JPH062950B2 - Gas phase reactor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gas phase reactor. More specifically, the present invention relates to a first preliminary chamber containing a loader section, a second preliminary chamber containing an unloader section, a first wafer transfer mechanism for supplying a wafer to a loader section in the first preliminary chamber, and a second wafer transfer mechanism. The present invention relates to a vapor phase reactor for performing a plasma CVD process or a plasma etching process in which a second wafer transfer mechanism that receives a wafer from an unloader section in a preliminary chamber and a reaction chamber are arranged in a rectangular shape.

[Prior Art] One of the methods that are widely used in the semiconductor industry as a method for forming a thin film is vapor phase epitaxy (CVD: C).
chemical Vapor Deposition
n). CVD means that a gaseous substance is made into a solid substance by a chemical reaction and deposited on distillation.

The characteristics of CVD are that various thin films can be obtained at a deposition temperature well below the melting point of the thin film to be grown, and
Since the grown thin film has a high purity and has stable electrical characteristics even when grown on Si or a thermal oxide film on Si, it is widely used as a passivation film on a semiconductor surface.

The CVD methods are roughly classified into three types: (1) normal pressure, (2) reduced pressure, and (3) plasma.

Due to the rapid progress of VLSI technology in recent years,
The word "I" also began to be heard. Along with this, Si devices became more highly integrated and faster, and 6 inch to 8 inch, and further 12 inch large diameter substrates were used. .

With the progress of high integration of semiconductor devices, high-quality and high-precision insulating films have been required, and it has become difficult to cope with them by the atmospheric pressure CVD method. Therefore, the plasma CVD method using plasma chemistry has been receiving attention.

In plasma CVD, a compound gas (eg, SiH ₄ and N ₂ O) containing constituent atoms of a generated film (eg, SiOx film) is brought into a plasma state, and chemically active ions or radicals (chemically active neutral atoms or It is a method of growing a thin film at a low temperature (for example, about 300 ° C.) by decomposing it into molecular species.

In the conventional CVD method, the decomposition and reaction of gas molecules are performed purely and thermally at a high substrate temperature, whereas the plasma CVD method is characterized in that the substrate temperature is kept low by the aid of electric energy by electric discharge. .

This method has the advantages of good step coverage (surrounding or pattern step coverage), strong film strength, and excellent moisture resistance. In addition, the film formation rate (deposit rate) of the plasma CVD method is extremely higher than that of the low pressure CVD method.

[Problems to be Solved by the Invention] The plasma CVD method is carried out under a vacuum condition of about 1-0.4 Torr. Therefore, the wafer loading and unloading operations must be performed by the loader section and the unloader section housed in the preliminary chamber separated from the reaction chamber by the gate valve. That is, the pressure in the reaction chamber is made equal to the pressure in the loader section or the unloader section, and then the gate valve is opened to load or unload the wafer. When the loader section and the unloader section are housed in the spare chamber, there is also an advantage that foreign matter can be prevented from adhering to the wafer.

The method conventionally adopted as the method of arranging the loader section and the unloader section in the reaction chamber is, for example,
There is a method in which one wafer carrier arm also serves as the unloader section. In this case, since only one spare room is required, the device becomes compact and the space saving effect is great.
However, the throughput is significantly reduced.

As another arrangement method, there is a method of arranging the first preliminary chamber containing the loader section and the second preliminary chamber containing the unloader section in parallel and connecting them to the reaction chamber. This method can be applied only to a large reaction chamber having a size capable of arranging two auxiliary chambers in parallel. Attempts have been made to make the reaction chamber rectangular and to connect the first and second auxiliary chambers in parallel. However, in the rectangular reaction chamber, internal conditions such as the flow pattern and glow discharge of the reaction gas fed in the furnace become non-uniform,
The film quality deteriorates. As a result, the yield of products also decreases.

In another arrangement method, the first spare chamber containing the loader section and the second reserve chamber containing the unloader section are sandwiched between the reaction chambers.
It is a method of arranging in a relation of °. In this case, the entire device becomes vertically long, and space is wasted. Therefore, it is not necessarily an appropriate arrangement in terms of the basis efficiency of the device design. Furthermore, the space for arranging the device is limited in the semiconductor manufacturing factory. That is, the line configuration is dimensionally determined. Even if the wafer size is increased from 6 inches to 12 inches, the total length of the line cannot be arbitrarily extended in accordance with the increase in the diameter of the wafer.

