Polyimide Copolymer High-Temperature Solubility
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Solution Overview
Problem
Polyimide materials used in semiconductor and display industries face challenges with solubility issues at high temperatures (350° C. and above) during metal oxide patterning processes, limiting their application in high-temperature deposition processes.
Innovation Solution
A polyimide copolymer with specific molecular structures, represented by formulas (I) and (II), is developed, which maintains solubility in organic solvents after high-temperature processing, allowing for the formation of a temporary protective film that can endure temperatures above 350° C. and be easily removed to create patterned metal oxide layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soluble polyimide is used in the lift-off process, then the polyimide can be dissolved in solvents at temperatures below 350°C, but it becomes insoluble at high temperatures (350°C and above) due to molecular chain stacking and free volume reduction
Solution Approach 1:
The patent introduces terminal functional groups (carboxyl, hydroxyl, or amine groups) at the ends of the polyimide molecular chains. These terminal groups maintain solubility by preventing molecular chain stacking even at high temperatures (350°C and above), thereby changing the thermal-solubility parameter of the polyimide material to enable use in high-temperature metal oxide deposition processes
Solution Approach 2:
The patent creates a composite polyimide structure by combining the base polyimide chain with terminal functional groups. This composite structure integrates the thermal stability of polyimide with the solubility enhancement provided by the terminal groups, resulting in a material that maintains both high-temperature resistance and solvent dissolvability
2Temperature
If conventional polyimide is used as a temporary protective film, then it provides thermal stability, but it cannot be easily removed after high-temperature processing due to insolubility
Solution Approach 1:
The patent modifies the polyimide structure by adding terminal functional groups that remain soluble in organic solvents even after high-temperature exposure. This parameter change enables the protective film to be easily removed through solvent dissolution after metal oxide deposition, solving the removability issue while maintaining thermal stability
3Reliability
If the process temperature is limited to below 350°C to maintain polyimide solubility, then soluble polyimide can be used, but high-temperature metal oxide deposition processes cannot be performed
Solution Approach 1:
The patent changes the thermal-solubility parameter of polyimide by introducing terminal functional groups, expanding the acceptable process temperature range from below 350°C to 350°C and above. This enables the material to be used in high-temperature metal oxide deposition processes while maintaining solubility for subsequent film removal
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 polyimide copolymer ensures thermal stability and high solubility, enabling a simple and efficient metal oxide patterning process by forming a temporary protective film that can withstand high temperatures and be dissolved post-processing, facilitating the creation of patterned metal oxide layers with excellent characteristics.
Implementation Method 1
during a high-temperature (350° C. and above) process, the molecular chains of the polyimide will mutually stack and tend to lower the energy and then shrink free volume
Implementation Method 2
mixing a diamine and a dianhydride together to form a polyimide precursor; mixing an aniline and the polyimide precursor together to form a reaction mixture; and imidizing the reaction mixture to prepare a polyimide copolymer
Implementation Method 3
removing the patterned polyimide layer to form a patterned metal oxide layer
Data Source
AI summary
A polyimide copolymer represented by formula (I) or formula (II) is provided.In formula (I) or formula (II), B is a cycloaliphatic group or aromatic group, A is an aromatic group, R is hydrogen or phenyl, and m and n are 20-50. The invention also provides a method for fabricating a patterned metal oxide layer.