JP2000269311A - Wafer holding mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict dusts, and reliably fix a wafer to and detach from a hand by a method wherein a margin part of a wafer plane is pressed from both sides with a small force. SOLUTION: A wafer 10 is transfered by a process hand 46 in a predetermined posture during cleaning. The process hand 46 is constituted by a holder bracket 100 on which a margin part of a wafer plane abuts when grasping the wafer; and a holder can 110 for urging the margin part of the wafer 10 in a direction of a butting on the holder bracket 100 when receiving the wafer. Here, the holder can 110 (using a polyimide resin, etc., having little possibility of generating dusts) has a lever part 112 and a stage part 114 integral with each other, and is rotatably provided around a horizontal axis 108. The process hands 46 are arranged, for example, at four positions in an outer periphery of the wafer instead of holder pins, and the margin parts on an upper face and lower face of the wafer are pinched at four positions between a lower face of the holder bracket 100 and an upper face of the holder cam 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer gripping mechanism for a hand, and more particularly to a method for securely fixing and detaching a wafer, which is suitable for use in a process hand of a wafer cleaning apparatus using an aerosol. The present invention relates to a wafer gripping mechanism of a hand.

[0002]

2. Description of the Related Art Fine particles (particles) and dirt on the surface of a semiconductor wafer or the surface of a liquid crystal (LCD) or a solar cell in an LSI manufacturing process greatly reduce the yield of a final product. Surface cleaning is very important.

Therefore, various surface cleaning methods have been conventionally proposed. In the case of semiconductor production, for example, pure water cleaning using ultrasonic waves and chemical solutions (for example, ammonia hydrogen peroxide solution and sulfuric acid peroxide solution) in pure water are proposed. A wet cleaning method is used in which an object to be cleaned is immersed in a solution to which a (hydrogen solution) is added, and the object is cleaned.

However, this type of wet cleaning system is
There is a problem that the installation area of various facilities is large, and waste liquid treatment is required.

On the other hand, as a dry cleaning method using no liquid, there is dry cleaning using a chemical reaction by adding a gas, but there is a problem that contaminants on particles cannot be removed.

Further, it has been considered that particles such as dry ice, ice, and solid argon are made to collide with the surface of the object to be cleaned to remove particles. The surface may be damaged, and when dry ice is used, there is a problem of impurity contamination since dry ice itself is contaminated, especially in a commercial product using waste gas from steel or petroleum refinery.

On the other hand, Japanese Unexamined Patent Publication No.
And the method described in JP-A-6-295895, in which an aerosol containing argon solid fine particles (referred to as an argon aerosol) is collided in a reduced-pressure, zero-atmosphere atmosphere to clean the surface, the above problem does not exist. .

FIG. 1 is a pipeline diagram showing the overall structure of an example of a wafer cleaning apparatus using this argon aerosol, FIG. 2 is a plan view thereof, and FIG. 3 is a longitudinal sectional view of a cleaning chamber.

In this example, the argon gas and the nitrogen gas, the flow rates of which are controlled by the mass flow controllers 30 and 32, pass through a filter 34 and then enter, for example, a heat exchanger 38 using a helium (He) cryo refrigerator 36. After being cooled in the aerosol nozzle 20, the aerosol 24 is sprayed from a large number of fine nozzle holes 22 opened in the aerosol nozzle 20 into a cleaning chamber 42 for wafer cleaning, which is evacuated by the vacuum pump 40.

The wafer 10 is placed on a process hand (also referred to as an XY scan stage) 46 which is scanned in the X-axis direction and the Y-axis direction by a wafer scanning mechanism 44, and the entire surface of the wafer can be cleaned.

The acceleration nozzle 56 is used to improve the cleaning power.
Is supplied to the acceleration nozzle 56 via the mass flow controller 52 and the filter 54, and nitrogen gas (referred to as an acceleration gas 58) blown out from the nozzle hole is ejected from the aerosol nozzle 20. The aerosol 24 is accelerated.

