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US6066529A
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Method for enlarging surface area of a plurality of hemi-spherical grains on the surface of a semiconductor chip
Assignee: Promos Technologies Inc
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Filing: 1998-11-23
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Granted: 2000-05-23
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Expires: 2018-11-23
Abstract
Abstract The present invention provides a method for enlarging the surface area of hemi-spherical grains on the surface of a semiconductor chip. The hemi-spherical grain structure is formed by combining a poly-silicon layer with an underlying amorphous silicon layer. In processing, the two layers are etched with a corrosive solution that etches the amorphous silicon layer at a higher rate than it etches the poly-silicon layer. In this way, a ring-shaped slot forms at the bottom of each hemi-spherical grain thus increasing the total surface area of the hemi-spherical grain structure. Furthermore, surface area of the storage node is increased and the cell capacitor capacitance increases in excess of 15%.
Inventors
- 👤 Ping-Wei Lin
- 👤 Jui-Ping Li
- 👤 Ming-Kuan Kao
- 👤 Yi-Fu Chung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:45
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10D1/711; H10D1/712; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10D1/716; H10P; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
111 words
A method for enlarging surface area of a hemi-spherical grain structure on the surface of a semiconductor chip, the hemi-spherical grain structure being formed by a combination of a poly-silicon layer containing a plurality of hemi-spherical grains on its upper surface and an amorphous silicon layer under the poly-silicon layer, the method comprising: etching the poly-silicon layer and amorphous silicon layer by using a corrosive solution that etches the amorphous silicon layer at a higher rate than it etches the poly-silicon layer so that the amorphous silicon layer around the bottom of each hemi-spherical grain forms a ring-shaped slot and the total surface area of the hemi-spherical grain structure is increased.
Claim 2
Independent Claim
111 words
A method for enlarging surface area of a hemi-spherical grain structure on the surface of a semiconductor chip, the hemi-spherical grain structure being formed by a combination of a poly-silicon layer containing a plurality of hemi-spherical grains on its upper surface and an amorphous silicon layer under the poly-silicon layer, the method comprising: etching the poly-silicon layer and amorphous silicon layer by using a corrosive solution that etches the amorphous silicon layer at a higher rate than it etches the poly-silicon layer so that the amorphous silicon layer around the bottom of each hemi-spherical grain forms a ring-shaped slot and the total surface area of the hemi-spherical grain structure is increased.
Claim 3
Dependent Claim
40 words
The method of claim 1 wherein the corrosive solution also etches the interface between neighboring hemi-spherical grains which are stuck together and forms a plurality of separated hemi-spherical grains thereby increasing the total surface area of the hemi-spherical grain structure.
Claim 4
Dependent Claim
15 words
The method of claim 1 is used for forming a storage node of a capacitor.
Claim 5
Dependent Claim
55 words
The method of claim 1 wherein the semiconductor chip further comprises a native oxide layer on the surface of the poly-silicon layer and prior to etching the poly-silicon layer and amorphous silicon layer, the method further comprises: stripping off the native oxide layer on the surface of the poly-silicon layer by using an organic solution.
Claim 6
Dependent Claim
13 words
The method of claim 4 wherein the organic solution comprises hydrofluoric acid (HF).
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein the corrosive solution comprises phosphoric acid (H 3 PO 4 ).
Claim 8
Dependent Claim
39 words
The method of claim 6 wherein after etching the poly-silicon layer and amorphous silicon layer, the method further comprises: using another corrosive solution to polish and clean the surface of each of the hemi-spherical grains and the ring-shaped slots.
Claim 9
Dependent Claim
24 words
The method of claim 7 wherein said another corrosive solution contains ammonia (NH 4 OH), hydrogen peroxide (H 2 O 2 ) and water.
Claim 10
Dependent Claim
78 words
The method of claim 1 wherein the corrosive solution comprises a first corrosive solution and a second corrosive solution, the method comprises: using the first corrosive solution to etch the poly-silicon layer and amorphous silicon layer so as to form the ring-shaped slot on the amorphous silicon layer around the bottom of each of the hemi-spherical grains; using the second corrosive solution to polish and clean the surface of each of the hemi-spherical grains and the ring-shaped slots.
Claim 11
Dependent Claim
18 words
The method of claim 9 wherein the first corrosive solution comprises phosphoric acid (H 3 PO 4 ).
Claim 12
Dependent Claim
24 words
The method of claim 9 wherein the second corrosive solution contains ammonia (NH 4 OH), hydrogen peroxide (H 2 O 2 ) and water.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-05-23 | 2003-11-22 | 2004-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-05-23 | 2007-11-22 | 2008-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-05-23 | 2011-11-22 | 2012-05-23 | $7700.00 | Window Closed / Lapsed |