Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3916822 A
Publication typeGrant
Publication dateNov 4, 1975
Filing dateApr 26, 1974
Priority dateApr 26, 1974
Publication numberUS 3916822 A, US 3916822A, US-A-3916822, US3916822 A, US3916822A
InventorsRobinson Mcdonald
Original AssigneeBell Telephone Labor Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Chemical vapor deposition reactor
US 3916822 A
Abstract
A chemical vapor deposition reactor produces deposits which are uniform in composition and thickness by minimizing convective currents in the immediate vicinity of the substrate. Heating of the substrate, positioning the substrate to face in a downward direction at the upper extremity of an essentially convection-free zone, and a radiation shield are utilized.
Images(1)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

' United States Patent 91 Robinson Nov. 4, 1975 CHEMICAL VAPOR DEPOSITION REACTOR [75] Inventor: McDonald Robinson, Chester, NJ.

[73] Assignee: Bell Telephone Laboratories,

Incorporated, Murray Hill, NJ.

3,677,329 7/1972 Kirkpatrick 165/105 3,690,635 9/1972 I-Iarker et a1 l18/49.5 X

FOREIGN PATENTS OR APPLICATIONS 218,262 5/1968 U.S.S.R 118/49.5

OTHER PUBLICATIONS Western Electric Co. Tech. Dig. Apparatus For The Deposition Of Silicon Nitride, Whitner, R. A., No. 11, (July 1968) pp. 5,6.

Primary Examiner-M0rris Kaplan Attorney, Agent, or Firm-G. S. Indig [57] ABSTRACT A chemical vapor deposition reactor produces deposits which are uniform in composition and thickness by minimizing convective currents in the immediate vicinity of the substrate. Heating of the substrate, positioning the substrate to face in a downward direction at the upper extremity of an essentially convectionfree zone, and a radiation shield are utilized.

6 Claims, 1 Drawing Figure U.S. Patent Nov. 4, 1975 H i K 1 CHEMICAL VAPOR DEPOSITION REACTOR BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is concerned with the desposition of films on substrates; the Substance of the film being produced by a chemical reaction involving a gaseous phase.

2. Description of the Prior Art Chemical vapor deposition (abbreviated in the following as CVD) is a method of plating solid objects in which deposits are produced by chemical reactions near, at, or on the surface of a substrate. The method involves the introduction of one or more gaseous reactants into the vicinity of a substratewhere the substance to be deposited is produced by a change in chemical state such as a breakdown or a combination of reactants. CVD has found a variety of commercial applications; examples are the metallization of mirrors, the pigmentation, reinforcing, protection, and decoration of surfaces, and the manufacture of semiconductor devices and integrated circuitry..CVD can be used to deposit elemental substances as well as chemical compounds such as bromides, carbides, nitrides, oxides and silicides. Deposited films may be amorphous, polycrystalline, or epitaxial and they may be electrically insulating, semiconducting, or conducting. A survey of fundamentals, techniques, and applications of CVD is given in C. F. Powell et al (Ed.), VapbnDeposition, John Wiley and sons, Inc., 1966.

In many applications of films deposited byCVD the uniformity in thickness and composition of the deposit is a major concern; this is the case, for instance, with deposited films as they are used in the semiconductor industry. One apparatus designed to produce filmsof superior uniformity is the CVD device proposed in F. H. Nicoll, The Use of Close Spacing in Chemical- Transport Systems for Growing Epitaxial Layers of Semiconductors, Journal of the Electrochemical Society, Vol. 110, November 1963, pp. 1165-1167, where the source material is placedparall el to and at close range of the substrate. Howeve'r',the design of this device limits its use to solid source materials and does not allow for the introduction of gaseous reactants.

SUMMARY OF THE INVENTION The invention represents a chemical vapor deposition reactor which, by minimizing convective currents in the vicinity of the substrate, produces films of superior uniformity.

Convection is prevented (1) by positioning the substrate at the upper boundary of the zone into which gaseous reactants are introduced, (2) by orienting the substrate to face in a downward direction, (3) by uniformly heating the substrate and the gases from above, and (4) by utilizing a radiation shield between the manifold through which gaseous components are introduced and the zone in the immediate vicinity of the substrate.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE is a cross sectional view of an embodi ment of the invention.

