JP3452422B2 - Vacuum processing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates, on the vacuum processing apparatus.

[0002]

2. Description of the Related Art As a vacuum processing apparatus for performing a predetermined process on an object to be processed under a reduced pressure atmosphere, for example, an ion implantation apparatus, an etching apparatus, an ashing apparatus, a sputtering apparatus, a reduced pressure CV.
D device and the like are known. As such a vacuum processing apparatus, a vacuum preparatory chamber is provided in the vacuum preparatory chamber through a valve, and the valve is opened in the object to be treated housed in the vacuum preparatory chamber so that the vacuum preparatory chamber has a predetermined space. Some have been designed to be processed.

According to the above vacuum processing apparatus, while the vacuum processing chamber is maintained at a predetermined vacuum degree, only the vacuum preliminary chamber is returned to normal pressure to carry in and carry out the object to be processed, and the object to be processed is loaded into the vacuum preliminary chamber. When the vacuum chamber is housed and the vacuum degree is the same as that of the vacuum processing chamber, a predetermined process can be directly performed on the object to be processed in the vacuum preliminary chamber from the vacuum processing chamber side only by opening the valve. Therefore, it is possible to further improve the processing capacity and the like as compared with the case where the object to be processed is transferred from the vacuum preliminary chamber to the vacuum processing chamber and a predetermined process is performed.

[0004]

However, in the above-described vacuum processing apparatus, dust (particles) intrudes when the object to be processed is carried in and out of the vacuum preliminary chamber, and when the vacuum preliminary chamber is evacuated or constantly. Even if slow exhaust or slow vent is performed when pressure is restored, dust rises due to the flow of gas. Therefore, in the manufacturing process of semiconductor devices and the like, these dusts adhere to the semiconductor wafer that is the object to be processed and cause defects, which is a major factor in lowering the yield.

An object of the present invention, it is possible to reduce the amount of dust adhered to the workpiece, the improvement of yield is to provide a vacuum processing apparatus that Re FIG <br/>.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 is to maintain a high vacuum in the object to be treated.
An opening is provided in the end wall of the vacuum processing chamber that performs constant processing.
The opening has a valve that opens and closes from the inside of the vacuum processing chamber,
A holder that holds the object to be processed and abuts it so that it can be opened and closed from the outside
Both ends of the opening are closed by and to accommodate the object to be processed.
A vacuum preliminary chamber is formed, and the vacuum preliminary chamber is evacuated.
After opening the valve, open the valve and place the vacuum processing chamber side from the vacuum processing chamber side.
After subjecting the object to be processed to the specified processing, close the valve and
Return the inside of the empty spare chamber to normal pressure so that the holding body can be opened.
In the vacuum processing device,
Dust that adsorbs dust on the surface facing the object to be processed due to static electricity
Open by opening a holder on the outside with a dust adsorption body
The static electricity from the dust adsorbent is removed through the vacuum reserve chamber.
Cleaning means to remove dust that has been
It is characterized by being removed .

[0007]

[0008]

According to a second aspect of the present invention, the cleaning means in the first aspect comprises an ion generating section for generating ions for removing static electricity, and an air blowing section for blowing the generated ions onto the dust adsorbing member. It is characterized by

[0010]

[0011]

SUMMARY OF] According to the present invention, vacuum prechamber dust adsorbent when accommodating the object to be processed in conjunction with a vacuum pre-chamber dust is effectively adsorbed to the vacuum processing chamber to be processed Generation of dust is suppressed by performing a predetermined process in the vacuum preliminary chamber without moving to, and the amount of dust adhering to the object to be processed can be sufficiently reduced, and the yield can be improved. Also,
Clean the dust adsorbent regularly with a cleaning means.
Can be leaned and maintain the adsorption function of the dust adsorbent.
Can have. In addition, the static electricity of the dust adsorption body
Temporarily removed by cleaning means, but dust
Airflow when the vacuum chamber is evacuated or when normal pressure is restored to the adsorbent
The static electricity is charged again due to the friction of and the adsorption function is restored.
It

[0012]

According to the second aspect of the present invention, since the cleaning means includes the ion generating section for generating ions for removing static electricity, and the air blowing section for blowing the generated ions to the dust adsorbing body. The static electricity of the dust adsorbent can be removed, and the adsorbed dust can be effectively removed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an ion implantation apparatus used in a semiconductor device manufacturing process will be described in detail below with reference to the accompanying drawings.

