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US6423474B1 Expired / Lapsed US ⏱️ 0.0 years remaining

Use of DARC and BARC in flash memory processing

Assignee: Micron Technology Inc
•
Filing: 2000-03-21
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Granted: 2002-07-23
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Expires: 2020-03-21
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Abstract

Abstract A method of using dielectric anti-reflective coating (DARC) in conjunction with bottom anti-reflective coating (BARC) to form an anti-reflective barrier layer is provided. The anti-reflective layer conforms to the topography of the substrate surface and is adapted to function effectively in both annealed and unannealed states. The method of using DARC in combination with BARC also inhibits the nitride layer of a gate stack to seep into adjacent photoresist layers and adversely affect the composition of the photoresist.

Inventors

  • 👤 Richard D. Holscher

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 08:43
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/09; G03F7/091; H; H10; H10P; H10P76/00; H10P76/20; H10P76/204; H10P76/2041; H10P76/2043; G03F7/0035; Y; Y10; Y10S; Y10S430/00; Y10S430/151

Claims Analysis

Total Claims: 33
Claim 1
Independent Claim 185 words
A method of patterning and etching a semiconductor surface, the method comprising: forming an anti-reflective barrier on the semiconductor surface that has a first component tuned to absorb reflected light from the semiconductor surface in an unannealed state and a second component tuned to absorb reflected light from the semiconductor surface in an annealed state; positioning a first photoresist layer on the anti-reflective barrier; patterning and etching the first photoresist layer wherein the first component of the anti-reflective barrier inhibit light from being reflected from the semiconductor surface into the first photoresist layer during patterning and etching of the first photoresist layer; annealing the semiconductor surface following the patterning and etching of the first photoresist layer wherein the annealing step improves the ability of the second component of the anti-reflective barrier to inhibit reflected light to pass therethrough; depositing a second photoresist layer on the anti-reflective barrier; patterning and etching the second photoresist layer wherein the second component of the anti-reflection barrier inhibits light from being reflected from the semiconductor surface into the second photoresist layer during patterning and etching of the second photoresist layer.
Claim 2
Independent Claim 185 words
A method of patterning and etching a semiconductor surface, the method comprising: forming an anti-reflective barrier on the semiconductor surface that has a first component tuned to absorb reflected light from the semiconductor surface in an unannealed state and a second component tuned to absorb reflected light from the semiconductor surface in an annealed state; positioning a first photoresist layer on the anti-reflective barrier; patterning and etching the first photoresist layer wherein the first component of the anti-reflective barrier inhibit light from being reflected from the semiconductor surface into the first photoresist layer during patterning and etching of the first photoresist layer; annealing the semiconductor surface following the patterning and etching of the first photoresist layer wherein the annealing step improves the ability of the second component of the anti-reflective barrier to inhibit reflected light to pass therethrough; depositing a second photoresist layer on the anti-reflective barrier; patterning and etching the second photoresist layer wherein the second component of the anti-reflection barrier inhibits light from being reflected from the semiconductor surface into the second photoresist layer during patterning and etching of the second photoresist layer.
Claim 3
Dependent Claim 58 words
The method of claim 1 , wherein forming an anti-reflection barrier comprises: positioning a layer of DARC material on the semiconductor surface such that the DARC comprises the second component of the anti-reflection barrier; and positioning a layer of BARC on the layer of DARC material such that the BARC comprises the first component of the anti-reflection barrier.
Claim 4
Dependent Claim 19 words
The method of claim 2 , further comprising removing the BARC following patterning and etching the first photoresist layer.
Claim 5
Dependent Claim 15 words
The method of claim 3 , wherein removing the BARC comprises a dry plasma process.
Claim 6
Dependent Claim 32 words
The method of claim 2 , wherein positioning the layer of DARC comprises positioning a layer of DARC material formulated with a refractive index of 1.95 and an extinction coefficient of 0.53.
Claim 7
Dependent Claim 33 words
The method of claim 2 , wherein forming the anti-reflective barrier on the semiconductor surface comprises forming an anti-reflective barrier on a nitride layer wherein the nitride layer is approximately 250 Angstroms thick.
Claim 8
Dependent Claim 24 words
