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Publication numberUS20010049205 A1
Publication typeApplication
Application numberUS 09/410,234
Publication dateDec 6, 2001
Filing dateSep 30, 1999
Priority dateAug 21, 1997
Also published asUS5985770, US6372669
Publication number09410234, 410234, US 2001/0049205 A1, US 2001/049205 A1, US 20010049205 A1, US 20010049205A1, US 2001049205 A1, US 2001049205A1, US-A1-20010049205, US-A1-2001049205, US2001/0049205A1, US2001/049205A1, US20010049205 A1, US20010049205A1, US2001049205 A1, US2001049205A1
InventorsGurtej S. Sandhu, Ravi Iyer
Original AssigneeGurtej S. Sandhu, Ravi Iyer
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
After forming a layer comprising liquid silicon oxide precursor (especially SI(O4)4) onto a substrate, the layer is doped and transformed into a solid doped silicon oxide containing layer
US 20010049205 A1
Abstract
The invention comprises methods of depositing silicon oxide material onto a substrate. In but one aspect of the invention, a method of depositing a silicon oxide containing layer on a substrate includes initially forming a layer comprising liquid silicon oxide precursor onto a substrate. After forming the layer, the layer is doped and transformed into a solid doped silicon oxide containing layer on the substrate. In a preferred implementation, the doping is by gas phase doping and the liquid precursor comprises Si(OH)4. In the preferred implementation, the transformation occurs by raising the temperature of the deposited liquid precursor to a first elevated temperature and polymerizing the deposited liquid precursor on the substrate. The temperature is continued to be raised to a second elevated temperature higher than the first elevated temperature and a solid doped silicon oxide containing layer is formed on the substrate.
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Claims(41)
1. A method of depositing a silicon oxide containing layer on a substrate comprising:
forming a layer comprising liquid silicon oxide precursor onto a substrate; and
after, forming the layer, doping and transforming the layer into a solid doped silicon oxide containing layer on the substrate.
2. The method of depositing silicon oxide of
claim 1
wherein the doping occurs prior to the transforming.
3. The method of depositing silicon oxide of
claim 1
wherein the doping is completed prior to the transforming.
4. The method of depositing silicon oxide of
claim 1
wherein the doping comprises gas phase doping.
5. The method of depositing silicon oxide of
claim 1
wherein the doping comp rises gas phase doping using dopants provided as plasma proximate the layer.
6. The method of depositing silicon oxide of
claim 1
wherein the forming occurs in one processing chamber, the doping comprises gas phase doping using dopants provided as plasma proximate the layer, the dopants being formed as plasma external of the one processing chamber and being transported to the processing chamber.
7. The method of depositing silicon oxide of
claim 1
wherein the doping is conducted at a temperature of less than or equal to about 50° C.
8. The method of depositing silicon oxide of
claim 1
wherein the liquid silicon oxide precursor comprises Si(OH)4.
9. The method of depositing silicon oxide of
claim 1
wherein the liquid silicon oxide precursor consists essentially of Si(OH)4.
10. The method of depositing silicon oxide of
claim 1
wherein the transforming comprises polymerizing and depolymerizing.
11. The method of depositing silicon oxide of
claim 1
wherein the doping comprises a carbon containing dopant.
12. The method of depositing silicon oxide of
claim 1
wherein the doping comprises a dopant selected from the group consisting of phosphorus, fluorine, nitrogen carbon and boron, or mixtures thereof.
13. A method of depositing a silicon oxide containing layer on a substrate comprising:
forming a liquid silicon oxide precursor onto a substrate;
gas phase doping the liquid silicon oxide precursor on the substrate; and
transforming the liquid doped silicon oxide precursor into a solid doped silicon oxide containing layer on the substrate.
14. The method of depositing silicon oxide of
claim 13
wherein the forming and the gas phase doping is conducted at substantially the same temperature.
15. The method of depositing silicon oxide of
claim 13
wherein the forming and the gas phase doping is conducted at substantially the same pressure.
16. The method of depositing silicon oxide of
claim 13
wherein the doping is conducted at a temperature of less than or equal to about 50° C.
17. The method of depositing silicon oxide of
claim 13
wherein the transforming comprises polymerizing and depolymerizing.