In FIG. 2 showing the overall structure of an ion implantation apparatus which is a vacuum processing apparatus, 1 is an ion source, which is a predetermined gas supplied from a gas bottle housed in the gas box 2, for example, arsine (AsH ₃ ). The dopant gas such as is converted into plasma by the electric power applied from the ion source power source 3. An extraction electrode 4 for extracting plasma ions converted into plasma as an ion beam B is provided in the vicinity of the ion generation source 1. A mass analysis magnet 5 for selecting only desired ions and a variable slit are provided downstream of the extraction electrode 4. 6, an accelerating tube 7 for applying desired energy to the ion beam B, a Y scan plate 8 and an X scan plate 9 for oscillating the ion beam B vertically and horizontally are provided in this order.

Downstream of the X scan plate 9, an injection chamber 10 which is a vacuum processing chamber for ion-implanting a semiconductor wafer (hereinafter also simply referred to as a wafer) W which is an object to be processed (also referred to as a substrate to be processed). Including end station 11
Is provided. The path through which the ion beam B passes and the implantation chamber 10 are maintained in a high vacuum of about 10 ⁻⁶ Torr by a decompression pump such as a turbo molecular pump or a cryopump.

Further, the implantation chamber 10 is provided with a Faraday 12 for detecting the amount of current of the ion beam B and for preventing emitted secondary electrons from escaping. Furthermore,
The implantation chamber 10 is bifurcated and provided with a vacuum preliminary chamber 14 via a valve (also referred to as a track lock valve) 13 on each side. It is configured so that exchange can be performed and throughput can be improved.

The end station 11 will be described in more detail. As shown in FIGS. 1 and 3 to 4, an opening 16 is provided in an end wall (also called a clamping plate) 15 of the injection chamber 10, and this opening 16 is provided. The part 16 is configured to form the vacuum preliminary chamber 14 by closing both ends by the valve 13 and the platen 17 which is a holder for the wafer W. O-rings 18 and 19 as sealing members are provided on the contact surfaces of the valve 13 and the platen 17 with respect to the end wall 15 of the injection chamber, and the opening 16 is always closed by the valve 13 or the platen 17, so that the injection is performed. The inside of the chamber 10 is maintained in a high vacuum state. The injection chamber 10, the valve 13 and the platen 17 are made of, for example, an aluminum alloy.

The valve 13 is provided with a valve opening / closing mechanism 20 for opening / closing the valve 13 and closes the opening 16 from the inside of the injection chamber 10 and opens the opening 16 away from the opening 16 and then moves upward. It is being evacuated to. When the valve 13 is retracted upwards, the tubular movable Faraday 1 that forms a part of the Faraday 12 is interlocked with the valve 13.
2a is moved closer to the opening 16 as shown in FIG. 7 (c).

Particularly, on the surface of the valve 13 facing the wafer W, a dust adsorbing body 21 for adsorbing dust by static electricity is provided. The dust adsorbent 21 is made of a material that is easily charged with static electricity, such as resin or glass, and is formed into a disk shape having an outer diameter substantially the same as that of the wafer.

On the other hand, the platen 17 is provided with an opening / closing mechanism 22 for advancing and retracting the platen 17 from the outside of the injection chamber 10 to open / close the platen 17. In the shaft hole 23 provided in the central portion of the platen 17, a chuck 24 formed of a suction tube that sucks and holds the wafer W by negative pressure is provided so as to be able to move forward and backward (withdraw). The opening 16 is provided with a clamp ring 25 for holding the peripheral edge of the wafer W with the platen 17. The clamp ring 25 is accommodated in an annular groove 26 formed in the opening 16 via a stopper 27, and a coil spring 28 for urging the clamp ring 25 toward the platen is attached to the groove 26.

