US 6,185,830 B1 · Semiconductor wafer fixture for alignment in a grating exposure process

Abstract

A fixture and method for providing accurate and repeatable alignment and attachment of a semiconductor wafer to a corner cube exposure fixture includes a vacuum-assisted wafer holder of rectangular shape. The wafer holder is first placed upon an L-shaped loading fixture so that a wafer may be positioned against the front surface of the holder and manipulated until the pair of wafer flats abut each leg of the L-shaped fixture. When so aligned, a vacuum is applied to secure the attachment and alignment of the wafer vis-à-vis the wafer holder. The wafer holder is thereafter inserted in a corner cube exposure fixture, where the fixture is formed to include a right-angle bracket with alignment features formed in one leg of the angle. The wafer holder also includes alignment features in its bottom surface, where these features are formed to mate with the bracket upon attachment. The proper placement and alignment of the wafer holder to the exposure fixture results in the wafer being disposed immediately adjacent to the reflective surface used to form the interference pattern on the wafer surface. The right angle in the fixture ensures that the mirror surface remains orthogonal to the wafer surface such that a uniform grating may be formed across the wafer surface.

Claims14

Dependent claims

An arrangement for mounting and aligning a semiconductor wafer with a corner cube exposure fixture, the corner cube exposure fixture including a mirror surface for use in forming holographic grating patterns on a semiconductor wafer surface, the arrangement comprising

a rectangular wafer holder including a vacuum aperture through a front surface thereof for securing a semiconductor wafer thereto, said holder further comprising a plurality of alignment features formed in a bottom surface and a side surface thereof, said vacuum aperture disposed such that upon attachment of a wafer to said wafer holder, the wafer flats will be adjacent to a top surface and said side surface of said wafer holder;
and
an L-shaped loading fixture defined as including a lower surface and a perpendicular side surface, said loading fixture having suitable dimensions with respect to said rectangular wafer holder such that said wafer holder side surface rests against said loading fixture lower surface and said wafer holder top surface rests against said loading fixture side surface, wherein upon placement of a wafer against said wafer holder top surface, a first flat surface of said wafer abuts said loading fixture lower surface and a second flat surface of said wafer abuts said loading fixture side surface.

A method of aligning a semiconductor to a corner cube exposure fixture for use in a holographic grating exposure process, the method comprising the steps of:

a) providing a rectangular wafer holder including a vacuum aperture through a front surface thereof, said holder further comprising a plurality of alignment features formed in a bottom surface and a side surface thereof;
b) providing an L-shaped loading fixture defined as including a lower surface and a perpendicular side surface;
c) placing the rectangular wafer holder in relationship with said L-shaped loading fixture such that the wafer holder side surface is contiguous with the loading fixture lower surface and a top surface of the wafer holder is contiguous with the load fixture perpendicular side surface;
d) positioning a semiconductor wafer over the wafer holder front surface so as to cover the vacuum aperture, said semiconductor wafer including a major flat and a minor flat, the major and minor flats formed to be orthogonal to one another;
e) adjusting the position of said semiconductor wafer until the major flat is contiguous with the loading fixture lower surface and the minor flat is contiguous with the loading fixture perpendicular side surface;
and
f) applying a vacuum to said wafer holder to maintain the semiconductor wafer in the aligned position achieved in step e).

4 more elements

Dependencies are inferred from the claim text.

Semiconductor wafer fixture for alignment in a grating exposure process

Life of this patent

Semiconductor wafer fixture for alignment in a grating exposure process

Life of this patent

Abstract

Claims14