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US5071783A
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Method of producing a dynamic random access memory device
Assignee: Fujitsu Ltd
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Filing: 1989-07-05
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Granted: 1991-12-10
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Expires: 2009-07-05
Abstract
Abstract A dynamic random access memory device includes a storage capacitor having a plurality of stacked conductive films which form a storage electrode. A gap is formed between elevationally adjacent conductive films so as to surround the storage electrode. A gap is also formed between an insulating film which covers a gate electrode for insulation and a lowermost film of the storage electrode. Connection between the adjacent films may be established so that an uppermost film elevationally extends so as to make contact with a drain region. Also, connection can be established so that an upper film is mounted directly on a lower film. An end portion of the film may be thicker than the other portion thereof. The stacked film structure may be produced by alternatively forming a film made of a material different from the insulating film covering the gate electrode, and a conductive film.
Inventors
- 👤 Masao Taguchi
- 👤 Taiji Ema
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:05
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10B12/30; H10B12/31; H10B12/318; H10D; H10D1/00; H10D1/01; H10D1/041; H10D1/042; H10D1/60; H10D1/68; H10D1/692; H10D1/711; H10D1/714
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
223 words
A method of procducing a dynamic random access memory device comprising the steps of: forming a transer transistor comprising a pair of impurity diffucsed regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a first conductive flm on the first film; forming a second film on the first condcutive film, the second film being made of a material different from the first film; forming an opening which penetrates the first film, the first conductive film and the second film, so that either one of the impurity diffused regions is exposed through the opening; forming a second conductive film on the exposed impurity diffused region, on inner wall of the opening and the exposed second film; patterning the first and second conductive films and the second film in accordance with a desired size of a storage electrode; selectively removing a remaining portion of the second film by isotropic etching; forming a dielectric film on an exposed surface of the patterned first and second conductive films; and forming a third conductive film so as to surround the patterned first and second conductive films around which the dielectric film is formed.
Claim 2
Independent Claim
223 words
A method of procducing a dynamic random access memory device comprising the steps of: forming a transer transistor comprising a pair of impurity diffucsed regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a first conductive flm on the first film; forming a second film on the first condcutive film, the second film being made of a material different from the first film; forming an opening which penetrates the first film, the first conductive film and the second film, so that either one of the impurity diffused regions is exposed through the opening; forming a second conductive film on the exposed impurity diffused region, on inner wall of the opening and the exposed second film; patterning the first and second conductive films and the second film in accordance with a desired size of a storage electrode; selectively removing a remaining portion of the second film by isotropic etching; forming a dielectric film on an exposed surface of the patterned first and second conductive films; and forming a third conductive film so as to surround the patterned first and second conductive films around which the dielectric film is formed.
Claim 3
Dependent Claim
86 words
A method of producing a dynamic random access memory device as claimed in claim 1, further comprising the step, between the step of forming the first film and the step of forming the first conductive film, of forming a third film on the first film, so that the first conductive film is formed on the third film, the third film being made of a material different from the first film, the third film being selectively removed together with the second film at the isotropic etching process.
Claim 4
Dependent Claim
45 words
A method of producing a dynamic random access memory device as claimed in claim 1, wherein the step of forming the first conductive film and the step of forming the second film are repetitively performed, and thereafter the step of forming the opening is performed.
Claim 5
Dependent Claim
28 words
A method of producing a dynamic random access memory device as claimed in claim 1, wherein the the first conductive film is formed directly on the first film.
Claim 6
Dependent Claim
33 words
A method of producing a dynamic random access memory device as claimed in claim 1, wherein in the patterning step, the first and second conductive films are patterned by the same resist film.
Claim 7
Dependent Claim
32 words
A method of producing a dynamic random access memory device as claimed in claim 1, wherein in the patterning step, the first and second conductive films are patterned by different resist films.
Claim 8
Independent Claim
236 words
A method of producing a dynamic random access memory device comprising the steps of: forming a transfer transistor comprising a pair of impurity diffused regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a first opening in the first film, either one of the impurity diffused regions being exposed through the opening; forming a first conductive film on the first film and in the first opening; forming a second film on the first conductive film, the second film being made of a material different from the first film; forming a second opening in the second film above said one of the impurity diffused regions, the first conductive film being exposed through the opening; forming a second conductive film on the first conductive film and in the second opening; patterning the first and second conductive films and the second film in accordance with a desired size of a storage electrode; selectively removing a remaining portion of the second film by isotropic etching; forming a dielectric film on an exposed surface of the patterned first and second conductive films; and forming a third conductive film so as to surround the patterned first and second conductive films around which the dielectric film is formed.
Claim 9
Independent Claim
236 words
A method of producing a dynamic random access memory device comprising the steps of: forming a transfer transistor comprising a pair of impurity diffused regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a first opening in the first film, either one of the impurity diffused regions being exposed through the opening; forming a first conductive film on the first film and in the first opening; forming a second film on the first conductive film, the second film being made of a material different from the first film; forming a second opening in the second film above said one of the impurity diffused regions, the first conductive film being exposed through the opening; forming a second conductive film on the first conductive film and in the second opening; patterning the first and second conductive films and the second film in accordance with a desired size of a storage electrode; selectively removing a remaining portion of the second film by isotropic etching; forming a dielectric film on an exposed surface of the patterned first and second conductive films; and forming a third conductive film so as to surround the patterned first and second conductive films around which the dielectric film is formed.
