Stretchability improvement of flexiable electronics by laser micro-drilling array holes in PDMS film

• Published in: Optics and lasers in engineering 2020-11, Vol.134, p.106307, Article 106307
• Main Authors: Rong, Youmin, Huang, Yu, Lin, Chaoran, Liu, Yifei, Shi, Songxin, Zhang, Guojun, Wu, Congyi
• Format: Article
• Language: English
• Subjects: 355 nm nanosecond laser; Flexible electronics; Laser micro-drilling; PDMS film
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/j.optlaseng.2020.106307

•Array micro-holes in PDMS film are manufactured by 355 nm nanosecond laser micro-drilling.•Heat-induced carbonization is an inner mechanism of PDMS laser micro-drilling.•Effect of drilling parameters on hole quality (diameter, roundness, and HAZ) is analyzed.•Tensile limit of flexible electrode is improved from 16 % to 38 %. The preparation of micro-holes through flexible substrate is an effective method for improving stretchability of flexible electronics. Quantitative fabrication of micro-holes on polydimethylsiloxane (PDMS) film was achieved by using the 355 nm nanosecond laser. An Orthogonal experiment with 3-factors and 5-levels was designed to discuss the influence of processing parameters (pulse repetition frequency, drilling speed, and drilling times) on the quality of micro-holes from the view of diameter, roundness, and heat-affected zone (HAZ). It was found that heat-induced carbonization is an inner mechanism during the nanosecond laser micro-drilling process of PDMS. The optimal combination of processing parameters was obtained, the pulse repetition frequency was 180 kHz, the drilling speed was 0.015 mm/min, and the drilling times was 75. While the smallest micro-hole diameter (29.6 ± 3.4 μm) and HAZ (8.4 ± 2.7 μm) were obtained, the best micro-hole roundness (1.7 ± 0.6 μm) was achieved. The tensile limit of flexible electrode prepared with the array micro-hole PDMS (diameter 29.6 ± 3.4 μm, center distance 60 μm) was increased from 16% to 38%, compared with that being prepared with the planar PDMS.