Patent ID: 6586702
Filing Date: 2003-07-01
Classification: B23K,H01L

Abstract:
A method for micro-milling a substrate to a predetermined depth, comprising the steps of:directing a laser beam at a predetermined intensity towards a first surface of a substrate of a piezoelectric material to be micro-milled; moving the substrate material relative to the laser beam at a predetermined constant velocity along a predetermined path so as to ablate a series of grooves in the surface of a substrate material by application of a predetermined uniform flux per unit area; and the relative movement of the substrate material and laser beam along each line in said set of lines being repeated until the material has been ablated sufficiently to form a groove of a predetermined depth; whereby grooves are ablated in a predetermined grid pattern to form a series of pixels with kerfs or grooves separating the pixels, each pixel having a first end at said first surface and a second end; and covering the first ends of the pixels with a layer of acoustic matching material extending over the pixels, whereby the resultant pixel array can transmit and received ultrasonic waves.