Cycloaliphatic Ester Resins for Lithographic Resolution and LER
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Solution Overview
Problem
Current photolithographic resins for high-density semiconductor integration face challenges in achieving improved sensitivity, resolution, and line edge roughness while maintaining fundamental properties such as pattern shape, dry etching resistance, and heat resistance, especially at the 20 nm scale and beyond.
Innovation Solution
A mixture of cycloaliphatic ester compounds represented by specific general formulae, used as repeating units in (meth)acrylic copolymers, which are synthesized through a reaction between an adamantane compound and a glycidyl (meth)acrylate compound, along with a photoacid generator, to form a photosensitive resin composition that enhances sensitivity, resolution, and line edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single type of repeating unit is used in the functional resin, then the resin structure is simple and easy to manufacture, but it cannot satisfy all required properties including etching resistance, substrate adhesion, transparency, and development rate
Solution Approach 1:
The patent employs copolymerization of multiple repeating units (first, second, and third types) within a single polymer chain to create a composite functional resin. Each repeating unit contributes specific properties: the first provides etching resistance, the second provides substrate adhesion, and the third provides transparency and development characteristics. This composite structure allows all required resist properties to be satisfied simultaneously while maintaining a relatively simple copolymerization process.
2Reliability
If multiple types of repeating units are used to improve etching resistance and other properties, then the resist performance is improved, but the resin composition becomes more complex and requires blending with photoacid generators and solvents
Solution Approach 1:
The patent designs a multi-functional copolymer where different repeating units perform multiple roles. The hydroxyl-containing repeating units provide both etching resistance and contribute to the chemical amplification mechanism. The copolymer structure itself serves as both the base resin and the vehicle for incorporating photoacid generators. This multi-functionality reduces the need for separate additives and simplifies the overall composition while maintaining high resist performance.
3Manufacturing precision
If alcoholic hydroxyl group content is increased to improve sensitivity and resolution, then lithographic performance is enhanced, but the resin may lose other fundamental properties such as pattern shape control and etching resistance
Solution Approach 1:
The patent distributes hydroxyl-containing repeating units locally within the copolymer chain rather than uniformly throughout. By controlling the copolymerization composition and sequence, regions with higher hydroxyl content are created to enhance sensitivity and resolution where needed, while other regions maintain properties for pattern shape control and etching resistance. This local optimization allows simultaneous achievement of high resolution and reliable pattern formation.
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 cycloaliphatic ester compounds improve the performance of photolithographic resins by achieving better sensitivity, resolution, and line edge roughness without compromising the essential properties required for high-density semiconductor integration, making them suitable for future lithographic techniques.
Implementation Method 1
a (meth)acrylic copolymer, which comprises at least one of the following general formulae (6) to (8) as a repeating unit
Implementation Method 2
a photoacid generator and further containing several types of additives
Data Source
AI summary
The present invention provides, as a chemically amplified resist, a well-balanced resist or compound which results in improved sensitivity, resolution and line edge roughness (LER) without impairing the fundamental physical properties required as a resist (e.g., pattern shape, dry etching resistance, heat resistance). A mixture of cycloaliphatic ester compounds represented by general formulae (1) to (3), and a process for preparation thereof, as well as a (meth)acrylic copolymer comprising the cycloaliphatic ester compounds of general formulae (1) to (3) and a photosensitive resin composition thereof are provided.