As another aspect of arranging the reaction chamber, the first preliminary chamber, and the second preliminary chamber at 180 °, an attempt has been made to make the reaction chamber and / or the preliminary chamber multiple. This aims at improving the throughput by sharing the reaction chamber and / or the spare chamber.

If multiple reaction chambers are used, it is possible to distinguish between those during film formation reaction and those during film formation preparation (for example, wafer loading / unloading), and wasteful waiting time is saved to improve throughput. It is an attempt to improve. However, in this case, when trouble occurs in one device in the group,
The impact will be global and the entire herd will have to be shut down. As a result, the throughput cannot be improved as expected.

Further, conventionally, a cassette for stocking wafers is housed in the spare chamber, and the wafers are directly delivered to the loader unit or the unloader unit in the spare chamber. In this case, in addition to the drawback that a large amount of wafers cannot be stocked, there is the drawback that the cassette cannot be replaced unless the pressure in the preliminary chamber is equal to atmospheric pressure.

Particularly in the case of the single-wafer type, since it is necessary to carry the wafers into and out of the reaction chamber one by one, it is not preferable to accommodate the cassettes in the preliminary chamber because the film forming operation is interrupted due to the exchange of the cassettes.

As another problem, it is necessary to consider the space for arranging peripheral devices such as an exhaust system and / or a drive system for driving the CVD thin film forming apparatus. In the conventional CVD thin film forming apparatus, these peripheral devices were simply arranged on the side of the main body, but only that portion was projected, and a large amount of wasted space was created.

Only the reactive gas used is different between the plasma CVD method and the plasma etching method.
Or the structure is basically the same.

[Object of the Invention] Accordingly, an object of the present invention is to perform a film forming operation continuously from the loading to the unloading of wafers without interruption, and in addition, there is no waste in space, and the device design is compact and highly efficient. A gas phase reactor is provided.

[Means for Solving Problems] As means for solving this problem, the present invention is
In a vapor phase reaction apparatus having a loader section for loading a wafer into a reaction chamber and an unloader section for unloading a wafer from the reaction chamber, a first preliminary chamber accommodating the loader section, a second accommodating the unloader section A gas phase reaction apparatus in which a preliminary chamber, a first wafer transfer mechanism for supplying a wafer to the loader section, a second wafer transfer mechanism for receiving a wafer from the unloader section, and a reaction chamber are arranged in a rectangular shape. I will provide a.

[Operation] As described above, in the gas phase reaction apparatus of the present invention, the first preliminary chamber, the second preliminary chamber, the first wafer transfer mechanism, the second wafer transfer mechanism, and the reaction chamber are arranged in a rectangular shape as a whole.

Therefore, various peripheral devices for the exhaust system and the drive system can be accommodated in this rectangular internal space. as a result,
The entire gas-phase reactor is grouped into a square shape, resulting in an extremely compact device with high basis efficiency.

Further, since the wafer transfer mechanism is arranged outside the preparatory chamber, the cassette can be exchanged very easily, and the wafer can be continuously and automatically operated without any interruption from loading to unloading.

[Embodiment] An embodiment of the present invention will be described in more detail below with reference to the drawings.

FIG. 1 is a schematic perspective view showing one embodiment of the gas phase reaction apparatus of the present invention.

As shown in FIG. 1, the gas phase reactor of the present invention is arranged in an L-shape so that the first preliminary chamber 12 and the second preliminary chamber 14 are substantially orthogonal to the reaction chamber 10. Further, a first wafer transfer mechanism 25 is arranged near the end of the first preliminary chamber 1 so as to be substantially orthogonal to the first preliminary chamber 12,
A second wafer transfer mechanism 62 is arranged near the end of the second preliminary chamber 14 so as to be substantially orthogonal to the second preliminary chamber 14. In this way, the entire device constitutes a rectangular array.

In the rectangular central space 100, peripheral support devices such as an exhaust system and / or a drive system can be arranged. Thus, the entire device can be formed into a rectangular shape, and the space is used very effectively, so that there is almost no wasted space.

