JP2010034441A - Cleaning method for wafer, and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently shorten a cleaning time for a wafer by cleaning the wafer without fixing it and thus omitting an operation for re-gripping the wafer. <P>SOLUTION: The cleaning method for the wafer includes jetting pure water over the entire surface of a disk-like base 12, having an external diameter smaller than the diameter of the wafer 11 and installed in a horizontal direction, to uniform height from the base 12; floating the disk-like wafer, placed concentrically with the base, over the base with the jetted pure water; and cleaning the lower surface of the wafer with the pure water jetted from the base. A cleaning device 10 includes the disk-like base 12 which has the external diameter smaller than the diameter of the wafer, has a plurality of equal-diameter jet holes 13a formed over the entire surface, and also has a hollow portion 12a communicating with the jet holes, formed in the base, and is installed in the horizontal direction, and a pure water supply means 21 of jetting the pure water from the plurality of jet holes through the hollow portion to the uniform height over the entire surface of the base. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a single wafer cleaning method and apparatus for cleaning a disk-shaped semiconductor wafer one by one.

  Advances in the technology of semiconductor integrated circuits (LSIs) that play a central role in the development of electronic and communication devices in recent years have greatly contributed. In general, in the manufacture of a semiconductor device such as an LSI, a semiconductor wafer formed by polishing, chamfering or the like on a wafer obtained by slicing a silicon single crystal pulled by the CZ method is used. In such a device manufacturing process using a semiconductor wafer or a processing process of the semiconductor wafer itself, for example, heat treatment may be performed for the purpose of controlling the concentration distribution of precipitates contained in the wafer. After the application, the surface is washed with pure water.

Conventional wafer cleaning is known as a single wafer type that cleans the wafers one by one. As the single wafer cleaning device, a plate of aluminum or stainless steel coated or covered with a corrosion-resistant resin, There is known one provided with a wafer support provided at a distance in parallel to the upper surface of the plate (see, for example, Patent Document 1). The wafer support is configured to hold the wafer to be cleaned horizontally about 3 mm above the surface of the plate. Specifically, the wafer support has a plurality of clamps for holding the wafer, holds the periphery of the wafer by the plurality of clamps, and fixes the wafer horizontally above the plate. The wafer support is configured so that the wafer can be rotated or spun horizontally around the central axis at a speed of 0 to 6000 rpm. In this cleaning apparatus, pure water is supplied between the plate and the wafer, the gap between the wafer and the plate is filled, and the back surface of the wafer can be cleaned with the pure water.
JP-T-2004-519088 (Specifications [0023] to [0025], FIG. 6a)

However, in the conventional cleaning apparatus, since the wafer to be cleaned is fixed horizontally by a plurality of clamps provided on the wafer support, there is a problem that the periphery of the wafer held by the clamp cannot be sufficiently cleaned. To solve this problem, the position of the clamp that holds the wafer is changed during cleaning, but the work to re-hold the wafer occurs and the cleaning time of the wafer cannot be shortened sufficiently. There was also a point.
An object of the present invention is to provide a wafer cleaning method and apparatus capable of sufficiently shortening the wafer cleaning time by cleaning the wafer without fixing and omitting the operation of re-gripping the wafer.

According to the first aspect of the present invention, pure water is ejected from a horizontally installed disk-shaped base having an outer diameter smaller than the wafer diameter over the entire surface of the base to a uniform height. The wafer cleaning method is characterized in that a disk-shaped wafer placed concentrically with the substrate is floated horizontally and the lower surface of the wafer is cleaned with pure water ejected from a base.
The invention according to claim 2 is the invention according to claim 1, wherein pure water is supplied to the upper surface of the wafer by one or more cleaning nozzles from above the wafer that floats from the base when cleaning the lower surface of the wafer. This is a cleaning method for cleaning the upper surface.
The invention according to claim 3 is the invention according to claim 1 or 2, wherein the wafer floating from the base is horizontally rotated in the circumferential direction by supplying water from the cleaning nozzle and jetting pure water from the base. It is a cleaning method.

