Method of forming multilayer aluminum wiring in semiconductor IC
AssigneeYamaha Corporation
InventorSuguru Tabara
Life of this patent
Estimating the term…
Abstract
A lower wiring layer is formed on an insulating film 12 covering a semiconductor substrate 10. The wiring layer 14 has a laminated structure of a barrier metal layer such as Wsi.sub.2, an Al or Al alloy layer, and a cap metal layer such as WSi.sub.2 formed in this order from the bottom. The cap metal layer is caused to contain conductive material such as Al by using an ion injection method or the like. After forming an insulating film covering the wiring layer, a contact hole is formed in the insulating film by a dry etching process using a resist layer as a mask. The dry etching process uses a fluorine based gas such as CHF.sub.3 as the etching gas. With this etching gas, fluoride such as Al fluoride (AlF.sub.3) is generated to suppress the etching of the cap metal layer.
Claims24
A method of forming a multilayered wiring comprising the steps of:
- forming a lower wiring layer on an insulating surface of a substrate, said lower wiring layer comprising a conduction layer consisting of Al or an Al alloy and a cap metal layer formed on said conduction layer, wherein said cap metal layer consists essentially of materials that are readily etched by a fluorine based plasma gas;
- introducing a conductive material to said cap metal layer that reacts in a fluorine based plasma gas to form a material that is not readily etched by a fluorine based plasma gas;
- forming an insulating film on said insulating surface of said substrate, said insulating film overlying said lower wiring layer;
- selectively etching said insulating film by a dry etching process using a fluorine based gas as an etching gas to form a contact hole at a position corresponding to a contact area of said lower wiring layer;
- forming an upper wiring layer on said insulating film and connecting said upper wiring layer to said lower wiring layer via said contact hole.
A method of forming a multilayered wiring comprising the steps of:
- forming a lower wiring layer on an insulating surface of a substrate, the lower wiring layer including a conduction layer formed of Al or an Al alloy and a cap metal layer formed on the conduction layer;
- injecting metal ions into the cap metal layer, after the step of forming a lower wiring layer, the metal being different from any constituent element of the cap metal layer;
- forming an insulating film to cover the lower wiring layer;
- selectively etching the insulating film by a dry etching process using a fluorine based gas as an etching gas, forming a contact hole through the insulating layer at a position corresponding to a contact area of the lower wiring layer, the metal ions injected into the cap metal layer being capable of reacting with fluorine contained in the etching gas to form a fluoride on a surface of the cap metal layer, the fluorine suppressing etching of the cap metal layer;
- forming an upper wiring layer on the insulating film;
- and
- connecting the upper wiring layer to the lower wiring layer via the contact hole.
A method of manufacturing a multilayered wiring structure having an upper wiring layer and a lower wiring layer, comprising the steps of:
- (a) forming the lower wiring layer having a first sublayer which acts as a primary conduction path within the lower wiring layer and a second sublayer that prevents the formation of defects in the first sublayer;
- (b) injecting ions of a metal into the second sublayer, the metal having a property of reacting with fluorine to form a fluoride having a low vapor pressure;
- (c) forming an interlevel insulating layer on the lower wiring layer;
- and
- (d ) selectively etching the interlevel insulating layer with a gas including fluorine as a constituent element, forming a contact hole through the interlevel insulating layer and exposing a part of the second sublayer to the gas,
- wherein the metal ions injected into the second sublayer react with fluorine in the gas to form a fluoride, suppressing etching of the second sublayer.
A method of manufacturing a multilayered wiring structure having an upper wiring layer and a lower wiring layer, comprising the steps of:
- (a) forming a lower wiring layer having a first sublayer serving as a main conductive layer within the lower wiring layer, the first sublayer being made of first metal or alloy thereof, and a second sublayer for preventing the formation of defects in the first sublayer, the second sublayer being made of a second metal which is different from the first metal;
- (b) injecting ions of the first metal into the second sublayer, the metal having a property of reacting with fluorine to form a fluoride having a low vapor
- (c) forming an interlevel insulating layer on the lower wiring layer;
- and
- (d) selectively etching the interlevel insulating layer with a gas including fluorine as a constituent element, forming a contact hole through the interlevel insulating layer and exposing a part of the second sublayer to the gas, the metal injected into the second sublayer reacting with fluorine included in the gas to form fluoride which suppresses etching of the second sublayer.
Dependencies are inferred from the claim text.