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Process for Metal Patterning Using Silicon Layer Mask Defined by Reactive Ion Etching Through Photoresist Pattern

IP.com Disclosure Number: IPCOM000050485D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Aboelfotoh, MO: AUTHOR [+3]

Abstract

During the final steps of integrated circuit fabrication, the connection to other devices is usually formed by depositing and patterning a layer of aluminum doped with both copper and silicon. The copper-doped aluminum layer is formed into a pattern of conductors by etching through a mask formed by an overlying layer of silicon. The silicon layer is formed to a desired mask configuration by a dry etching process, such as reactive ion etching, through a photoresist pattern. The process gives good line definition and provides high yield.

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Process for Metal Patterning Using Silicon Layer Mask Defined by Reactive Ion Etching Through Photoresist Pattern

During the final steps of integrated circuit fabrication, the connection to other devices is usually formed by depositing and patterning a layer of aluminum doped with both copper and silicon. The copper-doped aluminum layer is formed into a pattern of conductors by etching through a mask formed by an overlying layer of silicon. The silicon layer is formed to a desired mask configuration by a dry etching process, such as reactive ion etching, through a photoresist pattern. The process gives good line definition and provides high yield.

As the drawing shows, a copper-doped aluminum layer is deposited and then etched to a pattern of conductors to provide final contact to other devices. The mask for the etching step is formed by a first layer of silicon and a second layer of a photoresist. The photoresist is exposed according to the desired conductor pattern and is developed to expose the underlying layer of silicon where the metal is to be removed. The exposed areas of silicon are then removed by a dry etching process, such as reactive ion etching in CF(4)-oxygen gas mixture. The resulting photoresist-silicon structure is then used as a mask for patterning the underlying copper-doped aluminum layer using conventional wet etching. This is followed by a final annealing step after the removal of the photoresist layer to allow silicon to diffuse into the un...