JPH1116979A - Vacuum chamber and mounting table device for semiconductor processing - Google Patents

Abstract

(57) [Problem] To prevent runaway of a movable member due to an urging force caused by a pressure difference between the inside and outside of a vacuum chamber and runaway due to its own weight. A mounting table is provided in a vacuum processing chamber so as to be vertically movable. A lead screw mechanism 86 is provided in parallel with the ball screw mechanism 80 for transmitting the driving force to the mounting table 5. Ball screw mechanism 80 and lead screw mechanism 86
Are driven by a motor 96 via a belt 95 and are given the same feed amount. Shaft 8 of lead screw mechanism 86
7, stoppers 91 and 92 are provided. Stopper 91
When the mounting table 5 rises due to the urging force caused by the pressure difference between the inner and outer spaces of the processing chamber 3 when the belt 95 is broken, the mounting table 5 comes into contact with the mounting table 5 to prevent runaway. Stopper 92
When the belt 95 is broken and the mounting table 5 falls due to its own weight, the mounting table 5 comes into contact with the mounting table 5 to prevent runaway.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum chamber and a mounting table device for semiconductor processing, and more specifically, to a runaway of a movable member receiving an urging force caused by a pressure difference between an inner space and an outer space of a vacuum chamber, and to a mounting table. The present invention relates to a technique for preventing runaway of a mounting table of a device due to its own weight. Here, the semiconductor processing refers to forming a semiconductor layer, an insulating layer, a conductive layer, and the like in a predetermined pattern on a substrate to be processed such as a semiconductor wafer or an LCD substrate, thereby forming a semiconductor device or a semiconductor on the substrate. It means various processes performed to manufacture a structure including wiring, electrodes, and the like connected to the device.

[0002]

2. Description of the Related Art Vacuum chambers are used in various situations such as an etching apparatus, a film forming apparatus, a heat treatment apparatus, a load lock apparatus, and the like for performing semiconductor processing on a substrate to be processed such as a semiconductor wafer or an LCD substrate. . In this type of vacuum chamber, a driving source for driving a movable member inside the chamber is usually disposed outside the chamber from the viewpoint of reducing exhaust capacity, preventing contamination, protecting a driving system, and the like. However, in particular, when the movable member forms a vacuum space in cooperation with the casing, the movable member receives an urging force caused by a pressure difference between the inner and outer spaces, which causes various problems.

A typical example is a vacuum processing chamber having a vertically movable mounting table used in a parallel plate type etching apparatus or the like. FIG. 6 is a diagram schematically showing a conventional structure around a susceptor (mounting table) and its operation in a parallel plate type etching apparatus.

[0006] As shown in FIG.
Inside the susceptor 15 which functions as a lower electrode and a mounting table
2 and an upper electrode 153 opposed thereto.
Between the susceptor 152 and the bottom of the casing 151,
A ball screw mechanism 154 that transmits a driving force for moving the susceptor 152 up and down is provided. The ball screw mechanism 154 has a ball screw shaft 156 connected to the susceptor 152, and a ball screw nut 157 pivotally supported by the bottom of the casing 151 and engaging with the ball screw shaft 156. Ball screw nut 157
Is driven to rotate by a motor 159 via a belt 158.

An expandable and contractable bellows 161 is hermetically connected between the susceptor 152 and the bottom of the casing 151. Therefore, the upper surface of the susceptor 152 is exposed to the vacuum atmosphere in the vacuum processing chamber, while the rear surface of the susceptor 152 is isolated from the vacuum atmosphere by the bellows 161 and is exposed to the atmospheric pressure atmosphere together with the driving system. Therefore, the susceptor 152 is in a state where the urging force 162 is constantly applied due to the pressure difference between the inner and outer spaces of the vacuum processing chamber.
For example, when the susceptor 152 is for a 300 mm (12 inch) wafer, its weight is about 200 kg and the pressure in the vacuum processing chamber is 10 mTorr.
The urging force 162 applied to the susceptor 152 when the pressure is set to 100 mTorr is as large as 1900 kg. However, since the motor 159 is connected to the ball screw mechanism 154 via the belt 158, the susceptor 1
52 can be stopped at a position restrained by the motor 159.

