JPH0582622A - Mechanical interface device - Google Patents

Abstract

PURPOSE:To provide an inert gas replaceable mechanical interface device because the influence by a natural oxide film on the surface of a wafer due to oxygen contained in the air becomes a serious problem and so the movement, carriage, processing, etc., of the wafer are required to be done in an inert gas (N2 gas) atmosphere in order to prevent the growth of the natural oxide film. CONSTITUTION:The air in a main body case 1 is replaced with N2 gas to make the inside of the case 1 have an N2 gas atmosphere and so the inside of a pod POD 10 keeps an N2 gas atmosphere. Each time the pod is set on a roof 2 of the main body case 1, the air of the inside of the pod is replaced with N2 gas for making the inside of the pod have a higher-purity N2 gas atmosphere. N2 gas is introduced into the inside of the pod from the main body case 1, with the pod being airtightly closed with a pod door 21. For this reason, a double ring compound bellows 50 is located airtightly and serves as an energizing device with the plurality of pre-load springs inside the bellows and thereby the pod door can be lowered by any specified height.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical interface device used in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art Conventionally, semiconductor processing has been carried out in a specially designed clean room in order to prevent particle contamination of the semiconductor, but there is a problem that it is too expensive including maintenance. Since there is a limit to the reduction of the contamination level of particle contamination, for example, Japanese Patent Laid-Open No.
A standardized mechanical interface device (SMIF device) has been developed as disclosed in the publication 0-143623.

This SMIF device, for example, as shown in FIG. 4, contains a wafer processing device (not shown), is filled with clean air, and has a main body case 1 and a portable type box (hereinafter It includes a pod POD) 10 and a carrier device 30. Body case 1 of the device body
Ports (loading / unloading port of the wafer cassette 20) 4 are formed on the top plate 2 by the port plate 3, and the pod POD 10 having the grip portion 10A is placed on the port plate 3. The pod POD 10 has a shape having an annular flange 12 around the opening 11.
The transport device 30 in this example is an elevating device, and an elevating shaft 32
The wafer cassette 20 is placed on an elevating table 31 supported by an elevating table 31 and is moved up and down. This elevating table 31 is a port door. The main body case 1 against the outside, and the wafer cassette 2 on the port door 31.
The table 21 of 0 abuts on the peripheral portion of the opening 11 of the pod POD 10 to seal the opening 11. Hereinafter, this stand 21 will be referred to as a pod door. 13 is a sealing material, which is a pod PO
The opening of D10 and the pod door 21 are sealed, the sealing material 14 seals between the flange 12 of the pod POD10 and the port plate 3, and the sealing material 15 seals between the port plate 3 and the port door 31. .. A lock mechanism 40 has a lock lever 41 driven by a geared motor (not shown), and serves to push down the flange 12 of the pod POD 10 onto the port plate 3. In this example, after the unprocessed wafer W is transferred onto the port door 31 from another location (not shown), the pod POD 10 is mounted on the port plate 3 and fixed by the lock lever 41. After fixing with the lock lever 41, the port door 31 is lowered to the transfer position. When the port door 31 descends to the transfer position, a transfer device (not shown) transfers the wafer cassette 20 on the port door 31 to the processing machine.

[0004]

By the way, conventionally, the particle contamination of the wafer W has been a problem, but as the density of the semiconductor integrated circuit is increased, a natural oxide film on the wafer surface due to oxygen in the air is generated. The influence begins to become a problem, and in order to prevent the growth of this natural oxide film, the movement of the wafer W,
It has become necessary to carry out the treatment, treatment, etc. in an inert gas (N ₂ gas) atmosphere. Currently, the concentration of O ₂ and H ₂ O is 10 p.
An N ₂ gas atmosphere of pm or less is required.

When using the above-mentioned SMIF device,
And N ₂ gas atmosphere of air in the main body case 1 is replaced with N ₂ gas, the interior of the pod POD10 is being kept in N ₂ gas atmosphere, the pod POD10 is set on the top plate 2 of the casing 1 Each time, the inside is replaced with N ₂ gas again to obtain a higher purity N ₂ gas atmosphere.
Injection of N ₂ gas to the pod POD10 a portable type, it is necessary to perform the N ₂ gas cylinder provided in the main body case 1 side, while sealing the pod POD10 in the pod door 21, N ₂ from the casing 1 side Injecting gas is not easy and is structurally complex.

