Contact Field Plate Layout for Precise Etch Depth Control
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Solution Overview
Problem
Existing methods for forming field plates in semiconductor devices face challenges such as increased fabrication costs, restricted placement due to design rules, and difficulty in controlling etching depth, leading to issues like shorting and reduced effectiveness.
Innovation Solution
Forming a field plate by etching an opening in a masking layer and filling it with conductive material without going through an ILD layer, ensuring precise depth control and avoiding etching through dielectric layers, thereby reducing yield loss and enhancing effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing methods are used to form field plates by etching through dielectric layers, then field plates can be formed, but etching depth control becomes difficult leading to shorting and reduced effectiveness
Solution Approach 1:
A contact opening is formed through the interlayer dielectric layer prior to forming the field plate. This preliminary action establishes a depth reference point that enables precise control of the field plate formation process, preventing both over-etching (which causes shorting) and under-etching (which reduces effectiveness).
Solution Approach 2:
The contact opening serves as an intermediary structure that mediates between the etching process and the field plate formation. By using the contact opening as a template and depth guide, the method achieves precise depth control without requiring complex etching parameters, thereby eliminating shorting risks while ensuring adequate field plate effectiveness.
2Reliability
If field plates are formed using existing methods, then electric field management is achieved, but fabrication costs increase
Solution Approach 1:
The field plate formation process is merged with the existing contact opening formation process. By reusing the contact opening as a template for field plate placement and depth reference, the method eliminates the need for separate field plate etching and depth control processes, thereby reducing fabrication costs while maintaining effective electric field management.
Solution Approach 2:
The contact opening structure is given multiple functions: it serves as both the electrical contact pathway and as the depth reference template for field plate formation. This multi-functionality reduces the number of separate structures and processes needed, simplifying fabrication and reducing costs while maintaining field plate effectiveness.
3Reliability
If field plates are formed using existing methods, then electric field management is achieved, but placement is restricted due to design rules
Solution Approach 1:
The field plate formation is localized to areas where contact openings are present. By using the contact opening pattern as the template for field plate placement, the method adapts field plate locations to the specific device layout requirements, providing placement flexibility while ensuring effective electric field management at the necessary locations.
Data Source
AI summary
A semiconductor device and method of forming the semiconductor device are disclosed. The method includes forming first and second conductive structures on a semiconductor substrate, forming one or more dielectric layers between the first and second conductive structures, covering the one or more dielectric layers with a first masking layer, forming a first opening in the first masking layer, depositing a conductive material in the first opening to form a field plate structure, and electrically connecting the field plate structure to another conductor.