However, for example, when the belt 158 is broken due to fatigue or the like, the susceptor 152 is released from the constraint of the motor 159, and the force opposing the urging force 162 is the own weight of the susceptor 152 and the frictional force on the screw surface of the ball screw mechanism 154. Only. However, the ball screw mechanism 154
Rather, it is characterized in that there is almost no frictional force on the screw surface and the driving force can be transmitted with high efficiency, so that it cannot function as a stopper. Therefore, when the constraint of the motor 159 is released, the susceptor 15
2 rises at a high speed by the urging force 162 caused by the differential pressure, and collides with the upper electrode 153 as shown in FIG. As a result, the susceptor 152 itself and the upper electrode 153
Can be damaged, making the device unusable.

Conversely, if the belt 158 is broken and the susceptor 152 is released from the restraint of the motor 159 in a state where the pressure in the vacuum processing chamber is returned to the normal pressure, the susceptor 152 falls by its own weight. , Causing a problem of damage.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is directed to a vacuum chamber having a movable member which receives an urging force caused by a pressure difference between an inner space and an outer space. An object is to prevent runaway of a movable member due to an urging force. Another object of the present invention is to prevent a mounting table having a heavy weight mounting table from falling due to its own weight.

[0009]

SUMMARY OF THE INVENTION A first aspect of the present invention is as follows.
A casing for forming a first space set in a reduced-pressure atmosphere in the semiconductor processing vacuum chamber and isolating the first space from a second space having a higher pressure than the first space; A movable member attached to the casing so as to be movable relative to the casing while transmitting the driving force for moving the movable member relative to the casing; To connect the casing and the movable member, a ball screw mechanism having a ball screw shaft and a ball screw nut, a lead screw shaft which is arranged in parallel with the ball screw shaft and has an axis parallel to the ball screw shaft, and A lead screw nut pivotally supported on the casing and screwed to the lead screw shaft; A lead screw mechanism, a common drive mechanism for applying power to the ball screw mechanism and the lead screw mechanism, and the drive mechanism applies substantially the same feed amount to the ball screw shaft and the lead screw shaft. A stopper disposed on the lead screw shaft; and the stopper is configured such that the driving mechanism is broken, and the movable member is moved by the urging force caused by a pressure difference between the first and second spaces. When moving to the first space side relative to the lead screw shaft,
The movable member or a member that moves integrally with the movable member, and is arranged to prevent runaway of the movable member.

According to a second aspect of the present invention, in the semiconductor processing vacuum chamber according to the first aspect, the driving mechanism applies power to the ball screw mechanism and the lead screw mechanism via a common power transmission band. It is characterized by having a common motor for applying.

According to a third aspect of the present invention, in the semiconductor processing vacuum chamber according to the second aspect, the ball screw nut is pivotally supported with respect to the casing, and the ball screw nut and the lead screw nut are connected to the power transmission band. Is directly driven to rotate.

According to a fourth aspect of the present invention, in the semiconductor processing vacuum chamber according to any one of the first to third aspects, a guide hole is provided in the movable member, and the lead screw shaft is provided only in the axial direction thereof. It is movably inserted into the guide hole.

According to a fifth aspect of the present invention, in the semiconductor processing vacuum chamber according to any one of the first to fourth aspects, the movable member mounts a substrate to be processed on which semiconductor processing is performed in the vacuum chamber. It is a mounting table for mounting.

According to a sixth aspect of the present invention, in a mounting table device for semiconductor processing, a mounting table for mounting a substrate to be processed, a support frame disposed below the mounting table, and the support frame. A ball screw mechanism having a ball screw shaft and a ball screw nut for connecting the support frame and the mounting table so as to transmit a driving force for vertically moving the mounting table with respect to the ball screw shaft, A lead screw shaft having an axis parallel to the ball screw shaft and a lead screw nut pivotally supported by the support frame and screwing to the lead screw shaft; and A common drive mechanism for applying power to the lead screw mechanism, and the ball The dishaft and the lead screw shaft are provided with substantially the same feed amount, and the stopper disposed on the lead screw shaft, and the stopper is such that the driving mechanism is destroyed and the load of the mounting table is When the mounting table moves relatively downward with respect to the lead screw shaft, the mounting table abuts on the mounting table or a member that moves integrally therewith, and is arranged to prevent runaway of the mounting table. And characterized in that:

According to a seventh aspect of the present invention, in the semiconductor processing platform according to the sixth aspect, the driving mechanism includes a power transmitting band common to the ball screw mechanism and the lead screw mechanism. The mounting table device for semiconductor processing according to claim 6, further comprising a common motor for applying a force.