DETAILED DESCRIPTION THE DRAWING The FIGURE shows enclosure lcontaining substrate support2 equipped with heater 3 and shown as supporting substrates 4 which face in a downward direction. Auxiliary peripheral heater 5 helps to maintain a uniform temperature distribution in the vicinity of, the substrates. Perforated radiation shields 6 and 7 protect inlet manifold 8 from thermal radiation emanating from support 2 and substrates 4. Reactant gases 9 pass upward through the perforated-radiation shields 6 and 7 and diffuse upward across the essentially convectionfree vicinity of substrate 4. Residual product gases 10 diffuse across the vicinity of substrate 4 in a downward direction and leave the reactor.

Substrate support 2 is a stainless steel plate equipped with a cavity 21 which-is partly filled with sodium 22, evacuated, and sealed. Cavity 21 containsone or more piecesof wire mesh 23. in contact with the ceiling and the bottom of cavity 21. Under the influence of heat emanating from heater 3, sodium 22 liquefies, rises by capillary action along wire mesh 23 to the ceiling of cavity 21, evaporates, and condenses again at the bottom of cavity 21.

Operational Principles l The invention achieves uniformity of deposition through minimization of convection in the vicinity of the substrate. This minimization is accomplished by maintaining the substrate at an elevated temperature relative to the introduced reactant gases and by positioning it to face in a downward direction thus ensuring essentially planar and horizontal isotherms. Heating of the substrate may be accomplished by a variety of means, the key requirement being the uniformity of temperature at the surface ofthe substrate. One heater design which has been particularly effective in assuring uniform substrate temperature encompasses a so-called heat-pipel integral to the substrate support. In this design, a stainless steel plate supports the substrate and contains an evacuated and sealed cavity which is partly filled with a heat transfer medium such as liquid sodium.-Pieces-of,wire mesh are placed inside the cavity in contact with the' ceiling as:well as the bottom of the cavity to serve as a wick along which, through capillary action, the heat transfer medium reaches the top of the cavity. Alternately, steel wood, fiberglass, or an equiva- .lent 'could be used instead of wire mesh. The heat transfer medium evaporates at the heated ceiling of the cavity and condenses at the cooler lower end of the cavity, efficiently transferring heat in a downward direction.

Unless the width-to-height ratio of the zone between the radiation shield and the substrate is very large, peripheral heat and reactant losses should preferably be guarded against. In an experimental embodiment of the invention in which this ratio was about 6:1, peripheral heat loss was compensated by auxiliary heating from a heater tape wrapped around the reactor whose enclosure had a circular horizontal cross section. Depending on the application, differently shaped enclosures may be advantageous.

In order to prevent premature heating of the entering gases as they pass through the inlet manifold, a radiation shield is placed between the substrate and the inlet manifold. The shield protects the inlet manifold from thermal radiation emanating from the substrate and its support and helps prevent forced convection in the vicinity of the substrate. For this purpose the experimen tal embodiment utilizes a pair of gold plated fused quartz plates placed about 4 millimeters apart. The

plates are perforated and positioned relative to each other so that entering gases follow a tortuous rather then a straightthrough vertical path before reaching the vicinity of the substrate. While the experimental embodiment utilizes a pair of plates as a radiation shield, the use of only one or of more than two such plates is not precluded.

During deposition, reactant gases diffuse upward from the radiation shield. At the surface of the substrate reactants are consumed and products created by the deposition reaction. The residual gaseous products in turn diffuse downward and away from the vicinity of the substrate through the radiation shields. The inlet manifold, located in the convection zone below the radiation shields, supplies fresh gases, preferably in a uniform, periodic array ofjets to the underside of the radiation shields. The incoming gases dilute the product gases which are forced out the bottom of the reactor; typical gas flow and deposition rates are shown in the examples below.

EXAMPLE 1 Silicon dioxide was deposited onto silicon and tungsten metallized silicon at a temperature of 720C according to the chemical reaction Sil-l, 2N O SiO 2H, N,

using helium as a carrier gas. Flow rates were 1.5 cm lmin for Sil-l 187.5 cm lmin for N 0, and 91 cm /min for helium. Under these conditions a deposition rate of 0.8 micrometers per hour was realized.

' Variation in thickness of the deposited layer, measured with a spectrophotometer, was found to be no more than 4 percent over the 1% inch diameter silicon wafers. This compares favorably with variation of up to percent resulting from the use of commercially available apparatus.

EXAMPLE 2 Silicon nitride was deposited onto stainless steel at a temperature of 720C according to the chemical reaction using helium as a carrier gas. Flow rates were 1.5

cm /min for SiH cm lmin for NH and 91 cmlmin for helium. A deposition rate of 1.2 micrometers per hour was achieved.

