TW202008862A - Method for improving adhesive force between ceramic carrier board and thick film circuit which can reduce time and processing cost through the ceramic-metal co-crystal layer - Google Patents

Abstract

The invention relates to a method for improving adhesive force between ceramic carrier board and thick film circuit, and more particularly to a method for accelerating the generation of ceramic-metal co-crystal phase by solid-phase diffusion binding between the ceramic carrier board and the meal circuit when the atmosphere is at a positive pressure state. It mainly uses metal conductive slurry or its oxide slurry to print a circuit pattern on a surface of the ceramic carrier board by a thick film screen printing circuit. The carrier board is then placed in an oven with programmable temperature control, and the ambient atmosphere condition is set as a positive pressure inert gas, including nitrogen, hydrogen or nitrogen/hydrogen mixed gas. The co-crystal phase is generated between the ceramic carrier board and the metal circuit after the high-temperature co-crystal condition. Accordingly, the adhesive force between the ceramic carrier board and the thick film circuit can be enhanced.

Description

Method for improving adhesion between ceramic carrier board and thick film circuit

The invention relates to a method for improving the adhesion between a ceramic carrier board and a metal thick-film circuit, in particular to a ceramic-metal eutectic phase produced by solid phase diffusion bonding in a positive pressure atmosphere under high-temperature eutectic conditions with solid-phase diffusion bonding. Improve the adhesion between ceramic carrier board and metal thick film circuit.

Ceramic heat dissipation carrier board has been widely used in various electronic related fields such as various LEDs, power modules and so on. Thick film technology uses screen printed circuits on various types of carrier boards, and then fixed to the ceramic surface by means of LTCC (low temperature co-fired multilayer ceramic) or HTCC (high temperature co-fired multilayer ceramic); as for direct bonding technology (Direct Bonded Copper) is mainly to produce a eutectic phase of copper oxide at the eutectic temperature of the atmosphere between the copper metal circuit and the ceramic substrate, and tightly join the two to improve circuit adhesion.

At present, the connection between the ceramic heat dissipation substrate and the circuit includes DBC, DPC (direct copper plating technology), LTCC, and HTCC metallization processes. Although the DBC process has the advantages of high mechanical strength and other advantages, it still needs to use high-cost process technologies such as yellow light lithography and etching to remove the excess copper foil covered on the surface, as is the DPC technology, and the circuit thickness cannot be greater than 150 μm because of its own process conditions. For high-power applications, there are restrictions; LCTT and HTCC are generally only suitable for the combination of copper circuits and alumina carrier boards because of physical conditions. If aluminum nitride with a higher thermal conductivity is used, the sintering temperature will be much larger Due to the melting point of metallic copper, it is not easy to form circuit patterns.

In order to improve the adhesion between the circuit and the carrier board, the traditional screen printed circuit needs to use an intermediary layer to balance the thermal expansion coefficient of the excessive difference, thereby improving the strength of the circuit, but because of the relationship between the interlayer, the process must still be Consider related steps such as etching or lithography.

Therefore, the industry urgently needs a method that can effectively improve the adhesion between the ceramic carrier and the metal circuit, and reduce the time and process cost.

The object of the present invention is to provide a method for combining thick film screen printing with a ceramic-metal eutectic phase process, which includes a method for improving adhesion.

In view of the shortcomings of the above known technology, the present invention develops a method to improve the adhesion between the metal circuit and the ceramic carrier board, and reduces the time and process cost by the formation of the ceramic-metal eutectic layer.

In order to achieve the above object, according to the solution proposed by the present invention, a process method for improving the adhesion of a ceramic-metal copper circuit is provided. In the first implementation, the method includes providing a ceramic carrier board, which includes a surface that has been screen-thick printed. Circuit pattern of the metal copper oxide layer produced by the membrane technology; surface drying in an oven to remove excess solvent in the metal copper oxide layer; placed in a high-temperature furnace in an atmospheric environment, while adding below 40kgf/cm ² and The pressure in the direction perpendicular to the carrier board; and, setting the temperature of the high-temperature furnace to within ±10°C of the eutectic temperature of the metallic copper and ceramic carrier board, so that a metallic copper-ceramic eutectic layer is generated between the ceramic carrier board and the metallic copper.

