TWI512150B - Preparation of copper - clad copper - clad copper clad copper - Google Patents

Description

Method for preparing thick copper copper clad on aluminum nitride substrate

The invention relates to a method for preparing a thick copper copper-clad of an aluminum nitride substrate, in particular to a method of depositing a copper film on a silicon nitride substrate by sputtering a metal such as titanium or tungsten on the aluminum nitride substrate, and performing an oxygen-free copper thick copper process. The use of metals such as titanium and tungsten allows the copper circuit to have good compatibility with the aluminum nitride substrate.

Conventionally, LED products have energy saving, high efficiency, long service life, and no toxic substances. However, 80% of the input power of LED products will be lost due to thermal energy. Solving the LED cooling system is currently the most important issue. LED heat dissipation methods mainly include (1) direct heat dissipation from the air (2) die heat dissipation substrate to conduct heat to the system circuit board (3) electrode metal wires conduct heat to the system circuit board.

According to the method for manufacturing a copper-plated ceramic substrate, as described in American Ceramic Society Journal 61, 1978, by AK Varchneya and RJ Petti, a copper plate or a copper film is directly bonded to a ceramic substrate; or silver, gold, copper, and nickel. Applying to a ceramic substrate by printing or other methods, directly performing plating or heating for several hundred degrees, and then performing plating, but the copper particles precipitated by the electroless copper plating mentioned above have a large particle size and a contact area with an irregular portion of the surface of the ceramic substrate. Small, the adhesion between the copper particles and the ceramic substrate is poor, and an organic compound is required as an adhesive. The compound is easily cracked and the bonding strength is lowered. The invention patent of the Republic of China No. 528814 proposes a copper-plated ceramic substrate for a semiconductor. The patent has a thin film chromium layer on the ceramic substrate layer and a thin film gold layer on the chromium layer, wherein the gold layer is plated with copper, and another metal layer is formed between the gold layer and the chromium layer to enhance adhesion, by the gold layer and The chrome layer enhances the adhesion between the ceramic layer and the copper layer, and the multi-layer metal-assisted copper layer is attached to the ceramic substrate, which is relatively expensive and has many processes. Patent No. I238452 of the Republic of China, in order to solve the problem of leakage current caused by copper diffusion between metal wires, and to provide aluminum diffusion as a copper diffusion preventing film, in order to solve the problem of leakage current caused by copper diffusion between metal wires. a method of forming, after deposition in a thin aluminum film, then the upper surface of the aluminum plasma processing performed by NH _3, converted to a nitride film of aluminum nitride (Al _x N _y) as the backbone, and then The aluminum film is vapor-deposited on the surface of the nitride film, and copper is vapor-deposited on the vapor-deposited surface film to suppress the diffusion of copper. The plasma is vapor-deposited as a multi-channel film to prevent copper wire diffusion, and the process is complicated. It does not solve the problem of leakage current caused by suppressing copper diffusion on the ceramic substrate. Further, as described in the Republic of China invention patent TW201134328A1, a nickel metal layer is formed on the surface of the ceramic substrate by a sputtering process, the copper metal layer is coated on the nickel metal layer, and the copper metal layer is etched away to form a ceramic. Copper plated substrate.

The heat generated by the LED is mainly transmitted from the LED die substrate to the system circuit board, and the LED die substrate is the medium between the die and the system circuit board, and the substrate material is the ceramic substrate mainly according to the circuit preparation method, and the low temperature co-fired multilayer ceramic is different. LTCC (Low-Temperature Co-fired Ceramic), High-Temperature Co-fired Ceramic (HTCC), Direct Bonded Copper (DBC) and Direct Copper Plated (DPC, Direct) Plate Copper), LTCC added glass material to reduce the overall thermal conductivity to 2~3W/mK, which is lower than other ceramic substrates. LTCC and HTCC all use screen printing to print the circuit, so that the line itself has insufficient wire diameter. Fine, and screen-laid network problems, resulting in insufficient line accuracy, poor surface flatness, etc., plus multi-layer pressure sintering and substrate shrinkage ratio issues need to be considered, DBC copper layer and ceramic substrate adhesion, The use of high temperature melting at 1065 ° C ~ 1085 ° C, high manufacturing costs, and the problem of micro-pores between the substrate and the copper plate is not easy to solve, DPC film process vacuum sputtering method is coated with thin copper, and then yellow light Line lithography process is completed, 10 ~ 50μm, diameter wider than the application level suitable for high-power and small size of the LED. In summary, the improvement of the adhesion between the ceramic substrate and the metal, and the improvement of the accuracy of the wiring on the substrate are still the problems to be solved.

