JPH08195427A - Conveyance mechanism - Google Patents

Abstract

PURPOSE: To realize a conveyance mechanism of a sample such as a wafer or the like, which can reduce the volume of a sample replacement chamber and shorten the time for the replacement of the sample. CONSTITUTION: A second lever 11 and a third lever 27 are installed at both ends of a first lever 7 which is turned by a drive source 22. In addition, setting plates 15, 24 are installed at the second and third levers, the second and third levers are turned by turning the first lever, and the first and second setting plates are turned by turning the second and third levers. As a result, the first and second setting plates 15, 24 are moved with a sample mounted. In addition, the first and second setting plates are arranged so as to be separated in theup- and-down direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer transfer mechanism suitable for use in an electron beam drawing apparatus and a semiconductor wafer inspection apparatus.

[0002]

2. Description of the Related Art In a semiconductor wafer inspection apparatus using an electron beam drawing apparatus or a scanning electron microscope, a drawing chamber and a sample chamber evacuated to a vacuum and a sample exchange chamber connected to the sample chamber are provided. Transfer wafers, mask substrates, etc. In this case, the sample chamber and the sample exchange chamber are partitioned by a sluice valve, and in the initial state, the sluice valve is closed,
The sample exchange chamber is set to atmospheric pressure, and in that state, a sample to be inspected or drawn, for example, a wafer is inserted into the exchange chamber.

After that, the sample exchange chamber is evacuated to a vacuum, and after a predetermined degree of vacuum is reached, the sluice valve is opened and the wafer in the sample exchange chamber is transferred into the sample chamber. After the wafer is placed at a predetermined position in the sample chamber, the sluice valve is closed, and drawing or inspection using an electron beam on the wafer is executed in the sample chamber. Meanwhile, the inside of the sample exchange chamber is again brought to atmospheric pressure, a new wafer is inserted, and the chamber is evacuated to a vacuum. After completing the prescribed drawing and inspection on the first wafer,
The sluice valve is opened, and the wafer that has undergone the inspection and the like is exchanged with a new wafer in the sample exchange chamber. Wafers are sequentially processed in such steps.

A mechanism for transporting the wafer is required for the above-mentioned wafer exchange, and an element required for this mechanism is a sample exchange chamber (preliminary exhaust chamber) in order to maintain a good throughput. The first is to minimize the volume of the. Therefore, as a conventional transfer mechanism, a mechanism that uses one arm to supply and discharge the wafer is generally used. In addition, a method of incorporating two arms or placing two wafers on both ends of the arms at the same time and supplying or discharging the wafers by rotating the arms is also widely used.

[0005]

In the method using one arm described above, there is practically enough space for moving the wafer and the transfer arm, and a shifter for raising and lowering the wafer accompanying it. It suffices if there is space for other mechanisms such as. Therefore, there is an advantage that the exhaust volume can be extremely reduced and the exhaust time can be significantly shortened. However, in the case of one arm, since the supply and the discharge of the wafer are performed in one continuous operation, there is a drawback that it takes time to replace the wafer, and as a result, the throughput is not always excellent. .

On the other hand, the method of incorporating two arms requires a lot of space, the volume of the sample exchange chamber increases, and the evacuation time becomes long. Also, in the method of rotating the arm, since the arm rotates in an arc shape,
That alone requires a large sample exchange room.

The present invention has been made in view of the above points, and an object thereof is to reduce the volume of a sample exchange chamber,
Another object is to realize a mechanism for transporting a sample such as a wafer that can shorten the time required for sample exchange.

[0008]

According to the present invention, a transport mechanism is provided with a first lever which is rotated by a drive source and a first lever which is engaged with one end of the first lever and rotates with the first lever. A second lever that rotates, a third lever that engages with the other end of the first lever and that rotates with the rotation of the first lever, and a second lever that engages with the other end of the second lever The first setting plate that rotates with the rotation of the lever and places the sample on it, and the first setting plate that engages with the other end of the third lever and that rotates with the rotation of the third lever, place the sample on it. Equipped with a second setting plate,
First lever and second lever and first lever and third
The rotation ratio of the second lever to the first setting plate and the rotation ratio of the third lever to the second setting plate are 2: 1 respectively.
It is characterized in that the first and second setting plates are arranged separately in the vertical direction.

[0009]

In the carrying mechanism of the present invention, the first and second setting plates are vertically spaced apart from each other, and a sample such as a wafer is carried on the setting plate and carried. The two types of setting plates and samples do not collide.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of a carrying mechanism according to an embodiment of the present invention, and FIG. 2 is a plan view showing a part of the carrying mechanism.
In the figure, reference numeral 1 is a sample chamber, and if it is an electron beam writer, it is not shown as a drawing chamber, but an electron gun, a focusing lens, an electron optical system such as an electron beam deflection system, etc. It has an electron beam column. A sample exchange chamber 2 is attached to the side surface of the sample chamber 1. An opening 3 for transferring a wafer is provided between the sample chamber 1 and the sample exchange chamber 2.
Is opened, and a sluice valve 4 is provided in this opening. The interiors of the sample chamber 1 and the sample exchange chamber 2 are configured to be evacuated to a vacuum by an exhaust unit (not shown).

