Layered Tungsten Mask Etching for Uniform Semiconductor Recesses
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of recesses in semiconductor devices is often inconsistent due to the material and etching conditions of the mask layer, leading to shape abnormalities and reduced circularity in the etched features.
Innovation Solution
A semiconductor manufacturing method involving a mask material with layered structures of varying tungsten content, where the first mask layer has a lower tungsten content and the second mask layer has a higher tungsten content, allowing for precise etching by switching between different temperatures and gases to achieve high selectivity and prevent shape abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer mask material is used for etching, then the manufacturing process is simple, but the recess formation is inconsistent and shape abnormalities occur
Solution Approach 1:
The mask material is divided into multiple layers with different tungsten contents. The first mask layer has lower tungsten content (0-50 at%) and the second mask layer has higher tungsten content (50-100 at%). This segmentation allows different layers to serve different etching functions, improving recess formation consistency while maintaining etching selectivity.
Solution Approach 2:
Different regions of the mask material have different tungsten concentrations tailored to specific etching requirements. The lower tungsten content region provides better etching selectivity for shallow recesses, while the higher tungsten content region provides better structural stability for deep recesses, ensuring consistent formation across varying depths.
2Reliability
If high tungsten content mask material is used, then etching selectivity is high, but shape abnormalities and reduced circularity occur
Solution Approach 1:
The etching process dynamically switches between etching conditions optimized for different mask layer regions. The system adapts etching parameters based on the local tungsten content, allowing high selectivity where needed while maintaining shape uniformity in other regions, thus resolving the contradiction between selectivity and shape quality.
3Shape
If low tungsten content mask material is used, then shape uniformity is maintained, but etching selectivity decreases
Solution Approach 1:
The mask material is segmented into layers with different tungsten contents to simultaneously provide high etching selectivity and shape uniformity. The first layer with lower tungsten content maintains shape uniformity, while the second layer with higher tungsten content provides etching selectivity, resolving the contradiction between these two properties.
Data Source
AI summary
A method for manufacturing a semiconductor device includes forming, on a to-be-processed film above an underlying film, a mask material containing a first metal and comprising a first mask layer which is provided on the to-be-processed film and whose content of the first metal is lower than a first predetermined percentage, and a second mask layer which is provided on the first mask layer and whose content of the first metal is equal to or higher than the first predetermined percentage. The manufacturing method includes patterning the mask material. The manufacturing method includes processing the to-be-processed film using the mask material as a mask. The processing of the to-be-processed film includes performing a first treatment to process the to-be-processed film at a first temperature in an atmosphere of a first gas. The processing of the to-be-processed film includes performing a second treatment to process the to-be-processed film at a second temperature higher than the first temperature in an atmosphere of a second gas different from the first gas.