JP7371662B2 - Wafer transfer device - Google Patents

Description

The present invention relates to a wafer transfer device that transfers wafers to and from an electrostatic chuck.

When the wafer is removed from the electrostatic chuck, the stress applied to the wafer during wafer processing is released all at once, causing the wafer to bounce. Additionally, if there is a resist film on the backside of the wafer, gas released from the resist film during wafer processing will accumulate between the wafer and the electrostatic chuck, making the wafer bounce even more when the wafer is removed. become.

As a countermeasure against wafer bouncing, Patent Document 1 discloses that while an elastically supported pin is pressed against the top surface of the wafer, the adsorption voltage of the electrostatic chuck is turned off to remove the wafer from the electrostatic chuck. There is.

JP2015-15330

Although it is possible to prevent the wafer from bouncing by pressing the pins against it, there is a concern that the wafer may be displaced in its radial direction due to the impact upon detachment.
If the positional deviation of the wafer in the radial direction is large, problems such as the wafer falling off may occur during transportation after the wafer is delivered.

Therefore, a wafer transfer device is provided that can not only suppress the bouncing of the wafer when the wafer is removed, but also suppress the positional shift in the radial direction of the wafer.

The wafer transfer device is
A transport arm;
a wafer support member that is attached to the transfer arm and supports the lower end of the wafer during wafer transfer;
a wafer holding pin that comes into contact with the top surface of the wafer when the wafer is removed from the electrostatic chuck;
and a guide member positioned on the side of the wafer when the wafer is removed from the electrostatic chuck.

With the wafer transfer device having the above configuration, the wafer holding pin can hold down the top surface of the wafer, and the guide member can prevent the wafer from shifting in the radial direction. It becomes possible to suppress both the bouncing of the wafer and the positional shift in the radial direction of the wafer.

Preferably, the wafer holding pin and the guide member are attached to the transfer arm.

If the wafer holding pin and the guide member are attached to the transfer arm, these members will not interfere with wafer processing. Furthermore, since the member is not exposed to ion beams, plasma, etc. during wafer processing, the life of the member can be extended.

Preferably, the guide member has an inclined surface that faces a side surface of the wafer when the wafer is removed from the electrostatic chuck.

With the above configuration, it is possible to more reliably suppress positional deviation in the radial direction of the wafer when the wafer is removed.

The guide member has a top plate having an outer shape larger than the outer shape of the wafer, and a position regulating portion protruding downward from the top plate.

With the above configuration, positional displacement in the wafer radial direction can be easily suppressed at multiple positions in the wafer circumferential direction. Furthermore, maintenance related to attaching and detaching the guide member becomes easier.

The top plate has a notch,
It is preferable that the wafer holding pin protrudes downward from the transfer arm through the notch.

With the above configuration, the wafer holding pin and the guide member can be attached and removed independently. Further, it is possible to reduce the size in the height direction of the member used for regulating the position of the wafer.

The wafer is a ribbed wafer with ribs on the peripheral edge,
It is preferable that the wafer holding pin is arranged at a position corresponding to a rib of the wafer.

The ribbed portion is provided to ensure the rigidity of the wafer, and the ribbed portion of the ribbed wafer is eventually removed. Therefore, even if the rib portion is damaged, it will hardly affect the manufacturing process in the middle.

While holding down the top surface of the wafer with the wafer holding pin, the guide member can prevent the wafer from shifting in the radial direction of the wafer, which prevents the wafer from bouncing when the wafer is removed from the electrostatic chuck and the position of the wafer in the radial direction. It becomes possible to suppress both deviations.

A plan view showing an example of the configuration of an ion implanter equipped with a wafer transfer device. A plan view showing an example of the configuration of a wafer transfer device Cross-sectional view taken along line AA shown in Figure 2 Enlarged view of the main parts of the broken line C section shown in Figure 3 Modified example of position regulation part Explanatory diagram for handling ribbed wafers A plan view showing another configuration example of the wafer transfer device Cross-sectional view taken along line BB shown in Figure 7 Enlarged view of main parts showing another configuration example of the wafer transfer device

FIG. 1 is a plan view showing an example of the configuration of an ion implanter IM equipped with a wafer transfer device H. The ion implanter IM extracts a spot-shaped ion beam IB from an ion source 11 and passes it through an analysis electromagnet 12 and an analysis slit 13 to analyze unnecessary ions contained in the ion beam.
After mass analysis, the ion beam IB is scanned in one direction by a magnetic field or electric field scanner 14, and the traveling direction of the ion beam IB is aligned in one direction by passing through the collimator magnet 15, and the ion beam IB is sent as a parallel ion beam IB to the processing chamber. Introduced on 16th.

