EP0488628A2
Expired / Lapsed
EP
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Method of producing an aluminum stacked contact/via for multilayer interconnections
Assignee: STMicroelectronics lnc USA
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Filing: 1991-11-26
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Granted: —
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Expires: 2011-11-26
Abstract
Abstract A method is provided for forming improved quality interlevel aluminum contacts in semiconductor integrated circuits. A contact opening is formed through an insulating layer. A barrier layer is deposited over the surface of the integrated circuit. An aluminum layer is then deposited at relatively low deposition rates at a temperature which allows improved surface migration of the deposited aluminum atoms. Aluminum deposited under these conditions tends to fill contact vias without the formation of voids. The low temperature deposition step can be initiated by depositing aluminum while a wafer containing the integrated circuit device is being heated from cooler temperatures within the deposition chamber.
Inventors
- 👤 Fu-Tai Liou
- 👤 Fusen E. Chen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 01:49
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/033; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10W20/056
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
77 words
A method of forming interlevel contacts in integrated circuits, comprising the steps of: forming a first contact opening in a first insulating layer to expose a conducting region beneath; forming a first barrier layer over the first insulating layer and in the first contact opening, and; depositing an aluminium layer continuously on the integrated circuit during an increase in the temperature of the integrated circuit beginning below 350°C and increasing to a deposition temperature less than 500°C.
Claim 2
Dependent Claim
23 words
The method of claim 1, wherein the first contact opening is formed over a previously fabricated contact to a lower level conducting structure.
Claim 3
Dependent Claim
30 words
The method of claim 1 or 2, wherein the first barrier layer comprises a refractory metal alloy, metal silicide or metal nitride, or a composite of any two of these.
Claim 4
Independent Claim
21 words
The method of claims 1 to 3, wherein the aluminum layer depositing step is performed at a preselected rate of deposition.
Claim 5
Dependent Claim
25 words
The method of claim 4, wherein the preselected deposition rate is changed to a second preselected rate before the integrated circuit reaches the deposition temperature.
Claim 6
Independent Claim
93 words
The method of any preceding claim further comprising: forming a second insulating layer disposed over the aluminum layer and the first insulating layer; forming a second contact opening in the second insulating layer, wherein the second contact opening exposes a portion of the aluminum layer; forming a second barrier layer over the second insulating layer and in the second contact opening; depositing a second aluminum layer continuously on the integrated circuit during an increase in the temperature of the integrated circuit beginning below 350°C and increasing to a deposition temperature less than 500°C.
Claim 7
Dependent Claim
28 words
The method of claim 6, wherein the technique of continuously depositing aluminium during a specified temperature range may be varied if there will not be a third contact.
Claim 8
Independent Claim
141 words
A method of forming interlevel aluminum contacts in integrated circuits, comprising the steps of: forming a first insulating layer over a conducting layer; forming an opening through the insulating layer to expose a portion of the conducting layer; depositing a barrier layer over the insulating layer and the exposed portion of the conducting layer; depositing an aluminum layer continuously on the integrated circuit while the temperature of the integrated circuit is raised from below approximately 50°C to a preselected value between approximately 400° and approximately 500°C; after the temperature has reached the preselected value, depositing the aluminum layer on the integrated circuit to a desired thickness, and; during the desired thickness depositing step, controlling the rate at which the aluminum layer is deposited to allow deposited aluminum to migrate into the opening so as to provide a substantially complete contact fill.
Claim 9
Dependent Claim
37 words
The method of claim 8, wherein the controlling step comprises the step of: maintaining the deposition rate to be less than approximately (.7 * T) - 250 angstroms/sec where T lies between approximately 400°C and approximately 500°C.
Claim 10
Dependent Claim
29 words
The method of claim 8, wherein the deposition rate is varied, with one portion being faster than approximately 50 angstroms/sec, and another portion being lower than approximately 50 angstroms/sec.
Claim 11
Dependent Claim
24 words
The method of claim 10, wherein a last portion of the deposition step is performed at a deposition rate faster than approximately 100 angstroms/sec.
Claim 12
Dependent Claim
19 words
The method of claim 11, wherein a first deposition portion is performed at a rate above approximately 40 angstroms/sec.
Claim 13
Independent Claim
153 words
The method of claims 2 to 12, further comprising: forming a second insulating layer disposed over the aluminum layer and the first insulating layer; forming a second contact opening in the second insulating layer, wherein the second contact opening exposes a portion of the aluminum layer; forming a second barrier layer over the second insulating layer and in the second contact opening; depositing a second aluminum layer continuously on the integrated circuit while the temperature of the integrated circuit is raised from below approximately 350°C to a preselected value approximately 400°C and approximately 500°C; after the temperature has reached the preselected value, depositing the second aluminum layer on the integrated circuit to a desired thickness, and; during the desired thickness depositing step, controlling the rate at which the second aluminum layer is deposited to allow deposited aluminum to migrate into the second contact opening so as to provide a substantially complete contact fill.
References Cited (Backward Citations)
No citation records indexed.
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