A cylindrical shaft 5 is provided on the base of the sample exchange chamber 2.
Is fixed, and a central portion of a first lever 7 that rotates about the shaft 5 is attached to the shaft 5 via a bearing 6. A pulley 8 is integrally provided on the upper portion of the shaft 5. In addition, pins are implanted (fixed) at both rotary ends of the first lever 7, the second lever 11 is rotatably attached to one pin (first pin) via a bearing, and the other pin is attached. A third lever 27 is rotatably attached to the (second pin) via a bearing. Second lever 11 and third
The respective cylindrical portions below the lever 27 form a pulley 9 and a pulley 25, respectively. The pulley 12 is integrally formed on the upper part of the first pin, and the pulley 28 is integrally formed on the upper part of the second pin. A belt 10 and a belt 26 are wound around the pulley 8 and the pulleys 9 and 25, respectively. The pulley diameters are selected so that the rotation ratio between the pulley 8 and the pulleys 9 and 25 is 1: 2.

A third pin and a fourth pin are planted (fixed) at the respective rotary ends of the second lever 11 and the third lever 27. The setting plate 15 is rotatably attached to the third pin via a bearing, and the setting plate 24 is rotatably attached to the fourth pin via a bearing. The cylindrical portions below the setting plates 15 and 24 are pulleys 1 respectively.
3, the pulley 29 is formed. Pulley 12 and pulley 1
A belt 14 is wound between the pulleys 3 and 3, and a belt 30 is wound between the pulleys 28 and 29. The rotation ratio between the pulleys 12, 28 and the pulleys 13, 29 is 2: 1.
Thus, the pulleys 13 and 29 have twice the pitch diameter of the pulleys 12 and 28. It should be noted that the wafer 16 as a conveyed product is placed on the setting plates 15 and 24.

A shifter 17 for moving the wafer 16 up and down is provided on the upper portion of the shaft 5, and the shifter 17 is fixed to a shifter shaft 18 which vertically moves through a central hole of the shaft 5. Has been done. The vertical movement mechanism of the shifter shaft 18 is not shown. The lower cylindrical portion of the first lever 7 forms a pulley 19, and a belt 20 is wound around the pulley 19 and the pulley 21. The pulley 21 is rotated by a drive source 22 such as a motor or a rotary actuator. Although a sluice valve 23 is provided in a part of the sample exchange chamber 2, the sluice valve 23 is provided for supplying the wafer 16 to the exchange chamber 2 and discharging it.

A sample moving stage 31 is movably arranged in the sample chamber 1, on which a wafer 16 is placed, and processing such as drawing is performed. The stage 31 is provided with a shifter 32 for vertically moving the wafer 16. The setting plates 15 and 24
Are so arranged as to be vertically separated from each other so that the wafers 16 placed on them do not interfere with each other, that is, they do not collide with each other due to the movement of the setting plates 15 and 24. This configuration is achieved by making the pulleys 13 and 29 different in height. In addition, in FIG. 1, the shape of the setting plate 24 is shown schematically. Next, the operation of such a configuration will be described.

First, when the pulley 21 is rotated by the drive source 22, the rotation is transmitted to the pulley 19 by the belt 20. As a result, the first lever 7 rotates, the rotation angle α of the first lever 7 changes, and the pulleys 9 and 25 rotate according to the change of the rotation angle α, and the second lever 1
1, the 3rd lever 27 rotates. Second lever 11, third
When the lever 27 rotates, the pulleys 13 and 29 rotate,
The setting plates 15 and 24 rotate. Pulley 9
Rotates at a rotation angle twice as large as the rotation of the first lever 7 and returns to the original angle by the pulley 13. Therefore, the setting plate 15 always has the base of the isosceles triangle whose one side is the distance between the axes of the second lever 11. Becomes

Similarly, since the pulley 25 rotates at a rotation angle twice the rotation of the first lever 7 and returns to the original angle by the pulley 29, the setting plate 24 always keeps the axial distance of the third lever 27. It is the base of an isosceles triangle with one side. Here, since the inter-axis distance of the second lever 11 and the inter-axis distance of the third lever 27 are shorter than the turning radius corresponding to that of the first lever 7, respectively, the setting plate 1
5, 24 are always parallel to the axis of their direction of travel, but coincide on-axis at the ends of their travel. That is, when the rotation angle α of the first lever 7 is 90 °, it is furthest from the axis. Therefore, at this time, the setting plates 15 and 2
4 are the furthest apart from each other. That is, the farthest distance can be maintained when the two are in positions where they should interfere with each other.

