Method for forming an interconnection in a semiconductor element
View Patent ↗There is disclosed a method for forming an interconnection in the semiconductor element, including a process for forming a groove 117 on an underlying substrate so as to correspond to the designed pattern, a process for forming an underlayer to improve crystalline of an interconnection which will be formed in the succeeding stage on said underlying substrate with said groove, a process for forming a thin film of the interconnection material, a heat-treatment process to fill the said groove with the thin film of the interconnection material formed on the underlying substrate, and a process for forming the interconnection by polishing the surface of the thin film by predetermined quantity.
1. A method for forming a semiconductor element, comprising:
forming a groove having a bottom wall and side walls in a surface of an insulating film;
sequentially forming a first layer and a second layer over the surface of the insulating film and over the bottom wall and side walls of the groove in a first chamber, wherein the first layer is made of a high melting-point metal and the second layer is made of a nitride of the high melting-point metal, wherein a thickness of the first layer is formed to be thinner than a thickness of the second layer, wherein a combined thickness of the first and second layers formed over the side walls of the groove is thinner than a combined thickness of the first and second layers formed over the surface of the insulating film, and wherein the combined thickness of the first and second layers formed over the side walls of the groove is thinner than a combined thickness of the first and second layers formed over the bottom wall of the groove;
forming a conductive layer over the surface of the insulating film and within the groove in a second chamber, wherein the conductive layer includes copper, and wherein the first and second layers are interposed between the conductive layer and the insulating film; and
chemically and/or mechanically polishing the conductive layer to remove the conductive layer formed over the surface of the insulating film.
2. The method as claimed in claim 1 , wherein said polishing further removes the first and second layers over the surface of the insulating film.
3. The method as claimed in claim 1 , wherein the high melting-point metal is titanium.
4. The method as claimed in claim 2 , wherein the high melting-point is titanium.
5. The method as claimed in claim 1 , wherein the first and second layers are formed by respective first and second sputtering processes.
6. The method as claimed in claim 5 , wherein the second layer is formed by discharging a nitride gas during the second sputtering process.
7. The method as claimed in claim 1 , wherein the first and second layers are formed by respective first and second ion metal plasma sputtering processes.
8. The method as claimed in claim 7 , wherein the second layer is formed by discharging a nitride gas during the second ion metal plasma sputtering process.