Patent ID: 11914304
Assignee: TOYOTA MOTOR ENGINEERING & MANUFACTURING NORTH AMERICA, INC.
Field: Optics (Instruments)
Classification: CPC G  C | IPC C  G

Claim 12:
13. A method for controlling a density distribution of a three-dimensional photonic crystal template, comprising:
depositing a photoresist composition comprising a photoinitiator homogeneously distributed throughout a volume of the photoresist composition on a silicon substrate;
depositing a plurality of light reflective and/or light absorbing particles on the photoresist composition resulting in at least two areas above the silicon substrate having different amounts of the plurality of light reflective and/or light absorbing particles before irradiating,
irradiating the photoresist composition with at least four laser beams using a multibeam interference lithograph system to generate a periodic interference pattern comprising a periodic pattern of a gradient constructive volume and a destructive volume in an exposed photoresist composition, where an exposure duration is less than 0.3 seconds, and where the photoinitiator is at a concentration greater than a maximum amount that photolyzes in two seconds;
baking the exposed photoresist composition at a fixed temperature and time independent of the exposure duration to form a gradient-like periodic structure comprising a polymerized and gelled photoresist derived from the gradient constructive volume and an un-gelled photoresist in the destructive volume;
dissolving the un-gelled photoresist with a solvent to form an un-gelled photoresist solution; and
washing the un-gelled photoresist solution with a washing solvent from the three-dimensional photonic crystal template such that the three-dimensional photonic crystal template has a density gradient that is proportional to the exposure duration and a density of the three-dimensional photonic crystal template under the at least two areas with the plurality of light reflective and/or light absorbing particles is less than at least one area absent the plurality of light reflective and/or light absorbing particles.