Silicon Nitride Etching via Surface Oxidation for Precise Removal
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Solution Overview
Problem
Existing etching technologies for silicon nitride films lack the ability to control the amount of etching effectively.
Innovation Solution
A substrate processing method involving oxidation of the target film surface to form an oxide film, followed by selective etching using chemical oxide removal (COR) and post-heat treatment (PHT) to control the etching amount, utilizing gases like hydrogen, oxygen, hydrogen fluoride, and ammonia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used for silicon nitride films, then etching can be performed, but the amount of etching cannot be controlled effectively
Solution Approach 1:
The etching process is segmented into two distinct stages: first oxidizing the silicon nitride film surface to form a silicon oxide layer, then selectively removing this oxide layer. This segmentation allows independent control of each step, enabling precise control over the final etching amount by adjusting oxidation time, temperature, or oxygen concentration.
Solution Approach 2:
The oxidation step is performed as a preliminary action before the actual etching. By pre-forming a controlled thickness oxide layer on the silicon nitride film surface through oxidation, the subsequent etching process can remove a precise amount of material. The oxide layer thickness, controlled during the preliminary oxidation step, directly determines the etching amount.
2Manufacturing precision
If oxidation is used to form an oxide film followed by etching, then etching amount control is improved, but process complexity increases
Solution Approach 1:
The oxidation and etching steps are merged into a single integrated process sequence within the same reaction chamber. The oxidation phase uses oxygen-containing atmosphere to form the oxide layer, and the etching phase uses a different gas atmosphere to remove the oxide. This merging allows both functions to be achieved without requiring separate equipment, managing complexity while maintaining precision control.
Solution Approach 2:
The process controls etching amount by changing parameters during the oxidation step (oxygen concentration, temperature, time) rather than during etching. By adjusting these parameters, the oxide layer thickness is precisely controlled, which in turn controls the etching amount. This parameter change approach simplifies control compared to trying to control etching rate directly.
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
Enables precise control over the etching amount of the target film by adjusting the oxide film thickness formed during oxidation, enhancing productivity and efficiency in etching silicon nitride films.
Implementation Method 1
supplying hydrogen gas and oxygen gas to the target film to oxidize a surface layer of the target film and form an oxide film
Implementation Method 2
supplying hydrogen fluoride gas to the oxide film to etch the oxide film
Implementation Method 3
supplying ammonia gas to the oxide film to etch the oxide film
Data Source
AI summary
A substrate processing method includes preparing a substrate having a target film including silicon, carbon, and nitrogen on a surface of the substrate; supplying hydrogen gas and oxygen gas to the target film to oxidize a surface layer of the target film and form an oxide film; and etching the oxide film.