Method for manufacturing holographic bi-blazed grating

摘要

A method for manufacturing a holographic bi-blazed grating. Two blaze angles of the holographic bi-blazed grating are respectively a blaze angle A and a blaze angle B, and oblique-ion beam etching is performed on two grating areas A and B respectively by using a photoresist grating (12) and a homogeneous grating (14) as masks, thereby implementing different controls on the two blaze angles, and avoiding a secondary photoresist lithography process. Because when manufacturing the homogeneous grating (14), the time of positive ion beam etching can be controlled, so that the groove depth of the homogeneous grating (14) is controlled accurately. In addition, because the homogeneous grating mask and a substrate (10) are made of the same material, etching rates of the two are consistent, so that the accurate control of blaze angles can be implemented.

主权项

1. A method for fabricating a holographic bi-blazed grating, wherein: two blaze angles of the holographic bi-blazed grating are respectively a blaze angle A and a blaze B, and the bi-blazed grating is divided into two regions with a grating region A corresponding to the blaze angle A and a grating region B corresponding to the blaze angle B; the fabricating method comprises the following steps:
1) coating a photoresist layer on a substrate, wherein a thickness of the photoresist layer depends on the blaze angle A; 2) performing lithography on the photoresist layer to form a photoresist grating for fabricating the blaze angle A; 3) shielding the grating region B, performing tilted-Ar ion beam etching on the substrate by using the photoresist grating as a mask to etch different portions of the substrate in the grating region A with an obscuring effect of the photoresist grating mask on the ion beam, to form a blazed grating with the blaze angle A; 4) shielding the grating region A, and performing vertical ion beam etching on the substrate in the grating region B by using the photoresist grating as a mask, to form a homogeneous grating in the grating region B by transferring a pattern of the photoresist grating, wherein a depth of the etching depends on the blaze angle B; 5) cleaning the substrate to remove remaining photoresist; 6) shielding the grating region A, performing tilted-Ar ion beam scanning etching on the substrate by using the homogeneous grating as a mask to etch different portions of the substrate in the grating region B with an obscuring effect of the homogeneous grating on the ion beam, to form a blazed grating with the blaze angle B; and 7) cleaning the substrate to obtain the bi-blazed grating with the two blaze angles.