JPH06224144A - Processing apparatus - Google Patents

Abstract

PURPOSE:To provide a processing apparatus high in profitability and performance, wherein the apparatus can be lessened in inert gas consumption, a loading area can be charged with inert gas atmosphere of high purity to be kept at a positive pressure and prevented from rising abnormally in temperature, and a natural oxide film is restrained from being formed on a semiconductor wafer when the wafer is loaded or unloaded. CONSTITUTION:A processing apparatus main body 1 is demarcated into a processing chamber 41 wherein a semiconductor wafer 5 is processed and a loading area 13 equipped with a wafer boat 61 which loads or unloads the wafers 5 into or from the processing chamber 41. A gas inlet pipe 71 and a gas outlet pipe 72, which charge the loading area 13 with inert gas atmosphere and keep it positive in pressure, are provided, and a gas circulating/cooling/ cleansing system equipped with a gas circulating path 81 which enables inert gas to flow out of the loading area 13 and to return into it again, a blower 82, gas filters 83 and 85 which cleanse inert gas, and a cooler 84 which cools down inert gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus used in, for example, a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art For example, in a semiconductor process, various processing apparatuses for forming an oxide film on a semiconductor wafer, forming a thin film by a thermal CVD method, and forming a high impurity concentration region by a thermal diffusion method are available. It is used.

As a device applied to these various processing apparatuses, a vertical type heat treatment apparatus has been widely adopted in recent years, instead of a conventional horizontal type. The vertical heat treatment apparatus will be described below as an example.

This vertical heat treatment apparatus has a box-shaped apparatus body in which a processing chamber for performing a predetermined process on a semiconductor wafer as an object to be processed and a loading process for inserting / removing the semiconductor wafer into / from the processing chamber from below. A loading area having a mechanism, an area (I / O area) for loading / unloading a carrier containing a semiconductor wafer into / from the apparatus main body, a transfer stage for temporarily receiving this carrier, and this transfer stage And a transfer machine (wafer transfer) for transferring the semiconductor wafer in the carrier to the loading mechanism in the loading area.

In the processing chamber, a vertically long quartz process container (heating furnace) equipped with a heater is installed so that it can be opened downward. There is a loading area just below this processing chamber, and a wafer boat and a boat elevator as a loading mechanism are installed in this area.

In such a vertical heat treatment apparatus, when a carrier in which a large number of semiconductor wafers are aligned and stored is placed in the loading / unloading area of the apparatus main body, this carrier is placed on a transfer stage by a carrier transfer or the like. The semiconductor wafers in the carriers on the transfer stage are transferred to the wafer boat in the loading area one by one or five by the transfer machine and stored and held in a multistage state. In this state, the wafer boat is raised by the boat elevator to load the semiconductor wafer into the process container, and the process container is sealed and heated while the atmosphere is replaced with a predetermined processing gas atmosphere. Is processed.

The processed semiconductor wafer is lowered from the inside of the process container by the boat elevator together with the wafer boat and pulled out to the loading area directly below, and then returned to the carrier on the transfer stage by the transfer machine. The carrier is taken out from the loading / unloading area to the outside of the apparatus main body, or is transferred to the processing apparatus for the next process connected thereto.

In a processing operation in such a vertical heat treatment apparatus, when a semiconductor wafer is raised together with a wafer boat from a loading area to be inserted into a process container, or when the semiconductor wafer is lowered and pulled out from the process container after the process, in the middle thereof. Since there is a considerably high temperature atmosphere even near the furnace opening, if atmospheric air exists there, there is a problem that a natural oxide film is formed on the surface of the semiconductor wafer by O ₂ in the atmospheric air. Therefore, in order to perform such loading / unloading in an inert gas atmosphere (non-oxygen atmosphere) such as N ₂ gas, a gas is used as a closed system structure in which the loading area is separated from the atmosphere in the main body of the apparatus. It is desired to replace / maintain the atmosphere with N ₂ gas by supplying / discharging means.

Moreover, the gas atmosphere in the apparatus main body must be kept at a positive pressure at all times to prevent the invasion of the atmosphere from the outside, and the gas atmosphere in the apparatus main body is kept to repeat the semiconductor wafer processing operation. Gaseous impurities such as carbon are generated in the surface, or particulate impurities (particles) such as oil mist and dust are generated, and these impurities adhere to the semiconductor wafer or cause a chemical reaction (chemical contamination), resulting in a semiconductor element. It causes the deterioration of the characteristics and yield. At the same time, due to the release of hot air from the processing chamber, the radiant heat from the processed semiconductor wafer heated to a high temperature, etc., the N ₂ gas atmosphere in the loading area rises abnormally, and so on. While constantly introducing the inert gas into the main body of the device, the inert gas inside the main body of the device is constantly discharged to the outside together with impurities, and the atmosphere of the inert gas inside the main body of the device is maintained at high pressure with high purity. Is desired.

