Negative-Type Photosensitive Resin for Low-Temperature Imidization
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Solution Overview
Problem
Existing photosensitive resin compositions using polyimide precursors face challenges in achieving imide ring-closing reactions at low temperatures, suffer from poor chemical resistance and corrosion, and have stability issues during storage and patterning, which are critical for high-density mounting technologies like chip-size packages and three-dimensional stacking.
Innovation Solution
A negative-type photosensitive resin composition incorporating a polymer compound with a polyimide precursor structure, a photopolymerization initiator, and an organic compound represented by specific general formulas, allowing imide ring-closing reactions at 200°C or lower, enhancing storage stability and chemical resistance, and enabling fine patterning without pattern deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high temperature imidization treatment (>300°C) is performed to obtain target polyimide coating, then imide ring-closing reaction is completed, but base substrate is limited, copper wiring oxidizes, and thermal damage risk increases
Solution Approach 1:
The patent introduces a photopolymerization initiator system that enables the imidization reaction to proceed at significantly lower temperatures (below 300°C) by changing the reaction mechanism from thermal to photo-initiated. This parameter change in reaction initiation method directly resolves the contradiction between achieving complete imidization and preventing substrate/wiring damage.
Solution Approach 2:
The patent replaces the thermal energy-based imidization process with a photochemical initiation system. By using photopolymerization initiators that absorb specific wavelengths of light to trigger the imidization reaction, the mechanical/thermal system is substituted with an optical-chemical system, enabling low-temperature curing that protects the substrate and copper wiring.
2Ease of manufacture
If polyimide precursor composition is stored before imidization, then application and patterning can be performed, but cyclization reaction proceeds during storage causing gelation and poor storage stability
Solution Approach 1:
The patent incorporates the photopolymerization initiator and necessary components into the composition in advance, but the actual imidization reaction is postponed until photo-irradiation is applied. This preliminary preparation allows the composition to be stored in a stable, unreacted state while maintaining all necessary components for subsequent low-temperature curing when needed.
Solution Approach 2:
The patent creates a composition where the imidization reaction can be locally activated by photo-irradiation only in the exposed areas. The photopolymerization initiator is distributed throughout the composition, but the reaction occurs only where light is applied, allowing selective curing that prevents bulk gelation during storage while enabling localized patterning.
3Manufacturing precision
If conventional photosensitive resin composition is used for fine patterning, then pattern formation is achieved, but pattern deformation occurs due to thermal flow in curing reaction
Solution Approach 1:
The patent replaces the thermal curing process with photo-initiated imidization. By using photopolymerization initiators that activate the imidization reaction through light absorption rather than heat, the thermal field is eliminated during curing. This substitution prevents thermal flow and the associated pattern deformation, maintaining the precision of the exposed pattern geometry.
Solution Approach 2:
The patent changes the curing temperature parameter from conventional high temperatures (>300°C) to low temperatures enabled by photo-initiation. This parameter change in curing temperature directly prevents thermal flow phenomena that cause pattern deformation, while still achieving complete imidization through the photochemical reaction pathway.
4Temperature
If imidazoles are added as imidization catalyst to enhance ring-closing reaction, then low temperature imidization is achieved, but storage stability deteriorates due to gelation and glass transition temperature decreases
Solution Approach 1:
The patent substitutes chemical catalysts (imidazoles) with a photochemical initiation system. Instead of using imidazole compounds that lower the glass transition temperature and cause gelation during storage, the patent employs photopolymerization initiators that activate imidization only upon light exposure. This substitution eliminates the storage stability issues while achieving low-temperature curing.
Solution Approach 2:
The patent introduces photopolymerization initiators as intermediary substances that mediate the imidization reaction. These initiators remain dormant during storage and only become active when exposed to light of appropriate wavelength. This intermediary mechanism enables low-temperature imidization without the adverse effects of permanent chemical catalysts like imidazoles.
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 enables low-temperature curing with improved stability, chemical resistance, and high glass transition temperature, facilitating fine patterning and reliable interlayer insulating films and surface protecting films for electronic components.
Implementation Method 1
a photopolymerization initiator
Implementation Method 2
enables imide ring-closing reactions at 200°C or lower
Data Source
AI summary
A negative-type photosensitive resin composition, including: (A) a polymer compound including a polyimide precursor structure; (C) a photopolymerization initiator; (D) an organic compound represented by the following general formula (1); and (E) a solvent. This can provide: a photosensitive resin composition that allows an imide ring-closing reaction at low temperature, that has excellent stability of the composition, that uses a polyimide precursor that enables fine patterning, and that can impart resistance against chemicals after curing. In addition, an object of the present invention is to provide: a patterning process using the above photosensitive resin composition; an interlayer insulating film including a cured coating formed by curing the photosensitive resin composition; and a semiconductor device.