JPS6221237A - Table for wafer positioning - Google Patents

Abstract

PURPOSE:To simplify the constitution of a table for wafer positioning by a method wherein, when a semiconductor wafer is positioned on the table, gas jet nozzles located inside the peripheral edge of the wafer are provided on the surface of the table whereon the wafer is placed, at equal intervals and the wafer is levitated by the jet gas flows and is positioned on the table. CONSTITUTION:A table 10 for transferring a semiconductor wafer 2 is formed in a box type, the interior thereof is used as a gas chamber 13, the sidewall on one side of the table 10 is provided with a connection opening 14 for gas inflow, and moreover, plural gas jet nozzles 15 located on the side inner slightly than the peripheral edge of the wafer 2 placed on the flat surface 11 of the top surface of the table 10, are provided on the flat surface 11 at equal intervals. The wafer 2 is levitated by gas flows 15 to jet from the jet nozzles 15 in such a way to the prescribed height within an outer peripheral edge flange 12 surrounding the wafer 2, and the wafer 2 is positioned by the gas flows 15a. Here it does not matter whether the jet nozzles 15 are provided in two rows or shaped in a cacoon-form. According to such a way, the wafer 2 can be kept in a clean state, and a linkage mechanism, which is normally used, and so forth become unnecessary.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a positioning table for aligning the center of a wafer. It is suitable for use as an intermediate table or the like installed for matching purposes.

(Prior Art) Conventionally, when a wafer is removed from a cassette and transferred to a holder of a process machine via an arm equipped with a vacuum suction cup, the holder is An intermediate table is provided in front, and the center of the wafer is previously aligned on the intermediate table.

FIG. 4A is a plan view of a main part of a conventional wafer positioning device installed on the intermediate table and used for centering the wafer, FIG. 4B is a sectional view taken along the line VI-IV in FIG. 4A, and FIG. 4C is a sectional view showing a positioned state. In the figure, reference numerals 1 and 1 denote two annular pawls that support the periphery of the lower surface of the wafer 2 over an angle of 120 degrees each. The wafer 2 has a horizontal part 1a that supports the peripheral part of the lower surface of the wafer 2, and a collar 1b that is formed on the outside of the horizontal part 1a and rises upward to regulate the position of the circumferential surface of the wafer 2. '1
c is formed. And these two claws 1. I#
'i, It is supported on the intermediate table via a link mechanism (not shown) so that it can be expanded and narrowed symmetrically in the left-right direction as shown in FIG. 4B.

As described above, the link mechanism moves the wafer 2 away from the suction cup from directly above both pawls 1, 1 (Figure 4B shows the position of the pawls at this time), which are installed at predetermined positions on the intermediate table. Then, place the wafer 2 between the claws 1 and 10 in the open position. Next, when both the claws 1, 1 are closed from the left and right sides, the center of the wafer is positioned on the inner slope 1cK of the periphery of the wafer 2.

(Problems to be Solved by the Invention) In the conventional wafer positioning device described above, the claw l
The peripheral portion of the lower surface of the wafer 2 is brought into direct contact with the horizontal portion Ia of the wafer 2 . However, since a resist m is normally formed on the lower surface of the wafer 2, there is a risk that the resist m at the abutting portion may rub against the horizontal portion 1a and be scratched, or the resist film may peel off. There were problems such as this becoming a source of dust.

The technical problem of the present invention is to solve the above-mentioned problems of the prior art and to position the wafer without bringing the lower surface of the wafer into direct contact with the support table.

(No means for solving the problems) In order to solve the problems and technical problems of the prior art described above, the present invention provides the following methods: It is characterized by a plurality of gas ejection holes arranged on the circumference near the outer periphery of the wafer. The above-mentioned gas ejection hole can be formed in various shapes such as a circular opening or a cocoon-shaped opening. The wafer transferred above is lifted up and floated on the flat surface by gas ejected from a plurality of gas ejection holes arranged circumferentially near the outer periphery of the wafer, and The horizontal position is regulated by a gas flow flowing along the wafer in a direction perpendicular to the wafer surface.

Therefore, the wafer is positioned at a predetermined position on the table by the gas ejected from the plurality of gas ejection holes drilled at predetermined positions.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1A is a plan view of a wafer positioning table showing a first embodiment of the present invention, FIG. 1B is a cross-sectional view taken along line II in FIG. 1A, and FIG. 1C is a cross-sectional view showing an operating state. The cheagle 10 has a circular flat surface 11 with a diameter larger than the wafer outer diameter, and the shoulder edge of the flat surface 11 has a floating height fft of the wafer.
K is integrally formed with boxwood edges 12 having approximately the same height. Further, a gas chamber 13 is provided below, and the gas chamber 13 is communicated with an external compression source via a connection port 14 . As shown in FIG. 1C, on the flat surface 11, a plurality of gas jets are provided around the entire circumference near the outer circumferential surface of the wafer 2, that is, at a position where the outer circumferential surface of the wafer passes approximately through the center of the hole. Holes 15 are bored at approximately equal intervals.

With the above structure, the wafer 2 transferred to the flat surface 11 of the table 10 is discontinuously disposed along the outer circumferential surface of the wafer, which is formed by the jetted gas flow 15a blown out from the gas jetting hole 15. The horizontal position of the gas is regulated by the gas film, and positioning is performed at a position floating above the flat surface 11. Since the flow 151 is prevented from spreading outward, the horizontal position of the wafer 2 is effectively restricted.