[0010]

However, in the case of the vertical heat treatment apparatus having the closed system structure as described above, the inside of the apparatus main body is replaced with and maintained in an inert gas atmosphere such as N ₂ gas, and abnormal temperature rise occurs. To prevent it, there is a problem of consuming a large amount of inert gas.

That is, since the apparatus main body of this type has a large box shape having a width and depth of about 1 meter and a height of about 2 meters, when the inside of the apparatus is first replaced with the inert gas, In addition, it is necessary to introduce a large amount of inert gas, and it takes a long time to sufficiently replace the gas, resulting in a reduction in the efficiency of the processing work. If you take a method of introducing an inert gas after evacuating with a vacuum pump, it is necessary to make the housing panel structure of the main body of the device airtight and thick and rigid enough to withstand negative pressure,
Invites higher production costs.

Further, in order to maintain the inert gas atmosphere in this large-sized apparatus main body at a positive pressure with high purity and prevent abnormal temperature rise, a large amount of clean inert gas is always introduced as a purge gas, while The inert gas in the main body of the apparatus must be constantly discharged together with impurities to the outside, the consumption amount of the inert gas becomes large, and the cost is uneconomical.

The present invention has been made in view of the above-mentioned circumstances, and the consumption of the inert gas is small, and even when the processing operation of the object to be processed is repeated, the loading area is kept at a positive pressure with a high purity. In addition to being able to maintain an active gas atmosphere, it is possible to prevent abnormal temperature rise, and suppress the formation of natural oxide films during loading / unloading of the object to be processed, adhesion of impurities to the object to be processed, and chemical reactions. The purpose of the present invention is to provide a very economical and high performance processing device which is very useful for

[0014]

In order to achieve the above-mentioned object, a processing apparatus according to the present invention inserts / removes an object to be processed into / from a processing chamber for performing a predetermined processing on the object in the apparatus body. And a gas supply / discharge means for replacing / maintaining a positive pressure inert gas atmosphere in the loading area.

A gas circulation path for discharging the inert gas in the loading area and returning it to the loading area again;
A gas circulation cooling and purifying system including a blower, a gas filter for purifying the inert gas, and a cooler for cooling the inert gas is provided in the gas circulation path.

[0016]

In the processing apparatus having the above structure, since the loading area divided into the apparatus main body is relatively narrow, it is possible to easily replace the atmosphere with the inert gas with a relatively small gas supply amount from the gas supply / discharge means. And even after this replacement,
By introducing the inert gas little by little by the gas supply / discharge means, the inside of the loading area can be maintained in a positive pressure inert gas atmosphere.

Moreover, even if the work of treating the object to be treated is repeated, the inert gas in the loading area is introduced into the gas circulation path of the gas circulation cooling and purification system by the blower, purified by the gas filter and the cooler. Since it is cooled by and returned to the inside of the loading area again, the inside of the loading area can be maintained in a high-purity inert gas atmosphere with positive pressure, and abnormal temperature rise can be prevented, and the inert gas as a whole is protected. Consumption is low, and it is possible to reduce costs, and to prevent the formation of natural oxide film during loading / unloading of the object to be processed into the processing chamber, adhesion of impurities to the object, and chemical reactions. It will be very helpful in suppressing.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the processing apparatus according to the present invention is applied to a vertical heat treatment apparatus will be described below with reference to the drawings. 1 is a vertical sectional view showing the configuration of the vertical heat treatment apparatus according to this embodiment, FIG. 2 is a vertical sectional view taken along the line AA of FIG. 1, FIG. 3 is a horizontal sectional view of the same, and FIG. Is BB in FIG.
Sectional drawing which follows the line, FIG. 5 is the schematic which shows a control system. This vertical heat treatment apparatus is used as an oxidation apparatus or a CVD apparatus for forming an insulating film on a semiconductor wafer as an object to be processed.

