Etch Process Control via Empirical Modeling
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Solution Overview
Problem
Existing etch process control systems often prioritize certain etch characteristics over others, leading to secondary etch characteristics falling outside desired tolerances, potentially resulting in defective semiconductor devices.
Innovation Solution
A system and method that utilize an etching tool, a metrology tool, and a controller with processors to execute multiple etch recipes, generate metrology data, determine relationships between control parameters and etch characteristics, and create an empirical process model to optimize primary etch characteristics while maintaining secondary etch characteristics within defined bounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple etch characteristics are optimized simultaneously, then overall etch quality improves, but the complexity of the control system increases
Solution Approach 1:
The system segments the optimization process into multiple discrete etch recipes, each targeting specific etch characteristics. Instead of attempting to optimize all characteristics in a single complex control loop, the system divides the problem into manageable segments (individual recipes) that can be executed and measured separately, then combines the results to achieve overall optimization.
Solution Approach 2:
The system performs preliminary action by executing multiple etch recipes and collecting metrology data before finalizing the optimal process parameters. This preliminary experimentation allows the system to build an empirical process model that captures the relationships between control parameters and etch characteristics, simplifying the subsequent control decisions.
Data Source
AI summary
A system for controlling an etch process includes an etching tool, a metrology tool, and a controller. The etching tool is controllable via a set of control parameters and may execute a plurality of etch recipes containing values of the set of control parameters. The controller may direct the etching tool to execute a plurality of etch recipes on a plurality of metrology targets; direct the metrology tool to generate metrology data indicative of two or more etch characteristics on the plurality of metrology targets; determine one or more relationships between the two or more etch characteristics and the set of control parameters based on the metrology data; and generate, based on the one or more relationships, a particular etch recipe to constrain one of the two or more etch characteristics and maintain the remainder of the two or more etch characteristics within defined bounds.