According to an eighth aspect of the present invention, in the mounting table device for semiconductor processing according to the sixth or seventh aspect, a guide hole is provided in the mounting table, and the lead screw shaft can move only in the axial direction. And is inserted into the guide hole.

[0017]

FIG. 1 is a sectional view showing a plasma etching apparatus 1 incorporating a vacuum chamber and a mounting table according to an embodiment of the present invention. The processing space 2 of the etching apparatus 1 is formed in a vacuum processing chamber 3 formed of a cylindrical casing that can be hermetically closed. The casing of the processing chamber 3 is made of aluminum or the like, the surface of which is anodized, and is grounded via a grounding wire 4. The mounting table 5 which is a movable member according to the present invention is supported on the bottom of the processing space 2 by a motor 96 so as to be movable in a vertical direction in a manner described later. The mounting table 5 includes a motor 96.
And a susceptor 6 mounted thereon via an insulating plate 8 made of ceramic or the like.

The susceptor 6 has a substantially columnar shape, provides a mounting surface for mounting the semiconductor wafer W, and constitutes a lower electrode. The susceptor 6 is made of aluminum whose surface is anodized. The susceptor 6 includes a heating means (not shown) such as a ceramic heater and a refrigerant circulation path (not shown) for circulating the refrigerant with an external refrigerant source (not shown). A temperature adjusting means is provided, so that the wafer W on the susceptor 6 can be maintained at a predetermined temperature. The temperature of the wafer W is automatically controlled by a temperature sensor (not shown) and a temperature control mechanism (not shown).

On the susceptor 6, an electrostatic chuck 11 for holding the wafer W by suction is provided. The electrostatic chuck 11 has a configuration in which a conductive thin film 12 is sandwiched between polyimide resins 13 from above and below. Processing chamber 3
When a voltage from a high-voltage DC power supply 14 installed outside of the device, for example, a voltage of 1.5 kV to 2 kV is applied to the thin film 12, the wafer W is placed on the upper surface of the electrostatic chuck 11 by Coulomb force generated at that time. Adsorbed and held.

In the susceptor 6, a plurality of lifter pins 20, for example, three lifter pins 20 are provided as support members for transferring the wafer W onto and from the electrostatic chuck 11. The lifter pins 20 move up and down relatively as the susceptor 6, and the wafer W
Can be lifted up from above the electrostatic chuck 11.

On the periphery of the susceptor 6, the electrostatic chuck 1
An inner focus ring 21 having a substantially annular flat surface is provided so as to surround the first focus ring 21. The inner focus ring 21 is made of conductive single crystal silicon,
Thus, the ions in the plasma can be effectively incident on the wafer W.

On the outer periphery of the inner focus ring 21, an outer focus ring 22 having a substantially annular flat surface is provided.
The outer focus ring 22 is made of quartz, which is an insulator, and the upper edge of the outer periphery of the outer focus ring 22 is configured to smoothly discharge a gas formed into a curved shape that is convex outward. The outer focus ring 22, together with a shield ring 53 described later, can suppress diffusion of plasma generated between the susceptor 6 and an electrode plate 51 described later.

A baffle plate 23 made of, for example, an insulating material is provided around the susceptor 6. Baffle plate 2
3 is fixed to the susceptor 6 by means such as bolts via a quartz support or the like. Therefore, the susceptor 6
The baffle plate 23 also moves up and down with the up and down movement of. A large number of through holes 23a are formed in the baffle plate 23, so that gas can be uniformly discharged.

A shower head 30 that functions as an upper electrode facing the susceptor 6 and that introduces an etching gas or another gas into the processing space 2 is disposed above the processing space 2. The shower head 30 includes a cooling member 32 made of aluminum, which is attached to a ceiling of the processing chamber 3 via an insulating support member 31, and a cooling member 3.
2 and a diffusion member 33 fixedly supported. A refrigerant circulation path 34 is formed in an upper part in the cooling member 32. By circulating the chiller (refrigerant) supplied from the outside in the refrigerant circulation path 34, an electrode plate 51 described later can be cooled to a predetermined temperature.

