Scribe street width reduction by deep trench and shallow saw cut

Abstract

In a method to singulate a semiconductor wafer (100) into chips, trench streets (107) of predetermined depth (105a) are formed across the first, active wafer surface (102) to define the outline of the chips (101). Thereafter, the fabrication of the active first wafer surface is completed and protected. Then, the wafer is flipped to expose the second wafer surface (103), and the wafer is subjected to a cutting saw. The saw is aligned with the trenches in the first surface so that the saw cuts the second surface along streets (106), which extend the trenches through the wafer. The saw is stopped cutting at a depth (105b), when the saw streets just coalesce with the trench streets, respectively, whereby the chips are completely singulated.

Description

FIELD OF THE INVENTION [0001] The present invention is related in general to the field of semiconductor devices and more specifically to a method of dicing semiconductor wafers. DESCRIPTION OF THE RELATED ART [0002] With most semiconductor products, for example integrated circuits, transistors and diodes, a large number of elements are manufactured simultaneously on a large semiconductor wafer of silicon, gallium arsenide, gallium phosphide etc. The semiconductor industry employs the terms “singulation”, “dicing technologies” or “scribing technologies” to refer to those techniques for obtaining a large number of functional chips from each semiconductor wafer. Two dicing methods are particularly well known in the art: the grinding-cutting method, using a blade or wire saw, and the scribing method, using a diamond point. Modern silicon technology prefers the cutting method using high-speed rotating blades. For reasons of mechanical stability at high rotating speeds, the blades have to...

AI Technical Summary

Benefits of technology

"The invention is a method to make semiconductor chips by cutting a wafer into individual chips. The method involves creating shallow trenches on the surface of the wafer and then using a cutting saw to cut the wafer along the trenches. This results in chips that are separated from each other, with no damage to the active areas of the chip. The method is cost-effective and easy to implement in semiconductor manufacturing, as it uses existing equipment and techniques. The technical effects of the invention include improved efficiency in chip production and better reliability of the chips."

Problems solved by technology

For reasons of mechanical stability at high rotating speeds, the blades have to possess a particular thickness, which cannot safely be reduced.

In particular the third of these restrictions, namely the generation of cracks, creates the most significant limitation with respect to decreasing the distance between adjacent circuit chips.

In addition, those cracks represent significant reliability risks, since they tend to grow and widen under thermal and mechanical stress and thus eventually imperil the functionality of the integrated circuit.

Images