First, as shown in FIGS. 1 to 3, the vertical heat treatment apparatus according to this embodiment has an apparatus main body 1. The apparatus main body 1 has a large box-like structure using a housing panel 1a and has a width of 1 meter and a depth dimension of about 2 meters and a height of about 3 meters, and its front portion faces a clean room 2 in a factory. , And most of the others are installed in a maintenance room 4 which is isolated by the partition wall 3.

A processing chamber 10 for performing a predetermined process on a thin disk-shaped semiconductor wafer 5 as an object to be processed is partitioned by partition walls 11 and 12 in a substantially upper half of the rear part of the apparatus main body 1. The loading area 13 is partitioned just below the processing chamber 10 by the partition walls 12 and 14 so as to be airtight, and a plurality of semiconductor wafers 5, for example, 25 semiconductor wafers 5 are arranged in parallel in the front half of the apparatus main body 1. A loading / unloading area (I / O area) 15 for the carrier 6 stored and held in a state is partitioned from the processing chamber 10 and the loading area 13 by partition walls 11 and 14.

Further, a small pass box 16 having airtightness is fitted to a part of the partition wall 14 which divides the loading / unloading area 15 and the loading area 13 and is supported at an appropriate height via a stand 17. Transfer stages 18 are arranged in two upper and lower stages in the pass box 16,
The carriers 6 can be received one by one on their respective upper surfaces.

To describe the details of the respective parts, first, in order to carry the carrier 6 accommodating a plurality of semiconductor wafers 5 into the carry-in / carry-out area 15 and vice versa on the front panel of the apparatus main body 1. The front door 20 is provided so as to automatically open and close vertically.

In the loading / unloading area 15 inside thereof, two attitude changing mechanisms 21 as I / O ports on which the carriers 6 can be mounted are arranged on the left and right. The posture changing mechanism 21 functions to turn the carrier 6 placed on the upper surface in the upward state (the state in which the semiconductor wafer 5 is held upright) 90 degrees to be turned sideways, or conversely, to change the sideways state to the upward direction. It is a structure that makes up.

Further, in the loading / unloading area 15, the carrier transfer 22 is provided at a position immediately rearward of the posture changing mechanism 21.
Is installed so that it can be moved up and down via an elevator 23, and a carrier stock stage 24 is provided above the pass box 16 on the rear side thereof. It has a plurality of shelves 24a capable of storing the carriers 6 conveyed by the carrier transfer 22 from the posture changing mechanism 21 in two rows and four stages while keeping them in a horizontal orientation.

The atmosphere in the loading / unloading area 15 is atmospheric air. In order to remove adhered dust such as particles (fine particles) on the main surface of the semiconductor wafer 5 in each carrier 6 with clean air as much as possible. First, between the back surface of the carrier stock stage 24 and the partition wall 11 in the loading / unloading area 15, a vertically long first filter unit 25 having a filter and a fan is installed.
The first filter unit 25 has a clean air suction port 25a at the upper end that opens to the top plate portion of the apparatus main body 1, and sucks clean air in the maintenance room 4 from here to clean the carrier stock through the filter. The side flow can be performed toward the semiconductor wafer 5 in the horizontal state in the carrier 6 of the stage 24. A current plate 26 having a large number of holes formed therein is provided vertically on the front side of the carrier stock stage 24 to assist the side flow.

A second filter unit 27 having a built-in filter and fan is provided near the lower end of the straightening plate 26 on the front side.
Is installed, and while the clean air coming from the first filter unit 25 through the straightening vane 26 is cleaned again, the carrier 6 on the left and right posture changing mechanisms 21 below is cleaned.
Downflow can be performed toward the semiconductor wafer 5 in the vertical state.

Further, the floor plate of the apparatus body 1 which is directly under the same is provided with a drainage opening 28 in the shape of a drainboard, so that the clean air downstream from the second filter unit 27 is discharged to the maintenance room 4 outside the apparatus body 1. It is supposed to do.

The pass box 16 in which the transfer stages 18 are arranged in upper and lower two stages is a small (small capacity) vertically elongated box shape,
The side surface of the loading / unloading area 15 and the loading area 13
Auto doors 31 and 32 are provided on the side and the side, respectively.
Each of the automatic doors 31 and 32 has its own opening / closing drive unit, and can open / close alternately to communicate / block the loading / unloading area 15 and the loading area 13. When the automatic door 31 on the side of the loading / unloading area 15 is opened, the carriers 6 are loaded one by one onto the upper and lower two transfer stages 18 by the carrier transfer 22 or vice versa.

