JPH0969515A - Vacuum processing system for semiconductor production system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vacuum processing system applicable to vacuum process over a wide pressure range by disposing a displacement regulation valve, along with a pressure regulation valve, on an exhaust pipe coupled with a vacuum chamber and to shorten the total processing time by shortening both the rising time and the exhausting time. SOLUTION: Under a state where the gas on/off valve 21 of a gas supply pipe 12 is closed, an exhaust on/off valve 13 of an exhaust pipe 22 before fully opening a pressure regulation valve 14 and a displacement regulation valve 16. Under maximum flow rate state, an exhaust pump 18 is driven to evacuate a vacuum chamber 11 and discharge the residual gas thus bringing about a specified high vacuum state corresponding to the capacity of exhaust pump. Subsequently, the pressure regulation valve 14 is fully opened and a displacement regulation valve 17 is set at a preset opening before the gas on/off valve 21 is opened to introduce a reaction gas into the vacuum chamber 11. Consequently, the inner pressure of vacuum chamber 11 increases. Since the displacement is restricted by the displacement regulation valve 17 under that state, the rising time is shortened even if a pump having large displacement is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum processing apparatus for semiconductor manufacturing equipment. More specifically, the present invention relates to a vacuum exhaust means for a vacuum chamber used in a vacuum process such as etching or CVD.

[0002]

2. Description of the Related Art A low pressure CVD apparatus, an ion etching apparatus, a vapor deposition apparatus, a sputtering apparatus or the like is used in a film forming process or a lithographic process in a semiconductor manufacturing process. These devices are equipped with a vacuum chamber for performing various kinds of processing on a wafer under vacuum conditions, and a vacuum exhaust unit connected to the vacuum chamber.

FIG. 3 shows a main structure of a conventional vacuum processing apparatus for carrying out such a vacuum process.

A gas supply pipe 2 for introducing a reaction gas is connected to the vacuum chamber 1. This vacuum chamber 1
A wafer (not shown) to be processed by the vacuum process is set therein. A gas opening / closing valve 7 for supplying / cutting off the reaction gas is provided on the gas supply pipe 2. An exhaust pipe 8 connected to an exhaust pump 5 is further connected to the vacuum chamber 1. An exhaust opening / closing valve 3 for opening / closing the exhaust pipe is provided on the exhaust pipe 8, and a pressure adjusting valve 4 for adjusting the pressure in the vacuum chamber 1 is arranged in series with the exhaust opening / closing valve 3. It is provided. The pressure adjusting valve 4 is connected to the controller 6 and its opening is automatically controlled according to the set pressure.

In the vacuum processing apparatus having the above structure, first, the gas on-off valve 7 of the gas supply pipe 2 is closed, the exhaust on-off valve 3 of the exhaust pipe 8 is opened, and the pressure adjusting valve 4 is fully opened (maximum flow rate state). Then, the exhaust pump 5 is driven to evacuate the inside of the vacuum chamber 1 to discharge the residual gas and the like in the vacuum chamber 1 to a predetermined high vacuum state according to the exhaust pump capacity (exhaust amount). Next, the pressure control valve 4 is fully closed (minimum flow rate state), and the gas opening / closing valve 7 is opened to introduce the reaction gas into the vacuum chamber 1. This raises the pressure in the vacuum chamber.

With the vacuum pressure in the vacuum chamber 1 reaching the set value required for the process, the vacuum process is started to process the wafer. This vacuum process is performed under the condition that the exhaust gas is driven while always supplying a constant flow rate of the reaction gas into the chamber, and the required pressure is set according to the balance between the reaction gas supply rate and the exhaust rate. The controller 6 automatically controls the opening degree of the pressure adjusting valve 4 according to the pressure in the vacuum chamber 1 so that the vacuum pressure required for the set vacuum processing process is obtained. That is, the opening degree of the pressure adjustment valve 4 is feedback-controlled with the set vacuum pressure as a target value, and the balance between the flow rate of the reaction gas supplied from the gas supply pipe 2 and the exhaust flow rate according to the opening degree of the pressure adjustment valve 4. Thus, the valve opening is automatically controlled so that the inside of the vacuum chamber 1 is maintained at a predetermined vacuum pressure.

