Patent US4113550A successfully refreshed from Google Patents.
US4113550A
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US
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Method for fabricating semiconductor device and etchant for polymer resin
Assignee: Hitachi Ltd
•
Filing: 1976-06-11
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Granted: 1978-09-12
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Expires: 1996-06-11
Abstract
Abstract A semiconductor device fabricated by forming a layer of semicured polyimide resin on a semiconductor body, forming a photoresist layer having a prescribed pattern on said semicured layer, immersing in an etchant consisting of hydrazine and ethylenediamine to said semicured layer through said prescribed pattern, whereby said semicured layer is precisely etched according to said prescribed pattern and prescribed surfaces of said semiconductor body are exposed, curing said semicured polyimide so as to form a layer of said polyimide resin, forming a metal layer on the surface of said polyimide and the prescribed surfaces of said body, and selectively etching said metal layer so as to form a prescribed pattern.
Inventors
- 👤 Atsushi Saiki
- 👤 Toshio Okubo
- 👤 Seiki Harada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:28
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/68; H10P14/683; H10P50/00; H10P50/20; H10P50/28; H10P50/286; H10P50/287; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081; H10W20/082; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0313; H05K1/032; H05K1/0346; H05K3/00; H05K3/0011; H05K3/0017
Claims Analysis
Total Claims: 85
Claim 1
Independent Claim
59 words
A method for fabricating a semiconductor device comprising the steps of: forming, on a body, a layer of semicured polymer resin selected from the group consisting of polyimide and polyimide-iso-indroquinazolinedione and semicured at 200°-250° C.; and contacting an etchant consisting essentially of hydrazine or hydrazine hydrate and at least one of polyamines shown by a chemical formula of NH.sub.2.R.NH.sub.2,
Claim 2
Independent Claim
59 words
A method for fabricating a semiconductor device comprising the steps of: forming, on a body, a layer of semicured polymer resin selected from the group consisting of polyimide and polyimide-iso-indroquinazolinedione and semicured at 200°-250° C.; and contacting an etchant consisting essentially of hydrazine or hydrazine hydrate and at least one of polyamines shown by a chemical formula of NH.sub.2.R.NH.sub.2,
Claim 3
Dependent Claim
44 words
wherein R is selected from divalent radicals having 2-6 carbon atoms, the temperature of said etchant being in a range from 20° C. to 30° C., to a prescribed portion of said semicured layer so as to form an opening at said prescribed portion.
Claim 4
Dependent Claim
44 words
wherein R is selected from divalent radicals having 2-6 carbon atoms, the temperature of said etchant being in a range from 20° C. to 30° C., to a prescribed portion of said semicured layer so as to form an opening at said prescribed portion.
Claim 5
Dependent Claim
39 words
A method for fabricating a semiconductor device according to claim 1, wherein said etchant consists essentially of hydrazine and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2 , wherein R is selected from divalent radicals having 2-6 carbon atoms.
Claim 6
Dependent Claim
27 words
A method for fabricating a semiconductor device according to claim 2, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediame, pentamethylenediamine and hexamethylenediamine.
Claim 7
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 3, wherein said polyamine is ethylenediamine.
Claim 8
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 2, wherein the volume % of said polyamine in said etchant is between 50 and 90%.
Claim 9
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 5, wherein said polyamine is ethylenediamine.
Claim 10
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 5, wherein the volume % of said polyamine in said etchant is between 60 and 85%.
Claim 11
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 7, wherein said polyamine is ethylenediamine.
Claim 12
Dependent Claim
52 words
A method for fabricating a semiconductor device according to claim 2, wherein said etchant consists of an aqueous solution of hydrazine and polyamine shown by a chemical formula of: NH.sub.2.R.NH.sub.2, wherein R is selected from divalent radicals having 2-6 carbon atoms containing more than 60 volume % hydrazine and polyamine, balance water.
Claim 13
Dependent Claim
27 words
A method for fabricating a semiconductor device according to claim 9, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 14
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 10, wherein said polyamine is ethylenediamine.
Claim 15
Dependent Claim
31 words
A method for fabricating a semiconductor device according to claim 2, which further comprises the step of curing said semicured polymer so as to form a layer of said polymer resin.
Claim 16
Dependent Claim
27 words
A method for fabricating a semiconductor device according to claim 12, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 17
Dependent Claim
25 words
A method for fabricating a semiconductor device according to claim 13, wherein said semicured polymer is cured at a temperature higher than about 250° C.
