Chemical nickel-gold process applied to wafer aluminum-copper base material in field of IGBT (Insulated Gate Bipolar Translator) power devices

Abstract

The invention discloses a chemical nickel-gold process of a wafer aluminum-copper base material applied to the field of IGBT power devices. The chemical nickel-gold process comprises a process flow, an activating solution formula, a chemical nickel formula, a chemical gold formula and the like. The technological process comprises the steps of oil removal, water washing, micro-etching, water washing, presoaking, activation, water washing, vacuum water washing, dry ice spray washing, thin copper electroplating, water washing, chemical nickel plating, water washing and chemical gold plating. The formula of the activating solution comprises ruthenium salt, platinum salt, concentrated sulfuric acid, a surfactant, a stabilizer, a complexing agent and a dispersing agent. The nickel plating formula comprises nickel salt, a complexing agent, a brightening agent, a reducing agent, a stabilizing agent, a bridging agent and a carrying agent. The gold plating formula comprises gold salt, a complexing agent, a stabilizing agent, an underpotential agent, a reducing agent and a nucleating agent. The excellent chemical nickel-gold plating process of the wafer aluminum-copper base material in the field of IGBT power devices can be realized, and the chemical nickel-gold plating process has the characteristics of being excellent in stability, bright and smooth, free of skip plating and diffusion plating, good in oxidation resistance, good in weldability and the like.

Description

technical field [0001] The invention relates to the technical field of electroless nickel-gold plating, in particular to an electroless nickel-gold process applied to wafer aluminum-copper substrates in the field of IGBT power devices. Background technique [0002] IGBT, also known as insulated gate bipolar transistor, is a composite fully-controlled voltage-driven power semiconductor device composed of BJT (bipolar transistor) and MOS (insulated gate field effect transistor), and has the high input impedance of MOSFET And the advantages of low conduction voltage drop of GTR, so it is widely used in rail transit, smart grid, electric vehicles and new energy equipment and other fields. [0003] The chemical nickel-gold process has excellent oxidation resistance, conductivity and welding performance. Liu Qiyuan and others disclosed a nickel-plating process for the copper substrate of the inverter IGBT in the patent CN112030198A. Although the nickel-plating process has a good n...

AI Technical Summary

Problems solved by technology

[0003] The chemical nickel-gold process has excellent oxidation resistance, conductivity and welding performance. Liu Qiyuan and others disclosed a nickel-plating process for the copper substrate of the inverter IGBT in the patent CN112030198A. Although the nickel-plating process has a good nickel layer Ductility, but the wetting agent used in nickel plating is quaternary ammonium chloride. Due to the thin lines at the wafer level, the corrosion of chlorides can easily cause line disconnection and affect product yield.

[0004] In addition, Wang Jiangfeng et al. disclosed in patent CN109518172A a kind of chemical nickel solution applied in wafer-level packaging chemical nickel-gold process, which contains pyridine compounds with strong coordination effect, but poor activity in nickel itself. There must be a catalytic functional substance as an initiator, which is accelerated under the action of a reducing agent. The nickel plating in this bath is relatively slow, and the temperature requirement is high, which is not suitable for production needs.

Images