Patent US5904575A successfully refreshed from Google Patents.
US5904575A
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Method and apparatus incorporating nitrogen selectively for differential oxide growth
Assignee: Lattice Semiconductor Corp
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Filing: 1997-02-14
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Granted: 1999-05-18
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Expires: 2017-02-14
Abstract
Abstract A method for forming an oxide on the surface of a semiconductor substrate. The method includes the steps of: placing the semiconductor substrate in an atmosphere containing an atmosphere of an oxide growth inhibiting compound; applying laser energy to at least a first portion of the substrate; and forming the oxide on the surface of the substrate by heating the substrate. In a further aspect of the invention, the method comprises applying laser energy through a patterned, reflective reticle. Alternatively, prior to the step of placing, a reflective mask layer may be applied to the surface of the semiconductor substrate. In addition, the invention comprises an EEPROM memory cell having a program junction region in a semiconductor substrate. The cell comprises at least a first program junction provided in the silicon substrate and a floating gate having a portion positioned over the program junction. In addition, an oxide layer is positioned between the program junction and the floating gate, the gate oxide formed by a single thermal oxidation step to have at least a first oxide thickness and a second oxide thickness due to gas immersion laser doped nitrogen underlying a region of the oxide having said at least first oxide thickness.
Inventors
- 👤 Emi Ishida
- 👤 Xiao-Yu Li
- 👤 Sunil D. Mehta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:12
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/65; H10P14/6502; H10P14/6509; H10B; H10B69/00; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0144; H10D84/02; H10D84/03; H10D84/038; H10P14/6512; H10P30/00; H10P30/20; H10P30/202; H10P30/204; H10P30/208; H10P30/22; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309; H10P14/6322; Y; Y10; Y10S; Y10S148/00; Y10S148/126; Y10S438/00; Y10S438/981
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
78 words
A method for forming an oxide on the surface of the semiconductor substrate, comprising: (A) placing the semiconductor substrate in an atmosphere of an oxide growth inhibiting compound; and then (B) applying laser energy and introducing the oxide growth inhibiting compound to a first portion of the semiconductor substrate and not a second portion of the semiconductor substrate; and (C) forming said oxide on both the first and second portions of the semiconductor substrate by heating the substrate.
Claim 2
Independent Claim
78 words
A method for forming an oxide on the surface of the semiconductor substrate, comprising: (A) placing the semiconductor substrate in an atmosphere of an oxide growth inhibiting compound; and then (B) applying laser energy and introducing the oxide growth inhibiting compound to a first portion of the semiconductor substrate and not a second portion of the semiconductor substrate; and (C) forming said oxide on both the first and second portions of the semiconductor substrate by heating the substrate.
Claim 3
Independent Claim
69 words
A method for forming an oxide on the surface of the semiconductor substrate, comprising: (A) placing the semiconductor substrate in a nitrogen atmosphere; and then (B) applying laser energy and introducing nitrogen to a first portion of the semiconductor substrate and not a second portion of the semiconductor substrate; and (C) forming said oxide on both the first and second portions of the semiconductor substrate by heating the substrate.
Claim 4
Independent Claim
69 words
A method for forming an oxide on the surface of the semiconductor substrate, comprising: (A) placing the semiconductor substrate in a nitrogen atmosphere; and then (B) applying laser energy and introducing nitrogen to a first portion of the semiconductor substrate and not a second portion of the semiconductor substrate; and (C) forming said oxide on both the first and second portions of the semiconductor substrate by heating the substrate.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein said step (b) comprises applying a directional energy beam through a patterned reflective reticle.
Claim 6
Dependent Claim
25 words
The method of claim 1 further including the step, prior to step (a), of applying a mask layer to the surface of the semiconductor substrate.
Claim 7
Dependent Claim
13 words
The method of claim 1 wherein the ambient atmosphere is a nitrogen-containing atmosphere.
Claim 8
Dependent Claim
48 words
The method of claim 1 wherein the method further includes the step, prior to step (c), of: applying a second dose of laser energy to the portion of the substrate, the energy being sufficient to melt the surface of the substrate to a sufficient depth of the portion.
Claim 9
Dependent Claim
33 words
The method of claim 1 wherein the method further includes the step, prior to step (c), of: annealing the substrate to remove damage caused by the incorporation or deposition of the growth-inhibiting compound.
