JPH03238245A - Sample holder - Google Patents

Abstract

PURPOSE:To hold a fragile sample stably by providing a gas blowing passage, which is open to the almost center of the surface of a holder and inclined at 40 deg. or more and less than 90 deg., and a gas drawing port, which is open to the surface of the holder in the direction that blown gas proceeds to draw the blown gas therein. CONSTITUTION:A sample 2 is held by blowing gas from a blowing port 15 into a gap between the surface of the sample 2 to be held and the surface of a holder 11 which is installed on the opposite side adjacent to the surface thereof, and the held sample is led sideways and carried. In addition, a gas blowing passage 14 is provided which is open to the almost center of the surface of the holder and inclined at 40 deg. or more and less than 90 deg. to the surface. From this blowing passage into a gap between the sample 2 and the holder, gas is obliquely blown to hold the sample 2 in no contact with the holder and to pull the sample held in no contact therewith in the direction that the blown gas proceeds and carry the same while being stably held by the holder. The blown gas is drawn into a drawing port 16.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a method of spraying a gas such as N2 gas or air at high speed onto the surface of a sample such as a semiconductor wafer, which is easily damaged by contact. The present invention relates to a sample holding device that can be held in contact and transported horizontally, and more specifically, to a sample holding device that self-recovers blown gas.

[Prior Art] As an apparatus for transporting a sample such as a semiconductor wafer that is easily damaged by contact, an apparatus that holds the sample in a non-contact manner is desirable.

FIG. 5 is a cross-sectional view schematically showing the configuration of a main part of a conventional sample holding device that holds a sample in a non-contact manner. In the figure, reference numeral 1 denotes a disc-shaped holder, and the holder 1 holds a wafer 2. Wafer guides 3 are provided at multiple locations on the outer periphery of the lower end of the holder 1, protruding in the radial direction, with tips hanging down outside a position corresponding to the outer periphery of the wafer 2, and with the hanging tips protruding below the bottom surface of the holder 1. ,3. ... has been set up. Approximately in the center of the holding body l, N is supplied from a supply source (not shown).
A gas introduction pipe 4 for spraying gas, etc. onto the wafer 2 penetrates vertically from the upper surface to the lower surface of the holder 1, and the gas introduction pipe 4
The air outlet 5 opens on the lower surface of the holder 1.

The principle by which the wafer 2 is held in a non-contact manner by this sample holding device will be explained below. N2 gas, air, etc. are supplied to the gas introduction pipe 4 of the holder 1 disposed above and close to the wafer 2, and are blown at high speed onto the surface of the wafer 2 from the outlet 5.

The blown high-speed gas is guided into the gap between the holder 1 and the wafer 2, as indicated by arrows in the figure, and flows radially along the surface of the wafer 2. Since the gas flows back through the gap at high speed, the gas pressure in the gap between the wafer 2 and the holder 1 increases
The pressure becomes negative from the atmospheric pressure below, and an upward force acts on the wafer 2 due to the pressure difference between the upper and lower sides of the wafer 2, causing the wafer 2 to approach the holder 1. When the wafer 2 approaches the holder 1, the gap between the holder 1 and the wafer 2 narrows, so the gas pressure in the gap increases, and a downward force is applied to the wafer 2. The wafer 2 is suspended and held in a non-contact manner with the holder 1 maintaining a gap between the wafer 2 and the holder 1 that balances the three forces: an upward force, a downward force applied to the wafer 2, and the weight of the wafer 2.

Further, the wafer 2 is moved horizontally by moving the holder 1 horizontally with the outer peripheral edge of the wafer 2, which is movably held suspended by the balance of vertical forces, in contact with the wafer guide 3 fixed to the holder 1. 2 in the horizontal direction and stop it at the stop position.

However, since the wafer 2 moves in the horizontal direction only by being pushed by the wafer guide 4, the wafer guide 4 collides with the outer edge of the wafer 2 many times during transportation, especially when starting and stopping, causing the wafer edge to collapse. It may cause scratches or cracks.

Such a sample holding device that avoids collision between the wafer guide and the wafer is such that the gas introduction tube is tilted against the lower surface of the holder, and the wafer is hit against the wafer guide with gas blown onto the wafer from an oblique direction. A device that horizontally transports the wafer with the wafer in contact with the wafer guide (US Patent N
o, 3.523.706) or a device provided with both a gas introduction tube for blowing gas in an oblique direction and a gas introduction tube for blowing gas in a vertical direction (U.S. Pat. No. 3.539.216).
) has been devised.

