JPH07302829A - Sample transfer table - Google Patents

Abstract

(57) [Summary] [Purpose] A sample moving table using a crossed roller guide, such as semiconductor manufacturing equipment and inspection equipment, eliminates the influence of the table weight and improves the accuracy and longevity of the sample moving table. To simplify the assembly and adjustment work. [Structure] As shown in FIG. 5, four intermediate weight cancellers 18 are provided on the intermediate table so that the rollers do not directly bear the own weight of the intermediate table. This weight canceller 1
Reference numeral 8 is a bearing, a leaf spring, and a load adjusting plate. When the adjusting screw 19 screwed into the intermediate table 9 pushes down the load adjusting plate, the leaf spring is bent around the shaft, and the force F for pushing the base table 8 by the bearing is generated. The structure is increasing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample moving table, and more particularly to a sample moving table such as a semiconductor manufacturing apparatus or an inspection apparatus which requires precise movement.

[0002]

2. Description of the Related Art Conventionally, a crossed roller guide is often used as a guide mechanism for a precision sample moving table because it is relatively inexpensive and easy to assemble. Usually, when using this crossed roller guide, the roller 15 supported by the cage 14 is sandwiched between the moving side rail 13 and the fixed side rail 12 as shown in FIGS. 12 by tightening the preload screw 16
Closely attach both rails to rail 5. By doing so, the table can be moved smoothly and accurately. The amount of preload is determined based on experience, etc., or is determined with reference to documents etc., and is controlled by the nominal diameter of the preload screw and the tightening torque.

[0003]

According to the above method,
The table of its own weight Mg is lifted by the preload and the roller 15 is pressed. Therefore roller 15
Is always under the weight of the table, which hinders proper preloading. Preload is not applied evenly to the entire rail. In addition, when assembling the table, if the table is lifted up and the heights of the fixed side rail 12 and the moving side rail 13 are made to coincide with each other and then the preload is not applied, the nonuniformity of the preload becomes more remarkable. Will end up. In particular, the heavier the table, the more severe the unevenness and the more difficult the assembly becomes.

In the case where the tables are stacked in three stages like the XY table (from the bottom, the base table, the intermediate table and the top table), when the intermediate table is incorporated into the base table, the weight applied to the rollers is the weight of the intermediate table. However, if the top table is installed on top of it, both the intermediate table's own weight and the top table's own weight will be applied to the preceding rollers, so it is necessary to make two adjustments in order to optimize the preload. It was

[0005]

According to the present invention, a table is
The above problems have been solved by providing a mechanism (elastic mechanism) for canceling the weight of the table itself and adding an adjusting mechanism capable of handling at least two stages of weight to the mechanism.

[0006]

With the above mechanism, the table is always lifted upward with a certain elastic force, and the height of the fixed side rail 12 and the height of the movable side rail 13 are exactly the same at the position where the own weight of the table and the elastic force are balanced. Has been adjusted. Therefore, the weight of the table is not applied to the roller 15 at all, only the preload is applied, the preload amount can be reduced, and the uniform preload can be applied to the entire rail.
When the tables are stacked in three stages (base table, intermediate table, and top table from the bottom) like the XY table, the intermediate table has a first load point supporting the intermediate table's own weight and the intermediate table's own weight. By installing an elastic mechanism that can handle two levels of weight, a second load point that supports the weight of the top table plus its own weight, and use the first load point when incorporating the intermediate table into the base table. After adjusting the preload and incorporating the top table on it, use the second load point. This eliminates the need for re-adjustment and facilitates assembly and adjustment work.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, 5, and 6.

FIG. 1 shows an overall configuration of an electron beam drawing apparatus adopting the present invention. The electron beam drawing apparatus is an apparatus that converges an electron beam emitted from the electron source 1 onto the sample 17 by the electron optical system 2 and forms a circuit pattern on the sample 17 at a desired position. The sample 17 is sample
The sample is transferred to the sample moving table 4 and fixed on the sample moving table 4 for X.
High-speed and accurate positioning is possible at any position in the Y-plane. A sample chamber 3 for accommodating the sample moving table 4 and a chamber for accommodating the electron source 1 are kept at a high vacuum by a vacuum pump 7.

FIG. 2 shows a detailed view of the sample moving table 4. A base table 8 is fixed to the sample chamber 3 kept in a high vacuum. An intermediate table 9 having a fixed side rail 12 attached to the base table 8 and a movable side rail 13 attached thereon is mounted via a roller 15. On the intermediate table 9, the fixed side rail 1 is attached so as to be orthogonal to the fixed side rail 12 attached to the base table 8.
2a is attached and has the same structure as the intermediate table 9,
A top table 10 is mounted. Intermediate table 9
And the top table 10 have drive systems 11a and 11 respectively.
Connected to b, the two tables move in directions orthogonal to each other.

