Photosensitive Resin Composition for i-line Lithography Taper Angle Control

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Solution Overview

Problem

Existing photosensitive negative resin compositions used in photolithographic processes for forming fine structures, such as those in MEMS, often exhibit variability in taper angles of ejection orifices, leading to inconsistent reproducibility, particularly when using an i-line light source.

Innovation Solution

A photosensitive negative resin composition comprising an epoxy-group-containing compound, a first onium salt with specific cation and anion structures that enhance photosensitivity and acid generation, and a second onium salt that acts as a quencher to stabilize the polymerization process, ensuring consistent three-dimensional form reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a polyfunctional epoxy resin and cationic polymerization initiator are used to form a fine structure by photolithography, then the structure can be formed, but the taper angle of the ejection orifice varies in chip or wafer leading to poor reproducibility

Engineering Contradiction:
Improvetaper angle consistencyVSAvoidreproducibility of three-dimensional form
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the photosensitive resin composition by introducing a specific onium salt with a cation portion containing at least two oxygen atoms and a particular anion structure. This parameter change in the chemical composition leads to improved control over the polymerization process, resulting in consistent taper angles and high reproducibility of three-dimensional forms across chips and wafers

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photosensitive resin composition by combining an epoxy-group-containing compound with a specifically structured onium salt. This composite material system synergistically controls the polymerization process to achieve reduced dispersion and excellent reproducibility of fine structures, particularly when using an i-line light source

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If a negative photosensitive resin is used to form complicated structures like ejection orifices, then the structures can be created, but the taper angle dispersion is high and reproducibility is poor

Engineering Contradiction:
Improvestructure formation capabilityVSAvoidtaper angle precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent modifies the chemical parameters of the photosensitive resin by incorporating an onium salt with specific structural features (cation portion with at least two oxygen atoms, specific anion structure). This parameter change enables precise control of the polymerization process, achieving both the ability to form complicated structures and the precision required for consistent taper angles

Inventive Principle:
Principle #35Parameter changes

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 stable and reproducible formation of fine structures with reduced dispersion, particularly under i-line photolithography, by synergistically controlling the polymerization process through the interaction of the onium salts and epoxy groups, resulting in high reproducibility and accuracy of three-dimensional forms.

Implementation Method 1

a first onium salt containing a cation portion structure represented by (b1) and an anion portion structure represented by (b2)... a second onium salt containing a cation portion structure represented by (c1) and an anion portion structure represented by (c2)... when a photolithographic process is applied thereto

Methodology Applied
Scientific EffectPhotodissociation: Photodissociation

Implementation Method 2

a photosensitive negative resin composition comprising (a) an epoxy-group-containing compound, (b) a first onium salt... and (c) a second onium salt... excellent reproducibility of a three-dimensional form

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP2628050B1Photosensitive negative resin composition
Publication Date: 2015.09.09 CANON KK
  • EP2628050B1 patent drawingFigure 1~2
  • EP2628050B1 patent drawingFigure 3A~3F
  • EP2628050B1 patent drawingFigure 4A~4F

AI summary

The invention provides a photosensitive negative resin composition containing (a) an epoxy-group-containing compound, (b) a first onium salt containing a cation portion structure represented by (b1) and an anion portion structure represented by (b2), and (c) a second onium salt containing a cation portion structure represented by (c1) and an anion portion structure represented by (c2).