JPH06104182A - Method and apparatus for filling gas - Google Patents

Abstract

PURPOSE:To contract a gas filling time and reduce a cost, by injecting the gas into a container performing at least once the changeover of gas filling modes with respect to a plurality of gas filling modes for injecting the gas into the container. CONSTITUTION:A wafer to be subjected to a dry etching processing is fixed in a chamber 1, and the chamber 1 is sealed. Then, a closing valve 12 is released by a sequencer 13, and the air, etc., in the chamber 1 are sucked by a vacuum pump 5 via a suction port 1d. When the internal vacuum state of the chamber 1 becomes a predetermined one, the dry etching processing is performed. Thereafter, an inert gas F for destroying the vacuum state is injected into the chamber 1 from a blow-off port 1c. At this time, initially, the inert gas F is injected in a constant-flow-rate mode, and when the pressure in the chamber 1 becomes a predetermined value, the constant-flow-rate mode is changed over into a time-proportional mode or into a constant-draft mode. thereby, since a gas filling time can be contracted without increasing the number of upflung particles, the cycle time of the whole of a semiconductor manufacturing process can be contracted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas filling method and a filling device for injecting an inert gas or the like into a vacuum chamber in a gas supply apparatus used in an industrial manufacturing apparatus such as a semiconductor manufacturing apparatus. is there.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor manufacturing process, in a dry etching process, a low pressure CVD process, etc., a chamber, which is a closed container, is temporarily evacuated and then an inert gas is injected to break the vacuum. It is being appreciated. At this time, there has been a problem that a minute amount of minute particles adhering to the chamber wall or the like is rolled up in the chamber when the inert gas is injected and adheres onto the wafer to deteriorate the yield of semiconductor products.

This has become a serious problem as the density of semiconductor products has increased in recent years. Conventionally, it is known empirically that if an inert gas is injected over a long period of time to perform vacuum break, particles will not be rolled up, and the yield of semiconductor products will be improved. It was carried out to inject the inert gas over the time.

[0004]

However, with the recent increase in the price of semiconductor manufacturing equipment, it is necessary to shorten the cycle time in order to reduce the cost, and the inert gas is filled in the semiconductor manufacturing process. I couldn't afford to spend a long time. Therefore, there is a need for a new method for filling a vacuum chamber with an inert gas in a short time without winding up particles.

An object of the present invention is to provide a gas filling method and a gas filling device which can shorten the gas filling time without increasing the number of particles to be wound up.

[0006]

In order to achieve this object, the gas filling method of the present invention is designed so that the gas inside the sealed container is sucked into the container and the inside of the container is evacuated. A gas filling method for injecting, wherein a plurality of gas filling modes for injecting gas into a container are switched at least once to inject gas into the container. Here, two or more of the plurality of gas filling modes are selected from a constant flow rate mode, a constant flow rate time mode, a constant airflow velocity mode, and a constant wall airflow force mode.

In order to achieve this object, the gas filling apparatus of the present invention comprises a closed container, a vacuum device for sucking the gas inside the container to make the inside of the container a vacuum, and a gas for the container. A gas filling device having a gas filling means for injecting, wherein the gas filling means has a plurality of gas filling modes for injecting the gas into the container and switches the gas filling mode at least once to inject the gas into the container. It has a control means for controlling. Here, two or more of the plurality of gas filling modes are selected from a constant flow rate mode, a constant flow rate time mode, a constant airflow velocity mode, and a constant wall airflow force mode.

[0008]

The gas filling method of the present invention having the above structure is
After the gas inside the sealed container is sucked to make the inside of the container a vacuum, the gas is injected into the container. Here, it is an object of the present invention to reduce the winding of particles adhering to the wall surface in the container and to shorten the gas filling time. In the gas filling method of the present invention, the control device controls two or more of a plurality of gas filling modes for injecting gas into the container, among a constant flow rate mode, a constant flow rate time mode, a constant airflow velocity mode and a constant wall airflow force mode. It is stored and the user can select any one mode. Further, the user can switch the plurality of gas filling modes by the control device while filling the closed container with the gas.