The twelfth preliminary chamber 12 and the second preliminary chamber 14 are connected to the reaction chamber 10 via respective gate valves (not shown).

The reaction chamber 10 has a symmetrical shape with a square cross section. In the symmetrical reaction chamber, the flow pattern of the reaction gas fed into the chamber becomes uniform, and good film formation results can be obtained. The symmetrical shape may be circular. In the case of plasma CVD or plasma etching, if the reaction chamber is symmetrical, the discharge will be stable and better results will be obtained.

A wafer mounting table 16 is arranged inside the reaction chamber.
Although not shown, a heater is provided on the wafer mounting table and heats the wafer mounted on the mounting table to a temperature necessary for the plasma film forming reaction.

Around the wafer mounting table, a wafer receiving claw 18 for lifting a wafer placed on the mounting table is arranged. The wafer receiving claw is configured to be replaceable according to the diameter of the wafer used. Therefore, a long wafer catch is used for a 6 inch wafer and a short catch is used for a 12 inch wafer.

A shutter ring 20 is arranged on the outer periphery of the wafer mounting table in order to define a reaction space around the wafer mounting table in a circular shape.
With this shutter ring, the cross section of the reaction space can be made into a circular symmetrical shape, and not only the flow pattern of the reaction gas to the wafer on the wafer mounting table becomes more uniform, but also the density of plasma discharge is always constant and the film quality is improved. A film having excellent properties is obtained.

Although not shown, the reaction chamber is covered with a top cover equipped with a reaction gas feed nozzle and / or parallel plate electrodes to seal the reaction chamber in an airtight structure.

A loader unit 22 for loading a wafer into the reaction chamber is housed inside the first preliminary chamber 12. Loader unit 22
Can be moved back and forth by a drive mechanism (not shown) arranged in the spare chamber. The loader unit 22 includes a wafer carrier arm 22a and a wafer carrier plate 22b.
Have. The carrier plate 22b is the carrier arm 2
It is screwed to 2a.

Next, the operation of loading the wafer into and out of the reaction chamber will be described.

A wafer cassette (not shown) is mounted on the upper part or the lower part of the hopper table 26. The wafer 24 supplied from the wafer cassette is placed on the hopper table 26 of the first wafer transfer mechanism 25 and is advanced by the belt drive or the air bear to reach the wafer track 30 of the wafer transfer fork 28.

When the first wafer detector detects a wafer, the first wafer transfer arm 32 vacuum-adsorbs the wafer from the lower side, rotates in that state, and the wafer transfer claw disposed under the first lid portion 34. The wafer is transferred to 36, and the wafer is placed on the claw. The first lid portion 34 has a viewing window 38. The first lid portion 34 is screwed or fixed to the vertically movable arm 42 of the first lid opening / closing mechanism 40. When the wafer 24 is placed on the wafer transfer claw 36, the vertically movable arm 42 descends,
The wafer enters the preparatory chamber through the first opening 44 formed in the upper portion of the first preparatory chamber 12, and the wafer is placed on the carrier plate 22b. The ascendable / descendable arm 42 is further lowered, the first lid portion 34 covers the first opening portion 44, and seals the first preliminary chamber 12.

After the first preliminary chamber is sealed, the first preliminary chamber is evacuated to a pressure equal to that of the reaction chamber. When the pressure becomes equal, a first gate valve (not shown) separating the first preliminary chamber and the reaction chamber is opened, and the wafer carrier plate 22b is advanced to the wafer mounting table 16 in the reaction chamber. When the carrier plate 22b reaches the predetermined position, the wafer receiving claw 18 moves up to receive the wafer from the carrier plate 22b. After that, the carrier arm 22a moves out of the reaction chamber, and the first
The gate valve is closed and the film formation reaction process is started.

Inside the second preliminary chamber 14, an unloader unit 46 for carrying out the film-forming processed wafer from the reaction chamber is housed. The unloader unit 46 can be moved back and forth by a drive mechanism (not shown) arranged in the spare chamber. The unloader unit 46 has a wafer carrier plate 46a and a wafer carrier plate 46b. Carrier plate 4
6b is screwed to the carrier arm 46a.

