JPH0766067B2 - Ultra high vacuum table - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high vacuum table used for a thin-film processing apparatus, an inspection apparatus, etc. for processing and inspecting thin films such as semiconductors in an ultra-high vacuum environment. is there.

Conventional technology When performing thin film processing or inspection of semiconductors in an ultra-high vacuum environment, the table used for these thin film processing and inspection equipment must be operated reliably, and the reaction with impurities gas and components on the thin film processing surface In order to prevent the generation of harmful substances or to improve the resolution for analyzing the state of the inspection surface layer interface, the thermal distortion of each member in the table used for these thin film processing and inspection devices is prevented, and the table itself What can be used in an ultra-high vacuum environment in which the generation of emitted gas from the gas is small is needed. The outline of the conventional ultra-high vacuum table will be described below.

A first moving table (Y-axis moving table) and a second moving table (X-axis moving table) are respectively supported on the base by linear guides so as to be movable in orthogonal directions. The first and second moving tables are moved by power transmission means including first and second stepping motors and feed screws and nuts, respectively. Each stepping motor is installed outside a vacuum chamber (not shown), and the output shaft of this stepping motor is connected to the base end of the feed screw by a bellows coupling. The work table has columnar slides protruding from the four corners of the lower surface, and these slides are slidably mounted on the base while sandwiching the first and second moving tables, respectively.

Next, the operation of the above conventional example will be described.

By rotating the feed screw by driving the first stepping motor, it is possible to move the nut, the first moving table, and the like screwed onto the feed screw in the Y-axis direction along the linear guide. The slide table and the work table can be moved in the Y-axis direction by pressing the slide table. On the other hand, by rotating the feed screw by driving the second stepping motor, it is possible to move the nut, the second moving table, etc. screwed onto the feed screw in the X-axis direction along the linear guide. Along with this, the slide table can be pushed to move the slide table and the work table in the X-axis direction.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In order to create a vacuum in the vacuum chamber, it is necessary to heat the vacuum chamber to degas (bak) it. At this time, thermal distortion occurs in each member, but if a linear guide is used as the guide means of the moving table as in the above-mentioned conventional example, the linear guide base of this linear guide is fixed to the base by bolts, and the moving portion is moved to the first position. Alternatively, since they are fixed to the second moving table with bolts, they are in a bite state and the feed screw cannot be rotated.

Therefore, it could only be used in an atmosphere of 10 ^-7 Torr level, and could not be used in an ultra-high vacuum environment. In order to avoid such an influence of thermal strain, a large clearance may be provided in advance in the mechanical contact portion, but this is very inaccurate. Further, in the above conventional example,
All of its parts are made of stainless steel, the linear guide requires oil removal treatment and the use of silicone grease, and the bolts are not surface treated. Moreover, in order to slide the slide smoothly on the base, MOS ₂ (molybdenum disulfide) is used.
Etc. are applied. Therefore, these oils and the like deteriorate the degree of vacuum and the quality of the vacuum in the vacuum chamber, and cannot be said to be a preferable vacuum environment. In order to reduce the deterioration of the vacuum environment, a stepping motor is installed outside the vacuum chamber, and its output shaft and feed screw are connected by a bellows coupling, so when driving the stepping motor, a bellows coupling is used. The rotation angle of the feed screw fluctuated due to the fluctuating load, and the feed accuracy was further deteriorated.

The present invention is to solve the problems of the conventional techniques as described above, even if a thermal strain occurs in each part, it is possible to freely absorb this thermal strain without fear of damage, and moreover, the moving table can be moved horizontally. Direction, vertical direction, inverted horizontal direction, etc. can be set and held in any posture, and therefore, the moving table can be smoothly moved in any posture in the ultra-high vacuum environment in the same manner as in the atmosphere. It is an object of the present invention to provide an ultra-high vacuum table that can be operated with high precision and that can be easily assembled and adjusted.

