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Materials, Masking and Etching Technique for Fabricating Semiconductor Stud-Up Interconnections

IP.com Disclosure Number: IPCOM000035830D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 68K

Publishing Venue

IBM

Related People

Cronin, JE: AUTHOR [+3]

Abstract

Stud-up technology uses a single metal which is deposited, imaged (masked and etched) for a line and then the same conductor material is imaged again. Through a controlled etch process, the interconnect "stud- up" system in the wiring pattern is then formed. Because this is a repetitive sequence, particularly in a logic semiconductor fabrication process, simplified methods are needed. Two techniques are shown for forming a stud-up system in the single conductor layer. One technique uses an etch-stop means and one does not. (Image Omitted)

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Materials, Masking and Etching Technique for Fabricating Semiconductor Stud-Up Interconnections

Stud-up technology uses a single metal which is deposited, imaged (masked and etched) for a line and then the same conductor material is imaged again. Through a controlled etch process, the interconnect "stud- up" system in the wiring pattern is then formed. Because this is a repetitive sequence, particularly in a logic semiconductor fabrication process, simplified methods are needed. Two techniques are shown for forming a stud-up system in the single conductor layer. One technique uses an etch-stop means and one does not.

(Image Omitted)

Beneath a single photoresist layer and above a single conductor layer, a plurality of alternating thin and thick underlayers which are natural etch-stops to each other are patterned to form a masking structure. The non-erodible mask layers (NEMs), providing the masking structure, are formed through an etch sequence utilized to form both a wiring pattern and a stud-up interconnect system in the single underlaying conductor layer. The layers are selected such that both may be etched in one etchant, and one can be etched without etching the other in a second etchant.

Referring to Fig. 1, six layers of material and the approximate thickness of each film is shown. The films are deposited in situ in a sputtering tool requiring two targets and an oxygen gas line.

A photoresist conductor line mask is applied over the layers of material to define both the aluminum tri-oxide Al2O3 and tungsten W simultaneously. A sputter etch of the Al2O3 is followed by a chemical etch of the W before the mask is stripped, as shown in Fig. 2. Next a mask is used to define the Al2O3 film. The resulting Al2O3 (stud mask) and W (line mask...