The diffusion member 33 has a hollow structure having two upper and lower baffle plates 35 on the lower side. A large number of diffusion holes 35a are formed in each of the upper and lower two-stage baffle plates 35 so as not to overlap vertically. A gas inlet 36 is provided at the center of the diffusion member 33, and a gas inlet pipe 38 is connected via a valve 37. Gas supply sources 43 and 44 are connected to the gas introduction pipe 38 via valves 39 and 40 and mass flow controllers 41 and 42 for flow rate adjustment, respectively. An inert gas such as Ar is supplied from a gas supply source 43, and a reactive gas such as C ₄ F ₈ is supplied from a gas supply source 44.

On the lower surface of the cooling member 32, a cooling plate 50 having a large number of discharge ports 50a is in close contact. An electrode plate 51 is tightly fixed to the lower surface of the cooling plate 50 so as to face the susceptor 6. The electrode plate 51 is made of conductive single-crystal silicon, is attached to the periphery of the lower surface of the cooling plate 50 by bolts (not shown), and is electrically connected to the cooling plate 50. The electrode plate 51 also has a number of discharge ports 51 a formed therein, and communicates with the discharge ports 50 a of the cooling plate 50. Therefore, the gas inside the diffusion member 33 is
0a and the discharge port 51a of the electrode plate 51, the liquid is uniformly discharged onto the wafer W on the electrostatic chuck 11.

A shield ring 53 is provided around the lower surface of the electrode plate 51 so as to cover a fixing bolt (not shown). The shield ring 53 is made of quartz, which is an insulator, and forms a gap narrower than the gap between the electrostatic chuck 11 and the electrode plate 51 in cooperation with the outer focus ring 22 to suppress plasma diffusion. Between the upper end of the shield ring 53 and the ceiling of the processing chamber 3,
An insulating ring 54 is provided.

A pressure sensor 55 for detecting the degree of vacuum in the processing chamber 3 is mounted on a side surface of the processing chamber 3.
The detection signal of the degree of vacuum detected by the sensor 55 is input to the controller 74, and the degree of vacuum in the processing chamber 3 is constantly monitored.

An evacuation pipe 62 is connected to the lower part of the processing chamber 3 and communicates with evacuation means 61 such as a vacuum pump. The inside of the processing space 2 can be evacuated to an arbitrary degree of vacuum, for example, between 10 mTorr and 100 mTorr, by the evacuation unit 61 via the baffle plate 23 disposed around the susceptor 6.

To the susceptor 6 serving as the lower electrode, RF power having a frequency of about several hundred kHz, for example, 800 kHz, is supplied from the RF power source 63 via the matching unit 64.
For the shower head 30 serving as the upper electrode, an RF power of a frequency of 1 MHz or higher, for example, 27.12 MHz, whose frequency is higher than that of the RF electrode 63, is supplied from the RF power source 66 to the matching unit 65, the cooling member 32, and the cooling plate 50. Supplied via

A load lock chamber 72 is adjacent to the outside of the processing chamber 3 via a gate valve 71. In the load lock chamber 72, a transfer means 73 such as a transfer arm is provided for transferring the wafer W, which is a substrate to be processed, to and from the processing space 2 in the processing chamber 3.

In the control system of the etching apparatus 1, a high-voltage DC power supply 14, lifter pins 20 in the susceptor 6, valves 39 and 40, mass flow controllers 41 and 42, vacuum exhaust means 61, RF power supplies 63 and 66, and the mounting table 5
The motors 96 for moving the (susceptor 6) up and down are controlled by the controllers 74, respectively.

As shown in FIG. 2, a ball screw mechanism 80 for transmitting a driving force for moving the mounting table 5 up and down is disposed between the mounting table 5 and the bottom of the processing chamber 3.
The ball screw mechanism 80 has a ball screw shaft 81 connected to the mounting table 5, and a ball screw nut 82 pivotally supported by the bottom of the processing chamber 3 and engaging with the ball screw shaft 81.

The ball screw shaft 81 is vertically oriented, and its upper end is attached to the center of the base plate 7a of the holder 7 of the mounting table 5 via the boss 83. The boss 83 restrains the ball screw shaft 81 so that the ball screw shaft 81 is fixed to the mounting table 5 in both the axial direction and the rotation direction.

The ball screw nut 82 is connected to the processing chamber 3.
Is supported by a bearing 84 attached to the bottom of the. A pulley 85 is integrally formed with the ball screw nut 82 so as to be exposed to the outside from the bottom of the processing chamber 3.

