US5246879A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming nanometer-scale trenches and holes
Assignee: United States Department of the Navy
•
Filing: 1991-10-24
•
Granted: 1993-09-21
•
Expires: 2011-10-24
Abstract
Abstract Nanometer thick metallic layers are fabricated on trenches or holes (espelly vias) within a substrate by depositing, by thermal decomposition of a volatile metal-containing precursor gas in the presence of a carrier gas at low pressure, a metallic layer on a substrate surface on which one or more trenches or holes are formed. The metallic layer thus formed has an extremely small grain size, which permits the attainment of very high spatial resolution and thus permits the formation of extremely small trenches and holes, increasing the attainable memory/circuit density. This invention is useful in the fabrication of ultra-high density trench capacitors and ULSI microelectronic circuits.
Inventors
- 👤 David S. Y. Hsu
- 👤 Henry F. Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:25
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/063; H10P; H10P14/00; H10P14/40; H10P14/42; H10P14/43; H10P50/00; H10P50/69; H10P50/691; H10P50/693; H10P50/695; H10P76/00; H10P76/40; H10P76/408; H10P76/4085; H10P76/4088; H10W20/0636; Y; Y10; Y10S; Y10S148/00; Y10S148/105; Y10S148/111; Y10S438/00; Y10S438/942; Y10S438/947
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
113 words
A method for microfabricating a metallization upon a hole or trench in a horizontal surface of a substrate, said hole or trench having at least one vertical surface, comprising the steps of: providing a substrate having at least one hole or trench thereon; depositing a layer of metal having a thickness of less than 0.1 micron on said at least one vertical surface by thermal decomposition of a volatile metal-containing precursor gas and a carrier gas, said carrier gas having a partial pressure of less than about 10 -2 Torr, and the partial pressure of said carrier gas being about 5 to 10 times higher than the partial pressure of the precursor gas.
Claim 2
Independent Claim
113 words
A method for microfabricating a metallization upon a hole or trench in a horizontal surface of a substrate, said hole or trench having at least one vertical surface, comprising the steps of: providing a substrate having at least one hole or trench thereon; depositing a layer of metal having a thickness of less than 0.1 micron on said at least one vertical surface by thermal decomposition of a volatile metal-containing precursor gas and a carrier gas, said carrier gas having a partial pressure of less than about 10 -2 Torr, and the partial pressure of said carrier gas being about 5 to 10 times higher than the partial pressure of the precursor gas.
Claim 3
Dependent Claim
29 words
The method of claim 1, wherein said hole or trench includes a horizontal surface and said layer of metal is deposited by said thermal decomposition upon said horizontal surface.
Claim 4
Dependent Claim
19 words
The method of claim 1, wherein said at least one vertical surface of said substrate is SiO 2 .
Claim 5
Dependent Claim
16 words
The method of claim 1, wherein said metal layer is deposited under chemical beam epitaxy conditions.
Claim 6
Dependent Claim
13 words
The method of claim 1, wherein said substrate has at least one via.
Claim 7
Dependent Claim
34 words
The method of claim 1, wherein said metal layer is deposited by thermal decomposition of said volatile metal-containing precursor gas is selected from the group consisting of inorganic metal coordination compounds and organometallic compounds.
Claim 8
Dependent Claim
13 words
The method of claim 6, wherein said precursor gas contains PF 3 ligands.
Claim 9
Dependent Claim
11 words
The method of claim 6, wherein said precursor gas contains platinum.
Claim 10
Dependent Claim
82 words
The method of claim 6, wherein said precursor gas is selected from the group consisting of Pt(PF 3 ) 4 , Ni(PF 3 ) 4 , Pd(PF 3 ) 4 , Fe(PF 3 ) 5 , W(PF 3 ) 6 , Cr(PF 3 ) 6 , Mo(PF 3 ) 6 , Co(PF 3 ) 6 , Ru(PF 3 ) 5 , Rh 2 (PF 3 ) 8 , Re 2 (PF 3 ) 10 and Ir 2 (PF 3 ) 8 .
Claim 11
Dependent Claim
11 words
The method of claim 6, wherein said carrier gas is hydrogen.
Claim 12
Dependent Claim
22 words
The method of claim 6, wherein said precursor gas has a vapor pressure at room temperature of at least 10 -7 Torr.
Claim 13
Dependent Claim
24 words
The method of claim 6, wherein the partial pressures of said precursor gas and said carrier gas are less than about 10 -4 Torr.
Claim 14
Dependent Claim
86 words
The method of claim 1, further comprising the step of applying a thermal gradient between a top and bottom of said hole or trench during said thermal decomposition, the temperature at said bottom being higher than the temperature at said top, wherein the rate of thermal decomposition of said precursor at said bottom is increased sufficiently with respect to the rate of thermal decomposition of said precursor at said top so that said deposited metal layer on said hole or trench is of essentially uniform thickness.
Claim 15
Dependent Claim
29 words
The method of claim 13, wherein said hole or trench includes a horizontal surface and said layer of metal is deposited by said thermal decomposition upon said horizontal surface.
Claim 16
Dependent Claim
13 words
The method of claim 14, wherein said precursor gas contains PF 3 ligands.
Claim 17
Dependent Claim
11 words
The method of claim 14, wherein said precursor gas contains platinum.
Claim 18
Dependent Claim
82 words
The method of claim 14, wherein said precursor gas is selected from the group consisting of Pt(PF 3 ) 4 , Ni(PF 3 ) 4 , Pd(PF 3 ) 4 , Fe(PF 3 ) 5 , W(PF 3 ) 6 , Cr(PF 3 ) 6 , Mo(PF 3 ) 6 , Co(PF 3 ) 6 , Ru(PF 3 ) 5 , Rh 2 (PF 3 ) 5 , Re 2 (PF 3 ) 10 and Ir 2 (PF 3 ) 8 .
Claim 19
Dependent Claim
18 words
The method of claim 1, wherein said hole or trench has a width of less than 1000 angstroms.
Claim 20
Dependent Claim
29 words
The method of claim 18, wherein the ratio of the depth of said trench of hole to the width of said trench or hole is at least about 3:1.
Claim 21
Dependent Claim
38 words
The method of claim 1, wherein said substrate is a chip into which said trenches have been cut to increase the surface are of a trench capacitor fabricated from said chip and used as dynamic random access memory.
Claim 22
Dependent Claim
24 words
The method of claim 1, further comprising the step of depositing an additional metal upon said deposited metal layer to provide a multilayer structure.
Claim 23
Dependent Claim
46 words
The method of claim 1, wherein said substrate is silicon, said substrate is at a temperature of above 300° C. during said depositing step, and silicon from said substrate diffuses into said deposited metal layer and reacts with said layer of metal to form metal silicide.
References Cited (Backward Citations)
US4570328A
Cited
US4608271A
Cited
US4957880A
Cited
US5071789A
Cited
US4874719A
Cited
US5071788A
Cited
EP0338206A1
Cited
US5108952A
Cited
US4920012A
Cited
US5110760A
Cited
US5096737A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-20 | 1997-03-22 | 1997-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-20 | 2001-03-22 | 2001-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-20 | 2005-03-22 | 2005-09-21 | $7700.00 | Window Closed / Lapsed |