In the time proportional mode or the constant airflow mode, particles are less likely to be rolled up even when the gas is filled in a shorter time than the constant flow rate mode. However, since the flow rate is low from the start of gas filling to a certain time,
The total gas filling time cannot be shortened further. Therefore, by controlling the flow rate in the constant flow rate mode from the start of gas filling to a fixed time, it is possible to shorten the gas filling time without increasing particles.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An inert gas filling method and an inert gas filling apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows the configuration of the experimental apparatus for the inert gas filling apparatus. This experimental device is an experimental device for measuring the number of particles, and unlike the device actually used in the semiconductor manufacturing process, a wafer handling device and the like are omitted.

The chamber 1, which is a closed container, has a cylindrical shape with a diameter of 400 mm and a height of 200 mm. An inert gas outlet 1c is formed on the side surface of the chamber 1. A storage tank for the inert gas F is connected to the outlet 1c via a flow control valve 3, a flow meter 4, and an opening / closing valve 14. The control device of the flow control valve 3 includes a driver circuit 6,
It is connected to a personal computer 10 via a pulse generator 7 and a PIO board 8. Further, the flow meter 4 is A
It is connected to a personal computer 10 via a D board 9.

A particulate counting port 1a is formed on the side surface of the chamber 1 at a position facing the inert gas blowing port 1c. The particle counter 1a is connected to the particle counter 2 via an opening / closing valve 11. In addition, a suction port 1d for making the inside of the chamber 1 into a vacuum state is formed on the side surface of the chamber 1. The suction port 1d is connected to a vacuum pump 5, which is a vacuum device, via an opening / closing valve 12. Further, the control units of the on-off valves 11, 12, 14 are electromagnetic valves 13 a, 1 connected to the sequencer 13.
It is connected to 3b and 13c.

Next, the operation of the inert gas filling device having the above structure will be described. A wafer handling device (not shown) takes out the wafer which has been dry-etched from the open chamber 1 and transfers it to the next process. Then, the wafer to be dry-etched next is fixed in the chamber 1, and the chamber is sealed. Next, the on-off valve 12 is opened by the sequencer 13, and the vacuum pump 5 sucks air and the like in the chamber through the suction port 1d. When the inside of the chamber 1 becomes a predetermined vacuum state,
A corrosive gas is supplied onto the wafer through a supply port (not shown) to perform dry etching processing. After a lapse of a predetermined dry etching time, an inert gas F for breaking the vacuum state is injected into the chamber 1 through the blowout port 1c.

At this time, since the main part of the present invention is in what mode the inert gas F is filled, it will be described in detail with reference to experimental data. As the filling mode,
Experiments were conducted on the following four modes. (1) Constant Filling Flow Rate Mode The constant filling flow rate mode is the filling time t as shown in FIG.
This is a mode in which the valve opening is the same with respect to (unit: minutes) and the inert gas filling flow rate QUB is made constant.

(2) Filling flow time proportional mode In the filling flow time proportional mode, as shown in FIG. 8, the filling flow rate QUB of the inert gas F is increased in proportion to the elapse of the filling time t (unit: minutes). It is a mode to let.

(3) Filling air velocity constant mode The filling air velocity constant mode is the filling time t (unit: minutes).
On the other hand, the mode is a mode in which the filling flow rate of the inert gas F is controlled so that the flow velocity of the outlet 1c of the chamber 1 is always constant. At this time, the relationship between the filling time t and the filling flow rate QUB is as shown in FIG.

(4) Constant wall airflow force mode In the constant wall airflow force mode, the airflow force acting on the particles existing on the wall surface inside the chamber 1 is constant with respect to the filling time t (unit: minutes). In addition, it is a mode in which the filling flow rate of the inert gas F is controlled. At this time, the relationship between the filling time t and the filling flow rate QUB is as shown in FIG.

An experiment was carried out for the above four modes by counting the number of particles wound in the air by the experimental apparatus shown in FIG. The filling time t is an experimental factor to be changed.
It was adopted. The filling time t means a time required from when the inside of the chamber 1 is in a vacuum state to when the inert gas F is injected into the chamber 1 and reaches atmospheric pressure (760 torr).
The reason why the gas filling time t is used as an experimental factor is that the purpose of the present invention is to shorten the gas filling time t while suppressing the curling of particles to a low level. 4 above
For each mode, the particle counter 2 counts the number of particles rolled up by changing the filling time t through the particle counter 1a.

