Polysilicon Gate Etching Modulation for Crown Defect Control
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Solution Overview
Problem
Conventional semiconductor fabrication techniques often result in crown defects during the etching process of second gate electrodes, which can damage previously fabricated components and require harmful chemicals for removal, posing a challenge in maintaining the integrity of the substrate.
Innovation Solution
A method involving multiple etching modulation sequences is applied, where a first etching process is more selective to polysilicon and a second etching process is more selective to the planarization material, allowing for controlled etching to prevent crown defects without damaging other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a plasma etchback process is applied to reduce the second gate electrode height, then the gate electrode height is adjusted to the predetermined height, but a crown defect is created on the edge of the second gate electrode
Solution Approach 1:
The patent applies periodic action by using alternating etching processes (first etching process and second etching process) in sequences rather than a single continuous etching process. This modulation between different etching processes prevents the formation of crown defects while achieving the desired gate electrode height, as the periodic switching allows controlled removal of material without creating the harmful crown defect at the edges
2Object-generated harmful factors
If chemicals are applied to remove crown defects, then the crown defects are removed, but other materials and components on the substrate are damaged
Solution Approach 1:
The patent applies preliminary anti-action by preventing the formation of crown defects in the first place through the use of modulated etching processes. Instead of allowing crown defects to form and then requiring their removal (which would harm other materials), the etching process is designed to inherently prevent crown defect formation, thereby eliminating the need for harmful chemical removal steps that would damage other substrate materials
3Device complexity
If a single etching process is used to etch the second gate electrode, then the etching process is simple, but crown defects are formed that hinder subsequent material application
Solution Approach 1:
The patent applies segmentation by dividing the etching process into multiple distinct etching processes (first etching process and second etching process) that are applied in alternating sequences. Each etching process has different selectivity characteristics, and by segmenting the overall etching task into these multiple processes, the patent achieves superior surface quality without crown defects while maintaining reasonable 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 effectively prevents the formation of crown defects during the etching process, ensuring the integrity of previously fabricated components and allowing for precise adjustment of the second gate electrode height without damaging other materials on the substrate.
Implementation Method 1
applying a first etching process to the substrate, wherein the first etching process is more selective to polysilicon than the planarization material; and applying a second etching process to the substrate, wherein the second etching process is more selective to the planarization material than the polysilicon
Data Source
AI summary
A method of manufacturing a semiconductor includes applying a planarization material to a substrate and forming an opening in the planarization material. The opening is filled with polysilicon. A plurality of etching modulation sequences are applied to the substrate, each of the etching modulation sequences including: applying a first etching process to the substrate, wherein the first etching process is more selective to polysilicon than the planarization material; and applying a second etching process to the substrate, wherein the second etching process is more selective to the planarization material than the polysilicon.