Plasma Etching Shoulder Shape Control via Silicon Deposit
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Solution Overview
Problem
In plasma etching processes, the rounding of shoulder portions during the etching of Si oxide films leads to inaccurate line width formation and pattern deterioration, affecting the mask function in subsequent etching steps.
Innovation Solution
A plasma etching method involving the deposition of a silicon-containing deposit using Si-containing gases, followed by etching with CF-based and CHF-based gases to expose organic film lines, and subsequent ashing and etching processes to maintain precise line shapes and improve mask functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Si oxide film is etched using conventional plasma etching, then the etching process can be completed, but the shoulder portions become rounded leading to inaccurate line width formation
Solution Approach 1:
A silicon-containing deposit is deposited on the Si oxide film before etching as a preliminary protective layer. This deposit prevents the rounding of shoulder portions during the subsequent CF4-based plasma etching process, thereby maintaining accurate line width formation and pattern shape.
Solution Approach 2:
The silicon-containing deposit acts as an intermediary protective layer between the plasma etching process and the Si oxide film. This intermediate layer protects the critical shoulder portions from plasma damage while allowing the etching to proceed, thus preserving the intended pattern geometry.
2Manufacturing precision
If a protective layer is deposited before etching to prevent shoulder rounding, then line width accuracy is improved, but the process complexity increases
Solution Approach 1:
The deposition of the silicon-containing deposit and the subsequent CF4-based plasma etching are combined into a integrated process sequence. The deposit is deposited and then immediately etched without requiring separate protective measure steps, thereby improving precision while minimizing the increase in process complexity.
Solution Approach 2:
The process utilizes changes in plasma chemistry parameters by switching from a deposition process to a CF4-based plasma etching process. This parameter change enables the protective function during deposition and the etching function during plasma treatment, achieving both protection and pattern transfer in a controlled manner.
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 method enhances the precision of line width formation and pattern sustainability by controlling the shape of shoulder portions, ensuring accurate etching and maintaining the mask function.
Implementation Method 1
depositing a silicon-containing deposit by a plasma processing using a Si-containing gas on an object to be processed
Implementation Method 2
a first etching of etching the deposit by plasma of a CF-based gas and a CHF-based gas
Data Source
AI summary
A plasma etching method deposits a silicon-containing deposit by a plasma processing using a Si-containing gas on an object to be processed that includes a film to be processed, an organic film formed in a plurality of narrow linear portions on the film to be processed, and a rigid film that covers both the film to be processed which is exposed between the linear portions and the linear portions. In the plasma etching method, each of the plurality of narrow linear portions of the organic film and the film to be processed between the linear portions are exposed by etching the silicon-containing deposit by plasma of CF-based gas and CHF-based gas after the silicon-containing deposit is deposited.