What is claimed is:

1. Chemical vapor deposition apparatus for depositing a layer of a substance on a surface of a substrate comprising means for supporting said substrate,

means for introducing at least one gas producing said substance into a zone adjacent to said surface,

means for extracting any residual gaseous material,

and

means for uniformly maintaining said substrate at a temperature higher than that of said introduced gas characterized in that 1. said surface generally defines the upper extremityof said zone,

2. said surface faces in a downward direction,

3. the lower extremity of said zone is-generally defined by a radiation shield permeable to reactant, carrier and product gases, and

4. means are provided for introducing said gas at a position below said radiation shield.

2. Chemical vapor deposition apparatus of claim 1 in which said radiation shield consists of at least one perforated plate in a position essentially parallel to said surface of said substrate and of which at least the plate closest to said surface is equipped with a heat-reflecting coating.

'3. Chemical vapor deposition apparatus of claim 2 in which said radiation shield consists of a pair of plates separated by a distance of 0.140 centimeters.

4. Chemical vapor deposition apparatus of claim 1 equipped with an auxiliary heated positioned at the periphery of the zone between the substrate and the radiat ion shield.

5. Chemical vapor deposition apparatus of claim 1 in which said supporting means is a heated plate.

6. Chemical vapor deposition apparatus of claim 5 in which said plate is equipped with a heat pipe for transfer'ring heat from the upper to the lower extremity of said plate.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3015586 *Jan 15, 1958Jan 2, 1962IttMethod of making charge storage electrodes for charge storage tubes
US3117025 *Aug 31, 1961Jan 7, 1964Space Technology Lab IncThin filming apparatus
US3206325 *Sep 14, 1961Sep 14, 1965Alloyd CorpProcess for producing magnetic product
US3446906 *May 17, 1967May 27, 1969Tektronix IncResilient conductive coated foam member and electromagnetic shield employing same
US3517643 *Nov 25, 1968Jun 30, 1970Sylvania Electric ProdVapor deposition apparatus including diffuser means
US3677329 *Nov 16, 1970Jul 18, 1972Trw IncAnnular heat pipe
US3690635 *May 16, 1969Sep 12, 1972Air ReductionCondensate collection means
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4055217 *Feb 2, 1976Oct 25, 1977Western Electric Company, Inc.Method for maintaining a vapor blanket in a condensation heating facility
US4653428 *May 10, 1985Mar 31, 1987General Electric CompanySelective chemical vapor deposition apparatus
US4709655 *Dec 3, 1985Dec 1, 1987Varian Associates, Inc.Chemical vapor deposition apparatus
US4798165 *Jan 25, 1988Jan 17, 1989EpsilonApparatus for chemical vapor deposition using an axially symmetric gas flow
US4842686 *Jul 17, 1987Jun 27, 1989Texas Instruments IncorporatedWafer processing apparatus and method
US4886570 *Dec 2, 1988Dec 12, 1989Texas Instruments IncorporatedProcessing apparatus and method
US4997677 *Aug 31, 1987Mar 5, 1991Massachusetts Institute Of TechnologyVapor phase reactor for making multilayer structures
US5118642 *Jan 24, 1991Jun 2, 1992Daidousanso Co., Ltd.Method for producing semiconductors
US5138973 *Dec 5, 1988Aug 18, 1992Texas Instruments IncorporatedWafer processing apparatus having independently controllable energy sources
US5156820 *May 15, 1989Oct 20, 1992Rapro Technology, Inc.Reaction chamber with controlled radiant energy heating and distributed reactant flow
US5444217 *Jan 21, 1993Aug 22, 1995Moore Epitaxial Inc.Rapid thermal processing apparatus for processing semiconductor wafers
US5458689 *Feb 3, 1995Oct 17, 1995Fujitsu LimitedApparatus and method for growing semiconductor crystal
US5580388 *May 30, 1995Dec 3, 1996Moore Epitaxial, Inc.Multi-layer susceptor for rapid thermal process reactors
