JP3470701B2 - Load lock device and its operation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load lock apparatus which uses little wasteful nitrogen gas and has low operating cost. SOLUTION: A first supply passage 11 is connected to a first load lock chamber L1 for supply nitrogen gas via a first supply valve V1 to the first load lock chamber. A first discharge passage 12 is connected to the first load lock chamber for discharging gas in the chamber. A second supply passage 13 is connected to a second load lock chamber L2 for supplying nitrogen gas via a second supply valve V3 to the chamber L2, and a second discharge passage 14 is connected to the chamber L2 to discharge gas in the chamber L2. A pressure-equalizing passage 15, having a pressure equalizing valve V5 disposed therein, is connected across a point between the first valve V1 and first chamber L1 and a point between the second valve V3 and second chamber L2. The valve V5 is opened to guide the nitrogen gas at atmospheric pressure in the chamber L1, which accommodates an unprocessed wafer into the second chamber L2, accommodating a processed wafer via the passage 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load lock device used in a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Conventionally, as a load lock device of this type, there is one as shown in FIG. 3 (Japanese Patent Laid-Open No. 8-1811).
No. 83). The load lock device 50 is connected to a vacuum transfer chamber 51 that transfers a wafer under vacuum. The vacuum transfer chamber 51 is connected to a processing chamber (not shown) that performs processes such as molecular diffusion and etching on the wafer. The load-lock device 50 has a first load-lock chamber 53 through which an unprocessed wafer is transferred from outside to the vacuum transfer chamber 51, and a through-hole when a processed wafer processed in the processing chamber is taken out to the outside. And a second load lock chamber 54.

An unprocessed wafer is externally inserted into a first load-lock chamber 53 at atmospheric pressure filled with nitrogen gas by closing the gate valve 56 on the side of the vacuum transfer chamber.
Gate valve 57 provided outside the load lock chamber
And the inside of the first load lock chamber 53 is evacuated.
Thereafter, the gate valve 56 on the vacuum transfer chamber side of the first load lock chamber 53 is opened, and the unprocessed wafer is processed from the first load lock chamber 53 by a robot arm (not shown) provided in the vacuum transfer chamber 51. Transport to room. The processed wafer, which has undergone molecular diffusion in this processing chamber, is transferred from the processing chamber to the second load lock chamber 54 by the robot arm. After that, the gate valve 58 on the vacuum transfer chamber side of the second load lock chamber is closed, nitrogen gas is supplied to the second load lock chamber 54, and the pressure is increased to atmospheric pressure.
The gate valve 59 on the outside of the second load lock chamber is opened to take out the processed wafer in the second load lock chamber 54 to the outside.

The load lock device 50 carries in an unprocessed wafer into the vacuum transfer chamber 51 via the first load lock chamber 53 in order to improve the operation rate of the processing chamber.
At the same time, the processed wafers are taken out from the vacuum transfer chamber 51 passing through the second load lock chamber 54. That is, evacuation of the first load lock chamber 53 at about atmospheric pressure and supply of nitrogen gas to the second load lock chamber 54 at about vacuum are simultaneously executed to increase the throughput.

[0005]

However, in the conventional load lock device 50, the first load lock chamber 53 is evacuated from the atmospheric pressure and the second load lock chamber 54 is evacuated from the vacuum. Since the supply of nitrogen gas up to atmospheric pressure is executed, there is a problem that the amount of nitrogen gas consumed and the power for vacuuming are large. That is, almost all of the nitrogen gas in the first load lock chamber 53 is exhausted, while the second gas of the substantially vacuum is discharged.
Since all of the nitrogen gas is newly supplied to the load lock chamber 54, there is a problem that a large amount of nitrogen gas is wasted and the operating cost is high.

Therefore, an object of the present invention is to provide a load lock device in which the waste of nitrogen gas is small and the operating cost is low.

[0007]

In order to achieve the above object, the load lock apparatus according to the invention of claim 1 has a first load lock chamber through which an unprocessed wafer is transferred from outside to a vacuum transfer chamber. A second load lock chamber through which the processed wafer is taken out from the vacuum transfer chamber to the outside, a pressure equalizing passage connecting the first load lock chamber and the second load lock chamber, and the pressure equalizing passage. And a pressure equalizing valve interposed between the two.

