Substrate Processing Apparatus Etching Uniformity via Periodic Pressure Cycles
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Solution Overview
Problem
The etching process in semiconductor device manufacturing often suffers from non-uniformity across the substrate plane, leading to inefficiencies and inconsistencies in film removal.
Innovation Solution
A technique involving a cycle of supplying etching gas into a process chamber while increasing and then decreasing internal pressure, specifically using HCl gas and vacuum exhaust steps, to uniformly etch a film formed on a substrate, ensuring consistent etching across the substrate plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a film is etched using conventional continuous etching methods, then the etching process can be completed, but the uniformity of etching across the substrate plane deteriorates
Solution Approach 1:
The etching process employs periodic pressure variation cycles, alternating between pressure increase phases (with etching gas supply) and pressure decrease phases (with gas supply stopped). This periodic action ensures uniform etching across the substrate plane while maintaining efficient material removal rates.
2Productivity
If etching gas is supplied continuously to maintain high etching rate, then productivity improves, but gas consumption increases
Solution Approach 1:
The method supplies etching gas only during pressure increase phases and stops supply during pressure decrease phases. This periodic gas supply pattern reduces overall gas consumption while maintaining high etching rates during active etching phases, resolving the contradiction between productivity and gas usage.
3Ease of operation
If pressure is increased continuously during etching, then gas supply efficiency improves, but etching uniformity across substrate deteriorates
Solution Approach 1:
The process alternates between pressure increase phases (improving gas supply efficiency) and pressure decrease phases (restoring etching uniformity). This periodic pressure variation resolves the contradiction by allowing high gas supply efficiency only when needed, followed by uniformity restoration phases.
Solution Approach 2:
The method dynamically adjusts pressure conditions during the etching process, transitioning between different pressure states rather than maintaining a constant pressure. This dynamic pressure control enables optimization of both gas supply efficiency and etching uniformity at different stages of the process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method improves the uniformity and efficiency of the etching process, reduces gas usage, and enhances productivity by maintaining the amorphous state of the silicon film, thus preventing crystallization and surface unevenness.
Implementation Method 1
etching a portion of a first film formed on a surface of a substrate by performing a cycle a predetermined number of times, the cycle including: supplying an etching gas into a process chamber
Implementation Method 2
lowering the internal pressure of the process chamber by exhausting an interior of the process chamber
Data Source
AI summary
There is provided a technique that includes: etching a portion of a first film formed on a surface of a substrate by performing a cycle a predetermined number of times, the cycle including: supplying an etching gas into a process chamber while raising an internal pressure of the process chamber in a state in which the substrate having the first film formed on the surface of the substrate is accommodated in the process chamber; and lowering the internal pressure of the process chamber by exhausting an interior of the process chamber in a state in which supply of the etching gas into the process chamber is stopped.