Abstract
The fabrication of modern microelectronic silicon devices mechanically challenges these thin silicon substrates during manufacturing operations. Melt and solution polyesterification enabled the synthesis of polyesters containing photoreactive o-nitro benzyl ester units for use as a potential photocleavable adhesive. Melt transesterification provided a solvent-free method for synthesis of 2-nitro-p-xylylene glycol (NXG)-containing polyesters of controlled molecular weights. 1H NMR spectroscopy confirmed the chemical composition of the photoactive polyesters. Size exclusion chromatography (SEC) determined the number-average molecular weights (Mn) of the polyesters synthesized in the range of 6000 to 12000 g/mol. 1H NMR spectroscopy confirmed increasing levels of photocleavage of the o-nitro benzyl ester functionality with increasing exposure to broad wavelength UV irradiation, and exposure levels ranged from 0-187 J/cm2 UVA. Photocleaveage of approximately 90% of the o-nitro benzyl ester (ONB) units within the backbone of the polymer occurred at maximum dosage. Wedge fracture testing revealed approximately a two-fold decrease in fracture energy upon UV irradiation, suggesting that these structural adhesives offer potential for commercial "flip bonding" applications.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 548-558 |
| Number of pages | 11 |
| Journal | Journal of Adhesion |
| Volume | 89 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 3 2013 |
| Externally published | Yes |
Keywords
- Melt transesterification
- Micro-fabrication processes
- Photoreactive
- Polyester
- Reversible adhesives
- Structural adhesives
- Temporary bonding
ASJC Scopus subject areas
- Chemistry(all)
- Mechanics of Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry