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

Abstract

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.