The invention according to claim 4 is a horizontally installed disk in which a plurality of ejection holes having the same diameter are formed on the entire surface, and a hollow portion communicating with the ejection holes is formed inside the base. And a pure water supply means for ejecting pure water from a plurality of ejection holes to a uniform height over the entire surface of the base through the hollow portion, and placed concentrically with the base above the base by the ejected pure water A wafer cleaning apparatus, wherein a disk-shaped wafer is floated horizontally, and the lower surface of the wafer is cleaned with pure water ejected from a base.
The invention according to claim 5 is the invention according to claim 4, further comprising one or more downwardly directed cleaning nozzles above the base, and the cleaning nozzle from above the wafer that floats from the base when cleaning the lower surface of the wafer. The cleaning apparatus supplies pure water to the upper surface of the wafer to clean the upper surface of the wafer.

The invention according to claim 6 is the invention according to claim 4 or 5, wherein a part of the plurality of ejection holes is provided inclined at 15 to 60 degrees with respect to the vertical direction, and pure water from the ejection holes is provided. The cleaning apparatus is configured to horizontally rotate a wafer floating from a base by jetting in the circumferential direction.
The invention according to a seventh aspect is the invention according to any one of the fourth to sixth aspects, wherein a plurality of guides higher than the position of the floating wafer are erected on the outer periphery of the base, and the floating wafer is located above the base. It is the washing | cleaning apparatus comprised so that it might separate from.

  In the wafer cleaning method and apparatus of the present invention, pure water is ejected from a horizontally installed disk-shaped base having an outer diameter smaller than the wafer diameter over the entire base surface to a uniform height. A disk-shaped wafer placed concentrically with the base above the base is floated horizontally, and the lower surface of the wafer is cleaned with pure water ejected from the base, so that a plurality of wafers to be cleaned are provided on a conventional wafer support. Do not fix it horizontally with a clamp. For this reason, it is possible to prevent a situation in which the portion gripped by the clamp cannot be cleaned, and it is not necessary to change the position of the clamp that grips the wafer during cleaning. For this reason, it is possible to omit the operation of re-gripping the wafer and sufficiently shorten the wafer cleaning time.

Next, the best mode for carrying out the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, the wafer cleaning apparatus 10 includes a base 12 on which a disk-shaped wafer 11 (FIG. 1) that is installed horizontally and is a cleaning target is placed. The base 12 in this embodiment has a hat-like upper plate 13 made of a fluororesin and a flat plate-like lower plate 14 made of a vinyl chloride resin. As shown in FIG. 1, a plurality of female screws 13b are formed in the circumferential direction on the flange 13a around the hat-shaped upper plate 13, and the lower plate 14 that opposes the female screws 13b has a countersink from the lower side. A counterbore 14a is formed. Then, as shown in the enlarged view of FIG. 1, a countersunk screw 16 is inserted into the countersink hole 14a from below and screwed into a female screw 13b formed on the flange 13a of the upper plate 13 to thereby lower the lower plate. 14 is attached to the upper plate 13, and a hollow portion 12 a is formed inside the base 12 composed of the upper plate 13 and the lower plate 14.

  As shown in FIGS. 1 to 3, the top surface 13 c of the upper plate 13 is formed flat, and its outer diameter d is 1.5 to 5% smaller than the outer diameter D of the wafer 11 to be cleaned. . A plurality of ejection holes 13d having the same diameter communicating with the hollow portion 12a inside the base 12 are formed on the entire top surface 13c. In FIG. 2, the outer diameter D of the wafer 11 to be cleaned is 30 cm, and the outer diameter d of the top surface 13c of the base 12 is 290 cm. The ejection holes 13d have a diameter of 1 mm and are formed on the entire top surface 13c at a pitch of 15 mm.