Means for Solving the Problems A technical means of the present invention for solving the above problems is to provide a pair of first and second cylindrical guide shafts arranged in parallel, and these first and second guide shafts. Grooves that are rotatably engaged with the movable table that moves along the axis and the first and second guide shafts, respectively, and that expand symmetrically and conically on both sides from the central portion along the axial direction. First and second guide rollers each having a groove for moving the moving table along the first and second guide shafts.
Support means for rotatably supporting the first guide roller at a fixed position and the second guide roller by means of a spring for the second guide roller.
Means for holding the first and second guide rollers under pressure so that the first and second guide rollers cooperate with each other so as to absorb thermal strain, and for moving the moving table. And a power transmission means linked to the drive device and the moving table using a spring so as to absorb thermal strain.

Action The present invention has the following actions by the above technical means.

The moving table can be moved by the driving device via the power transmission means by the guide of the first and second guide shafts and the first and second guide rollers. Then, the second guide roller is supported on the moving table by using a spring so as to absorb thermal strain, and the first and second guide rollers are made to cooperate with each other to be held by the first and second guide shafts. In this way, since the driving position and the moving table are linked so as to absorb the thermal strain by the power transmission means using the spring, when the vacuum chamber is heated and the gas is degassed, the above-mentioned members are subjected to the thermal strain ( Even if thermal expansion occurs, this can be absorbed.
In particular, since the second guide roller side is biased by the spring instead of the second guide shaft side as described above, when the reference side first guide shaft is mounted with sufficient accuracy, The local distortion of the guide shaft can be sufficiently covered by the suspension-like movement of the spring of the second guide roller.

Therefore, it is possible to operate in an ultrahigh vacuum environment of the order of 10 ^-11 Torr, and after cooling, each member can be automatically returned to the state before heating. Also, the first and second
Of the guide roller is formed with a groove so as to be engaged with the first and second columnar guide shafts, and as described above, the second guide roller can absorb the thermal strain on the moving table. Since it is supported by a spring and the first and second guide rollers are made to cooperate with each other to be held by the first and second guide shafts, the moving table is supported in the horizontal direction, the vertical direction,
Alternatively, the first and second guide rollers and the first and second guide shafts can be reliably held in the engaged state even if they are set in any posture such as the inverted horizontal direction.

Examples Hereinafter, examples of the present invention will be described with reference to the drawings.

1 to 5 show an ultrahigh vacuum table according to an embodiment of the present invention. FIG. 1 is a plan view, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 1 is a sectional view taken along the line III-III in FIG. 1, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, and FIG.
FIG. 5 is a sectional view taken along the line VV in the figure.