For the purpose of preventing particles from re-adhering to the wafer surface, nitrogen gas flowing from one end (left end in FIG. 2) of the cleaning chamber 42 through the mass flow controller 62 and the filter 64 is used as a purge gas 66. Cleaning room 42
It is also considered to be supplied inside.

In FIG. 3, reference numeral 50 denotes a shield for controlling the flow of gas in the cleaning chamber 42.

As shown in FIG. 2, the two wafers 10 in the cassette chamber 70 which are evacuated to a vacuum state for loading the wafers 10 accommodated in the cassette 72 from outside of the apparatus are provided. A gate valve 74 is provided by a robot hand 86 attached to the tip of a robot arm 84 of a vacuum transfer robot (called a vacuum robot) 82 provided in a robot chamber (also referred to as a transfer chamber) 80 for handling the wafer 10. , 76 to transfer the wafer 10 to the cleaning chamber 42
0 is transferred onto the process hand 46.

The wafer 10 carried on the process hand 46 driven by the wafer scanning mechanism 44 is scanned in the Y-axis direction and the X-axis direction below the aerosol nozzle 20.

The wafer 10 whose entire surface has been cleaned in this way is returned to the cassette chamber 70 by following the path carried into the buffer chamber 90 in reverse.

In such an aerosol-based wafer cleaning apparatus, as shown in detail in FIG. 4, the process hand 46 pushes the edge of the wafer 10 from the side by, for example, four holder pins 48 set around the process hand 46. I was holding.

[0018]

However, with the improvement of the cleaning power, the flow of gas has become intense, and a trouble that the wafer 10 comes off the process hand 46 during cleaning has started to occur. Also, the round edge of the wafer 10 and the holder pin 4
Since the points 8 are in point contact, stress is concentrated on the edge of the wafer 10, and the edge is broken to generate particles.

The present invention has been made to solve the above-mentioned conventional problems, and has as its object to reduce the amount of dust generation, prevent the wafer from coming off even during handling in an intense gas flow, and to make sure that the wafer can be detached when the wafer is delivered. Make it an issue.

[0020]

SUMMARY OF THE INVENTION According to the present invention, in a wafer gripping mechanism of a hand for transferring a wafer and gripping the wafer in a predetermined posture, a peripheral edge of a wafer plane is brought into contact with the wafer when the wafer is gripped. A holder bracket and a holder cam that urges the peripheral portion of the wafer in a direction in which the wafer comes into contact with the holder bracket when receiving the wafer, so that the holder bracket and the holder cam sandwich the peripheral portion of the wafer plane from both sides. This has solved the above problems.

Further, the holder cam includes a rotating body which is rotated by an end face of the wafer when receiving the wafer.

Further, the holder cam may include a slope for moving a peripheral portion of the wafer in a direction of contacting the holder bracket when the wafer is received.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In the first embodiment of the present invention, as shown in FIG. 5, the wafer is transferred by the process hand 46 for transferring the wafer 10 and holding the wafer in a predetermined posture (horizontal in the embodiment) during wafer cleaning. The gripping mechanism includes a holder bracket 100 to which the peripheral edge of the wafer plane (upper surface in the figure) is in contact when the wafer is gripped, and a direction in which the peripheral edge of the wafer 10 contacts the holder bracket 100 when the wafer is received (in FIG. Holder cam 11 biasing upward)
And the holder brackets 10 are disposed at, for example, four locations on the outer periphery of the wafer in place of the holder pins.
The lower edge of the wafer 0 and the upper surface of the holder cam 110 sandwich the upper and lower peripheral edges of the wafer at four locations, for example, from above and below.

Since the holder bracket 100 is directly hit by the aerosol, a material resistant to the aerosol such as stainless steel or silicon can be used.

The holder cam 110 has a lever portion 112 and a stage portion 114 integrated with each other, and is rotatable around, for example, a horizontal shaft 108 held by a holder bracket 100. The holder cam 110 is preferably made of an organic material that generates less dust, for example, a polyimide resin.