A lead screw mechanism 86 for preventing runaway of the mounting table 5 is provided between the mounting table 5 and the bottom of the processing chamber 3. The lead screw mechanism 86 has a lead screw shaft 87 whose upper part engages with the mounting table 5, and a lead screw nut 88 pivotally supported by the bottom of the processing chamber 3 and engages with the lead screw shaft 87.

The lead screw mechanism 86 is set so as to satisfy a known self-sustaining condition so that the screw is not reversed by an external force in the axial direction. Here, the self-supporting condition means that the lead angle β and the friction angle ρ on the screw surface satisfy the relationship β ≦ ρ. The lead screw mechanism 86 is preferably formed of a metric trapezoidal screw from the viewpoint of preventing the screw from being reversely rotated by an external force in the axial direction. Also, the lead screw mechanism 86
Are set to have the same screw pitch as the ball screw mechanism 80. Even if the screw pitches of the lead screw mechanism 86 and the ball screw mechanism 80 are different, the feed amounts of both mechanisms can be made equal by adjusting the number and diameter of the pulley teeth.

The lead screw shaft 87 is vertically oriented so as to have an axis parallel to the ball screw shaft 81, and is juxtaposed to the ball screw shaft 81. A small-diameter smooth shaft portion 87a is formed on the upper portion of the lead screw shaft 87. The smooth shaft portion 87a penetrates a hole 7b formed in the base plate 7a of the holder 7 of the mounting table 5, and reaches the internal space 7c of the mounting table 5. A slide bearing 89 that defines a guide hole is fixed to the hole 7b, and the smooth shaft portion 87a of the lead screw shaft 87 is inserted into the guide hole. The lead screw shaft 87 is fixed in the rotation direction with respect to the mounting table 5, so that the lead screw shaft 87 is relatively movable only in the axial direction, that is, in the vertical direction with respect to the mounting table 5.

The base plate 7a of the holder 7 of the mounting table 5 is attached to the smooth shaft portion 87a of the lead screw shaft 87.
The upper stopper 91 and the lower stopper 92 are fixed so as to sandwich the bearing 89 therebetween. Small gaps M1 and M are provided between the upper stopper 91 and the base plate 7a and between the lower stopper 92 and the lower surface of the bearing 89, respectively.
2 are formed. Accordingly, when the position of the mounting table 5 is shifted relative to the lead screw shaft 87 vertically upward by the gap M1, the upper stopper 91 and the base plate 7a come into contact with each other, thereby preventing further positional shift. When the position of the mounting table 5 is shifted relative to the lead screw shaft 87 vertically downward by the gap M2, the lower stopper 9
2 and the bearing 89 are in contact with each other to prevent further displacement.

The lead screw nut 88 is connected to the processing chamber 3.
Is supported by a bearing 93 attached to the bottom of the. A pulley 94 is integrally formed with the lead screw nut 88 so as to be exposed from the bottom of the processing chamber 3 to the outside.

The pulleys 85 and 94 of the ball screw nut 82 and the lead screw nut 88 are disposed outside the processing chamber 3 via a common power transmission band, for example, a V-belt 95 hung in the manner shown in FIG. The motor 96 is driven to rotate by a pulley 96a. As described above, since the ball screw mechanism 80 and the lead screw mechanism 86 have the same screw pitch and are driven via the common belt 95,
The ball screw shaft 81 and the lead screw shaft 87 are given substantially the same feed amount by one rotation of the motor 96. Even if the screw pitches of the two screw mechanisms 80 and 86 are different, the feed amounts of the two mechanisms can be made equal by adjusting the number of teeth and the diameter of the pulley.

A guide mechanism 97 for assisting the vertical movement of the mounting table 5 is further provided between the mounting table 5 and the bottom of the processing chamber 3. The guide mechanism 97 has a guide shaft 98 whose tip is connected to the mounting table 5 and is vertically oriented, and a slide bearing 99 mounted on the bottom of the processing chamber 3 and engaged with the guide shaft 98.
And

In the embodiment shown in FIGS. 1 and 2, the guide mechanism 97 can be omitted.
This is because the lead screw mechanism 86 for preventing the runaway of the mounting table 5 also functions as a guide for assisting the vertical movement of the mounting table 5. In the embodiment shown in FIGS. 1 and 2,
Although one ball screw mechanism 80 and one lead screw mechanism 86 are provided, each of the two screw mechanisms 80 and 86 is provided in plural (for example, two, three, or different numbers).
Can be used. When the same number of the two screw mechanisms 80 and 86 are used, it is desirable that the two screw mechanisms 80 and 86 are alternately arranged at equal intervals along the circumferential direction of the mounting table 5 in consideration of the support balance of the mounting table 5.

