Patent ID: 6902867

Claim:
A method for making one or more ink feed vias in a semiconductor silicon substrate chip for an ink jet printhead, the chip having a thickness ranging from about 300 to about 800 microns and having a device surface side and an ink surface side opposite the device surface side, comprising the steps of: applying a layer of a first photoresist material having a first thickness to the device surface side of the chip; patterning and developing the first photoresist material to provide at least one ink via location therein and to planarize the device surface side of the chip; applying a layer of a second photoresist material having a second thickness to the ink surface side of the chip to provide a masking layer of photoresist material on the ink surface side of the chip; patterning and developing the second photoresist material to define the at least one ink via location in the second photoresist material on the ink surface side of the chip; applying a layer of a third photoresist material to the first photoresist material and device surface side of the chip; patterning and developing the third photoresist material to provide the at least one ink via location therein on the device surface side of the chip; anisotropically etching a first trench from the device surface side of the chip to a first depth and a first width using a first dry etch technique, the first trench being etched in the ink via location; applying an etch stop material in first trench and to first photoresist material or to the first and third photoresist material on the device surface side of the chip to provide an etch stop layer; anisotropically etching a second trench from the ink surface side of the chip up to the etch stop layer using a second dry etch technique, the second trench having a second width and being etched in substantially the same ink via location provided in the second photoresist material on the ink surface side of the chip; and removing the second photoresist material from the ink surface side of the chip; and removing the etch stop material from the device surface side of the chip to provide a chip having at least one ink via therein.