JP4027580B2 - Charged particle beam equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a sample holder, a sample exchange chamber (preliminary exhaust chamber), and a sample chamber for mounting a plate-like sample such as a semiconductor wafer when using an apparatus such as an inspection apparatus, a processing apparatus or a drawing apparatus using a charged particle beam. And a charged particle beam apparatus.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as a semiconductor wafer has become larger in diameter and finer in pattern, an electrostatic chuck device using electrostatic attraction force for a wafer inspection device using a charged particle beam such as a scanning electron microscope (SEM). Has become extremely useful. That is, in the SEM in which the resolution is increased to the limit to cope with the miniaturization of the pattern, the depth of focus is small, so that the surface of the sample is required to be sufficiently flat. However, in a recent semiconductor wafer having a thin sample and a large diameter, the surface of the sample is not sufficiently flat if the sample is simply placed and fixed on the sample stage. In such a case, if an electrostatic chuck device is used, flattening is facilitated.
[0003]
In addition, the method of inserting the sample into the device after loading the sample into the sample holder is only necessary to replace the sample holder when using a material other than the specified shape as the sample, which greatly expands the application range. It is a convenient way. In this case, however, it is naturally necessary to incorporate the electrostatic chuck device on the sample holder side.
[0004]
However, the electrostatic chuck device has a weak point. In other words, electrostatic dust adsorption and sample detachment may be difficult. Also, if the electrostatic chuck device is not built directly into the sample chamber, but is built into the sample holder, cleaning of the adsorbed dust and maintenance of the electrostatic chuck device will be easier, but the sample exchange chamber In the sample exchange chamber where the vacuum chuck is frequently evacuated and vented, the dust is likely to rise and the dust is attracted by the electrostatic chuck. There is a problem such as high possibility of being adsorbed on the surface.
[0005]
[Problems to be solved by the invention]
The present invention has been made to solve the above-mentioned problems, avoids the problem of connection with the electrostatic chuck power source while incorporating the electrostatic chuck device on the sample holder side, and further prevents electrostatic dust adsorption. The purpose is to reduce and facilitate the removal of the sample.
[0006]
[Means for Solving the Problems]
The charged particle beam apparatus of the present invention is a charged particle beam apparatus comprising: a sample exchange chamber; and a sample chamber for loading a sample holder for loading a plate-like sample of a semiconductor wafer through the sample exchange chamber. Includes: an electrostatic chuck device; a power receiving terminal means for the electrostatic chuck device; a reference portion for defining the position of the sample; and pressing the sample against the reference portion for positioning, and maintaining the position A means for driving the drive section, and means for supplying power to the electrostatic chuck device via the power receiving terminal means. It is provided with.
[0007]
In addition , the charged particle beam apparatus of the present invention further includes a tiltable sample lift means that allows the sample holder to fall with the sample placed in a direction driven by the drive unit. The retractable sample lift means is interlocked with the drive unit.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0011]
1 to 6 show an example of an embodiment of a sample holder and a sample holder mechanism of the present invention. FIG. 1 is a plan view of the sample holder, and FIG. 2 is a cross-sectional view. FIG. 3 is a diagram for explaining the details of the portion. Further, FIG. 4 is a diagram for explaining the relationship between the configuration of the sample exchange chamber (preliminary exhaust chamber) and the sample holder and the operation. FIG. 5 is a diagram for explaining the relationship and operation of the configuration of the sample chamber and the sample holder. FIG. 6 is a diagram for explaining the relationship among the sample chamber, the sample exchange chamber, and the sample transport device.
[0012]
In FIG. 6, 10 is a sample exchange chamber (preliminary exhaust chamber), and 20 is a sample chamber for inspecting, processing or drawing the sample W. 6 will be described later.
[0013]
1 and 2, W is a semiconductor wafer sample, 1 is a sample holder, 2 is an electrostatic chuck, and is a donut type having a hole in the center. Reference numeral 3 denotes a lift through-hole through which a lift (described later) that supports the sample W penetrates the sample holder 1 and the electrostatic chuck 2 when the sample W is attached to and detached from the sample holder 1, and 4 is a reference for positioning the sample W Pins 5 are drive pins for positioning and holding the sample 1, 6 are contacts for applying a desired voltage to the electrostatic chuck 2, and 7 is a reference surface of the sample holder 1.
