Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – Insulated gate formation
Patent
1998-06-25
2000-02-15
Bowers, Charles
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
Insulated gate formation
438238, 438256, 438397, 438398, 438399, 438692, 438697, 438711, 438712, 438723, 438724, 438734, 438743, 438744, H01L 21306
Patent
active
060252553
ABSTRACT:
The practice of forming self-aligned contacts in MOSFETs using a silicon nitride gate sidewall and a silicon nitride gate cap has found wide acceptance, particularly in the manufacture of DRAMs, where bitline contacts are formed between two adjacent wordlines, each having a nitride sidewall. The contact etch requires a an RIE etch having a high oxide
itride selectivity. Current etchants rely upon the formation of a polymer over nitride surfaces which enhances oxide
itride selectivity. However, for contact widths of less than 0.35 microns, as are encountered in high density DRAMs, the amount of polymer formation required to attain a high selectivity causes the contact opening to close over with polymer before the opening is completely etched. This results in opens or unacceptably resistive contacts. On the other hand, if the etchant is adjusted to produce too little polymer, the nitride cap and sidewalls are thinned or etched through, producing gate to source/drain shorts. The invention describes a two step etching process whereby the contact opening is initially etched at high selectivity, and then, as the contact channel narrows, the polymer formation rate is reduced to prevent polymer pinch off and assure clearance of insulator in the contact area. The method performs both etch steps and the polymer and photoresist removal successively within the same RIE tool.
REFERENCES:
patent: 5286344 (1994-02-01), Blalock et al.
patent: 5423945 (1995-06-01), Marks et al.
patent: 5431778 (1995-07-01), Dahm et al.
patent: 5780338 (1998-07-01), Jeng et al.
patent: 5795820 (1998-08-01), Kepler
patent: 5869404 (1999-02-01), Kim et al.
patent: 5872063 (1999-02-01), Chao et al.
patent: 5920796 (1999-07-01), Wang et al.
Chen Bi-Ling
Jerry Erik S.
Lee Daniel Hao-Tien
Ackerman Stephen B.
Bowers Charles
Nguyen Thanh
Saile George O.
Vanguard International Semiconductor Corporation
LandOfFree
Two-step etching process for forming self-aligned contacts does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Two-step etching process for forming self-aligned contacts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-step etching process for forming self-aligned contacts will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1905524