Analysis of a phase-modulating recording mechanism in negative photoresist

Abstract

We describe a process that produces an index-of-refraction modulation requiring no wet development. A negative photoresist, which is currently employed as a surface-modulating material in high-resolution photolithography, was used. This process may be useful in real-time optical recording. It could eventually be shown to be responsible for defects in high-resolution photolithography.

Holographic technique for measurement of the kinetic constant and optical modulation of photosensitive materials

“…As can be seen from Eqs. (10) and (11), if there is no external phase perturbations ðψ ¼ 0 ⇒ sin ψ ¼ 0; cos ψ ¼ 1Þ, the amplitude of the first harmonic is proportional to the efficiency of the phase grating, whereas the amplitude of the second harmonic is proportional to the efficiency of the amplitude grating [20]. Thus by using two lock-in amplifier switches at the first and second harmonics, respectively, the signal from both gratings can be measured simultaneously and separately.…”

“…(10)] can be neglected and the amplitude of the first harmonic signal [Eq. (10)] can be measured with a lock-in amplifier and used as system feedback until it reaches equilibrium when the feedback signal vanishes. In this situation, cos ψ ¼ 0 in Eq.…”

“…In this situation, cos ψ ¼ 0 in Eq. (10), which corresponds to either a bright or a dark fringe [ Fig. 3(b)] at the detector [from Eq.…”

“…If we assume that ψ ¼ 0 (because of the fringe locker system), voltage signals V Ω and V 2Ω , measured with the lock-in amplifiers that are connected to the photodetector, are, respectively, proportional to the irradiance harmonics described by Eqs. (10) and (11):…”

“…In this case a periodic modulation of the optical constants will be recorded in the photosensitivity material that can be measured by diffraction [9]. This method allies the high sensitivity of the diffraction measurements [10] with the possibility to measure the spatial resolution [11].…”