CN-116230564-B - Low-temperature sintering connection method for nano copper material

Abstract

The invention provides a low-temperature sintering connection method of a nano copper material, which comprises the steps of sintering in a catalyzed formic acid gas atmosphere, heating to 80-200 ℃ in the sintering process, preserving heat for 5-10min, and continuously sintering for 3-30min under the conditions of 0-30MPa of pressure and 0-280 ℃, wherein the formic acid gas is catalyzed by a catalyst film loaded on the surface of a porous heating ceramic plate. The method utilizes the catalyst in the form of nano film to catalyze the formic acid, and performs low-temperature sintering connection on the nano copper material under a specific sintering process window, so that the problems of weak mechanical property and poor electrical property of the nano copper material can be solved, and the sintering connection method has the advantages of remarkable reduction effect, economy, environmental protection and high efficiency.

Inventors

• JIA QIANG
• HU HUAN
• GUO FU
• CUI ZE
• WANG YISHU
• MA LIMIN

Assignees

• 北京工业大学

Dates

Publication Date

20260505

Application Date

20230118

Claims (11)

1. 1. The low-temperature sintering connection method of the nano copper material is characterized by comprising the steps of sintering in a catalyzed formic acid gas atmosphere, heating to 80-200 ℃ in the sintering process, preserving heat for 5-10min, and continuing sintering for 3-30min under the conditions of 0-30MPa of pressure and 0-280 ℃; wherein the formic acid gas is catalyzed by a catalyst film supported on the surface of the porous heated ceramic sheet.
2. 2. The low-temperature sintering connection method of the nano copper material according to claim 1, wherein the catalyst film is a Pt nano film or a Pd nano film, and the catalyst film is loaded on the surface of the porous heating ceramic plate through pulse laser deposition.
3. 3. The method for low-temperature sintering connection of nano-copper material according to claim 2, wherein the thickness of the porous heating ceramic sheet is 2-50mm, and the thickness of the catalyst thin film is 10-1000 μm.
4. 4. The method for low-temperature sintering connection of nano copper material according to claim 2, wherein the diameter of the holes on the porous heating ceramic plate is 0.1-5mm, and the catalytic temperature of the porous heating ceramic plate is controlled to be 100-300 ℃.
5. 5. The method for low-temperature sintering connection of nano copper material according to claim 4, wherein the holes on the porous heating ceramic plates are intensively distributed in a half area of the porous heating ceramic plates, and 2-10 porous heating ceramic plates loaded with catalyst films are adopted in the process of catalyzing formic acid gas, and the phase difference between every two adjacent porous heating ceramic plates is 180 degrees, so that the holes are arranged in a staggered manner.
6. 6. The method according to any one of claims 1 to 5, wherein the nano copper material is copper paste, a layer of copper paste is coated on the lower substrate before sintering, the lower substrate is heated at 80 to 200 ℃ for 5 to 15min in the atmosphere, and then a second layer of copper paste is coated on the lower substrate, so that the adhesion of the copper paste to the chip during sintering is ensured.
7. 7. The method of low temperature sintering joining of nano copper material according to claim 6, wherein the first layer of copper paste has a thickness ranging from 150 to 200 μm and the second layer of copper paste has a thickness ranging from 50 to 100 μm.
8. 8. The method for joining nano-copper materials by low temperature sintering according to any one of claims 1 to 5, wherein after sintering is completed, the material is cooled in a nitrogen atmosphere until the temperature is lowered to 100 ℃ or lower.
9. 9. Use of the low temperature sintering connection method of nano copper material according to any one of claims 1-8 in the preparation of power semiconductors.
10. 10. The catalytic device manufactured by the sintering connection method according to any one of claims 1 to 8, comprising a shell and porous heating ceramic plates arranged in the shell, wherein the number of the porous heating ceramic plates is 2 to 10, each plate is vertically and parallelly arranged, the edge of each plate is attached to the inner wall of the shell, a half area of each porous heating ceramic plate is provided with holes, the diameter of each hole is 0.1 to 5mm, the phase difference between every two adjacent porous heating ceramic plates is 180 degrees, and the surfaces of the porous heating ceramic plates are loaded with catalyst films.
11. 11. The apparatus system for use in the sintering connection method according to any one of claims 1 to 8, comprising an argon cylinder, a backflow prevention cylinder, a heating module, a solution cylinder containing formic acid solution, a catalytic module, and a packaging device connected in this order, wherein the packaging device is further connected with a nitrogen cylinder, a sintering control module, an exhaust gas recovery device, a mechanical pump, and a pressurizing device, respectively, and the catalytic module is connected with the catalytic control module.

