During the year various characterisations on Scanning Electron Microscope (SEM) and micromanufacturing on femtosecond laser machine were done. The samples processed in the lab for micro manufacturing and characterization have a wide variety of material namely Copper, Tungsten, Ceramic Substrate, Alumina, photonic material composite deposited on a wafer , sapphire and Silicon. The requirements of micro manufacturing ranged in the dimension of the order of hundred microns with required tolerances less than 10 microns. The geometries covered mainly are line with spacing and circular geometry for making micro-holes. Several cutting through designs have also been explored. Manufacturing of high aspect ratio geometry, e.g. holes of the order of 100 microns in millimeter deep copper plate has been successfully demonstrated. Measurement and dimensional analysis on the laser manufactured micro featured samples using SEM have been conducted with bare minimum post processing i.e. ultrasonic bath and then with chemical post-processing to remove heat affected zones (HAZ). It has been found that HAZ remained negligible in comparison to other manufacturing techniques and surface finishes have also been analyzed by visual inspection which is also very good for the application requirements like Microwave components. For example average HAZ have been 4% in a circular cut on copper, and an average roundness of the circular cut is 19.37 micron for intended diameter of 130-micron, both are satisfactory. Similar measurements have been done on linear cut and right angle cut. The images (Fig. 1) show sample of work (a) circular cut (b) linear cut (c & d) on cleaning without chemical agent and with a chemical agent.
Fig. 1: (a) Circular cut (b) Linear cut (c ) Cleaning without chemical agent (d) Cleaning with a chemical agent