JPH05299489A - Wafer transfer robot - Google Patents

Abstract

PURPOSE:To provide a finger structure of a wafer transfer robot, particularly of a hand portion thereof which enables chucking of a variety of wafer cassettes holding the hand at the predetermined height without relation to a kind of full-size type wafer cassette and half-size type wafer cassette. CONSTITUTION:In a hand 6 mounted on a wafer transfer robot to be used in the process treatment of a semiconductor wafer and provided with a pair of fingers 7 holding a wafer cassette from both right and left sides through the chucking to the ear portion of the cassette, the height is aligned with that of the full-size type wafer cassette 1 and the half-size type wafer cassette 2. The finger 7 is provided with two stages of upper and lower hook grooves 7a and 7b. While the hand is positioned at the same height, the full-size type wafer cassette 1 is chucked with the upper stage hook groove 7a, and the half- size type wafer cassette 2 is chucked with lower stage hook groove 7b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer transfer robot that transfers a semiconductor wafer in a cassette between a chemical treatment tank and a cleaning tank in a semiconductor wafer process step, particularly in a wet process step.

[0002]

2. Description of the Related Art As is well known, in a wet station for carrying out a wet treatment of semiconductor wafers, a semiconductor wafer is automatically conveyed by a robot handling operation between a chemical treatment bath and a cleaning bath which are arranged in the order of steps.
In this case, a predetermined number of semiconductor wafers are housed in a wafer cassette and transferred between processing steps. The wafer cassette used here is shown in FIG.
A full size type wafer cassette 1 or a half size type wafer cassette 2 as shown in (a) and (b) is used. 1a and 2a are handling ears protruding laterally from the upper edges of the cassettes 1 and 2, and 3 is a semiconductor wafer housed in the cassette.

Here, taking a wafer cassette applied to an 8-inch semiconductor wafer as an example, the dimensional standard is represented by specific numbers. In the full-size type wafer cassette 1 shown in FIG. Is 233.4 mm, and the height H1 is 219.07 mm. In the half-size type wafer cassette 2 shown in (b), the width is 234.7 mm and the height H2 is 1
It is 55.57 mm.

Next, FIG. 4 shows the structure of a conventionally used wafer transfer robot. That is, the robot has a carrier 4 that moves in the X-axis direction along a traveling route in the wet station by a chain drive mechanism, a vertical axis module 5 that moves in the Z-axis direction, and a vertical axis module 5.
And a pair of left and right hand arms 6a, 6b protruding from the hand 6 and having hook-shaped fingers 7 at the tips thereof.
Are attached one by one.

When the full-size type wafer cassette 1 is gripped and conveyed as shown in FIG.
First, the vertical axis module 5 is moved to position the height of the hand 6 so that the fingers 7 can access the height of the ears of the wafer cassette 1, and then the arm of the hand 6 is closed to move the wafer cassette 1 from the left and right sides. Chuck your ears. On the other hand, in the case of the half size type wafer cassette 2, as shown in FIG. 5B, the vertical axis module 5 is moved to move the hand 6 to a position lower than the position shown in FIG. I try to chuck my ears.

[0006]

By the way, the above-mentioned conventional wafer transfer robot has the following problems in terms of control when handling a wafer cassette. That is, when the semiconductor wafer 3 is transferred by randomly using the full size type wafer cassette 1 and the half size type wafer cassette 2 shown in FIG. 3 at the same wet station, the robot hand is moved to the height of the wafer cassette. In order to position them together, it is necessary to identify the type of wafer cassette each time. Therefore, conventionally, the heights corresponding to the wafer cassettes 1 and 2 are detected on the wafer cassette transfer line.
A sensor flow (eg photoelectric switch) is installed, and based on the identification signal detected here, the vertical movement module of the robot is positioned and controlled to a predetermined height, and the wafer cassette is chucked. It is the current situation.

However, performing the positioning control of the robot as described above every time the wafer cassette is chucked complicates the control system, and the tact time of the wafer process process becomes long because it takes time to position the robot. Throughput is also adversely affected. The present invention has been made in view of the above points, and an object thereof is to solve the above problems and hold a hand at a predetermined height position regardless of the types of a full size wafer cassette and a half size wafer cassette. Another object of the present invention is to provide a wafer transfer robot capable of accurately chucking various wafer cassettes, particularly a finger structure of its hand part.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the above object is to provide a finger of a hand part with two upper and lower hooks in accordance with a height difference between a full size type wafer cassette and a half size type wafer cassette. This is achieved by providing a section. Further, as an embodiment of the finger, the finger is made of a fluororesin plate, and a hook portion arranged in two steps on the plate surface of the finger is formed by groove processing.
Or make fingers with steel rods coated with fluororesin,
There is a configuration in which the steel rods are arranged in upper and lower two stages and attached to the tip of the hand.

