Photoresist Stripping Solution for Selective Dissolution
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Solution Overview
Problem
Current resin stripping solutions for microelectronic component integration processes are ineffective in completely dissolving semi-novolac resins at temperatures below 100°C, leading to residual debris and potential defects, and often compromise the integrity of exposed metals like copper and aluminum.
Innovation Solution
A formulation using two ether or polyether solvents as the principal solvent, combined with an acid and minimal water content, which enables complete dissolution of photoresists at temperatures between 40 and 100°C while ensuring compatibility with metal interconnections and dielectrics, allowing for efficient recirculation and minimal substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional resin stripping solutions are used, then resin can be removed at high temperatures, but the solutions fail to completely dissolve semi-novolac resins at temperatures below 100°C, leaving residual debris
Solution Approach 1:
The patent modifies the chemical composition parameters of the stripping solution by incorporating specific ether solvents (diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether) in optimized concentrations (70-95% v/v), combined with controlled amounts of acid (0.1-5% v/v) and water (0.1-30% v/v). This parameter optimization enables complete photoresist dissolution at reduced temperatures (40-100°C) while maintaining solution stability and effectiveness.
Solution Approach 2:
The patent creates a composite chemical formulation combining multiple solvent types (ether solvents, acids, and water) with complementary functions. The ether solvents provide photoresist swelling and dissolution capability, the acid enhances polymer matrix breakdown, and minimal water content prevents metal corrosion while maintaining solution homogeneity. This composite approach achieves complete dissolution at lower temperatures than conventional single-solvent systems.
2Productivity
If strong chemical agents are used to strip resin, then resin removal effectiveness improves, but the integrity of exposed metals such as copper and aluminum is compromised
Solution Approach 1:
The patent uses ether solvents as intermediary substances that mediate between the photoresist polymer matrix and the metal substrates. These solvents swell and dissolve the photoresist through hydrogen bonding and dipole interactions without directly attacking metal surfaces. The minimal water content (0.1-30% v/v) further reduces chemical aggressiveness while maintaining dissolution effectiveness, creating a buffered chemical environment that protects metals from corrosion.
Solution Approach 2:
The patent optimizes the concentration parameters of corrosive components by limiting acid content to 0.1-5% v/v and water content to 0.1-30% v/v, while maintaining high ether solvent content (70-95% v/v). This parameter control reduces the chemical potential for metal attack while preserving photoresist dissolution capability through the dominant ether solvent system.
3Manufacturing precision
If photoresist stripping is performed, then surface quality improves, but the stripping solution requires frequent replacement due to particulate accumulation
Solution Approach 1:
The patent formulates a stripping solution with enhanced stability and complete dissolution capability that prevents particulate precipitation during extended use. The optimized ether solvent composition (70-95% v/v of diethylene glycol monobutyl ether and/or dipropylene glycol monomethyl ether) maintains photoresist in complete solution form, preventing filter clogging and solution degradation. This enables continuous recirculation and extends solution lifespan, maintaining surface quality consistency over prolonged operation.
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 achieves complete dissolution of photoresists without damaging exposed metals, facilitating optimal surface quality and enabling the recirculation of stripping solutions, thus improving the performance and reliability of microelectronic component fabrication.
Implementation Method 1
A formulation using two ether or polyether solvents as the principal solvent, combined with an acid and minimal water content, which enables complete dissolution of photoresists at temperatures between 40 and 100°C
Implementation Method 2
A formulation using two ether or polyether solvents as the principal solvent, combined with an acid
Data Source
Figure 1~2
AI summary
The present invention relates to the formulation of a chemical, comprised of an ether solvent as the principal solvent, an ether or non-ether cosolvent, an acid, optionally a surfactant and optionally a corrosion inhibitor, dedicated to the complete and selective stripping by pure dissolution of photoresists (novolac and semi-novolac) of all thicknesses used in microelectronic component integration processes. Said solution is optimized to dissolve the polymer matrix while ensuring and protecting the physicochemical integrity of exposed materials such as metal interconnections (copper, aluminum), dielectrics (SiO2, MSQ, etc.) and adhesion and diffusion barriers (TiN, Ti, Ta, TaN, etc.). Furthermore, the singular cleaning properties and performance characteristics of these solutions make it possible to envisage the use thereof in a variety of industrial applications such as single wafer, batch, immersion and/or spray by simple adjustment of process time and temperature.