In the above, this method can produce a metallic copper-ceramic eutectic layer between the metallic copper and the ceramic carrier board, and use this eutectic layer to improve the adhesion between the metallic copper circuit and the ceramic carrier board to avoid the difference in thermal expansion coefficient or It is easy to cause the peeling of the metal copper circuit and the ceramic carrier board caused by external force; in addition, the use of pressure perpendicular to the direction of the carrier board can improve the efficiency of solid diffusion bonding, and thus help the formation of the metal copper-ceramic eutectic layer.

In the method of the present invention, the steps include: (A) providing a carrier body of ceramic material; (B) cleaning the ceramic carrier board and making it smooth and smooth through polishing and grinding procedures; (C) metal copper or metal The copper oxide prints the circuit pattern on the surface of the ceramic carrier board through the screen printing technology, so that the circuit pattern closely adheres to the surface of the ceramic carrier board; (D) the ceramic carrier board is placed in an oven at a temperature below 105℃ Carry out drying; (E) Put the ceramic carrier plate into an atmosphere of high temperature furnace, and simultaneously apply the pressure below 40kgf/cm ² and perpendicular to the direction of the carrier plate; (F) Set the temperature of the high temperature furnace between metal copper and ceramic The eutectic temperature of the board is within ±10°C, so that a metallic copper-ceramic eutectic layer is generated between the ceramic carrier board and the metallic copper.

The above summary, the following detailed description and the accompanying drawings are intended to further illustrate the ways, means and effects of this creation to achieve its intended purpose. The other purposes and advantages of this creation will be explained in the subsequent description and drawings.

1‧‧‧ cooling fins

2‧‧‧thermal conductive adhesive

3‧‧‧Ceramic carrier board

4‧‧‧Metal circuit

5‧‧‧ solder layer

6‧‧‧Semiconductor components

7‧‧‧Metal copper-ceramic eutectic layer

S101-S106‧‧‧Step

The first figure is a schematic cross-sectional view of the device according to the first embodiment of the present invention.

The second figure is an enlarged explanatory diagram of the joint portion of the metal copper and the ceramic carrier plate in FIG.

The third figure is a schematic flow chart of a method for enhancing the adhesion between a ceramic carrier board and a thick film circuit of the present invention.

The following is a specific example to illustrate the implementation of this creation. Those familiar with this skill can easily understand the advantages and effects of this creation from the content disclosed in this specification.

The existing metallized circuit technology on the ceramic carrier board mostly uses semiconductor processes such as lithography, yellow light, etching, etc., which is not only time-consuming and labor-intensive, but also costly; traditional thick-film technologies such as screen printing are used because of many raw materials. Different characteristics, causing compatibility problems, often cannot adopt a single process technology, and must be matched with composite materials or processes. The present invention develops a method to improve the adhesion between the ceramic carrier board and the thick film circuit, which utilizes the eutectic conditions between the metallic copper and the ceramic carrier board at high temperature to produce a metallic copper-ceramic eutectic layer at the interface, At the same time, the positive pressure perpendicular to the surface of the carrier board is used to improve the generation efficiency of the metal copper-ceramic eutectic layer; the present invention can improve the adhesion of the metal circuit on the ceramic carrier board with one process technology without additional Material or process technology, and can solve the cost of the thin film process applied to the ceramic carrier metallization process, and the problem that aluminum nitride and copper metal cannot be co-fired.

Please refer to the first and second figures, which are cross-sectional views of components according to an embodiment of the present invention.

Referring to the first figure, the semiconductor element 6 is fixed on the metal circuit 4 by using the solder layer 5, and the metal circuit 4 is fixed on the ceramic carrier 3 by the method of improving the adhesion between the ceramic carrier board and the thick film circuit of the present invention. The ceramic carrier board is attached to the back plate of the heat dissipation fin 1 via the thermal conductive adhesive 2.

Please refer to the second figure, using a pressure of 40kgf/cm ² or less and perpendicular to the direction of the ceramic carrier plate 3, while setting it to the eutectic temperature of the metal copper-ceramic with a high-temperature furnace, and performing the solid phase diffusion bonding process to complete the metal copper- The formation of the ceramic eutectic layer 7 further improves the adhesion between the ceramic carrier 3 and the thick film circuit 4.

Please refer to the second figure. This method is applicable to ceramic carrier boards including: aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC) or silicon oxynitride (SiON).