The present invention has been made in order to solve this problem, and it is possible to easily replace the gas in the pod, and to provide a mechanical interface device that can replace the gas only by adding a simple member. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention, in claim 1, is mounted on a port plate which is provided in a main body case and forms a port for loading / unloading an object to be processed. A pod with an opening flange that covers the port, a pod door that can close the opening of the pod, and a port door that is supported in the main body case so as to be able to move up and down and that engages with the port plate at the time of maximum rise to close the port,
In the mechanical interface device for transporting the pod door from the inside of the pod to the main body case and vice versa, the port door defines a tubular space in which the port door can move up and down by a predetermined height and the port plate A movable port skirt having an upper engaging peripheral portion that can be airtightly engaged with the lower surface, and a biasing member that is disposed on the port door or a member that moves up and down together with the port door and that biases the port skirt toward the port plate. The port plate has an exhaust port opening to the inner peripheral surface and an air supply port opening to the inner peripheral surface and connected to an N ₂ gas source. A plurality of preload springs interposed between the base fixed to the shaft and the lower flange of the port skirt, wherein the base and the lower flange of the port skirt are Double chain-like bellows surrounding the lower opening of the port skirt is disposed airtightly between said plurality of preloaded spring is disposed within the bellows, when N ₂ gas injection into the pod The port door is configured to be driven down by an arbitrary predetermined height.

According to a second aspect of the present invention, the arbitrary predetermined height at which the port door descends is within a range in which the tensile force applied to the port skirt by the displacement of the bellows due to the port door descending does not exceed the spring force of the preload spring. Is characterized in that

According to a third aspect of the present invention, the base has a hole opening inside the bellows, and a pipe extending to the outside of the main body case is connected to the hole.

According to a fourth aspect of the present invention, after the pod is set on the port plate, the port door is lowered to an arbitrary predetermined height, and after the sealed space is formed, the exhaust port is closed and N _{2 is} supplied from the air supply port.
The gas is injected for a predetermined time or until the oxygen concentration becomes a predetermined value or less, and then the port door is lowered to the workpiece transfer position.

According to a fifth aspect of the present invention, before the port door is lowered, N ₂
It is characterized in that gas is blown into the port.

[0012]

In the present invention, when injecting gas into the pod, the port door may be lowered by an arbitrary height to inject N ₂ gas. As the port door descends, the spring of the biasing device contracts, but since the spring is preloaded so that a sufficient biasing force acts on the port skirt, the port skirt remains pressed against the port plate. As the port door descends with the port door, the pod opening opens, but the lower end of the port skirt is sealed with bellows, and the inside of the port skirt is airtightly shielded from the outside. The inside of the pod is airtightly shielded from the outside, and the pod opening opens, so that the gas supply port and the gas exhaust port communicate with the inside of the pod.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 33 denotes a short cylindrical port skirt, which defines an internal space A in which a port door 31 can move up and down, and has a lower engaging peripheral portion (downward) facing inward at its lower end. A flange) 33A is formed, and a plurality of guide holes 33a are formed in the lower flange 33A. Further, an outwardly facing upper engagement peripheral portion (upper flange) 33B is formed on the upper end portion of the port skirt 33.

A pedestal 71 serving as a spring seat is fixed to the elevating shaft 32 of the port door 31, and a plurality of coil springs 70 for pushing up are preloaded between the pedestal 71 and the lower flange 33A of the port skirt 33. It is arranged in the state.

Reference numeral 50 designates a double ring bellows consisting of an inner bellows 51A and an outer bellows 51B.
And the lower flange 33A of the port skirt 33 are airtightly attached so as to surround the lower opening of the port skirt 33.
It is arranged inside. The pedestal 71 is formed with a vent hole 71A that opens into a space formed by the inner bellows 51A and the outer bellows 51B. 72 is piping,
One end is connected to the vent hole 71A, and the other end is drawn out of the main body case 1 through a filter (not shown).

Reference numeral 3A is a gas supply port that penetrates the lower side of the port plate 3 in the radial direction and is connected to an N ₂ gas cylinder (not shown) through a pipe 3a. 3B is a gas exhaust port that penetrates the lower side of the port plate 3 in the radial direction, and 3C is an electromagnetic valve provided in the pipe 3b.

The inside of the box body case 1 is in a N ₂ gas atmosphere and is constantly pressurized by injecting 20 L / min of N ₂ gas.

Next, the operation of this embodiment will be described with reference to FIGS.

Now, it is assumed that the pod POD 10 is transferred from the outside of the apparatus to the port plate 3 of the main body case 1 and fixed to the port plate 3 by the lock lever 41 (not shown). In this state, the opening 11 of the pod POD 10 and the pod door 21 are sealed with the sealing material 13, and the flange 12 of the pod POD 10 and the port plate 3 are sealed with the sealing material 14. The port skirt 33 is biased upward by the coil spring 70,
Moreover, the engagement peripheral portion 33B is pressed against the lower surface of the port plate 3 via the sealing material 33b, and the sealing material 33b seals between the port skirt 33 and the port plate 3.