According to the load lock device of the first aspect, the unprocessed wafer is put into the first load lock chamber from the outside. At this time, the first load lock chamber is filled with a predetermined gas and has the same pressure as the outside. On the other hand, the processed wafer is put from the vacuum transfer chamber into the substantially vacuum second load lock chamber. At this time, the second load lock chamber has substantially the same vacuum as the vacuum transfer chamber. After that, the pressure equalizing valve is opened to connect the first load lock chamber and the second load lock chamber via the pressure equalizing passage. Then,
Due to the pressure difference between the first load lock chamber and the second load lock chamber, the gas in the first load lock chamber flows into the second load lock chamber, and the first load lock chamber and the second load lock chamber are separated from each other. The pressure is almost the same. That is, the gas discharge from the first load-lock chamber and the gas supply to the second load-lock chamber are simultaneously performed only by opening the pressure equalizing valve. Since it is not necessary to evacuate and supply the gas to the second load lock chamber by using power, energy consumption is small. Further, since the exhaust gas from the first load lock chamber is diverted and supplied to the second load lock chamber, almost all of the gas in the first load lock chamber is discharged and the second load lock chamber is discharged as in the conventional case. The amount of gas consumed is greatly reduced compared to the case where gas is newly supplied to the load lock chamber from approximately vacuum to approximately atmospheric pressure.

A load lock device according to a second aspect of the present invention is the load lock device according to the first aspect, wherein a first supply valve is provided to supply gas to the first load lock chamber. And a second supply valve is installed,
A second supply passage for supplying gas to the second load lock chamber, wherein the pressure equalizing passage includes the first supply valve and the first supply valve.
It is characterized in that a connection is made between the load lock chamber and the second supply valve and the second load lock chamber.

According to the load lock device of the second aspect, an unprocessed wafer is placed in the first load lock chamber and the second load lock chamber is operated.
The processed wafer is put in the load lock chamber, and the pressure equalizing valve provided in the pressure equalizing passage is opened. Then, due to the difference in atmospheric pressure between the first load lock chamber and the second load lock chamber, the gas in the first load lock chamber passes through the first supply passage, the pressure equalizing passage, and the second supply passage to the second supply passage. It flows into the load lock chamber. That is, the exhaust gas from the first load lock chamber is diverted as the supply gas to the second load lock chamber. Therefore, this load lock device has the same structure as the conventional one, except that the gas is discharged from the first load lock chamber and the second load lock chamber is discharged.
Since it is not necessary to supply gas to the load lock chamber by using power, energy consumption can be reduced and gas consumption can be significantly reduced.

A third aspect of the load lock device according to the first aspect is the load lock device according to the first aspect, wherein a first discharge valve is provided to discharge gas from the first load lock chamber. And a second discharge passage through which a second discharge valve is provided to discharge gas from the second load lock chamber, wherein the pressure equalizing passage is formed between the first discharge valve and the first load lock chamber. And the second discharge valve and the second load lock chamber are connected to each other.

According to the load lock device of the third aspect, an unprocessed wafer is placed in the first load lock chamber and the second load lock chamber is operated.
The processed wafer is put in the load lock chamber, and the pressure equalizing valve provided in the pressure equalizing passage is opened. Then, due to the difference in atmospheric pressure between the first load lock chamber and the second load lock chamber, the gas in the first load lock chamber passes through the first discharge passage, the pressure equalizing passage, and the second discharge passage, It flows into the load lock chamber. That is, the exhaust gas from the first load lock chamber is diverted as the supply gas to the second load lock chamber. Therefore, this load lock device has the same structure as the conventional one, except that the gas is discharged from the first load lock chamber and the second load lock chamber is discharged.
Since it is not necessary to supply gas to the load lock chamber using power, energy consumption can be reduced and waste of gas can be significantly reduced.

According to a fourth aspect of the present invention, in the method of operating the load lock device, gas is supplied to the first load lock chamber before the unprocessed wafer is externally inserted, and the first load lock chamber is set to a substantially atmospheric pressure. And a step of bringing the second load lock chamber into a substantially vacuum state before collecting the processed wafer from the vacuum transfer chamber into the second load lock chamber, and inserting the unprocessed wafer into an atmospheric pressure. The gas in the first load lock chamber is transferred to the second load lock chamber in which the processed wafer is collected and is in a substantially vacuum state, and the first load lock chamber and the second load lock chamber are separated from each other. Step of equalizing pressure and first step of equalizing pressure and inserting the unprocessed wafer
A step of bringing the load lock chamber into a substantially vacuum state and supplying gas to the second load lock chamber in which the pressure is equalized and the processed wafer is collected, and the second load lock chamber is brought to a substantially atmospheric pressure. And a step of performing.