Description

Low-temperature sintering connection method for nano copper material Technical Field The invention relates to the technical field of electronic packaging, in particular to a low-temperature sintering connection method of a nano copper material. Background With the development of the semiconductor industry, the components of power semiconductors in semiconductor devices are increasingly important, mainly including power metal oxide semiconductor field effect transistors, insulated gate bipolar transistors and power integrated circuits, and international experts have made their development a second revolution in secondary electronics. The high heat conduction DBC substrate material and the chip connecting layer material inside the power semiconductor are packaged by the copper soldering paste, the double problems that the electrical performance is reduced due to Cu oxidation and the strength of the connecting layer is reduced due to a large number of holes generated by volatilization of organic matters exist during sintering, and meanwhile, the power semiconductor cannot work at high temperature during use, so that an efficient low-temperature sintering method for reducing the nano copper material and reducing the porosity in the sintering process is urgently needed in industry. The reduction methods commonly used in sintering are generally classified into two types, namely, adding a reducing substance to a solder paste, but the method is more common, but since the reducing substance only acts on a connection part coated with the solder paste, other parts are oxidized during sintering, thereby affecting the use. Secondly, the reduction is performed by using an atmosphere during sintering, and Li Sujuan and the like (CN 106340802A) directly reduce the sintered sample by using a formic acid atmosphere in the related technology, and the reduction treatment time by directly using formic acid is longer due to the fact that the chemical process of directly reducing CuO by using uncatalyzed formic acid is complex, and the reduction effect is not ideal. Ren et al (Low temperature Cu bonding with large tolerance of surface oxidation.AIP Advances 9,doi:10.1063/1.5097382) uses C powder as a carrier and Pt powder as a catalyst to catalyze formic acid gas for sintering, but the problems that Pt and C powder are easy to mix into a sample during gas blowing, the catalysis effect of a powdery catalyst is insufficient and the like exist. Disclosure of Invention Aiming at the problems existing in the prior art, the invention provides a low-temperature sintering connection method of a nano copper material. The invention provides a low-temperature sintering connection method of a nano copper material, which comprises the steps of sintering in a catalyzed formic acid gas atmosphere, heating to 80-200 ℃ in the sintering process, preserving heat for 5-10min, and continuing sintering for 3-30min under the conditions of 0-30MPa of pressure and 0-280 ℃, wherein the formic acid gas is catalyzed by a catalyst film loaded on the surface of a porous heating ceramic plate. The invention uses the catalyst film loaded on the surface of the porous heating ceramic plate to catalyze the formic acid gas, so that the formic acid gas can be fully catalyzed, the catalyzed formic acid gas is not mixed with the catalyst, the fully catalyzed formic acid is reduced to the nano copper material under a specific sintering process window, and the problems of electrical performance reduction and connection strength reduction caused by copper oxidation in the sintering process can be solved. The nano copper material comprises common copper materials such as copper soldering paste, copper soldering lug with nano structure, copper film and the like. Wherein, the operation of heating to 80-200 ℃ and preserving heat for 5-10min can better solve the problem of performance reduction of the copper soldering paste caused by volatilization of organic matters. According to the low-temperature sintering connection method of the nano copper material, the catalyst film is a Pt nano film or a Pd nano film, and the catalyst film is loaded on the surface of the porous heating ceramic plate through pulse laser deposition. Pulsed Laser Deposition (PLD) is a means of bombarding an object with a laser and then depositing the bombarded material on a different substrate to obtain a deposit or film. This means is well known in the art and can be carried out by conventional procedures. In a specific embodiment of the present invention, the pulsed laser deposition uses high-pressure dual-target coating to improve efficiency. Further, the thickness of the porous heating ceramic plate is 2-50mm, and the thickness of the catalyst film is 10-1000 mu m. According to the low-temperature sintering connection method of the nano copper material, the diameter of the holes on the porous heating ceramic plate is 0.1-5mm, and the catalytic temperature of the porous heating ceramic plate is contr