Claim 18
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 13, wherein said polyamine is ethylenediamine.
Claim 19
Dependent Claim
25 words
A method for fabricating a semiconductor device according to claim 15, wherein said semicured polymer is cured at a temperature higher than about 250° C.
Claim 20
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 16, wherein the volume % of said ethylenediamine in said etchant is between 50 and 90%.
Claim 21
Dependent Claim
23 words
A method for fabricating a semiconductor device according to claim 17, wherein the volume % of said ethylenediamine is between 60 and 85%.
Claim 22
Dependent Claim
57 words
A method for fabricating a semiconductor device according to claim 1, wherein said etchant consists of an aqueous solution of hydrazine and at least one of polyamines shown by a chemical formula of NH.sub.2.R.NH.sub.2, wherein R is selected from divalent radicals having 2-6 carbon atoms containing more than 60 volume % of hydrazine and polyamine, balance water.
Claim 23
Dependent Claim
27 words
A method for fabricating a semiconductor device according to claim 19, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 24
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 20, wherein said polyamine is ethylenediamine.
Claim 25
Dependent Claim
31 words
A method for fabricating a semiconductor device according to claim 1, which further comprises the step of curing said semicured polymer so as to form a layer of said polymer resin.
Claim 26
Dependent Claim
27 words
A method for fabricating a semiconductor device according to claim 22, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 27
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 23, wherein said polyamine is ethylenediamine.
Claim 28
Dependent Claim
25 words
A method for fabricating a semiconductor device according to claim 24, wherein said semicured polymer is cured at a temperature higher than about 250° C.
Claim 29
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 25, wherein the volume % of said ethylenediamine in said etchant is between 50 and 90%.
Claim 30
Dependent Claim
23 words
A method for fabricating a semiconductor device according to claim 26, wherein the volume % of said ethylenediamine is between 60 and 85%.
Claim 31
Independent Claim
179 words
A method for fabricating a semiconductor device comprising the steps of: forming at least one circuit element in a semiconductor body; forming an insulating layer on the surface of said body; forming at least one opening at prescribed portions of said insulating layer for exposing prescribed surfaces of said circuit element; forming a metal layer on the surface of said insulating layer and on said exposed surface of said circuit element; selectively etching said metal layer for forming a prescribed pattern of said metal layer, whereby prescribed surfaces of said insulating layer are exposed; forming a layer of semicured prepolymer resin selected from the group consisting of polyimide and polyimide-iso-indroquinazolinedione and semicured at 200°-250° C., on the surfaces of said metal layer and exposed surfaces of said insulating layer; forming a photoresist layer on the surface of said semicured prepolymer layer; forming a prescribed pattern on said photoresist layer, so that prescribed surfaces of said semicured prepolymer layer are exposed; contacting an etchant consisting essentially of hydrazine or hydrazine hydrate and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2,
Claim 32
Independent Claim
179 words
A method for fabricating a semiconductor device comprising the steps of: forming at least one circuit element in a semiconductor body; forming an insulating layer on the surface of said body; forming at least one opening at prescribed portions of said insulating layer for exposing prescribed surfaces of said circuit element; forming a metal layer on the surface of said insulating layer and on said exposed surface of said circuit element; selectively etching said metal layer for forming a prescribed pattern of said metal layer, whereby prescribed surfaces of said insulating layer are exposed; forming a layer of semicured prepolymer resin selected from the group consisting of polyimide and polyimide-iso-indroquinazolinedione and semicured at 200°-250° C., on the surfaces of said metal layer and exposed surfaces of said insulating layer; forming a photoresist layer on the surface of said semicured prepolymer layer; forming a prescribed pattern on said photoresist layer, so that prescribed surfaces of said semicured prepolymer layer are exposed; contacting an etchant consisting essentially of hydrazine or hydrazine hydrate and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2,
Claim 33
Dependent Claim
102 words
wherein R is selected from divalent radicals having 2-6 carbon atoms, the temperature of said etchant being in a range from 20° C. to 30° C. to the exposed surface of said prepolymer layer, so as to etch said prepolymer layer and to expose prescribed surfaces of said metal layer; removing said photoresist layer; curing said semicured prepolymer so as to form a cured layer of said polymer resin; forming another metal layer on the surface of said cured polymer resin layer and exposed surface of said metal layer; and etching said another metal layer so as to form a prescribed pattern.
