Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02041—Cleaning
  • H01L21/02043—Cleaning before device manufacture, i.e. Begin-Of-Line process
  • H01L21/02052—Wet cleaning only
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
  • C30B29/02—Elements
  • C30B29/06—Silicon
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
  • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
  • H01L21/0223—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate
  • H01L21/02233—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer
  • H01L21/02236—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor
  • H01L21/02238—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor silicon in uncombined form, i.e. pure silicon
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
  • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting

Definitions

• the present invention relates to a method for cleaning a silicon wafer.
• RCA cleaning is a cleaning method in which SC1 (Standard Cleaning 1) cleaning, SC2 (Standard Cleaning 2) cleaning, and DHF (Diluted Hydrofluoric Acid) cleaning are combined in accordance with the purpose.
• SC1 cleaning ammonia water and hydrogen peroxide water are mixed at an arbitrary ratio, and the adhered particles are lifted off by etching the surface of the silicon wafer with an alkaline cleaning liquid.
• SC2 cleaning is a cleaning method in which metal impurities on the surface of a silicon wafer are dissolved and removed with a cleaning liquid in which hydrochloric acid and hydrogen peroxide water are mixed at an arbitrary ratio.
• the DHF cleaning is a cleaning method for removing the chemical oxide film on the silicon wafer surface with dilute hydrofluoric acid.
• ozone water cleaning having a strong oxidizing power may be used, and organic substances adhering to the silicon wafer surface are removed and a chemical oxide film is formed on the silicon wafer surface after DHF cleaning. Cleaning of silicon wafers is performed by combining these cleanings according to the purpose (Patent Documents 1 to 3).
• JP 2002-329691 A Japanese Patent Laid-Open No. 9-017765 JP-A-9-260328 JP 2006-208314 A
• DSOD Direct Surface Oxide Defect
• the quality evaluated by this DSOD evaluation is affected by silicon wafer surface defects, crystal defects, metal contamination, the quality of chemical oxide films formed in the cleaning process, and the like. For this reason, even when the clear cause is unknown, the DSOD quality may be deteriorated or fluctuate. Therefore, in order to improve the DSOD quality, it is necessary to improve the surface defects and crystal defects and stabilize the quality of the chemical oxide film formed in the cleaning process.
• the chemical oxide film formed in the SC1 cleaning process is very thin.
• the chemical oxide film thickness after SC1 cleaning is measured to be about 0.7 nm by XPS (X-ray photoelectron spectroscopy).
• the chemical oxide film thickness formed by this SC1 cleaning does not change even if the cleaning time and the temperature of the cleaning liquid are changed within a realistic time in the manufacture of the silicon wafer, and the chemical oxide film thickness is controlled under the SC1 cleaning conditions. I can't do that.
• the present invention is a silicon wafer cleaning method in which a silicon wafer is SC1 cleaned and then cleaned with a cleaning solution having an oxidizing power, and is formed on the surface of the silicon wafer by the SC1 cleaning.
• a silicon wafer cleaning method wherein a chemical oxide film is grown with a cleaning liquid having an oxidizing power so that the thickness of the chemical oxide film is 1.0 nm or more.
• the chemical oxide film formed on the surface of the silicon wafer can be formed to be 1.0 nm or more thicker than before, and the silicon wafer surface quality can be improved. It becomes.
• ozone water and / or hydrogen peroxide water as the cleaning liquid having the oxidizing power.
• the silicon wafer cleaning method of the present invention is particularly effective in such a case.
• Such a silicon wafer cleaning method can further improve the silicon wafer surface quality by dissolving and removing metal impurities on the silicon wafer surface.
• the silicon wafer to be cleaned by SC1 is a silicon wafer that has not been DHF cleaned.
• the chemical oxide film is not removed in advance, so that a sufficient chemical oxide film thickness can be obtained and the surface quality of the silicon wafer can be improved more reliably. It becomes.
• the chemical oxide film formed on the surface of the silicon wafer can be formed to be 1.0 nm or more thicker than before, and the surface quality of the silicon wafer can be stably improved. It becomes possible.
• the present inventors performed chemical oxidation with a cleaning solution having oxidizing power after the cleaning flow for performing SC2 cleaning after SC1 cleaning or SC1 cleaning, and this chemical oxidation.
• the chemical oxide film thickness can be grown to 1.0 nm, and the surface quality of the silicon wafer can be stabilized and improved, and the present invention has been achieved.
