JPH04267355A - Wafer conveying robot - Google Patents

Abstract

PURPOSE:To provide a wafer conveying robot which does not produce dust or oil mist detrimental to the wafer and which is not influenced by the temperature or the degree of vacuum at a place where the wafer is processed. CONSTITUTION:A wafer conveying arm 10 comprises arm driving magnets 4, 5 disposed on the outside of a vacuum chamber R and magnetically coupled with parts composed of magnetic materials 11, 12 thus driving the parts, means 1 for rotating the arm driving magnets 4, 5 around a vertical axis C, and means for driving straight the arm driving magnets 4, 5. Since the wafer can be conveyed to a predetermined position without producing dust or chips detrimental to the wafer and without requiring a magnetic fluid seal which may cause gas leak, the wafer conveying robot can be operated even under a relatively high temperature environment or high vacuum environment. Furthermore, reduction in size and weight can be realized easily because power supply into the vacuum chamber is not required.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a robot that operates in a reduced pressure room (vacuum chamber) or a clean room, and more specifically, the present invention relates to a robot that operates in a reduced pressure room (vacuum chamber) or a clean room. The present invention relates to a manipulator or wafer transfer robot that can perform

0002

2. Description of the Related Art Semiconductor chips or wafers, for example, are processed in a clean room because if dirt, oil mist, etc. adhere to them during the manufacturing stage, the yield will deteriorate due to so-called particle contamination and productivity will deteriorate. Furthermore, since the manufacturing process is often performed in a vacuum, the transfer of wafers within the manufacturing equipment is performed in a vacuum by a robot. Here, a conventional example of a robot for transferring wafers is shown in FIG.

In FIG. 2, the wafer transfer robot is
It is roughly composed of a driving section 50 provided in the atmosphere A and a handling section 60 provided in the vacuum chamber V. The drive unit 50 is provided with a first motor M1 and a second motor M2, and an output shaft 51 of the first motor M1.
is connected to a vertical hollow drive shaft 62. On the other hand, the output shaft 52 of the second motor M2 is connected to a small drive shaft 63 provided within the hollow drive shaft 62. Therefore,
When these motors M1 and M2 rotate, the drive shaft 6
2 and 63 are rotated by a predetermined amount in a predetermined direction.

A first horizontal arm 64 is fixed to the upper end of the hollow drive shaft 62, and a second horizontal arm 65 is rotatably provided at the tip thereof. On the other hand, the small drive shaft 6
A pulley 66 is fixed to the upper end of the pulley 66.
A belt 67 is passed around between the pulley (not shown) provided at the pivot point of the second arm 65 and a pulley (not shown). Therefore, when the belt 67 is driven, the second
The arm 65 is rotationally driven with respect to the first arm 64.

When the motor M1 is rotated by a predetermined amount in a predetermined direction, the hollow drive shaft 62 rotates, and the first arm 64, which is integrally fixed to the hollow drive shaft 62, also rotates in a horizontal plane as shown by arrow a. move. Therefore, the second arm 65 also rotates integrally, and the hand 68 attached to the tip of the second arm 65 rotates integrally.
The upper wafer (not shown in FIG. 2) is transferred to a predetermined angular position in the horizontal plane. On the other hand, when the motor M2 is driven, the small drive shaft 63 is driven, and the second arm 65 is connected to the pulley 6.
6. The first arm 64 is driven within a predetermined angular range in a horizontal plane by a belt 67 as shown by arrow b. As a result, a wafer (not shown) on the hand 68 can be transferred radially inward or outward by a predetermined amount.

[0006] If relatively rotating members are mechanically supported, particulates are generated from the parts and contaminate the wafer. Therefore, in conventional robots, magnetic fluid seals are also installed on the bearings to prevent dust generation. Further, the motor and the vacuum chamber are sealed by an O-ring, and the drive shafts 62 and 63 passing through the atmosphere side and the vacuum side are sealed by magnetic fluid seals.

[0007]

[Problems to be solved by the invention] However, with the magnetic fluid seals used in the conventional robots mentioned above, gas is generated when the vacuum is reduced to, for example, about 10-6 Torr, and the generated gas contaminates the wafer. There is a problem that the yield rate deteriorates.

[0008] Furthermore, the magnetic fluid seal has an operating temperature of 0.
There is also the problem that the temperature is relatively narrow at about ~80°C.

The present invention has been proposed in view of the problems of the prior art described above, and is capable of transporting wafers within a clean room or vacuum chamber, while also preventing harmful dust, oil mist, etc. from being generated on the wafers. The purpose of the present invention is to provide a wafer transfer robot that does not cause any problems and is not affected by the operating temperature or the degree of vacuum at the location where it is used.