18. The method of depositing silicon oxide of
claim 13
wherein the gas phase doping is completed prior to any substantial transforming.
19. The method of depositing silicon oxide of
claim 13
wherein the gas phase doping comprises a doping gas selected from the group consisting of PH3, B2H6, F2, NH3, NF3, C2F6 and CH4, or mixtures thereof.
20. The method of depositing silicon oxide of
claim 13
wherein the doping comprises using dopants provided as plasma proximate the layer.
21. The method of depositing silicon oxide of
claim 13
wherein the forming occurs in one processing chamber, the doping comprises using dopants provided as plasma proximate the layer, the dopants being formed as plasma external of the one processing chamber and being transported to the processing chamber.
22. A method of depositing a silicon oxide containing layer on a substrate comprising:
forming Si(OH)4 onto a substrate;
after the forming, doping the Si(OH)4 on the substrate; and
transforming the doped Si(OH)4 into a solid doped silicon oxide containing layer on the substrate.
23. The method of depositing silicon oxide of
claim 22
wherein the doping is completed prior to any substantial transforming.
24. The method of depositing silicon oxide of
claim 22
wherein the doping comprises gas phase doping.
25. The method of depositing silicon oxide of
claim 22
wherein the Si(OH)4 is in liquid form during the doping.
26. The method of depositing silicon oxide of
claim 22
wherein the doping is conducted at a temperature of less than or equal to about 50° C.
27. The method of depositing silicon oxide of
claim 22
wherein the transforming comprises polymerizing and depolymerizing.
28. The method of depositing silicon oxide of
claim 22
wherein the doping comprises gas phase doping using dopants provided as plasma proximate the layer.
29. The method of depositing silicon oxide of
claim 22
wherein the forming occurs in one processing chamber, the doping comprises gas phase doping using dopants provided as plasma proximate the layer, the dopants being formed as plasma external of the one processing chamber and being transported to the processing chamber.
30. A method of depositing a silicon oxide containing layer on a substrate comprising:
combining a silane gas with H2O2 at a temperature of from about −10° C. to about 30° C. to deposit a liquid polymer precursor onto a substrate;
gas phase doping the deposited liquid silicon oxide precursor on the substrate;
raising the temperature of the deposited liquid precursor to a first elevated temperature and polymerizing the deposited liquid precursor on the substrate; and
raising the temperature of the polymerized precursor to a second elevated temperature higher than the first elevated temperature and forming a solid doped silicon oxide containing layer on the substrate.
31. The method of depositing silicon oxide of
claim 30
wherein the deposit of liquid polymer precursor and the gas phase doping is conducted at substantially the same temperature.
32. The method of depositing silicon oxide of
claim 30
wherein the deposit of liquid polymer precursor and the gas phase doping is conducted at substantially the same pressure.
33. The method of depositing silicon oxide of
claim 30
wherein the first elevated temperature is at least about 100° C.
34. The method of depositing silicon oxide of
claim 30
wherein the second elevated temperature is at least about 350° C.
35. The method of depositing silicon oxide of
claim 30
wherein the first elevated temperature is at least about 100° C., and the second elevated temperature is at least about 350° C.
36. The method of depositing silicon oxide of
claim 30
wherein the doping is conducted at a temperature of less than or equal to about 50° C.
37. The method of depositing silicon oxide of
claim 30
wherein the gas phase doping is completed prior to the temperature raising to the first temperature.
38. The method of depositing silicon oxide of
claim 30
wherein the gas phase doping is completed prior to the polymerizing.
39. The method of depositing silicon oxide of
claim 30
wherein the gas phase doping comprises a doping gas selected from the group consisting of PH3, B2H6, F2, NH3, NF3, C2F6 and CH4, or mixtures thereof.
40. The method of depositing silicon oxide of
claim 30
wherein the doping comprises gas phase doping using dopants provided as is plasma proximate the layer.
41. The method of depositing silicon oxide of
claim 30
wherein the forming occurs in one processing chamber, the doping comprises gas phase doping using dopants provided as plasma proximate the layer, the dopants being formed as plasma external of the one processing chamber and being transported to the processing chamber.
Description
TECHNICAL FIELD

