Polyimide Release Layer for UV Laser Lift-Off Debonding
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Solution Overview
Problem
In the fabrication of semiconductor devices, the use of adhesives during the grinding process can lead to warpage of semiconductor substrates, causing damage during peeling or releasing, and there is a need for a release layer with improved peeling properties and heat resistance to address these issues.
Innovation Solution
A polyimide precursor composition is developed, including an imide precursor formed from a diamine compound, a dianhydride compound, and a cyclic ether group-containing compound, which is used to create a polyimide film with enhanced heat resistance and debonding properties, suitable as a release layer for laser lift-off processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive is attached to the semiconductor substrate, then the substrate can be fixed during fabrication, but warpage occurs and damage happens during peeling or releasing
Solution Approach 1:
The patent introduces a release layer as a separate functional layer between the adhesive and the semiconductor substrate. This segmentation allows the adhesive to maintain strong bonding for fixation while the release layer provides a controlled peeling interface that prevents substrate damage during release operations.
Solution Approach 2:
The release layer acts as an intermediary layer between the adhesive and the semiconductor substrate. It mediates the bonding and peeling processes by providing a controlled interface that enables strong adhesion during fabrication while allowing damage-free peeling during release, thus resolving the contradiction between bonding strength and substrate integrity.
2Reliability
If a release layer is introduced to improve peeling properties, then damage during peeling is reduced, but the device structure becomes more complex
Solution Approach 1:
The release layer is designed to perform multiple functions: it provides peeling resistance to prevent substrate damage, maintains adhesion during fabrication processes, and enables controlled release when needed. By consolidating these functions into a single layer, the patent minimizes structural complexity while achieving the desired reliability improvements.
3Weight of moving object
If the semiconductor device is reduced in size and thickness for high integration, then device compactness is improved, but warpage and damage risks increase during fabrication
Solution Approach 1:
The release layer is introduced as a protective measure before the fabrication and peeling processes begin. It cushions the thin, vulnerable semiconductor substrate against warpage and damage during fabrication and subsequent peeling operations, enabling the device to maintain its reduced thickness and high integration while preserving fabrication stability.
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 film exhibits improved time-dependent stability, low viscosity, and high absorbance in the ultraviolet region, enabling effective debonding of semiconductor devices without physical or chemical damage, even under harsh storage conditions, and maintains high thermal stability and mechanical properties.
Implementation Method 1
The polyimide copolymer may be prepared by a condensation polymerization of an aromatic dianhydride and an aromatic diamine followed by an imidization
Implementation Method 2
a light transmittance at a wavelength of 308 nm measured at a thickness of 4,500 Å is 25% or less
Data Source
AI summary
A polyimide precursor composition according to an exemplary embodiment includes an imide precursor having an organic group derived from a cyclic ether group-containing compound. A polyimide film formed using the polyimide precursor composition has improved heat resistance and mechanical properties, and has high absorbance in a wavelength range in an ultraviolet region.