In view of the above disadvantages of the prior art, the present invention provides a method for preparing a thick copper copper-clad of an aluminum nitride substrate by sputtering a titanium or tungsten metal on the surface of an aluminum nitride substrate, and then depositing a layer of titanium or tungsten. Electroplating a copper layer and covering the electroplated copper layer with an oxygen-free copper thick plate to perform a sintering process, and using a metal such as titanium or tungsten to make the copper circuit and the aluminum nitride substrate have better compatibility, and The aluminum nitride substrate is used as the heat dissipation substrate to improve the heat dissipation efficiency of the LED circuit board.

The object of the present invention is to disclose a method for preparing a copper-clad copper-clad copper-clad substrate, which is first prepared by plating titanium or tungsten metal and copper layers on the aluminum nitride substrate before sintering, and plating the copper film to make two upper and lower substrates Can be joined together by the mutual diffusion of copper. The plated copper substrate and the aluminum nitride substrate are stacked and placed in a high temperature furnace for sintering, and the copper grain is grown to an aluminum nitride substrate by a sintering mechanism, and the thick copper substrate is combined with the aluminum nitride to complete the copper-coated aluminum nitride substrate. . Since no direct needle is applied to the copper ceramic substrate The composition of the solder, thus reducing the solder layer, reducing the thermal resistance, reducing the hole, improving the yield, and the line width of the 0.3mm thick copper foil at the same current carrying capacity is only 10% of the ordinary printed circuit board. The oxygen-free copper substrate has a purity of 99.99%, an oxygen content of less than 10 ppm, and the remaining impurities are less than 50 ppm. However, the general copper plate containing oxygen and other impurities may affect the electrical and mechanical properties of the sintered circuit board.

Another object of the present invention is a method for preparing a copper-clad copper-clad copper-clad substrate, the method comprising the steps of: providing an aluminum nitride substrate; forming a titanium or tungsten on the surface of the aluminum nitride substrate by using a sputtering process a metal layer; forming a copper metal on the titanium or tungsten metal layer by electroplating to form a composite substrate; providing an oxygen-free copper thick plate; bonding one side of the oxygen-free copper thick plate to the composite substrate; The substrate is placed in an atmosphere high temperature furnace, and the sintering process temperature is set to 900 to 1050 ° C, and the chamber is filled with nitrogen to isolate the air. The other side of the oxygen-free copper thick plate may be combined with the composite substrate, wherein the titanium or tungsten metal may be pure titanium metal, pure tungsten metal, titanium alloy or tungsten alloy.

The above summary and the following detailed description are intended to further illustrate the manner, means and function of the present invention to achieve the intended purpose. Other objects and advantages of the present invention will be set forth in the description which follows.

S11~S16‧‧‧Steps

S21~S26‧‧‧Steps

11‧‧‧Aluminum nitride

12‧‧‧Titanium

13‧‧‧Electroplated copper layer

14‧‧‧Oxygen-free copper plate

21‧‧‧Aluminum nitride

22‧‧‧Tungsten metal

23‧‧‧Electroplated copper layer

24‧‧‧Oxygen-free copper plate

25‧‧‧Electroplated copper layer

26‧‧‧Titanium

27‧‧‧Aluminum nitride

The first figure is a flowchart of Embodiment 1 of the present invention.

The second figure is a schematic structural view of the first embodiment of the present invention.

The third figure is a flowchart of the second embodiment of the present invention.

The fourth figure is a schematic structural view of the second embodiment of the present invention.

The embodiments of the present invention are described below by way of specific examples, and those skilled in the art can readily appreciate the other advantages and advantages of the present invention.