0010

[Means for Solving the Problems] A wafer transfer robot of the present invention includes a wafer transfer arm that moves a wafer horizontally and linearly, and a vacuum chamber that accommodates the wafer and the wafer transfer arm. The wafer transfer arm includes a portion made of a magnetic material, and includes an arm driving magnet that is disposed outside the vacuum chamber and magnetically couples with and drives the portion made of the magnetic material. , a rotation means for rotating the arm drive magnet around a vertical axis, and a linear drive means for linearly moving the arm drive magnet.

In carrying out the present invention, it is preferable that the magnet provided outside the vacuum chamber, ie, the arm driving magnet, be an electromagnet. Preferably, the electromagnet includes a sensor that detects the distance between the partition wall of the vacuum chamber and the wafer transfer arm, and a control unit that controls the current supplied to the electromagnet in response to the output from the sensor.

[0012] Here, it is possible to provide a permanent magnet as the arm driving magnet, but in that case, it is necessary to provide means for maintaining the distance between the partition wall of the vacuum chamber and the wafer transfer arm within a predetermined range.

[0013] There are no particular restrictions on the number of arm-driving magnets and their mounting positions, but they should be configured so that they do not interfere with the processing equipment adjacent to the wafer transfer robot and the arm can move as long as possible. is preferred.

[0014] Furthermore, it is preferable that a portion (target) made of a magnetic material in the wafer transfer arm be provided at a position corresponding to the arm driving magnet.

[0015] Furthermore, it is preferable that a wafer holding hand is attached to the tip of the arm, and the wafer is placed on the hand or detachably held.

[0016]

[Operation] Since the present invention is constructed as described above, the arm driving magnet is rotated by a predetermined amount in a predetermined direction by the rotating means. Then, the wafer transfer arm also rotates by a predetermined amount around the vertical axis (rotation axis). Next, the arm driving magnet is moved by a predetermined amount in the linear direction by the linear driving means. As a result, the wafer transfer arm moves linearly by a predetermined amount.

As a result, the wafer placed on or detachably attached to the tip of the arm can be transferred to a predetermined position in the horizontal plane.

On the contrary, the arm driving magnet may first be moved by a predetermined amount in a linear direction by the linear drive means, and then rotated by a predetermined amount in a predetermined direction by the rotation means. Furthermore, it is also possible to transfer the wafer by performing linear movement and rotation at the same time.

In this way, by appropriately setting the amount of rotation by the rotation means and the amount of linear movement by the linear movement means,
A wafer on a hand attached to, for example, the tip of the arm can be transferred to a desired position.

[0020] In the present invention, since the arm is supported in a non-contact manner by magnetic attraction, fine particles (dust) may be generated when the arm is rotated by the rotation means and linearly moved by the linear movement means. There is no. Furthermore, since no magnetic fluid seal is used, the operating temperature range is wide, and no gas is generated even under extremely high vacuum conditions.

[0021] As a result, contamination of the wafer is prevented and the yield in manufacturing semiconductor integrated circuits is improved.

In addition, according to the present invention, there is no need to supply power to the inside of the vacuum chamber, so the structure is simplified;
It is easy to reduce the size and weight, and there is no problem of heat accumulation on the vacuum side. In other words, since the arm driving magnet (consisting of an electromagnet), the rotation means, and the linear movement means are all arranged outside the vacuum chamber, power can be easily supplied.

[0023]

[Embodiment] Hereinafter, one embodiment of the present invention will be explained in detail with reference to FIG. The robot of the first embodiment includes a wafer transfer arm 10 placed in a vacuum chamber R.

The arm driving magnets 4 and 5 are composed of electromagnets, which are supplied with current through a control means (not shown) and are attached to a rotation means indicated by the reference numeral 1. This rotating means 1 is configured to be rotationally driven (rotated) by, for example, a step motor 2 around a vertical axis C by a predetermined amount in a predetermined direction.

Two magnetic materials 11 and 12 are provided below the arm driving magnets 4 and 5 with a relatively thin partition wall 3 in between, and are magnetically coupled to the magnets 4 and 5. Note that, as is clear from FIG. 1, the magnetic materials 11 and 12 constitute a part of the wafer transfer arm 10.

These magnets 4 and 5 and magnetic materials 11 and 12
It is opposite to. When the rotating means 1 and the arm driving magnets 4 and 5 rotate (rotate) about the axis C, the magnetic materials 11 and 12 also rotate, and the entire arm 10 rotates around the rotating means 1.
It rotates by the same amount in the same direction.

However, in the direction indicated by arrow Y in FIG. 1, it is driven independently of the rotation means 1 by a linear drive means (not shown).

The wafer transfer arm 10 has a rod-like shape. The magnetic material 1 described above is attached to one end of the magnetic material 1.
1 and 12 are provided, and a hand 13 is detachably attached to the other end, and a wafer 14 is placed on this hand.