According to the method of operating the load lock device of the fourth aspect, after the gas is supplied to the first load lock chamber to make it substantially atmospheric pressure, an unprocessed wafer is externally inserted into the first load lock chamber. On the other hand, after the second load lock chamber has been evacuated to a substantially vacuum state, the processed wafer is recovered from the vacuum transfer chamber in the second load lock chamber. After that, the gas in the first load lock chamber at approximately atmospheric pressure is transferred to the second load lock chamber in approximately vacuum to equalize the pressures in the first load lock chamber and the second load lock chamber. Then, the first load-lock chamber is pressure-equalized to further discharge gas to make the first load-lock chamber substantially vacuum, while the second load-lock chamber pressure-equalized is further supplied with substantially large gas. Set to atmospheric pressure. As a result, the first
Energy consumption because the gas discharge from the first load lock chamber and the gas supply to the second load lock chamber until the pressures in the load lock chamber and the second load lock chamber are equalized can be performed without using power. The amount can be smaller than before.
In addition, the exhaust gas from the first load lock chamber is
Since it is diverted as the supply gas to the load lock chamber, waste of the above gas is reduced.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a diagram showing a load lock device according to the present invention, and FIG. 2 is a schematic diagram showing a semiconductor manufacturing apparatus constructed by using the above load lock device. As shown in FIG. 2, the load lock device 1 is connected to a vacuum transfer chamber 2 that transfers a wafer under vacuum. The vacuum transfer chamber 2 is connected to a processing chamber 3 for diffusing molecules on a wafer. The load lock device 1 includes the first load lock chamber L
1 and a second load lock chamber L2, both of which are connected to the vacuum transfer chamber 2. The first load-lock chamber L1 is used for processing unprocessed wafers to be processed in the processing chamber 3.
This is a room through which the vacuum transfer chamber 2 is transferred from the outside. The second load lock chamber L2 is a chamber through which the processed wafer processed in the processing chamber 3 is taken out from the vacuum transfer chamber 2 to the outside. The first load lock chamber L1 is provided with a first gate valve 5 at the inlet from the outside and a second gate valve 6 at the outlet to the vacuum transfer chamber 2.
Equipped with. The second load lock chamber L2 includes a third gate valve 8 at the inlet from the vacuum transfer chamber 2 and a fourth gate valve 9 at the outlet to the outside.

The first and second load lock chambers L1,
A passage for supplying nitrogen gas and a passage for discharging the gas in the room are connected to L2. That is, as shown in FIG. 1, the first supply valve V is connected to the first load lock chamber L1.
1 is a first supply passage 11 for supplying nitrogen gas.
And a first exhaust valve V2 is interposed to connect the first exhaust passage 12 for exhausting the gas in the room. In the second load lock chamber L2, a second supply valve V3 is installed to supply a nitrogen gas to the second supply passage 13, and a second discharge valve V4 is installed to discharge a gas in the room. Discharge passage 1
4 are connected. The first supply passage 11 and the second supply passage 13 are connected to a nitrogen gas cylinder (not shown). The first discharge passage 12 and the second discharge passage 14
Is connected to a vacuum pump (not shown). First above
The supply valve V1 and the first load lock chamber L1 are connected to each other, and the second supply valve V3 and the second load lock chamber L2 are connected to each other by a pressure equalizing passage 15 provided with a pressure equalizing valve V5. There is.

The load lock device configured as described above operates as follows.

First, the first load lock chamber L1 is
Nitrogen gas is supplied through the supply passage 11 to bring the first load lock chamber L1 to a substantially atmospheric pressure, and the gas in the second load lock chamber L2 is discharged through the second discharge passage 14, The second load lock chamber L2 is kept in a substantially vacuum state. Subsequently, an unprocessed wafer to be processed in the processing chamber 3 is externally inserted into the first load lock chamber L1 at atmospheric pressure as shown by an arrow A by a transfer device (not shown) arranged outside. After that, the first gate valve 5 is closed,
The first load lock chamber L1 is closed. On the other hand, a processed wafer which has already been processed in the processing chamber 3 is transferred to a substantially vacuum second load lock chamber L2 by a robot arm (not shown) provided in the vacuum transfer chamber 2 as shown by an arrow B. . After that, the third gate valve 8 is closed and the second gate valve 8 is closed.
Seal the load lock chamber.

Next, the pressure equalizing valve V5 is opened. Then, the first load lock chamber L1 and the second load lock chamber L2 communicate with each other through the first supply passage 11, the pressure equalizing passage 15, and the second supply passage 13. Then, the gas mainly containing nitrogen gas flows from the first load lock chamber L1 to the second load lock chamber L2 due to the pressure difference between the first load lock chamber L1 and the second load lock chamber L2. As a result, the first load lock chamber L1 and the second load lock chamber L2 are pressure-equalized. Then, the pressure equalizing valve V5
Close.