[0014]
The drive pin 5 is attached to a U-shaped plate 5b as shown in FIG. 3A, and the plate 5b is moved in the direction of the reference pin 4 by a spring 5d as shown in FIGS. 3A and 3B. A force is given, and further, there is a claw 5a as shown in FIG. Further, as shown in FIG. 1, the sample holder 1 has a through hole 1 a so that the drive pin 5 protrudes from the upper surface of the sample holder 1. In FIG. 1, 8 is a retractable auxiliary lift. The auxiliary lift 8 passes through the through hole 1b opened in the sample holder 1 in FIG. 1 and the tip (the head 8a in FIGS. 3C and 3D) protrudes from the upper surface of the sample holder 1. It has become. As shown in FIG. 3 (c), the auxiliary lift 8 has 8b as a fulcrum, and a force is applied by the spring 8c so that the sample W is tilted in the direction in which the sample W is driven by the drive pin 5. The head 8 a is lower than the upper surface of the electrostatic chuck 2. 8 d is a driving material for the auxiliary lift 8. When the driving member 8d is driven in the direction of the arrow (not shown, the driving member 8d is connected to the plate 5b and moves simultaneously with the driving of the claw 5a of FIG. 3B), the auxiliary lift 8 rises. The head 8 a is set higher than the upper surface of the electrostatic chuck 2. FIG. 3D shows a modification of the retractable auxiliary lift. However, in this case, the driving direction of 8d is opposite to that in FIG.
[0015]
Further, in FIG. 4A, 11 is a sample holder mounting base in the sample exchange chamber 10, 12 is a positioning pin for positioning the sample holder 1, 13 is a drive pin for positioning the sample holder 1, and an arrow When driven in this direction, the sample holder 1 is positioned and fixed. 14 a is a lift that passes through the lift through hole 3 and moves the sample W up and down. Reference numeral 14 denotes a lift driving device for driving the lift 14a up and down. In FIG. 4B, 15a is a driving material for driving the claw 5a, 15 is a driving pin driving device for driving the driving pin 5 via the driving material 15a and the claw 5a, and the driving material 15a is moved in the direction of the arrow. , The drive pin 5 is driven in the direction of the arrow through the claw 5a, and the holding of the sample W is released. When the driving pin driving device 15 is driven to drive the driving member 15a in the direction opposite to the arrow, the sample W is pressed against the reference pin 4 by the action of the spring 5d.
[0016]
Further, in FIG. 5, reference numeral 21 denotes a sample stage in the sample chamber, which can move and drive the sample W to a desired position. Reference numeral 22 denotes a positioning pin of the sample holder 1, and 23 denotes a driving pin for positioning and holding the sample holder 1, and when driven in the direction of the arrow, the sample holder 1 is positioned and fixed. Reference numeral 24 denotes a contact on the sample stage 21 side for applying a desired voltage to the electrostatic chuck 2. When the sample holder 1 is positioned and fixed, the contact 5 and the contact 24 are connected.
[0017]
In FIG. 6, 50 is a wafer storage container, 51 is a sample transfer apparatus for transferring the wafer sample 1 from the wafer storage container 50 to the sample exchange chamber (preliminary exhaust chamber) 10 of the inspection apparatus, and 52 is in the sample exchange chamber 10. A gate valve 53 for vacuuming the outside of the apparatus and taking in and out the sample W is also a gate valve between the sample chamber 21 and the sample exchange chamber 11. Reference numeral 54 denotes a charged particle beam optical system for inspecting, processing or drawing the sample W.
[0018]
The operation of such a configuration will be described next.
[0019]
First, the case of mounting the sample W will be described. The gate valve 53 between the sample chamber 20 and the sample exchange chamber (preliminary exhaust chamber) 10 is closed, the inside of the sample exchange chamber 10 is brought to atmospheric pressure by a vacuum vent valve (not shown), and further, the sample exchange chamber 10 and the outside of the apparatus are connected. The gate valve 52 is opened. At this time, the sample holder 1 mounted on the sample holder mounting base 11 is at a predetermined position determined by the positioning pin 12 and the drive pin 13, and the lift 14a is at an upper position (the upper surface of the lift 14a is electrostatically charged). The upper surface of the chuck 2 and a position higher than the head 8a when the auxiliary lift 8 is standing up), and the sample W is not on the lift 14a.