FIG. 3 is a P view of FIG. 2, and FIG. 4 is a detailed view of an A portion of FIG. Since the guide mechanism between the base table 8 and the intermediate table 9 and the guide mechanism between the intermediate table 9 and the top table 10 have the same structure, only the former will be described. In the above configuration, the moving side rail 13 and the roller 15 are closely attached to the fixed side rail 12 and the roller 15,
A preload f is applied by the preload screw 16 to improve the guiding accuracy. Usually, the rollers 15 are composed of a plurality of rollers, and are held by the cage 14 in order to keep the intervals constant. Roller 15
Is the Nth and Nth from the end of the cage 14 as shown in FIG.
In the + 1st position, the axis of the roller 15 is offset by 90 °. That is, the axes of the rollers 15 are alternately inclined in opposite directions. Here, when the preload f is applied, the N-th roller pushes the moving-side rail 13 by the force of f ₁ and acts so as to lift the intermediate table 9. On the contrary, the N + 1th roller pushes the moving side rail 13 and pushes down the intermediate table 9 by the force of f ₂ . That is, f ₁ and f
_If the preload is not applied in consideration of the balance of ₂ , the table will be subjected to unreasonable force, which will adversely affect the stable running of the table and shorten the life of the roller or rail.

However, since a plurality of preload screws 16 (8 in this embodiment at a pitch of 50 mm) are arranged according to the length of the rail, these screws are uniformly tightened when the rail is assembled. Need to be crowded. In addition, since the intermediate table 9 naturally has its own weight Mg, it hinders the application of preload and causes the above-mentioned force imbalance when the table moves, which adversely affects the stable running of the table.

Therefore, in the present invention, as shown in FIGS. 5 and 6, four dead weight cancellers 18 are provided on the intermediate table,
The roller 15 was set so that the intermediate table would not be directly loaded by its own weight. This deadweight canceller 18 is a bearing 18
a, a leaf spring 18b, and a load adjusting plate 18c, and the load adjusting plate 1 is adjusted by an adjusting screw 19 screwed into the intermediate table 9.
When 8c is pushed down, the leaf spring 18b is bent around the shaft 18d, and the bearing 18a has a structure in which the force F pushing the base table 8 increases. That is, the table weight within a certain range can be dealt with by adjusting the screwing amount of the adjusting screw 19. A similar weight canceller 18 is attached to the top table 10.

According to the present embodiment, the weight canceller 18 attached to the intermediate table is adjusted so that the value of F is (the weight of the top table Mg ′ + the weight of the intermediate table Mg) /
If set to 4, all the preload amount will be used to stabilize the posture of the table, and the preload amount can be greatly reduced.
The life of rails and rollers can be extended. In addition, fluctuations in load on the rollers due to the weight of the table when the table is moved can be reduced, and accuracy can be improved. Further, when assembling the intermediate table, the weight canceller 18 is adjusted to set the value of F to (the own-weight Mg of the intermediate table) / 4, so that the weight of the table does not hinder the assembling work. Adjustment of preload becomes easy. Next, after incorporating the top table, if the value of F is set to (the weight of the top table Mg ′ + the weight of the intermediate table Mg) / 4, the sample moving table having the above-described effect can be assembled.

[0014]

According to the present invention, by canceling the weight of the table itself, an appropriate preload is applied to the crossed roller guide, which improves the accuracy of the sample moving table, prolongs its life, and simplifies the assembly adjustment work. It will be possible.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an electron beam drawing apparatus.

FIG. 2 is a detailed view of a sample moving table.

FIG. 3 is a P view of FIG.

FIG. 4 is a detailed view of part A of FIG.

FIG. 5 is a detailed view of the present invention.

FIG. 6 is a diagram showing a self-weight canceller.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electron source, 2 ... Electron optical system, 3 ... Sample chamber, 4 ... Sample moving table, 5 ... Sample exchanging device, 6 ... Vibration isolation table, 7 ... Vacuum pump, 8 ... Base table, 9 ... Intermediate table, 10 ... top table, 11a, 11b ... drive system, 12 ... fixed side rail, 13 ... moving side rail, 14 ... cage, 15 ... roller, 16 ... preload screw, 17 ... sample, 18 ... dead weight canceller, 18a ... bearing, 18b … Leaf springs, 18
c ... load adjusting plate, 18d ... shaft, 19 ... adjusting screw.

Claims (2)

[Claims] 1. A base table for fixing, an intermediate table movable on the base table in one direction, a top table movable on the intermediate table in one direction and holding a sample, and the base. A crossed roller guide as a sliding mechanism between the table and the intermediate table,
A crossed roller guide as a sliding mechanism between the intermediate table and the top table, a drive mechanism for driving the tables, and a sample moving table including a control system for controlling the drive mechanisms, wherein the intermediate table and the top table are provided. A sample moving table characterized in that a mechanism for canceling the respective self-weights is provided in and, and the structure is such that an appropriate preload is applied to the crossed roller guide. 2. The sample moving table according to claim 1, wherein the mechanism for canceling the self-weight of the intermediate table is capable of setting the load in at least two stages.