[0001] This invention relates to methods of depositing silicon oxides, such as silicon dioxide, over substrates.

BACKGROUND OF THE INVENTION

[0002] In methods of forming integrated circuits, it is frequently desired to isolate components of the integrated circuits from one another with insulative material. Such insulative material may comprise a number of materials, including for example, silicon dioxide, silicon nitride, and undoped semiconductive material. Although such materials have acceptable insulative properties in many applications, the materials disadvantageously have high dielectric constants which can lead to capacitive coupling between proximate conductive elements. For instance, silicon dioxide has a dielectric constant of about 4, silicon nitride has a dielectric constant of about 8, and undoped silicon has a dielectric constant of about 12. As circuit density increases with device geometries becoming smaller, the associated RC delay time increases, and hence there is a need to reduce capacitance below that of silicon dioxide material. Further as geometries have become smaller, it is much more difficult to conformally deposit layers into contact and other openings having high aspect ratio.

[0003] One known way of achieving desired lower dielectric constant silicon oxides, such as silicon dioxide, is to provide suitable dopant atoms within the material. Fluorine is but one example, to provide a fluorinated silicon oxide of the general formula FxSiOy.

[0004] One recently developed technique for achieving suitable deposition into substrates having high aspect ratio topography, has been developed by Electrotech Limited of Bristol, U.K., and is referred to as a Flowfill™ technology. In such process, SiH4 and H2O2 are separately introduced into a CVD chamber, such as a parallel plate reaction chamber. The reaction rate between SiH4 and H2O2 can be moderated by the introduction of nitrogen into the reaction chamber. The wafer is ideally maintained at a suitably low temperature, such as 0° C. at an exemplary pressure of 1 Torr to achieve formation of a silanol-type structure of the formula Si(OH)4 which condenses onto the wafer surface. Although the reaction occurs in the gas phase, the deposited Si(OH)4 is in the form of a very viscous liquid which flows to fill very small gaps on the wafer surface. And as deposition thickness increases, surface tension drives the deposited layer flat, thus forming a planarized layer over the substrate.

[0005] The liquid Si(OH)4 is typically then converted to a silicon dioxide structure by a two-step process. First, polymerization of the liquid film is promoted by increasing the temperature to about 100° C. to result in solidification and formation of a polymer layer. Thereafter, the temperature is raised to approximately 450° C. to depolymerize the substance and form SiO2. The depolymerization temperature also provides the advantage of driving undesired water from the resultant SiO2 layer.

[0006] Doping of such SiO2 layer has in the past been attempted by providing a dopant gas in combination with the gaseous H2O2 and gaseous SiH4 precursors during the initial formation of the Si(OH)4 liquid. Such deposition techniques have not met with much success and few if any suitable chemistries have been discovered for such to date. Most attempts for dopant incorporation in this manner invariably result in the loss of the desired flow-filling properties of the films.

[0007] Accordingly, it would be desirable to develop alternate methods of achieving doped silicon oxides, such as silicon dioxides, formed via a process using silicon oxide precursors, such as for example Si(OH)4.

SUMMARY OF INVENTION

[0008] The invention comprises methods of depositing silicon oxide material onto a substrate. In but one aspect of the invention, a method of depositing a silicon oxide containing layer on a substrate includes initially forming a layer comprising liquid silicon oxide precursor onto a substrate. After forming the layer, the layer is doped and transformed into a solid doped silicon oxide containing layer on the substrate. In a preferred implementation, the doping is by gas phase doping and the liquid precursor comprises Si(OH)4. In the preferred implementation, the transformation occurs by raising the temperature of the deposited liquid precursor to a first elevated temperature and polymerizing the deposited liquid precursor on the substrate. The temperature is continued to be raised to a second elevated temperature higher than the first elevated temperature and a solid doped silicon oxide containing layer is formed on the substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).

