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
  • H01L21/04—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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B37/00—Lapping machines or devices; Accessories
  • B24B37/34—Accessories
  • B24B37/345—Feeding, loading or unloading work specially adapted to lapping
• • 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
  • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
  • H01L21/67005—Apparatus not specifically provided for elsewhere
  • H01L21/67011—Apparatus for manufacture or treatment
  • H01L21/67017—Apparatus for fluid treatment
  • H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
  • H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing

Definitions

• the present invention relates to a method for storing a carrier used in polishing a silicon wafer. In some polishing processes, both surfaces of the wafer are polished simultaneously.
• Carriers have hitherto been stored in a dry condition, for example, as shown in Fig. 3, where carriers 3 are placed horizontally on a plurality of carrier setters 2 disposed on rollers 4 in a carrier repository 1. It has been found that because of such dry storage, scratches continue to occur at unacceptable levels. Further, the number of scratches on a silicon wafer increases with the number of times a carrier is used in the polishing process.
• the present invention aims to provide a method for storing a wafer polishing carrier, which carrier is stored in a manner that will reduce scratches on a silicon wafer which scratches are created during polishing the silicon wafer particularly when polished on both of its surfaces simultaneously.
• the present invention provides for a method of polishing a silicon wafer that results in fewer scratches on the wafer; the provision of such a method of using a wafer carrier that can be utilized with current polishing equipment without significant modification; the provision of such a method that is economical to use; and the provision of such a method that can be used in wafer polishing processes that polish both sides of a wafer simultaneously.
• the present invention provides a method for storing a carrier used in polishing a silicon wafer.
• the method includes storing the carrier completely immersed in a liquid containing deionized water prior to use with a wafer in a wafer polishing step.
• Fig. 1 is a schematic explanatory view showing an embodiment of a method for storing a carrier of the present invention.
• Fig. 2 is a schematic explanatory view showing another embodiment of a method for storing a carrier of the present invention.
• Fig. 3 is a schematic explanatory view showing an embodiment of a conventional method for storing a carrier.
• Fig. 4 is a graph showing a correlation between number of polishing and rate of occurrence of scratches.
• the present invention provides a method for storing a carrier that is used during the silicon wafer polishing step of the polishing process.
• the wafers are preferably simultaneously polished on both surfaces.
• the method includes storing the carrier completely immersed in a storage liquid such deionized water or a liquid mixture including deionized water prior to use in the polishing step.
• the storage liquid be at a temperature in the range of about 20°C through about 80°C during storage of the carriers. It is also preferred that the storage liquid be subjected to filter-circulation cleaning during carrier storage, however, it is envisioned that the storage liquid may be filtered at other times in addition to or instead of during carrier storage .
• a further method for storing a carrier for simultaneously polishing both surfaces of silicon wafer characterized in that the carrier is stored completely immersed in storage liquid including a mixture of liquids and also one or more liquids containing dissolved solids.
• the major component of the storage liquid is deionized water. It is preferable that the following components be added to the deionized water to obtain the liquid mixture and added in the indicated amounts by weight of deionized water: surface active agent (0.1 - 5% by weight); aqueous ammonia and hydrogen peroxide; and surface active agent (0.1 - 5% by weight + aqueous ammonia and hydrogen peroxide) .
• the surface active agent may be a soluble solid.
• the storage liquid has pH preferably of 7 - 12. Further, the storage liquid is preferably subjected to filter-circulation cleaning.
• a carrier and a brush for cleaning abrasive polishing pads are stored under the condition that a carrier and a brush are completely immersed in the storage liquid.
• a carrier is stored completely immersed in storage liquid. Therefore, the carrier can be stored and removed from storage in a clean condition since the carrier can be isolated from contaminants.
• the carrier can be easily washed of contaminants since contaminants are preferably not allowed to dry on the carrier and do not adhere as readily to the carrier even if the carrier is initially contaminated. Thus, the contaminants available to cause scratches during polishing are reduced as is the number of scratches .
• the method of the present invention can be applied not only to the aforementioned carrier for polishing, but also to a brush used to clean an abrasive polishing pad.
• Deionized water used in the present invention is preferably super deionized water refined by the use of an electric recuperation type ion-exchanger in which an ion- exchange resin and an ion- -exchange film are used in combination or refined with a reverse permeation apparatus.
• the liquid mixture of the present invention is preferably prepared by adding a surface active agent in an amount of about 0.1 - 5% by weight (absent any water) of deionized water in the resulting mixture.