In addition, the position, size, shape of the gas ejection hole, the flow rate of the gas ejected from the hole, the distance from the brim and the height of the brim, etc. should be determined so that turbulence such as vortices does not occur in the curved part of the sea urchin. % is selected to have an appropriate size so that it occupies a stable center position in the floating state.

2A to 2C are similar drawings to FIGS. 18 to 1C showing a second embodiment of the present invention, and in this embodiment, a gas ejection hole 25a formed in a flat surface 21 is shown. and 25b are shifted from each other on concentric circles, and 2
The inner gas ejection holes 25a are drilled across the rows, and the inner gas ejection holes 25a are
The gas ejection holes 25b on the outer side of the wafer 2 are formed near the outer peripheral surface of the wafer 2 in the same manner as the ejection holes 15 of the embodiment. There is no difference in terms of points.

According to this embodiment, as shown in FIG. 2C, the flat surface 2
The Ueno 12 on top of 1 is lifted and floated by the gas ejected from the inner gas ejection hole 25a, and its horizontal position is changed by the ejected gas flow from both the inner gas ejection hole 25a and the outer gas ejection hole 25b. Regulated. In this case, a raised portion 2'2a protruding inward on the inner surface of the collar 22
By providing this, it becomes possible to more actively regulate the horizontal position by imparting a bias toward the outer circumferential surface of the wafer 2 to the gas flow from the outer gas ejection holes 2sb.

In the case of this embodiment as well, the position, size, relationship with the collar, etc. of each hole are determined so that no disturbances such as vortices occur on the outer peripheral surface of the wafer and the wafer occupies a stable center position in a floating state. .

Figures 3 to 3C are similar to Figures 1 to 1C showing a third embodiment of the present invention; This embodiment differs from the first embodiment in that the hole 35 is formed in a cocoon shape.
There is no difference in other respects.

According to this embodiment, as shown in FIG. 3C, the flat surface 3
The wafer 2 on the wafer 1 is lifted and floated by the air ejected from the cocoon-shaped air ejection hole 35, and at the same time, the horizontal position is regulated, which is essentially the same as in the first embodiment. In this embodiment, as described above, the gas ejection holes are formed in a cocoon-like shape with a series of circular openings, so that the floating action of the wafer 1 is promoted and the gas flow flowing around the circumferential surface of the wafer is Since a substantially continuous cylindrical film is formed, the action of regulating the horizontal position of the wafer is also facilitated. However, the consumption of compressed gas increases.

In each of the above-mentioned embodiments, a structure is described in which a raised brim is provided on the outer peripheral edge of the flat surface of the table, but the brim may not be provided. In this case, the gas flow blown out from the gas outlet tends to diffuse outward, but this can be avoided by taking measures such as restricting the blown gas flow and increasing the flow velocity.
It is possible to counteract the above trends.

In addition, although we have explained two types of gas ejection holes, circular and cocoon-shaped, the shape is of course not limited to this, and the compressed gas flow used is usually clean air. However, it is also possible to use other gases as appropriate.

(Effects of the Invention) As explained above, according to the present invention, the following effects are achieved.

(1) By providing a plurality of gas ejection holes on the circumference near the outer periphery of the wafer, the wafer can be floated on the positioning table by gas iK and held at a predetermined position 111. Therefore, there is no risk of scratching the resist film on the bottom surface of the wafer.

(10) Since the wafer can be positioned by the gas flow ejected from the compressed gas, there is no need for a link mechanism or the like used in the conventional apparatus, and the structure is simple and costs can be reduced.

011 If the gas is constantly ejected, no dust will get on the table, so the wafer can be kept in a clean state.

[Brief explanation of the drawing]

Fig. 1A is a plan view showing the first embodiment of the present invention, Fig. 1B is a sectional view taken along the line I-I in Fig. 1A, Fig. 6C is a sectional view showing the operating state, and Figs. 2 to 2C. 3A to 3C are similar drawings to FIGS. 1A to 1C showing the second and third embodiments of the present invention, and FIGS. 4A to 40 are plan views of main parts of the conventional device and differences. FIG. 2---Wafer, 10.20,30---Tape 2
, 11.21.31-m-flat surface, 12.22.
32-11, 13.23.33-11 gas chamber,
15.25.35---Gas vent. Figure 1A Figure 1C Figure 2A Figure 3A

Claims (1)

[Claims] 1. Wafer positioning characterized in that, on the flat surface of the table having a flat surface larger than the outer circumference of the wafer, a plurality of gas ejection holes are arranged on a circumference near the outer circumference of the wafer. table. 2. The wafer positioning table according to claim 1, wherein each of the gas ejection holes has a circular opening. 3. The wafer positioning table according to claim 1, wherein each of the gas ejection holes has a circular opening and is arranged in two rows on the circumference near the outer periphery of the wafer. 4. The wafer positioning table according to claim 1, wherein each of the gas ejection holes has a cocoon-shaped opening. 5. The wafer positioning table according to any one of claims 1 to 4, wherein a flange is formed on the peripheral edge of the flat surface.