A telescopic bellows 102 is hermetically connected between the mounting table 5 and the bottom of the processing chamber 3. The bellows 102 surrounds the ball screw mechanism 80, the lead screw mechanism 86, and the guide mechanism 97, is isolated from the processing space 2 in the processing chamber 3, and is arranged so as to be placed under an atmospheric pressure atmosphere.

FIG. 4 is a diagram schematically showing a structure around the mounting table 5 of the etching apparatus 1 according to the present embodiment and its operation. The mounting table 5 is frequently moved up and down by a motor 96 via a ball screw mechanism 80 in order to load and unload the wafer W to and from the susceptor 6 and to set an interval between the susceptor 6 and the shower electrode 30. At this time, the ball screw mechanism 80 and the lead screw mechanism 86 share a common belt 95.
And the same feed amount is applied to the ball screw shaft 81 and the lead screw shaft 87, so that the relative positional relationship in the vertical direction is always kept constant as shown in FIG. Accordingly, the ball screw shaft 81 transmits the driving force to the mounting table 5, while the lead screw shaft 87 moves the minute gaps M 1 and M with respect to the mounting table 5.
2 and functions only as a guide for the mounting table 5.

As described above, the upper surface of the mounting table 5 is exposed to the processing space 2 in the processing chamber 3, while the lower surface of the mounting table 5 is exposed to the atmospheric pressure atmosphere by being separated by the bellows 102. For this reason, when the processing space 2 is set to a pressure of 10 mTorr to 100 mTorr for the etching process, the mounting table 5 is in a state where the urging force 104 is applied to the mounting table 5 due to the pressure difference between the inner and outer spaces of the processing chamber 3. Becomes For example, when the mounting table 5 is for a 300 mm (12 inch) wafer, its weight is about 200 kg, whereas the urging force 104 applied to the mounting table 5 is very large, 1900 kg. However, the motor 96 is
The mounting table 5 can be stopped at a position restrained by the motor 96 because the mounting table 5 is connected to the ball screw mechanism 80 via the.

However, during the etching process, for example, as shown in FIG. 4B, if the portion 95a of the belt 95 is broken by fatigue or the like, the mounting table 5 is released from the restraint of the motor 96, and the load caused by the differential pressure is applied. Processing space 2 by power 104
Start climbing to the side. However, at this time, since the lead screw shaft 87 stops and is fixed due to the breakage of the belt 95, when the mounting table 5 is relatively raised with respect to the lead screw shaft 87 by the gap M1, the upper stopper 91 is stopped. And the base plate 7a (see FIG. 2) of the holder 7 abuts. Therefore, the mounting table 5 is prevented from further rising,
Runaway of the mounting table 5 can be prevented.

When such a trouble occurs, the processing space 2 is returned to normal pressure, that is, atmospheric pressure. Then
The mounting table 5 starts to fall under its own weight 106 of 200 kg. However, the mounting table 5 has the lead screw shaft 87
The lower stopper 92 and the bearing 89 (refer to FIG. 2) come into contact with each other when they fall relatively to the gap M1 and pass through the initial position, and further fall therefrom by the gap M2. For this reason, it is possible to prevent the mounting table 5 from dropping further and prevent the mounting table 5 from running away. In a case where the processing chamber space 2 is returned to the normal pressure, the belt 95 is broken and the mounting table 5 is dropped. Similarly, the lower stopper 92 and the bearing 89 come into contact with each other.
Runaway of the mounting table 5 can be prevented.

FIG. 5 is a view schematically showing a structure around a mounting table 110 of a mounting table apparatus according to another embodiment of the present invention and its operation. In FIG. 5, the same members as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The feature of this embodiment is that the ball screw mechanism 112 for transmitting the driving force for moving the mounting table 110 up and down is different from the ball screw mechanism 80 of the previous embodiment. That is, the ball screw mechanism 112 extends between the upper and lower support frames 121 and 122 and is pivotally supported by the two frames 121 and 122.
3 and the ball screw nut 11 built in the mounting table 110
4 The pulley 11 is attached to the ball screw shaft 113 so as to be exposed downward from the lower support frame 122.
5 are integrally formed, and the pulley 115 is driven to rotate by the motor 96. Therefore, in the case of this embodiment, the vertical position of the ball screw shaft 113 is fixed,
The mounting table 110 is moved up and down along the ball screw shaft 113.