Claim 10
Dependent Claim
25 words
The method of claim 1 wherein step (c) comprises placing the substrate in an oxygen atmosphere at a temperature in the range of 900° C.
Claim 11
Dependent Claim
21 words
The method of claim 2 wherein said step of applying laser energy comprises applying laser energy through a patterned reflective reticle.
Claim 12
Dependent Claim
27 words
The method of claim 2 further including the step, prior to the step of placing, of applying a mask layer to the surface of the semiconductor substrate.
Claim 13
Dependent Claim
35 words
The method of claim 2 wherein the step of applying laser energy comprises applying sufficient energy from an excimer laser to melt the substrate surface to a depth in the first portion of the substrate.
Claim 14
Dependent Claim
18 words
The method of claim 11 wherein the energy is greater than or equal to 650 mJ/cm 2 .
Claim 15
Dependent Claim
14 words
The method of claim 11 wherein the laser has a wavelength of 308 nm.
Claim 16
Dependent Claim
39 words
The method of claim 2 wherein the step of applying laser energy comprises the step of applying a succession of pulses from an excimer laser at an energy below an energy necessary to cause liquification of the substrate surface.
Claim 17
Dependent Claim
21 words
The method of claim 14 wherein the energy is in a range of about 325 mJ/cm 2 -650 mJ/cm 2 .
Claim 18
Dependent Claim
13 words
The method of claim 15 wherein the repetition rate is about 9 MHZ.
Claim 19
Dependent Claim
44 words
The method of claim 2 further including the step, following step (c), of: applying a second dose of laser energy to the portion of the substrate, the energy being sufficient to melt the surface of the substrate to a sufficient depth of the portion.
Claim 20
Independent Claim
116 words
A method for forming an oxide on the surface of a semiconductor substrate, comprising: (a) immersing the semiconductor substrate in a nitrogen containing atmosphere; (b) applying a laser to a portion of the substrate to induce incorporation or deposition of the nitrogen into the portion of the substrate to a depth dependent upon the strength of the laser energy directed at the surface of the substrate; and (c) forming the oxide on the surface of the substrate by heating the substrate such that the portion of the oxide formed over the selected portion is formed at a different rate than a portion of the oxide formed over regions of the substrate not including the selected portion.
Claim 21
Independent Claim
116 words
A method for forming an oxide on the surface of a semiconductor substrate, comprising: (a) immersing the semiconductor substrate in a nitrogen containing atmosphere; (b) applying a laser to a portion of the substrate to induce incorporation or deposition of the nitrogen into the portion of the substrate to a depth dependent upon the strength of the laser energy directed at the surface of the substrate; and (c) forming the oxide on the surface of the substrate by heating the substrate such that the portion of the oxide formed over the selected portion is formed at a different rate than a portion of the oxide formed over regions of the substrate not including the selected portion.
Claim 22
Dependent Claim
23 words
The method of claim 18 wherein said step of applying laser energy comprises applying a directional energy beam through a patterned reflective reticle.
Claim 23
Dependent Claim
26 words
The method of claim 18 further including the step, prior to the step (a), of applying a mask layer to the surface of the semiconductor substrate.
Claim 24
Dependent Claim
32 words
The method of claim 18 wherein the step (b) comprises applying sufficient energy from an excimer laser to melt the laser surface to a depth in the first portion of the substrate.
Claim 25
Dependent Claim
18 words
The method of claim 21 wherein the energy is in a range of 650 mJ/cm 2 or greater.
Claim 26
Dependent Claim
14 words
The method of claim 21 wherein the laser has a wavelength of 308 nm.
Claim 27
Dependent Claim
36 words
The method of claim 18 wherein the step (b) comprises the step of applying a succession of pulses from an excimer laser at an energy below an energy necessary to cause liquification of the substrate surface.
Claim 28
Dependent Claim
21 words
The method of claim 24 wherein the energy is in a range of about 325 mJ/cm 2 -650 mJ/cm 2 .
Claim 29
Dependent Claim
13 words
The method of claim 25 wherein the repetition rate is about 9 MHZ.
Claim 30
Dependent Claim
44 words
The method of claim 18 further including the step, following step (c), of: applying a second dose of laser energy to the portion of the substrate, the energy being sufficient to melt the surface of the substrate to a sufficient depth of the portion.