The method of claim 2 , wherein positioning the layer of BARC comprises positioning a layer of BARC that is approximately 620 Angstroms thick.
Claim 9
Dependent Claim 37 words
The method of claim 2 , wherein positioning the layer of DARC comprises positioning a layer of DARC formulated with a refractive index of 1.95 and an extinction coefficient of 0.53 that is approximately 475 Angstroms thick.
Claim 10
Dependent Claim 24 words
The method of claim 2 , wherein positioning the layer of DARC comprises forming a layer of DARC that conforms to the semiconductor surface.
Claim 11
Dependent Claim 24 words
The method of claim 9 , wherein positioning the layer of DARC comprises forming a layer of DARC using a chemical vapor deposition process.
Claim 12
Dependent Claim 29 words
The method of claim 2 , wherein positioning the layer of BARC comprises forming a layer of BARC on a generally planar surface provided by the layer of DARC.
Claim 13
Dependent Claim 23 words
The method of claim 2 , wherein positioning the layer of BARC comprises forming a layer of BARC using a spin coating process.
Claim 14
Dependent Claim 57 words
The method of claim 1 , wherein forming the anti-reflective barrier comprises Conning an anti-reflective layer having a light reflectivity of between approximately 0.02 and 0.03, wherein the light reflectivity is the fraction of light reflected from the semiconductor surface in relation to the amount of light projected onto the semiconductor surface, following annealing the semiconductor surface.
Claim 15
Independent Claim 189 words
A method of inhibiting light from reflecting off of an exposed surface of a semiconductor device during patterning and etching, the method comprising: positioning a first barrier layer on the exposed surface semiconductor device wherein the first barrier layer is configured to inhibit light reflecting from the exposed surface of the semiconductor device from traveling therethrough; positioning a second barrier layer on the first barrier layer wherein the second barrier layer is configured to inhibit light reflecting from the exposed surface of the semiconductor device from traveling therethrough before annealing; positioning a first photoresist layer on the second barrier layer; patterning and etching the first photoresist layer wherein the second barrier layer decreases the amount of reflected light reflecting from the exposed surface from entering the first photoresist layer during patterning and etching of the first photoresist layer; transforming the first barrier layer by annealing the semiconductor device so as to improve the ability of the first barrier layer to prevent light from being reflected from the exposed surface of the semiconductor device into a subsequently deposited photoresist layer during patterning and etching of the subsequently deposited photoresist layer.
Claim 16
Independent Claim 189 words
A method of inhibiting light from reflecting off of an exposed surface of a semiconductor device during patterning and etching, the method comprising: positioning a first barrier layer on the exposed surface semiconductor device wherein the first barrier layer is configured to inhibit light reflecting from the exposed surface of the semiconductor device from traveling therethrough; positioning a second barrier layer on the first barrier layer wherein the second barrier layer is configured to inhibit light reflecting from the exposed surface of the semiconductor device from traveling therethrough before annealing; positioning a first photoresist layer on the second barrier layer; patterning and etching the first photoresist layer wherein the second barrier layer decreases the amount of reflected light reflecting from the exposed surface from entering the first photoresist layer during patterning and etching of the first photoresist layer; transforming the first barrier layer by annealing the semiconductor device so as to improve the ability of the first barrier layer to prevent light from being reflected from the exposed surface of the semiconductor device into a subsequently deposited photoresist layer during patterning and etching of the subsequently deposited photoresist layer.
Claim 17
Dependent Claim 18 words
The method of claim 14 , wherein positioning the first barrier layer comprises positioning a layer of DARC.
Claim 18
Dependent Claim 24 words
The method of claim 15 , wherein positioning the layer of DARC comprises positioning a layer of DARC that is approximately 475 Angstroms thick.
Claim 19
Dependent Claim 24 words
The method of claim 16 , wherein positioning the second barrier layer comprises positioning a layer of BARC that is approximately 620 Angstroms thick.
Claim 20
Dependent Claim 18 words
The method of claim 14 , wherein positioning the second barrier layer comprises positioning a layer of BARC.
Claim 21
Dependent Claim 58 words
The method of claim 14 , wherein transforming the first barrier layer by annealing the semiconductor device comprises transforming the light reflectivity of a layer of DARC to approximately 0.02 to 0.03, wherein the light reflectivity is the fraction of light reflected from the semiconductor device in relation to the amount of light projected onto the semiconductor device.