After the film formation reaction process is completed and the pressure in the second preliminary chamber 14 is made equal to the pressure in the reaction chamber 10, a second gate valve (not shown) that separates the reaction chamber and the second preliminary chamber is opened. .
The wafer for which the wafer receiving claw 18 has completed the film forming process lifts the wafer from the wafer mounting table 16. The carrier arm 46a of the unloader unit 46 advances and enters the lower side of the wafer lifted by the wafer receiving pawl 18. The wafer receiving claw 18 descends and mounts the wafer on the carrier plate 46b.

Thereafter, the carrier arm 46a withdraws from the reaction chamber, and when the carrier plate 46b reaches the position of the wafer transfer claw (not shown) arranged in the lower portion of the second lid portion 48, the retreat is stopped. The second gate valve is closed when the carrier plate 46b is completely withdrawn from the reaction chamber. The second lid portion 48 also has a viewing window 54. Second lid portion 48
Is screwed or fixed to the vertically movable arm 52 of the second lid opening / closing mechanism 50.

After the pressure in the second auxiliary chamber 14 is returned to atmospheric pressure, the vertically movable arm 52 of the second lid opening / closing mechanism 50 is raised. Second
A second opening 58 is provided at a position where the second lid is applied in the upper part of the preliminary chamber. The wafer held by the wafer transfer claw passes through the second opening 58 and goes out of the second preliminary chamber.

Then, the second wafer transfer mechanism 60 vacuum-sucks the wafer held by the wafer transfer claw and transfers it to the second wafer transfer mechanism 62. When the second wafer detector 66 detects that the wafer is placed on the wafer track 64 of the second wafer transfer mechanism 62, the wafer is sent to the magazine stacker table 68 by a conveyor or an air bear.

A cassette (not shown) is mounted on the upper or lower part of the magazine stacker table 68, the wafer sent to the magazine stacker table is stored, and the series of operations for one wafer is completed.

This operation is continuous and continuous for each wafer, and
It is done automatically. Since the cassette is placed under the atmospheric pressure outside the preliminary chamber, it can be replaced very easily without interrupting the film forming operation.

As mentioned above, the device of the present invention can be constructed in the so-called cassette-to-cassette format.

The apparatus of the present invention is a so-called "single wafer type" in which wafers are loaded / unloaded one by one onto the wafer mounting table in the reaction chamber. The single-wafer method is particularly suitable for depositing a CVD film having a uniform thickness on the surface of a large-diameter wafer of 8 inches or more. However, it can also be applied to a conventional batch type reaction chamber. However, although the batch reaction chamber is suitable for small-diameter wafers, the difference in film thickness density becomes too large for large-diameter wafers, and product quality tends to vary. Particularly, in the case of the plasma CVD method, the batch type is not preferable because the discharge density is not constant and the yield is reduced.

An air cylinder can be used to drive the lid opening / closing mechanism, the loader / unloader section, and the wafer receiving claws. Therefore, the peripheral drive system such as the exhaust system and the air compressor necessary for driving the apparatus of the present invention is arranged in the space 100 surrounded by the first preliminary chamber, the second preliminary chamber, the first wafer transfer mechanism and the second wafer transfer mechanism. can do. Thus, it is possible to manufacture a high quality semiconductor element while maintaining a high throughput, and to obtain an extremely compact CVD thin film forming apparatus which is excellent in basis efficiency in terms of apparatus design.

The apparatus of the present invention can be used for any type of CVD method including atmospheric pressure, reduced pressure and plasma.
It is preferably used for the method. It can also be used in the plasma etching method. Furthermore, as a recent technology, optical C
The VD method has been actively researched, and a device having a shape close to a practical machine is being prototyped. Naturally, the rectangular array method of the present invention
It can also be applied to this photo CVD apparatus.

[Effects of the Invention] As is clear from the above description, in the vapor phase reaction apparatus of the present invention, the first preliminary chamber, the second preliminary chamber, the first wafer transfer mechanism, the second wafer transfer mechanism and the reaction chamber Are arranged in a rectangular shape as a whole.

Therefore, various peripheral devices for the exhaust system and the drive system can be accommodated in this rectangular internal space. as a result,
The entire gas-phase reactor is grouped into a square shape, resulting in an extremely compact device with high basis efficiency. Further, it becomes possible to install a large number of units on the floor of a semiconductor manufacturing factory where space is limited.