The platen 17 is provided with an exhaust pipe (not shown) for evacuating (vacuating) the inside of the vacuum preliminary chamber 14, and an inert gas such as nitrogen gas (N ₂ ) in the vacuum preliminary chamber 14. An air supply pipe (vent pipe) 52 for supplying the air and returning to normal pressure is provided. Further, as shown in FIG. 6, the platen 1 is provided above the platen 17.
Cleaning means 29 is provided for removing the static electricity of the dust adsorbing body 21 and removing the adsorbed dust through the vacuum preliminary chamber 14 opened by the retreat of 7.

In this embodiment, the cleaning means 29 has an ion generating portion (also referred to as an ionizer) 30 for generating ions for removing static electricity, and a blower portion 31 for blowing the generated ions toward the dust adsorbing body 21. It is mainly composed of and. The blower unit 31 is composed of a nozzle that blows out an inert gas such as nitrogen gas.

Below the platen 17, as shown in FIG. 3, a plurality (two in the embodiment) of cassettes 32 containing a plurality of (25 in the embodiment) wafers W are placed on a carriage 33. A cassette transport mechanism 35 that reciprocally transports from the cassette loading / unloading port (port) 34 to below the platen 17 is provided. This cassette carrying mechanism 35
A transport path 36 that movably supports the carriage 33 in the transport direction, and a rotation drive unit (motor with reduction gear) 37 at one end.
It is mainly composed of a conveyance drive unit 39 composed of a ball screw 38 having a.

Incidentally, the carriage 3 is provided on the carrying path 36.
3 for detecting the position of the wafer 3 and the wafer W in the cassette 32
An orientation flat matching mechanism for aligning the orientation flat (orientation flat) is provided (not shown). Further, the cassette 32 has a groove for accommodating the wafer W vertically from above at a predetermined interval, and has an open top and bottom (not shown).

Below the platen 17, unprocessed wafers W are supplied to the platen 17 one by one from inside the cassette 32 moved by the carriage 33 as shown in FIGS. Wafer W Platen 1
Wafer transfer mechanism 40 for returning from 7 to cassette 32
Is provided. The wafer transfer mechanism 40 is mainly composed of a pick 41 that vertically supports the wafer W, and a lift drive unit 42 that lifts and lowers the pick 41. The pick 41 has a wide portion 44 at the upper end of a handle 43 having a thin thickness (about 4 mm) which is vertically erected.
In order to support the lower peripheral portion of the wafer W, a support groove 45 having a concave curved surface with a diameter substantially equal to the radius of the wafer W and gradually tapering upward is formed at the upper end of 4. There is.

The elevating and lowering drive section 42 is provided with a pair of guide rods 46 vertically provided below the conveying path 36.
And a rotary frame 47 supported by the guide rods 46 so as to be vertically movable, and a rotary drive unit (motor with reduction gear) 49 for vertically moving the vertical frame 47 via a link 48. The lower end of the pick 41 is attached to the elevating frame 47. The end station 11 is
A processing chamber (also referred to as a transfer chamber or a loader chamber) 50 that communicates with the opening 16 and houses the cassette transfer mechanism 35, the wafer transfer mechanism 40, the platen 17, the cleaning unit 29, and the like is provided. A cassette loading / unloading port 34 is provided at one end of the chamber 50. Also,
Clean air is supplied to the processing chamber 50 from above via a filter 51 and is exhausted from below.

Next, the operation of the above-mentioned ion implantation apparatus or the ion implantation treatment method will be described. First, the valve 13 of the injection chamber 10 is closed, the platen 17 is retracted, and the vacuum preliminary chamber 1
In a state where 4 is opened, the pick 41 of the wafer transfer mechanism 40 moves up to lift the wafer W from the cassette 32 and transfer it to the front of the platen 17. Next, in FIG.
When the chuck 24 moves forward from the platen 17 and sucks the wafer W as shown in FIG.
As shown in (b) of FIG.
Are held by the platen 17.

Next, as shown in FIG. 1, the platen 17 is advanced to close the vacuum preliminary chamber 14, and the wafer W is sandwiched between the platen 17 and the clamp ring 25. Then, the vacuum of the chuck 24 is cut off, and the vacuum preliminary is completed. The inside of the chamber 14 is evacuated by a vacuum pump such as a rotary pump. Next, the valve 13 is opened to open the preliminary vacuum chamber 14 to the injection chamber 10 side,
When the valve 13 is retracted upward, it is interlocked with this and
The movable Faraday 12a has the opening 1 as shown in FIG.
6 is moved closer to 6 to cover the outer circumference of the path of the ion beam B.

