US5622636A
Expired / Lapsed
US
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Etch-ending point measuring method for wet-etch process
Assignee: SK Hynix Inc
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Filing: 1996-05-07
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Granted: 1997-04-22
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Expires: 2016-05-07
Abstract
Abstract A wet-etch method which determines a desired etch-ending point includes the steps of providing an etchant solution in a bath, perform a wet-etch process by dipping a material to be etched in the bath, measuring a PH variation value of the etchant solution during the wet-etch process, calculating a thickness variation value of the material by using the measured PH variation value, and stopping the wet-etch process when the thickness variation value reaches a preset value.
Inventors
- 👤 Yun J. Huh
- 👤 Sang J. Choi
- 👤 Suk B. Han
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:59
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/005; B24B37/013; H; H10; H10P; H10P50/00; H10P74/00; H10P74/23; H10P74/238
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
76 words
A wet-etching method which determines a desired etch-ending point comprising the steps of: providing an etchant solution in a bath; perform a wet-etch process by dipping a material to be etched in the bath; measuring a PH variation value of the etchant solution during the wet-etch process; calculating a thickness variation value of the material by using the measured PH variation value; and stopping the wet-etch process when the thickness variation value reaches a preset value.
Claim 2
Dependent Claim
76 words
A wet-etching method which determines a desired etch-ending point comprising the steps of: providing an etchant solution in a bath; perform a wet-etch process by dipping a material to be etched in the bath; measuring a PH variation value of the etchant solution during the wet-etch process; calculating a thickness variation value of the material by using the measured PH variation value; and stopping the wet-etch process when the thickness variation value reaches a preset value.
Claim 3
Dependent Claim
28 words
The wet-etching method as claimed in claim 1, wherein the material subjected to the wet-etch process comprises an insulating layer, and the etchant solution comprises an acid solution.
Claim 4
Dependent Claim
20 words
The wet-etching methods as claimed in claim 2, wherein the insulating layer comprises a silicon oxide layer (SiO 2 ).
Claim 5
Dependent Claim
17 words
The wet-etching method as claimed in claim 2, wherein the insulating layer comprises a silicon nitride layer.
Claim 6
Dependent Claim
34 words
The wet-etching method as claimed in claim 2, wherein the acid solution includes one of a H 3 PO 4 solution, an ammonium hydroxide (NH 4 OH) solution, and a hydrogen fluoride (HF) solution.
Claim 7
Dependent Claim
28 words
The wet-etching method are claimed in claim 1, wherein the material subjected to the wet-etch process comprises a semiconductor layer and the etchant solution comprises an acid solution.
Claim 8
Dependent Claim
14 words
The wet-etching method as claimed in claim 6, wherein the semiconductor layer comprises polysilicon.
Claim 9
Dependent Claim
19 words
The wet-etching method as claimed in claim 6, wherein the acid solution comprises a H 2 SO 4 solution.
Claim 10
Dependent Claim
80 words
The wet-etching method as claimed in claim 1, wherein the step of calculating the thickness variation value comprises the steps of: calculating a density variation value of hydrogen ions in the etchant solution by using the PH variation value; calculating a density variation value of the material subjected to the wet-etch process by using the density variation value of the hydrogen ions; and calculating the thickness variation value of the material by using the density variation value of the material.
Claim 11
Dependent Claim
30 words
The wet-etching method as claimed in claim 9, wherein the PH variation value (ΔPH) and density variation value of the hydrogen ions (ΔH) have a relation of ΔH=10 - Δph.
Claim 12
Dependent Claim
55 words
The wet-etching method as claimed in claim 9, wherein the thickness variation value is obtained by multiplying the density variation value of the material by a molecular weight of the material, a volume of the wet-etchant solution filling in the bath, the density of the material, and an area of the material to be etched.
Claim 13
Dependent Claim
35 words
The wet-etching method as claimed in claim 9, wherein the density variation value of the material is one-half of the density variation value of the hydrogen ions when the material is the silicon oxide layer.
Claim 14
Dependent Claim
33 words
The wet-etching method as claimed in claim 9, wherein the density variation value of the polysilicon is one-third of the density variation value or the hydrogen ions when the material is the polysilicon.
Claim 15
Dependent Claim
16 words
The wet-etching method as claimed in claim 1, wherein the PH variation value is measured continuously.
Claim 16
Dependent Claim
16 words
The wet-etching method as claimed in claim 1, wherein the PH variation value is measured discretely.
Claim 17
Dependent Claim
59 words
An etch-ending point measuring method for a wet etch process comprising the steps of: measuring a PH variation value of a etchant solution during the wet etch process; calculating a thickness variation value of a material to be etched by using the PH variation value; and determining an etch-ending point when the thickness variation value reaches a preset value.
Claim 18
Dependent Claim
59 words
An etch-ending point measuring method for a wet etch process comprising the steps of: measuring a PH variation value of a etchant solution during the wet etch process; calculating a thickness variation value of a material to be etched by using the PH variation value; and determining an etch-ending point when the thickness variation value reaches a preset value.
Claim 19
Dependent Claim
28 words
The etch-ending point measuring method as claimed in claim 16, wherein the material to be etched comprises an insulating layer and the etchant solution comprises an acid solution.
Claim 20
Dependent Claim
26 words
The etch-ending point measuring method as claimed in claim 17, wherein the insulating layer includes one of a silicon oxide layer and a silicon nitride layer.
Claim 21
Dependent Claim
36 words
The etch-ending point measuring method as claimed in claim 17, wherein the acid solution includes one of a H 3 PO 4 solution, an ammonium hydroxide (NH 4 OH) solution, and a hydrogen fluoride (HF) solution.
Claim 22
Dependent Claim
28 words
The etch-ending point measuring method as claimed in claim 16, wherein the material to be etched, comprises a semiconductor layer and the etchant solution comprises an acid solution.
Claim 23
Dependent Claim
16 words
The etch-ending point measuring method as claimed in claim 20, wherein the semiconductor layer comprises polysilicon.
Claim 24
Dependent Claim
21 words
The etch-ending point measuring method as claimed in claim 20, wherein the acid solution comprises an H 2 SO 4 solution.
Claim 25
Dependent Claim
18 words
The etch-ending point measuring method as claimed in claim 16, wherein the PH variation value is measured continuously.
Claim 26
Dependent Claim
18 words
The etch-ending point measuring method as claimed in claim 16, wherein the PH variation value is measured discretely.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-04-21 | 2000-10-21 | 2001-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-21 | 2004-10-21 | 2005-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-21 | 2008-10-21 | 2009-04-22 | $7700.00 | Window Closed / Lapsed |