Gate Electrode Coupling for Etchant Control in Power Semiconductors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing power semiconductor devices face manufacturing defects due to voids formed in the aluminum electrode film during the etching process, which can lead to failures in metal process treatment, as the etching solution penetrates through elongated voids in the electrode film.
Innovation Solution
The design includes a plurality of gate electrodes protruding via a gate insulating film from the active cell region, with a gate electrode coupling portion outside the active cell region covered by a metal electrode, preventing defects by acting as a dam to prevent the etchant from reaching the active cell region during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the aluminum electrode film is patterned by wet etching, then the metal electrode can be formed, but the etching solution penetrates through voids in the electrode film and causes unwanted etching of the active cell region
Solution Approach 1:
The gate electrode coupling portion is segmented into a first portion (within active cell region) and a second portion (outside active cell region). The second portion extends beyond the metal electrode film to form a protective protrusion that prevents etchant penetration while the first portion maintains electrical connectivity within the active region.
Solution Approach 2:
The second portion of the gate electrode coupling portion acts as an intermediary protective structure between the etching solution and the active cell region. It physically blocks the etchant from reaching the aluminum electrode film in the active cell region during the wet etching process.
2Reliability
If a continuous aluminum electrode film is used to cover the gate electrodes, then good electrical connectivity is achieved, but voids form in the film which allow etchant penetration
Solution Approach 1:
The gate electrode coupling portion is divided into two functional segments: the first portion embedded in the active cell region for electrical connectivity, and the second portion extending outside the metal electrode film to provide etchant protection. This segmentation allows the structure to simultaneously achieve both electrical connectivity and etchant barrier functions.
Solution Approach 2:
The second portion of the gate electrode coupling portion extends in the planar dimension beyond the metal electrode film, creating a three-dimensional protective structure. This dimensional extension allows the coupling portion to serve dual purposes: maintaining electrical connectivity in the active region while providing lateral protection against etchant penetration.
3Ease of manufacture
If the gate electrodes are coupled outside the active cell region, then manufacturing flexibility is improved, but the coupling portion may be exposed to etchant damage
Solution Approach 1:
The second portion of the gate electrode coupling portion serves as a protective intermediary that extends beyond the metal electrode film. This intermediary structure shields the coupling portion from direct etchant exposure while allowing the coupling function to be performed outside the active cell region for manufacturing flexibility.
Solution Approach 2:
The gate electrode coupling portion is designed with an extended second portion before the etching process occurs. This preliminary structural configuration ensures that when wet etching is performed, the coupling portion is already protected by its own extended structure, preventing etchant damage before it can occur.
Data Source
AI summary
A general insulated gate power semiconductor active element with many gate electrodes arranged in parallel has a laminated structure including a barrier metal film and a thick aluminum electrode film formed over the gate electrodes via an interlayer insulating film. When the aluminum electrode film is embedded in between the gate electrodes in parallel, voids may be generated with the electrodes. Such voids allow the etchant to penetrate in wet etching, which may promote the etching up to a part of the electrode film in an active cell region which is to be left. Thus, an insulated gate power semiconductor device is provided to include gate electrodes protruding outward from the inside of the active cell region, and a gate electrode coupling portion for coupling the gate electrodes outside the active cell region. The gate electrode coupling portion is covered with a metal electrode covering the active cell region.