.

3. The method for producing a ceramic copper-clad substrate with pins from a pre-grooved copper plate according to claim 1, characterized in that: In the step S2, there are multiple pin holes, and the multiple pin holes are arranged at equal intervals along the length direction of the copper sheet.

4. The method for producing a ceramic copper-clad substrate with pins from a pre-grooved copper plate according to claim 1, characterized in that: In step S2, the barrier is solid magnesium oxide.

5. The method for producing a ceramic copper-clad substrate with leads from a pre-grooved copper plate according to claim 2, characterized in that: In the step S5, laser cutting is used to open an easy-to-break groove on the aluminum nitride substrate or the aluminum oxide substrate.

6. The method for producing a ceramic copper-clad substrate with pins from a pre-grooved copper plate according to claim 1, characterized in that: In the step S4, the copper whose horizontal cross-sectional projection on the copper sheet overlaps with the horizontal cross-sectional projection of the removal area is removed by using a developing and etching process.

7. The method for producing a ceramic copper-clad substrate with leads from a pre-grooved copper plate according to claim 1, characterized in that: The oxidation temperature in step S1 is 450-600 degrees Celsius.

8. The method for producing a ceramic copper-clad substrate with leads from a pre-grooved copper plate according to claim 1, characterized in that: The sintering temperature in step S3 is 1065-1085 degrees Celsius.

9. The method for producing a ceramic copper-clad substrate with leads from a pre-grooved copper plate according to claim 1, characterized in that: In the step S1, the horizontal cross-sectional projection of the aluminum nitride substrate or the aluminum oxide substrate covers the horizontal cross-sectional projection of the copper sheet.

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