Method of forming contact openings for a transistor,申请号US201514797325-传众专利搜索

Method of forming contact openings for a transistor

申请公布号：US9484217(B2)

申请号：US201514797325

申请日期：2015.07.13

申请公布日期：2016.11.01

申请人：

Commissariat A L'Energie Atomique et aux Energies Alternatives

发明人：Posseme Nicolas

分类号：H01L21/311;H01L21/768;H01L29/16;H01L21/033;H01L29/66;H01L29/161;H01L21/265;H01L21/02;H01L21/3115;H01L29/417

主分类号：H01L21/311

代理机构：

Oblon, McClelland, Maier & Neustadt, L.L.P.

代理人：Oblon, McClelland, Maier & Neustadt, L.L.P.

地址：Paris FR

摘要：A method for making contact openings for connecting a transistor from a stack of layers comprising an active layer made of a semi-conductor material, a silicide layer on the top of the active layer, a nitride-based layer on the top of the silicide layer, and an electrically insulating layer on the top of the nitride-based layer, includes opening for forming, in the insulating layer, an exposing opening on the nitride-based layer and delimited by flanks of the insulating layer, and removing the nitride-based layer by modifying the nitride-based layer at the opening using plasma wherein CxHy is introduced where x is the proportion of carbon and y is the proportion of hydrogen ions and comprising ions heavier than hydrogen. The conditions of plasma being so chosen as to modify a portion of the nitride-based layer and to form a protective carbon film on the flanks of the insulating layer.

主权项：1. A method for making contact openings for connecting a field effect transistor from a stack of layers comprising at least an active layer made of a semi-conductor material, a silicide layer on the top of the active layer, a nitride-based layer on the top of the silicide layer, and an electrically insulating layer on the top of the nitride-based layer, the method comprising: opening the insulating layer for forming in the insulating layer at least an opening exposing the nitride-based layer and delimited by flanks of the insulating layer; removing the nitride-based layer at the opening so as to expose the silicide layer wherein the removing the nitride-based layer at the opening comprises: modifying the nitride-based layer at the opening by putting the nitride-based layer in contact with a plasma wherein CxHy is introduced, where x is the proportion of carbon and y is the proportion of hydrogen ions, with the plasma comprising at least hydrogen-based ions provided by CxHy, chemical species containing carbon provided by CxHy and ions heavier than hydrogen, the conditions of plasma, the concentration of CxHy, the ion energy, and a main implantation direction being chosen such that: at least a part of hydrogen-based ions provided by CxHy are implanted in a portion of the nitride-based layer at the opening and thus forming a modified portion of the nitride-based layer,at least a part of the plasma chemical species containing carbon provided by CxHy form a carbon film on said flanks of the insulating layer, andthe ions heavier than hydrogen prevent said carbon-containing plasma chemical species from forming a carbon film at a bottom of the opening; andremoving the modified portion of the nitride-based layer using a selective etching of the nitride-based modified portion relative to non-modified portions of the nitride-based layer and relative to the carbon film.