ULTRAFAST LASERS AND ITS USE IN ELECTRONICS INDUSTRY

Abstract

The size of semiconductors and packaged devices continues to shrink enabling the devices to become more compact . This trend requires the deployment of sophisticated equipments with inbuilt lasers that have unique capability to process diverse materials with high precision , but without damaging the electronic components due to heat . There are diverse laser technologies utilising longer pulse width or ultrashort pulse (USP) width that are employed in electronic packaging applications . USP lasers are also known as ultrafast lasers .The primary benefit of USP lasers over longer pulsewidth lasers is that it produces minimal heat affected zone during processing . Thus USP lasers are ideal for encasing delicate materials or precision shaping of electronic devices and also for ceramic welding. Ceramics are heat-resisting materials which can withstand temperatures upto 1200 0C , but at the same time can retain mechanical strength . They are also biocompatible , hard and can not be shattered easily . These properties make ceramics a great material for packaging biomedical implants , semiconductors , sensors , ICs etc . In defence sector , space application and to operate furnaces , electronic devices that can withstand very harsh environment are required . Encapsulation of electronic components with refractory material is the right solution . But sealing of the electonic components inside ceramics is not easy , because the entire system would have to be put in a furnace , which would end up the components to burn to ashes . Recently researchers have developed a new ceramic welding technique at ambient temperature using an ultrafast pulsed laser with rated power of about 50 watts . As the name implies the lasing device sends a short burst of laser pulses to the material interface causing localised melting at the interface of the two halves of the ceramic casing and are welded together without any damage to the semiconductors . To make the system workable researchers have to fine tune the length of pulses , exposure time , number of pulses and also the transparency of the ceramic has to be considered .