Claim 31
Independent Claim
128 words
A method for forming an oxide on a semiconductor substrate, comprising the steps of: (a) forming a mask layer on the surface of the semiconductor substrate; (b) immersing the semiconductor substrate in a nitrogen containing atmosphere; (c) applying a laser to a portion of the substrate to induce incorporation or deposition of the nitrogen into the portion of the substrate to a depth dependent upon the strength of the laser energy directed at the surface of the substrate; and (d) forming the oxide on the surface of the substrate by heating the substrate such that the portion of the oxide formed over the selected portion is formed at a different rate than a portion of the oxide formed over regions of the substrate not including the selected portion.
Claim 32
Independent Claim
128 words
A method for forming an oxide on a semiconductor substrate, comprising the steps of: (a) forming a mask layer on the surface of the semiconductor substrate; (b) immersing the semiconductor substrate in a nitrogen containing atmosphere; (c) applying a laser to a portion of the substrate to induce incorporation or deposition of the nitrogen into the portion of the substrate to a depth dependent upon the strength of the laser energy directed at the surface of the substrate; and (d) forming the oxide on the surface of the substrate by heating the substrate such that the portion of the oxide formed over the selected portion is formed at a different rate than a portion of the oxide formed over regions of the substrate not including the selected portion.
Claim 33
Dependent Claim
23 words
The method of claim 28 wherein said step of applying laser energy comprises applying a directional energy beam through a patterned reflective reticle.
Claim 34
Dependent Claim
35 words
The method of claim 28 wherein the step of applying laser energy comprises applying sufficient energy from an excimer laser to melt the laser surface to a depth in the first portion of the substrate.
Claim 35
Dependent Claim
18 words
The method of claim 30 wherein the energy is in a range of 650 mJ/cm 2 or greater.
Claim 36
Dependent Claim
14 words
The method of claim 30 wherein the laser has a wavelength of 308 nm.
Claim 37
Dependent Claim
14 words
The method of claim 30 wherein the laser has a wavelength of 193 nm.
Claim 38
Dependent Claim
39 words
The method of claim 28 wherein the step of applying laser energy comprises the step of applying a succession of pulses from an excimer laser at an energy below an energy necessary to cause liquification of the substrate surface.
Claim 39
Dependent Claim
21 words
The method of claim 34 wherein the energy is in a range of about 325 mJ/cm 2 -650 mJ/cm 2 .
Claim 40
Dependent Claim
13 words
The method of claim 35 wherein the repetition rate is about 9 MHZ.
Claim 41
Dependent Claim
44 words
The method of claim 28 further including the step, following step (c), of: applying a second dose of laser energy to the portion of the substrate, the energy being sufficient to melt the surface of the substrate to a sufficient depth of the portion.
Claim 42
Independent Claim
66 words
A method for forming an oxide on the surface of a semiconductor substrate, the oxide having at least a first thickness and a second thickness, comprising the steps of: (a) gas immersion laser doping a region of the substrate with nitrogen; and (b) heating the substrate including the gas immersion doped region in an oxygen atmosphere to form said oxide having a first and second thickness.
Claim 43
Independent Claim
66 words
A method for forming an oxide on the surface of a semiconductor substrate, the oxide having at least a first thickness and a second thickness, comprising the steps of: (a) gas immersion laser doping a region of the substrate with nitrogen; and (b) heating the substrate including the gas immersion doped region in an oxygen atmosphere to form said oxide having a first and second thickness.
Claim 44
Dependent Claim
64 words
The method of claim 38 wherein said step (a) comprises the steps of: (a) immersing the semiconductor substrate in a nitrogen containing atmosphere; and (b) applying a laser to a portion of the substrate to induce deposition of the nitrogen into the portion of the substrate to a depth dependent upon the strength of the laser energy directed at the surface of the substrate.
Claim 45
Dependent Claim
21 words
The method of claim 39 wherein said step (a) further comprises applying a directional energy beam through a patterned reflective reticle.
Claim 46
Dependent Claim
48 words
The method of claim 38 wherein the method further includes the step, prior to step (b), of: applying a second dose of laser energy to the portion of the substrate, the energy being sufficient to melt the surface of the substrate to a sufficient depth of the portion.
Claim 47
Dependent Claim
25 words
The method of claim 38 wherein step (b) comprises placing the substrate in an oxygen atmosphere at a temperature in the range of 900° C.
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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) | 2002-05-17 | 2002-11-16 | 2003-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-17 | 2006-11-16 | 2007-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-17 | 2010-11-16 | 2011-05-18 | $7700.00 | Window Closed / Lapsed |