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
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/56—Apparatus specially adapted for continuous coating; Arrangements for maintaining the vacuum, e.g. vacuum locks
  • C23C14/564—Means for minimising impurities in the coating chamber such as dust, moisture, residual gases
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
  • H01J37/317—Electron-beam or ion-beam tubes for localised treatment of objects for changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation
  • H01J37/3171—Electron-beam or ion-beam tubes for localised treatment of objects for changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation for ion implantation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/02—Details
  • H01J2237/022—Avoiding or removing foreign or contaminating particles, debris or deposits on sample or tube

Definitions

• An ion i planti ng apparatus or ion implanter basically comprises a beam line section for generating ions and selecting a desired ion species to yield an ion beam, and an ion implantation section for irradiating a silicon wafer with the ion beam from the beam line section and carrying out ion implantation.
• ion implanter When an ion implantation process is carried out in thus configured ion implanter, its ions are implanted not only into the wafer but also into a beam stop disposed in the target chamber after passing through the space between the wafer and the target.
• the ions are also implanted into part of the wafer support wheel such as tip portions of arms and inner wall faces of the target chamber in particular.
• the ions thus implanted into the parts other than the wafer may cause so-called cross contamination. For example, there is a case where, after carrying out several cycles of phosphorus implantation process, the same ion implanter is used for an arsenic ion implantation process.
• Another aspect of the present invention is directed to an ion implanting apparatus comprising abeam line section for forming and emitting an ion beam, a target chamber in which a substrate is disposed and ion implantation to said substrate is effected by said ion beam emitted therein from said beam line section, first evacuating means for evacuating said beam line section, second evacuating means for evacuating said target chamber, and oxygen gas supply means for supplying an oxygen gas into said target chamber.
• Fig. 4 is a graph showing results of experiments of the cleaning method in accordance with the present invention carried out with various cleaning times, in which influences on the subsequent arsenic implantation process are indicated in terms of sheet resistance and its shifting ratio.
• the ion supply system 18 is adapted to produce a high-density plasma state by discharging a doping gas fed from a gas supply (not shown).
• the ion beam extracting/pre-accelerating system 20 extracts and accelerates ions constituting the plasma, thereby forming an ion beam IB.
• the mass analyzing system 22 includes an analyzing magnet (not shown) disposed therein, and is adapted to extract only a desired ion species from the ion beam IB by adjusting the strength of magnetic field.
• the ion beam IB passed through the mass analyzing system 22 is further accelerated by the post-accelerating system 24, so as to be adjusted to a speed suitable for ion implantation.
• the ion implantation sectio n 14 comprises a box-type target chamber 30 and a wafer support wheel 32 disposed within the target chamber 30.
• the wafer loader section 16 is disposed close to the target chamber 30.
• the housing 54 of the wafer loader section 16 and the target chamber 30 are communicated with each other via a transportation path 56.
• an isolation valve 58 is inserted, so as to make the housing 54 and the target chamber 30 separable from each other. Therefore, the wafer loader section 16 can be made open to the atmosphere alone, whereby the operator can place a cassette (not shown) accommodating therein a plurality of wafers W into the housing 54.
• the wafers W in the cassette can be transported by a robot (not shown), such as to be mounted to the respective wafer holders 52 of the wafer support wheel 32 within the target chamber 30.
• the ion implanter 10 in accordance with the present invention further comprises an oxygen gas supply 60.
• the oxygen gas supply 60 communicates with the inside of the target chamber 30 via a pipe 62.
• the position at which the pipe 62 is connected to the target chamber 30, i.e., the position of the oxygen gas inlet 64 can be defined as appropriate, it is preferably located in the vicinity of the irradiation path of the ion beam IB.
• dummy wafers are transported from another cassette disposed within the housing 54 into the target chamber 30, so as to be mounted to all the wafer holders 52 of the wafer support wheel 32, respectively. Then, the isolation valve 58 is closed. During these operations, the target chamber 30 is not open to the atmosphere and keeps a vacuum therein.
• the ion implantation process subsequent to the cleaning process is an arsenic implantation process in the above-mentioned embodiment, this process may implant impurities other than arsenic.
• the phosphorus implantation process may be continued.
• the cleaning process in accordance with the present invention can overcome, for example, such problems as shifting sheet resistance.
• argon, antimony, and the like are suitable as the ion species of ion beams.
• antimony and argon are naturally implanted into the inner wall faces of the target chamber and the like, cross contamination of these elements are not considered to effect the current semiconductor manufacturing process adversely.

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• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physical Vapour Deposition (AREA)

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Cited By (5)

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Citations (2)

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• 1997
  • 1997-12-16 JP JP34656797A patent/JP4088362B2/ja not_active Expired - Fee Related
• 1998
  • 1998-12-16 WO PCT/GB1998/003776 patent/WO1999031712A1/en active Application Filing

Patent Citations (2)

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