As shown in FIGS. 1 to 3, support blocks 2 are attached to the four corners of the support base 1 by bolts 3, and holes 4 are formed so as to face the support blocks 2 on the longitudinal edge side of the support base 1. . A pair of first and second cylindrical guide shafts 5a and 5b are inserted into the holes 4 facing each other, and a screw 7 is screwed into a screw hole 6 formed in each support block 2 at a right angle to the hole 4. , Each screw 7 has first and second guide shafts 5a and 5b
And the first and second guide shafts 5a and 5b are fixed in parallel with each other. Bolts 10 are inserted into the mounting holes 9 formed at a plurality of positions on both sides of the moving table 8 in a loosely fitted state, and the tip ends of the bolts 10 are mounted on the lower sides of the moving table 8 on both sides of the supporting blocks 11a and 11b. It is screwed into the screw hole 12. The head of the bolt 10 on the side of the support block 11a is embedded in the shallow large-diameter portion of the mounting hole 9, and the lower surface is tightened so as to be pressed against the bottom surface of the large-diameter portion. As a result, the support block 11a is fixed to the moving table 8. The head of the bolt 10 on the side of the support block 11b is embedded in the deep large-diameter portion of the mounting hole 9, and the washer 13 and the disc spring 14 are provided on the lower surface and the bottom of the large-diameter portion on the outer circumference of the screw shaft. .
As a result, the support block 11b uses the clearance between the small-diameter portion of the mounting hole 9 and the screw shaft of the bolt 10 to resist the pressure contact force of the disc spring 14 and to be closer to or closer to the support block 11a. Be moved to the side. Each support block
Support holes 15 are formed in two portions of the support holes 11a and 11b along the first and second guide shafts 5a and 5b, and a bearing 16 is mounted in each support hole 15. Each bearing 16 on the side of the first guide shaft 5a has a shaft 18 protruding from the first guide roller 17a.
The nut 20 is screwed into the threaded portion of the shaft 18 in the hole 19 formed in the moving table 8. The nut 20 is tightened with the washer 21 between the inner race of the bearing 16 and the inner race. , Rotatably supported. Second guide shaft 5b
A shaft 18 protruding from the second guide roller 17b is also rotatably supported by a nut 20 and a washer 21 on each side bearing 16 as well. Each of the guide rollers 17a, 17b is formed in a drum shape (opposing conical shape) with a groove that opens symmetrically on both sides from the central portion along the axial direction and has a conical shape. Groove like this
The groove 22 is formed so as to become gradually narrower from the open side to the inner side, and the wall surface of this groove 22 is the first and second guide shafts 5a, 5b.
Is rotatably engaged with the inside thereof. Therefore, the first and second guide shafts 5a and 5b and the first and second guide rollers 17a and 17b can be easily assembled and adjusted. A support block 23 is attached to the end surface of the moving table 8 on the side of the support block 11b with bolts 24, and the support block 23 is provided with each second block.
A hole 25 is formed corresponding to the position of the guide roller 17b. An adjustment pin 26 is inserted through each hole 25, and a threaded portion at the tip of each adjustment pin 26 is screwed into the support block 11b.
A compression spring 27 and a washer 28 from the base end of each adjustment pin 26 in order.
Is fitted, and nuts 29 are attached to the threads on the base end of each adjustment pin 26.
Are screwed together, and the compression spring 27 is attached to the support block 23 and the washer 28.
Is interposed between and in a compressed state. Therefore, due to the anti-elasticity of the compression spring 27, the adjustment pin 26 and the support block 11b are
Also, the second guide roller 17b is pressed in the direction in which it is separated from the support block 11a and the first guide roller 17a, and the second guide roller 17b is pressed by the second guide shaft 5b. As a result, the first and second guide shafts 5a and 5b can be held so that the first and second guide rollers 17a and 17b can cooperate with each other to absorb thermal strain.

The moving table 8 is a stepping motor 30 which is a driving device.
And a ball screw which is a power transmission means. The stepping motor 30 is mounted on the support 1 by a bolt 31 on one side between the first and second guide shafts 5a and 5b. A support block 32 is attached by a bolt 33 to the other side between the first and second guide shafts 5a and 5b on the support base 1,
In particular, as is apparent from FIG. 4, the sleeve 35 is inserted into the hole 34 of the support block 32, and the flange 36 integrally attached to the sleeve 35 is fixed to the support block 32 by the bolt 37. A tip end of a screw shaft 38 of a feed screw which is an output shaft of the stepping motor 30 is rotatably supported by a sleeve 35 via a bearing 39. A support block 40 is fixed to the center of the lower surface of the moving table 8 with bolts 41. In particular, as is clear from FIG. 5, the support block 40
The nuts 43 and 44 of the ball screw are loosely inserted into the holes 42 of the, and the collar 44 of the support block 40 and the nut 44 is inserted into the nut 44.
An annular plate 47 is loosely fitted between it and an annular plate 46 provided inside 45. A concave groove 48 having a V-shaped cross section is formed on the surface of the annular plate 47 on the side of the support block 40 in a direction orthogonal to the axial center.
A recessed groove 49 having a V-shaped cross section is formed on the surface opposite to 47 in a direction orthogonal to the recessed groove 48, and the annular plate 46 has a V-shaped recessed groove 50 corresponding to the recessed groove 49. Are formed. Plural bolts 51 are inserted in the flange-shaped portion 45 of the nut 44, the annular plate 46, the annular plate 47, and the support block 40 in a loosely fitted state, and the nut 52 is screwed to the tip end of each bolt 51. A compression spring is provided between the nut 52 and the support block 40 on the outer circumference of each bolt 51.
53 are interposed, and a plurality of balls 54 are interposed between the support block 40 and the recessed groove 48 of the annular plate 47.
A ball 55 is interposed between 49 and the recessed groove 50 of the annular plate 46,
Due to the elasticity of the compression spring 53, the annular plate 46 inside the flange portion 45 of the nut 44 is pressed against the annular plate 47 via the plurality of balls 55, and the annular plate 47 supports the supporting block via the plurality of balls 54.
Pressured to 40. The screw shaft 38 is engaged with the nuts 43 and 44 via balls (not shown). Therefore, by rotating the screw shaft 38 by driving the stepping motor 30, the movable table 8 or the like is moved via the nuts 43 and 44 to the first and second guide shafts 5a and 5b and the first and second guide rollers 17a. It can be moved by following the guidance in 17b. Then, the nuts 43 and 44 are attached to the compression springs 53,
By supporting the support block 40 via the balls 54, 55, etc., it is possible to absorb thermal strain of each member due to heating in each direction, and the bending of the screw shaft 38 affects the moving table 8. Can be prevented. Support stand 1
A support block 56 is fixed to the upper part by bolts 57 at two edge portions along one of the first guide shafts 5a.
A proximity switch 58 is supported on the top. On the other hand, on the end surface of the moving table 8 on the first guide shaft 5a side, a support block 59 is fixed between the proximity switches 58, 58 with a bolt 60, and the lower surface of the support block 59 has a proximity switch.
A magnet 61 that operates 58 is fixed by a bolt 62.