• a volume ratio of aqueous ammonia : aqueous hydrogen peroxide : deionized water is controlled within the approximate range of from 1:1:10 to 1:1:200.
• a surface active agent usable in the present invention is selected from cationic surface-active agents, anionic surface- active agents, nonionic surface-active agents and amphoteric surface-active agents. Nonionic surface-active agents and amphoteric surface-active agents are preferable for removing contaminants .
• a vessel 13 for storing a carrier is filled with storage liquid which is preferably first filter- cleaned.
• a part of the aforementioned deionized water or liquid mixture (storage liquid) is introduced to a filter 10 from a water-suction port 11 arranged at the bottom of the vessel 13 by the use of a circulation pump 9, filter-cleaned by the filter 10, and continuously supplied to the vessel 13 through a water-supply port 12 arranged in the upper portion of the vessel 13.
• the filter 10 it is preferable to use a filter of 0.05 - l.O ⁇ m filtration.
• a carrier should be placed in the vessel before drying after use to help in particle removal from the carrier. Because the particles are not dry, they do not readily adhere to the carrier and even if particles adhere to the carrier, the carrier can be easily washed away prior to use or reuse of the carrier. It is preferable that a carrier is taken out of and placed in the vessel for storing a carrier by the use of, for example, an arm 5 shown in Fig. 1.
• the arm 5 includes a plurality of grooves 6 each for holding a carrier 3 , a stopper 7 fixing the arm 5 during a time when the arm 5 is positioned for removing or introducing a carrier, and a supporting portion 8 capable of supporting the arm 5 at predetermined portions of the vessel 13 in such a manner that the arm 5 (or the supporting portion 8) can slide up and down.
• the carrier 3 may be introduced into the vessel for storing the carrier immersed in the storage liquid.
• a carrier 3 may be suspended from a rack-shaped repository shelf 14.
• the shelf is suspended in the vessel 13 as with a wire 16 which is also connected to a winch means 18 and operable to move the shelf up and down to predetermined positions within the vessel 13 as shown in Fig. 2.
• the wire 16 be made of a material having low dusting characteristics.
• nylon or the like can be suitably used as the material.
• an open top of the vessel 13 be normally sealed during carrier storage to prevent particles in the ambient atmosphere from being introduced into the vessel 13. It is also preferred the vessel 13 be disposed in a clean air environment such as in a clean room.
• the present invention is described in more detail on the basis of Examples. However, the present invention is by no means limited to these Examples.
• the rate of occurrence of scratches (count/si) per a silicon wafer was obtained by subjecting silicon wafers to eye-observation in a darkroom by the use of collimate light having a luminous intensity of 10 5 lux and determining observable scratches as scratches caused by contaminants.
• a carrier 3 was stored, by use of the vessel 13 shown in Fig. 1 in such a manner that it was completely immersed in deionized water having a temperature of 40°C while circulating deionized water cleaned by the filter 10 (1.0 filtration filter) .
• a carrier 3 was stored, by the use of the vessel 13 shown in Fig. 1 in such a manner that it was completely immersed in a liquid mixture having a temperature of 40°C and pH of about 10 while circulating a filter-cleaned mixed liquid by a filter 10 (1.0 ⁇ m filtration filter).
• the liquid mixture was prepared by adding 0.5 wt% of L-64 (produced by BASF) as a surface active agent, 0.5 wt% of 30% aqueous ammonia, and 0.5 wt% of 30% aqueous hydrogen peroxide (based on total weight of deionized water in the resulting mixture) to deionized water.
• a carrier 3 was stored in a dry condition by the use of a container 1 for storing a carrier shown in Fig. 3.
• a silicon wafer was subjected to polishing (normal manner) several times on both surfaces simultaneously by the use of the carrier.
• FIG. 4 A correlation between number of polishing steps on the wafer and rate of occurrence of scratches is shown in Fig. 4. As Fig. 4 shows, the rate of occurrence of scratches on a silicon wafer was reduced in Examples 1 and 2 in comparison with Comparative Example.
• Example 2 a rate of occurrence of scratches on a silicon wafer was reduced the most by adding a surface active agent, aqueous ammonia and aqueous hydrogen peroxide to deionized water in comparison with the case where only deionized water was used.
• a carrier can be stored in a clean condition, and scratches on a silicon wafer which are sustained during polishing of the silicon wafer on both surfaces simultaneously can be reached.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Mechanical Engineering (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
• Prevention Of Fouling (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

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• 1998
  • 1998-12-24 JP JP36687398A patent/JP2000190208A/ja not_active Withdrawn
• 1999
  • 1999-12-08 EP EP99964166A patent/EP1142003A1/de not_active Withdrawn
  • 1999-12-08 WO PCT/US1999/029078 patent/WO2000039841A1/en not_active Application Discontinuation
  • 1999-12-08 CN CN99814852A patent/CN1331838A/zh active Pending
  • 1999-12-08 KR KR1020017005828A patent/KR20010080964A/ko not_active Application Discontinuation
  • 1999-12-23 MY MYPI99005694A patent/MY130885A/en unknown
  • 1999-12-24 TW TW088122945A patent/TW439137B/zh active

Non-Patent Citations (1)

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