Hard mask method for transferring a multi-level photoresist pattern
US5821169A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 5, 1996 |
| Grant date | Oct 13, 1998 |
| Priority date | — |
| Expiry date | Aug 5, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2221/1021
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method is provided for forming intermediate levels in an integrated circuit dielectric during a damascene process using a hard mask layer to transfer the pattern of a photoresist mask having at least one intermediate thickness. The dielectric is covered with a hard mask layer, and the hard mask layer is covered with the photoresist mask. The photoresist mask pattern is transferred into the hard mask pattern so that the hard mask pattern has at least one intermediate thickness. The method forms an interconnect to a first depth in the dielectric through an opening in the hard mask pattern. The hard mask pattern is partially etched away in the area of the intermediate thickness to reveal a second dielectric surface area. The second dielectric surface area is etched to a second depth, less than the first depth. In this manner, vias can be formed to the first depth, and lines can be formed at a second depth to intersect the vias. The use of a relatively thin hard mask pattern reduces the degradation of vertical surface features, due to faceting, which generally occurs with the use of a thicker photoresist pattern. The method of the present invention allows a multi-level damascene proc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.