Reticle design for alternating phase shift mask
AssigneeMicron Technology, Inc.
InventorsWilliam A. Stanton, Vishnu K. Agarwal
Life of this patent
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Abstract
The present invention provides a method and apparatus for producing 0 degree light and 180 degree phase shifted light having substantially equal intensities as both lights exit an alternating phase shift reticle. A material is inserted within the etched portion of the 180 degree phase shift channel of a reticle, wherein the material contains an index of refraction such that the first order light (+1, −1) is propagated through the 180 degree channel. The end result is a 180 degree phase shifted light having an intensity substantially equal to that of the 0 degree light.
Claims19
A method of using an alternating phase shift reticle, said method comprising:
- generating light from a light source;
- receiving first light rays from said light source and transmitting them through a 0 degree optical channel of said reticle, whereupon they exit with a first light intensity;
- receiving second light rays from said light source and transmitting them through a 180 degree phase shifted optical channel of said reticle;
- and
- transmitting said second light rays through a material which causes an intensity of light exiting said 180 degree phase shifted optical channel to be approximately equal to said first light intensity, said material being separate from said 0 degree and said 180 degree phase shifted optical channels.
A method of patterning photoresist, the method comprising:
- shining light from a light source onto an alternating phase shift reticle located between said photoresist and said light source;
- and
- creating a predetermined pattern on said photoresist, said alternating phase shift reticle further comprising:
- a substrate having a 0 degree light path and an etched 180 degree phase shifted light path therein;
- and
- a material provided in at least one of said 0 degree and said etched 180 degree paths which causes an intensity of light exiting said etched 180 degree light path to be approximately equal to an intensity of light exiting said 0 degree light path, said material being separate from said 0 degree and said etched 180 degree light paths.
A method of transmitting light through an alternating phase shift reticle, said method comprising:
- receiving light rays from a light source and transmitting them through a 0 degree optical channel of said reticle;
- receiving light rays from said light source and transmitting them through a 180 degree phase shifted optical channel of said reticle;
- passing first order light of said light rays through said 0 degree optical channel;
- passing first order light of said light rays through said 180 degree phase shifted optical channel;
- and
- passing said first order light of said light rays passing through said 180 degree phase shifted optical channel through a material which causes an intensity of light exiting said 180 degree phase shifted optical channel to be approximately equal to an intensity of light exiting said 0 degree optical channel, said material being separate from said 0 degree and said 180 degree phase shifted optical channels.
Dependencies are inferred from the claim text.