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 Fth¼0.2070.01 J cm2 and Fth¼0.1570.01 J cm2 respectively. With laser repetition rate of 200 kHz and 8 diffractive spots, a film removal rate of R40.5 cm2 s1 was demonstrated during patterning with a fixed CGH and 5 W average laser power. The effective laser repetition rate was feff1.3 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.
Original language | English |
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Pages (from-to) | 67-74 |
Number of pages | 7 |
Journal | Optics and Lasers in Engineering |
Volume | 74 |
DOIs | |
Publication status | Published - Apr 2015 |
Keywords
- Picosecond laser