Selective HF Dry Etching of Re-Growth Silicon Oxide
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for suppressing re-growth silicon oxide generation during wet-etching of silicon nitride layers in semiconductor manufacturing are inefficient, leading to prolonged process times and degraded electrical characteristics due to the re-growth silicon oxide's impact on subsequent processes.
Innovation Solution
A dry-etching method using HF and H2O as an etching gas at 40°C or lower is employed to selectively remove re-growth silicon oxide formed on silicon oxide layers, with controlled substrate temperature, pressure, and flow rates to enhance etch selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional methods are used to suppress re-growth silicon oxide generation during wet-etching, then the re-growth silicon oxide is reduced, but the process time becomes very long
Solution Approach 1:
The patent changes the fundamental parameter of the etching method from wet-etching to dry-etching, and further specifies using HF-based dry-etching at controlled temperatures (20°C or lower). This parameter change enables selective removal of re-growth silicon oxide while maintaining short process times, resolving the contradiction between reducing harmful re-growth oxide and keeping process time short.
2Manufacturing precision
If phosphoric acid-based etchant is used to selectively etch silicon nitride layers, then etch selectivity is improved, but re-growth silicon oxide is generated on silicon oxide layers
Solution Approach 1:
The patent extracts and removes the harmful re-growth silicon oxide that is generated during the phosphoric acid-based wet-etching process. By applying HF-based dry-etching selectively, the re-growth oxide is taken out from the silicon oxide layer surface, thereby resolving the contradiction between achieving good etch selectivity and preventing harmful re-growth oxide formation.
Solution Approach 2:
The patent introduces HF-based dry-etching as an intermediary process between the phosphoric acid wet-etching and subsequent processing steps. This intermediary step selectively removes the re-growth silicon oxide without affecting the underlying silicon oxide layer or previously etched structures, thus resolving the contradiction between using phosphoric acid for selectivity and preventing re-growth oxide.
3Object-generated harmful factors
If additives are adjusted in phosphoric acid-based etchant to suppress re-growth silicon oxide, then re-growth silicon oxide is reduced, but the wet-etching process time increases significantly
Solution Approach 1:
The patent replaces the chemical mechanism of phosphoric acid-based wet-etching with an HF-based dry-etching mechanism. This substitution eliminates the need for additive adjustments and long process times associated with suppressing re-growth oxide in wet-etching, while achieving the same or better effect of reducing re-growth silicon oxide, thereby resolving the contradiction between reducing harmful factors and maintaining 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 method effectively removes re-growth silicon oxide with high selectivity, reducing process time and minimizing damage to the silicon oxide layer, thereby improving semiconductor device performance.
Implementation Method 1
supplying an etching gas into the reaction chamber to dry-etch the re-growth silicon oxide formed on the surface of the silicon oxide layer, wherein the dry-etching is performed using HF and H2O as an etching gas at about 40° C. or lower
Data Source
AI summary
Disclosed is a substrate processing method for selectively etching a re-growth silicon oxide formed on a surface of a silicon oxide layer and having a density lower than a density of the silicon oxide layer. The method includes: (a) placing a substrate including the re-growth silicon oxide into a reaction chamber; and (b) supplying an etching gas into the reaction chamber to dry-etch the re-growth silicon oxide formed on the surface of the silicon oxide layer, wherein the dry-etching is performed using HF and H2O as an etching gas at about 40° C. or lower.