Claim 34
Dependent Claim
102 words
wherein R is selected from divalent radicals having 2-6 carbon atoms, the temperature of said etchant being in a range from 20° C. to 30° C. to the exposed surface of said prepolymer layer, so as to etch said prepolymer layer and to expose prescribed surfaces of said metal layer; removing said photoresist layer; curing said semicured prepolymer so as to form a cured layer of said polymer resin; forming another metal layer on the surface of said cured polymer resin layer and exposed surface of said metal layer; and etching said another metal layer so as to form a prescribed pattern.
Claim 35
Dependent Claim
24 words
A method for fabricating a semiconductor device according to claim 28, wherein said prepolymer is cured at a temperature higher than about 250° C.
Claim 36
Dependent Claim
27 words
A method for fabricating a semiconductor device according to claim 29, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 37
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 30, wherein the volume % of said polyamine in said etchant is between 50 and 90%.
Claim 38
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 31, wherein the volume % of said polyamine in said etchant is between 60 and 85%.
Claim 39
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 29, wherein said polyamine is ethylenediamine.
Claim 40
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 33, wherein the volume % of said ethylenediamine in said etchant is between 50 and 90%.
Claim 41
Dependent Claim
23 words
A method for fabricating a semiconductor device according to claim 34, wherein the volume % of said ethylenediamine is between 60 and 85%.
Claim 42
Independent Claim
193 words
A method for fabricating a semiconductor device comprising the steps of: forming an insulating layer on a surface of a body; forming a layer of semicured prepolymer resin selected from the group consisting of polyimide and polyimideiso-indroquinazolinedione and semicured at 200°-250° C., on the surface of said insulating layer; forming a photoresist layer on the surface of said semicured polymer layer; forming a prescribed pattern on said photoresist layer, so that prescribed surfaces of said semicured polymer layer are exposed; contacting an etchant consisting essentially of hydrazine or hydrazine hydrate and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2, wherein R is selected from divalent radicals having 2-6 carbon atoms, the temperature of said etchant being in a range from 20° C. to 30° C. to the exposed surface of said prepolymer layer, so as to etch said prepolymer layer and to expose prescribed surfaces of said insulating layer; removing said photoresist layer; etching said insulating layer; curing said semicured polymer so as to form a layer of cured polymer resin; forming a metal layer on said cured polymer resin layer; and etching said metal layer so as to form a prescribed pattern.
Claim 43
Independent Claim
193 words
A method for fabricating a semiconductor device comprising the steps of: forming an insulating layer on a surface of a body; forming a layer of semicured prepolymer resin selected from the group consisting of polyimide and polyimideiso-indroquinazolinedione and semicured at 200°-250° C., on the surface of said insulating layer; forming a photoresist layer on the surface of said semicured polymer layer; forming a prescribed pattern on said photoresist layer, so that prescribed surfaces of said semicured polymer layer are exposed; contacting an etchant consisting essentially of hydrazine or hydrazine hydrate and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2, wherein R is selected from divalent radicals having 2-6 carbon atoms, the temperature of said etchant being in a range from 20° C. to 30° C. to the exposed surface of said prepolymer layer, so as to etch said prepolymer layer and to expose prescribed surfaces of said insulating layer; removing said photoresist layer; etching said insulating layer; curing said semicured polymer so as to form a layer of cured polymer resin; forming a metal layer on said cured polymer resin layer; and etching said metal layer so as to form a prescribed pattern.
Claim 44
Dependent Claim
25 words
A method for fabricating a semiconductor device according to claim 36, wherein the semicured prepolymer is cured at a temperature higher than about 250° C.
Claim 45
Dependent Claim
27 words
A method for fabricating a semiconductor device according to claim 37, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 46
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 38, wherein the volume % of said polyamine in said etchant is between 50 and 90%.
Claim 47
Dependent Claim
23 words
A method for fabricating a semiconductor device according to claim 39, wherein the volume % of said polyamine is between 60 and 85%.
Claim 48
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 37, wherein said polyamine is ethylenediamine.
Claim 49
Dependent Claim
23 words
A method for fabricating a semiconductor device according to claim 41, wherein the volume % of said ethylenediamine is between 50 and 90%.