Next, N ₂ gas is injected into the pod POD10 to replace the inside with N ₂ gas. Before the gas injection, the port door 31 is lowered by a predetermined small distance as shown in FIG. Let This small distance may be any distance within a range in which the extension displacement of the bellows 50 due to the lowering of the elevating shaft 32 does not exert a tensile force on the port skirt 33. The joint portion 33b is in pressure contact with the lower surface of the port plate 3 via the sealing material 33b.

The coil spring 70 extends as the port door 31 descends, and even if it extends to some extent, the port skirt 33 extends.
Since the coil spring 70 is preloaded so that a sufficient pressing force acts on the coil spring 70, the tensile force of the bellows 50 is applied to the coil spring 7.
As long as the preload of 0 is not exceeded, the port skirt 33 remains in pressure contact with the port plate 3. When the port door 31 descends, the pod door 21 also descends together with the port door 31, so that the opening 11 of the pod POD 10 opens, but the lower opening of the port skirt 33 is sealed by the bellows 50, and the inside of the port skirt 33 is the main body case. 1 is in a state of being hermetically shielded from the inside of the pod POD10.
There is no possibility that the air inside will enter the body case 1. As the port door 31 and the pod door 21 descend, the opening 11 of the pod POD10 opens, so that the gas supply port 3A and the gas exhaust port 3B communicate with the inside of the pod POD10.

In the present embodiment, as described above, after the port door 31 is lowered to open the opening 11 of the pod POD10, the solenoid valve 3C is opened, and N ₂ gas is supplied from the gas supply port 3A into the pod POD10. To, for example, 70 liters / minute,
It is injected for about 5 minutes, and the air in the pod POD10 is exhausted from the gas exhaust port 3B to replace the inside of the pod POD10 with N ₂ gas.

When the gas replacement is completed, the port door 31 is lowered to a predetermined position (transfer position) as shown in FIG. As a result, the pod POD10 communicates with the inside of the main body case 1, but the inside of the pod POD10 is N ₂
Since it is in a gas atmosphere, N ₂ in the concentrated body case 1
There is no fear that the gas concentration will decrease. When the port door 31 is lowered to the transfer position, the wafer cassette 20 on the port door 31 is carried to the processing apparatus side in the N ₂ gas atmosphere by a transfer device (not shown).

The wafer cassette 20 processed by the processing apparatus is transferred to the port door 31 by the transfer device (not shown).
It is transferred to the top and the pod POD is opened by the port door 31.
After being carried in, the port door 31 is raised to the highest position to seal the port 4 and then carried out of the apparatus.

In this embodiment, after the wafer cassette 20 containing the unprocessed wafers is transferred onto the port door 31 which closes the port 4, the pod POD 10 is set on the port plate 3. , The port door 31 descends by a predetermined small distance to form a sealed space A, and after the sealed space A is formed, the inside of the pod POD 10 is N
After the inside of the pod POD 10 is exchanged with the inside of the main body case 1 after the inside of the pod POD 10 is replaced with ₂ gas and the inside of the pod POD 10 becomes an N ₂ gas atmosphere, there is no possibility that external air or dust is brought into the main body case 1.

In the structure without the bellows 50 of this embodiment,
It is necessary to lower the port door 31 onto the lower flange 33A to form the sealed space A. In this configuration, the inside of the pod POD10 is kept inside the pod door 21 until the port door 31 comes into close contact with the lower flange 33A. The pod POD 10 communicates with the inside of the main body case 1 through the peripheral side surface and the gap formed between the peripheral side surface of the port door 31 and the port skirt 22, and the lower opening of the port skirt 33.
There is a risk that dust and the like inside may enter the body case 1, but the bellows 50 of the present embodiment surely prevents this.

Further, in this embodiment, since the preload spring 70 is arranged in the bellows 50, there is no possibility that dust generated from the preload spring 70 will be dissipated in the main body case 1.

In this embodiment, since the bellows 50 hermetically closes the lower opening of the port skirt 33 when the pod POD 10 is set on the port plate 3 of the main body case 1 from the outside of the apparatus, the port door 31 is closed. Before opening the opening of the pod POD10 that has descended, the solenoid valve 3C is opened and N ₂ gas is blown into the port 4 from the gas supply port 3A to clean the surface of the port door 31 and the surface of the pod door 21. There is an advantage that can be.

