SiGe Etchant Composition for Rate-Selective Substrate Processing
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Solution Overview
Problem
Existing substrate processing methods struggle to efficiently and selectively remove films, particularly silicon germanium (SiGe), from substrates while controlling etch rate and selectivity, which is crucial for manufacturing semiconductor devices with 3D structures.
Innovation Solution
A substrate processing method involving the use of an etchant prepared with an etching chemical and an etching inhibitor, where the proportion of these components is adjusted to control the etch rate and selectivity for silicon germanium. The etchant supply unit includes a mixer that combines the etching chemical, inhibitor, and deionized water, with a controller regulating the supply flow rates to optimize the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the proportion of etching chemical is increased to increase the etch rate for silicon germanium, then the etch rate is improved, but the selectivity to other materials (silicon and silicon oxide) deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting the proportions of etching chemical and etching inhibitor in the etchant composition to control the etch rate and selectivity. Specifically, the etchant contains hydrogen peroxide (1-10 vol%), acetic acid (5-50 vol%), and etching inhibitor (0.1-5 vol%), where varying these parameters enables optimization of both etch rate and selectivity for different processing stages
Solution Approach 2:
The patent uses a composite etchant formulation combining multiple chemicals (hydrogen peroxide, acetic acid, and etching inhibitor) to achieve both high etch rate and good selectivity. This composite approach allows the etchant to effectively remove silicon germanium while maintaining selectivity against silicon and silicon oxide materials
2Manufacturing precision
If the proportion of etching inhibitor is increased to improve the etch selectivity, then the selectivity is improved, but the etch rate for silicon germanium decreases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the proportion of etching inhibitor in the etchant composition. In the first removal operation, a lower inhibitor proportion (0.1-2 vol%) is used to achieve high etch rate, while in the second removal operation, a higher inhibitor proportion (0.5-5 vol%) is used to achieve high selectivity, thus resolving the contradiction between rate and selectivity
3Ease of manufacture
If a single etchant composition is used for complete removal of silicon germanium, then the process is simple, but the selectivity to remove only silicon germanium without affecting other materials deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the silicon germanium removal process into two distinct operations: a first removal operation that removes the majority of silicon germanium with high etch rate, and a second removal operation that completes the removal with high selectivity. This segmented approach maintains both process simplicity and material selectivity
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 enables efficient and selective removal of silicon germanium films, improving the processing efficiency of substrates and enhancing the manufacturing of semiconductor devices with 3D structures like GAA and CFET.
Implementation Method 1
supplying an etchant for removing silicon germanium (SiGe) provided on a substrate to the substrate, the etchant being prepared with an etching chemical and an etching inhibitor
Implementation Method 2
the etchant being prepared with an etching chemical and an etching inhibitor, in which an etch rate for the silicon germanium and/or an etch selectivity for the silicon germanium is controlled by adjusting a proportion of at least one of the etching chemical and the etching inhibitor
Data Source
AI summary
Disclosed is a method of processing a substrate, the method including: supplying an etchant for removing silicon germanium (SiGe) provided on a substrate to the substrate, the etchant being prepared with an etching chemical and an etching inhibitor, in which an etch rate for the silicon germanium and/or an etch selectivity for the silicon germanium is controlled by adjusting a proportion of at least one of the etching chemical and the etching inhibitor used in the preparation of the etchant.