On the other hand, a vertical process container 41 is installed in the processing chamber 10. The process container 41 is a heating furnace called a process tube formed of, for example, quartz, and has an inverted U-shaped cross section, that is, a vertical substantially cylindrical shape with an upper end closed. A heater 42 is provided so as to surround the outer periphery of the process container 41, and a protective cover 43 in which a cooling pipe, a heat insulating material and the like are incorporated is further provided around the heater 42.
Is covered.

A manifold 44 is connected to the lower end of the opening of the process container 41. The manifold 44 is in the shape of a rectangular cylinder with upper and lower flanges. As shown in FIG. 1, an exhaust pipe 45 with an automatic damper 45a for exhausting the gas in the process container 41 is connected to the peripheral wall portion, and the tip of the exhaust pipe 45 is attached. It is led out of the apparatus main body 1 and connected to a factory exhaust device 46 (see FIG. 5). Further, a gas introduction pipe 56 for introducing new gas into the process container 41 via the manifold 44 is provided. A tip of the gas introduction pipe 56 is led out of the apparatus main body 1, and is connected to a predetermined process gas (processing gas) supply device 48 and an inert gas device 49 via an automatic switching valve 47 as shown in FIG. A process gas and an inert gas (for example, N ₂ gas in this embodiment) are alternately supplied to the process container 4
It can be introduced in 1.

Further, around the manifold 44 below the process vessel 41, an annular chamber-shaped scavenger 51 is constituted by the partition wall 12 and a square dish-shaped case 51a fixed to the lower surface thereof. A heat exhaust pipe 52 that constantly discharges heat and unnecessary gas accumulated around the lower part of the process container 41 is led out, and its tip is led out of the apparatus main body 1 and connected to a factory exhaust device 46 (see FIG. 5). . A branch pipe 54 with an automatic damper 54 a is provided in the process chamber 10 in the middle of the heat exhaust pipe 52.

The case 5 of the scavenger 51
The central portion of the bottom surface of 1a is opened so as to communicate with the lower end of the manifold 44, and constitutes the furnace opening 41a of the process container 41. An automatic shutter 55 is installed in the loading area 13 to close the furnace opening 41a from the lower surface side in an airtight state via an O-ring. The automatic shutter 55 opens and closes the furnace opening 41a by moving up and down and rotating in the lateral direction by the opening and closing drive section 55a.

In the loading area 13, a wafer boat 61 and a boat elevator 62 are installed as a loading mechanism for inserting / removing the semiconductor wafer 5 into / from the process container 41 of the processing chamber 10. The wafer boat 61 is made of quartz and is vertically long and has a structure in which a large number of semiconductor wafers 5 are housed and held in multiple stages in a horizontal state with vertical intervals.

The wafer boat 61 is vertically supported by a boat elevator 62 just below the furnace opening 41a of the process vessel 41. This wafer boat 61
With a large number of semiconductor wafers 5 housed therein, the boat elevator 62 raises and inserts it into the process container 41 with the opening of the shutter 55, or conversely lowers and pulls out from the process container 41. To do. It should be noted that the wafer boat 61 is raised and the process container 41 is raised.
When inserted inside, the flange 61a at the bottom of the wafer boat 61 closes the furnace opening 41a in place of the automatic shutter 55, so that the inside of the process container 41 can be sealed.

Further, between the wafer boat 61 and the pass box 16 in the loading area 13, a transfer machine (wafer transfer) 63 is installed so as to be vertically movable and supported by a transfer elevator 64. While the transfer machine 63 moves up and down, the semiconductor wafers 5 in the carrier 6 on the upper and lower transfer stages 18 in the pass box 16 are taken out one by one and stored in the wafer boat 61 in the loading area 13. Hold or vice versa
It functions to return the semiconductor wafer 5 from 1 into the carrier 6 on the transfer stage 18.

Here, the partition walls 12 and 1 are provided in the apparatus main body 1.
In order to replace / maintain the inside of the loading area 13 partitioned by 4 with a positive pressure inert gas atmosphere, a gas introduction pipe 71 and an exhaust pipe 72 as first gas supply / discharge means are provided.

The gas introducing pipe 71 is connected to the primary side (suction side) of the blower fan 82 in the middle of the gas circulation path 81 installed under the floor of the apparatus main body 1 as a gas circulation cooling and purification system described later. There is. This gas introduction pipe 7
1 is led out of the apparatus main body 1 and is connected to an inert gas supply device 49 via a flow rate adjusting valve 73 and a regulator 74 as shown in FIG. 5, and N ₂ gas as an inert gas is passed through the gas circulation path 81. It can be introduced into the loading area 13. The exhaust pipe 72 is led out from the downstream side in the loading area 13, has an automatic damper 72a in the middle thereof, and is connected to the above-described factory exhaust device 46.

