Browse Prior Art Database

Protection of Aluminum from HF Etch by Addition of Permanganate

IP.com Disclosure Number: IPCOM000092709D
Original Publication Date: 1967-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Kaplan, LH: AUTHOR

Abstract

The technique forms Via holes in a silicon dioxide layer in which a permanganate salt is added in proper concentration to buffered HF etchant. This avoids the possibility of metal-to-substrate shorts.

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Protection of Aluminum from HF Etch by Addition of Permanganate

The technique forms Via holes in a silicon dioxide layer in which a permanganate salt is added in proper concentration to buffered HF etchant. This avoids the possibility of metal-to-substrate shorts.

A buffered HF solution is employed to etch Via hole 1 as defined by photoresist layer 3 in SiO(2) layer 5. In previous techniques, underlying layer 7 of aluminum is often penetrated by the etchant so that the underlying SiO(2) layer 9 is attacked. Thus the possibility of shorting an additional layer of aluminum, not shown, deposited within Via hole 1 to semiconductor substrate 11 is inc reased.

The addition of a permanganate salt to the buffered HF solution, e. g., 5 grams/liter of KMnO(4), minimizes attack on layer 7. The concentration of the permanganate salt is selected to prevent attack on layer 7 without materially reducing the etch rate.

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