Multilayer Masking Structure for Selective CMOS Region Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices continue to reduce minimum feature sizes for increased integration density, challenges arise in efficiently patterning and processing semiconductor layers to form high-performance transistors while maintaining precise control over mask layers for p-type and n-type regions.
Innovation Solution
A method is developed for forming multilayer masking layers that allow selective etching and processing of semiconductor layers, enabling the formation of p-type and n-type transistor regions with improved efficiency and ease of removal, using high-etch selectivity materials and self-aligned processes to create nanostructures and gate structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-layer mask layers are used for patterning semiconductor layers, then the manufacturing process is simpler, but the etching selectivity and precision for p-type and n-type regions deteriorate
Solution Approach 1:
The mask layer is divided into multiple sub-layers (first mask layer, second mask layer, third mask layer) with different materials and etching selectivities. Each sub-layer is selectively etched to define different regions (p-type source/drain regions, n-type source/drain regions) with high precision, resolving the contradiction between structural complexity and etching precision.
Solution Approach 2:
Different portions of the mask structure are assigned different materials and etching characteristics. The first mask layer has high etching selectivity for p-type regions, while the second and third mask layers provide selective protection for n-type regions. This local differentiation enables precise control over etching processes for different transistor types.
2Manufacturing precision
If multiple mask layers are used for selective etching, then the etching precision and selectivity improve, but the manufacturing complexity increases
Solution Approach 1:
The mask layers are formed with predetermined materials and structures before the etching process. The first mask layer is formed with high etching selectivity to define p-type regions, followed by formation of second and third mask layers for n-type region definition. This preliminary structuring enables subsequent selective etching with high precision.
Solution Approach 2:
The multiple mask layers act as intermediary structures that facilitate selective etching of semiconductor layers. Each mask layer serves as a mediator that protects certain regions while allowing etching in other regions, enabling precise patterning without requiring direct manipulation of the semiconductor layers themselves.
3Ease of manufacture
If conventional mask layers are used, then the manufacturing process is easier, but the ease of removal and regeneration deteriorates
Solution Approach 1:
The mask layers are designed to be selectively removed after serving their patterning function. The first mask layer is removed after defining p-type regions, and the second and third mask layers are removed after defining n-type regions. This selective removal enables regeneration of mask structures for subsequent processing steps without requiring complete mask layer replacement.
Data Source
AI summary
A method includes forming a semiconductor layer over a substrate; etching a portion of the semiconductor layer to form a first recess and a second recess; forming a first masking layer over the semiconductor layer; performing a first thermal treatment on the first masking layer, the first thermal treatment densifying the first masking layer; etching the first masking layer to expose the first recess; forming a first semiconductor material in the first recess; and removing the first masking layer.