At the time of initial replacement in the loading area 13, the automatic damper 72a is opened, and the factory exhaust device 46 exhausts the inside of the loading area 13 and introduces N ₂ gas at about 200 to 400 liters / min. In the steady state after the replacement, the N ₂ gas introduction amount is set to 50
Throttle to about 1 / min, the auto-damper 72a of the exhaust pipe 72 is closed, and the loading area 1 is closed by exhausting the clearance in the loading area 13 or the pressure adjusting damper.
The inside of 3 is maintained in an atmosphere of N ₂ gas having an appropriate positive pressure. In addition, the leak gas due to the clearance exhaust is the auto damper 54 of the heat exhaust pipe 52 of the scavenger 51.
Factory exhaust from the branch pipe 54 with a.

The gas circulation cooling and purification system maintains the N ₂ gas atmosphere in the loading area 13 at a high purity and prevents an abnormal temperature rise even when the semiconductor wafer 5 is repeatedly processed. In this system configuration, first, a N2 gas in the loading area 13 is first taken out of the system, and a gas circulation path 81 for purifying and cooling the N ₂ gas and then recirculating it back into the loading area 13 is provided under the floor of the apparatus main body 1. , A blower 82 is installed in the middle of this, and a chemical filter 83 as a gas filter is installed on the secondary side of the blower 82,
Further, a gas cooler 84 is installed on the secondary side thereof. The chemical filter 83 is a gas purifier in which a metal getter such as zirconia that absorbs gaseous impurities (moisture, oxygen, hydrocarbons, etc.) is replaceably incorporated according to the application. Further, the gas cooler 84 is a radiator type in which radiating fins are provided on a water-permeable cooling pipe, and has a cooling capacity such that the secondary side blown-out gas temperature becomes 50 ° C. or lower.

A particle filter 85 as a gas filter that receives the N ₂ gas from the gas circulation path 81 and blows it into the loading area 13 is provided on one side surface of the loading area 13. This particle filter 85 is a vertical type ULPA.
Grade absolute filter with filtering trapping particulate impurities N ₂ gas (particle such as dust), blow out the N ₂ gas from the one side in the loading area 13 in a horizontal laminar flow state. Further, in order to make the horizontal laminar flow state of the N ₂ gas more reliable, a straightening plate 86 having a large number of holes on the other side surface in the loading area 13 is vertically provided so as to face the filter 85. , Through this straightening plate 86 to the N ₂
The gas is sucked and conducted to the gas circulation path 81.

A gas shower mechanism 91 is provided above the loading area 13. The gas shower mechanism 91 is connected to the inert gas supply device 49 via a valve 92 and a regulator 73 as shown in FIG. 5, and a case of the scavenger 51 connected to the tip of the gas introduction pipe 94. A special nozzle 96 fixed to the lower surface of 51a via a bracket 95 is provided.

The special nozzle 96 is flat and has a width dimension capable of covering the entire area of the wafers having a diameter of 200 mm and a shape in which the landing (running) distance is as long as possible, and the wafer boat 61 is inserted into and removed from the process container 41 (loading). (/ Unloading), the N ₂ gas is made to flow horizontally from right next to the lower side of the furnace opening 41a of the process vessel 41 at 50 to 100 liter / min, and the ULPA filter 85 is used.
The wind velocity from the horizontal laminar wind (0.75m /
sec) and the semiconductor wafers 5 held in the wafer boat 61 in multiple stages by this N ₂ shower.
Impurities such as O ₂ and hot air are expelled from each other.

The pass box 16 is provided with a gas introduction pipe 101, an injector 102, and an exhaust pipe 103 as second gas supply / discharge means for replacing the inside of the box with an inert gas. The gas introduction pipe 101 is connected to an inert gas supply device 49 via a valve 104 and a regulator 93 as shown in FIG. 5, and its tip is connected to an injector 102 in the pass box 16 from above as shown in FIG. ing. By the injector 102, 50 liter / min of N ₂ gas can be constantly introduced and injected into the pass box 16 from one side, while the exhaust pipe 10 is provided on the other side opposite to this.
3 is connected, and this exhaust pipe 103 is connected to the auto damper 10
It is connected to a factory exhaust device 46 via 3a so that the gas in the pass box 16 can be constantly exhausted in a state of being flushed.

