Method of optical proximity correction
AssigneeMacronix International Co., Ltd.
InventorShun-Li Lin
Life of this patent
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Abstract
A method of optical proximity correction, suitably applied to a photolithography process with a high numeric aperture. The exposure light comprises a P-polarized light and an S-polarized light perpendicular to the P-polarized light. The P-polarized light has a transmission coefficient larger than that of the S-polarized light. In this method, different optical proximity correction modes are applied to the patterns with different orientations. While correcting any pattern, the ratio of transmission coefficient of the P-polarized light to the S-polarized light and the polarization angle between the pattern orientation and the polarization direction of the P-polarization/S-polarization light are considered.
Claims21
A method of optical proximity correction, applicable to a photolithography process that employs a light source having P-polarized light and S-polarized light and a photomask comprising a plurality of patterns, wherein the P-polarized light has a transmission coefficient larger than that of the S-polarized light, and two patterns with different orientations are selected, the method comprising:
- using different optical proximity correction models to correct each pattern according to a ratio of the transmission coefficient between the P- and S-polarized lights, the orientations of each pattern, and an angle between polarization directions of the P- and S-polarized lights so that said plurality of patterns can be transferred onto a photoresist layer by performing a single exposure step.
A photolithography process, comprising:
- providing a substrate;
- forming a photoresist layer on the substrate;
- providing an exposure light source with a S-polarized light and a P-polarized light with a transmission coefficient larger than that of the S-polarized light;
- and
- providing a photomask with a plurality of patterns, wherein any two of the patterns have different orientation, and each pattern has been corrected with different optical proximity correction model considering a ratio of transmission coefficient between the P- and S-polarized lights, the orientation of each pattern and an angle between the polarization directions of the P- and S-polarized directions, so that said plurality of patterns can be transferred onto the photoresist layer by performing a single exposure step using the exposure light source.
A method of optical proximity correction, applicable to a photolithography process that employs a light source having P-polarized light and S-polarized light and a photomask comprising at least a first pattern having a first pitch along a first direction and a second pattern having a second pitch along a second direction, wherein said first pitch is same as said second pitch, and wherein the P-polarized light has a transmission coefficient larger than that of the S-polarized light, the method comprising:
- using different optical proximity correction models to enlarge said second pitch such that said second pitch is larger than said first pitch so that a total intensity profile of said second pattern can be widened.
Dependencies are inferred from the claim text.