  As shown in FIG. 1, the cleaning device 10 for the wafer 11 ejects pure water from the plurality of ejection holes 13 d through the hollow portion 12 a in the base 12 to a uniform height over the entire top surface 13 c of the base 12. A pure water supply means 21 is provided. In this example, the height from the top surface 13c from which pure water is ejected is about 3 mm. The pure water supply means 21 includes a pure water tank (not shown), a connecting pipe 22 that connects the tank and the base 12, a valve 23 that is provided between the connecting pipe 22 and opens and closes the connecting pipe 22, and is not shown. And a supply pump. A female screw hole 14b communicating with the hollow portion 12a is formed at the center of the lower plate 14 of the base 12, and one end of the connecting pipe 22 is connected to the female screw hole 14b. The other end of the connecting pipe 22 is connected to a pure water tank (not shown). Connected. A supply pump (not shown) is configured to be able to supply pure water stored in a pure water tank to the hollow portion 12a of the base 12 through the connecting pipe 22, and the valve 23 is supplied to the base 12 by opening and closing the connecting pipe 22. It is configured to adjust the amount of pure water.

  In the cleaning device 10, the pure water supplied to the hollow portion 12a of the base 12 via the connecting pipe 22 is ejected from the plurality of ejection holes 13d to the top surface 13c via the hollow portion 12a. The pure water is configured so as to horizontally float a disk-shaped wafer 11 placed concentrically with the base 12 above the base 12. On the other hand, some of the plurality of ejection holes 13d are provided with an inclination of 15 to 60 degrees with respect to the vertical direction. In this embodiment, 10% of the plurality of ejection holes 13d are provided inclined in the circumferential direction, and the wafer 11 that floats from the base 12 by the ejection of pure water from the ejection holes 13d is horizontally rotated in the circumferential direction. Configured to let The wafer 11 that floats from the base 12 and rotates horizontally in the circumferential direction is configured such that the lower surface of the wafer 11 is cleaned by pure water ejected from the base 12.

  A plurality of female screw holes 13e are formed on the flange 13a of the upper plate 13 of the base 12 on a circumference larger than that of the wafer 11, and a plurality of guides 24 higher than the position of the floating wafer 11 are provided in the female screw holes 13e. Screwed together. Therefore, the guide 24 is erected on the outer periphery of the base 12 and is configured to prevent the floating wafer 11 from being detached from above the base 12. One or two or more cleaning nozzles 26 are provided above the base 12. The cleaning nozzle 26 is configured to supply pure water to the upper surface of the wafer 11 from above the wafer 11 that floats from the base 12 when the lower surface of the wafer 11 is cleaned to clean the upper surface of the wafer 11.

Next, the wafer cleaning method of the present invention using such an apparatus will be described.
First, pure water is ejected from a horizontally installed disk-shaped base 12 having an outer diameter d smaller than the outer diameter D of the wafer 11 over the entire surface of the base 12 to a uniform height. The pure water is ejected by driving a supply pump (not shown) to supply pure water stored in a pure water tank to the base 12 via the connecting pipe 22 and opening and closing the connecting pipe 22 by the valve 23 to the base 12. This is done by adjusting the amount of pure water supplied. Then, the wafer 11 is placed on the ejected pure water, and the disc-shaped wafer 11 placed concentrically with the base 12 above the base 12 is floated horizontally by the ejected pure water. Then, the lower surface of the wafer 11 that is levitated by pure water ejected from the base 12 can be washed with the pure water.