The injector 102 is a pipe-shaped injector vertically extending from the upper end to the vicinity of the lower end on one side of the pass box 16 and has a large number of small holes vertically formed on its peripheral surface. N ₂ gas is introduced from each of the small holes into the space above the upper and lower transfer stages 18 in the pass box 16 as a horizontal flow from one side. N ₂ gas blowing speed by the injector is 0.75 m / se
c is possible, and the carrier 6 on the transfer stage 18 has a large number of slits on both sides in a state of lying sideways. Therefore, N ₂ gas can flow through the slits inside the carrier 6 through the slits. Through the semiconductor wafer 5 in a direction (horizontal direction) parallel to the main surface of the semiconductor wafer 5 from one side to the other side, and impurities such as O ₂ between the semiconductor wafers 5 are expelled.

Further, as shown in FIG. 5, gas conducting pipes 111 and 112 as oxygen concentration detecting means in the loading area 13 and the pass box 16 are provided,
These are a common oxygen concentration meter (O ₂ sensor) 11
Connected to 3. The oxygen concentration meter 113 has a built-in three-way switching valve and a gas discharge pump, and measures whether the oxygen concentration in the loading area 13 and the pass box 16 is 20 PPm or less.

The controller 1 which receives the signal from the oxygen concentration meter 113 and the signal from the pressure sensor 114 for measuring the atmospheric pressure in the loading area 13
15 are provided. In response to a control command from the controller 115, the automatic dampers 45a, 54a
a, 72a, 103a and valves 47, 73, 92, 1
04, the front door 20, the automatic doors 31 and 32, the automatic shutter 55, the carrier transfer 22, the transfer machine 63, the boat elevator 62, and other operating units are automatically sequence-controlled.

The operation of the vertical heat treatment apparatus having such a structure will be described. First, since the loading area 13 defined in the apparatus body 1 is relatively narrow, at the time of initial replacement,
The auto-damper 72a of the exhaust pipe 72 as the first gas supply / discharge means is opened, the exhaust gas in the loading area 13 is exhausted by the factory exhaust device 46, and N ₂ gas is supplied from the gas introduction pipe 71 at about 400 liters / min. Introduce. With such a relatively small amount of N ₂ gas supplied, the atmosphere can be easily replaced with the inert gas.

In the stationary state after the replacement, the amount of N ₂ gas introduced from the gas introduction pipe 71 is reduced to a small amount of about 50 liters / min, the auto-damper 72a of the exhaust pipe 72 is closed, and the clearance in the loading area 13 is exhausted. Alternatively, a proper positive pressure is applied to the inside of the loading area 13 by the pressure adjusting damper (when the differential pressure between the clean room 2 and the maintenance room 4 is 0.6 to 0.7 mmH ₂ O, it is 0.2 mmH ₂ less than the atmospheric pressure of the clean room _2). N as high as 0.9 mmH ₂ O)
Maintain a ₂ gas atmosphere. The leak gas due to the clearance exhaust is constantly exhausted from the branch pipe 54 with the automatic damper 54a of the heat exhaust pipe 52 of the scavenger 51 to the factory.

On the other hand, in the pass box 16 surrounding the transfer stage 18, 50 liters / min is constantly supplied from the gas introduction pipe 101 as the second gas supply / discharge means via the injector 102.
The N ₂ gas is injected from one side in a horizontal flow and exhausted so as to be pushed out from the exhaust pipe 103 on the other side. By doing so, since the volume inside the pass box 16 is small, the atmosphere is quickly replaced with the inert gas with a very small amount of N ₂ gas supply.

In such a state, first, the front door 20 is automatically opened, and the carrier 6 accommodating a large number of semiconductor wafers 5 from the outside is installed in the loading / unloading area 15 as a left / right posture changing mechanism 21 as an I / O port. Each of them will be loaded and loaded. The posture changing mechanism 21 moves the carrier 6 from the upward position to the position 9
The carrier transfer 22 receives it one after another by turning it 0 degrees and turns it sideways. The carrier transfer 22 raises and lowers it via the elevator 23 and once conveys it to the upper carrier stock stage 24. In this state, the adhered dust such as particles (fine particles) on the main surface of the semiconductor wafer 5 in each carrier 6 is removed by clean air.

