Pellicle Tackifier Composition for Low-Outgas Lithography Protection
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Solution Overview
Problem
Existing pellicles used in lithography processes for semiconductor devices generate significant outgas and tackifier residues due to the decomposition of tackifier components under short-wavelength exposure light, leading to haze and stability issues.
Innovation Solution
A pellicle comprising a tackifier layer made from a (meth)acrylic tackifier with a polymer (A) having a structural unit derived from a (meth)acrylate and a side chain with a carbon-carbon multiple bond, combined with a radical polymerization initiator (B), which enhances solution stability and reduces outgas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicone tackifier is used, then the tackifier provides good adhesion, but it generates a large amount of outgas under short-wavelength exposure light causing significant haze
Solution Approach 1:
The patent changes the chemical composition parameters of the tackifier by using a (meth)acrylic polymer with specific molecular weight (10,000-1,000,000 g/mol) and incorporating carbon-carbon multiple bond-containing groups in the side chain. This parameter change reduces outgas generation while maintaining adhesion properties under short-wavelength exposure light.
Solution Approach 2:
The patent creates a composite tackifier system combining (meth)acrylic polymer with carbon-carbon multiple bond-containing groups and radical polymerization initiator. This composite material structure provides both adhesion and suppressed outgas generation by utilizing the specific chemical interactions and stability of the composite components.
2Strength
If a (meth)acrylic tackifier with epoxy or isocyanate crosslinking agent is used, then the tackifier achieves crosslinking, but the resin composition shows instability due to high reactivity of the crosslinking agent
Solution Approach 1:
The patent extracts and removes the problematic epoxy or isocyanate crosslinking agents from the resin composition. Instead, it uses a radical polymerization initiator that remains stable in the composition while still enabling crosslinking through a different mechanism, thus eliminating the instability issue.
Solution Approach 2:
The patent replaces the chemical crosslinking mechanism involving highly reactive epoxy or isocyanate compounds with a radical polymerization mechanism. This substitution maintains the crosslinking function while improving composition stability by avoiding the high reactivity and instability associated with the previous crosslinking agents.
3Ease of operation
If the tackifier layer is designed for peelable attachment, then the pellicle can be removed from the mask, but it generates tackifier residues after peeling-off
Solution Approach 1:
The patent changes the molecular weight parameter of the (meth)acrylic polymer to a specific range (10,000-1,000,000 g/mol) and incorporates carbon-carbon multiple bond-containing groups. These parameter changes modify the polymer's properties to enable clean peeling without residues while maintaining peelable attachment functionality.
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 solution provides a pellicle with minimal tackifier residues and suppressed outgas generation, ensuring high stability and effective protection of lithography masks during short-wavelength exposure.
Implementation Method 1
a (meth)acrylic tackifier which is a solidified resin composition comprising polymer (A) and radical polymerization initiator (B)
Implementation Method 2
Such short-wavelength light have high energy and, therefore, tackifier components are likely to decompose during light exposure
Data Source
AI summary
Task of the present invention is to provide a tackifier solution having high solution stability and also provide, by using such a tackifier solution, a pellicle having only few tackifier residues and exhibiting reduced outgas generation. Present invention is a pellicle comprising a pellicle frame, a pellicle membrane stretched over an end surface of one opening of the pellicle frame, and a tackifier layer provided on an end surface of the other opening of the pellicle frame, wherein the tackifier layer contains a (meth)acrylic tackifier which is a solidified resin composition comprising a polymer (A) and a radical polymerization initiator (B), the polymer (A) having a structural unit derived from a (meth)acrylate and a side chain consisting of a carbon-carbon multiple bond-containing group.