JPH07130674A - Vacuum processing method and apparatus therefor - Google Patents

Abstract

PURPOSE:To remove impurities and reaction products deposited in a trap without interrupting heat treatment by providing a portable recovery part connected with fixed trap means such that it includes trap means and exhaust means, and recoverying reaction products or reaction gas in the fixed trap means. CONSTITUTION:A recovery passage 40 is one for use in recovering reaction products and impurities captured by trap means 16, and at the end thereof a connector 42 capable of being coupled with a recovery part 44. A recovery part body 48 connected to an exhaust pump 46 is provided on a movable truck 44A disposed in the recovery part. The recovery part body 48 includes a recovery pipe 52 including a valve 50 interposed in the course thereof, and the recovery pipe 52 is connected with the connector 42 of the recovery passage 40. The recovery part body 48 is constructed with a CVD trap mechanism with larger capacity than the trap means 16. Hereby, there is eliminated the need of eliminating the removal of the trap means from an exhaust passage of a heat treatment apparatus upon maintenance of the trap means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for reducing pressure, and more particularly to a method and apparatus for reducing pressure in a heat treatment apparatus used for diffusion, oxidation, annealing, film formation and the like.

[0002]

2. Description of the Related Art As is well known, in a heat treatment apparatus, which is one of the depressurization processing apparatuses, a heat treatment such as diffusion, oxidation, annealing or film formation is performed on a semiconductor wafer or the like after setting the inside of the heat treatment section in a vacuum atmosphere. It is performed on the processing body. The setting of such a vacuum atmosphere is a treatment for preventing impurities such as oxygen and water in the atmosphere from adhering to the object to be processed. For this reason, an exhaust pump is provided in the exhaust system of the heat treatment unit, and a trap is arranged in the exhaust path connected between the exhaust pump and the heat treatment unit.
In this trap, the impurities and reaction products from the heat treatment section are collected by adhering them to prevent the impurities and reaction products from being taken into the exhaust pump from the heat treatment section. .

An example of such an exhaust system structure is shown in FIG.

In FIG. 6, the exhaust system is provided with an exhaust passage 14 connected between the heat treatment unit 10 and an exhaust pump 12, and an exhaust passage formed by the exhaust passage 14 is provided with an exhaust passage from the heat treatment unit 10. The trap means 16, the main valve 18, and the exhaust pump 12 are arranged along the exhaust direction. In such a structure, when the exhaust stroke is set, the exhaust pump 12 operates and the main valve 18 is opened to evacuate the inside of the heat treatment section 10.
Impurities and reaction products are collected by the trap means 16.

By the way, the above-mentioned exhaust system is provided with a structure for eliminating a problem when the main valve 18 is opened in an instant. That is, when the main valve 18 is opened instantaneously during evacuation, the pressure inside the heat treatment section 10 suddenly changes. For this reason, there is a possibility that the object to be processed arranged in the heat treatment section may move or particles may be wound up inside.

Therefore, a bypass passage 22 that bypasses the main valve 18 is provided in the exhaust passage, and this bypass passage 22 opens and closes the bypass passage 22.
4 are arranged. The bypass passage 22 is set to have a flow passage area that allows a smaller amount of gas to flow than the exhaust passage 14 opened and closed by the main valve 18, for example. The structure provided with such a bypass passage 22 allows a small amount of gas to flow through the bypass passage 22,
It is used for slow exhaust in which the exhaust from the heat treatment unit 10 is gradually performed at the initial stage of exhaust.

Therefore, in the bypass passage 22, the sub-valve 24 is opened before the main valve 18 at the time when the exhaust stroke is set, so that the exhaust from the heat treatment section 10 is gradually performed, so that the bypass passage 22 is set in the heat treatment section. It is designed to prevent sudden pressure fluctuations. The sub valve 24
Is to prevent a transient pressure change that occurs in the heat treatment section 10 at the beginning of the exhaust stroke setting, so that when the exhaust progresses and the movement of the object to be processed and the winding of particles do not occur. Main exhaust is performed in cooperation with the opening of the main valve 18 either closed or not closed. Then, the main valve 18 and the sub valve 24
Is opened during the processing in the heat treatment section 10 and closed at the time of switching to normal pressure during loading / unloading. Therefore, the heat treatment section 10 is evacuated while the treatment is being performed, whereby the products and gases from the heat treatment section 10 are introduced toward the trap means 16. The main valve 1
Some of the eight are equipped with a heating means, for example, and in this structure, the product is prevented from adhering to the valve itself.

