Patent ID: 7288366

Claim:
A method for forming a photoresist pattern on a prescribed film, said photoresist pattern having a multi-level profile formed from exposure to light transmitted through a reticle having a multi-level profile, the method comprising the steps of: a) providing a reticle; the reticle comprises one or more films overlying a reticle substrate to partially transmit and shift the phase of incident light, said reticle is comprised of the reticle substrate, a partially transmitting phase shift film, and an opaque film; the reticle substrate passing essentially all incident light, and the partially transmitting phase shift film transmitting approximately between 20% to 70% of incident light and shifting the phase about 180 degrees in transmission through the partially transmitting phase shift film, and the opaque film overlying sections of the partially transmitting phase shift film, the opaque film blocking light so that essentially all incident light is attenuated; b) exposing a light sensitive photoresist film, having a predetermined thickness, to light transmitted through the reticle for a predetermined amount of time, with light being transmitted through the reticle substrate exposing a first photoresist area of said light sensitive photoresist film to a first dosage, with light being transmitted through the partially transmitting phase shift film exposing a second photoresist area of said light sensitive photoresist film to a second intermediate dosage, and with light being transmitted through the opaque film exposing a third photoresist area of said light sensitive photoresist film to a third dosage; said light sensitive photoresist film is comprised of a lower photoresist layer and an upper photoresist layer; said lower photoresist layer is less or more sensitive to light than said upper photoresist layer; and c) developing the light sensitive photoresist film exposed in step (b) to form a photoresist profile having an opening in the first photoresist area, the photoresist profile having the predetermined thickness in the third photoresist area, and the photoresist profile having an intermediate thickness, between the predetermined thickness and zero, in the second photoresist area.