Non-Silicone Pressure-Sensitive Adhesive for Microelectronic Lapping
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Solution Overview
Problem
Silicone-based pressure-sensitive adhesives used in microelectronic device lapping processes tend to swell or leach, causing contamination and adhesion issues, particularly in hard disk drive systems, where even minimal silicone exposure can impair sensor performance and lead to errors or drive failure.
Innovation Solution
Employing non-silicone-based pressure-sensitive adhesives, such as polyacrylate or polyurethane materials, that exclude tin catalysts and are resistant to mineral oil, with specific mechanical and adhesive properties like elastic modulus, tan delta, peel force, and chemical stability to securely hold microelectronic device substrates during the lapping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silicone-based pressure-sensitive adhesives are used to secure substrates during lapping, then adhesion strength is improved, but contamination occurs causing adhesion issues and sensor impairment
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by specifying non-silicone-based polymers (polyacrylate, polymethacrylate, polyurethane) with specific molecular weight ranges and chemical structures. This parameter change eliminates silicone contamination while maintaining adhesion strength through carefully controlled polymer properties and functional groups.
Solution Approach 2:
The patent creates a composite adhesive formulation combining multiple non-silicone polymer types (polyacrylate, polymethacrylate, polyurethane) with specific ratios. This composite approach allows the adhesive to achieve both strong bonding to substrates and carriers during lapping while remaining chemically inert and non-contaminating to sensitive microelectronic components.
2Reliability
If adhesive materials are used to hold substrates during lapping, then substrate security is improved, but material swelling or leaching occurs causing contamination
Solution Approach 1:
The patent specifies precise parameter ranges for the adhesive polymers including molecular weight (10,000-1,000,000), functional group types, and chemical composition. These parameter controls ensure the adhesive maintains dimensional stability and chemical inertness during lapping, preventing swelling or leaching while securing substrates reliably.
Solution Approach 2:
The patent formulates the adhesive as a single-use, non-recoverable material that is discarded after the lapping process. This approach allows optimization for substrate security during the critical lapping window without concern for long-term durability, while the controlled composition ensures no residual contamination remains on substrates or carriers.
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
These adhesives effectively secure substrates without contamination, ensuring precise material removal and desired surface shaping, enhancing the performance and reliability of microelectronic devices by preventing silicone-related issues and maintaining adhesive integrity.
Implementation Method 1
an elastomeric pressure-sensitive adhesive to secure the microelectronic device substrate to a carrier that holds the substrate to a surface of the carrier during the lapping step
Implementation Method 2
a lapping step which is sometimes also referred to as an 'Actuated Kiss lap process' ('AKL') or a 'final polishing step,' wherein the step includes the use of an elastomeric pressure-sensitive adhesive to secure the microelectronic device substrate to a carrier
Data Source
AI summary
Described are methods for processing microelectronic device substrates by a lapping step, e.g., a final lapping step, wherein the step includes the use of an elastomeric pressure-sensitive adhesive to secure the microelectronic device substrate to a carrier that holds the substrate to a surface of the carrier during the lapping step, and wherein the pressure-sensitive adhesive can be a non-polysilicone based adhesive having mechanical properties that include a tan delta that is below about 0.2.