Then, the first discharge valve V2 is opened to further discharge the pressure-equalized gas in the first load lock chamber L1 from the first discharge passage. As a result, the first load lock chamber L1 is brought into a substantially vacuum state. Then, the first discharge valve V2 is closed. Then, the second gate valve 6 is opened, and the unprocessed wafer in the first load lock chamber L1 is unloaded to the vacuum transfer chamber 2 by the robot arm in the vacuum transfer chamber 2 as indicated by arrow C, and the vacuum is transferred to the vacuum transfer chamber 2. After passing through the transfer chamber 2,
It is transported to the processing chamber 3.

On the other hand, in the pressure-balanced second load-lock chamber L2, the second supply valve V3 is opened, and nitrogen gas is supplied into the second load-lock chamber L2 through the second supply passage 13. As a result, the second load lock chamber L2 is brought to approximately atmospheric pressure. Then, the second supply valve V3 is closed.
Then, the fourth gate valve 9 is opened, and the processed wafer in the second load lock chamber L2 is taken out to the outside by the external transfer device as shown by the arrow D.

In this way, the load lock device 1 is
Is the discharge of gas from the first load lock chamber L1 and the second
The supply of gas to the load lock chamber L2 can be executed without using power by only opening the pressure equalizing valve V5. Therefore, the load lock device 1 consumes less energy than in the conventional case where the evacuation of the first load lock chamber and the supply of gas to the second load lock chamber are all performed using power. it can. Further, since the exhaust gas from the first load lock chamber L1 is diverted as the supply gas to the second load lock chamber L2, a gas containing nitrogen gas in the first load lock chamber at approximately atmospheric pressure is used as in the conventional case. On the other hand, the amount of nitrogen gas consumed can be significantly reduced compared to the case where nitrogen gas is newly supplied to the substantially vacuum second load lock chamber to bring it to atmospheric pressure. As a result, the operating cost of this load lock device can be reduced.

In the above embodiment, the first supply valve V1 and the first load lock chamber L1 and the second supply valve V3 and the second load lock chamber L2 are connected by the pressure equalizing passage. However, even if the first discharge valve V2 and the first load lock chamber L1 and the second discharge valve V4 and the second load lock chamber L2 are connected by a pressure equalizing passage, the load of the above-described embodiment is A load lock device having the same function as the lock device is obtained. Alternatively, the first load lock chamber L1 and the second load lock chamber L2 may be directly connected by a pressure equalizing passage provided with a pressure equalizing valve.

In the above embodiment, nitrogen gas was supplied to the first and second load lock chambers L1 and L2 as an example of gas, but a gas other than nitrogen gas may be supplied.

[0026]

As is apparent from the above, according to the load lock device of the first aspect of the present invention, the first load lock chamber through which the unprocessed wafer is passed and the second load lock chamber through which the processed wafer is passed. , The first load lock chamber and the second
Since the pressure-equalizing passage that connects the load-lock chamber and the pressure-equalizing valve provided in the pressure-equalizing passage are provided, the first load-lock chamber at approximately atmospheric pressure containing the unprocessed wafer and the processed wafer are provided. By opening the pressure equalizing valve and communicating with the second load lock chamber of a substantially vacuum state in which the gas is stored in the first load lock chamber, the gas in the first load lock chamber is introduced into the second load lock chamber by the first load lock chamber. Gas discharge in lock chamber and second
The gas can be supplied to the load lock chamber at the same time. Therefore, as in the conventional case, the first
Since it is not necessary to evacuate the load lock chamber and supply gas to the second load lock chamber using power, energy consumption can be reduced. Further, since the exhaust gas from the first load lock chamber is diverted and supplied to the second load lock chamber, the gas consumption amount can be significantly reduced as compared with the conventional case, and thus the operating cost of the load lock device can be reduced. .

A load lock device according to a second aspect of the present invention is the load lock device according to the first aspect, wherein a first supply valve is provided to supply a gas to the first load lock chamber, A second supply valve is provided to supply gas to the second load lock chamber, and the pressure equalizing passage is provided between the first supply valve and the first load lock chamber, and Since the second supply valve and the second load lock chamber are connected, open the pressure equalizing valve,
The gas in the first load-lock chamber at approximately atmospheric pressure can be guided to the substantially vacuum second load-lock chamber through the first supply passage, the pressure equalizing passage, and the second supply passage. The discharge of gas from the chamber and the supply of gas to the second load lock chamber can be performed with less energy consumption than before, and the waste of gas is significantly reduced, reducing the operating cost of the load lock device. it can.