Please refer to the third figure, a flow chart of a method for improving the adhesion between a ceramic carrier board and a thick film circuit of the present invention. As shown in the figure, the present invention provides a method for improving the adhesion between a ceramic carrier board and a thick film circuit. The steps include: (A) providing a body of ceramic carrier board 3 of ceramic material; (B) cleaning the ceramic carrier board 3, and passing Polishing and grinding procedures to make it flat and smooth; (C) Print the circuit pattern on the surface of the ceramic carrier board 3 through the screen printing technology of metal copper or metal copper oxide, so that the metal circuit 4 with the circuit pattern is closely attached On the surface of the ceramic carrier board 3; (D) Put the ceramic carrier board 3 into an oven and dry it at a temperature below 105°C; (E) Put the ceramic carrier board 3 into a high-temperature furnace in an atmospheric environment while Add a pressure below 40kgf/cm ² and perpendicular to the direction of the carrier board; (F) Set the temperature of the high-temperature furnace to within ±10°C of the eutectic temperature of the metal copper and ceramic carrier board 3 so that the ceramic carrier board 3 and the metal circuit 4 The metal copper-ceramic eutectic layer 7 is generated; (G) After the temperature is lowered, the obtained ceramic carrier board 3 can utilize the metal copper-ceramic eutectic layer 7 to improve the adhesion to the metal circuit 4. The thickness of the obtained metallic copper-ceramic eutectic layer can be 2-20 μm.

Above, combined with the traditional screen printed circuit and eutectic layer process technology, combined with the forward pressure and high temperature process, the sandwich sandwich pressure is applied to simultaneously reduce the metal oxide circuit and generate the eutectic layer, and firmly attach the metal circuit On the ceramic carrier board, it solves the waste of time and cost, and at the same time avoids the use of ceramics with low thermal conductivity. In addition, the circuit metallization process of traditional screen-printed ceramic substrates has been refined from a two-step high-temperature process to a simplified process, reducing time cost and overcoming problems such as circuit stripping. In addition, the ceramic material with high thermal conductivity is used at the same time to quickly conduct the waste heat generated by the components, reduce the working temperature and improve the product life.

The ceramic carrier board 3 in this embodiment may be an aluminum-based ceramic carrier board, taking aluminum nitride as an example. In step (B) of the embodiment, after the aluminum nitride ceramic carrier board 3 undergoes a polishing process, the flatness TTV Less than 100μm, the flatness and roughness can be adjusted according to different requirements; in the step (C) of the embodiment, the metal copper or metal copper oxide can be in the form of slurry or glue, mixed evenly with the polymer material, Among them, the metal copper or metal copper oxide accounts for more than 90% of the total weight; in the step (D) of the embodiment, the drying temperature is set below 105° C., and the polymer material in the metal copper or metal copper oxide slurry is vaporized so that The ceramic carrier board 3 is completely bonded to the metal copper or metal copper oxide; in the step (E) of the embodiment, the ceramic carrier board 3 is placed in a high-temperature furnace in an inert atmosphere environment, where the atmosphere may be nitrogen, containing 10% or less Nitrogen in hydrogen or nitrogen containing 30% or less of ammonia; the pressure applied in step (E) of the embodiment can be a positive force perpendicular to the direction of the carrier plate, or the internal pressure of the high-temperature furnace can be increased to 40kgf/cm ² or less; in step (F) of the embodiment, the high-temperature furnace temperature is set within the eutectic temperature of the metallic copper and the ceramic carrier board 3 within ±10°C. The ceramic carrier board material used in this embodiment is aluminum nitride ceramic, aluminum series The eutectic temperature of ceramic and metallic copper is 1065℃, so the high temperature eutectic temperature set by this implementation force is within 1065℃±10℃, that is, the metallic copper produced between the aluminum-based ceramic carrier plate 3 and the metallic copper- Ceramic eutectic layer 7 (AlN-Al ₂ O ₃ -Cu). After the steps of this embodiment are completed, a metallized ceramic carrier board with high adhesion can be obtained.

In summary, in the present invention, after metal or metal oxide is screen printed on the ceramic substrate, when the metal oxide is reduced at a high temperature, a strong eutectic phase interface can be formed at the eutectic temperature of ceramic and metal, and cooperate with the positive force Pressurization, at the same time complete the metallized ceramic carrier board process and strengthen the circuit adhesion, simplify the process, reduce equipment and labor costs, and at the same time improve the heat transfer efficiency, so that the waste heat of high-power modules or 3C components can quickly cool down and extend the life of the component And improve reliability. In addition, the present invention is based on the metal-ceramic eutectic theory, and with the forward pressure, at the eutectic temperature of the metal and ceramic (adding a small amount of O ₂ ), it produces a strong and powerful eutectic interface to overcome the difference in thermal expansion coefficient, etc. Process issues. In addition, compared with DBC or DPC, this method requires the use of yellow light lithography and other process technologies, which can greatly reduce equipment and labor costs, and because the process temperature is low (1065~1085℃), high thermal conductivity aluminum nitride ceramics can be used. Board material (and alumina for LCTT and HTCC).