In each of the above-mentioned members, bolts, nuts, washers, springs, balls, etc. for fixing the parts are subjected to pickling, heat degassing, or other strength members, such as stainless steel materials whose surface is coated with Ag. Material is aluminum alloy
It is processed in Ar + O ₂ to form a dense and hard oxide film on the surface and uses a material with reduced impurities. Therefore, it is possible to extremely reduce the generation of released gas from each member during heating. Also, the above stepping motor
A cable (not shown) used for the stator of 30 has an insulating coating on the outer periphery of the core wire, and the outer periphery of the insulating coating is covered with a tube made of stainless steel so that the generation of released gas during heating can be extremely reduced. As a result, the stepping motor 30 can be installed in a vacuum chamber (not shown).

The operation of the above configuration will be described below.

Drive the stepper motor 30 and screw shaft 38
This screw shaft 38
The nuts 43 and 44, the moving table 8 and the like, which are engaged with each other via balls, are moved in either direction by the guides of the first and second guide shafts 5a and 5b and the first and second guide rollers 17a and 17b. Can be made. At this time,
The limit moving position of the moving table 8 can be detected by the magnet 61 operating any one of the proximity switches 58. Then, when the vacuum tank is heated to degas the inside of the vacuum tank to create an ultra-high vacuum environment, the thermal distortion of the first and second guide shafts 5a and 5b, etc. is applied to the first guide roller 17a as described above.
The compression spring 27 can absorb the side, and the thermal strain of the feed screw 38 and the like can be absorbed by the interposition of the compression spring 53 and the balls 54, 55. Therefore, in an ultrahigh vacuum environment of the order of 10 ^-11 Torr, the moving table can be operated as smoothly as in the atmosphere and with high accuracy. Also,
Since each member is made of a material that emits very little gas during heating as described above, the inside of the vacuum chamber can be maintained in a preferable environment. Further, since the stepping motor 30 for moving the moving table 8 can be installed in the vacuum chamber as described above, the fluctuation of the power transmission mechanism as in the prior art is eliminated and the feeding accuracy is further improved. be able to. As a result of the test, it could be operated in the atmosphere of 10 ^-11 Torrk ultra-high vacuum in the same manner as the operation in the atmosphere, and the pitching and yawing of the moving table were in the submicron range.