[0009]

According to the above construction, regardless of the type of wafer cassette, when the robot hand is positioned at a predetermined height position with respect to the wafer cassette placed on the stage or the like and the hand arm is closed, the height becomes high. In the case of a full size type wafer cassette, the ear portion of the cassette is chucked by the hook portion on the upper side of the finger. On the other hand, in the case of a short half size type wafer cassette, it is chucked by the hooks on the lower side of the fingers. Therefore,
When handling the wafer cassette, it is not necessary to identify the type of the wafer cassette each time and to control the height positioning of the hand portion based on the identification result, which greatly simplifies the control of the robot.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings of each embodiment, the same members corresponding to those in FIGS. 4 and 5 are designated by the same reference numerals. Embodiment 1 In FIGS. 1 (a) and 1 (b), a pair of left and right fingers 7 attached to the tips of arms 6a and 6b of a hand 6 of a robot are provided with hook grooves 7a and 7b in upper and lower stages on the inner surface side. It is formed facing each other. The finger 7 is made of a corrosion-resistant fluororesin plate, and the hook grooves 7a and 7b are formed by cutting the plate surface. Here, the distance ΔH between the hook grooves 7a and 7b is
Height H1 of full-size wafer cassette 1 shown in FIG.
And the height difference H2 of the half size type wafer cassette 2 (H1−H2).

With this structure, when chucking a wafer cassette placed on a stage or the like, the hand 6 is used.
The arm 6a, 6 of the hand 6 by positioning the
Close b. Here, if the full-size wafer cassette 1 is placed as shown in FIG. 7A, the ear portion 1a of the cassette 1 is chucked in the upper hook groove 7a of the finger 7. On the other hand, if the half-size wafer cassette 2 is placed as shown in FIG. 3B, the lower hook groove 7b of the finger 7 chucks the ear 2a of the cassette 2. That is, regardless of the type of wafer cassette, the full-size type and half-size type wafer cassettes can be correctly chucked while the robot hand 6 is held at the same height position.

Embodiment 2 FIGS. 2A and 2B show an applied embodiment of the present invention. In this embodiment, rod-shaped fingers 8 and 9 are attached to the tip ends of the hand arms 6a and 6b in two steps, and each finger 8 and 9 has a fluorine-containing peripheral surface as shown in FIG. It is made of a stainless steel rod 11 covered with a resin (tube) 10. Here, the distance ΔH between the upper finger 8 and the lower finger 9 is set under the same condition as the distance between the hook grooves 7a and 7b described in the first embodiment.

Therefore, when the wafer cassette is gripped by the robot hand, the full-size type wafer cassette 1 has the ears on the fingers 8 on the upper stage side as shown in the figure with the hand 6 being positioned at a predetermined height. The half-size wafer cassette 2 is hooked and chucked, and the half-size wafer cassette 2 is chucked by the fingers 9 on the lower stage side. It should be noted that, since the fingers are made of a bar material, the fingers are lighter in weight as compared with the first embodiment, and there is an advantage that the cutting process of the fluororesin is unnecessary.

[0014]

As described above, according to the configuration of the present invention, when the wafer cassette is held by the hand of the transfer robot, the full-size type wafer cassette and the half-size wafer cassette are held while the hand is positioned and held at a predetermined height. The size type wafer cassette can be chucked correctly. Therefore, when using a full-size wafer cassette and a half-size wafer cassette in the same process line, it is not necessary to identify the wafer cassette type and control the positioning of the hand according to the cassette type, unlike the conventional transfer robot. As a result, the throughput of the wafer processing process can be improved as well as the simplification of the robot control.

[Brief description of drawings]

FIG. 1 is a configuration diagram corresponding to a first embodiment of the present invention,
(A) is a diagram showing a chucking state of a full size type wafer cassette, and (b) is a diagram showing a chucking state of a half size type wafer cassette.

FIG. 2 is a configuration diagram corresponding to Example 2 of the present invention,
(A) is a diagram showing a chucking state of a wafer cassette, and (b) is a structural diagram of fingers.

3A and 3B are views showing types of wafer cassettes used in a semiconductor wafer process step, wherein FIG. 3A is an outline drawing of a full-size wafer cassette, and FIG. 3B is an outline drawing of a half-size wafer cassette.

FIG. 4 is an overall configuration diagram of a conventional wafer transfer robot.

5A and 5B are explanatory views of chucking operation of a wafer cassette by the robot of FIG. 4, where FIG. 5A is a chucking state diagram of a full size type wafer cassette, and FIG. 5B is a chucking state diagram of a half size type wafer cassette.

[Explanation of symbols]

 1 Full size type wafer cassette 1a Ear part 2 Half size type wafer cassette 2a Ear part 3 Semiconductor wafer 6 Hand 7 Finger 7a Upper side hook groove 7b Lower side hook groove 8 Upper side finger 9 Lower side finger 10 Fluororesin 11 Steel rod

Claims (3)

[Claims] 1. A wafer transfer robot used in a semiconductor wafer process step, comprising a pair of fingers for chucking the wafer cassette from the left and right sides by chucking the cassette ear at the tip of a hand mounted on the robot. The wafer transfer robot according to claim 1, wherein the fingers are provided with upper and lower two-stage hook portions according to the height difference between the full-size wafer cassette and the half-size wafer cassette. 2. The wafer transfer robot according to claim 1, wherein the fingers are made of a fluororesin plate, and hook portions arranged in two rows above and below are grooved on the plate surface of the fingers. A wafer transfer robot. 3. The wafer transfer robot according to claim 1, wherein the fingers are made of a steel rod coated with fluororesin,
A wafer transfer robot, characterized in that the steel rods are arranged in two stages, one above the other and attached to the tip of a hand.