Claim 50
Dependent Claim
23 words
A method for fabricating a semiconductor device according to claim 42, wherein the volume % of said ethylenediamine is between 60 and 85%.
Claim 51
Independent Claim
187 words
A method for fabricating a semiconductor device comprising the steps of: forming a first metal layer on an insulating layer; etching said metal layer so as to form a prescribed pattern; forming a layer of semicured prepolymer resin selected from the group consisting of polyimide and polyimideiso-indroquinazolinedione and semicured at 200°-250° C., on the surface of said prescribed pattern and on exposed surfaces of said insulating layer; contacting an etchant consisting essentially of hydrazine or hydrazine hydrate and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2, wherein R is selected from divalent radicals having 2-6 carbon atoms, the temperature of said etchant being in a range from 20° C. to 30° C. at prescribed portions of said semicured prepolymer layer, so as to etch said prescribed portions of said semicured prepolymer layer and to expose surfaces of the first metal layer; curing said semicured prepolymer so as to form a layer of cured polymer resin; forming a second metal layer on said cured polymer resin layer and exposed surfaces of said first metal layer; and etching said second metal layer so as to form a prescribed pattern.
Claim 52
Independent Claim
187 words
A method for fabricating a semiconductor device comprising the steps of: forming a first metal layer on an insulating layer; etching said metal layer so as to form a prescribed pattern; forming a layer of semicured prepolymer resin selected from the group consisting of polyimide and polyimideiso-indroquinazolinedione and semicured at 200°-250° C., on the surface of said prescribed pattern and on exposed surfaces of said insulating layer; contacting an etchant consisting essentially of hydrazine or hydrazine hydrate and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2, wherein R is selected from divalent radicals having 2-6 carbon atoms, the temperature of said etchant being in a range from 20° C. to 30° C. at prescribed portions of said semicured prepolymer layer, so as to etch said prescribed portions of said semicured prepolymer layer and to expose surfaces of the first metal layer; curing said semicured prepolymer so as to form a layer of cured polymer resin; forming a second metal layer on said cured polymer resin layer and exposed surfaces of said first metal layer; and etching said second metal layer so as to form a prescribed pattern.
Claim 53
Dependent Claim
25 words
A method for fabricating a semiconductor device according to claim 44, wherein said semicured prepolymer is cured at a temperature higher than about 250° C.
Claim 54
Dependent Claim
27 words
A method for fabricating a semiconductor device according to claim 45, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 55
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 46, wherein the volume % of said polyamine in said etchant is between 50 and 90%.
Claim 56
Dependent Claim
23 words
A method for fabricating a semiconductor device according to claim 47, wherein the volume % of said polyamine is between 60 and 85%.
Claim 57
Dependent Claim
16 words
A method for fabricating a semiconductor device according to claim 45, wherein said polyamine is ethylenediamine.
Claim 58
Dependent Claim
26 words
A method for fabricating a semiconductor device according to claim 49, wherein the volume % of said ethylenediamine in said etchant is between 50 and 90%.
Claim 59
Dependent Claim
23 words
A method for fabricating a semiconductor device according to claim 50, wherein the volume % of said methylenediamine is between 60 and 85%.
Claim 60
Dependent Claim
48 words
An etchant for a polymer resin selected from the group consisting of polyimide and polyimide-isoindroquinazolinedione and semicured at 200°-250° C., consisting essentially of hydrazine and at least one of polyamines shown by a chemical formula of NH.sub.2.R.NH.sub.2 wherein R is selected from divalent radicals having 2-6 carbon atoms.
Claim 61
Dependent Claim
48 words
An etchant for a polymer resin selected from the group consisting of polyimide and polyimide-isoindroquinazolinedione and semicured at 200°-250° C., consisting essentially of hydrazine and at least one of polyamines shown by a chemical formula of NH.sub.2.R.NH.sub.2 wherein R is selected from divalent radicals having 2-6 carbon atoms.
Claim 62
Dependent Claim
22 words
An etchant according to claim 52, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 63
Dependent Claim
18 words
An etchant according to claim 53, wherein the volume % of said polyamine is between 50 and 90%.
Claim 64
Dependent Claim
18 words
An etchant according to claim 54, wherein the volume % of said polyamine is between 60 and 85%.
Claim 65
Dependent Claim
11 words
An etchant according to claim 53, wherein said polyamine is ethylenediamine.