[0008]

By the way, in the above-mentioned depressurization processing apparatus, it is necessary to maintain a trap for collecting impurities and reaction products from the heat treatment section.
That is, the exhaust conductance of this trap decreases when the amount of impurities or reaction products deposited from the heat treatment section increases. Therefore, it is necessary to remove the impurities and reaction products collected so far. Therefore, conventionally, the traps arranged in the exhaust path are removed from the exhaust path, and then the impurities and reaction products deposited are removed.

However, when removing the trap from the exhaust path, the heat treatment process must be interrupted. Therefore, the throughput in the manufacturing process of the object to be processed such as semiconductor may be deteriorated.

Therefore, it is conceivable to increase the size of the trap itself in order to increase the amount of impurities and reaction products collected from the heat treatment section and prolong the cycle requiring maintenance. However, it cannot be denied that such a method would make the structure of the heat treatment apparatus large.

Therefore, an object of the present invention is to provide the above-mentioned conventional heat treatment apparatus, in particular, a method and structure capable of removing impurities and reaction products accumulated in the trap without interrupting the heat treatment process. Another object of the present invention is to provide a reduced pressure treatment method and an apparatus using the same.

[0012]

In order to achieve this object, the invention according to claim 1 supplies a reaction gas to a treatment section heated under a reduced pressure atmosphere, and a reaction gas and a reaction which are in contact with an object to be treated. A depressurization processing apparatus that discharges a product by exhaust means through fixed trap means provided in an exhaust path, comprising a portable recovery unit that is connected so as to be able to communicate with the fixed trap means. The section has a trap means and an exhaust means, and is characterized in that the reaction product or reaction gas in the fixed trap section is recovered.

According to a second aspect of the present invention, in the first aspect, either or both of the fixed trap and the recovery section have a structure provided with a counter electrode and capable of performing both CVD and etching processes. It has a feature.

According to a third aspect of the present invention, a fixed trap for supplying a reaction gas to a treatment section heated under a reduced pressure atmosphere to trap the reaction gas and a reaction product in contact with the object to be treated, and the fixed trap. A mobile trap that can communicate
An exhaust passage connected between the exhaust side of the processing unit and the exhaust means, a main valve arranged in the exhaust passage for opening and closing the exhaust passage, and one end connected to the exhaust passage leading to the fixed trap. And an exhaust pipe provided with an exhaust port through a valve at the other end thereof.The fixed trap deposits reaction products and impurities by a CVD process, while impurities and reactions deposited by an etching process. It is characterized in that the product is removed and discharged toward the moving trap through the exhaust pipe.

According to a fourth aspect of the present invention, in the third aspect, the operation of discharging the impurities or the reaction products from the fixed trap to the moving trap is performed when the object to be processed is carried in and out of the processing section. I am trying.

[0016]

According to the present invention, impurities and reaction products can be removed without removing the trap provided in the exhaust path from the path. That is, the trap is connected to the recovery unit in the exhaust path. Therefore, impurities and reaction products accumulated in the trap can be recovered and removed by the recovery unit. In addition, the trap can deposit impurities and reaction products by the CVD process and remove impurities and reaction products deposited by the etching process, so that the deposits can be efficiently removed and recovered.

Further, according to the present invention, the trap means attached to the heat treatment apparatus is provided with a recovery section for recovering the reaction products and impurities accumulated in the trap means separately from the trap means. It is possible to regenerate the trap means in which the reaction products and impurities are deposited without increasing the size so much. Moreover, since the time for collecting the impurities and the reaction products from the trap by the collecting unit is when the object to be processed is carried in and out of the processing unit, a special period for removing the impurities and the reaction products from the trap is provided. No need to set. Therefore, for example, since the trap regeneration period in the semiconductor manufacturing process is not set again, the throughput does not decrease.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 1 is a piping diagram corresponding to FIG. 6 schematically showing an exhaust structure used in a heat treatment apparatus which is an example of a decompression processing apparatus according to an embodiment of the present invention. In addition, in FIG.
The same components as those shown in FIG. 6 are designated by the same reference numerals.

