Effect of Au-Coating on the Laser Spot Cutting on Spring Contact Probe (SCP) for Semi-Conductor Inspection.

Youngjin Seo,Martin Byung Guk Jun,Jungsoo Nam,Huitaek Yun,Dongkyoung Lee

doi:10.3390/ma14123300

Abstract

Spring contact probes (SCPs) are used to make contact with various test points on printed circuit boards (PCBs), wire harnesses, and connectors. Moreover, they can consist of the test interface between the PCBs and the semiconductor devices. For mass production of SCPs, ultra-small precision components have been manufactured by conventional cutting methods. However, these cutting methods adversely affect the performance of components due to tool wear and extreme shear stress at the contact point. To solve this problem, laser spot cutting is applied to Au-coated SCP specimens as an alternative technique. A 20 W nano-second pulsed Ytterbium fiber laser is used, and the experimental variables are different laser parameters including the pulse duration and repetition rate. After the spot cutting experiments, the heat-affected zone (HAZ) and material removal zone (MRZ) formed by different total irradiated energy (Etotal) was observed by using a scanning electron microscope (SEM). Then, the size of HAZ, top and bottom parts of MRZ, and roundness were measured. Furthermore, the change rate of HAZ and MRZ on Au-coated and non-coated specimens was analyzed with regard to different pulse durations. Based on these results, the effect of Au-coating on the SCP was evaluated through the comparison with the non-coated specimen. Consequently, in the Au-coated specimen, hole penetration was observed at a low pulse duration and low total energy due to the higher thermal conductivity of Au. From this study, the applicability of laser spot cutting to Au-coated SCP is investigated.

Highlights

Various mechanical cutting methods have been widely used to fabricate ultra-small precision components of the electronic device for mass production
Higher pulse duration (100, 200 ns). These results show that the Au-coated zone spreads energy quicker, which results in Thebigger resultholes shows variation at azone highatpulse duration
The results were compared with a noncoated specimen to observe the Au-coating effect

Summary

Introduction

Various mechanical cutting methods have been widely used to fabricate ultra-small precision components of the electronic device for mass production. There are several major limitations of mechanical cutting methods which can cause the failure of components due to the extreme shear stress at the contact point and the tool wear. To overcome these problems, the laser cutting method has been studied because it has many advantages that provide non-contact, flexibility, high-intensity energy, rapid manufacturing, and various applications [1,2,3,4]. The laser cutting of electrodes for lithium-ion batteries has been conducted. Lutey et al found the main factors affecting laser cutting efficiency and the quality of lithium-ion batteries [9,10]. Laser cutting technology is applied to the carbon fiber reinforced plastic (CFRP) [12,13,14,15,16] and steel [17,18,19,20]

Methods

Results

Conclusion