JPH0130300B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cassette holding device for an electron beam apparatus that can position and stably hold a cassette fixedly holding a sample to be subjected to electron beam irradiation on a sample stage with high precision. .

When micromachining samples such as semiconductor wafers and masks to submicron order using electron beams, it is necessary to place the cassette holding the sample fixedly on the sample stage of the electron beam device with high precision and reliably. need to be retained. Figures 1a to 1c show an example of such a conventional cassette holding device.
2 is the cassette that holds the sample fixedly, and 2 is the cassette 1.
The sample stage on which the sample is placed and fixed is shown. A position regulating body (stopper) 3 is provided at the end of the sample stage 2 to abut against the end of the insertion cassette to regulate the insertion position of the cassette 1, and on the side of the sample stage 2, the above-mentioned Along the insertion direction of the cassette 1, a cassette holding mechanism 7 consisting of a steel ball 4 as shown in FIG. It is being The holding mechanism 7 has the end of the holder 6 fixed onto the sample stage 2 with a screw 8, and a steel ball 4 pressed downward by a spring body 5 is attached to the side protrusion of the holder 6. We are prepared. However, the cassette 1
is inserted with its side part between the sample stage 2 and the steel ball 4, and is loaded to the position where it contacts the position regulating body 3 against the pressing force applied by the steel ball 4. Therefore, it is fixedly held on the sample stage 2.

However, in the case of a cassette holding device having such a conventional structure, the cassette 1 contacts the steel balls 4 with its sides and is loaded by pushing up the steel balls 4, so that the pressing force applied by the steel balls 4 is reduced. This causes significant wear between the cassette 1 and the sample stage 2. The abrasion powder generated by this abrasion causes problems such as changing the coefficient of friction and changing the cassette holding force, and becoming a charging source for electron beams. In addition, the cassette may become misaligned due to a decline in the cassette holding function.
Alternatively, as shown in FIG. 1c, a lateral movement force F is generated due to shape change due to wear and convexity. For this reason, the positioning accuracy gradually decreases during long-term use, and at the same time, stable and reliable holding performance is lost.

The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to maintain high positional accuracy on a sample stage to ensure stability of a cassette holding a sample to be subjected to electron beam irradiation. It is an object of the present invention to provide a simple and highly practical cassette holding device for an electron beam device that can hold a cassette.

First, an overview of the present invention will be explained. The present invention has a structure in which the cassette holding mechanism is configured to press the cassette toward the sample stand and fix it to the sample stand, and to release the pressing action when feeding and removing the cassette. The cassette guide mechanism is provided with a cassette guide mechanism consisting of rolling elements that come into contact with the lower surface (guide surface) of the cassette during loading and unloading.
Therefore, the cassette can be smoothly fed and taken out, and the cassette whose position is precisely regulated can be reliably and stably held with high positional accuracy.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figures 2a to 2c show the first embodiment, and a
1 is a plan configuration diagram, and b and c are side configuration diagrams showing the effect. In the figure, reference numeral 11 denotes a sample stage, which is, for example, an X-Y table provided in an exposure chamber of an electron beam apparatus, and a cassette 12 is placed on this sample stage 11 and held fixed thereon. As explained earlier, this cassette 12 is a rectangular plate in which a sample such as a semiconductor wafer or a mask to be subjected to electron beam irradiation, for example, exposure, is pressed and held by a predetermined adhesive or spring force. It has a shape with a flange protruding from the longitudinal side surface. The cassette 12 is supported by the tip of a moving rod to be described later, and is transported onto and taken out from the sample table 11 from the longitudinal direction.