In FIG. 1, an exhaust passage 14 is connected to the exhaust side of the heat treatment section 10 between it and the exhaust pump 12.

A trap means 16 and a main valve 18 are arranged in the exhaust passage 14 along the direction of gas flow from the heat treatment section 10 to the exhaust pump 12 (the direction of the arrow in the figure). A butterfly valve 20 is provided in front of the trap means 16.

The butterfly valve 20 is an exhaust conductance means for improving the negative pressure on the trap means 16 side by opening and closing the exhaust passage 14. For this reason, the butterfly valve 20 is normally open, and is closed after the depressurized heat treatment section returns to normal pressure.

Further, at a position straddling the main valve 18, bypass passages 22 each having an end connected to the exhaust passage 14 are provided as in the structure shown in FIG. In the middle of this, bypass road 2
A sub-valve 24 for opening and closing 2 is arranged.

On the other hand, the trap means 16 in this embodiment
Has a structure capable of performing a CVD process capable of depositing reaction products and impurities by generating plasma.

Therefore, inside the trap means 16,
As an example, a CVD structure provided with a counter electrode is provided. As shown in FIG. 2, the electrode plate 26 has a plurality of ring-shaped discs arranged in parallel in the horizontal direction along the vertical direction of the trap means 16. I am allowed. Therefore, the reaction gas discharged from the processing section can pass between the electrodes and flow upward from the openings of the electrodes, as shown in FIG. A cleaning gas supply pipe (not shown) is connected to the downstream side in the flow direction of the reaction gas that has passed through the heat treatment section 10.

Of the plurality of electrode plates 26, odd-numbered electrode plates 26A are, for example, as shown in FIG. 2, a small diameter hole 28 on one side and a large diameter hole on the other side on a line divided by a semicircle. 30 are formed respectively, and conversely, the even-numbered electrode plates 26 are formed.
As shown in FIG. 2, B has a small diameter hole 28 on the other side and a large diameter hole 30 on the one side. Such an electrode plate 26 is used as electrode plates which are opposite to each other when turned upside down.
If only the types are prepared and they are turned inside out, they can be used in any case.

As the arrangement of the electrode plates 26, the electrode plates 26A in the odd-numbered usage patterns and the electrode plates 26B in the even-numbered usage patterns are alternately arranged, and only the small-diameter holes 28 are arranged. First and second electrode rods 32 and 34 having outer diameters that come into contact with each other are inserted through the electrode plates as shown in FIG. In the case of this embodiment, one electrode rod is connected to the RF power source 54 side, and the other electrode rod is connected to the ground side.

The first and second electrode rods 32 and 34 are shown, for example, in FIGS. 4 and 5 in order to surely prevent contact with the large diameter hole 30 of each electrode plate and insulate them. like,
Separator 36 formed of an insulating member such as ceramics
Is used.

The separator 36 is formed in a hollow cylindrical shape, the outer diameter of which is such that it can be inserted into the large-diameter hole 30, and the inner diameter thereof is the first and second electrode rods 32, 34. Can be inserted.

The separator 36 is shown in FIG.
In FIG. 4 showing an enlarged view of a portion indicated by reference numeral A, for example, in order to ensure insulation between the odd-numbered two electrode plates 26A and the electrode plates 26B located between them, the electrode rod 3
2 and is inserted into the large diameter hole 30 of the electrode plate 26B. As a result, direct contact between the odd-numbered electrode plates 26A and the even-numbered electrode plates 26B via the electrode rods is prevented, and the distance between the electrode plates 26A is set to a predetermined dimension. By continuously inserting such a separator 36 along the longitudinal direction of the electrode rods 32 and 34, the parallel pitch between the electrode plates 26A and 26B can be maintained at equal intervals. Similarly, the separators 36 are arranged between the even-numbered electrode plates 26B through the large-diameter holes 30 of the odd-numbered electrode plates 26A. In FIG. 4, reference numeral 38 indicates a conductive layer such as aluminum coated on the inner peripheral surface and the end surface of the separator 36.
The conductive layer 38 not only forms a conductive path only by contact between the electrode rods 32 and 34 and the small-diameter holes of the electrode plate 26, but also between the end surface of the separator 36 and the upper and lower surfaces of the electrode plate 26 facing this. It is provided to allow contact and to secure a conductive path.

