Planarization process for organic filling of deep trenches
US4665007A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1985 |
| Grant date | May 12, 1987 |
| Priority date | — |
| Expiry date | Aug 19, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76224
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Disclosed is a process for planarization of semiconductor structures having dielectric isolation regions. Specifically, the process is directed to planarization of an organic polyimide layer obtained following filling of deep trenches in a semiconductor substrate having high and low density trench regions with this material. After over-filling the trenches with the polyimide and obtaining a non-planar polyimide layer having a thickness much larger in the low trench density regions than that in the high density regions, a photoresist layer is applied thereover. The photoresist is then controllably exposed using a mask which is the complement or inverse of the mask used for imaging the trench patterns to obtain a thick blockout photoresist mask over the trenches and a thin wetting layer of photoresist over the remainder of the substrate. Next, by means of a thermal step, the blockout photoresist is caused to reflow to form a relatively thick photoresist layer over the high trench density regions and a thin photoresist layer over the low trench density regions, thereby exactly compensating for the non-planarity of the polyimide layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.