Patterning of Aluminium thin film on polyethylene terephthalate by multi-beam picosecond laser. (November 2015)

• Record Type: Journal Article
• Authors: Jin, Y.; Perrie, W.; Harris, P.; Allegre, O.J.; Abrams, K.J.; Dearden, G.
• Is Part Of: Optics and lasers in engineering. Volume 74(2015)
• Page Start: 67
• Page End: 74
• Publication Date: 2015-11
• Subjects: Picosecond laser -- Spatial light modulator -- Ablation -- Computer Generated Hologram -- Thin film patterning; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2015.04.006
• Languages: English
• ISSNs: 0143-8166

Abstract

Abstract: High speed patterning of a 30 nm thick Aluminium thin film on a flexible Polyethylene Terephthalate substrate was demonstrated with the aid of Computer Generated Holograms (CGH׳s) applied to a phase only Spatial Light Modulator. Low fluence picosecond laser pulses minimise thermal damage to the sensitive substrate and thus clean, single and multi-beam, front side thin film removal is achieved with good edge quality. Interestingly, rear side ablation shows significant Al film delamination. Measured front and rear side ablation thresholds were F th =0.20±0.01 J cm −2 and F th =0.15±0.01 J cm −2 respectively. With laser repetition rate of 200 kHz and 8 diffractive spots, a film removal rate of R >0.5 cm 2 s −1 was demonstrated during patterning with a fixed CGH and 5 W average laser power. The effective laser repetition rate was f eff ~1.3 MHz. The application of 30 stored CGH׳s switching up to 10 Hz was also synchronised with motion control, allowing dynamic large area multi-beam patterning which however, slows micro-fabrication. Highlights: Picosecond laser patterning of thin film Aluminium on flexible PET. Front and rear side ablation single pulse thresholds determined. Parallel beam patterning with spatial light modulator at rate ~0.5 cm 2 s −1 . Dynamic patterning with 30 synchronised CGH׳s run in real time.