Mask Blank Buffer Layer Neutralizes Acids to Preserve Resist Sensitivity
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Solution Overview
Problem
The existing methods for manufacturing mask blanks with chemically amplified resist layers face issues such as sensitivity reduction due to acids and bases in protective layers, moisture penetration, and adhesion problems between layers, which affect the formation of fine patterns in semiconductor manufacturing.
Innovation Solution
A mask blank structure is developed with a chemically amplified resist layer, a buffer layer, and a protective layer containing acidic and basic substances, where the buffer layer maintains pH balance and prevents excessive invasion of acids or bases, and the protective layer is soluble in water or alkaline solutions, ensuring high adhesion and maintaining resist sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is formed on the chemically amplified resist layer, then the resist layer is protected from foreign matters, but the sensitivity of the chemically amplified resist layer is reduced due to acids and bases in the protective layer
Solution Approach 1:
A buffer layer is introduced as an intermediary between the protective layer and the chemically amplified resist layer. This buffer layer contains basic substances that neutralize acids from the protective layer, preventing sensitivity reduction while maintaining protection functionality. The buffer layer acts as a chemical mediator that allows the protective layer to remain in place without harming the resist layer's sensitivity.
2Object-affected harmful factors
If a protective layer is formed on the chemically amplified resist layer, then foreign matters are prevented from adhering, but moisture and outgas penetrate through the protective layer and reduce sensitivity
Solution Approach 1:
The buffer layer serves as a protective intermediary that absorbs harmful substances (acids, moisture, outgas) before they reach the chemically amplified resist layer. It acts as a chemical barrier that maintains the integrity and sensitivity of the resist layer while allowing the outer protective layer to provide physical protection against foreign matter adhesion.
3Reliability
If the protective layer is separated from the chemically amplified resist layer, then adhesion problems are avoided, but uneven places are generated on the main surface of the mask blank
Solution Approach 1:
The buffer layer acts as an adhesion intermediary between the protective layer and the chemically amplified resist layer. It provides chemical bonding sites that ensure strong, uniform adhesion of the protective layer, preventing separation and the formation of uneven surfaces. The buffer layer's basic substances form chemical bonds with both layers, ensuring stable attachment.
4Manufacturing precision
If exposure is performed to the chemically amplified resist layer, then the exposed portion is modified for pattern formation, but the property of the exposed portion changes and prevents developing solution from entering
Solution Approach 1:
The buffer layer serves as a chemical intermediary that facilitates the interaction between the developing solution and the exposed resist layer. During exposure, the buffer layer undergoes chemical changes that improve its solubility, allowing the developing solution to penetrate through it and reach the exposed resist patterns for proper development.
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 configuration effectively protects the resist layer from foreign matters and maintains sensitivity, enabling the formation of fine patterns with improved adhesion and resistance to environmental contaminants, even after exposure and development.
Implementation Method 1
the protective layer contains an acidic substance, a basic substance, and a salt generated by a reaction between the acidic substance and the basic substance
Implementation Method 2
when the mask blank is stored or transferred, foreign matters are adhered to an outermost surface of the mask blank
Implementation Method 3
the sensitivity of the chemically amplified resist layer is reduced due to a component such as acids and bases contained in the protective layer, or moisture and outgas penetrated through the protective layer
Data Source
AI summary
Provided is a mask blank, including: a resist layer formed by a chemically amplified resist; a protective layer formed to coat the resist layer; and a buffer layer provided between the resist layer and the protective layer, wherein the protective layer contains an acidic substance, a basic substance, and a salt generated by a reaction between the acidic substance and the basic substance, and the buffer layer has a portion which is a surface layer portion of a pre-coated resist layer before being coated by the protective layer, and in which the pre-coated resist layer and the protective layer 4 are in contact with each other, and this portion is formed by receiving the acidic substance, the basic substance, and the salt moved from the protective layer 4.