Claim 66
Dependent Claim
18 words
An etchant according to claim 56, wherein the volume % of said ethylenediamine is between 50 and 90%.
Claim 67
Dependent Claim
18 words
An etchant according to claim 57, wherein the volume % of said ethylenediamine is between 60 and 85%.
Claim 68
Dependent Claim
45 words
An etchant for a polymer resin selected from the group consisting of polyimide and polyimide-isoindroquinazolinedione and semicured at 200°-250° C., consisting essentially of hydrazine and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2 wherein R is selected from the divalent radicals having 2-6 carbon atoms.
Claim 69
Dependent Claim
45 words
An etchant for a polymer resin selected from the group consisting of polyimide and polyimide-isoindroquinazolinedione and semicured at 200°-250° C., consisting essentially of hydrazine and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2 wherein R is selected from the divalent radicals having 2-6 carbon atoms.
Claim 70
Dependent Claim
22 words
An etchant according to claim 59, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 71
Dependent Claim
18 words
An etchant according to claim 60, wherein the volume % of said polyamine is between 50 and 90%.
Claim 72
Dependent Claim
18 words
An etchant according to claim 61, wherein the volume % of said polyamine is between 60 and 85%.
Claim 73
Dependent Claim
11 words
An etchant according to claim 60, wherein said polyamine is ethylenediamine.
Claim 74
Dependent Claim
18 words
An etchant according to claim 63, wherein the volume % of said ethylenediamine is between 50 and 90%.
Claim 75
Dependent Claim
18 words
An etchant according to claim 64, wherein the volume % of said ethylenediamine is between 60 and 85%.
Claim 76
Dependent Claim
66 words
An etchant for a polymer resin selected from the group consisting of polyimide and polyimide-iso-indroquinazolinedione and semicured at 200°-250° C., consisting essentially of an aqueous solution of hydrazine hydrate and at least one of polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2, wherein R is selected from divalent radicals having 2-6 carbon atoms containing more than 60 volume % of hydrazine hydrate and polyamine, balance water.
Claim 77
Dependent Claim
66 words
An etchant for a polymer resin selected from the group consisting of polyimide and polyimide-iso-indroquinazolinedione and semicured at 200°-250° C., consisting essentially of an aqueous solution of hydrazine hydrate and at least one of polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2, wherein R is selected from divalent radicals having 2-6 carbon atoms containing more than 60 volume % of hydrazine hydrate and polyamine, balance water.
Claim 78
Dependent Claim
62 words
An etchant for a polymer resin selected from the group consisting of polyimide and polyimide-iso-indroquinazolinedione and semicured at 200°-250° C., consisting essentially of an aqueous solution of hydrazine hydrate and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2 wherein R is selected from divalent radicals having 2-6 carbon atoms containing more than 60 volume % of hydrazine hydrate and polyamine, balance water.
Claim 79
Dependent Claim
62 words
An etchant for a polymer resin selected from the group consisting of polyimide and polyimide-iso-indroquinazolinedione and semicured at 200°-250° C., consisting essentially of an aqueous solution of hydrazine hydrate and polyamine shown by a chemical formula of NH.sub.2.R.NH.sub.2 wherein R is selected from divalent radicals having 2-6 carbon atoms containing more than 60 volume % of hydrazine hydrate and polyamine, balance water.
Claim 80
Dependent Claim
22 words
An etchant according to claim 67, wherein said polyamine is selected from the group consisting of ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine and hexamethylenediamine.
Claim 81
Dependent Claim
18 words
An etchant according to claim 68, wherein the volume % of said polyamine is between 50 and 90%.
Claim 82
Dependent Claim
18 words
An etchant according to claim 69, wherein the volume % of said polyamine is between 60 and 85%.
Claim 83
Dependent Claim
11 words
An etchant according to claim 68, wherein said polyamine is ethylenediamine.
Claim 84
Dependent Claim
18 words
An etchant according to claim 71, wherein the volume % of said ethylenediamine is between 50 and 90%.
Claim 85
Dependent Claim
18 words
An etchant according to claim 72, wherein the volume % of said ethylenediamine is between 60 and 85%.
References Cited (Backward Citations)
US3395057A
Cited
US3700497A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-11 | 1982-03-13 | 1982-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-11 | 1986-03-13 | 1986-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-11 | 1990-03-13 | 1990-09-12 | $7700.00 | Window Closed / Lapsed |