[0010] In accordance with one aspect of the invention, a silane gas, such as SiH4 or Si2H6, is combined with gaseous H2O2 within a chemical vapor deposition reactor at a temperature of from about −10° C. to about 30° C. to deposit a liquid polymer precursor onto a substrate within the reactor. A specific example wafer temperature is 0° C. with an exemplary pressure being 1 Torr. An example flow rate for a six liter reactor for SiH4 and H2O2 are 100 sccm and 0.75 gm/min, respectively. After about 120 minutes, a 6000 Angstroms thick liquid layer deposits. Such will form Si(OH)4, in this example in liquid form, onto a substrate. In this example, the deposited layer will consist essentially of Si(OH)4. Such provides but one example of forming a liquid silicon oxide precursor onto a substrate.

[0011] The deposited precursor is then doped, preferably by gas phase doping. on the substrate and substantially after its formation. The selected gas for preferred gas phase doping will be dependent on the ultimate desired dopant within the ultimate silicon oxide layer. For example, PH3 or phosphates such as trialkyl phosphates (i.e., trimethyl phosphate, triethyl phosphate) and phosphitees such as dialkyl phosphates (i.e. dimethyl phosphite) are example and preferred gases where the dopant is to be phosphorous. B2H6 is an example and preferred gas where the dopant is to be boron. NF3 and F2 are example and preferred gases (alone or in combination) where /the dopant material is to be fluorine. C2H6, trimethylsilane [(CH3)3SiH] and CH4 are example and preferred gases (alone or in combination) where the desired dopant is to be carbon. NF3 and NH3 are example and preferred gases (alone or in combination) where the dopant material is to be nitrogen. Various combinations of these gases could also be used to incorporate multiple different dopants. An example doping gas flow rate for a six liter reactor is 500 sccm.

[0012] Doping could also be provided using gas phase doping with plasma. For example, a plasma can be struck with the dopant gases proximate the formed liquid oxide precursor. The dopants are then available in activated states and may incorporate into the film more easily. Further, the dopants can be formed as plasma external of the processing chamber holding the wafer for doping, with the plasma dopants then being transported to the chamber holding the wafer for such doping.

[0013] Preferred reactor temperature and pressure for the gas phase doping is preferably at a temperature of less than or equal to about 50° C. and a pressure below 100 Torr. Temperature and pressure are ideally selected to achieve dopant diffusion through the total depth of the liquid layer.

[0014] The temperature of the liquid is also preferably maintained at or below 50° C. during the gas phase doping to avoid any substantially polymerizing of the liquid in advance of the doping. The temperature of the deposited liquid precursor is then raised to a first elevated temperature and polymerizing thereof occurs on the substrate. An exemplary and preferred first elevated temperature is at least about 100° C. The temperature is preferably held at this first elevated temperature for a period of time, for example 1 minute. Then, the temperature of the polymerized precursor is raised to a second elevated temperature which is higher than the first elevated temperature, and a solid doped silicon oxide containing layer is effectively formed on the substrate. An exemplary second elevated temperature is at least about 350° C., with 450° C. being preferred. Pressure is preferably maintained constant during both temperature ramps at, for example, form 0.1 Torr to 100 Torr.

[0015] Such provides but one example of transforming a substantially non-silicon oxide containing precursor layer into a solid doped silicon oxide containing layer on a substrate. The second elevated temperature effectively also provides an advantage of driving undesired water and other impurities from the layer. In the above-described exemplary transforming, such comprises initial polymerizing followed by depolymerizing of a silicon oxide precursor. Also preferably, the gas phase or other doping is completed prior to any substantial transforming of the doped layer to a polymer layer or silicon dioxide layer. However, gas phase or other doping with desired impurities could also occur during the temperature raising or other transformation. Thus in the preferred embodiment, the doping occurs both prior to the transforming, and is completed prior to the transforming. Also, the gas phase doping is completed prior to the temperature raising to the first temperature.