In the processing chamber 16, the wafer W supported on the platen P is mechanically scanned by a drive mechanism (not shown) across the ion beam IB toward the back of the drawing, thereby performing ion implantation processing on the wafer W. Ru.

The wafer W is transported within the processing chamber 16 using a wafer transport device H. Specifically, the wafer transfer device H has two transfer arms 1 that can rotate independently. The two independently rotatable transfer arms 1 are provided with a wafer support member 2 that supports the outer peripheral edge of the wafer W at their lower ends.
The wafer W is transferred between the vacuum preliminary chamber 17 and the platen P by the wafer transfer device H using a drive mechanism (not shown) to rotate the transfer arm 1 in the direction of the arrow shown in the ZX plane. .

When transferring the wafer W to the platen P, the platen P is rotated by a rotation mechanism (not shown) about the X direction in the figure as a rotation axis, so that the wafer gripping surface of the platen P that grips the wafer W faces upward.
Note that the platen P includes an electrostatic chuck (not shown) for suctioning and supporting the wafer W.

When the processed wafer W is transferred from the platen P, the wafer gripping surface of the platen P faces upward, and one of the transfer arms 1 is rotated and placed above it.
Thereafter, the platen P moves in the Y direction with respect to the transfer arm 1, and the wafer W held on the platen P is in contact with the wafer holding pin and guide member on the transfer arm 1 (not shown), and the electrostatic chuck The suction of the wafer W is stopped.
Detaching a wafer from an electrostatic chuck, which will be described later in the present invention, refers to stopping or decreasing the suction voltage of the wafer W, and changing the suction voltage to remove the processed wafer from the electrostatic chuck. It refers to the operation when

The specific configuration of the wafer transfer device H will be explained using FIGS. 2 to 4. FIG. 3 is a cross-sectional view taken along line AA shown in FIG. The wafer support member 2 depicted by a broken line is arranged at a different position on the opposite side to the X direction from the illustrated transfer arm 1.

FIG. 2 is a plan view when one of the transfer arms 1 of the wafer transfer device H is moved to the position of the platen P in FIG. 1 and the transfer arm 1 is viewed from above. The wafer transfer device H includes a transfer arm 1 and a wafer support member 2 that is attached to the transfer arm 1 and supports the lower end of the wafer during wafer transfer.
Similar to FIG. 4, which will be described later, the wafer is drawn with a dashed-dot line so that the positional relationship with the wafer W can be seen when the wafer is removed from the electrostatic chuck.

The wafer support member 2 is a member similar to the substrate receiving part provided below the transfer arm disclosed in Patent Document 1, and is attached below the transfer arm 1 (on the opposite side to the Y direction) as shown in FIG. The wafer is a member having a step provided at its end to support the lower end of the wafer.

The wafer transfer device H further includes a wafer holding pin 3 and a guide member 4. The wafer holding pin 3 is a member that is pressed against the upper surface of the wafer at four locations, for example, as shown in FIG. It is indirectly attached to the transport arm 1. The wafer holding pin 3 is made of a material such as silicon or carbon. As in Patent Document 1, it is biased downward (to the side opposite to the Y direction) by a coil spring, a plate spring, etc. that are not shown.

The guide member 4 is fixed to the transport arm 1 below the transport arm 1, as shown in FIG. Further, the guide member 4 has a top plate 41 having an outer shape larger than the outer shape of the wafer W, as shown in FIG. It should be noted that the outer shape of the top plate 41 referred to here refers to the outer shape at a location excluding a notch, which will be described later. Simply put, the top plate 41 having an outer shape larger than the outer shape of the wafer W means that the top plate 41 covers the upper surface of the wafer W except for a notch portion to be described later.
Further, as illustrated in FIG. 3, the top plate 41 has a position regulating portion 42 extending downward from the periphery of the top plate 41. This position regulating portion 42 is provided along the periphery of the top plate 41. Further, the position regulating portion 42 has an inclined surface 43. This inclined surface 43 faces the side surface of the wafer W when the wafer is removed from the electrostatic chuck, as shown in FIG. 4, which will be described later.

