Semiconductor Fin Structure Etching With ClF3 for CD Uniformity
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Solution Overview
Problem
The increasing complexity of semiconductor manufacturing processes due to scaling down in IC technology has made it challenging to maintain uniformity and efficiency in etching processes, leading to non-uniform etching rates and loading effects that affect device performance and yield.
Innovation Solution
The use of a selective dry etching process with a gas etchant comprising ClF3 is employed to selectively remove edge portions of semiconductor layers, ensuring uniform etching by minimizing the loading effect and maintaining consistent critical dimensions across varying pitches and fin widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used in scaled-down IC manufacturing, then productivity is maintained, but manufacturing precision deteriorates due to non-uniform etching rates and loading effects
Solution Approach 1:
The patent changes the chemical parameters of the etching process by using ClF3 gas as the etchant, which has unique properties that enable uniform etching across different geometries. This parameter change resolves the contradiction by maintaining etching uniformity (improving manufacturing precision) while preserving processing efficiency (maintaining productivity)
Solution Approach 2:
The patent replaces conventional plasma etching mechanisms with a gas-phase chemical etching process using ClF3. This substitution eliminates the loading effects inherent in traditional plasma processes, achieving uniform etching rates across varying pitches and fin widths without sacrificing productivity
2Productivity
If geometry size is decreased to increase functional density, then productivity is improved, but manufacturing precision deteriorates due to increased process complexity
Solution Approach 1:
By changing the etching chemistry to use ClF3 gas, the patent achieves precise control over critical dimensions at scaled geometries. The unique chemical properties of ClF3 enable consistent etching rates and uniform profile formation, maintaining manufacturing precision while supporting continued scaling for improved productivity
3Adaptability or versatility
If etching process complexity is increased to handle varying pitches and fin widths, then adaptability is improved, but manufacturing precision deteriorates due to loading effects
Solution Approach 1:
The patent replaces complex, geometry-dependent etching processes with a simplified gas-phase chemical etching using ClF3. This substitution inherently provides adaptability to varying pitches and fin widths while eliminating loading effects, thereby maintaining etching uniformity without requiring increased process complexity
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 approach achieves consistent and controlled etching results, reducing the loading effect and improving device performance and yield by maintaining precise critical dimensions and uniformity across different geometries.
Implementation Method 1
The use of a selective dry etching process with a gas etchant comprising ClF3 is employed to selectively remove edge portions of semiconductor layers
Implementation Method 2
The use of a selective dry etching process with a gas etchant comprising ClF3 is employed to selectively remove edge portions of semiconductor layers
Data Source
AI summary
A method includes forming a fin structure on a substrate, wherein the fin structure includes a first plurality of semiconductor layers made of a first semiconductor material and a second plurality of semiconductor layers made of a second semiconductor material, forming a sacrificial gate stack over the fin structure, removing portions of the fin structure adjacent to the sacrificial gate stack to expose a portion of the substrate, removing edge portions of the second plurality of semiconductor layers in a lateral direction to form recesses, wherein removing the edge portions includes performing a selective dry etching process using a gas etchant that includes ClF3, forming inner spacers in the recesses, forming a source/drain (S/D) region adjacent to the sacrificial gate stack, removing the sacrificial gate stack and the second plurality of semiconductor layers, and forming a gate structure in place of the sacrificial gate stack and the second plurality of semiconductor layers.