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US6177145B1 Expired / Lapsed US ⏱️ 0.0 years remaining

Semiconductor processing method of making electrical contact to a node

Assignee: Micron Technology Inc
•
Filing: 1998-06-08
•
Granted: 2001-01-23
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Expires: 2018-06-08
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Abstract

Abstract The invention includes a semiconductor processing method of making electrical contact to a node. An insulating layer is formed over a substrate, and an opening is formed through the insulating layer to the substrate. A layer of electrically conductive material is formed within the opening. The electrically conductive material is capable of absorbing oxygen when exposed to an oxygen containing ambient. The conductive material is exposed to a plasma to densify at least an outermost exposed portion of the conductive material and reduce a capability of the layer to absorb oxygen when exposed to the oxygen containing ambient. The layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.

Inventors

  • 👤 Garo J. Derderian
  • 👤 Gurtej S. Sandhu

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 08:58
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/02; C23C16/0272; C23C16/0281; C23C16/04; C23C16/045; C23C16/22; C23C16/30; C23C16/34; C23C16/44; C23C16/455; C23C16/45523; C23C16/45525; C23C16/45527; C23C16/45534; C23C16/45536; C23C16/4554; C23C16/56; H; H10; H10P; H10P95/00; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/059

Claims Analysis

Total Claims: 44
Claim 1
Independent Claim 121 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer over a substrate; forming an opening through the insulating layer to the substrate; forming a layer of electrically conductive material comprising carbon within the opening; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; exposing the conductive material to a plasma to densify at least an outermost exposed portion of the conductive material and reduce a capability of the layer of conductive material to absorb oxygen when exposed to the oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 2
Dependent Claim 121 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer over a substrate; forming an opening through the insulating layer to the substrate; forming a layer of electrically conductive material comprising carbon within the opening; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; exposing the conductive material to a plasma to densify at least an outermost exposed portion of the conductive material and reduce a capability of the layer of conductive material to absorb oxygen when exposed to the oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 3
Dependent Claim 15 words
The semiconductor processing method of claim 1 wherein the electrically conductive material predominately comprises TiN.
Claim 4
Dependent Claim 17 words
The semiconductor processing method of claim 1 wherein the electrically conductive material comprises titanium, carbon and nitrogen.
Claim 5
Dependent Claim 140 words
A semiconductor processing method of making electrical contact to a substrate comprising the following steps: forming a layer of electrically conductive material comprising carbon over a substrate; the electrically conductive material being undesirably capable of absorbing oxygen, when exposed to an oxygen containing ambient, effective to render such material less electrically conductive; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material, and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to the oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 6
Dependent Claim 140 words
A semiconductor processing method of making electrical contact to a substrate comprising the following steps: forming a layer of electrically conductive material comprising carbon over a substrate; the electrically conductive material being undesirably capable of absorbing oxygen, when exposed to an oxygen containing ambient, effective to render such material less electrically conductive; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material, and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to the oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 7
Dependent Claim 125 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming a contact opening in the insulating layer to the substrate; forming a layer of electrically conductive material comprising carbon within the contact opening, the electrically conductive material layer being capable of absorbing oxygen to a first degree as formed; exposing the electrically conductive layer to a plasma sufficient to render at least a portion of the layer to a capability of absorbing oxygen to a second degree, the second degree being less than the first degree; and wherein the electrically conductive layer is not exposed to oxygen before being exposed to the plasma.
Claim 8
Dependent Claim 125 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming a contact opening in the insulating layer to the substrate; forming a layer of electrically conductive material comprising carbon within the contact opening, the electrically conductive material layer being capable of absorbing oxygen to a first degree as formed; exposing the electrically conductive layer to a plasma sufficient to render at least a portion of the layer to a capability of absorbing oxygen to a second degree, the second degree being less than the first degree; and wherein the electrically conductive layer is not exposed to oxygen before being exposed to the plasma.
Claim 9
Dependent Claim 121 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming a contact opening in the insulating layer to the substrate; forming a layer predominately comprising TiN within the contact opening, the TiN layer further comprising carbon and being capable of absorbing oxygen to a first degree as formed; exposing the TiN layer to a plasma sufficient to render at least a portion of the TiN layer capable of absorbing oxygen to a second degree, the second degree being less than the first degree; and wherein the TiN layer is not exposed to oxygen before being exposed to the plasma.