Although the above-described device can avoid collision of the wafer guide with the wafer, if gas is blown in an oblique direction, the blown gas will blow out from the gap between the holder and the wafer. If the gas blows out at high speed, external dust may be kicked up and adhere to adjacent wafers, or external dust may enter the gap from the opposite side of the gas direction, causing damage to the wafers that are being held in a non-contact manner. becomes easier to adhere to.

As described above, the presence of dust on the wafer causes deterioration of the M quality during film formation on the wafer.

As a device for preventing gas from flowing in and out between the gap between the holder and the wafer and the outside, a device has been devised that is equipped with a means for collecting the gas blown out from the outlet by the holder itself ( JP-A-62-251094). By maintaining a balance between the gas blowout flow rate and the suction flow rate in this device, it is possible to prevent gas from flowing in and out between the gap between the holder and the wafer and the outside.

[Problem to be solved by the invention]

By the way, the above-mentioned requirements such as holding the wafer in a non-contact manner in a stable state both vertically and horizontally, preventing damage to the wafer, and preventing gas from entering and exiting between the gap and the outside are met. An ideal sample holding device that satisfies these requirements cannot be achieved by simply combining a gas introduction pipe that blows gas in an oblique direction and a suction port that recovers the blown gas. In other words, when gas is blown in in an oblique direction, the gas flow becomes asymmetric between the direction in which the gas flows and the opposite side, making it difficult to recover the entire amount of gas on the opposite side. In this case, localized gas ingress and egress is likely to occur, as in the case where outside air is more likely to enter. Furthermore, if the gas flow becomes asymmetrical, it is difficult to stably hold the wafer.

The present invention was made to solve such problems, and by appropriately setting the position of the gas inlet, the inclination of the gas introduction path, and the position of the inlet of the blown gas, It stably holds the sample vertically and horizontally without contact to prevent damage to the sample, and
An object of the present invention is to provide a sample holding device that can reduce the adhesion of dust to an evaporator by preventing gas from entering and exiting between the sample and the holder.

[Means for Solving the Problems] The sample holding device of the present invention holds the sample by blowing gas into the gap between the surface of the sample to be held and the surface of a holder disposed opposite to the surface. In addition, in a sample holding device that guides and transports a held sample in a lateral direction, a gas blowing path that opens approximately at the center of the surface of the holder and is inclined at an angle of 40° or more and less than 90° with respect to the surface. and a suction port that is open on the surface of the holder portion in the direction toward which the blown gas is directed, and that sucks in the blown gas.

[Effect]

The sample holding device of the present invention blows gas diagonally from the blowing path into the gap between the sample and the holder, holds the holder in a non-contact manner, and moves the sample held in a non-contact direction in the direction in which the blown gas heads. It is transported while being held stably by the holding body.

Further, the blown gas is sucked in through the suction port provided in the direction in which the gas is directed, and no gas is allowed to enter or exit between the outside and the gap.

[Example] Hereinafter, the present invention will be explained based on drawings showing examples thereof.

FIG. 1 is a plan view showing the configuration of the main parts of the sample holding device of the present invention, and FIG. 2 is a sectional view taken along the line ■-■ in FIG.
1 holds wafer 2. On the outer periphery of the lower side of the holding body 11,
A bottle-shaped wafer guide 13.13. protrudes outward from a position corresponding to the outer circumference of the wafer 2 and has a hanging tip. ... are arranged in six equal numbers. The tips of the hanging portions of the wafer guides 13, 13, . . . reach below the lower surface of the holder 11. The wafer guide 13 stops its horizontal movement so that the wafer 2, which is pushed toward the wafer guide 13 by the blown gas, does not exceed the range where the wafer 2 can be suspended and held by the holder 11.

At approximately the center of the holder 11, a gas introduction passage 14 for blowing gas supplied from a supply source (not shown) into the gap between the holder 11 and the wafer 2 penetrates from the upper surface to the lower surface of the holder 11. The passage 14 is inclined at an angle θ (40°≦θ<90°) with respect to the lower surface of the holder 11, and the center of the outlet 15 is a point eccentric from the center of the holder 11 by a distance @R (R55 m).

A suction groove 16 for trapping the blown gas is provided along the outer periphery of the holder 11.

The suction groove 16 has a suction groove 16 located at an angle ψ (-90"≦ψ≦90°) with the approximate center of the direction in which the gas blown out from the blowout port 15 heads as a reference (0°).
An exhaust port 17 is provided for discharging the gas above the holding body 11.

A flow meter (not shown) is provided on the inlet side of the gas introduction path 14.

conductance valve, gas supply source is connected,
A flow meter, a conductance valve, and a pump (not shown) are connected to the outlet side of the exhaust port 17.