Next, the procedure of the experiment will be described in detail with reference to FIG. First, the filling mode and the filling time t are set in the sequencer 13 (S1). Next, the particle counter 2 is started (S2). Next, the inside of the chamber 1 is cleaned to keep the internal state of the chamber 1 constant (S
3). That is, the chamber 1 is rapidly filled with clean air of class 10 or lower through the outlet 1c. After that, the air inside the chamber 1 is sucked by the vacuum pump 5 through the suction port 1d. By repeating this 12 times, chamber 1
The weight of the particles inside was 5 mg.

Next, the vacuum pump 5 is started (S4),
The vacuum pump 5 is stopped at a vacuum pressure of 1 torr (S5).
Next, experimental pseudo particles are charged through the particle charging port 1b above the chamber 1 (S6). The pseudo particles used here are made of polymethylmethacrylate and have a particle size of ◯. 35-0.5 μm, specific gravity 1.19, PH
It is a fine white powder particle of 6.5 to 7.0.

Next, after 10 minutes have passed, the inert gas F is started to be injected from the outlet 1c (S7), and the filling is finished within a predetermined filling time. At this time, the pressure in the chamber 1 is atmospheric pressure (760 torr) (S8). next,
Inert gas F in chamber 1 to particle counter 2
Suction is started (S9). Then, counting of particles is started after 5 seconds (S10). The particles were counted for 1 minute at a sampling rate of 300 cc / min.

FIG. 4 shows the experimental results when the filling time t was changed from 60 to 600 seconds. The experimental result of the constant flow rate mode is shown by 21, the experimental result of the time proportional mode is shown by 22, the experimental result of the constant flow velocity mode is shown by 23, and the experimental result of the constant wall airflow force mode is shown by 24. In the constant filling flow rate mode 21, it was found that there is an inflection point at which the particles abruptly increase near the filling time of 100 to 200 seconds. FIG. 5 shows data of the additional experiment in the vicinity of the inflection point in the constant filling flow mode.

FIG. 6 shows data obtained by increasing the number of experiments with the filling time t being 40 to 100 seconds. As seen in FIG. 6, there is almost no difference between the flow rate modes except that the number of particles rapidly increases when the filling time t is set to 50 seconds or less in the constant flow rate mode. In each mode, the number of particles to be rolled up increases as the filling time t becomes shorter, and it is considered that the particles to be rolled up have little influence on the semiconductor process when the filling time t is 60 seconds or more.

On the other hand, the increase in the internal pressure of the chamber 1 in each mode is constantly increased in the constant flow rate mode 26 and is initially increased in the time proportional mode 28 and the constant air force mode 27, as shown in FIG. The amount is small and increases rapidly in the second half. Here, when the increase rate of the internal pressure is high, the wind speed of the inert gas F blown in becomes high, and when the increase rate of the internal pressure is low, the wind speed of the inert gas F blown in becomes slow. This relationship becomes clearer when viewed as data of the flow rate and the internal pressure of the chamber 1 in each mode as shown in FIG.
That is, in the constant flow rate mode 29, the flow rate is always constant even if the pressure in the chamber 1 increases, whereas in the time proportional mode and the constant air force mode, the flow rate increases as the pressure in the chamber 1 increases. To increase.

Further, FIG. 1 shows the chamber pressure and the inert gas F when the filling time t is set to 60 seconds in the experimental result of FIG.
It is a graph which shows the relationship with the flow rate of. Filling time t = 60
It is considered that the second is a limit in which the particles are less likely to be rolled up in each mode and the influence of the particles on the semiconductor process is small.

Therefore, in consideration of FIGS. 1 and 2, in order to prevent the particles from being wound up and to shorten the filling time t, the inert gas F is supplied in the constant flow rate mode until the chamber internal pressure reaches 200 torr. When the pressure in the chamber is 200 torr or more, the time K shown in FIG. 2 can be shortened by switching to the time proportional mode or the constant airflow mode and filling the inert gas F.

