Lactone Copolymer Resist Composition for Wide Depth of Focus
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Solution Overview
Problem
Current radiation-sensitive resin compositions for microfabrication face challenges in achieving high sensitivity, resolution, and wide depth of focus for both line-and-space and isolated space patterns, while maintaining minimal line width changes due to temperature fluctuations, which is complex due to the intricate relationship between the resin component's chemical structure and resist characteristics.
Innovation Solution
A lactone-containing copolymer with specific non-bridged and bridged lactone structures, combined with a photoacid generator, is used to form a radiation-sensitive resin composition that is insoluble in alkali but becomes alkali-soluble upon acid action, ensuring high transparency and stability in forming precise resist patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional radiation-sensitive resin compositions are used, then basic resist properties such as sensitivity and resolution can be achieved, but it is extremely difficult to simultaneously achieve wide common depth of focus, minimal line width change due to temperature fluctuation, and high precision pattern formation
Solution Approach 1:
The patent uses a composite resin composition comprising a copolymer with specific non-bridged lactone units (10-50 mol%), bridged lactone units (30-70 mol%), and carboxyl-containing polymer units (10-50 mol%). This multi-component composite structure enables simultaneous achievement of wide common DOF, temperature stability, and high precision patterning by combining the complementary properties of each polymer component.
Solution Approach 2:
The patent optimizes specific parameters including the mol% composition ranges of each polymer unit, the glass transition temperature (Tg) of the copolymer (50-150°C), and the weight average molecular weight (10,000-100,000). These parameter optimizations enable the resin to exhibit stable resist properties across varying conditions while maintaining high manufacturing precision.
2Ease of manufacture
If the resin component structure is simplified, then ease of manufacture and development improve, but the ability to achieve multiple required performances (wide common DOF, temperature stability, high resolution) simultaneously becomes extremely difficult
Solution Approach 1:
The patent defines specific parameter ranges for reliable resist performance: copolymer Tg between 50-150°C, weight average molecular weight of 10,000-100,000, and specific mol% compositions. These parameter specifications provide clear development guidelines while ensuring consistent reliability across different resin formulations.
Solution Approach 2:
The patent assigns specific functional roles to different polymer components: non-bridged lactone units provide solubility control, bridged lactone units enhance mechanical stability, and carboxyl-containing units enable chemical amplification. This functional differentiation allows each component to be optimized independently while contributing to overall system reliability.
3Device complexity
If a single type of lactone structure is used in the copolymer, then the resin composition becomes simpler, but the common depth of focus for both line-and-space and isolated space patterns cannot be sufficiently widened
Solution Approach 1:
The patent combines two distinct lactone structures (non-bridged and bridged) in specific proportions within the copolymer. The non-bridged lactone units (10-50 mol%) provide one set of properties while bridged lactone units (30-70 mol%) provide complementary properties, together achieving wide common DOF for both line-and-space and isolated space patterns.
Solution Approach 2:
The patent segments the lactone component into two distinct functional segments: non-bridged lactone units and bridged lactone units. This segmentation allows each segment to contribute differently to the overall resist performance, with non-bridged units affecting solubility and bridged units affecting structural stability, thereby widening the common DOF.
4Productivity
If the resin composition is optimized for high sensitivity and resolution, then basic resist properties improve, but line width change due to bake temperature fluctuation increases
Solution Approach 1:
The patent optimizes the glass transition temperature (Tg) of the copolymer to be within 50-150°C, which balances sensitivity and thermal stability. This Tg optimization ensures that the resin maintains its physical properties during bake processes, minimizing line width changes while preserving high sensitivity and resolution.
Solution Approach 2:
The patent uses a composite of copolymer and carboxyl-containing polymer where the copolymer provides thermal stability through its specific lactone structure and Tg range, while the carboxyl-containing polymer enhances sensitivity through chemical amplification. This composite structure resolves the trade-off between sensitivity and thermal 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 composition exhibits excellent sensitivity, resolution, and a wide common depth of focus, with minimal line width changes and no pattern destruction, even under temperature fluctuations, enabling the stable formation of high-precision resist patterns.
Implementation Method 1
a photoacid generator which generates an acid upon irradiation with radiations
Implementation Method 2
chemical amplification effect between a resin component having an acid-dissociable functional group and a photoacid generator
Implementation Method 3
insoluble or scarcely soluble in alkali, but becomes alkali-soluble by the action of an acid
Data Source
AI summary
A radiation-sensitive resin composition excelling in basic properties as a resist such as sensitivity, resolution, and the like, having a wide depth of focus (DOF) to both a line-and-space pattern and an isolated space pattern, and exhibiting a minimal line width change due to fluctuation of a bake temperature, and having a small line width limit in which the line pattern destroying phenomenon does not occur, and a lactone-containing copolymer useful as a resin component of the composition are provided.The lactone-containing copolymer is represented by a copolymer of the following compounds (1-1), (2-1), and (3-1).The radiation-sensitive resin composition comprises (a) the lactone-containing copolymer and (b) a photoacid generator.