Production of diffraction grating

Abstract

Abstract PURPOSE:To produce a diffraction grating having a good shape without irregularity with satisfactory yield by using a photoresist having good resolution. CONSTITUTION:An AZ1350B.SF film 2 which is a novolak type photoresist is selectively formed on an InP semiconductor substrate 1 and a silicon nitride film 3 and an RV-1100N film 4 which is a novolak type negative photoresist are successively formed over the entire surface; thereafter, the photoresists are subjected to interference exposing by using two beams of He-Cd laser light. The RV-1100N film 4 is then developed and with the periodically formed RV-1100N film 4 as a mask, the silicon nitride film 3 is etched and further with the silicon nitride film 3 and the AZ1350B.SF film 2 as a mask, the InP semiconductor substrate 1 is etched to obtain the diffraction grating 5. After the RV-1100N film 4 is removed, the silicon nitride film 3 is removed and an NNR film 6 which is the negative type photoresist is formed only on the diffraction grating 5. The AZ1350B.SF film 2 is developed and with the NNR film 6 and the AZ1350B.SF film 2 as a mask, the InP semiconductor substrate 1 is etched to obtain the diffraction grating 7.

Inventors

• 👤 Takaaki Inoue
• 👤 貴陽 井上

Bibliographic Details