When the wafer vacuum processing process is completed,
The gas on-off valve 7 is closed to stop the supply of the reaction gas, and the pressure adjusting valve 4 is fully opened to purge the inside of the vacuum chamber 1 to discharge the reaction gas remaining in the chamber.
This completes the wafer vacuum processing process.

FIG. 4 is a graph showing the relationship between the valve opening of the pressure control valve 4 and the pressure in the vacuum chamber.
In this pressure control valve, the valve body is in the shape of a butterfly valve, and the opening thereof is within a range of ± several tens of degrees around 45 degrees, which is a stable region where the pressure can be controlled stably. The minimum opening A1 that is the stable control region is set to the fully closed position, the maximum opening A2 is set to the fully open position, and the opening control of the pressure adjusting valve is performed within the range of A1 to A2. If the valve opening is reduced to less than A1, the balance of the exhaust flow rate becomes smaller than the amount of reaction gas flowing into the chamber, and the inside of the chamber becomes high pressure (vacuum pressure weakened), and the valve opening changes slightly. Even if the pressure changes too much, stable control cannot be performed. On the contrary, when the valve opening is opened more than A2, the balance of the exhaust gas flow rate becomes large compared to the inflow amount of the reaction gas into the chamber, and the pressure in the chamber becomes low (the vacuum pressure is intensified).
Even if the valve opening is changed, the pressure hardly changes and control becomes difficult.

Therefore, in order to control the pressure regulating valve in the stable control region, if the gas inflow amount into the vacuum chamber is constant, the usable exhaust pump is an exhaust gas within a predetermined range corresponding to the vacuum pressure to be set. Limited to pumping capacity. That is, when the supply amount of the reaction gas to the vacuum chamber and the set pressure of the vacuum process are determined, the exhaust amount of the exhaust pump that can be stably used is determined. It will not be possible to control within the range of A2).

FIGS. 5A and 5B show the time of the pressure in the vacuum chamber of the vacuum processing apparatus shown in FIG. 3 using a large capacity pump with a large displacement and a small capacity pump with a small displacement, respectively. It is a graph which shows change. The horizontal axis represents the time from the time when the gas on-off valve for introducing the reaction gas was opened, and the vertical axis represents the pressure in the vacuum chamber. In the case of the large displacement pump shown in (A), the pressure rising step until reaching a predetermined set pressure is A1, the wafer processing step at which the set pressure is reached to perform a vacuum processing process is B1, and the vacuum processing is completed and the chamber is completed. The exhaust step for purging the reaction gas in the inside is C1, and the time of A1, B1, and C1 is t1, t
2 and t3, and the total time is represented by t0. Further, in the case of the small displacement pump shown in FIG. 7B, the pressure rising step until reaching a predetermined set pressure is A2, the wafer processing step at which the set pressure is reached to perform the vacuum processing process is B2, and the vacuum processing is completed. C2 is an exhaust step for purging the reaction gas in the chamber by A2, B2, C
Each time of 2 is represented by T1, T2, T3, and the total time is represented by T0. As can be seen from the figure, when the large displacement pump of FIG. (A) is used, the rising time t1 until reaching the set pressure is long and the exhaust time t3 required for gas discharge is short. On the other hand, when the small displacement pump shown in FIG.
1 is short, and the exhaust time T3 required for exhausting gas is long.

[0011]

As described above, in order to use the pressure regulating valve in the opening range of the stable control region, the exhaust pump that can be used according to the set pressure for vacuum processing is limited. Even if an exhaust pump is selected within this limitation to reduce the total processing time, as shown in FIG. 5, there is a trade-off relationship between the rise time to the set pressure and the exhaust time for exhausting the reaction gas. However, either the start-up time or the exhaust time becomes long regardless of whether a pump having a large exhaust capacity or a pump having a small exhaust capacity is used, and the total time cannot be sufficiently shortened.

