High-Pressure Solvent Debonding for Semiconductor Wafers
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Solution Overview
Problem
The challenge in semiconductor wafer thinning is the instability and susceptibility to breakage of ultra-thin wafers, which requires temporary bonding to a carrier for mechanical support, but existing debonding methods are inefficient and prone to defects, especially for high-throughput and low-cost volume production in 3D-IC wafer level packaging.
Innovation Solution
A method using high-pressure solvent streams or sprays to debond temporarily adhesive-bonded carrier-workpiece pairs, capable of dissolving adhesives at pressures ranging from 60 to 10000 psi, allowing for efficient separation and cleaning, particularly effective for semiconductor wafers, and enabling the use of recyclable thermoplastic adhesives to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional debonding methods are used for temporarily bonded carrier-workpiece pairs, then the process is simpler, but the productivity is low and defects such as wafer breakage occur frequently
Solution Approach 1:
The patent replaces traditional mechanical debonding methods (such as mechanical peeling or scraping) with a chemical dissolution approach using high-pressure solvent streams. The solvent chemically dissolves the temporary adhesive bonding the carrier to the workpiece, enabling defect-free separation without mechanical stress that could cause ultra-thin wafer breakage, while maintaining high throughput through automated high-pressure solvent delivery systems
Solution Approach 2:
The patent employs high-pressure hydraulic or pneumatic systems to deliver solvent streams at controlled pressures (typically 10-100 bar) onto the adhesive layer. This high-pressure fluid delivery mechanism ensures complete and uniform solvent penetration through the adhesive layer, achieving rapid and thorough debonding of carrier-workpiece pairs with high productivity and consistency, while the controlled pressure prevents excessive force that could damage ultra-thin wafers
2Ease of manufacture
If conventional solvents are used for debonding, then the adhesive can be dissolved, but the cleaning process requires separate steps and costs more
Solution Approach 1:
The patent combines the debonding function and the cleaning function into a single integrated process step. The same high-pressure solvent stream that dissolves and removes the adhesive from the workpiece surface also simultaneously cleans any adhesive residue from the carrier surface. This dual-function approach eliminates the need for separate cleaning operations, simplifies the manufacturing process, and reduces overall solvent consumption while improving productivity
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
This method enhances process efficiency, reduces defects, and increases wafer throughput, allowing for a broader selection of polymeric adhesives and lower overall costs by combining debonding and cleaning into a single integrated step.
Implementation Method 1
The liquid solvent is capable of dissolving the adhesive
Implementation Method 2
The stream of the liquid solvent is applied at a pressure ranging from 60 to 10000 pounds per square inch (psi)
Data Source
AI summary
A method of debonding a temporarily adhesive-bonded carrier-workpiece pair employs a stream of a solvent at a high pressure. The carrier and the workpiece are bonded with an adhesive that is dissolvable in a selected solvent. The workpiece such as a device wafer may have been thinned and processed. The solvent is applied to the adhesive at a high pressure to debond and dissolve the adhesive with high throughput. The dissolved adhesive can be recycled and later reused, thus lowering the cost of the whole bonding and debonding process.