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Method of making stacked textured container capacitor

Assignee: Micron Technology Inc
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Filing: 1991-01-22
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Granted: 1992-01-21
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Expires: 2011-01-22
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Abstract

Abstract A stacked textured container capacitor (STCC) using a modified stacked capacitor storage cell fabrication process. The STCC is made up of a texturized polysilicon structure, having an elongated u-shaped cross-section, located at a buried contact and extending to an adjacent storage node overlaid by polysilicon with a dielectric sandwiched in between. With the 3-dimensional shape and texturized surface of a polysilicon storage node plate substantial capacitor plate surface area of 200% or more is gained at the storage node.

Inventors

  • 👤 Hiang C. Chan
  • 👤 Pierre Fazan
  • 👤 Yauh-Ching Liu

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 10:46
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10B12/30; H10B12/31; H10B12/318; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10D1/711; H10D1/712; H10D1/716

Claims Analysis

Total Claims: 16
Claim 1
Independent Claim 528 words
A process for fabricating a DRAM array on a silicon substrate, said process comprising the following sequence of steps: creating a plurality of separately isolated active areas arranged in parallel interdigitated rows and parallel non-interdigitated columns; creating a gate dielectric layer on top of each active area; depositing a first conductive layer superjacent surface of said array; depositing a first dielectric layer superjacent said first conductive layer; masking and etching said first conductive and said first dielectric layers to form a plurality of parallel conductive word lines aligned along said rows such that each said word line passes over a inner portion of each said active area being separated therefrom by a remanent of said gate dielectric layer; creating of a conductively-doped digit line junction and storage node junction within each said active area on opposite sides of each said word line; depositing a second dielectric layer superjacent said array surface; creating a first aligned buried contact location at each said digit line junction in each said active area; depositing a second conductive layer superjacent said array surface, said second conductive layer making direct contact to said digit line junctions at said first buried contact locations; depositing a third dielectric layer superjacent to said second conductive layer; masking and etching said second conductive layer and said third dielectric layer to form a plurality of parallel conductive digit lines aligned along said columns such that a digit line makes electrical contact at each digit line junction within a column, said digit lines running perpendicular to and over said word lines forming a 3-dimensional, waveform-like topology; depositing a first nitride layer superjacent said array surface of said waveform-like topology; creating a second aligned buried contact location at each said storage node junction in each said active area; depositing a third conductive layer superjacent said array surface assuming said waveform-like topology in response to existing topology, said third conductive layer making contact to said storage node junctions at said second buried contact locations; depositing a second nitride layer; patterning said third conductive layer and said second nitride layer to form a portion of a poly storage node plate at each said storage node junction, said poly storage node plate having a u-shaped cross-section; depositing a third nitride layer; etching said third nitride layer thereby forming vertical nitride spacers superjacent to vertical sides of said poly storage node plate and said second dielectric; depositing a first oxide layer; planarizing said first oxide layer thereby forming oxide fillers between said vertical nitride spacers; etching said first nitride layer and said nitride spacers; depositing a fourth conductive layer adjacent and coextensive with existing topology; etching said fourth conductive layer thereby forming vertical poly spacer walls adjacent to said oxide fillers, said spacer walls attaching to said third conductive layer thereby forming a poly storage node plate having an elongated u-shaped cross-section; etching said oxide fillers; texturizing said poly storage node plate; depositing a cell dielectric layer adjacent and coextensive with said storage node plate and adjacent said array surface; and depositing a fifth conductive layer adjacent and coextensive with said cell dielectric layer to form a cell plate common to the entire memory array.
Claim 2
Dependent Claim 528 words