[0020]
Next, a sample W such as a wafer is taken out from the wafer storage container 50 by the sample transport device 51 and placed on the lift 14a. When the sample W is placed on the lift 14a, the gate valve 52 between the sample exchange chamber 10 and the sample transport device 51 is closed and separated in a vacuum state, and the inside of the sample exchange chamber 10 is removed by a vacuum exhaust device (not shown). The atmosphere is exhausted, and the sample exchange chamber 10 is evacuated.
[0021]
The lift 14 a on which the sample W is placed is lowered downward by the lift driving device 14 provided on the sample holder platform 11, and the sample W is placed on the head 8 a of the auxiliary lift 8. Further, the driving pin driving device 15 provided on the sample holder placing table 11 drives the driving pin 5 so that the sample W is positioned so as to be pressed against the reference pin 4 and does not move in the horizontal direction. Will be held. At this time, the auxiliary lift 8 is also tilted in the direction of the reference pin 4, and the sample W riding on the head 8 a of the auxiliary lift 8 is smoothly pressed and positioned on the reference pin 4 side.
[0022]
When the sample W is positioned, the driving pin 13 is driven in a direction opposite to the positioning pin 12 by a driving device (not shown), and the fixing of the sample holder 1 is released. Next, the gate valve 53 between the sample chamber 20 and the sample exchange chamber 10 is opened, and the sample holder 1 is moved and loaded from the sample holder platform 11 to the sample stage 21 by a sample holder moving device (not shown). . Subsequently, when the driving pin 23 is driven in the direction of the positioning pin 22 by a driving device (not shown), the driving pin 23 is positioned so that the reference surface 7 of the sample holder 1 is pressed against the positioning pin 22. Then, when the sample holder 1 is positioned and fixed, the contact 6 provided on the sample holder 1 and the contact 24 provided on the sample stage 21 are connected, and a desired voltage is applied to the electrostatic chuck 2. The electrostatic chuck 2 obtains an adsorption force and adsorbs the sample W on the surface of the electrostatic chuck 2.
[0023]
After this, the desired location on the sample W is inspected if it is a wafer inspection apparatus, processed if it is a processing apparatus, and drawn if it is a drawing apparatus.
[0024]
Next, the case of detaching the sample W will be described. First, the gate valve 52 between the sample exchange chamber 10 and the outside of the apparatus is closed, the inside of the sample exchange chamber 10 is evacuated, and the gate valve 53 between the sample exchange chamber 10 and the sample chamber 20 is opened. Then, a driving device (not shown) is driven to move the driving pin 23 in the direction opposite to the positioning pin 22 to loosen it so that the sample holder 1 can be detached. 1 is moved from the sample stage 21 to the sample holder platform 11. With this operation, the contact 6 provided on the sample holder 1 and the contact 24 provided on the sample stage 21 are separated, and the electrostatic chuck 2 loses the attracting force. Next, a driving device (not shown) of the driving pin 13 is driven to drive the driving pin 13 in the direction of the positioning pin 12 to position and fix the sample holder 1. Subsequently, when the driving device 15 drives the driving pin 5 in the direction opposite to the reference pin 4, the driving pin 5 is separated from the sample W, and the auxiliary lift 8 that has fallen rises through 8d, and the head 8a. Thus, the sample W is surely detached from the electrostatic chuck 2 and the sample W is also separated from the reference pin 4. Subsequently, the lift 14a is lifted upward by the lift driving device 14, and the gate valve 53 between the sample chamber 20 and the sample exchange chamber 10 is closed in parallel or before and after this.
[0025]
When the gate valve 52 is closed, the sample exchange chamber 10 is brought to atmospheric pressure by the vacuum vent valve (not shown), the gate valve 52 between the sample exchange chamber 10 and the outside of the apparatus is opened, and the lift valve 14a is placed on the lift 14a. The placed sample W is taken out by the sample transport device 51 and stored in the wafer storage container 50 or another wafer storage container.
[0026]
In the present invention, as described above, the electrostatic chuck 2 is incorporated in the sample holder 1, the reference pin 4 and the drive pin 5 are provided for mechanical sample alignment and temporary sample position holding, The contact 6 is provided on the sample holder 1 side and the contact 24 is provided on the sample stage 21 side, and voltage application to the electrostatic chuck 2 is performed only when the sample holder 1 is mounted on the sample stage 21. In addition, a retractable auxiliary lift 8 is provided in order to easily and reliably attach and detach the sample W.
