IF5-IF7 Mixed Gas for Stable Substrate Etching
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Solution Overview
Problem
The existing techniques for producing IF7 gas, such as those described in Patent Document 1, face issues with variability in etching rates during substrate processing, leading to inconsistent etching conditions and product quality.
Innovation Solution
A substrate processing gas containing a mixture of IF5 and IF7, with IF5 concentrations between 1 ppm and 2% by volume, is used to stabilize the etching rate and prevent decomposition of IF7, thereby maintaining a consistent etching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If IF7 single gas is used as substrate processing gas, then the maximum etching rate is achieved, but variation in the etching rate increases
Solution Approach 1:
The patent changes the compositional parameters of the processing gas by adding IF5 to IF7 in specific proportions (0.1-10 vol%). This parameter change resolves the contradiction by maintaining high etching rate while reducing variation through controlled gas mixture composition.
Solution Approach 2:
The patent creates a composite gas system by mixing IF5 and IF7 in specific ratios. This composite approach allows the system to achieve both high productivity (etching rate) and reliability (low variation) by combining the beneficial effects of both gases.
2Reliability
If IF5 is added to IF7 to suppress etching rate variation, then the variation in etching rate decreases, but the etching rate may be lowered
Solution Approach 1:
The patent optimizes the concentration parameters of IF5 in the gas mixture (0.1-10 vol%, preferably 0.5-5 vol%). By precisely controlling this parameter, the patent achieves low etching rate variation while maintaining high etching rate, resolving the contradiction between reliability and productivity.
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
The mixed gas achieves a higher etching rate with reduced variability, ensuring stable etching conditions and improved product quality by controlling the IF5 content within specific limits.
Implementation Method 1
since IF5 may suppress decomposition of IF7 generated in the IF7 single gas
Implementation Method 2
dry-etching silicon without plasma, using the substrate processing gas
Data Source
AI summary
A substrate processing gas of the present invention contains IF5; and IF7, in which a content of the IF5 is equal to or more than 1 ppm and equal to or less than 2% on a volume basis with respect to a total amount of the IF5 and the IF7.