The wafer transfer arm 10 is held in a floating state within a vacuum chamber R partitioned by a partition wall 3 and a fixing member 20. The distance between the partition wall 3, which is a partition wall of the vacuum chamber R, and the arm 10 is measured by a sensor (not shown).

The magnetic materials 11 and 12 are provided at a predetermined interval, and a wafer transfer arm 10 is located at the center of the magnetic materials 11 and 12.
A counterweight 15 is provided at the left end of the arm in the drawing so that the center of gravity of the arm is located. Since the center of gravity is aligned with the center in this manner, the wafer transfer arm 10 is supported horizontally by the magnetic materials 11 and 12 without strain while maintaining moment balance within the vacuum chamber. Although the weight of the wafer 14 is extremely small and can be ignored, the counterweight can also be determined by considering the weight of the wafer.

Next, the operation of the above embodiment will be explained. When transferring the wafer 14 on the wafer transfer arm 10 in the direction of arrow Y, the magnets 4 and 5 are appropriately driven by linear movement means (not shown). As mentioned above, the magnetic materials 11, 1
2 is magnetically coupled with the magnets 4 and 5, so the magnet 4
, 5 move in the Y direction, the arm 10 and wafer 14 are also transferred to a predetermined position in the Y direction.

When changing the direction of linear movement, motor 2
is driven to rotate the rotating means 1 and the arm driving magnets 4 and 5 by a predetermined amount in a predetermined direction. As a result, the magnetic materials 11 and 12 and the arm 10 also rotate about the axis C. As a result, the wafer 14 on the arm 10 is positioned in a predetermined direction.

In this way, the wafer 14 can be transferred to any position within the plane, but the same effect can be obtained even if the rotation means 1 and the linear movement means (not shown) are driven in the opposite order to the above explanation, or even if they are driven simultaneously. It is clear that it affects

According to this embodiment, the wafer transfer arm 1
Since the counterweight 15 is attached to the 0, the magnetic bodies 11 and 12 (or two magnetic bearings) are provided at the ends of the arm 10, but since they are sandwiched between the center of gravity of the arm 10, The wafer transfer arm 10 can be supported without difficulty in a state where the moments are also balanced.

The arm 10 is maintained in a floating state by the arm driving magnets 4 and 5 based on the output of the sensor described above.
By providing a control unit (not shown) that adjusts the current supplied to the arm 10, the distance between the partition wall 3 and the arm 10 is controlled to be within a certain range of values.

Note that when the tip of the wafer transfer arm 10, that is, the part on which the wafer 14 is placed, exits the vacuum chamber R, a gate valve is provided at the exit, and the gate valve is opened and closed to maintain an airtight state. arm 10 can be taken out to the outside.

Although not shown, the present invention can be implemented in various modifications. For example, the number of magnets and the driving magnets that cooperate with (magnetically couple with) the magnets may be three or more. However, the drawings only show an embodiment in which the arm driving magnet is provided above the vacuum chamber and two magnetic bodies are provided.

[0038]

As described in detail above, according to the present invention, the wafer transfer arm is supported in a vacuum chamber by a magnetic bearing in a non-contact manner, and is driven from the outside by a driving magnet in a non-contact manner. Therefore, there is no mechanical contact with the vacuum chamber, and the wafer can be transferred to a predetermined location without generating harmful dust or dirt on the wafer.

[0039] Furthermore, unlike conventional magnetic fluid seals, there is no need for a magnetic fluid seal, so there is no gas generation, and the device can be used even under relatively high temperature or high vacuum environments.

Furthermore, since the driving magnet rotates together with the arm driving magnet and is driven independently and linearly, the wafer can be transferred to any position within the horizontal plane.

Furthermore, there is no need to supply current inside the vacuum chamber. Therefore, there are no structural restrictions regarding the current supply means, which simplifies the configuration and greatly increases the degree of freedom in design. Accordingly, it becomes extremely easy to reduce the size and weight, and the manufacturing cost can also be kept low.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view showing one embodiment of the present invention.

FIG. 2 is a perspective view showing a conventional example.

[Explanation of symbols]

1... Rotating means 3...Partition wall 4, 5...Arm drive magnet 10...Wafer transfer arm 11, 12...magnetic material R...vacuum chamber C...Vertical axis

Claims (1)

[Claims] 1. A wafer transfer arm that moves a wafer horizontally and linearly, and a vacuum chamber that accommodates the wafer and the wafer transfer arm, the wafer transfer arm being made of a magnetic material. an arm driving magnet disposed outside the vacuum chamber and magnetically coupled to and driving the part made of a magnetic material, the arm driving magnet being arranged around a vertical axis; A wafer transfer robot comprising: a rotation means for rotating the arm; and a linear drive means for linearly moving the arm driving magnet.