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Avoiding Aluminum Spikes During the Production of Conductor Metallizations

IP.com Disclosure Number: IPCOM000043902D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Bauer, HJ: AUTHOR [+2]

Abstract

It is known that when small contact holes are opened in a silicon nitride/silicon oxide double layer, a nitride overhang and a cavity may occur in the bottom oxide layer as a result of underetching. The present article proposes that, after the opening of the contact holes in the silicon nitride/silicon oxide double layer, Cr, AlCu and Al evaporation, respectively, be effected such that initially only part of the total metallization thickness is evaporated and the vacuum chamber is subsequently ventilated. By means of in-situ sputter cleaning, the oxide formed during ventilation is removed from the center area in the contact opening but is left intact on the Al underneath the silicon overhang. Subsequently, the metallization is evaporated to the desired thickness in the same vacuum chamber.

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Avoiding Aluminum Spikes During the Production of Conductor Metallizations

It is known that when small contact holes are opened in a silicon nitride/silicon oxide double layer, a nitride overhang and a cavity may occur in the bottom oxide layer as a result of underetching. The present article proposes that, after the opening of the contact holes in the silicon nitride/silicon oxide double layer, Cr, AlCu and Al evaporation, respectively, be effected such that initially only part of the total metallization thickness is evaporated and the vacuum chamber is subsequently ventilated. By means of in-situ sputter cleaning, the oxide formed during ventilation is removed from the center area in the contact opening but is left intact on the Al underneath the silicon overhang. Subsequently, the metallization is evaporated to the desired thickness in the same vacuum chamber. The above-described method, comprising the following steps, avoids Al spikes which are otherwise formed during the sintering of the metallization and which lead to yield losses. 1. The layout for wiring the metallization is such that the contact holes are covered completely. 2. The production of the lift-off matrix and the cleaning of the wafers are effected in a known manner. 3. The wafers are evaporated in a system described in * . In a first step, chromium is evaporated, using a pressure of
6.65 x 10-3 Pa and adding water vapor. In a second step, AlCu is evaporated at a pressure of 2.66 x 10-4 Pa up t...