PSA film for semiconductor industry applications
A newly developed PSA maintains adhesion after thermal treatment but reduces adhesion after photo treatment, enabling easy removal from silicon wafers.
Acrylic pressure-sensitive adhesives (PSAs) often exhibit poor heat resistance. This poses challenges in high-temperature applications in semiconductor processing and enhancing the heat resistance of PSAs has been achieved through chemical crosslinking. Now, PSAs were developed that maintain adhesion during thermal treatment and reduce adhesion after photo treatment, allowing easy separation from silicon wafers.
Valuable insights
The PSA was synthesised by copolymerisation of 2-ethylhexyl acrylate (2-EHA), acrylonitrile (AN), and 4-hydroxybutyl acrylate (4-HBA) with final composition ratios of 72.6, 12.3, and 15.1 mol% respectively. Hexamethylene diisocyanate (HDI) and 2-isocyanatoethyl methacrylate (MOI) were attached to the hydroxyl group of 4-HBA to control the degree of crosslinking The peel strength of PSAs decreased from 9.64 N/in. to 6.75 N/in. after thermal treatment. This decrease is attributed to increased crosslinking density through AN cyclisation during the thermal treatment unlike conventional PSA which is inseparable after thermal treatment. After photo treatment, peel strength decreased from 6.75 N/in. to 3.62 N/in., indicating additional crosslinking due to intermolecular reactions of the methacrylate groups in MOI.
As the researchers point out, their results provide valuable insights for engineering PSAs with controlled adhesion characteristics, thereby enabling the development of advanced PSAs suited for semiconductor industry applications.
The study has been published in Progress in Organic Coatings, Volume 199, February 2025, 08950.
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