US5647911 *Dec 14, 1993Jul 15, 1997Sony CorporationGas diffuser plate assembly and RF electrode
US5683518 *Jan 21, 1994Nov 4, 1997Moore Epitaxial, Inc.Rapid thermal processing apparatus for processing semiconductor wafers
US5710407 *Jun 7, 1995Jan 20, 1998Moore Epitaxial, Inc.Rapid thermal processing apparatus for processing semiconductor wafers
US5772757 *Jun 7, 1995Jun 30, 1998Fujitsu LimitedApparatus and method for growing semiconductor crystal
US5908508 *May 30, 1995Jun 1, 1999Tokyo Electron LimitedGas diffuser plate assembly and RF electrode
US6002109 *Jul 10, 1995Dec 14, 1999Mattson Technology, Inc.System and method for thermal processing of a semiconductor substrate
US6132512 *Jan 8, 1998Oct 17, 2000Ebara CorporationVapor-phase film growth apparatus and gas ejection head
US6151447 *Nov 25, 1997Nov 21, 2000Moore TechnologiesRapid thermal processing apparatus for processing semiconductor wafers
US6310327Aug 18, 2000Oct 30, 2001Moore Epitaxial Inc.Rapid thermal processing apparatus for processing semiconductor wafers
US6403925Oct 25, 2000Jun 11, 2002Mattson Technology, Inc.System and method for thermal processing of a semiconductor substrate
US7387811 *Sep 21, 2004Jun 17, 2008Superpower, Inc.Method for manufacturing high temperature superconducting conductors using chemical vapor deposition (CVD)
US8133322Sep 27, 2002Mar 13, 2012Cree, Inc.Apparatus for inverted multi-wafer MOCVD fabrication
US20040060518 *Sep 27, 2002Apr 1, 2004Cree Lighting CompanyApparatus for inverted multi-wafer MOCVD fabrication
US20060062900 *Sep 21, 2004Mar 23, 2006Venkat SelvamanickamChemical vapor deposition (CVD) apparatus usable in the manufacture of superconducting conductors
US20060141414 *Feb 27, 2006Jun 29, 2006Mitsubishi Heavy Industries, Ltd.Gas combustion treatment method and apparatus therefor
US20060188658 *Feb 21, 2006Aug 24, 2006Grant Robert WPressurized reactor for thin film deposition
US20090186194 *Apr 25, 2008Jul 23, 2009Nanoscale Components, Inc.Batch Process for Coating Nanoscale Features and Devices Manufactured From Same
US20110159214 *Mar 26, 2009Jun 30, 2011Gt Solar, IncorporatedGold-coated polysilicon reactor system and method
DE19622403C1 *Jun 4, 1996Nov 20, 1997Siemens AgVorrichtung zum Erzeugen einer Schicht auf der Oberfläche wenigstens eines Substrats durch CVD
EP0276061A1 *Jan 8, 1988Jul 27, 1988Varian Associates, Inc.Rapid thermal chemical vapour deposition apparatus
EP0299243A1 *Jun 23, 1988Jan 18, 1989Texas Instruments IncorporatedProcessing apparatus and method
EP0299244A1 *Jun 23, 1988Jan 18, 1989Texas Instruments IncorporatedProcessing apparatus and method
EP0299246A1 *Jun 23, 1988Jan 18, 1989Texas Instruments IncorporatedProcessing apparatus and method
EP0300217A2 *Jun 23, 1988Jan 25, 1989Texas Instruments IncorporatedProcessing apparatus and method
EP0319122A1 *Aug 8, 1988Jun 7, 1989Daidousanso Co., Ltd.Apparatus and its use for producing semiconductors
EP0396239A2 *Mar 16, 1990Nov 7, 1990Daidousanso Co., Ltd.Apparatus for producing semiconductors by vapour phase deposition
EP0848223A1 *Aug 30, 1996Jun 17, 1998Nippon Pillar Packing Co., Ltd.Vertical heat treatment device
EP0853138A1 *Jan 8, 1998Jul 15, 1998Ebara CorporationVapor-phase film growth apparatus and gas ejection head
EP1143034A1 *Mar 31, 2001Oct 10, 2001Angewandte Solarenergie - ASE GmbHMethod and apparatus for coating or treatment of a substrate
WO1986006755A1 *May 9, 1986Nov 20, 1986General Electric CompanySelective chemical vapor deposition method and apparatus
WO1995016804A1 *Nov 22, 1994Jun 22, 1995Materials Research CorporationGas diffuser plate assembly and rf electrode
Classifications
U.S. Classification118/725, 165/104.26
International ClassificationC23C16/46, C23C16/455, C23C16/44
Cooperative ClassificationC23C16/46, C23C16/45565, C23C16/45559, C23C16/455
European ClassificationC23C16/455H, C23C16/46, C23C16/455, C23C16/455K2