After this, at an appropriate timing, the automatic door 31 on the loading / unloading area 15 side of the pass box 16 is opened, and the carrier transfer 22 carries the carrier 6 from the carrier stock stage 24 to the upper and lower parts inside the pass box 16. It is carried in on the transfer stage 18 in stages.
At this time, the atmosphere temporarily enters the pass box 16, but after that, the auto door 31 is closed and the pass box 16 is closed.
By making the inside airtight, as described above, the gas introduction pipe 10
The N ₂ gas supplied from the No. 1 through the injector 102 expels the atmosphere in a short time and replaces it with an inert gas.

At this time, the injector 10 of the second gas supply / discharge means
The injector 2, which is No. 2, injects N ₂ gas from a large number of small holes into the space above the upper and lower transfer stages 18 in the pass box 16 from one side as a horizontal flow having a high flow velocity, so that A direction in which the N ₂ gas is parallel to the main surface of the semiconductor wafer 5 (horizontal direction) through a large number of slits on both side surfaces of the carrier 6 lying horizontally on each transfer stage 18 in the pass box 16. Then, the impurities flow out from one side to the other side, and again impurities such as O ₂ between the semiconductor wafers 5 are expelled and removed.

After the inside of the pass box 16 is replaced with the N ₂ gas atmosphere in this way, the automatic door 32 on the side of the loading area 13 is opened, and the inside of the carrier 6 on each of the upper and lower transfer stages 18 in the pass box 16 is opened. The semiconductor wafers 5 are taken out one by one by the transfer machine 63 and transferred to the wafer boat 61 of the loading mechanism. During this work, the inside of the pass box 16 is replaced with the N ₂ gas atmosphere, so there is no concern that the atmosphere or the like will enter the loading area 13.

A large number of semiconductor wafers 5 transferred to the wafer boat 61 in the loading area 13 are opened with the automatic shutter 55, and are raised together with the wafer boat 61 by the boat elevator 62 so that the processing chamber 1
0 is inserted into the process container 41. Then, with the furnace opening 41a closed with the lower flange 61a, the N ₂ gas atmosphere in the process container 41 is exhausted by the exhaust pipe 45, and the process gas is introduced into the process container 41 from the gas introduction pipe 56. The semiconductor wafer 5 is subjected to the required processing by heating the heater 42.

After the processing, the process gas in the process container 41 is exhausted from the exhaust pipe 45, and N ₂ gas is supplied from the gas introduction pipe 56 so that the inside of the process container 41 is the same as the inside of the loading area 13. Replace with ₂ gas atmosphere. Then, the boat elevator 62 descends and the processed semiconductor wafer 5 is pulled back into the loading area 13 together with the wafer boat 61. At that time, the automatic door 32 is opened again, the transfer machine 63 is operated, and the processed semiconductor wafer 5 in the wafer boat 61 is taken out and returned into the carrier 6 on the upper and lower transfer stages 18 in the pass box 16. . Then, the auto door 32 on the loading area 13 side is closed, the opposite auto door 31 is opened, and the carrier transfer 22 is operated to operate the carrier 6
Take out the carrier stock stage 24 once above
Transport to.

After that, the front door 2 of the loading / unloading area 15
0 opens, the carrier transfer 22 starts operating again,
The carriers 6 of the carrier stock stage 24 are successively transferred to the left and right posture changing mechanisms 21, and these are turned 90 degrees to the upward state. With this, the carrier 6 accommodating the processed semiconductor wafer 5 can be taken out to the outside.

By doing so, the atmosphere does not enter the loading area 13 when the semiconductor wafer 5 is loaded and unloaded, the total amount of inert gas consumed is small, and the cost is saved. In addition to the above, it is possible to maintain the inside of the loading area 13 in a high-purity inert gas atmosphere at a positive pressure, thereby generating a natural oxide film when loading / unloading the semiconductor wafer 5 into / from the process container 41, and It is very useful for suppressing the adhesion of impurities to 5 and the chemical reaction.

When the semiconductor wafer processing operation is repeated, particularly, the process container 4 of the wafer boat 61.
When inserting / removing to / from 1 ((load / unload), gaseous impurities such as carbon are generated in the N ₂ gas atmosphere in the loading area 13, and particulate impurities such as oil mist and dust are generated. However, the impurities adhere to the semiconductor wafer or cause a chemical reaction (chemical contamination), which causes deterioration of the characteristics and yield of the semiconductor element, and at the same time, the inside of the process container 41 is opened by opening the furnace opening 41a. Hot air release and high temperature (100
The N ₂ gas atmosphere in the loading area 13 rises abnormally due to radiant heat from the processed semiconductor wafer 5 heated to about 0 ° C.).

