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Method of Forming Void Free Fillings for Contact Holes

IP.com Disclosure Number: IPCOM000049377D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Thirl, KP: AUTHOR [+3]

Abstract

Contact holes in an Si(3)N(4) and an underlying SiO(2) layer, with thee Si(3)N(4) overhanging the edge of the SiO(2), are filled by evaporating the conductor material after the overhanging Si(3)N(4) has been removed, using a sputter-deposited Pt layer as an etch mask.

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Method of Forming Void Free Fillings for Contact Holes

Contact holes in an Si(3)N(4) and an underlying SiO(2) layer, with thee Si(3)N(4) overhanging the edge of the SiO(2), are filled by evaporating the conductor material after the overhanging Si(3)N(4) has been removed, using a sputter-deposited Pt layer as an etch mask.

The contact hole to be filled is etched into Si(3)N(4) layer 3 and SiO(2) layer 2 deposited on silicon body 1, underetching Si(3)N(4) layer 3. On top of this structure, a Pt layer 4 is sputter-deposited, covering Si(3)N(4) layer 3 and the whole bottom of the contact hole (Fig. 1). Using Pt layer 4 as an etch mask, overhang 5 of Si(3)N(4) layer 3 is removed by wet etching (Fig. 2). By means of a heat treatment, PtSi 6 is formed in those areas where Pt layer 4 overlies the silicon. The Pt that has not reacted is removed with aqua regia. Finally, blanket layers 7, 8 of conductor metal, such as Cr, Al/Cu or both, are deposited by evaporation and personalized.

The method not only prevents the formation of Al spikes in the contact areas but also the accumulation of contaminants between the filling and the sidewalls of the contact holes.

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