Next, the target wafer W is irradiated with the ion beam B to carry out an ion implantation process, and when this process is completed, the valve 13 is closed and the inside of the vacuum preliminary chamber 14 is returned to the normal pressure by supplying nitrogen gas. Then, the vacuum of the chuck 24 is generated to open the platen 17. After that, the wafer W is returned from the platen 17 to the cassette 32 in the reverse order of the above. Then, the ion implantation process of the wafer W is sequentially and sequentially performed in the above-described cycle.

In such an ion implantation process, as shown in FIG.
As shown in FIG. 5, when the platen 17 is closed and the wafer W is stored in the vacuum preliminary chamber 14, the dust in the vacuum preliminary chamber 14 is adsorbed to the dust adsorbing body 21 provided in the valve 13 by its electrostatic adsorption action. . Since the dust adsorbing body 21 is provided on the valve 13 so as to face the wafer W, the dust floating around the wafer W can be effectively adsorbed to the dust adsorbing body 21 and the dust adhering to the wafer W. Can be reduced and the yield can be improved.

When the dust adsorbent 21 adsorbs dust to some extent, the dust adsorbent 21 is electrostatically saturated and the adsorbability is lowered, and the dust adsorbed up to that time may be released. Therefore, the dust adsorbent 21 is regularly cleaned by the cleaning means 29. As shown in FIG. 6, the cleaning means 29 is composed of an ion generating section 30 provided above the platen 17 and an air blowing section 31 for blowing the generated ions together with nitrogen gas onto the dust adsorbing body 21. The ions adsorbed on the surface of the dust adsorbent 21 can be removed by periodically spraying ions together with nitrogen gas onto the dust adsorbent 21 with the platen 17 open. The removed dust is discharged to the outside from an exhaust port (not shown) below the processing chamber 50.

As a result, the suction function of the dust suction body 21 can be maintained, and the adhesion of dust to the wafer W can be prevented. The static electricity of the dust adsorbing body 21 is temporarily removed by the ions of the cleaning means 29. However, the dust adsorbing body 21 is again removed by the friction of the air flow when the vacuum preliminary chamber 14 is evacuated or when the normal pressure is restored. The static electricity is charged and the adsorption function is restored.

As described above, according to the ion implantation apparatus or the ion implantation treatment method, the implantation chamber 10 which is a vacuum treatment chamber.
When the wafer W is accommodated in the vacuum preliminary chamber 14 provided (continuously provided) via the valve 13 in the above, dust in the vacuum preliminary chamber 14 is provided in the valve 13 so as to face the wafer W. It is adsorbed by the dust adsorbent 21. Then, the valve 13 is opened and the wafer W in the vacuum preliminary chamber 14 is subjected to the ion implantation process from the implantation chamber 10 side. Therefore, the dust in the vacuum preparatory chamber 14 can be effectively adsorbed by the dust adsorbing body 21 facing the wafer W, and the wafer W is introduced into the injection chamber 10.
Since it is possible to suppress the generation of dust by performing the ion implantation process in the vacuum preliminary chamber 14 without moving to, the amount of dust adhering to the wafer W can be sufficiently reduced.
Yield can be improved.