A notch 44 shown in FIG. 2 is formed in the top plate 41. As shown in FIG. The wafer holding pin 3 projects downward from the transfer arm 1 (in the direction opposite to the Y direction) through this notch 44 . With this configuration, the wafer holding pin 3 and the guide member 4 can be attached and detached independently, and maintainability is improved.
Further, it is possible to reduce the dimensions in the height direction (Y direction) of the members used for regulating the position of the wafer (wafer holding pin 3 and guide member 4).

FIG. 4 is an enlarged view of the main part of the part surrounded by the broken line C shown in FIG.
When the wafer W is removed from the electrostatic chuck, the wafer holding pin 3 is in contact with the upper surface of the wafer W. Further, in the radial direction (Z direction) of the circular wafer W, the inclined surface 43 of the position regulating portion 42 extending from the top plate 41 is in contact with the wafer W. Note that the inclined surface 43 is curved in the circumferential direction of the top plate 41.

When the wafer W is in the state shown in FIG. 4 with respect to the wafer holding pin 3 and the position regulating part 42, removing the wafer W from the electrostatic chuck prevents bouncing of the wafer W and misalignment in the radial direction of the wafer. It becomes possible to suppress both.

Various changes can be made to the embodiments described above without departing from the spirit of the invention.

For the position regulating section 42, for example, the configuration shown in FIG. 5 may be adopted. FIG. 5 is an enlarged view of the main parts similar to FIG. 4. In FIG. 5, the position regulating portion 42 extends perpendicularly from the top plate 41 and does not have the inclined surface 43 shown in FIG. 4. Even if the position regulating portion 42 not having the inclined surface 43 shown in FIG. 5 is employed, it is possible to suppress the positional shift of the wafer W in the radial direction.
However, in the sense of further reducing the radial positional deviation of the wafer W, it is preferable to adopt a configuration having an inclined surface 43 shown in FIG. 4.

Before removing the wafer W from the electrostatic chuck, the platen P is moved upward (in the Y direction). When moving the platen P, in order to avoid physical interference between the platen P and the position regulating section 42, it is difficult to make the gap G between the side surface of the wafer W and the position regulating section 42 zero. . For this reason, it is necessary to provide some gap G between the wafer W and the position regulating portion 42, and there is a risk that the wafer W will be displaced in the radial direction by this gap G.

FIG. 6 shows how the ribbed wafer is removed from the electrostatic chuck. Ribbed wafers are known as wafers in which ribs are formed on the outer periphery of the wafer in order to provide rigidity to a very thin wafer.
In the semiconductor manufacturing process, the rib portion of a ribbed wafer is eventually removed, so even if the rib portion is damaged, it hardly affects the manufacturing process in the middle. For this reason, in FIG. 6, the wafer holding pin 3 is arranged so that the wafer holding pin 3 comes into contact with the rib portion.

In addition, the number of wafer holding pins 3 is not limited to four, but may be one or more. Preferably, the pins are arranged symmetrically with respect to the center of the wafer to be transferred, so that the upper surface of the wafer W can be pressed evenly.

The position regulating portion 42 does not need to be provided all around the top plate 41 except for the notch 44, and may be provided partially.
Further, the guide member 4 does not need to be composed of the top plate 41 and the position regulating part 42, and may be composed only of a rod-shaped or plate-shaped member extending downward from the transport arm 1. In addition, the configurations shown in FIGS. 7 and 8 may be used.

FIG. 7 is a plan view showing another configuration example of the wafer transfer device H. FIG. 8 is a cross-sectional view taken along line BB shown in FIG. Here, only the differences from the configuration explained in FIGS. 2 to 4 will be explained.

In FIGS. 7 and 8, a position regulating portion 42 is provided on a member that attaches the wafer support member 2 to the transfer arm 1. With this configuration as well, positional deviation in the wafer radial direction can be suppressed. Furthermore, since there is no top plate 41, there is an advantage in that the cost of parts is reduced accordingly.