Claim 10
Dependent Claim
110 words
A method of producing a dynamic random access memory device as claimed in claim 7, further comprising the step, between the step of forming the first film and the step of forming the first conductive film, of forming a third film on the first film, the third film being made of a material different from the first film, wherein the first conductive film is formed on the third film, and the first opening is formed so as to penetrate the first and third film at the step of forming the first opening, and wherein the third film is selectively removed together with the second film at the isotropic etching process.
Claim 11
Dependent Claim
42 words
A method of producing a dynamic random access memory device as claimed in claim 7, wherein the step of forming the second film the step of forming the second opening, and the step of forming the second conductive film are repetitively performed.
Claim 12
Dependent Claim
28 words
A method of producing a dynamic random access memory device as claimed in claim 7, wherein the the first conductive film is formed directly on the first film.
Claim 13
Dependent Claim
33 words
A method of producing a dynamic random access memory device as claimed in claim 7, wherein in the patterning step, the first and second conductive films are patterned by the same resist film.
Claim 14
Dependent Claim
32 words
A method of producing a dynamic random access memory device as claimed in claim 7, wherein in the patterning step, the first and second conductive films are patterned by different resist films.
Claim 15
Independent Claim
248 words
A method of producing a dynamic random access memory device comprising the steps of: forming a transfer transistor comprising a pair of impurity diffused regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a second film on the first film, the second film being made of a material different from the first film; forming a first conductive film on the second film; forming a first opening wider than one of the impurity diffused regions in the first conductive film and a second opening in the first and and second films, either one of the first and second the impurity diffused regions being exposed through the first opening; depositing a second conductive film on the first conductive film, the second film and in the second opening; patterning the first and second conductive films in accordance with a desired size of a storage electrode, so that a storage electrode having a stepped part on an end thereof is formed by the patterned first and second conductive films; selectively removing the second film by isotropic etching; forming a dielectric film on an exposed surface of the patterned first and second conductive films; and forming a third conductive film so as to surround the patterned first and second conductive films around which the dielectric film is formed.
Claim 16
Independent Claim
248 words
A method of producing a dynamic random access memory device comprising the steps of: forming a transfer transistor comprising a pair of impurity diffused regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a second film on the first film, the second film being made of a material different from the first film; forming a first conductive film on the second film; forming a first opening wider than one of the impurity diffused regions in the first conductive film and a second opening in the first and and second films, either one of the first and second the impurity diffused regions being exposed through the first opening; depositing a second conductive film on the first conductive film, the second film and in the second opening; patterning the first and second conductive films in accordance with a desired size of a storage electrode, so that a storage electrode having a stepped part on an end thereof is formed by the patterned first and second conductive films; selectively removing the second film by isotropic etching; forming a dielectric film on an exposed surface of the patterned first and second conductive films; and forming a third conductive film so as to surround the patterned first and second conductive films around which the dielectric film is formed.
Claim 17
Dependent Claim
60 words
A method of producing a dynamic random access memory device as claimed in claim 13, wherein the first film is a silicon nitride film and the second film is a silicon dioxide film, and wherein the first, second and third conductive films are polysilicon films, and wherein isotropic etching at the selectively removing step uses a liquid containing hydrogen fluoride.
Claim 18
Dependent Claim
65 words
A method of producing a dynamic random access memory device as claimed in claim 13, wherein the first film is a silicon dioxide film and the second film is a silicon nitride film, and wherein the first, second and third conductive films are polysilicon films, and wherein isotropic etching at the selectively removing step uses a liquid containing phosphoric acid (PH 3 PO 4 ).
Claim 19
Independent Claim
256 words
A method of producing a dynamic random access memory device comprising the steps of: forming a transfer transistor comprising a pair of impurity diffused regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a first conductive film on the first film and the first film; forming an opening in the first conductive film; forming a second conductive film on the first conductive film and the first film; forming a second film on the second conductive film, the second film being made of a material different from the first film; forming a second opening which penetrates the first film, the second conductive film and the second film, so that either one of the impurity diffused regions is exposed through the second opening; forming a third conductive film on the second film, an inner wall of the second opening and the exposed impurity diffused region; patterning the first, second and third conductive films and the second film in accordance with a desired size of a storage electrode; selectively removing a remaining portion of the second film 132a 2 by isotropic etching; forming a dielectric film on an exposed surface of the patterned first, second and third conductive films; and forming a fourth conductive film so as to surround the patterned first, second and third conductive films around which the dielectric film is formed.
