Silicone Temporary Adhesive for Clean Thin Wafer Debonding
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Solution Overview
Problem
Existing temporary adhesives used in semiconductor manufacturing lack sufficient durability, thermal stability, and cleanliness, limiting their applicability in high-temperature processes and leading to contamination during substrate peeling.
Innovation Solution
A silicone-based resin-containing temporary adhesive with a dissolution rate of 20 µm/min, heat resistance, and compatibility with high-temperature processes, allowing for uniform film formation and easy peeling, combined with a laser release agent for facilitated separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an organic resin film is used as a protective tape for the back surface, then flexibility is provided, but strength and heat resistance are inadequate
Solution Approach 1:
The patent employs a composite structure consisting of a silicon substrate providing mechanical strength and heat resistance, combined with a thin film layer providing flexibility and protective functions. This composite approach allows the system to simultaneously achieve both flexibility and high strength/heat resistance required for back surface processing
Solution Approach 2:
The patent introduces a temporary adhesive layer as an intermediary between the silicon substrate and the thin film. This adhesive layer acts as a mediator that enables the thin film to withstand high-temperature processes (up to 400°C) by providing strong bonding to the thermally stable silicon substrate, thereby resolving the heat resistance limitation of organic resin films
2Reliability
If a temporary adhesive layer is used to bond substrate to support, then durability is improved, but peeling difficulty increases
Solution Approach 1:
The patent utilizes parameter changes in the temporary adhesive layer's properties - specifically its dissolution characteristics. The adhesive is designed to maintain strong bonding at high temperatures during processing, then undergoes controlled dissolution in specific solvents (such as dimethylpropionamide or N-methyl-2-pyrrolidone) to enable easy peeling. This parameter change from bonded state to dissolved state resolves the contradiction between durability and peeling ease
Solution Approach 2:
The temporary adhesive layer is designed as a disposable component that is intentionally discarded after serving its protective function. The layer is dissolved in solvent to remove the bonded substrate from the support structure, allowing recovery of the processed substrate while the adhesive is discarded as soluble residue, thus enabling both strong bonding during processing and easy separation afterward
3Strength
If high temperature exposure is used for processing, then bonding strength is improved, but thermal oxidation occurs and cleanability deteriorates
Solution Approach 1:
The patent employs an inert silicon substrate as the base material for the temporary adhesive system. Silicon's inherent resistance to thermal oxidation creates a chemically inert environment that protects the adhesive layer from degradation during high-temperature processing (up to 400°C), thereby maintaining bonding strength while preventing thermal oxidation and contamination
Solution Approach 2:
The temporary adhesive layer is designed as a short-lived, disposable component that is intentionally sacrificed during the process. Rather than attempting to preserve the adhesive layer indefinitely, the system uses a low-cost, easily removable adhesive that can withstand high temperatures temporarily, then is dissolved in solvent to eliminate contamination, thus resolving the conflict between high-temperature bonding strength and cleanability
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 uniform thin wafer fabrication with high film thickness uniformity, easy peeling, and effective adhesive removal without substrate contamination, enhancing semiconductor substrate productivity.
Implementation Method 1
dissolving the temporary adhesive layer remaining on the semiconductor substrate or the support in a dimethylpropionamide solution at 50°C containing 3% by mass of tetrabutylammonium fluoride
Data Source
AI summary
The present invention is a silicone-based resin-containing temporary adhesive containing a silicone-based resin, configured to temporarily adhere a semiconductor substrate to a support, in which a dissolution rate of a temporary adhesive layer formed of the temporary adhesive is 20 µm/min or more, as measured by attaching the semiconductor substrate to the support via the temporary adhesive layer, performing heating at 260°C for 2 hours and then peeling off the semiconductor substrate and the support, and then dissolving the temporary adhesive layer remaining on the semiconductor substrate or the support in a dimethylpropionamide solution at 50°C containing 3% by mass of tetrabutylammonium fluoride. Thus, the present invention provides a silicone-based resin-containing temporary adhesive configured to facilitate bonding between a support and a substrate, enable a heavily stepped substrate to be formed with a uniform film thickness, exhibit high compatibility with steps of forming a TSV and forming a wiring on the wafer back surface, allow easy peeling of the substrate from the support, and enable effective removal of an adhesive layer without contaminating the substrate, thereby enhancing productivity of thin substrates.