A method of forming a scribe line having a sharp snap line entails
directing a UV laser beam along a ceramic or ceramic-like substrate such
that a portion of the thickness of the substrate is removed. The UV laser
beam forms a scribe line in the substrate without appreciable substrate
melting so that a clearly defined snap line forms a region of high stress
concentration extending into the thickness of the substrate.
Consequently, multiple depthwise cracks propagate into the thickness of
the substrate in the region of high stress concentration in response to a
breakage force applied to either side of the scribe line to effect clean
fracture of the substrate into separate circuit components. The formation
of this region facilitates higher precision fracture of the substrate
while maintaining the integrity of the interior structure of each
component during and after application of the breakage force.