Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/42—Silicides
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D64/00—Electrodes of devices having potential barriers
  • H10D64/01—Manufacture or treatment
  • H10D64/011—Manufacture or treatment of electrodes ohmically coupled to a semiconductor
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D64/00—Electrodes of devices having potential barriers
  • H10D64/01—Manufacture or treatment
  • H10D64/011—Manufacture or treatment of electrodes ohmically coupled to a semiconductor
  • H10D64/0111—Manufacture or treatment of electrodes ohmically coupled to a semiconductor to Group IV semiconductors
  • H10D64/0112—Manufacture or treatment of electrodes ohmically coupled to a semiconductor to Group IV semiconductors using conductive layers comprising silicides
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/40—Formation of materials, e.g. in the shape of layers or pillars of conductive or resistive materials
  • H10P14/412—Deposition of metallic or metal-silicide materials
  • H10P14/414—Deposition of metallic or metal-silicide materials of metal-silicide materials
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S148/00—Metal treatment
  • Y10S148/147—Silicides

Definitions

• the invention relates to the manufacture of semiconductor wafers using chemical vapor deposition (CVD) of tungsten silicide and, in particular, to a process for depositing tungsten silicide by the reduction of tungsten hexafluoride (WF 6 ) by silane gases.
• CVD chemical vapor deposition
• refractory metal suicides such as tungsten silicide
• tungsten silicide have received increasing use in the manufacture of semiconductor integrated circuits, e.g. as Schottky barriers, ohmic contacts, or gate metallizations.
• a low resistivity tungsten silicide layer is formed on a polysilicon layer. Due to the ever decreasing geometry of devices in an integrated circuit, uniformity of the deposition is of great concern. Similarly, deposition rate is of concern since it determines production rates.
• a high silicon to tungsten ratio i.e. greater than 2.6:1 prevents degradation of the silicide film in subsequent steps and poor adhesion to the underlying polysilicon film.
• a silicon to tungsten ratio greater than 2.6:1 is desirable to suppress oxidation of the tungsten in the silicide film and to control consumption of the underlying polysilicon film during formation of the Si0 2 dielectric.
• the excess silicon in the silicide film also reduces film stress and provides for more desirable etching characteristics.
• the ratio could be increased only by decreasing the partial pressure of the F 6 (or increasing the partial pressure of SiH 4 /SiH 2 Cl 2 /Si 2 H 6 ) . This leads to lower deposition rates and worse uniformity.
• One technique for modifying the silicon to tungsten ratio is to deposit a thin layer of silicon prior to depositing the silicide, as described in U.S. Patent 4,737,474. While this provides greater adhesion, it does not modify the silicon content of the bulk of the silicide layer.
• Another object of the present invention is to provide a process for controlling the silicon to tungsten ratio independently of deposition rate and uniformit .
• a further object of the present invention is to provide a silicon to tungsten ratio of 2.6:1 or greater.
• the silicon to tungsten ratio in a tungsten silicide film can be significantly increased by adding less than ten percent disilane (Si 2 H 6 ) to the gas mixture of WF 6 and SiH 2 Cl 2 ; i.e. disilane is added to the mixture rather than replacing another gas, as in the prior art. As more fully described herein, it has been discovered that this addition provides significantly improved and unexpected results.
• FIG. 1 illustrates the present invention in terms of the effect of the flow of WF 6 on film resistivity.
• FIG. 2 illustrates the present invention in terms of the effect of the flow of WF 6 on film uniformity.
• FIG. 3 illustrates the present invention in terms of the effect of the flow of WF 6 on film deposition rate.
• the abscissa represents the rate of flow of WF 6 in SCCM.
• Value labels 11 and 12 indicate the WF 6 flow without and with disilane, respectively.
• the ordinate in FIG. 1 represents resistivity.
• Line 10 indicates the result of using a combination of SiH 2 Cl 2 and WF 6 only.
• Line 20 indicates the result of adding disilane to the mixture. Clearly, adding disilane reduces the effect of increasing the flow of WF 6 .
• the ordinate represents uniformity, expressed as a percent.
• Line 13 shows the typical relationship obtained in the prior art without the addition of disilane.
• Line 23 shows the effect of adding disilane. Unexpectedly and unpredictably, the slope of the line is reversed from that of line 13.
• Films produced as above were annealed at a temperature of 1050°C for 180 seconds.
• the resistivity dropped to 60 ⁇ -cm.
• Films which were oxidized showed very uniform Si0 2 growth without oxidation of tungsten.
• the partial pressure of Si 2 H 6 is varied.
• the wafer temperature is 560°C and the pressure is 90 mtorr.
• wafer temperature can vary from 450°C to 650°C, the higher temperatures increasing deposition rate.
• Suitable pressures are from 30 to 300 mtorr.
• the partial pressure of dichlorosilane can vary from 27 to 285 mtorr, with corresponding adjustments in the partial pressures of WF 6 and disilane.
• the amount of disilane added can comprise up to ten percent of the gas mixture.

Landscapes

• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
• Chemical Vapour Deposition (AREA)
• Electrodes Of Semiconductors (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=24068739

Family Applications (1)

Country Status (6)

Families Citing this family (22)

Citations (4)

Family Cites Families (1)

• 1990
  • 1990-05-04 US US07/519,538 patent/US4966869A/en not_active Expired - Fee Related
• 1991
  • 1991-05-03 DE DE19914190885 patent/DE4190885T/de not_active Withdrawn
  • 1991-05-03 JP JP3508911A patent/JPH05504660A/ja active Pending
  • 1991-05-03 NL NL9120003A patent/NL9120003A/nl not_active Application Discontinuation
  • 1991-05-03 KR KR1019910702017A patent/KR920702794A/ko not_active Withdrawn
  • 1991-05-03 WO PCT/US1991/003049 patent/WO1991017566A1/en not_active Ceased

Patent Citations (4)

Also Published As

Similar Documents

Legal Events