Method and apparatus for generating periodic patterns by step-and-align interference lithography
The present invention provides a method and an apparatus for generating periodic patterns by step-and-align interference lithography, wherein at least two coherent light beams with a pattern are controlled to project onto a substrate to be exposed to form an interference-patterned region on the substrate. Thereafter, by means of moving the substrate or the light beams stepwisely, a patterned region with a large area can be formed on the substrate. According to the present invention, the optical path and exposure time may be shortened to reduce defect formation during lithographic processing and to improve the yield.
1. An apparatus for generating periodic patterns by step-and-align interference lithography, comprising:
a light generating unit, capable of generating at least two coherent light beams with a pattern;
a carrier unit, capable of carrying a substrate to be exposed to the at least two coherent light beams simultaneously to form a patterned interference region on the substrate at one of plural exposure shot areas; and
a driver unit, coupled to the carrier unit to provide a driving force to move the carrier unit stepwisely so that another patterned interference region is formed by alternating motions of one stepwise movement of the carrier unit and one shot of exposure of the at least two coherent light beams simultaneously incident on the substrate, wherein the substrate is prevented from being exposed to the coherent light beams when the carrier unit is moving,
wherein the patterned interference regions are configured so that the exposure patterns of the patterned interference regions are identical to each other, and
wherein a right boundary of each patterned interference region is identical to a left boundary of a corresponding neighboring patterned interference region, or an upper boundary of each patterned interference region is identical to a lower boundary of a corresponding neighboring patterned interference region.
2. The apparatus as recited in claim 1 , wherein the light generating unit further comprises:
a beam generator, capable of generating at least a light beam;
a beam shaper, capable of receiving and shaping the light beam to form a shaped light beam with uniform intensity; and
a beam splitter, capable of splitting the shaped light beam into the at least two coherent light beams.
3. The apparatus as recited in claim 1 , wherein the pattern is polygonal or arc-sided.
4. The apparatus as recited in claim 1 , wherein the substrate is planar or arc-surfaced.
5. The apparatus as recited in claim 4 , wherein the substrate is cylindrical.
6. The apparatus as recited in claim 1 , wherein the light generating unit further comprises an adjustment device for adjusting an incident angle of the coherent light beams onto the substrate.
7. The apparatus as recited in claim 1 , wherein the carrier unit is capable of rotating.
8. The apparatus as recited in claim 1 , wherein the coherent light beams have a uniform light intensity.
9. The apparatus as recited in claim 1 , wherein the substrate is one of a semiconductor substrate, a glass substrate, a plastic substrate, a metal substrate, a flexible substrate and a rubber substrate.
10. The apparatus as recited in claim 1 , wherein each of the patterned interference region shares at least one boundary thereof with the neighboring patterned interference region.