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Anneal Before Etch (ABE) Process Disclosure Number: IPCOM000227752D
Publication Date: 2013-May-14
Document File: 2 page(s) / 41K

Publishing Venue

The Prior Art Database


Disclosed is a method to perform the anneal after metal deposition in order to prevent extrusions being formed in the Alumimum Metal Stack.

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Anneal Before Etch (ABE) Process

In semiconductors, annealing is used to form TiAl3 above and below the aluminum that forms the top and bottom redundancy layers. Metal annealing is currently performed after metal etch, which, due to the unique metallurgy of the more advanced aluminum Complimentary Metal-Oxide Semiconductor (CMOS) processes used for wireless applications, leads to the formation of metal extrusions.

Instead of performing the anneal after etch, the novel approach is to perform the anneal after metal deposition. This prevents aluminum extrusion formation. Another aspect of this disclosure is annealing before RIE prevents metal to via interface undercutting.

Typically, the anneal is performed after metal Reactive Ion Etching (RIE); however, doing so attacks the Ti at the metal to via interface. By annealing after metal deposition, the Ti reacts with aluminum forming TiAl3 which prevents Ti undercut during the metal RIE process. Annealing pre-RIE fixes the metal to via interface undercutting.

Figure 1: Proposed Process Flow: Anneal Before RIE

Figure 2: POR Process Flow


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