[0016] In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.

Referenced by
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US7097878Jun 22, 2004Aug 29, 2006Novellus Systems, Inc.Mixed alkoxy precursors and methods of their use for rapid vapor deposition of SiO2 films
US7109129Mar 9, 2005Sep 19, 2006Novellus Systems, Inc.Optimal operation of conformal silica deposition reactors
US7129189Jun 22, 2004Oct 31, 2006Novellus Systems, Inc.Aluminum phosphate incorporation in silica thin films produced by rapid surface catalyzed vapor deposition (RVD)
US7135418Mar 9, 2005Nov 14, 2006Novellus Systems, Inc.Optimal operation of conformal silica deposition reactors
US7148155Oct 26, 2004Dec 12, 2006Novellus Systems, Inc.Sequential deposition/anneal film densification method
US7163899Jan 5, 2006Jan 16, 2007Novellus Systems, Inc.Localized energy pulse rapid thermal anneal dielectric film densification method
US7202185Jun 22, 2004Apr 10, 2007Novellus Systems, Inc.Silica thin films produced by rapid surface catalyzed vapor deposition (RVD) using a nucleation layer
US7223707Dec 30, 2004May 29, 2007Novellus Systems, Inc.Dynamic rapid vapor deposition process for conformal silica laminates
US7271112Dec 30, 2004Sep 18, 2007Novellus Systems, Inc.Methods for forming high density, conformal, silica nanolaminate films via pulsed deposition layer in structures of confined geometry
US7288463Apr 28, 2006Oct 30, 2007Novellus Systems, Inc.Pulsed deposition layer gap fill with expansion material
US7294583Dec 23, 2004Nov 13, 2007Novellus Systems, Inc.Methods for the use of alkoxysilanol precursors for vapor deposition of SiO2 films
US7297608Jun 22, 2004Nov 20, 2007Novellus Systems, Inc.Method for controlling properties of conformal silica nanolaminates formed by rapid vapor deposition
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US7491653Dec 23, 2005Feb 17, 2009Novellus Systems, Inc.Metal-free catalysts for pulsed deposition layer process for conformal silica laminates
US7589028Nov 15, 2005Sep 15, 2009Novellus Systems, Inc.Hydroxyl bond removal and film densification method for oxide films using microwave post treatment
US7625820Jun 21, 2006Dec 1, 2009Novellus Systems, Inc.Method of selective coverage of high aspect ratio structures with a conformal film
US7863190Nov 20, 2009Jan 4, 2011Novellus Systems, Inc.Method of selective coverage of high aspect ratio structures with a conformal film
US7923383 *Mar 28, 2003Apr 12, 2011Tokyo Electron LimitedMethod and apparatus for treating a semi-conductor substrate
US8093713 *Feb 9, 2007Jan 10, 2012Infineon Technologies AgModule with silicon-based layer
US8697497Oct 26, 2011Apr 15, 2014Infineon Technologies AgModule with silicon-based layer
Classifications
U.S. Classification438/787, 438/782, 257/E21.279, 438/781
International ClassificationC23C16/30, H01L21/316
Cooperative ClassificationH01L21/02271, H01L21/31612, H01L21/0214, H01L21/02131, H01L21/02126, C23C16/30, H01L21/02129
European ClassificationH01L21/02K2C1L1F, H01L21/02K2C1L1, H01L21/02K2C1L1B, H01L21/02K2C1L1P, H01L21/02K2E3B6, C23C16/30, H01L21/316B2B
Legal Events
DateCodeEventDescription
Jun 3, 2014FPExpired due to failure to pay maintenance fee
Effective date: 20140416
Apr 16, 2014LAPSLapse for failure to pay maintenance fees
Nov 22, 2013REMIMaintenance fee reminder mailed
Sep 16, 2009FPAYFee payment
Year of fee payment: 8
Sep 23, 2005FPAYFee payment
Year of fee payment: 4
Jan 7, 2003CCCertificate of correction