Tri-Layer Resist System for Etch Selectivity and Resolution
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Solution Overview
Problem
The semiconductor industry faces challenges in scaling down feature sizes due to the thickness requirement of photoresist layers, which affects imaging resolution and etch selectivity, particularly with tri-layer resist materials that lack sufficient etch selectivity for patterning.
Innovation Solution
A tri-layer resist system is developed, comprising a silicon-containing middle layer with thermal base generator additives, which undergoes cross-linking reactions during thermal treatment to increase silicon concentration and etch selectivity, and a photosensitive top layer for improved lithography processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If photoresist thickness is increased to provide sufficient etch resistance, then etch resistance is improved, but imaging resolution deteriorates due to depth of focus degradation
Solution Approach 1:
The photoresist system is divided into multiple functional layers: a first photoresist layer providing etch resistance, a second photoresist layer providing imaging resolution, and an intermediate layer between them. This segmentation allows each layer to be optimized for its specific function without compromising the other, resolving the contradiction between etch resistance and imaging resolution
Solution Approach 2:
The patent employs a composite multi-layer photoresist structure where different photoresist materials with complementary properties are combined. The first photoresist layer is selected for high etch resistance, while the second layer is selected for high imaging resolution, creating a composite system that achieves both properties simultaneously
2Manufacturing precision
If tri-layer resist is introduced to overcome thickness challenges, then etch resistance and imaging resolution are improved, but etch selectivity is insufficient for effective patterning
Solution Approach 1:
The patent applies local quality by selecting photoresist materials with specific local properties for each layer. The first photoresist layer is specifically selected to have high etch resistance with respect to the underlying substrate, while the second layer is selected for high imaging resolution. This localized optimization of material properties throughout the stack achieves both improved imaging resolution and sufficient etch selectivity between layers
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
The solution enhances etch selectivity and imaging resolution by increasing silicon concentration in the middle layer, allowing for more precise pattern transfer and efficient processing in semiconductor fabrication.
Implementation Method 1
undergoes cross-linking reactions during thermal treatment to increase silicon concentration and etch selectivity
Data Source
AI summary
A lithography method is provided in accordance with some embodiments. The lithography method includes forming an under layer on a substrate; forming a silicon-containing middle layer on the under layer, wherein the silicon-containing middle layer has a thermal base generator (TBG) composite; forming a photosensitive layer on the silicon-containing middle layer; performing an exposing process to the photosensitive layer; and developing the photosensitive layer, thereby forming a patterned photosensitive layer.