On the other hand, a lead screw mechanism 86 for preventing runaway of the mounting table 110 has a lead screw shaft 87 and a lead screw nut 88 having the same structure and arrangement as those of the previous embodiment. That is, the lead screw mechanism 86
The ball screw mechanism 112 is oriented so as to satisfy the self-sustaining condition, have the same screw pitch as the ball screw mechanism 112, and have an axis parallel to the ball screw mechanism 112.

The upper part of the lead screw shaft 87 is inserted into the guide portion 111 of the mounting table 110 so as to be movable only in the axial direction, that is, in the vertical direction with respect to the mounting table 110. A mounting table 110 is provided above the lead screw shaft 87.
The upper stopper 91 and the lower stopper 92 are fixed so as to sandwich the guide portion 111 through the small gaps M1 and M2. On the other hand, the lead screw nut 88 has a pulley 9
4 are integrally formed, and together with the pulley 115 of the ball screw mechanism 111, a common power transmission band, for example, a V belt 9
5, and is rotated by a motor 96.

Also in the embodiment shown in FIG. 5, when the belt 95 is broken due to fatigue or the like, the mounting table 110 is released from the restraint of the motor 96 and starts to move up or down by the upward urging force or its own weight. However, at this time, the lead screw shaft 87 stops due to the destruction of the belt 95,
Since it is fixed, upper and lower stoppers 91, 92
However, when the position of the mounting table 110 is relatively shifted by the gaps M1 and M2, the mounting table 110 contacts the guide portion 111. Therefore,
Further lifting or lowering of the mounting table 110 can be prevented, and runaway of the mounting table 110 can be prevented.

In the embodiment shown in FIGS. 2 and 5, the stoppers 91 and 92 are disposed so as to directly contact a part of the mounting tables 5 and 110 to prevent runaway of these. However, the stoppers 91 and 92 are
When the position shifts relative to the lead screw shaft 87, it may be disposed so as to abut on a member that moves integrally therewith. For example, in the embodiment shown in FIG. 2, since the ball screw shaft 81 and the boss 83 always move integrally with the mounting table 5, the stoppers 91, 92
Is arranged so as to be in contact with these members, runaway of the mounting table 5 can be prevented.

In the embodiment shown in FIGS. 2 and 5, the power from the motor 96 is supplied to the ball screw mechanisms 80, 1 and 2.
A combination of a V-belt 95, which is a common power transmission band, and pulleys 85, 115, 94, which are driven rotators, is used for transmission to the lead screw mechanism 86 and the lead screw mechanism 86. Instead of such a power transmission mechanism, a flat belt, a timing belt, or a chain may be used as a common power transmission band, and correspondingly, the driven rotor may be of another type.

The semiconductor processing vacuum chamber and the mounting table apparatus according to the present invention include various apparatuses other than the above-described etching apparatus, such as a film forming apparatus, a heat treatment apparatus, a load lock apparatus, an inspection apparatus, a coating apparatus, and a cleaning apparatus. Can be applied to As a processing target, in addition to a semiconductor wafer, for example, an LCD substrate can be used as a substrate to be processed.

[0057]

According to the vacuum chamber of the present invention, the lead screw mechanism is arranged in parallel with the ball screw mechanism for transmitting the driving force with high efficiency under a specific condition, thereby causing the pressure difference between the inner and outer spaces. Runaway of the movable member when a trouble occurs can be prevented without hindering the normal operation of the movable member receiving the urging force.

According to the mounting table apparatus of the present invention, the lead screw mechanism is arranged in parallel with the ball screw mechanism for transmitting the driving force with high efficiency under specific conditions, so that the normal operation of the heavy mounting table can be achieved. Can be prevented from falling due to the weight of the mounting table when a trouble occurs.

Further, by inserting the shaft of the lead screw mechanism into the guide hole of the movable member or the mounting table so as to be movable only in the axial direction, the lead screw mechanism can also serve as the guide mechanism that was conventionally required. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a plasma etching apparatus incorporating a vacuum chamber and a mounting table apparatus according to an embodiment of the present invention.

FIG. 2 is a partial sectional view showing details of a mechanism for driving a mounting table of the etching apparatus shown in FIG. 1;

FIG. 3 is a side view showing a positional relationship between a belt, a ball screw mechanism, a lead screw mechanism, and a pulley of a motor.