A position regulating body (stopper) 13 is arranged and fixed in a straight line at the longitudinal end of the sample stage 11. These position regulating bodies 13 are arranged on the sample stage 11.
It comes into contact with the longitudinal end face of the cassette 12 loaded thereon to regulate the position of the cassette 12. Furthermore, base blocks 14 are provided protruding from both sides of the sample stage 11 in the lateral direction. An end portion of a swing arm 15 is connected to these base blocks 14 by a pin 14a, and is supported so as to be freely rotatable in the vertical direction. Further, the other end of a spring body 17 whose one end is fixed to a screw 16 screwed into a base body 11a protruding in the side direction of the sample stage 11 is locked to the other end of the arm 15. 1
The arm 15 is urged downward by the compressive force of 7. A presser plate 18 is provided at the intermediate portion of the arm 15 and is rotatably supported by a pin 15a. This holding plate 18 is made of a plate body long in the longitudinal direction of the sample stage 11, and receives the downward biasing force of the arm 15 to generate a downward pressing force. Also, arm 15
A plate body 19a is provided to protrude downward, and this plate body 1
The roller 19c is connected to the lower end of the roller 9a via the pin 19b.
(rolling elements) are connected. When loading and unloading the cassette 12, the cassette 12 is guided by the rollers 19c without contacting the sample stage 11 and the holding plate 18, as shown in FIG. 3a.
Furthermore, when the cassette 12 is fixed, the cassette 12 sinks by an amount h in the figure, and the side flanges of the cassette 12 are pressed against the presser plate 18 and the sample stage 1, as shown in FIG. 3b.
It has become something that is sandwiched between 1 and 1.

On the other hand, the other end of the arm 15, that is, the spring 17
An abutment piece 20 is provided inwardly at the end where the two are connected. This contact piece 20 is attached to a fixed block 21
2b, which is in contact with the leg body 23 which is urged in the direction A in the figure by the drive shaft 22 which is rotatably supported in FIG.
It can be lifted as shown in the figure. That is, the leg 23 is normally pushed down by the drive shaft 22 at its end, as shown in FIG. 2c, and separated from the abutment piece 20. Also, when the cassette 12 or the moving rod for feeding and unloading the cassette 12 is loaded, that is, when the cassette 1
2, the leg 23 is rotated by the drive shaft 22 in the direction A as shown in FIG. 2b. Due to this rotation of the leg 23, the tip of the leg 23 abuts the abutment piece 20 from below and lifts the abutment piece 20. Therefore, the arm 15, which has an integral structure with the abutment piece 20, is connected to the spring body 17.
As a result, the holding plate 18 is moved upward and separated from the flange surface of the cassette 12. Note that a pneumatic cylinder or the like is used to drive the drive rod 22 or the leg body 23.

According to this apparatus configured in this way, the sample stage 1
When loading and unloading the cassette 12 onto and from the cassette 1, the lifting of the arm 15 by the legs 23 releases the holding and fixing function of the cassette 12 by the presser plate 18, so that the presser plate 18 and the cassette 12 do not come into contact with each other. At the same time, the cassette 12 is lifted upward by the roller 19c and placed on the sample stage 11.
Both will be in a non-contact state. Therefore, the cassette 12 can be freely taken in and out of the sample stage 11. When loading the cassette 12 onto the sample stage 11, the cassette 12 is fed onto the sample stage 11 in the above-mentioned free state, and the cassette 12 is loaded onto the sample stage 11.
After the end of the arm 15 is brought into contact with the position regulating body 13 to regulate its position, if the locking force of the leg body 23 of the contact piece 20 is released, the arm 15 receives the spring force of the spring body 17 and moves downward. is rotated. The presser plate 18 moves downward in response to the downward rotational force of the arm 15 and applies a pressing force to the sample stage 1.
The cassette 12 inserted onto the sample stage 11 is firmly fixed and held on the sample stage 11 with its position regulated. Moreover, the holding force by this presser plate 18 is
It is determined by the lever ratio between the spring force of the spring body 17 and the rotational fulcrum of the arm 15 (positions of the pins 14a and 15a), and can be adjusted by rotating the screw 16 back and forth. Furthermore, when taking out the cassette 12, by rotating the leg 23, the holding plate 18 is lifted by the rotation of the arm 15, and its pressing and fixing holding force is released, so that the cassette 12 can be taken out easily. can.