As a gas filling mode, a constant flow rate mode,
The control for the inert gas F to flow from the outlet 1c into the four modes of the flow rate proportional mode, the constant airflow velocity mode and the constant wall airflow force mode is stored in the personal computer 10 and executed. That is, the flow meter 4
According to the measurement value of the inert gas F of each flow rate of FIG. 7 to FIG.
The personal computer 10 controls the flow valve 3 so that the air flows out from the air outlet 1c. At the beginning of gas filling, the flow rate of gas filling is controlled in the constant flow rate mode, and the chamber 1
Switching the flow rate control to the time proportional mode or the constant airflow force mode when the internal pressure reaches a predetermined value is stored in the personal computer 10 as a control device.
To be executed.

After the vacuum breaking is completed by filling with the inert gas, the chamber 1 is opened and the wafer is taken out. According to the gas filling method and the gas filling apparatus of the embodiment of the present invention, when the inert gas F is filled in the vacuum chamber 1, the inert gas F is first injected in the constant flow rate mode,
Since the mode is switched to the time proportional mode or the constant air force mode when the pressure in the chamber 1 reaches a predetermined value, the filling time t can be increased without increasing the number of particles to be rolled up.
Therefore, the cycle time of the entire semiconductor manufacturing process can be shortened, and the cost of the semiconductor product can be reduced.

In the present embodiment, the case where the gas filling mode is switched once from the constant flow rate mode to the time proportional mode or the constant air flow force mode has been described, but other modes may be switched and used. In some cases, 2
You may switch more than once. Further, in this embodiment, as the gas filling mode, a constant flow rate mode, a flow rate time proportional mode,
Although the four modes of the constant airflow velocity mode and the constant wall airflow force mode have been described, it is presumed that switching between modes is effective even when other modes are used.

[0030]

As is apparent from the above description, according to the gas filling method and the gas filling apparatus of the present invention, when the gas is filled into the vacuum-sealed container, the gas is injected in the constant flow rate mode at the beginning. However, since the time proportional mode or the air force constant mode is switched when the pressure in the closed container reaches a predetermined value, the filling time t can be shortened without increasing the number of particles to be rolled up.
The overall cycle time of the semiconductor manufacturing process can be shortened, and the cost of semiconductor products can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a gas filling method according to an embodiment of the present invention.

FIG. 2 is a data diagram showing the relationship between the chamber internal pressure and the gas filling time.

FIG. 3 is a conceptual diagram showing a configuration of a gas filling device that is an embodiment of the present invention.

FIG. 4 is a first data diagram showing the relationship between the number of particles wound up and the gas filling time.

FIG. 5 is a second data diagram showing the relationship between the number of particles wound up and the gas filling time.

FIG. 6 is a third data diagram showing the relationship between the number of particles wound up and the gas filling time.

FIG. 7 is an explanatory diagram of a constant filling flow rate mode.

FIG. 8 is an explanatory diagram of a filling flow rate time proportional mode.

FIG. 9 is an explanatory diagram of a filling airflow velocity constant mode.

FIG. 10 is an explanatory diagram of a wall airflow force constant mode.

FIG. 11 is a flowchart of an experimental method for obtaining the relationship between the gas filling method and the particle winding.

[Explanation of symbols]

 1 Chamber 2 Particle Counter 3 Flow Control Valve 4 Flow Meter 5 Vacuum Pump 10 Personal Computer

Claims (4)

[Claims] 1. A gas filling method for injecting gas into the container after sucking gas inside the closed container to evacuate the container and then injecting the gas into the container. Is switched at least once to inject the gas into the container. 2. The gas filling method according to claim 1, wherein the plurality of gas filling modes include two or more of a constant flow rate mode, a constant flow rate time mode, a constant airflow velocity mode, and a constant wall airflow force mode. A gas filling method characterized by being selected. 3. A gas filling device comprising a closed container, a vacuum device for sucking gas inside the container to evacuate the inside of the container, and a gas filling device for injecting gas into the container, The gas filling means has a plurality of gas filling modes for injecting the gas into the container, and a control means for switching the gas filling mode at least once to inject the gas into the container. Filling device. 4. The gas filling device according to claim 3, wherein the plurality of gas filling modes are two or more of a constant flow rate mode, a constant flow rate time mode, a constant airflow velocity mode, and a constant wall airflow force mode. A gas filling device characterized by being selected.