[0027]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the electrostatic chuck 2 has a donut shape and the lift 14a is passed through the center thereof. However, a plurality of lifts may be provided around the electrostatic chuck using an electrostatic chuck that is not a donut shape. . Although the contacts 6 and 24 have been described for applying a voltage to the electrostatic chuck 2, a plurality of contacts such as a terminal for measuring the absorption current of a charged particle beam and a terminal for applying a bias voltage to the sample are provided. Also good. Furthermore, if the reference surface 7 of the sample holder 1 is a taper type that opens downward and the positioning pins 12, 22 and the drive pins 13, 23, etc. are also open upward, the sample holder 1 can be fixed more reliably. Similarly, the drive pin 5 may be a taper type opened upward.
[0028]
Further, in the above-described embodiment, it has been described that the retractable auxiliary lift 8 moves in conjunction with the drive pin 5, but each may be driven independently.
[0029]
【The invention's effect】
As described above, in the present invention, voltage is applied to the electrostatic chuck 2 only in the sample chamber 20 by using the mechanical sample alignment mechanism as a temporary sample holding mechanism. Since no application is made in the sample exchange chamber 10 where dust can rise most, the adsorption of dust to the electrostatic chuck 2 is suppressed. This also eliminates the need for a mechanism for supplying voltage to the electrostatic chuck 2 when the sample holder 1 is moved from the sample exchange chamber 10 to the sample chamber 20.
[0030]
Further, by providing a retractable auxiliary lift 8, resistance and dust are prevented from being generated due to friction between the upper surface of the electrostatic chuck 2 and the lower surface of the sample W when the sample W is aligned. Desorption of sample W from By adopting this auxiliary lift 8, the spring 5d can be made sufficiently weak, and when the electrostatic chuck 2 is attracted, unnecessary force is not applied to the sample W, and the flattening of the sample W surface can be obtained smoothly. Further, when the sample W is lifted upward by the lift 14a when the sample W is detached, the peripheral portion of the sample W is separated from the reference pin 4 by the action of the auxiliary lift 8, so that the resistance and dust due to friction here are reduced. Occurrence can be prevented.
[0031]
Further, since the sample holder method is adopted, it is possible to easily cope with materials having different shapes, thicknesses, diameters, and the like of the sample, and the electrostatic chuck device can be easily cleaned and maintained.
[0032]
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a sample holder according to the present invention.
FIG. 2 is a sectional view showing an embodiment of a sample holder according to the present invention.
FIG. 3 is a view for explaining details of a sample holder according to the present invention.
FIG. 4 is a diagram for explaining the configuration and operation of a sample holder according to the present invention in a sample exchange chamber (preliminary exhaust chamber).
FIG. 5 is a diagram for explaining the configuration and operation of a sample holder according to the present invention in a sample chamber.
FIG. 6 is a diagram for explaining a relationship among a sample transport device, a sample exchange chamber (preliminary exhaust chamber), and a sample chamber.
[Explanation of symbols]
W ... Semiconductor wafer sample, 1 ... Sample holder, 2 ... Electrostatic chuck, 3 ... Lift through hole, 4 ... Reference pin, 5 ... Drive pin, 6 ... Contact, 7 ... Reference plane, 8 ... Auxiliary lift ) 10... Sample exchange chamber (preliminary exhaust chamber) 11... Sample holder platform 12. Positioning pin 13. Drive pin 14. Lift drive device 14 a Lift 15 Drive pin drive device 20 Sample Chamber, 21 ... Sample stage, 22 ... Positioning pin, 23 ... Drive pin, 24 ... Contact, 50 ... Wafer storage container, 51 ... Sample transfer device, 52 ... Division valve, 53 ... Division valve, 54 ... Charged particle beam optical system

Claims (3)

In a charged particle beam apparatus comprising a sample exchange chamber and a sample chamber for loading a sample holder for mounting a plate-like sample of a semiconductor wafer via the sample exchange chamber, the sample holder includes an electrostatic chuck device, Power receiving terminal means for the electrostatic chuck device, a reference part for defining the position of the sample, and a driving part for pressing and positioning the sample against the reference part and holding the position, wherein the specimen-exchange chamber is provided with means for driving the drive unit, the sample chamber is characterized by having means for supplying power to the electrostatic chuck device via the power receiving terminal means charged Particle beam device . 2. The charged particle according to claim 1, wherein the sample holder is provided with a tiltable sample lift means configured to place the sample in a direction in which the sample is driven by the driving unit and fall down. Beam device . 3. The charged particle beam apparatus according to claim 2, wherein the retractable sample lift means is interlocked with the drive unit.

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