Claim 10
Dependent Claim 121 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming a contact opening in the insulating layer to the substrate; forming a layer predominately comprising TiN within the contact opening, the TiN layer further comprising carbon and being capable of absorbing oxygen to a first degree as formed; exposing the TiN layer to a plasma sufficient to render at least a portion of the TiN layer capable of absorbing oxygen to a second degree, the second degree being less than the first degree; and wherein the TiN layer is not exposed to oxygen before being exposed to the plasma.
Claim 11
Dependent Claim 160 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming an opening in the insulating layer to the substrate; forming a layer of electrically conductive material comprising carbon to substantially fill the contact opening; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to an oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 12
Dependent Claim 160 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming an opening in the insulating layer to the substrate; forming a layer of electrically conductive material comprising carbon to substantially fill the contact opening; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to an oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 13
Dependent Claim 15 words
The semiconductor processing method of claim 7 wherein the electrically conductive material predominately comprises TiN.
Claim 14
Dependent Claim 17 words
The semiconductor processing method of claim 7 wherein the electrically conductive material comprises titanium, carbon and nitrogen.
Claim 15
Dependent Claim 38 words
The semiconductor processing method of claim 7 wherein the gas and plasma generated therefrom having a component which is effective when in an activated state to interact with a component of the conductive layer to remove carbon therefrom.
Claim 16
Dependent Claim 46 words
The semiconductor processing method of claim 7 wherein the electrically conductive material layer as-provided comprises hydrocarbon, the gas and plasma generated therefrom having a component which is effective when in an activated state to interact with a component of the conductive layer to remove hydrocarbon therefrom.
Claim 17
Dependent Claim 46 words
The semiconductor processing method of claim 7 wherein, the electrically conductive material predominately comprises TiN; and the gas and plasma generated therefrom having a component which is effective when in an activated state to interact with a component of the conductive layer to remove carbon therefrom.
Claim 18
Dependent Claim 24 words
The semiconductor processing method of claim 7 wherein the plasma exposure densifies only an outer exposed 100 Angstroms to 500 Angstroms of the material.
Claim 19
Dependent Claim 288 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made, the substrate comprising silicon having a diffusion region provided therein; forming a contact opening in the insulating layer to the diffusion region; depositing a layer of electrically conductive material to a thickness effective for patterning of a conductive line over the insulating layer and within the contact opening to substantially fill the contact opening; the layer of electrically conductive material being in electrical contact with the diffusion region; the electrically conductive material being undesirably capable of absorbing oxygen, when exposed to an oxygen containing ambient; providing the substrate with the deposited layer of electrically conductive material within a reactor, injecting a gas into the reactor, generating a first plasma from the gas against the material, and exposing the material to the first plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to an oxygen containing ambient; patterning the deposited layer into a conductive line which is in electrical connection with the material within the contact opening to expose sidewalls of the electrically conductive material above the insulating layer; and providing the substrate with the conductive line of the electrically conductive material within a reactor, injecting a gas into the reactor, generating a second plasma from the gas against the material of the line and exposing the line sidewall material to the second plasma to densify at least an outermost exposed portion of such sidewall material and render the sidewalls less capable of absorbing oxygen when exposed to an oxygen containing ambient.
Claim 20
Dependent Claim 288 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made, the substrate comprising silicon having a diffusion region provided therein; forming a contact opening in the insulating layer to the diffusion region; depositing a layer of electrically conductive material to a thickness effective for patterning of a conductive line over the insulating layer and within the contact opening to substantially fill the contact opening; the layer of electrically conductive material being in electrical contact with the diffusion region; the electrically conductive material being undesirably capable of absorbing oxygen, when exposed to an oxygen containing ambient; providing the substrate with the deposited layer of electrically conductive material within a reactor, injecting a gas into the reactor, generating a first plasma from the gas against the material, and exposing the material to the first plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to an oxygen containing ambient; patterning the deposited layer into a conductive line which is in electrical connection with the material within the contact opening to expose sidewalls of the electrically conductive material above the insulating layer; and providing the substrate with the conductive line of the electrically conductive material within a reactor, injecting a gas into the reactor, generating a second plasma from the gas against the material of the line and exposing the line sidewall material to the second plasma to densify at least an outermost exposed portion of such sidewall material and render the sidewalls less capable of absorbing oxygen when exposed to an oxygen containing ambient.