Further, because of the valve opening characteristic of the pressure regulating valve, the pressure range that can be stably controlled by the same pump is limited. Therefore, in the process of the set pressure exceeding the width of the stable control region, the exhaust pump must be replaced. There must be. Therefore, the work of the vacuum processing process is time-consuming, and the operation becomes troublesome, resulting in a decrease in throughput.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and expands the range of the stable control region to expand the range of vacuum pressure that can be covered by one exhaust pump, and the vacuum process in a wide pressure range. It is an object of the present invention to provide a vacuum processing apparatus for a semiconductor manufacturing apparatus that is applicable to the above, and that shortens both the rise time and the exhaust time to shorten the total processing time.

[0014]

In order to achieve the above object, in the present invention, a vacuum chamber for processing a semiconductor wafer at a predetermined vacuum pressure set for each process,
A gas supply pipe for introducing a reaction gas connected to the vacuum chamber, a gas on-off valve provided on the gas supply pipe, and an exhaust pump for vacuum exhaust connected to the vacuum chamber via an exhaust pipe. An exhaust opening / closing valve provided on the exhaust pipe,
Vacuum processing for a semiconductor manufacturing apparatus having a pressure adjusting valve provided on the exhaust pipe in series with the exhaust opening / closing valve, and control means for controlling the opening degree of the pressure adjusting valve according to the predetermined vacuum pressure. In the apparatus, there is provided a vacuum processing apparatus for a semiconductor manufacturing apparatus, wherein an exhaust amount adjusting valve is provided on the exhaust pipe.

In a preferred embodiment, the displacement control valve is connected to the control means, and the control means controls the pressure control valve according to the vacuum pressure of the vacuum chamber with the predetermined vacuum pressure as a target value. The opening degree is controlled, and the opening degree of the exhaust amount adjusting valve is set so that the opening degree of the pressure adjusting valve falls within a predetermined stable control range.

In another preferred embodiment, each exhaust pipe of the plurality of vacuum chambers is connected to a common exhaust pump,
The exhaust opening / closing valve, the pressure adjusting valve, and the exhaust amount adjusting valve are provided on each exhaust pipe to form a vacuum exhaust system for a semiconductor manufacturing apparatus.

[0017]

Function: First, the inside of the vacuum chamber is evacuated, and then a reaction gas is introduced into the vacuum chamber to raise the vacuum pressure to a set pressure. At the time of startup, the exhaust amount is reduced by throttling the exhaust amount adjusting valve, which is substantially the same as the use of an exhaust pump having a small capacity. This shortens the time required to start up to the required vacuum pressure. When purging the inside of the chamber after completion of the vacuum treatment, the exhaust amount adjusting valve is fully opened together with the pressure adjusting valve, which is substantially the same as using an exhaust pump having a large capacity. This reduces the exhaust time.

That is, by providing an exhaust amount adjusting valve on an exhaust pipe connected to a pump having a large exhaust amount, the exhaust amount adjusting valve is throttled at the time of rising to a set pressure to substantially reduce the exhaust capacity, As shown in FIG. 5B, the startup characteristic of the small capacity pump is obtained. On the other hand, when exhausting, the exhaust amount adjusting valve is fully opened to obtain the exhaust characteristic of the large capacity pump as shown in FIG. As a result, both pump characteristics are combined to shorten the startup time and the exhaust time.

When the pressure control valve is controlled so that the valve opening is within the stable control range, the pressure control valve is conventionally fully closed (A1 in FIG. 4) or fully opened (A in FIG. 4), which is the limit position of pressure control.
Even at the position of 2), the pressure can be adjusted by further adjusting the opening of the exhaust amount adjusting valve, and the pressure adjusting range in the stable control region is expanded.

As described above, since the stable control area can be expanded, a large displacement pump can be used to control the pressure of a small displacement which could not be achieved in the past, and one exhaust having the same displacement can be used. The pressure range of the vacuum processing process that can be performed by the pump is expanded, which increases the usability of the vacuum processing apparatus and enables the process to be performed efficiently.