Claim 20
Independent Claim
256 words
A method of producing a dynamic random access memory device comprising the steps of: forming a transfer transistor comprising a pair of impurity diffused regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a first conductive film on the first film and the first film; forming an opening in the first conductive film; forming a second conductive film on the first conductive film and the first film; forming a second film on the second conductive film, the second film being made of a material different from the first film; forming a second opening which penetrates the first film, the second conductive film and the second film, so that either one of the impurity diffused regions is exposed through the second opening; forming a third conductive film on the second film, an inner wall of the second opening and the exposed impurity diffused region; patterning the first, second and third conductive films and the second film in accordance with a desired size of a storage electrode; selectively removing a remaining portion of the second film 132a 2 by isotropic etching; forming a dielectric film on an exposed surface of the patterned first, second and third conductive films; and forming a fourth conductive film so as to surround the patterned first, second and third conductive films around which the dielectric film is formed.
Claim 21
Dependent Claim
73 words
A method of producing a dynamic random access memory device as claimed in claim 16, further comprising the step, between the step of forming the first film and the step of forming the first conductive film, of forming a third film on the first film so that the first conductive film is formed on the third film, the third film being selectively removed together with the second film at the isotropic etching process.
Claim 22
Dependent Claim
46 words
A method of producing a dynamic random access memory device as claimed in claim 16, wherein the step of forming the second conductive film and the step of forming the second film are repetitively performed, and thereafter the step of forming the second opening is performed.
Claim 23
Dependent Claim
28 words
A method of producing a dynamic random access memory device as claimed in claim 16, wherein the the first conductive film is formed directly on the first film.
Claim 24
Dependent Claim
34 words
A method of producing a dynamic random access memory device as claimed in claim 16, wherein in the patterning step, the first, second and third conductive films are patterned by the same resist film.
Claim 25
Dependent Claim
40 words
A method of producing a dynamic random access memory device as claimed in claim 16, wherein in the patterning step, the first and second conductive films are patterned by a resist film different from that for the third conductive film.
Claim 26
Independent Claim
261 words
A method of producing a dynamic random access memory device comprising the steps of: forming a transfer transistor comprising a pair of impurity diffused regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a first conductive film on the first film; opening a first opening wider than one of the impurity diffused regions in the first conductive film; forming a second opening in the first film, either one of the impurity diffused regions being exposed through the second opening; forming a second conductive film on the first conductive film, the first film and in the second opening; forming a second film on the second conductive film, the second film being made of a material different from the first film; forming a third opening in the second film above said one of the impurity diffused regions; forming a third conductive film on the second conductive film and in the third opening; patterning the first, second and third conductive films and the second film in accordance with a desired size of a storage electrode; selectively removing a remaining portion of the second film by isotropic etching; forming a dielectric film on an exposed surface of the patterned first, second and third conductive films; and forming a fourth conductive film so as to surround the patterned first, second and third conductive films around which the dielectric film is formed.
Claim 27
Independent Claim
261 words
A method of producing a dynamic random access memory device comprising the steps of: forming a transfer transistor comprising a pair of impurity diffused regions which are located within an area defined by a field insulating film formed on a substrate, and a gate electrode being located between the pair of impurity diffused regions; forming a first film so as to cover the transfer transistor for insulation; forming a first conductive film on the first film; opening a first opening wider than one of the impurity diffused regions in the first conductive film; forming a second opening in the first film, either one of the impurity diffused regions being exposed through the second opening; forming a second conductive film on the first conductive film, the first film and in the second opening; forming a second film on the second conductive film, the second film being made of a material different from the first film; forming a third opening in the second film above said one of the impurity diffused regions; forming a third conductive film on the second conductive film and in the third opening; patterning the first, second and third conductive films and the second film in accordance with a desired size of a storage electrode; selectively removing a remaining portion of the second film by isotropic etching; forming a dielectric film on an exposed surface of the patterned first, second and third conductive films; and forming a fourth conductive film so as to surround the patterned first, second and third conductive films around which the dielectric film is formed.
Claim 28
Dependent Claim
110 words
A method of producing a dynamic random access memory device as claimed in claim 22, further comprising the step, between the step of forming the first film and the step of forming the first conductive film, of forming a third film on the first film, the third film being made of a material different from the first film, wherein the first conductive film is formed on the third film, and the second opening is formed so as to penetrate the first and third films at the step of forming the second opening, and wherein the third film is selectively removed together with the second film at the isotropic etching process.
Claim 29
Dependent Claim
42 words
A method of producing a dynamic random access memory device as claimed in claim 23, wherein the step of forming the second film, the step of forming the second opening, and the step of forming the second conductive film are repetitively performed.
Claim 30
Dependent Claim
28 words
A method of producing a dynamic random access memory device as claimed in claim 23, wherein the the first conductive film is formed directly on the first film.
Claim 31
Dependent Claim
34 words
A method of producing a dynamic random access memory device as claimed in claim 23, wherein in the patterning step, the first, second and third conductive films are patterned by the same resist film.
Claim 32
Dependent Claim
42 words
A method of producing a dynamic random access memory device as claimed in claim 23, wherein in the patterning step, the first and second conductive films are patterned by a resist film which is different from that for the third conductive film.
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