Optimization of the Ablative Laser Cutting of Shadow Mask for Organic FET Electrode Fabrication

Mariusz Tomczyk,Witold Waliszewski,Paweł Kubik

doi:10.3390/electronics9122184

Mariusz Tomczyk, Witold Waliszewski + Show 1 more

Open Access

https://doi.org/10.3390/electronics9122184

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Journal: Electronics	Publication Date: Dec 18, 2020
Citations: 5	License type: CC BY 4.0

Affiliation: Lodz University of Technology

Abstract

This article presents an ablative method of cutting masks from ultra-thin metal foils using nanosecond laser pulses. As a source of laser radiation, a pulsed fiber laser with a wavelength of 1062 nm with the duration of pulses from 15 to 220 nanoseconds (ns), was used in the research. The masks were made of stainless-steel foil with thicknesses of 30 µm, 35 µm, and 120 µm. Channels of different lengths from 50 to 300 µm were tested. The possibilities and limitations of the presented method are described. The optimization of the cutting process parameters was performed using the experiment planning techniques. A static, determined complete two-level plan (SP/DC 24) was used. On the basis of the analysis of the test structures, we designed and produced precise shading masks used in the process of organic field effect transistor (OFET) electrode evaporation. The ablative method proved suitable to produce masks with canals of minimum lengths of 70 µm. It offers facile, fast, and economically viable shadow mask fabrication for organic electronics applications, which moreover might enable fast prototyping and circuit design.

Highlights

Laser technologies are widely used in many industries
We demonstrate the effectiveness of the ablative effect of ns pulses to cut out ultra-thin masks
The created masks have already found application in the production of textronics as well as the electronics elements and systems [11]. One such example is shadow masks used to fabricate electrodes in vapor deposition process of metals. Electrodes prepared by this method are the most mainstream in organic field effect transistors (OFETs) and other organic electronic devices [12,13]

Summary

Introduction

Laser technologies are widely used in many industries. For many years, lasers have been successfully used to cut materials such as metals, semiconductors, plastics, and ceramics [1]. The created masks have already found application in the production of textronics as well as the electronics elements and systems [11] One such example is shadow masks used to fabricate electrodes in vapor deposition process of metals. One of the promising applications of OFETs are the flexible devices, which can be fabricated by alternating deposition of thin layers of OSC, metal electrodes, and polymer insulator (Figure 1) [17,18]. One of the electrode deposition methods used organic is vacuum obtain well-defined dimensions of the transistor channel. Electrodes obtained in the metal from vapor phase onto the sample in “high” vacuum through the so-called shadow vacuum deposition process ideally reflect the dimensions and shape of the shadow mask (in negative). With those used far due to the ease of adjusting the process parameters, time, and process ecology

Laser Process

3.3.Results

Discussion