Claim 21
Dependent Claim 136 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer over a substrate; forming an opening through the insulating layer to the substrate; forming a layer of electrically conductive material within the opening; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; exposing the conductive material to a plasma to densify at least an outermost exposed portion of the conductive material and reduce a capability of the layer of conductive material to absorb oxygen when exposed to the oxygen containing ambient; wherein the plasma is generated from a gas comprising H 2 , Ar, or a mixture thereof; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 22
Dependent Claim 136 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer over a substrate; forming an opening through the insulating layer to the substrate; forming a layer of electrically conductive material within the opening; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; exposing the conductive material to a plasma to densify at least an outermost exposed portion of the conductive material and reduce a capability of the layer of conductive material to absorb oxygen when exposed to the oxygen containing ambient; wherein the plasma is generated from a gas comprising H 2 , Ar, or a mixture thereof; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 23
Dependent Claim 15 words
The semiconductor processing method of claim 15 wherein the electrically conductive material predominantly comprises TiN.
Claim 24
Dependent Claim 150 words
A semiconductor processing method of making electrical contact to a substrate comprising the following steps: forming a layer of electrically conductive material over a substrate; the electrically conductive material being undesirably capable of absorbing oxygen, when exposed to an oxygen containing ambient, effective to render such material less electrically conductive; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material, and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to the oxygen containing ambient; wherein the gas comprises H 2 , Ar, or a mixture thereof; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 25
Dependent Claim 150 words
A semiconductor processing method of making electrical contact to a substrate comprising the following steps: forming a layer of electrically conductive material over a substrate; the electrically conductive material being undesirably capable of absorbing oxygen, when exposed to an oxygen containing ambient, effective to render such material less electrically conductive; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material, and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to the oxygen containing ambient; wherein the gas comprises H 2 , Ar, or a mixture thereof; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 26
Dependent Claim 15 words
The semiconductor processing method of claim 17 wherein the electrically conductive material predominantly comprises TiN.
Claim 27
Dependent Claim 137 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming a contact opening in the insulating layer to the substrate; forming a layer of electrically conductive material within the contact opening, the electrically conductive layer being capable of absorbing oxygen to a first degree as formed; exposing the electrically conductive layer to a plasma sufficient to render at least a portion of the layer capable of absorbing oxygen to a second degree, the second degree being less than the first degree; wherein the plasma is generated from a gas comprising H 2 , Ar, or a mixture thereof; and wherein the electrically conductive layer is not exposed to oxygen before being exposed to the plasma.
Claim 28
Dependent Claim 137 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming a contact opening in the insulating layer to the substrate; forming a layer of electrically conductive material within the contact opening, the electrically conductive layer being capable of absorbing oxygen to a first degree as formed; exposing the electrically conductive layer to a plasma sufficient to render at least a portion of the layer capable of absorbing oxygen to a second degree, the second degree being less than the first degree; wherein the plasma is generated from a gas comprising H 2 , Ar, or a mixture thereof; and wherein the electrically conductive layer is not exposed to oxygen before being exposed to the plasma.
Claim 29
Dependent Claim 170 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming an opening in the insulating layer to the substrate; forming a layer of electrically conductive material to substantially fill the contact opening; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to an oxygen containing ambient; wherein the gas comprises H 2 , Ar, or a mixture thereof; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 30
Dependent Claim 170 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming an opening in the insulating layer to the substrate; forming a layer of electrically conductive material to substantially fill the contact opening; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to an oxygen containing ambient; wherein the gas comprises H 2 , Ar, or a mixture thereof; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 31
Dependent Claim 24 words
The semiconductor processing method of claim 20 wherein the plasma exposure densifies only an outer exposed 100 Angstroms to 500 Angstroms of the material.
Claim 32
Dependent Claim 129 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer over a substrate; forming an opening through the insulating layer to the substrate; forming a layer of electrically conductive material within the opening; the electrically conductive layer comprising a metal other than Ti; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; exposing the conductive material to a plasma to densify at least an outermost exposed portion of the conductive material and reduce a capability of the layer of conductive material to absorb oxygen when exposed to the oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 33