  Here, the wafer 11 is concentric with the base 12 because the outer diameter d of the top surface 13c of the base 12 is smaller than the outer diameter D of the wafer 11, and is an enlarged view of FIG. As shown in FIG. 2, the jetted pure water reaches the outer periphery of the wafer 11 as indicated by an arrow W on the lower surface of the wafer 11 and then descends from the periphery of the top surface 13c of the base 12 by its own weight. When the outer diameter d of the top surface 13c of the base 12 is smaller than the outer diameter D of the wafer 11, when pure water on the outer periphery of the wafer 11 descends from the periphery of the top surface 13c of the base 12, the surface tension of pure water The pure water pulls the periphery of the wafer 11 toward the periphery of the top surface 13 c of the base 12, whereby the wafer 11 is always pulled to the center of the base 12 and the wafer 11 is concentric with the base 12.

  Therefore, in the cleaning method of the present invention, the wafer 11 to be cleaned is not fixed horizontally by a plurality of clamps provided on a conventional wafer support. For this reason, it is possible to prevent a situation in which a portion held by the clamp cannot be cleaned, and it is not necessary to change the position of the clamp that holds the wafer 11 during the cleaning. That is, in the cleaning method of the present invention, since the wafer 11 is cleaned without being fixed, the operation of re-gripping the wafer 11 can be omitted and the cleaning time of the wafer 11 can be sufficiently shortened.

  Further, in this embodiment, since the cleaning nozzle 26 is provided, pure water is supplied to the upper surface of the wafer 11 by one or more cleaning nozzles 26 from above the wafer 11 that floats from the base 12 when the lower surface of the wafer 11 is cleaned. By doing so, the upper surface of the wafer 11 can be cleaned. And since the wafer 11 which floats from the base 12 is horizontally rotated in the circumferential direction by the supply of water from the cleaning nozzle 26 and the ejection of pure water from the base 12, it is possible to avoid occurrence of unevenness in the cleaning. it can.

It is a section lineblock diagram of a cleaning device of an embodiment of the present invention. It is a top view of the apparatus. It is a perspective view of the device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cleaning apparatus 11 Wafer 12 Base 12a Hollow part 13d Ejection hole 21 Pure water supply means 24 Guide 26 Cleaning nozzle

Claims (7)

  Pure water is ejected from a horizontally installed disc-shaped base having an outer diameter smaller than the wafer diameter over the entire surface of the base to a uniform height, and is placed concentrically with the base above the base by the ejected pure water. A wafer cleaning method, wherein a disk-shaped wafer is floated horizontally, and the lower surface of the wafer is cleaned with pure water ejected from the base.   The cleaning method according to claim 1, wherein pure water is supplied to the upper surface of the wafer by one or more cleaning nozzles from above the wafer that floats from the base when the lower surface of the wafer is cleaned.   The cleaning method according to claim 1 or 2, wherein the wafer floating from the base is horizontally rotated in the circumferential direction by supplying water from the cleaning nozzle and ejecting pure water from the base. A horizontally installed disk-shaped base having an outer diameter smaller than the wafer diameter, a plurality of ejection holes having the same diameter formed on the entire surface, and a hollow portion communicating with the ejection holes formed inside the base,
Comprising pure water supply means for jetting pure water from the plurality of jet holes through the hollow portion to a uniform height over the entire surface of the base;
A disk-shaped wafer placed concentrically with the base above the base by the ejected pure water is floated horizontally, and the lower surface of the wafer is washed with pure water ejected from the base. Cleaning device.   One or more downward cleaning nozzles are further provided above the base, and pure water is supplied to the upper surface of the wafer by the cleaning nozzle from above the wafer that floats from the base when the lower surface of the wafer is cleaned. The cleaning apparatus according to claim 4 for cleaning.   A part of the plurality of ejection holes is provided with an inclination of 15 to 60 degrees with respect to the vertical direction, and the wafer floating from the base by the ejection of pure water from the ejection holes is horizontally rotated in the circumferential direction thereof. The cleaning apparatus according to claim 4 or 5, wherein the cleaning apparatus is configured.   The plurality of guides higher than the position of the floating wafer are erected on the outer peripheral portion of the base, and are configured to prevent the floating wafer from being detached from above the base. The cleaning device described.

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