Patent ID: 7977213
Filing Date: 2011-07-12
Classification: B23K,H01L

Abstract:
1. A method of scribing semiconductor devices with minimal debris generation, comprising: providing a patterned semiconductor workpiece containing multiple, mutually spaced apart semiconductor devices that include multilayer structures fabricated on a semiconductor substrate and that are separated by dicing streets, the multilayer structures including mechanically weak upper and mechanically strong lower layers of material located depthwise, respectively, farther from and nearer to the semiconductor substrate, the mechanically weak upper layers including electrically conductive and low-k dielectric materials characterized by weak thermo-mechanical strength properties and the mechanically strong lower layers including dielectric material characterized by strong thermo-mechanical strength properties, and the mechanically strong lower layers including a layer of silicon oxide material functioning as a laser energy transparent stop layer for the mechanically weak upper layers; generating a pulsed laser beam of multiple temporally spaced apart laser pulses characterized by a wavelength, pulse width, and fluence such that the mechanically weak upper layers absorb the laser beam and the mechanically strong lower layers transmit the laser beam; aligning the pulsed laser beam with one of the dicing streets; and imparting relative motion between the pulsed laser beam and the semiconductor workpiece lengthwise along the dicing street to effect, with minimal debris generation, depthwise removal of the mechanically weak upper layers and thereby form a laser scribe region having side boundaries that are defined by exposed portions of the laser energy transparent stop layer and remain substantially undamaged by the pulsed laser beam.