US 5,413,884 A · Grating fabrication using electron beam lithography

Abstract

A technique is disclosed for utilizing direct-write electron-beam photolithography and holographic optical exposure to form gratings in optoelectronic structures. The direct-write e-beam process is used to form rectangular grating teeth in a mask substrate, where the mask is then used as a phase mask to transfer the pattern to the optoelectronic device. Advantageously, the utilization of a direct write e-beam technique to form the grating pattern on the photomask allows for the formation of any desired number and location of abrupt phase shifts, multiple grating pitches, alignment fiducials, and any other desired features. Therefore, a single exposure of the direct write e-beam mask allows for a plurality of different grating patterns to be simultaneously printed.

Claims26

Dependent claims

A method of fabricating predetermined grating structures in optoelectronic devices, the method comprising the steps of:

a) providing a photomask including a grating pattern of rectangular grating features formed by a direct-write electron-beam lithography process, said grating pattern comprising any desired number and location of abrupt phase shifts and plurality of grating pitches;
b) illuminating said photomask with light at a predetermined angle .theta..sub.i sufficient to form a transmitted beam and a first-order diffracted beam;
c) exposing a photoresist-covered optoelectronic device substrate, such that the transmitted beam and first-order diffracted beam interfere to form a near-field intensity pattern in said photoresist which replicates said grating pattern;
and
d) developing said photoresist and transferring said grating pattern to the underlying optoelectronic device substrate.

2 more elements

Dependencies are inferred from the claim text.

Grating fabrication using electron beam lithography

Life of this patent

Grating fabrication using electron beam lithography

Life of this patent

Abstract

Claims26