A load lock device according to a third aspect of the present invention is the load lock device according to the first aspect, wherein a first discharge valve is provided to discharge gas from the first load lock chamber. And a second discharge passage through which a second discharge valve is provided to discharge gas from the second load lock chamber, wherein the pressure equalizing passage is formed between the first discharge valve and the first load lock chamber. And the second discharge valve and the second load lock chamber are connected to each other, so that the pressure equalizing valve is opened and the gas in the first load lock chamber at approximately atmospheric pressure is discharged to the first discharge passage. Since it can be guided to the substantially vacuum second load lock chamber through the pressure equalizing passage and the second discharge passage, the gas is discharged from the first load lock chamber and the second load lock chamber is discharged.
Gas can be supplied to the load lock chamber with less energy consumption than before, and the waste of gas can be significantly reduced, so that the operating cost of the load lock device can be reduced.

According to a fourth aspect of the present invention, in the method of operating the load lock device, before the unprocessed wafer is inserted into the first load lock chamber from the outside, gas is supplied to bring the first load lock chamber to a substantially atmospheric pressure. A step of collecting the processed wafer from the vacuum transfer chamber to the second load lock chamber before bringing the second load lock chamber into a substantially vacuum state, and inserting the unprocessed wafer,
And, the gas in the first load-lock chamber at approximately atmospheric pressure is transferred to the second load-lock chamber in which the processed wafer is collected and is substantially vacuum, so that the first load-lock chamber and the second load-lock chamber are separated from each other. Pressure equalizing step, a step of substantially equalizing the pressure equalized first load lock chamber, and a step of supplying gas to the pressure equalized second load lock chamber to bring the second load lock chamber to approximately atmospheric pressure. Since the exhaust gas from the first load lock chamber is transferred to the second load lock chamber as the supply gas and diverted, the energy consumption during the operation of the load lock device can be reduced as compared with the conventional one. In addition, the consumption of the gas can be reduced, and the operating cost of the load lock device can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a load lock device according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a semiconductor manufacturing apparatus configured using the load lock device of FIG.

FIG. 3 is a diagram showing a conventional load lock device.

[Explanation of symbols]

1 load lock device 11 First supply passage 12 First discharge passage 13 Second supply passage 14 Second discharge passage 15 Pressure equalizing passage L1 1st load lock room L2 2nd load lock room V1 first supply valve V2 first discharge valve V3 second supply valve V4 second discharge valve V5 pressure equalizing valve

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/68 B01J 3/02 H01L 21/3065 H01L 21/31

Claims (4)

(57) [Claims] 1. A first load lock chamber (L1) through which an unprocessed wafer is transferred from outside to a vacuum transfer chamber (2), and a processed wafer from the vacuum transfer chamber (2) to the outside. A second load lock chamber (L2) through which the pressure equalization passage (15) connects the first load lock chamber (L1) and the second load lock chamber (L2); 15) A pressure equalizing valve (V5) interposed in the load lock device. 2. The load lock device according to claim 1, wherein a first supply valve (V1) is provided to supply gas to the first load lock chamber (L1).
1) and a second supply valve (V3) are provided to supply gas to the second load lock chamber (L2).
3) and the pressure equalizing passage (15) is provided with the first supply valve (V1).
And a first load lock chamber (L1) and a connection between the second supply valve (V3) and the second load lock chamber (L2). 3. The load lock device according to claim 1, wherein a first discharge valve (V2) is provided to discharge gas from the first load lock chamber (L1).
2) and a second discharge valve (V4) are interposed to discharge the gas from the second load lock chamber (L2).
4), the pressure equalizing passage is provided between the first discharge valve (V2) and the first load lock chamber (L1), and between the second discharge valve (V4) and the second load lock chamber (L2). ) Is connected to the load lock device. 4. A gas is supplied to the first load-lock chamber (L1) before the unprocessed wafer is externally inserted, and the first load-lock chamber (L1) is supplied with a gas.
The step of bringing the load-lock chamber (L1) to substantially atmospheric pressure, and the step of collecting the processed wafers from the vacuum transfer chamber (2) into the second load-lock chamber (L2).
Step 2) in which the processed wafer is recovered and the gas in the first load-lock chamber (L1) in which the unprocessed wafer is inserted and which is substantially at atmospheric pressure is recovered. Moving the second load lock chamber (L2) to a vacuum and equalizing the pressure of the first load lock chamber (L1) and the second load lock chamber (L2); A step of making the first load lock chamber (L1) in which the processed wafer is inserted into a substantially vacuum state, and a gas are supplied to the second load lock chamber (L2) in which the pressure is equalized and the processed wafer is collected. Supply, the second
And a step of bringing the load lock chamber (L2) to substantially atmospheric pressure.