In the above description, N in the pod POD 10
₂ Gas injection amount is specified by time, but gas exhaust port 3
In some cases, an oxygen concentration meter is provided in the exhaust system including B, and the injection of N ₂ gas is stopped when the measured oxygen concentration becomes a predetermined value or less.

In the above embodiment, the case in which the main body case 1 accommodates the wafer processing apparatus has been described, but the main body case 1 may be a stocker in which the atmosphere is N ₂ gas.

[0032]

As described above, according to the present invention, the port door is lowered to a predetermined height to form a sealed section communicating with the pod, and an N ₂ gas source external to the pod is introduced into the pod through the sealed section. _Because it is configured to inject ₂ gases,
Since it is only necessary to provide the member for partitioning the sealed section in cooperation with the port door and the pod door, it is possible to construct a highly reliable pod gas replacement system at a low cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a state when N ₂ gas is injected in the above embodiment.

FIG. 3 is a vertical cross-sectional view showing a state during a process of loading / unloading an object to be processed in the above embodiment.

FIG. 4 is a diagram showing an outline of a conventional SMIF device.

[Explanation of symbols]

 1 Body Case 3 Port Plate 3A Air Supply Port 3B Exhaust Port 3C Solenoid Valve 4 Port 10 Pod POD 11 Pod POD Opening 12 Pod POD Flange 13-14 Sealing Material 20 Wafer Cassette 21 Pod Door 31 Port Door 32 Lifting Shaft 33 Port Skirt 33A Lower engagement peripheral part of port skirt 33B Upper engagement peripheral part of port skirt 33b Seal material 40 Lock mechanism 50 Bellows 51A Inner bellows 51B Outer bellows 70 Coil spring 71 which is a biasing device 71 Pedestal 71a Vent hole 72 Piping A Sealed space

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiya Morita 100 Takegahana-cho, Ise-shi, Mie Shinko Electric Co., Ltd.Ise Plant (72) Inventor Kono, 100 Takegahana-cho, Ise-shi, Mie Shinko Electric Co., Ltd. Ise In-house (72) Inventor Atsushi Okuno 100, Takegahana-cho, Ise-shi, Mie Shinko Electric Co., Ltd.In Ise Works (72) Inventor Masanori Tsuda 100, Takegahana-cho, Ise-shi, Mie Shinko Electric Co., Ltd. (72) Invention Mitsuhiro Hayashi, 100, Takegahana-cho, Ise City, Mie Prefecture Shinko Electric Co., Ltd.

Claims (5)

[Claims] 1. A device provided on the main body case for carrying in an object to be processed,
A pod with an opening flange that is placed on a port plate that forms a port for carrying out and covers the port, a pod door that can close the opening of this pod, and a pedestal that is supported in the main body case so as to be able to move up and down A mechanical interface device having a port door for engaging and closing the port, the port door transporting the pod door from the inside of the pod to the main body case and vice versa, in which the port door can move up and down by a predetermined height. A movable port skirt which has an upper engaging peripheral portion which is airtightly engageable with the lower surface of the port plate and which defines a cylindrical space inside,
The port door is provided with a biasing device that is disposed on the port door or a member that moves up and down together with the port door and biases the port skirt toward the port plate. is connected to the N ₂ gas source as well as an opening to the surface having the air supply opening, the biasing device is interposed between the lower flange of the anchored platform and port skirt elevation axis of the port door A plurality of preload springs, in which a double ring-shaped bellows surrounding the lower opening of the port skirt is airtightly disposed between the base and the lower flange of the port skirt. Is a mechanical interface device disposed in the bellows, wherein the port door is driven to descend at an arbitrary predetermined height when N ₂ gas is injected into the pod. 2. The arbitrary predetermined height at which the port door descends is within a range in which the tensile force applied to the port skirt by the displacement of the bellows due to the port door descending does not exceed the spring force of the preload spring. The mechanical interface device according to claim 1. 3. The mechanical interface device according to claim 1, wherein the pedestal has a hole opening inside the bellows, and a pipe extending to the outside of the main body case is connected to the hole. .. 4. After the pod is set on the port plate, the port door descends to a predetermined height to form a sealed space, and then the exhaust port is closed to supply N ₂ gas from the air supply port for a predetermined time or Inject until the oxygen concentration is below the specified value,
The mechanical interface device according to any one of claims 1 to 3, wherein the port door is then lowered to the workpiece transfer position. 5. The N ₂ gas is blown into the port before the port door is lowered.
4. The mechanical interface device according to any one of 4 above.