Since the wafer mounting table is configured to be capable of responding to changes in the wafer diameter, it is not necessary to change the line configuration itself of the semiconductor manufacturing factory even when shifting from a 6-inch wafer to a 12-inch wafer, for example. As a result, the L-shaped array method of the present invention is more flexible than the conventional 180 ° array method.

Since the apparatus of the present invention is a cassette-to-cassette single-wafer type, it is possible to perform uniform film pressure CVD on a large-diameter wafer of 6 inches or more.
It is particularly suitable for forming a film. Since the whole device is extremely compact, even if it is a single-wafer type, if multiple devices are installed, it can achieve the same processing capacity as the Banz type. Even if a trouble should occur in one of them, all the devices are independent, so the other devices can continue operating without any influence. Therefore, the throughput is higher than that of a CVD apparatus of a multiple reaction chamber type or a batch type in which the whole operation must be stopped when a trouble occurs.

In addition, since the wafer transfer mechanism is arranged outside the auxiliary chamber, the cassette can be replaced very easily, and the wafer can be continuously and automatically operated for a long time without any interruption from loading to unloading.

To summarize the effects of the device of the present invention, it is possible to manufacture high-quality semiconductor devices with a high yield in a limited floor space while maintaining a high sleep level.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing one embodiment of the gas phase reaction apparatus of the present invention. 10 ... Reaction chamber 12 ... First preliminary chamber 14 ... Second preliminary chamber
16 ... Wafer mounting table 18 ... Wafer receiving claw 20 ... Shutter ring 22 ... Loader 22a and 46a ...
Wafer carrier arms 22b and 46b ... Wafer carrier plate 24 ... Wafer 25 ... First wafer transfer mechanism 26 ... Hopper table 28 ... Wafer transfer forks 30 and 64 ... Wafer track 32 ... First wafer transfer arm 34 ... First lid 36 ... Wafer transfer claws 38 and 54 ... Peep window 40 ... First lid opening / closing mechanism 42 and 52 ... Elevating arm 44 ... First opening 46 ... Unloader section 48 ... Second lid section 50 ... Second lid opening / closing mechanism 58 ... Second Opening 60 ... Second wafer transfer mechanism 62 ... Second wafer transfer mechanism 66 ... Second wafer detector 68 ... Magazine stacker table

Claims (2)

[Claims] 1. A gas phase reaction apparatus having a reaction chamber, a loader unit for loading a wafer into the reaction chamber, and an unloader unit for unloading a wafer from the reaction chamber, wherein the reaction chamber is a single-wafer type. The reaction chamber is a symmetric reaction chamber, in which a first preliminary chamber accommodating the loader section and a second preliminary chamber accommodating the unloader section are arranged in an L-shape so as to be substantially orthogonal to the reaction chamber, A first wafer transfer mechanism connected to the chamber and capable of mounting a wafer cassette on one end thereof, near the end of the first spare chamber on the side opposite to the reaction chamber connection side, orthogonal to the first spare chamber, and The second
A second wafer transfer mechanism, which is provided outside the first preliminary chamber in parallel with the preliminary chamber and can mount a wafer cassette on one end, is provided near the end of the second preliminary chamber opposite to the reaction chamber connection side. , So as to be orthogonal to the second auxiliary chamber, and the first
A lid that is provided outside the second preliminary chamber in parallel with the preliminary chamber, has a first opening for wafer loading on the upper surface of the first preliminary chamber, and has a wafer transfer claw at the bottom. And a first lid opening / closing mechanism including an opening / closing mechanism that opens and closes the first opening with the lid and that moves the lid up and down to transfer the wafer to and from the loader unit through the first opening. A second opening for carrying out a wafer is provided on the upper surface of the second preliminary chamber, and a lid having a wafer transfer claw at the bottom and the lid opens and closes the second opening. In addition, a second lid opening / closing mechanism including an elevating mechanism for elevating and lowering the lid to transfer the wafer and the unloader section through the second opening is provided. . 2. The first and second preliminary chambers are connected to a reaction chamber through a gate valve, and the reaction chamber is subjected to plasma CVD treatment or plasma etching treatment. The gas phase reactor described.