FIG. 4 is a diagram schematically showing a structure around a mounting table of the etching apparatus shown in FIG. 1 and its operation.

FIG. 5 is a diagram schematically showing a structure around a mounting table of a mounting table apparatus according to another embodiment of the present invention and its operation.

FIG. 6 is a view schematically showing a structure around a mounting table of a conventional etching apparatus and its operation.

[Explanation of symbols]

3 vacuum processing chamber, 5 mounting table, 6 susceptor (lower electrode), 30 shower head (upper electrode), 110
載 Mounting table, 80, 112 １１２ Ball screw mechanism, 81, 11
3 ... ball screw shaft, 82, 114 ... ball screw nut, 86 ... lead screw mechanism, 87 ... lead screw shaft, 88 ... lead screw nut, 91, 92 ... stopper,
95 belt, 96 motor, 97 guide mechanism, 10
2 ... Bellows.

Claims (8)

[Claims] 1. A casing for forming a first space set in a reduced-pressure atmosphere and isolating the first space from a second space having a higher pressure than the first space, and cooperating with the casing. A movable member attached to the casing so as to be movable relative to the casing, and a driving force for moving the movable member relative to the casing. A ball screw mechanism having a ball screw shaft and a ball screw nut for connecting the casing and the movable member; a lead screw shaft having an axis arranged in parallel with the ball screw shaft and parallel to the ball screw shaft; and the casing. A lead screw mechanism pivotally supported with respect to and having a lead screw nut screwed into the lead screw shaft; A common drive mechanism for applying power to the ball screw mechanism and the lead screw mechanism, the ball screw shaft and the lead screw shaft being given substantially the same feed amount by the drive mechanism, and A stopper disposed on the screw shaft and the stopper are configured such that the driving mechanism is broken, and the movable member is moved relative to the lead screw shaft by an urging force caused by a pressure difference between the first and second spaces. And relatively the first
Abutting the movable member or a member that moves integrally therewith when moving to the space side, and disposing the movable member so as to prevent runaway of the movable member. Vacuum chamber. 2. The apparatus according to claim 1, wherein said drive mechanism includes a common motor for applying power to said ball screw mechanism and said lead screw mechanism via a common power transmission band. 7. The vacuum chamber for semiconductor processing according to claim 1. 3. The semiconductor processing apparatus according to claim 2, wherein said ball screw nut is pivotally supported with respect to said casing, and said ball screw nut and said lead screw nut are directly driven to rotate by said power transmission band. For vacuum chamber. 4. The movable member is provided with a guide hole, and the lead screw shaft is inserted into the guide hole so as to be movable only in the axial direction. 7. The vacuum chamber for semiconductor processing according to item 1. 5. The apparatus according to claim 1, wherein the movable member is a mounting table for mounting a substrate to be processed on which semiconductor processing is performed in the vacuum chamber. Vacuum chamber for semiconductor processing. 6. A mounting table for mounting a substrate to be processed, a support frame disposed below the mounting table, and a drive for vertically moving the mounting table with respect to the support frame. A ball screw mechanism having a ball screw shaft and a ball screw nut for connecting the support frame and the mounting table so as to transmit a force; and a lead having an axis arranged in parallel with the ball screw shaft and parallel to the ball screw shaft. A lead screw mechanism having a screw shaft and a lead screw nut pivotally supported by the support frame and screwed to the lead screw shaft; and a common drive mechanism for applying power to the ball screw mechanism and the lead screw mechanism. And the drive mechanism causes the ball screw shaft and the lead screw shaft to be substantially the same. The feed amount is given, and the stopper disposed on the lead screw shaft, and the stopper, the driving mechanism is broken, and the load of the mounting table causes the mounting table to move with respect to the lead screw shaft. The semiconductor device is arranged so as to abut on the mounting table or a member moving integrally therewith when moving relatively downward to prevent runaway of the mounting table. Mounting table device for processing. 7. The apparatus according to claim 6, wherein said drive mechanism includes a common motor for applying power to said ball screw mechanism and said lead screw mechanism via a common power transmission band. A mounting table device for semiconductor processing as described in the above. 8. The guide hole according to claim 6, wherein a guide hole is provided in the mounting table, and the lead screw shaft is inserted into the guide hole so as to be movable only in the axial direction. Mounting table device for semiconductor processing.