Therefore, according to this device, since there is no friction between the cassette and the steel balls unlike in the conventional mechanism, it is possible to improve the positioning accuracy. Moreover, there is no need to slide the cassette 12 on the sample stage 11 as in the conventional case.
Since it is rolled by the rollers 19c, there is no wear on the highly precisely manufactured sample stage 11 and cassette 12. Therefore, the cassette 12 can be held reliably and stably over time. In addition, since the cassette 12 is securely held by the vertical pressing force, there is no risk of positional displacement due to the movement of the sample stage 11, and no positional displacement force F due to the aforementioned component force is generated. Therefore, it has excellent retention characteristics. Furthermore, there is no need to consider charging power sources due to wear particles. Furthermore, cassette 1
2 can be carried out very smoothly, and the structure itself is simple and practical.

4 and 5 respectively show a second embodiment of the present invention, with FIG. 4 being a plan view and FIG. 5 being an enlarged side view with a portion cut away. In addition, Figure 2 a~
The same parts as c are denoted by the same reference numerals, and detailed explanation thereof will be omitted. A spring body 17 is connected to the swinging arm 15, which moves the holding plate 18 in the vertical direction with respect to the upper surface of the sample stage 11, as in the previous embodiment, and is always biased to rotate in the B direction. Also,
A brittle plate 31 is spanned between the ends of both arms 15, and as the brittle plate 31 rotates, both arms 15 simultaneously rotate. The drive mechanism 32 for the brittle plate 31 has a pivot shaft 34 rotatably supported in a bearing sleeve 33. The shaft 34 is provided with a pair of arms 35 that protrude through the bearing cylinder 33 and whose tips face the lower side of the brittle plate 31. Also, shaft 3
A pinion 36 is fixed coaxially to one end of the pinion 4, and a rack 37 is meshed with the pinion 36 so as to be movable in the vertical direction. This easy 3
7 is the shaft 3 of the plunger 38 as shown in FIG.
8a, and the rack 37 is thus selectively moved up and down by the plunger 38.

Four guide rollers 39a to 39d are provided on the sides of the upper surface of the sample stage 11 so as to be rotatable about a vertical axis. These guide rollers roll against the sides of the cassette during loading and unloading movements to prevent excessive shifting of the cassette in the X direction. Three rollers 39a, 39c, 39
d is provided at a distance equal to or more than the thickness of the flange portion of the cassette from the top surface of the sample stage 11, and is in rolling contact with the side surface of the cassette body, while the roller 39b is provided almost near the top surface of the sample stage 11 to prevent the cassette from collapsing. Makes rolling contact with the side of the flange.

A detection mechanism 40 for detecting the position of the cassette 12 where the cassette 12 comes into contact with the position regulating body 13 is provided in the rear direction of the upper surface of the sample stage 11. This detection mechanism 40, for example,
It can be configured by a combination of a photodiode that allows light to enter a reflecting section formed at a predetermined position on the top surface of No. 2, and a photocell that receives light from the reflecting section and converts it into an electrical signal. A signal from this detection mechanism 40 is sent to a controller 41 to control the plunger 38. Although not shown in FIGS. 4 and 5, a cassette guide mechanism consisting of a plate 19a, pins 19b and rollers 19c is provided below the presser plate 18, as in the previous embodiment.

In the cassette holding device configured as described above, when the cassette 12 is inserted, the plunger 38 is lowered by a manual switch or a switch that detects the movement of the cassette 12, and the two swing arms 15 is rotated in the opposite direction of arrow B against the biasing force of spring body 17. As a result, the presser plate 18 is raised to a position where the cassette can be inserted. In this state, the cassette 12 is slid forward with the flange portion positioned below the presser plate 18, and its front end is brought into contact with the position regulating body 13. At this time, cassette 12
is in a non-contact state with the sample stage 11 and the presser plate 18 and is guided by rollers 19c. Then, the detection mechanism 40 detects that the cassette 12 is held at a predetermined position, and the plunger 38 is deenergized via the controller 41. As a result, the swing arm 15 is rotated by the spring 17 in the direction of the arrow, and the presser plate 18 is lowered to press the flange portion of the cassette 12 onto the sample stage 11, thereby holding the cassette 12 at the predetermined position. When taking out the cassette 12, the plunger 38 is driven again and the holding plate 18 is separated from the upper surface of the flange portion of the cassette via the swing arm 15.