Further, since the usable area of the exhaust pump is expanded as described above only by mounting the exhaust amount adjusting valve on the exhaust pipe of the existing device, the same effect as replacing the exhaust pump can be obtained.

Furthermore, an efficient vacuum processing system can be constructed by connecting a plurality of vacuum chambers to one large exhaust pump and providing an exhaust amount adjusting valve on each exhaust pipe. Therefore, productivity can be improved.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of the essential parts of an embodiment of a vacuum device for semiconductor production according to the present invention.

Inside the vacuum chamber 11, there is provided a wafer holder 11a having a fixing means (not shown) such as a vacuum chuck type or an electrostatic chuck type for setting the wafer 20 to be processed by a vacuum process. A gas supply port 11c for introducing a reaction gas necessary for a vacuum process treatment such as etching or sputtering is attached to the upper part of the vacuum chamber 11, and a gas supply pipe 12 is connected to the gas supply port 11c. A gas on-off valve 21 for supplying / cutting off the reaction gas is provided in the middle of the gas supply pipe 12. An exhaust port 11b is provided at the bottom of the vacuum chamber 11.
An exhaust pipe 22 connected to the exhaust pump 18 is attached to the exhaust port 11b. Exhaust pipe 22
Is provided with an exhaust opening / closing valve 13 for opening / closing the exhaust pipe, and a pressure adjusting valve 14 for adjusting the pressure in the vacuum chamber 11 is provided in the exhaust opening / closing valve 1.
3 in series. Further, an exhaust amount adjusting valve 17 for adjusting the exhaust amount is provided between the pressure adjusting valve 14 on the exhaust pipe 22 and the exhaust pump 18. Pressure control valve 14
And the displacement control valve 17 are respectively the valve controller 16
The valve opening is automatically controlled according to the set pressure. The valve controller 16 is the process front roller 1.
Connected to 5. The process controller 15 has a program for controlling the sequence of the whole process,
According to this program, data of vacuum pressure conditions for vacuum processing (or valve opening degree data calculated based on the data) is sent to the valve controller 16. Based on this information, the valve controller 16 drives a servo motor or the like (not shown) to automatically control the valve opening so that the valve opening becomes a proper pressure.

The vacuum processing process in the vacuum processing apparatus having the above structure is performed as follows. First, the gas supply pipe 1
With the gas on-off valve 21 of No. 2 closed, the exhaust on-off valve 13 of the exhaust pipe 12 is opened, and the pressure adjusting valve 14 and the exhaust amount adjusting valve 16
Fully open. In this case, when the pressure adjusting valve 14 and the exhaust amount adjusting valve 17 are fully opened, the range of the valve opening is 45 in advance.
The maximum flow rate is within this range because it is set to ± 10 degrees (the above-mentioned stable control region). In this state, the exhaust pump 18 is driven to evacuate the inside of the vacuum chamber 11 to discharge residual gas and the like inside, and a predetermined high vacuum state according to the exhaust pump capacity (exhaust volume) is established.

