Nanoimprint Lithography Bi-Layer Resist Pattern Formation
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Solution Overview
Problem
Nanoimprint lithography using negative resist compositions faces challenges in forming high aspect ratio resist patterns without pattern collapse during development or rinsing, and thin resist films lack sufficient etching resistance.
Innovation Solution
A bi-layer resist process using a chemically amplified negative resist composition containing a silsesquioxane resin, where an organic layer and a resist layer are formed on a substrate, and a light transmissive mold with a light-resistant portion is pressed against the resist layer, exposed, and then detached, allowing for superior etching resistance even with thin films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin resist film is used to avoid pattern collapse, then pattern collapse is prevented, but sufficient etching resistance cannot be obtained
Solution Approach 1:
The patent divides the single resist film into two separate layers: a lower organic layer (200-500nm thick) that provides etching resistance, and an upper resist layer (50-200nm thick) that prevents pattern collapse. Each layer performs its specific function independently, resolving the contradiction between etching resistance and pattern stability.
Solution Approach 2:
The patent uses a composite bi-layer resist structure combining different materials with complementary properties. The organic layer material provides chemical resistance for etching processes, while the chemically amplified negative resist composition on top provides pattern fidelity. This composite structure allows simultaneous achievement of etching resistance and pattern stability.
2Manufacturing precision
If a high aspect ratio resist pattern is formed, then fine patterning is achieved, but pattern collapse occurs during development or rinsing
Solution Approach 1:
The patent segments the resist system into two functional layers where the upper chemically amplified negative resist layer (50-200nm) is specifically optimized for high-resolution patterning with good collapse resistance, while the lower organic layer provides mechanical support. This segmentation allows formation of high aspect ratio patterns without collapse.
Solution Approach 2:
The patent changes the thickness parameter of the upper resist layer to 50-200nm, which is thin enough to prevent collapse in high aspect ratio patterns but thick enough to maintain patterning resolution. This parameter optimization resolves the contradiction between fine patterning capability and pattern stability.
3Ease of manufacture
If conventional nanoimprint lithography is used, then equipment cost is reduced, but resist film remains as residue on the mold surface
Solution Approach 1:
The patent uses a composite bi-layer resist structure where the upper chemically amplified negative resist layer has specific chemical composition that enables complete removal from the mold surface after imprinting, while the lower organic layer remains on the substrate. This composite structure eliminates resist residue on the mold while maintaining the cost advantages of conventional nanoimprint lithography equipment.
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 prevents pattern collapse and achieves high aspect ratio resist patterns with improved etching resistance, enabling the formation of fine resist patterns without residue and maintaining resolution.
Implementation Method 1
exposing from above the mold; and detaching the mold
Implementation Method 2
forming a resist layer on the organic layer by using a chemically amplified negative resist composition containing a silsesquoxane resin (A)
Data Source
AI summary
A method of forming a resist pattern of high aspect ratio excelling in etching resistance by the use of nanoimprint lithography. The method of forming a resist pattern by nanoimprint lithography comprises the steps of disposing organic layer (4) on support (1); providing resist layer (2) on the organic layer (4) with the use of chemical amplification type negative resist composition containing silsesquioxane resin (A); pressing light transmission allowing mold (3) with partial light shielding portion (5) against the resist layer (2) and thereafter carrying out exposure from the upside of the mold (3); and detaching the mold (3).