Thus, according to the present apparatus, when the cassette 12 is transferred to and taken out from the sample stage 11, the function of holding the cassette 12 by the presser plate 18 is lifted by lifting the arm 15, as in the first embodiment described above. When the cassette 12 is released, the cassette 12 is lifted by the roller 19c and kept out of contact with the sample stage 11 and the presser plate 18.
Therefore, the same effects as the first embodiment described above are achieved.

6a and 6b show a third embodiment of the present invention, in which a is a sectional view of the fixing mechanism and b is a side view of the fixing mechanism. In this mechanism, a base member 51 fixed on a sample stage 11 is provided with a pressing member 53 that is biased upward by a spring 52. The pressing member 53 rotatably supports a roller 54 at its upper end, and the roller 54 is opposed to a roller 55 rotatably supported on the upper part of the base body 51.
A wedge piece 56, which is a fixed mechanism control body and has a predetermined taper and has a vertical spring force greater than that of the spring body 52 in the internal cavity, is inserted between these rollers 54 and 55. The roller 54 is pressed downward by the piece 56 and the presser member 53
is configured to be pushed downward against the spring 52. The flange of the cassette 12 is inserted between the lower end of the holding member 53 pressed by the base body 51 and the sample stage 11, and is held fixed. Although not shown in Figures 6a and b, sample stage 1
A recess is formed in the upper surface of the sample stage 11, and a cassette guide mechanism consisting of a roller or the like that is pushed up above the upper surface of the sample stage 11 by a spring or the like is provided in this recess. The rollers and the like are pushed down from the upper surface of the sample stage 11 by pressing the cassette 12 downward.

Therefore, when loading and unloading the cassette 12, if the wedge piece 56 is pulled out from between the rollers 54 and 55, the holding member 53 is pulled upward, and the cassette 12 is lifted from the top surface of the sample stage 11 by the guide mechanism. The wedge piece 5 becomes free.
When the cassette 6 is pushed between the rollers 54 and 55, the holding member 53 is pressed downward, so that the cassette 12 is held and fixed stably and securely. Therefore, the same effects as in the previous embodiment can be achieved.

FIG. 7 is a block diagram of main parts showing a fourth embodiment of the present invention. In this embodiment, a steel ball 62 and a spring 63 for pressing the steel ball are provided in the inner cylindrical portion of a base body 61 provided on a sample stage 11. steel ball 6
The amount of downward protrusion of the cassette 2 is regulated by the flange 64, and is set to have a predetermined gap with the flange of the cassette 12 placed on the sample stage 11. On the other hand, the cassette 12 is provided with a wedge body 65 that is slidable laterally, and the abutting portion 66 is normally set at a position not facing the steel balls 62. The contact portion 66 is moved to a position facing the steel ball 62 by sliding the wedge body 65, and the steel ball 62 is lifted by contact with the steel ball 62. Therefore, the lifting of the steel ball 62 is performed against the spring 63, so that the contact portion 66 receives a downward pressing force from the spring 63 via the steel ball 62, and thereby The flange of the cassette 12 is pressed to hold it fixed. Also in this case, a guide mechanism (not shown) is provided on the sample stage 11 as in the third embodiment. Therefore, by sliding the wedge body 65, it is possible to smoothly set the cassette 12 on the sample stage 11, and then securely fix the cassette 12 via the steel balls 62 and the contact portion 66. Therefore, the same effects as those of the above-mentioned embodiments are achieved.