Next, the pressure adjusting valve 14 is fully closed (minimum flow rate state), the exhaust amount adjusting valve 17 is set to a preset opening degree, the gas opening / closing valve 21 is opened, and the reaction gas is placed in the vacuum chamber 11. To introduce. As a result, the pressure in the vacuum chamber 11 rises (pressure rising state). In this state, since the exhaust amount is throttled by the exhaust amount adjusting valve 17, even if a pump with a large exhaust amount is used, it becomes similar to the case with an exhaust pump with a small exhaust amount, and the rise time is shortened. At this time, the reason why the pressure adjusting valve 14 is fully closed is
This is because the exhaust flow rate is reduced to the minimum and the rise time is shortened as much as possible. In this case, the exhaust amount adjusting valve 17 may also be configured to have a minimum opening so as to shorten the pressure rise time and return to the set opening when a predetermined pressure is reached. With the vacuum pressure in the vacuum chamber 11 reaching a set value required for the process, vacuum processing such as wafer etching or sputter film formation is performed. This vacuum process is performed in a state where the exhaust gas pump 18 is driven while always supplying a fixed amount of reaction gas into the vacuum chamber 11 to set a required pressure by the balance between the reaction gas supply amount and the exhaust amount. . The valve controller 16 reads the valve opening signal of the pressure regulating valve 14 preset by the process controller 15 and the pressure signal obtained by detecting the current pressure in the vacuum chamber with the vacuum gauge 19, and determines the vacuum pressure required for the vacuum process. The opening degree of the pressure adjusting valve 14 is controlled so that That is, the opening degree of the pressure adjusting valve 14 is feedback-controlled with the set vacuum pressure as a target value, and is adjusted by the balance between the reaction gas amount supplied from the gas supply pipe 12 and the exhaust amount according to the opening degree of the pressure adjusting valve 14. The valve opening is automatically controlled so that the inside of the vacuum chamber 11 is maintained at a predetermined vacuum pressure. At this time, the opening degree of the pressure regulating valve 14 is always within the above-mentioned stable control range,
The exhaust amount of the exhaust pump 18 is throttled by setting the exhaust amount adjusting valve 17 to a constant opening degree according to the process pressure.

When the wafer vacuum processing process is completed,
The gas on-off valve 21 is closed to stop the supply of the reaction gas, and the pressure regulating valve 14 and the exhaust amount control valve 17 are fully opened to purge the inside of the vacuum chamber and discharge the reaction gas remaining in the chamber. This completes the wafer vacuum processing process.

FIG. 2 is a graph showing the pressure change in the vacuum chamber of the vacuum processing apparatus according to the above embodiment. Similar to the graph shown in FIG. 5, the horizontal axis represents the time from the time when the gas on-off valve for introducing the reaction gas was opened, and the vertical axis represents the pressure in the vacuum chamber. Solid lines A, B, and C respectively indicate the pressure rise time portion, the wafer processing time portion, and the exhaust time portion in this embodiment. As described above, in this embodiment, by narrowing the exhaust amount adjusting valve 17,
The pressure rise portion A can be shortened in the same manner as the rise time portion A2 of the small capacity pump of FIG. 5 (B) to reach the required pressure in a short time (T1). The broken line in the figure shows the case of the large-capacity pump of FIG. 5 (A), and shows the startup time A1 when the exhaust amount adjusting valve 17 of this embodiment is not provided.

In the exhaust time portion C of this embodiment, the exhaust capacity adjusting valve 17 is fully opened so that the exhaust capacity is fully utilized and the large capacity pump shown in FIG. 5 (A) is used. Shorten the exhaust time portion C1 to shorten the time (t
In 3), the chamber can be evacuated. In the figure, the alternate long and short dash line shows the case of the small capacity pump of FIG. 5B, and shows the exhaust time C2 when the large capacity pump cannot be used as in this embodiment. As can be seen from the above graphs, in the present embodiment, with respect to the start-up part and the exhaust part of the large capacity pump and the small capacity pump shown in FIGS. The total processing time can be shortened by combining it with the short startup time of the small capacity pump.

In the above embodiment, according to the pressure required for the process, it is possible to use a pump having a large displacement so that the valve opening degree is out of the stable control range. Therefore, by providing the exhaust amount adjusting valve of the above-mentioned embodiment on the exhaust pipe connected to the existing large displacement pump, it becomes possible to carry out the process which was conventionally possible only with the small displacement pump. When using the same pump as before,
By controlling the opening of the displacement control valve, the width of the stable control region can be widened, and highly accurate pressure control can be performed in a wide flow rate range. Further, since it is possible to carry out processes having greatly different set pressures using the same large capacity pump, it is possible to form a vacuum processing system of a unified system by connecting a plurality of chambers to a common exhaust pump. The vacuum processing apparatus according to the above embodiment is applicable to a sputtering apparatus, an ion etching apparatus, a vapor deposition apparatus, a low pressure CVD apparatus, an ion implantation apparatus, and other apparatuses for processing a wafer under vacuum conditions, which are related to semiconductor manufacturing.

