Front metal process for compression joint IGBT

Abstract

The invention provides a front metal process for a compression joint IGBT. The process comprises the steps that a first front metal layer is deposited on an interlayer dielectric layer; the first front metal layer is subjected to wet etching, so that a first groove which is wide on the upper portion and narrow on the lower portion is formed in the interlayer dielectric layer; a barrier layer is deposited on all surfaces of the current structure, and a barrier layer window in a region where thick metal needs to be formed is opened; the surface, exposed after the window is opened, of the first front metal layer is subjected to pretreatment before deposition, so that an oxide layer is removed; a second front metal layer is deposited on all the surfaces of the current structure; the second front metal layer is subjected to wet etching, so that a second groove is formed in the second front metal layer, wherein the side walls of the second groove incline, and the second groove guides the first groove and is wide on the upper portion and narrow on the lower portion; the second groove is subjected to dry etching, the second front metal layer is etched through, and metal in the first groove is cleared up; a protection slope is formed on the barrier layer wrapped at the upper edge of the first groove, wherein the bottom of the protection slope has a certain width. By means of the front metal process, thick front metal and thin front metal in different wiring regions are obtained.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing technology, in particular, the invention relates to a front metal process of a pressure-connected IGBT. Background technique [0002] Insulated gate bipolar transistor (IGBT) is a composite device of MOSFET and BJT. IGBT combines the advantages of both MOSFET and Bipolar, and has the advantages of high voltage and high current. It is currently widely used in power transmission, high-speed Train traction, industrial drive, clean energy and many other fields. [0003] The traditional IGBT uses wire bonding / welding to form modules, while the crimping IGBT module is directly pressure-connected, which eliminates the points of failure and improves reliability; the internal layout has low inductance and the inductance distribution between chips is consistent; double-sided Heat dissipation reduces thermal resistance; safe operation at high temperatures. Another notable feature is the...

AI Technical Summary

Problems solved by technology

There is only one layer of metal on the front side of the IGBT, and a layer of metal needs to form different thicknesses in different wiring areas, which cannot be achieved by conventional metal etching processes

[0005] In addition, metals with a thickness of more than ten microns have many insurmountable difficulties in photolithography and etching processes

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