Next, steps for carrying the wafer 16 will be described with reference to FIG. For simplification of the explanation, it is assumed that the wafer 16 is present in the sample chamber 1 at first (though it is basically the same even if there is no wafer 16). At this time, the gate valve 4 is in the closed state, and the rotation angle α of the first lever 7 is stopped at the position of 90 °. This state is shown in FIG.
In this state, the wafer 16 on the side of the sample chamber 1 is placed on the moving stage 31, and drawing, observation, or inspection such as length measurement is performed at a predetermined position.

During this time, the sluice valve 23 is opened, and a new wafer 16 is supplied from the outside of the sample exchange chamber 2. The new wafer 16 is lifted by the shifter 17 in the central portion of the first lever 7 to a height at which the shifter 17 and the wafer 16 are not interfered by the setting plates 15 and 24 (do not collide) and are on standby. At this time, the gate valve 23 is closed and the inside of the sample exchange chamber 2 is evacuated.

When the predetermined work in the sample chamber 1 is completed,
The stage 31 moves to the sample exchange position in the sample chamber 1, the sluice valve 4 is opened, and the shifter 32 on the stage 31 raises the wafer 16.

Next, the drive source 22 causes the first lever 7 to move to α =
Rotate 180 ° to set the setting plate 15,
Advance and retract 24 respectively. This state is shown in Figure 3.
Shown in (b) and (c). When α becomes 180 °, the shifters 17 and 32 descend, and the wafer 16 is placed on the setting plates 15 and 24, respectively. This state is shown in FIG.

Next, the first lever 7 is reversed (α = 0 ° direction) and the positions of the respective wafers are retracted. This state is shown in FIGS. When α is 0 °, the shifters 17 and 32 are lifted to lift the wafer 16. This state is shown in FIG. Next, the first lever 7 is returned to the position of α = 90 °, the sluice valve 4 is closed, and gas is introduced into the exchange chamber 2 until the sample exchange chamber 2 becomes atmospheric pressure. This state is shown in FIGS.
And shown in FIG. The steps described above are repeated, and the state is shown in FIGS. Note that FIG.
The state of (l) returns to the state of FIG.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this embodiment. For example, the wafer transfer has been described as an example, but the present invention can be applied to other samples such as a mask substrate. Further, the shape of the setting plate is not limited to the illustrated one. Furthermore, in the above embodiment, the combination of the pulley and the belt is used for transmitting the rotation, but a timing belt that does not cause slippage is preferable as this belt. In addition to this configuration, a combination of gears and idle gears may be used.

[0023]

As described above, in the transport mechanism of the present invention, the second and third levers are provided at both ends of the first lever, and the setting plates are provided on the second and third levers. The second and third levers are rotated by the rotation of the first lever, and the first and second setting plates are vertically separated from each other, and a sample such as a wafer is placed on the setting plate and conveyed. It was constructed so that the seed setting plate and the sample did not collide. Therefore, two samples can be simultaneously supplied and discharged in a small space both vertically and horizontally, and the supply and discharge time can be greatly shortened. Further, the volume of the sample exchange chamber can be reduced and the exhaust time can be shortened.

Further, the turning radii of the second lever and the third lever are appropriately shortened as compared with the turning radius of the first lever, and the sample such as the wafer is moved in a slightly arcuate shape, and the second and third levers are moved.
By avoiding the interference between the lever and the setting plate, it is possible to minimize the vertical distance when the two samples rub each other. Therefore, the stroke of the shifter is small, and the supporting mechanism of the shifter and the surrounding mechanism can be made compact as a whole.

[Brief description of drawings]

FIG. 1 is a side view of a transport mechanism that is an embodiment of the present invention.

FIG. 2 is a plan view of a part of the transport mechanism of FIG.

FIG. 3 is a diagram for explaining a moving operation of a setting plate.

FIG. 4 is a diagram for explaining a moving operation of a setting plate.

[Explanation of symbols]

 1 sample chamber 2 sample exchange chamber 7 first lever 11 second lever 15,24 setting plate 16 wafer 17 shifter 27 third lever

Claims (1)

[Claims] 1. A first lever that is rotated by a drive source, a second lever that is engaged with one end of the first lever and that rotates with the rotation of the first lever, and a first lever other than the first lever. The third lever is engaged with the end and rotates with the rotation of the first lever, and the third lever is engaged with the other end of the second lever and rotates with the rotation of the second lever, and the sample is placed on the third lever. A first setting plate which is engaged with the other end of the third lever, and a second setting plate which is engaged with the other end of the third lever and rotates with the rotation of the third lever to place the sample thereon. The rotation ratio of the lever to the second lever and the first lever to the third lever is 1: 2, and the second lever and the first setting plate and the third lever and the second setting plate are The rotation ratio of each is set to 2: 1. The second setting plate is a transport mechanism configured to be vertically spaced apart.