Use of a U-groove as an alternative to using a V-groove for protecting silicon against dicing induced damage
AssigneeXerox Corporation
InventorsAlain E. Perregaux, Paul A. Hosier, Josef E. Jedlicka, Nicholas J. Salatino, Jagdish C. Tandon
Life of this patent
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Abstract
The present disclosure relates that by modifying chip die dicing methodology to a U-groove profile from a V-groove profile by modifying the second etch step to be a dry etch instead of a wet etch results in a direct cost savings by eliminating a more expensive process step, as well as the need for stripping the developed photoresist layer. Furthermore, going to a U-groove profile accomplishes additional indirect and greater cost savings resulting from increased process throughput, improved yield, and reduced metal layer defects.
Claims26
A method for dicing die from a semiconductor wafer while allowing a very close cut of a die edge relative to active elements on the die without damaging the active elements comprising:
- etching a U-groove via a dry etch in the semiconductor wafer;
- and
- sawing the semiconductor wafer along the U-groove where one edge of the saw is substantially in alignment with the bottom of the U-groove.
A method for dicing die from a semiconductor wafer while allowing a very close cut of a die edge relative to active elements on the die without damaging the active elements comprising:
- etching by way of a first dry etch an opening down to the surface of the semiconductor wafer;
- etching by way of a second dry etch a U-groove in the opening down to the surface of the semiconductor wafer created by the first dry etch;
- and
- sawing the semiconductor wafer along the U-groove where one edge of the saw is substantially in alignment with the bottom of the U-groove.
A method of fabricating high resolution image sensor dies from a wafer so that the dies have precision faces to enable the dies to be assembled with other like dies to form a larger array without image loss or distortion at the points where the dies are assembled together, comprising the steps of:
- etching small U-shaped grooves in one side of a wafer delineating the faces of the dies where the dies are to be separated from the wafer;
- forming grooves in the opposite side of the wafer opposite each of the U-shaped grooves, the axis of the grooves being parallel to the axis of the U-shaped groove opposite thereto;
- and
- sawing the wafer along the U-shaped grooves with one side of the cut made by sawing being substantially coextensive with the bottom of the U-shaped grooves whereby one side of the U-shaped grooves is at least partially obliterated by the sawing, the sides of the U-shaped grooves that remain serving to prevent development of fractures in the die beyond the remaining side as the wafer is being sawed.
Dependencies are inferred from the claim text.