• the present invention is a silicon wafer cleaning method of cleaning a silicon wafer with SC1 and then cleaning with a cleaning solution having an oxidizing power, wherein the chemical oxide film formed on the surface of the silicon wafer by the SC1 cleaning is
• a silicon wafer cleaning method characterized in that the chemical oxide film is further grown to a thickness of 1.0 nm or more by cleaning with a cleaning solution having an oxidizing power.
• the chemical oxide film formed on the surface of the silicon wafer can be formed and stabilized with a thickness of 1.0 nm or more, and the silicon wafer surface quality can be improved. Is possible.
• the silicon wafer is first cleaned SC1.
• the adhered particles are lifted off by etching the surface of the silicon wafer with an alkaline cleaning liquid, and the particles are removed while suppressing re-adhesion to the silicon wafer by utilizing electrostatic repulsion between the silicon wafer and the particles.
• a thin chemical oxide film is formed on the surface of the silicon wafer by SC1 cleaning.
• the silicon wafer cleaned with SC1 is cleaned with a cleaning solution having an oxidizing power to perform chemical oxidation.
• the chemical oxide film is cleaned with a cleaning solution having an oxidizing power so that the thickness of the chemical oxide film is 1.0 nm or more (preferably 1.2 nm or less).
• ozone water and / or hydrogen peroxide water as the cleaning liquid having the oxidizing power.
• the present invention is particularly effective when such a cleaning liquid is used.
• the ozone concentration is preferably 10 ppm or more. If the ozone water concentration is larger than 10 ppm, the oxidation in the silicon wafer surface becomes uniform, which is preferable.
• the SC2 cleaning can be performed before the cleaning with the oxidizing power.
• a silicon wafer cleaning method it is possible to further improve the quality of the silicon wafer surface by dissolving and removing metal impurities on the surface of the silicon wafer.
• the silicon wafer to be cleaned by SC1 is a silicon wafer that has not been DHF cleaned.
• a silicon wafer cleaning method With such a silicon wafer cleaning method, a chemical oxide film having a sufficient thickness can be obtained without removing the chemical oxide film previously formed on the surface of the silicon wafer. It becomes possible to improve the surface quality.
• a silicon wafer for evaluation was prepared.
• a 300 mm silicon wafer that was clean and had no crystal defects called COP or DSOD after mirror polishing was prepared.
• COP is a crystal-induced pit-like defect that is detected on the surface of a silicon wafer after the mirror-polished silicon wafer is cleaned with a mixed solution of ammonia water and hydrogen peroxide water called SC1 cleaning. This pit-like defect is detected together with the particles by measuring the surface of the silicon wafer with a particle counter.
• COP causes deterioration of TDDB (Time Dependent Dielectric Breakdown) and TZDB (Time Zero Dielectric Breakdown) in GOI (Gate Oxide Integrity) evaluation, which is performed as reliability evaluation of an oxide film.
• DSOD defects are detected by DSOD evaluation by the Cu deposition method. Three silicon wafers for evaluation were used, two of which were used for DSOD evaluation, and the other one was used for chemical oxide film thickness evaluation by XPS.
• a cleaning solution having HF of 3.0 wt% was used.
• the concentration of the chemical used for adjusting the mixed solution was 28 wt% for NH 4 OH and 30 wt% for H 2 O 2 .
• DSOD evaluation Chemical oxide film evaluation of the cleaned silicon wafer was performed by DSOD evaluation by a Cu deposition method.
• the DSOD evaluation by the Cu deposition method is described in Patent Document 4 and is performed as follows.
• a chemical oxide film oxide insulating film
• the oxide insulating film on the defective portion formed on the surface layer of the silicon wafer is destroyed.
• Cu is deposited (deposited) on the broken oxide film portion to identify the defect.
• the DSOD can also detect process abnormalities such as scratches and metal contamination that affect the surface quality of the silicon wafer, such as polishing and cleaning.
• XPS is a technique for analyzing the composition and chemical bonding state of elements constituting a sample surface by irradiating the sample surface with X-rays and measuring the kinetic energy of photoelectrons emitted from the sample surface.
• the chemical oxide film thickness in Comparative Example 1 was 0.7 nm, and the number of DSODs was 31, 36 for the two DSOD evaluated, respectively.
