US 8,193,259 B2, with title of “UV-CURABLE PRESSURE-SENSITIVE ADHESIVE COMPOSITION WITH A FLUORINATED ACRYLIC BINDER RESINAND PRESSURE-SENSITIVE ADHESIVE FILM USING THE SAME”, teaches a way to formulate UV Release (UVR) adhesive formulation where a fluorinated acrylic segment is introduced to the main chain to deliver excellent pick-up performances after UV illumination.
The formulation includes an acrylic binder, thermal cross-linker, and photo-initiator. The binder has several different segments including:
- A: F-containing acrylate segment: 6-30mol%. If it is less than 6%, the adhesion reduction performances is limited. If above 30%, the polymerization reaction is difficult and the initial bonding to wafer may be too low.
- B: Segment with -C=C and -NCO group: 10-25mol%
- C: Segment with hydroxyl group: 15 parts to about 30 parts by Weight (before reaction with -NCO to connect the cross linkable B)
- D: Segment with epoxy group: 2-10mol%. If the content is less than 2%, the adhesion to wafer/ring frame might be too weak, causing vibration of wafer during dicing process, which in turn leads to chip flying and ring frame delamination. Acid value should be less than 1. Otherwise the binder may gel, leading to physical properties changing with time.
Examples of Fluoro acrylates are trifluoromethylmethacrylate, trifluoroethylmethacrylate, hexafluoropropylmethacrylate, heptadecafluorodecyl acrylate, and so forth.