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
  • C23C16/44—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 method of coating
  • C23C16/458—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 method of coating characterised by the method used for supporting substrates in the reaction chamber
  • C23C16/4582—Rigid and flat substrates, e.g. plates or discs
  • C23C16/4583—Rigid and flat substrates, e.g. plates or discs the substrate being supported substantially horizontally
• • 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
  • C23C16/44—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 method of coating
  • C23C16/50—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 method of coating using electric discharges
  • C23C16/505—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 method of coating using electric discharges using radio frequency discharges
  • C23C16/509—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 method of coating using electric discharges using radio frequency discharges using internal electrodes
  • C23C16/5096—Flat-bed apparatus

Definitions

• a method for depositing layers on a substrate is a method for depositing layers on a substrate.
• the present invention relates to a method for depositing layers, e.g. by Plasma Enhanced Chemical Vapour Deposition (PECVD), on a substrate, said method comprising placing the substrate between a top electrode and a bottom electrode
• PECVD Plasma Enhanced Chemical Vapour Deposition
• An advantage of the chemical cleaning process is that it is performed without taking the system apart thus reducing down time of the chamber.
• the process suffers from a problem of different etch rates on different surfaces.
• the etch rate on the live electrode is approximately a factor of two higher than on the grounded electrode.
• the aluminium walls of the chamber will be subjected to the plasma when all deposited glass has been removed. Continuing the cleaning process after this will result in a build-up of a polymer layer. As the cleaning process will not stop before the grounded electrode is cleaned, a fairly thick layer of polymers will be formed on the live electrode.
• a polymer layer will also be formed immediately on the grounded electrode in the place where the wafer has been lying since no glass is deposited here. After the cleaning process the chamber is therefore partly clean, partly covered by polymers. These polymers will affect the deposition process in a number of ways.
• the deposited glass tends to peel off the polymer layers after a certain time giving rise to particle contamination in the chamber. This will affect the film quality.
• the layer thickness of the polymers on the grounded electrode is not necessarily the same from time to time. Therefore the environment for the wafers will not be the same between different depositions and cleaning cycles. Using different substrate sizes will also not be possible, e.g. deposition on a 5" wafer after a 4" wafer will result in a different surrounding at the outer part of the 5" wafer as compared to the center 4" part. In conclusion two problems need to be solved:
• the cleaning process should be as short as possible to increase the system up time.
• UK patent application GB 2312439 discloses a method for deposition of layers by PECVD for the fabrication of optical waveguides. It is disclosed that higher repeatability and control of the refractive index is obtained by placing the substrate on the live electrode and thus maintaining a negative bias on the substrate during deposition. None is disclosed about how to prevent un-wanted build-up of layers of deposited material on the electrodes, cleaning procedures, how to prevent build up of polymers during cleaning or generally about how to increase chamber up-time and stable chamber conditions. Disclosure of the invention.
• This method is characterised in that the substrate is placed on a carrier that is placed on the bottom electrode.
• the carrier constitutes of 2 parts, namely an outer carrier with a hole, and an inner carrier so dimensioned, that it fits in the hole, it is possible to remove the substrate without removing the carrier, fx. by first lifting the inner carrier and then remove the substrate.
• the inner carrier has an area that is less than the area of the substrate.
• Fig. 1 illustrates a principle structure of the interior parts of a horizontal parallel plate PECVD chamber
• Fig. 2 illustrates an embodiment of the carrier.
• a horizontal parallel plate PECVD chamber with bottom and top electrode are designated 1 ,2 respectively.
• a substrate 4 is placed on a carrier plate 3, such as a large fused silica carrier 3.
• the diameter of the fused silica carrier 3 should match the diameter of the bottom electrode 1 to keep it free from unwanted deposited material. Stops 5 keep the substrate 4 in its designated position on the carrier plate 3 during loading and un-loading and during processing.
• the impedance of the system will be less affected by the deposited material.
• Deposition on different substrate 4 sizes can be done either by using the same fused silica carrier 3 or another carrier 3.
• the cleaning process is carried out with a fused silica carrier 3.
• the cleaning process is then stopped as soon as the live electrode 2 has been cleaned. This way polymer formation is almost completely avoided.
• Fig. 2 shows a carrier that differs from the carrier in fig. 1 in that the carrier constitutes of 2 parts, namely an outer carrier 6 with a hole 7, and an inner carrier 8 dimensioned in such a way that it fits to the hole 7 of the outer carrier.
• the inner carrier has a diameter or an area slightly less than the substrate processed.
• the most notable advantage of this method is the increased up time of the PECVD deposition system.
• Manufacturers of PECVD equipment recommend a plasma clean for every 5-6 ⁇ m of deposited material. This would render thick layer (4-15 ⁇ m) fabrication impossible. Further, the recommended cleaning time is similar to the deposition time.
• a further advantage is improved reproducibility.
• the deposited material behaves much like the fused silica carrier 3 and therefore the plasma environment will not change during depositions.
• the polymer formation in the chamber is also dramatically reduced. This provides for considerably better glass quality than with conventional techniques.
• both the dielectric and thermal properties of the carrier material should be similar to the dielectric and thermal properties of the material deposited in the
• silica or doped silica is deposited, a fused silica carrier is preferred.
• the carrier is equipped with some means of holding the wafer in place when the wafer-on-carrier is loaded into or out of the PECVD chamber and during processing.
• the wafer positioning means consist of a recess in the carrier that fits the wafer.
• stops are placed on the carrier to hold the wafer in place.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Drying Of Semiconductors (AREA)
• Chemical Vapour Deposition (AREA)
• Optical Integrated Circuits (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

Country Status (4)

Family Cites Families (7)

• 1999
  • 1999-11-15 DK DK199901642A patent/DK173655B1/da not_active IP Right Cessation
• 2000
  • 2000-11-15 WO PCT/DK2000/000634 patent/WO2001036708A1/en not_active Application Discontinuation
  • 2000-11-15 EP EP00975836A patent/EP1248866A1/en not_active Withdrawn
  • 2000-11-15 AU AU13822/01A patent/AU1382201A/en not_active Abandoned

Non-Patent Citations (1)

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