A process for fabricating a DRAM array on a silicon substrate, said process comprising the following sequence of steps: creating a plurality of separately isolated active areas arranged in parallel interdigitated rows and parallel non-interdigitated columns; creating a gate dielectric layer on top of each active area; depositing a first conductive layer superjacent surface of said array; depositing a first dielectric layer superjacent said first conductive layer; masking and etching said first conductive and said first dielectric layers to form a plurality of parallel conductive word lines aligned along said rows such that each said word line passes over a inner portion of each said active area being separated therefrom by a remanent of said gate dielectric layer; creating of a conductively-doped digit line junction and storage node junction within each said active area on opposite sides of each said word line; depositing a second dielectric layer superjacent said array surface; creating a first aligned buried contact location at each said digit line junction in each said active area; depositing a second conductive layer superjacent said array surface, said second conductive layer making direct contact to said digit line junctions at said first buried contact locations; depositing a third dielectric layer superjacent to said second conductive layer; masking and etching said second conductive layer and said third dielectric layer to form a plurality of parallel conductive digit lines aligned along said columns such that a digit line makes electrical contact at each digit line junction within a column, said digit lines running perpendicular to and over said word lines forming a 3-dimensional, waveform-like topology; depositing a first nitride layer superjacent said array surface of said waveform-like topology; creating a second aligned buried contact location at each said storage node junction in each said active area; depositing a third conductive layer superjacent said array surface assuming said waveform-like topology in response to existing topology, said third conductive layer making contact to said storage node junctions at said second buried contact locations; depositing a second nitride layer; patterning said third conductive layer and said second nitride layer to form a portion of a poly storage node plate at each said storage node junction, said poly storage node plate having a u-shaped cross-section; depositing a third nitride layer; etching said third nitride layer thereby forming vertical nitride spacers superjacent to vertical sides of said poly storage node plate and said second dielectric; depositing a first oxide layer; planarizing said first oxide layer thereby forming oxide fillers between said vertical nitride spacers; etching said first nitride layer and said nitride spacers; depositing a fourth conductive layer adjacent and coextensive with existing topology; etching said fourth conductive layer thereby forming vertical poly spacer walls adjacent to said oxide fillers, said spacer walls attaching to said third conductive layer thereby forming a poly storage node plate having an elongated u-shaped cross-section; etching said oxide fillers; texturizing said poly storage node plate; depositing a cell dielectric layer adjacent and coextensive with said storage node plate and adjacent said array surface; and depositing a fifth conductive layer adjacent and coextensive with said cell dielectric layer to form a cell plate common to the entire memory array.
Claim 3
Dependent Claim 14 words
A process as recited in claim 1, wherein said gate dielectric layer is oxide.
Claim 4
Dependent Claim 24 words
A process as recited in claim 1, wherein said first and said second conductive layers comprise a layer of tungsten silicide and doped polysilicon.
Claim 5
Dependent Claim 28 words
A process as recited in claim 1, wherein said first, said second and said fourth dielectric layers are selected from the group consisting essentially of oxide or nitride.
Claim 6
Dependent Claim 18 words
A process as recited in claim 1, wherein said first and said second buried contacts are self aligned.
Claim 7
Dependent Claim 20 words
A process as recited in claim 1, wherein said third, said fourth and said fifth conductive layers are doped polysilicon.
Claim 8
Dependent Claim 23 words
A process as recited in claim 1, wherein said first, said second, and said third dielectric layers are deposited by chemical vapor deposition.
Claim 9
Dependent Claim 18 words
A process as recited in claim 1, wherein said first nitride layer is deposited by chemical vapor deposition.
Claim 10
Dependent Claim 22 words
A process as recited in claim 1, wherein said first nitride layer is deposited to a thickness of 2000 to 6000 angstroms.
Claim 11
Dependent Claim 25 words
A process as recited in claim 1, wherein said etching of third nitride layer to form said vertical spacers is accomplished by an anisotropic etch.
Claim 12
Dependent Claim 27 words
A process as recited in claim 1, wherein said etching of first nitride layer and said vertical nitride spacers is accomplished by a controlled wet nitride etch.
Claim 13
Dependent Claim 27 words
A process as recited in claim 1, wherein said etching of fourth conductive layer to form said vertical poly spacer walls is accomplished by an anisotropic etc.
Claim 14
Dependent Claim 39 words
A process as recited in claim 1, wherein said texturizing comprises the steps of: a) subjecting said poly storage node plate to wet oxidation; and b) performing an oxide wet etch thereby forming said texturized poly storage node plate.
Claim 15
Dependent Claim 19 words
A process as recited in claim 1, wherein said cell dielectric layer is material having a high dielectric constant.
Claim 16
Dependent Claim 26 words
A process as recited in claim 14, wherein said layer cell dielectric material is selected from the group consisting essentially of nitride, oxidized nitride and Ta2O5.

References Cited (Backward Citations)

JPS63278363A Cited
JPS6442161A Cited
JPH0264251A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1995-01-20 1995-07-22 1996-01-21 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1999-01-20 1999-07-22 2000-01-21 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2003-01-20 2003-07-22 2004-01-21 $7700.00 Window Closed / Lapsed

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