It should be noted that the present invention is not limited to the above-described embodiments. In the embodiment, the fixing of the cassette is mechanically controlled, but it goes without saying that it may be electrically controlled using a plunger mechanism. Alternatively, a sensor for detecting the presence (contact) of the cassette 12 may be provided on the position regulating body, and the cassette holding mechanism may be driven in response to the output of this sensor. Further, the holding plate of the cassette holding mechanism may be configured to be controlled by an air cylinder or the like, and the number of holding plates (members) provided on the sample stage 11, their positions, etc. can be set as appropriate according to the specifications. do it. Furthermore, the guide mechanism does not need to be integrated with the presser plate as shown in Fig. 2;
It may be fixed so as to be pushed up from above the sample stage with a spring or the like and pushed down when the cassette is lowered, or it may be moved up and down independently using another driving method. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of drawings]

Figures 1 a to b are diagrams showing an example of a conventional device;
Figures a to c are schematic configuration diagrams showing the first embodiment of the present invention, Figures 3a and b are major configuration diagrams for explaining the operation of the above embodiment, and Figures 4 and 5 are respectively Schematic configuration diagram showing the second embodiment, Figures 6a and b
is a main part configuration diagram showing the third embodiment, and FIG. 7 is a diagram showing the fourth embodiment.
FIG. 2 is a main part configuration diagram showing an embodiment of the present invention. 11...sample stand, 12...cassette, 13...
Position regulating body, 14...Base block, 15...
Swinging arm, 17... Spring body, 18... Pressing plate,
19a... Plate, 19b... Pin, 19c... Roller, 20... Contact piece, 21... Fixed block,
22... Drive shaft, 23... Leg body, 31... Bridge plate, 32... Drive mechanism, 33... Bearing tube, 3
4...Shaft, 35...Arm, 36...Pinion, 37...Rack, 38...Plunger, 5
1... Base body, 52... Spring, 53... Pressing member, 54, 55... Roller, 56... Wedge piece, 61
... Base body, 62 ... Steel ball, 63 ... Spring, 6
5... Cuneiform body, 66... Contact portion.

Claims (1)

[Scope of Claims] 1. A sample stage on which a cassette holding a sample to be subjected to electron beam exposure is mounted, and a sample stage provided on the cassette mounting surface side of the sample stage and abutting against the end of the cassette. a position regulating body that regulates the stop position of the cassette; and a position regulating body that presses the position-regulated cassette against the sample stand and fixes it to the sample stand, and releases the pressing action when feeding and removing the cassette. a cassette holding mechanism, and a cassette guide, which is movably provided on the cassette holding mechanism or the sample stage, and includes rolling elements that guide and support the cassette by contacting the guide surface of the cassette when the cassette is fed and taken out. A cassette holding device for an electron beam device, characterized by comprising a mechanism. 2. The cassette holding mechanism includes a presser plate that is movable in the vertical direction of the sample stage and that presses both sides of the upper surface of the cassette to hold the cassette;
a rocking device that is rotatably provided on the sample stage about a first horizontal axis and supports the presser plate so as to be rotatable about a second horizontal axis that is parallel to the first horizontal axis; an elastic body that pivots and urges the swinging arm in one direction to press the presser plate against both sides of the upper surface of the cassette; and an elastic body that pivots the swinging arm in the other direction against the pressure of the elastic body 2. The cassette holding device for an electron beam apparatus according to claim 1, further comprising a drive mechanism that biases the holding plate and releases the pressing action of the holding plate. 3. The swinging arm is rotatably supported on the sample stage at one end thereof, and the holding plate is rotatably supported in the middle of the swinging arm. A cassette holding device for an electron beam apparatus according to scope 2. 4. The cassette holding device for an electron beam apparatus according to claim 2, wherein the drive mechanism comprises an electromagnetic plunger. 5. The cassette holding device for an electron beam apparatus according to claim 2, wherein the drive mechanism is comprised of an air cylinder. 6. The electron beam apparatus according to claim 2, characterized in that the cassette guide mechanism is attached to the holding plate and moves up and down in response to movement of the holding plate. Cassette holding device.