Patent ID: 7938975

Claim:
A process of forming at least one fluid supply slot in a substrate chip for use in a micro-fluid ejection head, the process comprising the steps of: (a) applying a photoresist planarization layer to a first surface of the chip, the planarization layer having a thickness ranging from about 1 to about 10 microns; (b) patterning and developing the photoresist planarization layer to define at least one fluid supply slot location therein and to define contact pad areas for electrical connection to a control device; (c) applying a photoresist etch mask layer to the photoresist planarization layer on the chip, the photoresist etch mask layer having a thickness ranging from about 10 to about 100 microns; (d) patterning and developing the photoresist etch mask layer with a first photomask to define the at least one fluid supply slot location in the photoresist etch mask layer; (e) inducing deprotection of the photoresist etch mask layer in a select second area of etch mask layer by exposing the select second area to radiation through a second photomask sufficient to deprotect the photoresist etch mask layer in the select second area so that the photoresist etch mask layer in the select second area can be substantially removed with a solvent without substantially affecting the photoresist planarization layer; (f) dry etching the chip to form at least one fluid supply slot in the defined at least one fluid supply slot location; and (g) removing the photoresist etch mask layer from the planarization layer.