JP2009289778A - Silicon wafer cleaning method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method and a cleaning device that prevent the device from becoming huge excessively even in the case of a silicon wafer having an increased aperture, also reduce the amount of used chemical with respect to the aperture. <P>SOLUTION: In the cleaning method of a silicon wafer, the silicon wafer is floated and moved in a cleaning liquid by a stream of water blown out from a lower portion to an upper oblique portion for cleaning during movement. In the silicon wafer cleaning device, a cleaning tank and a plurality of supply openings provided at the bottom of the cleaning tank for blowing out a stream of water in the direction of travel of the silicon wafer are arranged at least in a row in the travelling direction of the silicon wafer, and the silicon wafer is floated and moved from the inlet side to the outlet side of the silicon wafer for cleaning. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a silicon wafer cleaning method and a cleaning apparatus. The cleaning method and cleaning apparatus of the present invention are particularly suitable for cleaning a silicon wafer substrate having a large diameter exceeding 400 mm in diameter.

  The size of a silicon wafer cut out from a silicon single crystal has become larger in a cycle of about 10 years. In device manufacturers, it is desired to increase device manufacturing efficiency by increasing the size of silicon wafers. Under such circumstances, it is planned to manufacture a silicon wafer of about 450 mm having a diameter of about 1.5 times the current diameter of 300 mm in the near future.

Conventionally used silicon wafer cleaning techniques are a carrier batch cleaning system, a carrierless batch cleaning system, and a rotating single wafer cleaning system (Non-Patent Documents 1 and 2).
"Ultra-precision wafer surface control technology", Science Forum, Inc. (Chapter 9: Cleaning Technology, Published February 28, 2000) "Cleaning technology for the new silicon wafer surface", Realize Science and Technology Center Co., Ltd. (May 28, 2000, Chapter 6: Silicon wafer cleaning technology)

  However, if the conventional batch cleaning method is applied to a silicon wafer with a large diameter as it is, the apparatus becomes enormous and an increase in the amount of chemicals used due to the enlargement of the processing tank is essential, which inevitably causes cost problems. To do. Therefore, there is a need for a cleaning method and apparatus that take into account the excessive enlargement of the apparatus and the reduction in the amount of chemicals used.

  In addition, as the substrate size increases, the dimensions of various processing equipment must be increased, and from the viewpoint of effective use of the clean room, a technology that can simultaneously carry and clean wafers is necessary. Then, the present inventors considered.

  Accordingly, an object of the present invention is to provide a cleaning method and apparatus capable of reducing the amount of chemical solution to be used for the diameter of the apparatus without excessively enlarging the apparatus even for a silicon wafer having a large diameter of about 450 mm. It is to provide.

  In order to solve the above problems and achieve the object of the present invention, the present inventors have studied variously, a water flow is generated obliquely from the lower part of the cleaning tank, the wafer is moved by this water flow, and the wafer is moved during this movement. The present invention has been completed by finding that it is possible to achieve both wafer cleaning and wafer conveyance by cleaning.

  According to a first aspect of the present invention, there is provided a silicon wafer cleaning method, wherein a silicon wafer is floated and moved in a cleaning liquid by a water flow blown obliquely upward from below, and cleaned during the movement.

The second aspect of the present invention has a plurality of blowout ports arranged in at least one row in the movement direction of the silicon wafer, and blows out a water flow in the movement direction of the silicon wafer at the bottom of the washing tank and the washing tank,
A silicon wafer cleaning apparatus for cleaning a silicon wafer while floating and moving from the inlet side to the outlet side of the silicon wafer.

  According to the present invention, since wafer transfer is carried out in a water stream, it becomes possible to carry out wafer cleaning processing simultaneously with the transfer, and therefore there is no need for buffers or stockers for retaining workpieces before and after various processing processes. Cleaning treatment is possible. In addition, it is possible to provide a cleaning method and apparatus that do not require external drive means (rollers, belts, robots, etc.) for wafer transfer during cleaning.

  The silicon wafer cleaning method of the present invention is characterized in that the silicon wafer is floated and moved in the cleaning liquid by a water flow blown obliquely upward from below the silicon wafer, and is cleaned during the movement.

  This silicon wafer cleaning method of the present invention can be implemented, for example, by the following silicon wafer cleaning apparatus of the present invention. The silicon wafer cleaning apparatus of the present invention has a plurality of outlets arranged in at least one line in the moving direction of the silicon wafer, and has a plurality of outlets for blowing a water flow in the moving direction of the silicon wafer at the bottom of the cleaning tank and the cleaning tank. This is an apparatus for cleaning while floatingly moving a silicon wafer from the entrance side to the exit side of the wafer.