Further, the vacuum preliminary chamber 14 is provided with the wafer W.
A cleaning means 29 for removing the static electricity of the dust adsorbing body 21 and removing the adsorbed dust through the vacuum preparatory chamber 14 opened to the outside is constituted by the platen 17 holding the. Because it is provided,
By this cleaning means 29, the dust adsorbent 21
Can be cleaned regularly, and the dust adsorbent 2
The adsorption function of 1 can be maintained. Further, since the cleaning means 29 is composed of an ion generating section 30 for generating ions for removing static electricity and a blower section 31 for blowing the generated ions to the dust adsorbing body 21, the dust adsorbing body 21 is It is possible to remove static electricity and effectively remove the adsorbed dust.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the gist of the present invention. For example, the dust adsorbent of the above embodiment is designed to be charged with static electricity due to the friction of the air flow when the vacuum preliminary chamber is evacuated or when the normal pressure is restored, but it is positively applied by applying a voltage of several KV. You may comprise so that it may be electrically charged. Further, in the above embodiment, the case where the present invention is applied to the ion implantation apparatus has been described, but the present invention is a vacuum processing apparatus that performs a predetermined process on a target object under a reduced pressure atmosphere, in addition to the ion implantation apparatus, For example, it can be applied to an etching apparatus, an ashing apparatus, a sputtering apparatus, a low pressure CVD apparatus and the like. Further, the object to be processed can be applied to not only a semiconductor wafer but also an LCD substrate or the like.

[0037]

In summary, according to the present invention, the following excellent effects can be obtained.

[0038] (1) According to the present invention, upon receiving the object to be processed in the vacuum prechamber, with a vacuum pre-chamber dust is effectively adsorbed by the dusts adsorbent, the treated By performing a predetermined process in the vacuum preparatory chamber without transferring the body to the vacuum processing chamber, the generation of dust is suppressed, the amount of dust adhering to the object to be processed can be sufficiently reduced, and the yield can be improved. In addition, the dust adsorbent is cleaned by the cleaning means.
Can be cleaned regularly,
The adsorption function can be maintained.

(2) According to the invention of claim 2 , the above-mentioned clear
The burning means generate ions to remove static electricity.
And the generated ion to the dust adsorbent.
Since it consists of a blower unit that blows, it absorbs the dust
Removes static electricity from the body and effectively removes adsorbed dust
You can

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing an embodiment in which the present invention is applied to an ion implantation device.

FIG. 2 is a plan view showing the overall configuration of an ion implantation device.

FIG. 3 is a side sectional view showing a configuration of an end station of the ion implantation apparatus.

FIG. 4 is a perspective view showing a part of an end station.

FIG. 5 is a front view showing a wafer transfer mechanism.

FIG. 6 is a cross-sectional view showing a state in which the dust adsorbent is being cleaned.

FIG. 7 is an explanatory diagram schematically showing steps up to setting a wafer in a vacuum preliminary chamber and performing an ion implantation process.

[Explanation of symbols]

W Semiconductor wafer (Processing object) 10 Injection chamber (vacuum processing chamber) 13 valves 14 Vacuum spare room 17 Platen (holding body) 21 Dust adsorbent 29 Cleaning means 30 Ion generator 31 air blower

Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01L 21/205 H01L 21/205 21/3065 21/68 A 21/68 21/302 N (56) Reference JP-A-6-140294 (JP , A) JP-A-5-20683 (JP, A) JP-A-4-61227 (JP, A) Actual flat 6-54763 (JP, U) Actual flat 3-22528 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 14/56 B01J 3/00 H01J 37/18 H01J 37/317 H01L 21/203 H01L 21/205 H01L 21/3065 H01L 21/68

Claims (2)

(57) [Claims] 1. An object to be processed is subjected to a predetermined treatment while being maintained in a high vacuum.
There is an opening in the end wall of the vacuum processing chamber for
Is a valve that opens and closes from inside the vacuum processing chamber, and the
A holding body that holds the body and abuts it so that it can be opened and closed from the outside.
Both ends of the opening are closed and the vacuum
After forming a storage room, after evacuating the vacuum spare room
Open the above valve and process from the vacuum processing chamber side
Apply predetermined treatment to the body, and after the treatment, close the valve above and reserve the vacuum.
Vacuum to return the inside of the room to normal pressure and open the holder
In the processing apparatus, the valve to be processed in the vacuum processing chamber
Dust adsorption that electrostatically adsorbs dust on the surface facing the body
It was opened by opening the holder on the outside of the body
Remove the static electricity of the dust adsorbent through the vacuum reserve chamber,
Cleaning means is provided to remove the adsorbed dust.
The vacuum processing device is characterized in that 2. The cleaning means removes static electricity
Ion generator that generates ions for
It consists of a blower unit that blows ions onto the dust adsorbent.
The vacuum processing apparatus according to claim 1, wherein the this.