The above-mentioned embodiments are only illustrative of the characteristics and effects of this creation, and are not intended to limit the scope of the substantive technical content of this creation. Anyone who is familiar with this skill can modify and change the above embodiments without violating the spirit and scope of creation. Therefore, the scope of protection of the rights of this creation should be as listed below in the scope of patent application.

1‧‧‧ cooling fins

2‧‧‧thermal conductive adhesive

3‧‧‧Ceramic carrier board

4‧‧‧Metal circuit

5‧‧‧ solder layer

6‧‧‧Semiconductor components

Claims (9)

A method for improving the adhesion between a ceramic carrier board and a thick film circuit, the steps include: (A) providing a ceramic carrier board body of one of ceramic materials; (B) cleaning the ceramic carrier board, and smoothing it through polishing and grinding procedures Smooth; (C) print a circuit pattern on the surface of the ceramic carrier board through a screen printing technique of a metal copper or a metal copper oxide, so that a metal circuit closely adheres to the surface of the ceramic carrier board; (D) Place the ceramic carrier plate in an oven and dry it at a temperature below 105°C; (E) Place the ceramic carrier plate in a high-temperature furnace in an atmospheric environment, and simultaneously apply a pressure of 40 kgf/cm ² or less and perpendicular to the direction of the carrier plate (F) Set a high-temperature furnace temperature within ±10°C of the eutectic temperature of the metallic copper and the ceramic carrier board, so that a metallic copper-ceramic eutectic layer is generated between the ceramic carrier board and the metal circuit; (G ) After the temperature is lowered, the obtained ceramic carrier board utilizes the metal copper-ceramic eutectic layer to improve the adhesion to the metal circuit. The method for improving the adhesion between a ceramic carrier board and a thick film circuit as described in item 1 of the patent application scope, wherein the ceramic carrier board includes aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), and silicon nitride ( Si ₃ N ₄ ), silicon carbide (SiC) or silicon oxynitride (SiON). The method for improving the adhesion between the ceramic carrier board and the thick film circuit as described in item 1 of the patent application scope, wherein after the ceramic carrier board is polished and polished, the flatness TTV is less than 100 μm, and the flatness and roughness are performed according to different needs Adjustment. 3. The method for improving the adhesion between a ceramic carrier board and a thick film circuit as described in item 1 of the patent application scope, wherein the metallic copper or the metallic copper oxide is in the form of a paste or a glue, and a The polymer materials are mixed evenly, wherein the metallic copper or the metallic copper oxide accounts for more than 90% of the total weight. The method for improving the adhesion between a ceramic carrier board and a thick film circuit as described in item 3 of the patent application scope, wherein in step (D), the polymer material in the slurry or the compound is vaporized, The ceramic carrier board and the metal circuit are completely attached. The method for improving the adhesion between a ceramic carrier board and a thick film circuit as described in item 1 of the patent application scope, wherein the atmosphere is nitrogen, nitrogen containing 10% or less of hydrogen, or nitrogen containing 30% or less of ammonia. The method for improving the adhesion between the ceramic carrier board and the thick film circuit as described in item 1 of the patent application scope, wherein the pressure applied in the high-temperature furnace adopts a positive force perpendicular to the direction of the carrier board, or increases the inside of the high-temperature furnace The air pressure is below 40kgf/cm ² . The method for improving the adhesion between a ceramic carrier board and a thick film circuit as described in item 1 of the patent scope, wherein the ceramic carrier board is an aluminum-based ceramic carrier board, and the high-temperature furnace temperature is set between the metallic copper and the aluminum-based system The eutectic temperature of the ceramic carrier board is within 1065℃±10℃. The method for improving the adhesion between a ceramic carrier board and a thick film circuit as described in item 7 of the patent application scope, wherein the obtained metallic copper-ceramic eutectic layer is AlN-Al ₂ O ₃ -Cu. The method for improving the adhesion between a ceramic carrier board and a thick film circuit as described in item 1 of the patent application scope, wherein the thickness of the metallic copper-ceramic eutectic layer is 2-20 μm.

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