[0032]

As described above, according to the present invention, the controllable range of the exhaust pump capacity is increased by the simple structure in which the pressure adjusting valve and the exhaust amount adjusting valve are provided on the exhaust pipe connected to the vacuum chamber. spread. Therefore,
When raising the pressure at the start of the process with a large displacement pump, the displacement is reduced by throttling the displacement control valve, and the required vacuum pressure is substantially the same as when using an exhaust pump with a small capacity. Startup time can be shortened, and when purging the inside of the chamber after the vacuum processing is completed, the exhaust volume adjustment valve is fully opened together with the pressure adjustment valve, and the exhaust pump capacity of large exhaust volume is fully used Can be shortened.

Further, by adjusting the opening of the exhaust amount adjusting valve, the opening range of the pressure adjusting valve in the stable control region is expanded and the pressure adjusting range is expanded. Therefore, the pressure range of the vacuum processing process that can be performed by one exhaust pump with the same exhaust amount is expanded, which increases the usability of the vacuum processing apparatus and enables the process to be performed efficiently. Is improved.

Further, since the usable area of the exhaust pump is expanded as described above just by mounting the exhaust amount adjusting valve on the exhaust pipe of the existing apparatus, the cost and the labor are not required, and it is substantially the same as the replacement of the exhaust pump. The effect is obtained.

Further, an efficient vacuum processing system can be constructed by connecting a plurality of vacuum chambers to one large exhaust pump and providing an exhaust amount adjusting valve on each exhaust pipe. Therefore, productivity can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vacuum processing apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory graph showing the relationship between time and pressure in the vacuum chamber of the embodiment of FIG.

FIG. 3 is a configuration diagram of a main part of a conventional vacuum processing apparatus.

FIG. 4 is an opening characteristic graph of the pressure regulating valve used in the present invention.

FIG. 5 is an explanatory graph showing the relationship between time and pressure in a vacuum chamber of a conventional vacuum processing apparatus, where (A) shows the case of using a large capacity pump and (B) shows the case of using a small capacity pump. ing.

[Explanation of symbols]

11: vacuum chamber, 12: gas supply pipe, 13: exhaust opening / closing valve, 14: pressure adjusting valve, 15: process controller, 16: valve controller, 17: exhaust amount adjusting valve,
18: Exhaust pump, 19: Vacuum gauge, 20: Wafer, 2
1: Gas on-off valve, 22: Exhaust pipe.

Claims (3)

[Claims] 1. A vacuum chamber for processing a semiconductor wafer at a predetermined vacuum pressure set for each process, a gas supply pipe for introducing a reaction gas connected to the vacuum chamber, and a gas supply pipe on the gas supply pipe. A gas on-off valve provided, an exhaust pump for vacuum exhaust connected to the vacuum chamber via an exhaust pipe, an exhaust on-off valve provided on the exhaust pipe, and the exhaust pipe in series with the exhaust on-off valve. A vacuum processing apparatus for a semiconductor manufacturing apparatus, comprising: a pressure adjusting valve provided above; and a control means for controlling the opening of the pressure adjusting valve according to the predetermined vacuum pressure. A vacuum processing apparatus for a semiconductor manufacturing apparatus, which is provided with a regulating valve. 2. The displacement control valve is connected to the control means, and the control means controls the opening of the pressure control valve according to the vacuum pressure of the vacuum chamber with the predetermined vacuum pressure as a target value. The opening degree of the exhaust amount adjusting valve is set so that the opening degree of the pressure adjusting valve falls within a predetermined stable control range. Vacuum processing equipment for semiconductor manufacturing. 3. The exhaust pipes of a plurality of vacuum chambers are connected to a common exhaust pump, and the exhaust on-off valves are provided on the respective exhaust pipes.
A vacuum exhaust system for a semiconductor manufacturing apparatus using a vacuum processing apparatus according to claim 2, further comprising a pressure adjusting valve and an exhaust amount adjusting valve.