• the chemical oxide film thickness in Comparative Example 2 was 0.7 nm, and the number of DSODs was 34 and 39 for the two DSOD evaluated, respectively.
• Comparative Example 3 The cleaning of the silicon wafer was performed in the same manner as Comparative Example 1 except that the SC2 cleaning was performed after the SC1 cleaning.
• HCl hydrochloric acid
• the chemical oxide film thickness in Comparative Example 3 was 0.7 nm, and the number of DSODs was 29 and 35 for the two DSOD evaluated, respectively.
• the chemical oxide film thickness in Comparative Example 4 was 0.7 nm, and the number of DSODs was 31, 33 for the two DSOD evaluated, respectively.
• Comparative Example 5 The cleaning of the silicon wafer was performed in the same manner as in Comparative Example 1 except that a cleaning liquid having a HF of 1.0 wt% was used in the DHF cleaning.
• the chemical oxide film thickness in Comparative Example 5 was 0.7 nm, and the number of DSODs was 35 and 40 for the two DSOD evaluated, respectively.
• Example 1 The silicon wafer was cleaned in the same manner as in Comparative Example 1 except that cleaning with ozone water was performed after SC1 cleaning.
• the chemical oxide film thickness in Example 1 was 1.0 nm, and the number of DSODs was 13 and 16 for the two DSOD evaluated, respectively.
• the chemical oxide film thickness in Example 2 was 1.0 nm, and the number of DSODs was 11 and 17 for the two DSOD evaluated, respectively.
• Example 3 The cleaning of the silicon wafer was performed in the same manner as in Example 2 except that the cleaning time with ozone water was 1 min.
• the chemical oxide film thickness in Example 3 was 1.0 nm, and the number of DSODs was 15 and 17 for the two DSOD evaluated, respectively.
• Example 4 The cleaning of the silicon wafer was performed in the same manner as in Example 1 except that the SC2 cleaning was performed after the SC1 cleaning and before the cleaning with ozone water. SC2 cleaning was performed in the same manner as in Comparative Example 3.
• the chemical oxide film thickness in Example 4 was 1.0 nm, and the number of DSODs was 16 and 18 for the two DSOD evaluated, respectively.
• the chemical oxide film thickness in Example 6 was 1.0 nm, and the number of DSODs was 13 and 15 for the two DSOD evaluated, respectively.
• Example 7 The cleaning of the silicon wafer was performed in the same manner as in Example 5 except that SC2 cleaning was performed after SC1 cleaning and before cleaning with hydrogen peroxide solution, and cleaning with hydrogen peroxide solution was performed at 60 ° C. SC2 cleaning was performed in the same manner as in Comparative Example 3.
• the chemical oxide film thickness in Example 7 was 1.0 nm, and the number of DSODs was 12 and 16 for the two DSOD evaluated, respectively.
• the chemical oxide film thickness was 0.7 nm, and in Examples 1 to 7, the chemical oxide film thickness was 1.0 nm.
• the chemical oxide film thickness of the comparative example is 0.7 nm, while the chemical oxide film thickness of the comparative example is 1.0 nm, which is thicker than the comparative example.
• the SC1 cleaning is an equilibrium reaction between oxidation and etching, it is presumed that the SC1 cleaning has reached an equilibrium state before the chemical oxide film is saturated.
• the chemical oxide film formed by the SC1 cleaning is further oxidized with a cleaning liquid having an oxidizing power (ozone water, hydrogen peroxide solution), so that the chemical oxide film thickness is increased to 1.0 nm. I guess it was possible. It should be noted that it is difficult to increase the thickness of the chemical oxide film within a practical time in the production of a silicon wafer.
• the number of DSODs measured by DSOD evaluation in Examples is about half to less than half of the number of DSODs measured by DSOD evaluation in Comparative Examples. It can be greatly reduced, and it has become possible to suppress the deterioration of silicon wafer quality due to cleaning.
• the present invention is not limited to the above embodiment.
• the above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

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• Engineering & Computer Science (AREA)
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• Crystallography & Structural Chemistry (AREA)
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• Condensed Matter Physics & Semiconductors (AREA)
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• Computer Hardware Design (AREA)
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• Cleaning Or Drying Semiconductors (AREA)
• Crystals, And After-Treatments Of Crystals (AREA)
• Detergent Compositions (AREA)
• Mechanical Treatment Of Semiconductor (AREA)

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