Dependent Claim 129 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer over a substrate; forming an opening through the insulating layer to the substrate; forming a layer of electrically conductive material within the opening; the electrically conductive layer comprising a metal other than Ti; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; exposing the conductive material to a plasma to densify at least an outermost exposed portion of the conductive material and reduce a capability of the layer of conductive material to absorb oxygen when exposed to the oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 34
Dependent Claim 18 words
The semiconductor processing method of claim 22 wherein the metal other than Ti comprises Al, W or Cu.
Claim 35
Dependent Claim 148 words
A semiconductor processing method of making electrical contact to a substrate comprising the following steps: forming a layer of electrically conductive material over a substrate; the electrically conductive layer comprising a metal other than Ti; the electrically conductive material being undesirably capable of absorbing oxygen, when exposed to an oxygen containing ambient, effective to render such material less electrically conductive; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material, and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to the oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 36
Dependent Claim 148 words
A semiconductor processing method of making electrical contact to a substrate comprising the following steps: forming a layer of electrically conductive material over a substrate; the electrically conductive layer comprising a metal other than Ti; the electrically conductive material being undesirably capable of absorbing oxygen, when exposed to an oxygen containing ambient, effective to render such material less electrically conductive; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material, and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to the oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 37
Dependent Claim 18 words
The semiconductor processing method of claim 24 wherein the metal other than Ti comprises Al, W, or Cu.
Claim 38
Dependent Claim 133 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming a contact opening in the insulating layer to the substrate; forming a layer of electrically conductive material within the contact opening, the electrically conductive layer comprising a metal other than Ti; the electrically conductive material layer being capable of absorbing oxygen to a first degree as formed; exposing the electrically conductive layer to a plasma sufficient to render at least a portion of the layer to a capability of absorbing oxygen to a second degree, the second degree being less than the first degree; and wherein the electrically conductive layer is not exposed to oxygen before being exposed to the plasma.
Claim 39
Dependent Claim 133 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming a contact opening in the insulating layer to the substrate; forming a layer of electrically conductive material within the contact opening, the electrically conductive layer comprising a metal other than Ti; the electrically conductive material layer being capable of absorbing oxygen to a first degree as formed; exposing the electrically conductive layer to a plasma sufficient to render at least a portion of the layer to a capability of absorbing oxygen to a second degree, the second degree being less than the first degree; and wherein the electrically conductive layer is not exposed to oxygen before being exposed to the plasma.
Claim 40
Dependent Claim 18 words
The semiconductor processing method of claim 26 wherein the metal other than Ti comprises Al, W or Cu.
Claim 41
Dependent Claim 168 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming an opening in the insulating layer to the substrate; forming a layer of electrically conductive material to substantially fill the contact opening; the electrically conductive layer comprising a metal other than Ti; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to an oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 42
Dependent Claim 168 words
A semiconductor processing method of making electrical contact to a node comprising the following steps: forming an insulating layer relative to a substrate to which electrical connection is to be made; forming an opening in the insulating layer to the substrate; forming a layer of electrically conductive material to substantially fill the contact opening; the electrically conductive layer comprising a metal other than Ti; the electrically conductive material being capable of absorbing oxygen when exposed to an oxygen containing ambient; providing the substrate with the provided layer of electrically conductive material within a reactor, injecting a gas into the reactor and generating a plasma from the gas against the material and exposing the material to the plasma to densify at least an outermost exposed portion of such material and render the layer of material less capable of absorbing oxygen when exposed to an oxygen containing ambient; and wherein the layer of electrically conductive material is not exposed to the oxygen containing ambient before being exposed to the plasma.
Claim 43
Dependent Claim 18 words
The semiconductor processing method of claim 28 wherein the metal other than Ti comprises Al, W or Cu.
Claim 44
Dependent Claim 24 words
The semiconductor processing method of claim 28 wherein the plasma exposure densifies only an outer exposed 100 Angstroms to 500 Angstroms of the material.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2004-01-23 2004-07-24 2005-01-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2008-01-23 2008-07-24 2009-01-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2012-01-23 2012-07-24 2013-01-23 $7700.00 Window Closed / Lapsed

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