On the other hand, in FIG. 1, the butterfly valve 2
At the position behind 0 and in front of the trap means 16, the valve 3
The recovery passage 40 with 8 interposed is connected. The recovery passage 40 is a passage used when the reaction products and impurities collected by the trap means 16 are recovered, and a connector 42 that can be connected to a recovery unit described later is provided at an end portion thereof. .

The recovery unit 44 is one of the features of this embodiment, and includes a movable chassis 44A, and the recovery unit main body 48 connected to the exhaust pump 46 is provided on the chassis 44A. The recovery unit main body 48 includes a recovery pipe 52 with a valve 50 interposed, and the recovery pipe 52 is the recovery passage 4
0 connector 42. The recovery unit main body 48 has the trap means 16 described above.
It is composed of a CVD trap mechanism having a larger capacity. That is, even in the recovery unit main body 48,
Plasma CVD having the same structure as the above-mentioned trap means 16
Equipped with equipment. Therefore, in this embodiment, an RF power source 54 is provided to the trap means 16 and the recovery unit main body 48, and the distributor 5 is provided for this RF power source.
6, the electric power is distributed and supplied. Further, the exhaust pump 46 is provided with a pipe 58, and the pipe 58 is connected to an exhaust gas treatment device 62 via a connector 60.

Next, the operation will be described.

The heat treatment section 10 is evacuated by the exhaust pump 12 and supplied with a reaction gas after the internal temperature is set to 300 to 400 degrees by the heaters located in the surroundings. The film forming process is performed on the object to be processed.

On the other hand, the unreacted gas supplied into the heat treatment section and the products and impurities produced by the reaction are introduced from the heat treatment section 10 into the trap means 16. In the trap means 16, the RF power source 54 supplies power to one of the electrode rods to form a plasma of a reaction gas and form a reaction product or an impurity on the electrode plate 26. Therefore, when the reaction products and impurities discharged from the heat treatment unit 10 are accumulated on the electrode plate in the trap means 16, as shown in FIG. 5, the reaction products block the gap between the electrode plates. However, as shown by the arrow in the figure, the trap means 16
Since the exhaust gas that has flowed in passes through the gaps between the electrode plates which are not blocked, the reaction product impurities are finally deposited on the entire electrode plates.

Therefore, when the reaction products and impurities deposited inside the trap means 16 are removed, the recovery section 44 is used.
The recovery pipe 52 in the connector 42 of the recovery passage 40.
Connect to. In the collection unit 44 that communicates with the collection passage 40,
The exhaust pump 46 is driven and the recovery unit main body 48
Preparations are made for the plasma CVD process in. Then, in the trapping means 16, plasma etching is performed by supplying a cleaning gas and supplying electric power to the electrode rod, so that the deposited reaction products and impurities are removed. Such a process is performed during the load / unload process in the heat treatment unit 10 so that the deposit removal process period does not overlap with the other process execution period and the throughput in the manufacturing process is not deteriorated. Preferably.

When the reaction products and impurities deposited by plasma etching in the trap means 16 are to be removed, the reaction part floating in the trap means 16 can be obtained by simply providing the recovery part 44 with an exhaust structure. The products and impurities may be removed by suction.

Further, the trap means 16 has a volume capable of accommodating one day's worth of reaction products and impurities, while the recovery section 44 has a larger volume. The recovery rate of the recovery unit 44 can be improved.

As described above, according to this embodiment, in the trap means, in order to collect reaction products and impurities, C
It is possible to perform the VD process and also the plasma etching by using the electrode plate used for this process. Therefore, in addition to the original trapping operation of the trap means, the self-cleaning operation can also be used, so that no special structure is required for removing the deposited reaction products and impurities.

Further, since the recovery unit is portable, it can be reused among the respective heat treatment apparatuses, whereby it is not necessary to provide a recovery member for each heat treatment apparatus.

