Negative Photosensitive Composition for SAW Filter Pattern Resolution
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Solution Overview
Problem
Existing negative photosensitive compositions used in forming hollow sealing structures for electronic parts, such as SAW filters, face challenges in achieving fine pattern sizes due to insufficient curing at the semiconductor wafer interface, leading to defective pattern shapes.
Innovation Solution
A negative photosensitive composition comprising a novolak-type polyfunctional aromatic epoxy resin and a trifunctional epoxy monomer, combined with a sulfonium salt, is used, with a specific mass ratio to enhance pattern rectangularity and sensitivity, allowing for improved pattern formation through selective exposure and development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If reactivity between epoxy groups is increased to make the pattern size finer, then pattern resolution is improved, but curing at the semiconductor wafer interface becomes insufficient
Solution Approach 1:
The patent changes the chemical parameters of the epoxy composition by specifying a particular ratio of diglycidyl ether of bisphenol F to novolak-type polyfunctional aromatic epoxy resin (5/5 to 8/2 mass ratio), and selecting specific cationic polymerization initiators. This parameter optimization enables fine pattern formation while maintaining adequate curing at the semiconductor wafer interface, resolving the contradiction between pattern resolution and curing completeness.
Solution Approach 2:
The patent uses a composite epoxy system combining diglycidyl ether of bisphenol F and novolak-type polyfunctional aromatic epoxy resin in specific proportions, along with multiple cationic polymerization initiators. This composite material approach allows the composition to achieve both high reactivity for fine patterning and sufficient curing depth at the interface, simultaneously improving pattern resolution and curing completeness.
2Manufacturing precision
If reactivity between epoxy groups is increased to make the pattern size finer, then pattern size is reduced, but pattern shape becomes defective
Solution Approach 1:
The patent optimizes the chemical composition parameters, specifically the mass ratio of diglycidyl ether of bisphenol F to novolak-type polyfunctional aromatic epoxy resin (5/5 to 8/2) and the selection of cationic polymerization initiators. This parameter control enables the formation of fine patterns with proper shape and rectangularity, preventing defects that would otherwise occur with high reactivity compositions.
3Manufacturing precision
If sensitivity is improved for fine pattern formation, then pattern resolution is enhanced, but curing uniformity deteriorates
Solution Approach 1:
The patent employs a composite system combining diglycidyl ether of bisphenol F, novolak-type polyfunctional aromatic epoxy resin, and multiple cationic polymerization initiators. This composite formulation achieves high sensitivity for fine pattern formation while maintaining uniform curing throughout the photosensitive film, including at the semiconductor wafer interface, thus resolving the contradiction between sensitivity and curing uniformity.
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 achieves favorable sensitivity and improved rectangularity of pattern shapes, addressing the issue of defective patterns by ensuring adequate curing and resolution in the formation of fine-sized features.
Implementation Method 1
the photosensitive film is selectively exposed to radiation such as light and electron beams
Implementation Method 2
a photosensitive composition containing an epoxy group-containing resin having two or more epoxy groups in one molecule and various cationic polymerization initiators
Data Source
AI summary
A negative photosensitive composition including a novolak-type polyfunctional aromatic epoxy resin (Ap), a trifunctional epoxy monomer (Am), and a sulfonium salt represented by Formula (I0). A mass ratio of (Am)/(Ap) is 5/5 to 8/2. In Formula (I0), R1 and R2 represent an aryl group, a heterocyclic hydrocarbon group, or an alkyl group. R3 to R5 are an alkyl group, a hydroxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic hydrocarbon group, an aryloxy group, a hydroxy(poly)alkyleneoxy group, or a halogen atom; k is an integer of 0 to 4, m is an integer of 0 to 3, and n is an integer of 1 to 4; L is —S—, —O—, —SO—, —SO2—, or —CO— and X− represents a monovalent polyatomic anion