Thermal Base Generator Resist for Double Patterning Damage Reduction
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Solution Overview
Problem
In double patterning processes, chemically amplified resist compositions used in semiconductor manufacturing often result in damage to the first resist pattern during the second patterning step, including thickness loss, line width reduction, and hole diameter increase, especially when using positive resist compositions for both layers.
Innovation Solution
Incorporating a thermal base generator in the first resist composition, which generates a base during a hard bake step before the second patterning, to reduce damage by scavenging acid and maintaining solubility, thereby protecting the first resist pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemically amplified resist composition is used for double patterning, then high resolution and sensitivity are achieved, but the first resist pattern suffers damage during second patterning
Solution Approach 1:
A base component is introduced as an intermediary substance in the first resist composition. This base component acts as a mediator that scavenges acid during the second patterning process, preventing acid from damaging the first resist pattern while allowing the chemically amplified resist to maintain its high resolution and sensitivity properties.
Solution Approach 2:
The base component is incorporated into the first resist composition in advance to preemptively counteract the harmful acid effects that will occur during the second patterning step. This preliminary protective action prevents the first resist pattern from suffering damage such as thickness loss, line width reduction, and hole diameter increase.
2Ease of manufacture
If positive resist composition is used for both layers in double patterning, then process simplicity is maintained, but the first resist pattern experiences severe damage
Solution Approach 1:
The invention modifies only the local composition of the first resist by adding a base component, while keeping both resist layers as positive resist types. This localized modification allows the first resist pattern to resist acid damage without changing the overall positive resist process flow, maintaining ease of manufacture while improving pattern dimension accuracy.
3Length of moving object
If second patterning is conducted on first resist pattern, then narrower pitch is achieved, but the first resist pattern suffers thickness loss and line width reduction
Solution Approach 1:
The base component is built into the first resist composition beforehand to perform preliminary protective action. During the second patterning process, this pre-positioned base component scavenges acid that would otherwise cause thickness loss and line width reduction, enabling the achievement of narrower pitch while maintaining resist film thickness stability.
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 method effectively reduces damage to the first resist pattern, allowing for the formation of a resist pattern with a narrower pitch and improved mask reproducibility, while preventing pattern thinning or elimination during the second patterning step.
Implementation Method 1
a thermal base generator which generates a base upon heating
Implementation Method 2
an acid generator that generates acid upon exposure
Data Source
AI summary
There are provided a method of forming a resist pattern in which a resist pattern is formed on top of a substrate by using a chemically amplified resist composition and conducting patterning two or more times, the method being capable of reducing the extent of damage, caused by the second patterning, imposed upon the first resist pattern that is formed by the first patterning; as well as a resist composition that is useful for forming the first resist pattern in this method of forming a resist pattern. The method includes forming of a first resist pattern using a resist composition containing a thermal base generator as a chemically amplified resist composition during first patterning, and then conducting a hard bake for baking the first resist pattern under a bake condition such that a base is generated from the thermal base generator, prior to the second patterning.