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Etch Completion Indication

IP.com Disclosure Number: IPCOM000090406D
Original Publication Date: 1969-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Fink, MS: AUTHOR [+2]

Abstract

The complete removal of a sputtered quartz layer over aluminum can be indicated with the use of fluorescein in a saturated solution with methyl alcohol. Fluorescein stains aluminum but does not stain quartz. This technique is particularly useful for determining the completion of via hole etching through a sputtered quartz passivating layer over aluminum conducting lines on integrated circuit devices. The devices are periodically removed from an etching bath and the via hole area is contacted with the fluorescein solution. If residual quartz is present, no staining of aluminum occurs. If the quartz is completely removed, a yellow stain occurs, which shows that the etching operation is complete. The fluorescein dye causes no subsequent effect on the aluminum. The yellow stain can be removed by rinsing with methyl alcohol.

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Etch Completion Indication

The complete removal of a sputtered quartz layer over aluminum can be indicated with the use of fluorescein in a saturated solution with methyl alcohol. Fluorescein stains aluminum but does not stain quartz. This technique is particularly useful for determining the completion of via hole etching through a sputtered quartz passivating layer over aluminum conducting lines on integrated circuit devices. The devices are periodically removed from an etching bath and the via hole area is contacted with the fluorescein solution. If residual quartz is present, no staining of aluminum occurs. If the quartz is completely removed, a yellow stain occurs, which shows that the etching operation is complete. The fluorescein dye causes no subsequent effect on the aluminum. The yellow stain can be removed by rinsing with methyl alcohol. The use of this process eliminates the necessity for subsequent reverse sputter etching to remove residual quartz from via holes. The selective staining technique can also be used to detect the presence of exposed aluminum due to such defects as glass damage and pinholes.

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