CN-114695637-B - Thermoelectric grain welding method

CN114695637BCN 114695637 BCN114695637 BCN 114695637BCN-114695637-B

Abstract

The invention provides a thermoelectric grain welding method, which is characterized in that a metallized graphene flexible layer is constructed on a welding interface based on the existing alloy solder welding technology, and stable metallurgical connection between graphene and an electrode layer is realized through a thermocompression bonding method. According to the invention, through designing the thermoelectric device welding interface material and structure, under the condition that the thermal and electrical transmission performance and the force connection stability are not affected, the thermal stress matching of the welding interface is optimized, and meanwhile, the nickel-metallized graphene structure can effectively play a role of a copper atom barrier layer, so that the stability and long-term stable service capability of the device are improved.

Inventors

SONG XIAOHUI
ZHAO LANPU
ZHANG YANCHANG
LIANG NAN
WANG QIFU
WANG JIANYE
WU SHUNLI

Assignees

河南省科学院应用物理研究所有限公司
河南省科学院

Dates

Publication Date: 20260505
Application Date: 20220215

Claims (10)

1. A method of thermoelectric die bonding comprising the steps of: 1) Preparing a nano metal needle cone structure on the surface of a copper structure layer of the copper-clad substrate to obtain the copper-clad substrate with the nano metal needle cone on the surface; the diameter of the cone bottom of the nanometer metal needle cone is 20-50 nm; The length of the nanometer metal needle cone is 10-30 nm; depositing a copper metal layer on graphene to obtain a graphene-copper composite material; the graphene is a graphene film layer; 2) Transferring the graphene-copper composite material to the surface of a copper-clad substrate, enabling a copper metal layer to face a nano metal needle cone on the surface of the copper-clad substrate, depositing nickel metal on the surface of the graphene, and performing hot pressing to obtain a semi-finished product; The pressure of the hot pressing is 1-5 MPa; The temperature of the hot pressing is 250-350 ℃; 3) And welding the semiconductor crystal grain with the metal barrier layer deposited on the surface and the semi-finished product obtained by the steps through solder to obtain the welding integrated package of the thermoelectric crystal grain single face and the copper-clad substrate.
2. The welding method of claim 1, wherein the nano-metal pin cone comprises a nano-copper pin cone.
3. The method of claim 1, wherein the copper-clad layer on the surface of the copper-clad substrate is a patterned copper structure layer; the copper-clad substrate comprises a copper-clad ceramic substrate.
4. The welding method according to claim 1, wherein the graphene comprises single-layer graphene or multi-layer graphene.
5. The welding method according to claim 1, wherein the specific preparation step of the graphene-copper composite material comprises the steps of preparing a graphene film on a substrate, transferring the graphene film onto a transfer medium, dissolving and removing the substrate, and depositing a copper metal layer on the surface of the graphene; the thickness of the copper metal layer is 5-10 nm; The thickness of the nickel metal is 5-10 nm.
6. The welding method of claim 5, wherein the substrate comprises copper foil; the transfer medium comprises PMMA; the hot pressing is preceded by an annealing treatment step.
7. The welding method according to claim 1, wherein, And the hot pressing time is more than or equal to 30min.
8. The bonding method according to claim 1, wherein the semiconductor die having a metal barrier layer deposited on the surface thereof comprises a semiconductor die having a metal barrier layer deposited on both sides thereof; The semiconductor die comprises bismuth antimonide die; The semiconductor crystal grain is welded with the copper-clad substrate through one surface deposited with the metal barrier layer.
9. The method of soldering as claimed in claim 1, wherein the semiconductor die comprises one or more sets of PN-type rectangular die thermocouple pairs; The metal barrier layer is a nickel layer; The thickness of the nickel layer is 1-3 mu m.
10. The soldering method according to claim 1, wherein the solder comprises eutectic alloy solder; the welding mode comprises vacuum reflow welding; The welding mode further comprises the step of welding the other surface of the semiconductor crystal grain with the copper-clad substrate.

