Positive Photosensitive Polyimide Resin Composition for High-Resolution Patterning
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Solution Overview
Problem
Current positive photosensitive resin compositions for polyimide films face challenges such as insufficient thermal resistance, transparency, and resolution, particularly when developed using aqueous alkali solutions, and often require halogen-containing or toxic compounds for flame retardance, limiting their application in high-performance electronic components.
Innovation Solution
A positive photosensitive resin composition combining a polyimide precursor with a norbornane skeleton, a vinyl ether compound, and a photoacid generating agent, which can be developed in an aqueous alkali metal carbonate solution, forming high-resolution patterns with excellent thermal resistance and transparency without halogen or antimony compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polyimide precursors are used for positive photosensitivity, then the structure is restricted to particular structures only, but sufficient resolution cannot be achieved and film shrinkage occurs
Solution Approach 1:
The invention divides the polyimide precursor structure into modular components: a core polyimide backbone and separately attachable photosensitive groups (such as diazonaphthoquinone, naphthoquinone imide, or sultone groups). This segmentation allows the photosensitive function to be added without restricting the base polyimide structure, enabling high resolution patterning while maintaining structural flexibility and preventing film shrinkage.
Solution Approach 2:
The invention creates composite polyimide structures by combining conventional polyimide precursors with grafted photosensitive groups. This composite approach allows the material to exhibit both the desirable properties of the base polyimide (thermal resistance, mechanical strength) and the photosensitivity required for high resolution patterning, without the limitations of either component alone.
2Ease of operation
If polyimide precursors with high alkali solubility are used, then development is easier, but sufficient resolution cannot be achieved
Solution Approach 1:
The invention applies local quality by creating regions of different solubility within the polyimide film. The photosensitive groups are strategically positioned to undergo chemical changes upon exposure, creating locally modified zones that become soluble in alkali developers. This localized solubility change enables both easy development of exposed areas and maintenance of high resolution, as only the intended pattern areas dissolve.
3Reliability
If halogen-containing compounds are used for flame retardance, then flame retardance is improved, but environmental safety and handling are worsened
Solution Approach 1:
The invention replaces persistent halogen-containing flame retardants with alternative flame retardant mechanisms that do not require toxic additives. The polyimide structure itself provides inherent flame resistance through its aromatic backbone and imide rings, eliminating the need for halogenated compounds and improving environmental safety while maintaining fire safety performance.
4Temperature
If alicyclic polyimide precursors are used, then thermal resistance is improved, but film formation is unsatisfactory
Solution Approach 1:
The invention modifies processing parameters to achieve satisfactory film formation with alicyclic polyimide precursors. By optimizing coating conditions, solvent selection, and thermal processing parameters, the invention enables proper film formation while maintaining the high thermal resistance provided by the alicyclic structure. The photosensitive group grafting also facilitates controlled processing.
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 the formation of polyimide films with high thermal resistance, transparency, and low dielectric constant, suitable for microfabrication and flexible printed circuit boards, offering improved handling and environmental safety.
Implementation Method 1
a photosensitizer (C) generating acid upon irradiation of an actinic ray
Implementation Method 2
dissolving only the exposed part of the coating film with an aqueous solution of alkali metal carbonate, to develop a positive pattern
Implementation Method 3
thermally treating the developed positive pattern to form a positive pattern containing the polyimide
Data Source
AI summary
A positive photosensitive resin composition containing 100 parts by weight of a polyimide precursor (A) having a constituent unit represented by the formula (1), 15 to 25 parts by weight of a crosslinking agent (B) represented by the formula (2), and 2 to 5 parts by weight of a photosensitizer (C) generating acid upon irradiation of an actinic ray:wherein m is an integer of 1 or greater, and R is an aromatic group or an aliphatic group having a valency of 1 or higher. The positive photosensitive resin composition can be developed by using an aqueous solution of alkali metal carbonate, is capable of forming micropatterns, and has excellent thermal resistance and the like. A method for forming a positive pattern, and uses thereof are also provided.