Positive Tone Photopatternable Silicone via Inversion
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Solution Overview
Problem
Current photopatternable silicone compositions are negative tone, where exposed areas cure and become non-removable, while unexposed areas are removed, whereas a positive tone composition is needed where exposed areas remain removable and unexposed areas cure quickly, within minutes.
Innovation Solution
A composition comprising polysiloxane with alkenyl groups, silane crosslinker with silicon-hydrogen bonds, hydrosilylation catalyst, and photolatent amine generator, which is exposed to UV or electron beam irradiation through a mask, allowing the uncured portions to be removed after heating, while unexposed areas cure and become non-removable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If negative tone photopatternable silicone compositions are used, then exposed areas cure and become non-removable, but unexposed areas are removed requiring longer processing times
Solution Approach 1:
The patent inverts the conventional negative tone photopatternable silicone behavior by formulating a composition where exposed areas remain removable while unexposed areas cure. This is achieved by using a photolatent amine generator that becomes active upon UV or electron beam irradiation to catalyze the hydrosilylation reaction only in unexposed regions, thereby enabling positive tone patterning with rapid cure times on the order of minutes
2Productivity
If conventional photopatternable silicone compositions are used, then pattern formation is achieved, but cure times are on the order of hours
Solution Approach 1:
The patent changes the chemical parameters of the silicone composition by incorporating a photolatent amine generator and hydrosilylation catalyst system that enables rapid curing. The photolatent amine generator undergoes photochemical transformation upon irradiation to form a strong acid catalyst that accelerates the hydrosilylation reaction, reducing cure times from hours to minutes while ensuring complete curing through the efficient catalytic mechanism
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
Enables rapid curing of unexposed areas within minutes and maintains the removability of exposed areas, providing a positive tone photopatternable silicone layer with improved processing times and control over pattern formation.
Implementation Method 1
a photolatent amine generator; wherein the composition comprises no more than 5 wt % siloxane units having epoxy groups based on weight of composition solids
Implementation Method 2
a polysiloxane comprising alkenyl groups, (ii) a silane crosslinker comprising silicon-hydrogen bonds, (iii) a hydrosilylation catalyst
Data Source
AI summary
A method for producing a patterned silicone layer; said method comprising steps of: (a) depositing on a substrate a composition comprising: (i) a polysiloxane comprising alkenyl groups, (ii) a silane crosslinker comprising silicon-hydrogen bonds, (iii) a hydrosilylation catalyst, and (iv) a photolatent amine generator, to form an uncured resin; (b) exposing the uncured resin to ultraviolet light or electron beam irradiation through a mask to produce a patterned resin; (c) heating the patterned resin; and (e) removing at least a part of the uncured portion of the patterned resin to produce a final patterned silicone layer.