Claim 22
Dependent Claim 26 words
The method of claim 14 , wherein positioning the first barrier layer on the exposed surface comprises positioning a layer of DARC on a nitride surface.
Claim 23
Independent Claim 78 words
A method of forming an anti-reflective barrier layer on a semiconductive device, the method comprising: forming a DARC layer that functions as an anti-reflective coating in an annealed state on a first surface of the device wherein the DARC layer substantially conforms to the topography of the first surface and has a substantially flat upper surface; forming a BARC layer that functions as an anti-reflective coating in an unannealed state on the upper surface of the DARC layer.
Claim 24
Independent Claim 78 words
A method of forming an anti-reflective barrier layer on a semiconductive device, the method comprising: forming a DARC layer that functions as an anti-reflective coating in an annealed state on a first surface of the device wherein the DARC layer substantially conforms to the topography of the first surface and has a substantially flat upper surface; forming a BARC layer that functions as an anti-reflective coating in an unannealed state on the upper surface of the DARC layer.
Claim 25
Dependent Claim 108 words
The method of claim 21 further comprising: forming a first layer of photoresist on an upper surface of the BARC layer; exposing the first layer of photoresist in a first photo imaging operation wherein the BARC layer is used to inhibit reflected light waves from traversing back through into the first layer of photoresist; removing the layer of BARC; annealing the substrate; forming a second layer of photoresist on an upper surface of the DARC layer; exposing the second layer of photoresist in a second photo imaging operation wherein the DARC layer is used to inhibit reflected light waves from traversing back through the second layer of photoresist.
Claim 26
Dependent Claim 33 words
The method of claim 22 , wherein forming the DARC layer on a semiconductive device comprises forming the DARC layer on a first surface of a gate stack of a FLASH memory circuit.
Claim 27
Dependent Claim 24 words
The method of claim 21 , wherein forming the DARC layer on a first surface comprises forming the DARC layer on a nitride layer.
Claim 28
Independent Claim 136 words
A method of forming a FLASH memory circuit, the method comprising: forming a gate stack on a substrate surface; forming a layer of DARC that functions as an anti-reflective coating in an annealed state onto an upper surface of the gate stack; forming a layer of BARC that functions as an anti-reflective coating in an unannealed state onto an upper surface of the DARC layer; forming a first layer of photoresist on the upper surface of the BARC layer; exposing the first layer of photoresist in a first print and etch operation; removing the layer of BARC from the upper surface of the DARC layer; annealing the gate stack; forming a second layer of photoresist on the upper surface of the DARC layer; exposing the second layer of photoresist in a second print and etch operation.
Claim 29
Independent Claim 136 words
A method of forming a FLASH memory circuit, the method comprising: forming a gate stack on a substrate surface; forming a layer of DARC that functions as an anti-reflective coating in an annealed state onto an upper surface of the gate stack; forming a layer of BARC that functions as an anti-reflective coating in an unannealed state onto an upper surface of the DARC layer; forming a first layer of photoresist on the upper surface of the BARC layer; exposing the first layer of photoresist in a first print and etch operation; removing the layer of BARC from the upper surface of the DARC layer; annealing the gate stack; forming a second layer of photoresist on the upper surface of the DARC layer; exposing the second layer of photoresist in a second print and etch operation.
Claim 30
Dependent Claim 21 words
The method of claim 25 , wherein removing the BARC layer comprises substantially removing the BARC using a wet clean process.
Claim 31
Dependent Claim 30 words
The method of claim 25 , wherein forming the layer of DARC onto the upper surface of the gate stack comprises forming the layer of DARC onto a nitride layer.
Claim 32
Dependent Claim 18 words
The method of claim 25 , wherein annealing the gate stack reduces the reflectivity of the DARC layer.
Claim 33
Dependent Claim 31 words
The method of claim 25 , wherein forming the layer of DARC comprising forming a layer of DARC formulated with a refractive index of 1.95 and an extinction coefficient of 0.53.

References Cited (Backward Citations)

JPH09222726A Cited
US5986318A Cited
US5994217A Cited
US5990002A Cited
US6169029B1 Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2005-07-22 2006-01-21 2006-07-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2009-07-22 2010-01-21 2010-07-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2013-07-22 2014-01-21 2014-07-23 $7700.00 Window Closed / Lapsed

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