Embodiment 1

Please refer to the flow chart of the first embodiment of the present invention, a method for preparing a thick copper copper-clad of an aluminum nitride substrate, the method comprising the steps of: providing an aluminum nitride substrate S11; forming a surface of the aluminum nitride substrate by using a sputtering process a titanium or tungsten metal layer S12; forming a copper metal on the titanium or tungsten metal layer by electroplating to form a composite substrate S13; providing an oxygen-free copper plate S14; and etching the one side of the oxygen-free copper plate The composite substrate is combined with S15; the bonded substrate is placed in an atmosphere high temperature furnace to perform a sintering process S16. Formed by this embodiment The thick copper-clad structure of the aluminum nitride substrate is as shown in the second figure. In the figure, the aluminum nitride 11 is a substrate of 1 to 2 μm pure titanium metal 12 on the aluminum nitride 11 substrate, and 20 on the pure titanium metal. The 28μm electroplated copper layer 13 is finally overlaid on the electroplated copper layer 13 with a 0.4-0.7 mm oxygen-free copper plate 14 to form a thick copper-copper structure of an aluminum nitride substrate.

Embodiment 2

Please refer to the flow chart of the third embodiment of the present invention, another method for preparing a thick copper copper-clad of an aluminum nitride substrate, the method comprising the steps of: providing an aluminum nitride substrate S21; and using a sputtering process on the surface of the aluminum nitride substrate Forming a titanium or tungsten metal layer S22; forming a copper metal on the titanium or tungsten metal layer by electroplating to form a composite substrate S23; providing an oxygen-free copper plate S24; and respectively forming the two sides of the oxygen-free copper plate S25 is combined with the composite substrate; the bonded substrate is placed in an atmosphere high temperature furnace, and a sintering process S26 is performed. The thick copper-copper-clad structure of the aluminum nitride substrate formed by the embodiment is as shown in the fourth figure, wherein the aluminum nitride 21 is a substrate on the aluminum nitride 21 substrate, which is 1 to 2 μm pure tungsten metal 22, pure tungsten. The metal is 20~28μm electroplated copper layer 23, and the first aluminum nitride composite material is combined with one side of 0.4-0.7mm oxygen-free copper thick plate 24, and further comprises electroplated copper layer 25, pure titanium metal 26 and nitrogen. The second aluminum nitride composite material of the aluminum alloy 27, wherein the electroplated copper layer 25 is combined with the other side of the oxygen-free copper thick plate 24, forms another thick aluminum-clad copper-clad structure of the aluminum nitride substrate.

The above-described embodiments are merely illustrative of the features and functions of the present invention and are not intended to limit the scope of the technical scope of the present invention. Modifications and variations of the above-described embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be as set forth in the scope of the claims described below.

S11~S16‧‧‧Steps

Claims (9)

A method for preparing a thick copper copper-clad of an aluminum nitride substrate, the method comprising the steps of: (A) providing an aluminum nitride substrate; (B) forming a titanium or tungsten metal on the surface of the aluminum nitride substrate by a sputtering process (C) electroplating copper metal on the titanium or tungsten metal layer to form a composite substrate; (D) providing an oxygen-free copper thick plate; (E) one side of the oxygen-free copper thick plate The composite substrate is combined; (F) the substrate combined with the step (E) is placed in an atmosphere high-temperature furnace, the atmosphere of the furnace is nitrogen, and the sintering process is performed at a temperature ranging from 900 to 1050 °C. The method for preparing a copper-clad thick copper clad copper according to claim 1, wherein the titanium metal layer of the step (B) is pure titanium or titanium alloy metal. The method for preparing a thick copper copper-clad of an aluminum nitride substrate according to the first aspect of the invention, wherein the tungsten metal layer of the step (B) is a pure tungsten or a tungsten alloy metal. The method for preparing a copper-clad thick copper clad copper according to the first aspect of the invention, wherein the thickness of the titanium or tungsten metal layer of the step (B) is 1 to 2 μm. The method for preparing a copper-clad thick copper clad copper according to the first aspect of the invention, wherein the copper metal layer of the step (C) has a thickness of 20 to 28 μm. The method for preparing a copper-clad thick copper clad copper according to the first aspect of the invention, wherein the thickness of the oxygen-free copper thick plate of the step (D) is 0.4 to 0.7 mm. The method for preparing a copper-clad thick copper clad copper according to claim 1, wherein the step (E) further bonds the other side of the oxygen-free copper thick plate to the composite substrate. The method for preparing a copper-clad thick copper clad copper according to claim 1, wherein the step (F) atmosphere high temperature furnace is under a nitrogen atmosphere. The method for preparing a copper-clad thick copper clad copper according to claim 1, wherein the sintering process temperature of the step (F) atmosphere high-temperature furnace is 900-1050 °C.