  The silicon wafer cleaning apparatus of the present invention will be described with reference to the schematic sectional view of the cleaning apparatus of the present invention shown in FIG.

  The cleaning apparatus 1 has a plurality of outlets 20 for blowing a water flow in the moving direction (in the direction of the arrow) of the silicon wafer SW to the cleaning tank 10 and the bottom 11 of the cleaning tank 10. The cleaning tank 10 is for holding cleaning liquid for cleaning silicon wafers, such as high pure water, ultra high pure water, or a cleaning agent-containing liquid. Examples of the material of the cleaning tank include quartz, Teflon, and Pyrex glass.

  The planar shape of the cleaning tank 10 is a belt shape. The width of the cleaning tank 10 having a strip shape in the plan view is at least larger than the diameter of the silicon wafer to be cleaned, preferably 1.1 of the diameter of the silicon wafer to be cleaned, when sequentially cleaning one silicon wafer to be cleaned. It can be in the range of 2 to 2 times. Further, two silicon wafers to be cleaned can be sequentially cleaned in parallel. In this case, the width of the cleaning tank 10 is, for example, 1.5 to 2.5 times the diameter of the silicon wafer to be cleaned. Can range. When two silicon wafers to be cleaned are cleaned in parallel, the two silicon wafers to be cleaned can be simultaneously loaded into the cleaning tank 10. Alternatively, the two cleaning silicon wafers can be alternately carried into the cleaning tank 10 so that the transport lanes partially overlap each other. In this case, the width of the cleaning tank 10 may be less than twice the diameter of the silicon wafer to be cleaned, for example. Similarly, three or more silicon wafers to be cleaned can be simultaneously loaded into the cleaning tank 10. Or it can also be carried in to the washing tank 10 sequentially so that the conveyance lanes of three silicon wafers to be cleaned may partially overlap.

  A plurality of outlets 20 are continuously provided in the bottom 11 of the cleaning tank 10 in the moving direction of the silicon wafer. The series of blowout ports 20 is provided in one or a plurality of rows, and the intervals between the series of blowout ports 20 may be equal intervals or may be non-equal intervals between some or all of the blowout ports 20. Moreover, when a series of the blowout ports 20 are provided in a plurality of rows, the arrangement and intervals of the blowout ports 20 may be different depending on each row.

  In the method and apparatus of the present invention, the silicon wafer SW is carried into the cleaning tank 10 filled with the cleaning liquid from the inlet side 12 of the cleaning tank 10, and the water flow from the outlet 20 causes the inlet side 12 to the outlet side of the cleaning tank 10. In FIG. 13, the silicon wafer SW is washed while floating. For bringing the silicon wafer SW into the cleaning tank 10, existing means such as a robot arm can be used. In order to perform cleaning while floating the silicon wafer SW, it is appropriate that the water flow from the blow-out port 20 is generated so as to generate a flow from the inlet side 12 toward the outlet side 13. Therefore, as shown in FIG. 2, the blowout port 20 is provided so that the blowout angle θ of the water flow from the blowout port 20 is in the range of 30 to 60 ° with respect to the moving direction of the silicon wafer. In this case, the angle θ is a value as viewed in a vertical section with respect to the moving direction of the silicon wafer.

  However, in the case where a plurality of rows of the blowout ports 20 are provided, the angle and direction can be different from the blowout angle of the water flow from the blowout ports 20 depending on the position of the row of the blowout ports 20 in the cleaning tank 10. . For example, for the air outlet 20 provided in the vicinity of the center of the cleaning tank 10, the water flow outlet angle is parallel to the moving direction of the silicon wafer when the cleaning tank 10 is viewed in plan and the vertical cross section is viewed. The angle is within the range of 30 to 60 °, but a relatively small angle can impart a large amount of driving force.

  On the other hand, for the air outlets 20 provided near both sides of the cleaning tank 10, the water flow outlet angle may be parallel to the moving direction of the silicon wafer when viewed in plan, but in the central direction, for example, 1 to 20 It is possible to tilt the water flow so that the silicon wafer SW does not easily come into contact with the inner wall of the cleaning tank 10. In this case, the angle when viewed in the vertical section can be within the range of 30 to 60 °.