From the above, while the clean N ₂ gas is continuously supplied as the purge gas from the gas introduction pipe 71 as described above, the gas circulation cooling and purification system is constantly operated, and the N ₂ gas in the loading area 13 is impure. Along with the action of the blower 82, the gas is once conducted to the gas circulation path 81 via the rectifying plate 86, and this is passed through the chemical filter (gas purifier) 83 to the gaseous impurities (moisture, oxygen,
Hydrocarbons and others) are absorbed, and the N ₂ gas is passed through a gas cooler 84 to be cooled to 50 ° C. or lower. Further with filtered trapping particulate impurities N ₂ gas (particle such as dust) by the particle filter 85 of the absolute type of ULPA grade, horizontal laminar flow from one side to the loading area 13 the N ₂ gas It returns to the state by blowing it out.

Now, the N in the loading area 13 is
_{The 2} gas atmosphere is maintained at a high purity and abnormal temperature rise is prevented. Moreover, since N ₂ gas is blown from the filter 85 into the loading area 13 from one side in a horizontal laminar flow (laminar flow) state, even in the loading area 13, the wafer boat 61 is arranged in multiple stages and horizontally. Impurities such as O ₂ between the held large number of semiconductor wafers 5 are expelled and removed.

Further, at the time of loading / unloading the wafer boat 61 into / from the process container 41 (load / unload), the gas shower mechanism 91 is operated, and the N ₂ gas is rapidly supplied from the special nozzle 96 on the lower surface of the scavenger 51 to the furnace opening 41a. Impurities such as O ₂ and hot air between the semiconductor wafers 5 which are horizontally blown to the vicinity of the lower side from the side and are horizontally held in the wafer boat 61 are expelled by this N ₂ shower. Will be

Although the processing apparatus of the above-described embodiment is used as an oxidation apparatus or a CVD apparatus for forming an insulating film on the semiconductor wafer 5 as a processing object, the type of processing object and the type of processing. Is not particularly limited,
Of course, it may be a processing device that performs another type of processing. An inert gas other than the above-mentioned N ₂ gas may be supplied depending on the type of these treatments.

[0063]

Since the processing apparatus of the present invention is constructed as described above, the consumption of the inert gas is small, and even if the processing operation of the object to be processed is repeated, the loading area is kept at a high positive pressure. It is possible to maintain a pure inert gas atmosphere, prevent abnormal temperature rise, generate a natural oxide film when loading / unloading the processing object into the processing chamber, and attach impurities or chemical reactions to the processing object. It is very useful for suppressing the above, and it is very economical and can achieve high performance.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of a vertical heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view of the device.

FIG. 4 is a sectional view taken along the line BB of FIG.

FIG. 5 is a schematic diagram showing a control system.

[Explanation of symbols]

1 ... Device body, 5 ... Object to be processed (semiconductor wafer), 10 ...
Processing chamber (41 ... Process container), 13 ... Loading area, 61, 62 ... Loading mechanism (61 ... Wafer boat, 62 ... Boat elevator), 71, 72 ... Gas supply / discharge means (71 ... Gas introduction pipe, 72 ... Gas) Exhaust pipe), 81
~ 85 ... Gas circulation cooling purification system (81 ... Gas circulation path, 82 ... Blower, 83, 85 ... Gas filter, 84 ...
Cooler.

Claims (3)

[Claims] 1. A loading area having a loading mechanism for inserting / removing an object to be processed is defined in a processing chamber for subjecting the object to be processed in a predetermined manner in the main body of the apparatus.
A processing apparatus comprising a gas supply / discharge means for replacing / maintaining the inside of this loading area with a positive pressure inert gas atmosphere, in which the inert gas in the loading area is discharged and returned to the loading area again. A processing apparatus comprising: a path; and a gas circulation cooling / purification system including a blower, a gas filter for purifying an inert gas, and a cooler for cooling the inert gas, which is provided in the gas circulation path. 2. The gas circulation cooling / purification system is configured to blow out the cooled / purified inert gas in a horizontal laminar flow state from one side surface to the other side surface in the loading area. Item 1. The processing device according to item 1. 3. The gas circulation cooling purification system is provided with, as gas filters, a chemical filter for absorbing gaseous impurities in an inert gas and a particle filter for collecting particulate impurities by filtration. The processing apparatus according to claim 1, wherein the processing apparatus is a processing apparatus.