The present invention is not limited to the above embodiment, and the number of trap means is not limited to one, for example. That is, the trap means 16 is arranged in parallel with the exhaust passage 14, and the trap means 1
The flow direction of the exhaust gas with respect to 6 may be switched by a direction switching valve. By doing so, by alternately using the trapping means, it is not necessary to interrupt the trapping work, and continuous heat treatment becomes possible.

Further, in addition to the removal of the reaction products deposited on the trap means 16, the removal of the deposits on the recovery unit main body 44 may be carried out at the same time.

Further, although the case where the butterfly valve 20 is provided has been described as the structure for vacuum evacuation in the above embodiment, it is also possible to perform vacuum evacuation without using this valve. That is, in FIG. 1, the trapping means 16 may be evacuated by closing the opening / closing caps or the automatic shutters indicated by reference numerals 64 and 66 to form a closed space in the evacuating system. In such a structure, for example, the automatic shutter 66 is provided after unloading the board on which the objects to be processed are loaded.
(The auto shutter in this case is preferably one with an O-ring) to make the inside of the heat treatment section a closed space and evacuate in that state. In such a scheme, for example,
When gas is released by baking, or
When a hygroscopic product such as TEOS is discharged toward the trap means 16, it is effective in preventing moisture from entering the atmosphere.

[0044]

As described above, in the present invention, it is not necessary to remove the trap means from the exhaust path of the heat treatment apparatus when performing maintenance of the trap means. Therefore, in particular, if the step of removing the reaction products and impurities accumulated in the trap means is performed at the time of loading / unloading in the heat treatment apparatus, the heat treatment step is not interrupted.

Further, according to the present invention, since the reaction product and impurities accumulated in the trap means can be recovered by the recovery member, the trap means can be regenerated by regenerating it without increasing the volume of the trap means. Can be used for any purpose. Moreover, by performing such a regeneration process of the trap means at a time when the heat treatment is not performed, such as when loading / unloading the heat treatment apparatus, it is not necessary to newly set the regeneration process of the trap means, and the manufacturing process can be performed. It does not need to reduce the throughput in the process.

[Brief description of drawings]

FIG. 1 is a piping diagram schematically showing a main part of a depressurization processing apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing components of trap means used in the depressurization processing apparatus shown in FIG.

FIG. 3 is a cross-sectional view showing the inside of trap means used in the decompression processing apparatus shown in FIG.

FIG. 4 is an enlarged cross-sectional view of a portion indicated by reference sign A in FIG.

FIG. 5 is a schematic diagram for explaining the operation of the trap means shown in FIG.

FIG. 6 is a schematic diagram showing a conventional example of a decompression processing apparatus.

[Explanation of symbols]

 10 Heat treatment apparatus which is one of depressurization processing apparatus 12 Exhaust pump forming exhaust means 14 Exhaust passage 16 Trap means 26 Electrode plate 44 Collection section

Claims (4)

[Claims] 1. An exhaust means for supplying a reaction gas to a processing part heated under a reduced pressure atmosphere, and a reaction gas and a reaction product which come into contact with an object to be processed through a fixed trap means provided in an exhaust path. In the depressurization processing apparatus for discharging by means of the above, there is provided a portable recovery part connected to the fixed trap means so that the fixed trap means can communicate with the fixed trap means. A reduced-pressure treatment method comprising recovering a product or a reaction gas. 2. The reduced pressure processing method according to claim 1, wherein one or both of the fixed trap and the recovery unit has a structure having a counter electrode and capable of performing both CVD and etching. . 3. A fixed trap for supplying a reaction gas to a treatment section heated under a reduced pressure atmosphere to trap the reaction gas and a reaction product in contact with an object to be treated, and a movable trap communicable with the fixed trap. , An exhaust passage connected between the exhaust side of the processing section and the exhaust means, a main valve arranged in the exhaust passage to open and close the exhaust passage, and one end in the exhaust passage leading to the fixed trap. Connected,
An exhaust pipe provided with an exhaust port through a valve at the other end, and the fixed trap deposits reaction products and impurities by a CVD process, and impurities and reaction products deposited by an etching process. Is removed and discharged toward the moving trap through the exhaust pipe. 4. The decompression processing apparatus according to claim 3, wherein the operation of discharging the impurities or the reaction products from the fixed trap to the moving trap is performed when the object to be processed is carried in and out of the processing unit.