The support 1 and the moving table 8 are provided on a moving table that moves in a direction orthogonal to the moving direction, and a rotary table is provided on the moving table 8 to perform semiconductor thin film processing, inspection, etc. on the rotary table. Can be done. Further, in the above-mentioned embodiment, the guide rollers 17a and 17b shown in FIGS. 1 and 2 are connected to the first and second guide shafts 5a and 5a.
5b from the inside, and the second guide roller 17b is moved by the compression spring 27 in the direction in which the second guide roller 17b is separated from the first guide roller 17a.
Of the first and second guide rollers 17a by applying pressure to the guide shaft 5b of
And 17b cooperate to provide first and second guide shafts 5a and 5
The first guide roller 17a and the second guide roller 17b are engaged with the first and second guide shafts 5a and 5b from the outside so that the second guide roller 17b is held so as to protrude.
17b is pressed against the second guide shaft 5b by a compression spring in a direction approaching the first guide roller 17a, and the first and second guide rollers 17a and 17b cooperate with each other to form the first and second guide shafts 5a.
You may make it hold so that 5 and 5b may be pinched.
Then, by using the guide mechanism in which the first and second guide rollers 17a and 17b hold the first and second guide shafts 5a and 5b in this manner, the moving table 8 and the like can be provided as in the above embodiment. Not only in the case of moving in the horizontal direction, but also in the vertical direction, the inverted horizontal direction, the tilt direction, etc.
It can be moved in any posture.

EFFECTS OF THE INVENTION As described above, according to the present invention, the drive device can drive the moving table by the guides of the first and second guide shafts and the first and second guide rollers via the power transmission means. it can. Then, the second guide roller is supported on the moving table by using a spring so as to absorb thermal strain, and the first and second guide rollers are made to cooperate with each other to be held by the first and second guide shafts. In this way, since the driving device and the moving table are linked by the power transmission means using the spring so as to absorb the thermal strain, when the vacuum chamber is heated and the gas is degassed, the above-mentioned members are subjected to the thermal strain ( Even if thermal expansion occurs, this can be absorbed. Particularly, since the second guide roller side is biased by the spring, not the second guide shaft side as described above, when the reference side first guide shaft is mounted with sufficient accuracy, The local distortion of the guide shaft can be sufficiently covered by a spring motion of the second guide roller by a suspension movement. Therefore, it can be operated smoothly and with high accuracy without fear of damage in an ultra-high vacuum environment of 10 ^-11 Torr level, and after cooling, each member automatically returns to the state before heating. Can be made. Further, the first and second guide rollers are configured with grooves so that they are engaged with the first and second cylindrical guide grooves, and as described above, the second guide roller is heated by the moving table. A first and a second guide roller are supported by a spring so as to absorb strain, and the first and second guide rollers cooperate with each other.
Since it is held by the guide shafts of the first and second guide rollers and the first and second guide rollers even if the moving table is set in any posture such as horizontal direction, vertical direction, or inverted horizontal direction. The guide shaft can be reliably held in the engaged state. Therefore, in the ultra-high vacuum environment, the moving table can be moved smoothly in any posture in the same manner as in the atmosphere.
Moreover, it can be operated with high accuracy. Further, since the first and second guide rollers are formed so as to have a groove that is symmetrical and expands in a conical shape on both sides from the central portion along the axial direction, the first and second cylindrical rollers are formed. Assembly and adjustment work with the guide shaft can be easily performed.

[Brief description of drawings]

1 to 5 show an ultrahigh vacuum table according to an embodiment of the present invention. FIG. 1 is a plan view, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 1 is a sectional view taken along the line III-III in FIG. 1, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, and FIG.
FIG. 5 is a sectional view taken along the line VV in the figure. 1 ... Support base, 5a, 5b ... Guide shaft, 8 ... Moving table, 11a, 11b ... Support block, 17a, 17b ... Guide roller, 27 ... Compression spring, 30 ... Stepping motor, 38 ...
… Screw shafts, 43,44… nuts.

Claims (1)

[Claims] 1. A pair of first and second cylindrical guide shafts arranged in parallel, a moving table which moves along the first and second guide shafts, and the first and second guide shafts. Each of the guide shafts is rotatably engaged with the guide shaft, and is formed with a groove that expands in a conical shape symmetrically on both sides from the central portion along the axial direction. The movable table is guided by the first and second guides. First and second guide rollers for moving along the axis, supporting means for rotatably supporting the first guide roller at a fixed position, and the second guide roller by a spring for the second guide roller. Supporting means for pressing the guide shaft and holding the first and second guide rollers on the first and second guide shafts so that the first and second guide rollers cooperate with each other to absorb thermal strain, and for moving the moving table. The drive unit, the drive unit and the moving table Ultra-high vacuum table, characterized in that it comprises a power transmission means which are associated so as to absorb the thermal distortion with.