Further, by using at least one of the holder brackets 100 or at least one of the holder cams 110 with a conductive material, it is possible to prevent a reduction in cleaning power due to electrostatic charging. If the holder bracket and the holder cam are all made of non-conductive material,
The gas may be ionized to prevent static electricity.

The operation will be described below.

When the wafer 10 is placed on the process hand 46 and the hand is closed, the wafer 10 is pushed rightward in the figure as shown by arrow A, and the edge of the wafer 10 is moved to the holder cam as shown by arrow B. 110 lever part 112,
It is rotated clockwise in the figure around the horizontal axis 108.
As a result, the stage 114 of the holder cam 110 lifts the peripheral edge of the wafer 10 upward as shown in the direction of arrow B, and vertically clamps the wafer 10 with the lower surface of the holder bracket 100.

On the other hand, when removing the wafer 10, the process hand 46 is opened. Then, the stage portion 114 of the holder cam 110 is pushed down in the drawing due to the weight of the wafer 10, and the holder cam 110 rotates counterclockwise in the drawing. As a result, the lever portion 11 of the holder cam 110
2 pushes the edge of the wafer 10 leftward in the drawing, and pushes the wafer 10 back to a position where the holder bracket 100 does not interfere when the wafer 10 is removed upward as shown by arrow C.

Next, a second embodiment having a simpler structure will be described in detail with reference to FIG.

In this embodiment, the holder cam 120 has a triangular prism shape having a slope 120S, and the holder bracket 1
It is different from the first embodiment in that it is fixed to 00.

In this embodiment, the process hand 4
6, the peripheral edge of the wafer 10 slides on the slope 120S of the holder cam 120 as shown by the arrow D,
The same operation as in the first embodiment is performed.

In the above-described embodiment, the present invention is applied to the process hand of the aerosol-based wafer cleaning apparatus so as to hold the wafer in a horizontal posture. The application target is not limited to this. For example, the application target may be held in a vertical posture or applied to a robot hand.

[0035]

According to the present invention, the round edge of the wafer is not held by point contact, but the peripheral edge of the wafer plane is held from both sides by surface contact with a small force, so that dust is generated. It is possible to securely fix the wafer to the hand with a small amount, and it is also possible to securely attach and detach the wafer.

[Brief description of the drawings]

FIG. 1 is a pipeline diagram showing an overall configuration of an aerosol-based wafer cleaning apparatus, which is an example of an object to which the present invention is applied.

FIG. 2 is a plan view of the same.

FIG. 3 is a sectional view of the same cleaning chamber.

FIG. 4 is a cross-sectional view showing a main part of a wafer gripping mechanism of a process hand used in the wafer cleaning apparatus.

FIG. 5 is a sectional view showing a first embodiment of a wafer gripping mechanism according to the present invention.

FIG. 6 is a sectional view showing a second embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wafer 42 ... Cleaning chamber 46 ... Process hand 100 ... Holder bracket 108 ... Horizontal axis 110, 120 ... Holder cam 112 ... Lever part 114 ... Stage part 120S ... Slope

Claims (3)

[Claims] 1. A wafer gripping mechanism of a hand for transferring a wafer and gripping the wafer in a predetermined posture, comprising: a holder bracket that abuts a peripheral portion of a wafer plane when the wafer is gripped; A wafer gripping mechanism for a hand, comprising: a holder cam for urging the peripheral portion of the wafer in a direction in which the peripheral portion comes into contact with the holder bracket, wherein the holder bracket and the holder cam sandwich the peripheral portion of the wafer plane from both sides. 2. The wafer holding mechanism according to claim 1, wherein said holder cam includes a rotating body which is rotated by an end face of said wafer when receiving said wafer. 3. The wafer gripping mechanism according to claim 1, wherein said holder cam includes a slope for moving a peripheral portion of said wafer in a direction of contacting said holder bracket when receiving a wafer.