However, rather than attaching a plurality of independent guide members 4 to the transfer arm 1, it is better to use the guide member 4 composed of the top plate 41 and the position regulating part 42 described in the previous embodiments. The workability associated with installation and position adjustment is greatly improved. Further, by adopting a configuration using the top plate 41, it is possible to suppress positional deviation in the wafer radial direction at a location spaced apart from the transfer arm 1 in the X direction.

Although the top plate 41 has a cutout 44 for inserting the wafer holding pin 3, the top plate 41 may have a cutout or a hole for other purposes.
For example, in order to detect the position of the wafer from above the transfer arm 1 with a sensor, a hole for detecting the wafer position may be formed in the top plate 41. Moreover, in order to avoid physical interference between the two independently rotatable transfer arms 1 shown in FIG. 1, a notch may be formed in the top plate 41.
The outer shape of the top plate 41 is preferably circular like the outer shape of the wafer, but may be rectangular or elliptical.

In the above embodiment, the wafer holding pin 3 and the guide member 4 are attached to the transfer arm 1, but the guide member 4 may be attached to the platen P.
However, if the guide member 4 is attached to the platen P, there is a concern that the processing of the wafer W supported by the platen P may be adversely affected. For example, in the ion implanter IM shown in FIG. 1, if the wafer holding pin 3 is longer than the thickness of the wafer W, when the platen P is tilted, a shadow of the pin will be formed on the wafer surface, and the ion implantation will be partially performed. This may cause problems such as not being able to be implemented. Further, if the wafer holding pin 3 is provided on the platen P, the wafer holding pin 3 will be exposed to ion beams, plasma, etc. during wafer processing, resulting in a problem that the life of the wafer holding pin 3 will be shortened.

Although the wafer holding pin 3 and the guide member 4 are indirectly attached to the transfer arm 1 in this configuration, it is also possible to have a configuration in which these members are directly attached to the transfer arm 1 without preparing any attachment members. .
Further, as shown in the enlarged view of the main part in FIG. 9, the wafer holding pin 3 may be attached to a member below the transfer arm 1 to which the wafer support member 2 is attached, similarly to the position regulating section 42.

The inclined surface 43 of the position regulating part 42 may face either upward or downward, but considering that the platen P moves from below to upward, the inclined surface 43 should face downward in the figure (in the Y direction). It is desirable that the surface be tilted toward the opposite direction of gravity.

In the above embodiment, the configuration of the wafer transfer device H is described using two independent transfer arms 1 as an example, but the number of transfer arms 1 may be one. Further, instead of the configuration in which the transport arm 1 is rotated within the ZX plane, it may be changed to a configuration in which it moves in a linear direction depending on the device configuration.

In the embodiment described above, the position regulating part 42 protrudes downward from the periphery of the top plate 41, but the position regulating part 42 protrudes downward from a location other than the periphery of the top plate 41, specifically, from a location on the center side from the periphery. A configuration may be adopted in which the position regulating portion 42 protrudes.

In addition, it goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made without departing from the spirit thereof.

H Wafer transfer device 1 Transfer arm 2 Wafer support member 3 Wafer holding pin 4 Guide member 41 Top plate 42 Position regulating portion 43 Inclined surface P Platen

Claims (5)

A transport arm;
a wafer support member that is attached to the transfer arm and supports the lower end of the wafer during wafer transfer;
a wafer holding pin that comes into contact with the top surface of the wafer when the wafer is removed from the electrostatic chuck;
a guide member positioned on the side of the wafer when the wafer is removed from the electrostatic chuck ;
The wafer is a ribbed wafer having ribs on the peripheral edge,
In the wafer transfer device , the wafer holding pin is arranged at a position corresponding to a rib of the wafer . The wafer transfer apparatus according to claim 1, wherein the wafer holding pin and the guide member are attached to the transfer arm. 3. The wafer transfer device according to claim 1, wherein the guide member has an inclined surface that faces a side surface of the wafer when the wafer is removed from the electrostatic chuck. The wafer transfer according to any one of claims 1 to 3, wherein the guide member has a top plate having an outer diameter larger than the outer diameter of the wafer, and a position regulating portion protruding downward from the top plate. Device. The top plate has a notch,
5. The wafer transfer apparatus according to claim 4, wherein the wafer holding pin projects downwardly from the transfer arm through the notch.