Based on these measured values, the flow rate of the gas blown out from the blowout port 14 and the flow rate of the suction gas recovered from the suction groove 16 via the exhaust port 17 to the pump are adjusted so as to be equal.

In this embodiment, a case has been described in which one exhaust port 17 is provided, but a plurality of exhaust ports 17 may be provided as long as it is within the range of -900≦ψ≦90'. In that case, it is desirable to provide the plurality of exhaust ports 17 approximately symmetrically with respect to the center in the direction in which the gas is directed.

In the case of a wafer with a diameter of about 6 inches, if the eccentricity R of the air outlet 15 exceeds the above condition (R≦5), the vertical upward force acting on the center of the wafer 2 becomes small. The wafer 2 vibrates or moves erratically, making non-contact holding unstable.

If the inclination θ of the gas introduction path 14 is made smaller to reduce the inclination from the air outlet 15, the force for moving the wafer 2 in the horizontal direction becomes stronger.
If the angle is smaller than the range of 0°), the gas will be blown in concentratedly at one location, making it difficult to completely recover the gas.

When the exhaust port 17 is provided in a direction in which the angle ψ from the center of the holder 11 exceeds the above-mentioned condition (-90°≦ψ≦90°), that is, in the opposite direction to the direction in which the gas is directed, In this case, gas blows out to the outside, and in the opposite direction, air from outside enters. In addition, the flow of gas becomes complicated because the blown gas collides with the gas sucked into the exhaust port 17, which is the direction opposite to the direction in which the gas is heading.
It becomes impossible to move the wafer 2 toward the wafer guide 13.

Next, as shown in the plan view of FIG. 3 and the cross-sectional view of FIG. The results of holding the 6-inch wafer 2 by the sample holding device with the condition that the angle of the exhaust port 17 from the center of the sample is ψ−0° will be explained based on a specific numerical example.

The holder 11 was brought close to a position 2g from the top surface of the wafer 2, and N2 gas was introduced into the outlet 15 so that the average flow velocity inside the outlet 15 was 50 m/s.
A gas flow rate equal to the introduced flow rate of the two gases is exhausted from the exhaust port 17 by the pump. The wafer 2 is held suspended from the lower surface of the holder 11 with a gap h=o, 16 mm, and is guided in the direction in which the obliquely blown N2 gas is directed, pressed against the wafer guide 13, and moved horizontally. movement is stopped. At this time, even if the wafer 2 moved the holder 11 vertically and horizontally, the wafer 2 maintained its relative position with the holder 11 and followed the movement of the holder 11.

Measurement using a hot wire anemometer showed that almost no gas was blown out or sucked in from the gap between the holder 11 and the wafer 2, and the wind speed was at a so-called bank ground level of 0.02 m/s or less.

Note that the conditions for eccentricity R9, blowout angle θ, and exhaust port angle ψ are R≦5ma+, 40°≦θ≦90°, 90°≦
If ψ≦90° is satisfied, results similar to those described above can be obtained.

Further, in this embodiment, a case has been described in which one blow-off port 15 is provided, but a plurality of blow-off ports 15 may be provided as long as the amount of eccentricity R from the center of the holder is satisfied.

[Effects of the Invention] As described above, the sample holding device of the present invention stably holds fragile samples such as semiconductor wafers without contact, and also allows the sample to be moved laterally by the flow of gas blown in an oblique direction. Since the sample is transported in a state where it is stably held in the holder, the sample is not damaged.Furthermore, the blown gas is collected from the suction port provided in the direction in which the gas is directed, and the gas between the outside and the gap is removed. This has the excellent effect of preventing dust from adhering to the sample and not stirring up dust from the environment in which the device is installed.

[Brief explanation of drawings]

1 and 3 are plan views showing the configuration of main parts of the sample holding device of the present invention, FIG. 2 is a cross-sectional view taken from the line ■-■ in FIG. FIG. 5 is a sectional view taken along the line, and is a sectional view schematically showing the configuration of main parts of a conventional sample holding device. 2... Wafer 11... Holder 13... Wafer guide 14... Gas introduction path 15... Air outlet
16...Suction groove 17...Exhaust port

Claims (1)

[Claims] 1. Hold the sample by blowing gas into the gap between the surface of the sample to be held and the surface of a holder placed opposite the surface, and move the held sample laterally. A sample holding device for guiding and transporting a sample, comprising: a gas blowing path that opens approximately at the center of the surface of the holding body and is inclined at an angle of 40° or more but less than 90° with respect to the surface; and a direction in which the blown gas is directed. A sample holding device comprising: a suction port that is open to the surface of the holding body portion and sucks in the blown gas.