  The diameter and shape of the blowout port 20 are not particularly limited, but are appropriately determined in consideration that the movement and floating of the silicon wafer SW in the cleaning tank 10 can be maintained in a good state. For the series of outlets 20, the outlets 20 having the same diameter and shape can be provided, but the outlets 20 having different diameters and shapes can be provided depending on positions. Furthermore, the diameter and the shape of the mouth of the outlet 20 also affect the flow velocity of the water stream to be blown out. The flow rate of the water flow to be blown out is appropriately determined in consideration of the fact that the movement and floating of the silicon wafer SW in the cleaning tank 10 can be maintained in a good state, and is, for example, in the range of 0.1 to 10 L / min. Can do. Accordingly, the diameter and shape of the outlet 20 are appropriately set so as to obtain the flow velocity of the water stream to be blown out.

  The water flow from the outlet 20 can be generated by circulating the cleaning liquid in the cleaning tank 10. For example, the cleaning liquid is circulated by providing a cleaning liquid discharge port 14 in the vicinity of the outlet side 13 of the cleaning tank 10, pressurizing the discharged cleaning liquid with a pump P provided outside the cleaning tank 10, and supplying it to the outlet 20. This can be done. At this time, the cleaning liquid discharged from the discharge port 14 can be circulated as it is or after purification. In addition, a part of the circulating cleaning liquid can be discharged out of the system, and a fresh cleaning liquid can be replenished to supplement it.

  FIG. 1 shows two cleaning tanks. A plurality of cleaning tanks can be sequentially provided to continuously clean the silicon wafer SW. The silicon wafer SW can be carried into the cleaning tank 10 by using existing means such as a robot arm as described above. The silicon wafer SW can be unloaded from the cleaning tank 10 by, for example, unloading means provided on the outlet side 13 in the cleaning tank 10. Although two cleaning tanks are shown in FIG. 1, three or more cleaning tanks may be provided in succession and cleaned sequentially with different cleaning liquids.

  The silicon wafer SW to be cleaned may be made of a semiconductor other than a silicon wafer, and the size can be applied to a wafer of any diameter such as φ200 mm, φ300 mm, and φ450 mm. However, the method and apparatus of the present invention is particularly suitable for cleaning large silicon wafers having a diameter in the range of 400 to 500 mm.

  Hereinafter, the present invention will be described based on examples.

  Using a silicon wafer cleaning apparatus in which a plurality of oblique jet nozzles are provided in parallel at the lower part of the cleaning tank shown in FIG. 1, a φ450 mm silicon wafer placed on the water stream formed by spraying a positively pressurized water stream with a pump or the like Washed while transporting.

  The size of the cleaning tank is 500 mm wide × 2000 mm long × 30 mm deep.

The number, angle, and area of the jet nozzles provided in the cleaning tank are as follows.
Circular outlets with a diameter of 1 cm were arranged in the lower part of the tank at an ejection angle [θ] of 45 °.
The arrangement pitch was 5 cm in the XY direction.
From the same outlet, liquid injection was performed using means such as a pump so that a liquid flow was formed at a flow rate of 1 L / min.

  Useful in the field of silicon wafer production.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional explanatory view of a silicon wafer cleaning apparatus of the present invention. The expanded schematic sectional explanatory drawing of the blower outlet vicinity of the silicon wafer cleaning apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Washing tank 11 Bottom part 12 Inlet side 13 Outlet side 14 Outlet 20 Outlet

Claims (7)

A silicon wafer cleaning method, wherein a silicon wafer is floated and moved in a cleaning solution by a water flow blown obliquely upward from below, and is cleaned during the movement. The method according to claim 1, wherein a water flow blowing angle is in a range of 30 to 60 ° with respect to a moving direction. The method according to claim 1, wherein the water stream is generated by circulating the cleaning liquid. The method according to any one of claims 1 to 3, wherein a flow rate of the water stream to be blown is in a range of 0.1 to 10 L / min. The method according to claim 1, wherein the diameter of the silicon wafer is in the range of 400 to 650 mm. A plurality of outlets that blow out a water stream in the moving direction of the silicon wafer at the bottom of the cleaning tank and the cleaning tank, and arranged in at least one row in the moving direction of the silicon wafer,
A silicon wafer cleaning apparatus for cleaning a silicon wafer while floating and moving from the inlet side to the outlet side of the silicon wafer. The cleaning apparatus according to claim 6, wherein a blowing angle of the water flow at the blowing port is in a range of 30 to 60 ° with respect to a moving direction of the silicon wafer.