Description

Thermoelectric grain welding method Technical Field The invention relates to the technical field of thermoelectric device manufacturing, in particular to a thermoelectric grain welding method. Background In the manufacturing process of the thermoelectric device, after the thermoelectric material is metallized to form the electrode, the electrode needs to be connected with a package carrier plate metal electrode. At present, alloy solder is filled in a connecting interface by a soldering or brazing method, connection integration is realized after solidification, the temperature is generally about 250-400 ℃, and the function principle is that metal elements composing the solder form eutectic structures at low temperature. The welding method is widely used for electronic manufacturing and has advantages in the aspects of cost, process maturity and the like. In addition, the technologies of electric arc spraying, hot-pressing bonding, spark Plasma Sintering (SPS) and the like are sequentially applied to the packaging and manufacturing of thermoelectric devices, and the thermoelectric device has high connection strength, low interface resistance and thermal resistance and is more suitable for being high Wen Fuyi. However, in the existing welding technology, thermal stress can cause new crack defects to form at the welding interface during service of the thermoelectric device. Therefore, how to obtain a suitable welding mode, solve the above-mentioned problems caused by the existing welding technology, and have become one of the focuses of extensive attention of many prospective researchers in the field. Disclosure of Invention In view of the above, the technical problem to be solved by the present invention is to provide a thermoelectric die bonding method. According to the invention, the single-layer or multi-layer metallized graphene structure of the packaging connection interface is used for realizing stable metallurgical connection of graphene and the metal electrode, and meanwhile, the effect of regulating and controlling the thermal stress of the interface by the graphene structure is exerted, so that the thermal stress absorption capacity of the welding interface is improved. The invention provides a thermoelectric grain welding method, which comprises the following steps: 1) Preparing a nano metal needle cone structure on the surface of a copper structure layer of the copper-clad substrate to obtain the copper-clad substrate with the nano metal needle cone on the surface; depositing a copper metal layer on graphene to obtain a graphene-copper composite material; 2) Transferring the graphene-copper composite material to the surface of a copper-clad substrate so that a copper metal layer faces the copper-clad substrate, depositing nickel metal on the surface of the graphene, and performing hot pressing to obtain a semi-finished product; 3) And welding the semiconductor crystal grain with the metal barrier layer deposited on the surface and the semi-finished product obtained by the steps through solder to obtain the welding integrated package of the thermoelectric crystal grain single face and the copper-clad substrate. Preferably, the nano metal needle cone comprises a nano copper needle cone; the diameter of the cone bottom of the nanometer metal needle cone is 20-50 nm; the length of the nanometer metal needle cone is 10-30 nm. Preferably, the copper-clad layer on the surface of the copper-clad substrate is a copper structure layer with a pattern; the copper-clad substrate comprises a copper-clad ceramic substrate. Preferably, the graphene is a graphene film layer; The graphene comprises single-layer graphene or multi-layer graphene. Preferably, the preparation method of the graphene-copper composite material comprises the steps of preparing a graphene film on a substrate, transferring to a transfer medium, dissolving and removing the substrate, and depositing a copper metal layer on the surface of the graphene; the thickness of the copper metal layer is 5-10 nm; The thickness of the nickel metal layer is 5-10 nm. Preferably, the substrate comprises copper foil; the transfer medium comprises PMMA; the hot pressing is preceded by an annealing treatment step. Preferably, the pressure of the hot pressing is 1-5 MPa; The temperature of the hot pressing is 250-350 ℃; and the hot pressing time is more than or equal to 30min. Preferably, the semiconductor crystal grain with the metal barrier layer deposited on the surface comprises a semiconductor crystal grain with the metal barrier layer deposited on two sides; The semiconductor die comprises bismuth antimonide die; The semiconductor crystal grain is welded with the copper-clad substrate through one surface deposited with the metal barrier layer. Preferably, the semiconductor die comprises one or more sets of PN cuboid die thermocouple pairs; The thickness of the nickel layer is 1-3 mu m. Preferably, the solder comprises eutectic alloy solder; the welding mod