The present invention relates to a gas exhaust structure (gas discharge structure) for evacuating gas inside a vacuum chamber, and to an apparatus (a device) and a method for plasma processing.
The following processing apparatus is known as a conventional art (Patent Documents 1, 2). In the processing apparatus, a gas exhaust port is provided in a bottom portion of a vacuum chamber, and a vacuum pump such as a turbo molecular pump is provided directly below the gas exhaust port, so that the atmosphere inside the vacuum chamber is evacuated uniformly and thus uniformity in processing is improved.
A pressure control valve is used between the vacuum chamber and the vacuum pump to control the pressure inside the vacuum chamber. Due to the increase in the diameter of a substrate, a pendulum gate valve is recently used to perform efficient gas evacuation by the turbo molecular pump.
As shown in
In the plasma processing apparatus 30, desired plasma processing is performed on the substrate 33 as follows. The substrate 33 is placed on the placing table 32. A desired gas is supplied into the vacuum chamber 31. The pressure inside the vacuum chamber 31 is controlled by using an unillustrated pressure control device to control an opening ratio of an opening 35a of the pendulum gate valve 35 by means of a valve body 35b. Then, plasma is generated inside the vacuum chamber 31.
Disposing the parts to have the positional relationships described above allows the atmosphere in the vacuum chamber 31 to be uniformly evacuated when the opening 35a of the pendulum gate valve 35 is fully opened. However, when the inside of the vacuum chamber 31 is to be controlled at a desired pressure, the opening 35a will not be fully opened. Generally, the pressure is controlled to be a desired value by closing part of the opening 35a with the valve body 35b to control the opening ratio of the opening 35a. Along with the movement of the circular valve body 35b relative to the circular opening 35a, an opening region M of the opening 35a in the pendulum gate valve 35 changes in a manner similar to a total solar eclipse, and thus causes unevenness in gas evacuation.
For example, when a center value of a recommended usage value of the opening ratio of the pendulum gate valve 35 is 30%, the opening region M has a crescent shape offset to one side of the opening 35a as shown in
Moreover, usage of the pendulum gate valve 35 causes the following problems due to the structure thereof.
The pendulum gate valve 35 is provided with a standby portion 35e of the valve body 35b for the maintenance of the valve body 35b. The valve body 35c is moved to the position of the standby portion 35e (see the dotted line portion in the drawing) by rotating the valve body 35b about a rotation shaft 35c. By removing the standby portion 35e at a flange 35d, the maintenance of the valve body 35b is made possible. Accordingly, it is desirable to dispose the standby portion 35e outward of a side wall of the vacuum chamber 31 from the viewpoint of performing the maintenance. However, the size (diameter) of the vacuum chamber 31 has increased due to recent increase in the diameter of the substrate. There is no need to increase the diameters of the TMP and the opening of the pendulum gate valve if a sufficient gas evacuation performance is obtained. Thus, when the center of the opening 35a of the pendulum gate valve 35 is disposed to coincide with the axis center Cc of the vacuum chamber 31, part of the standby portion 35e is disposed inward of the side wall of the vacuum chamber 31. This causes deterioration in the maintainability. If the diameters of the TMP and the opening of the pendulum gate valve are increased in accordance with the diameter of the vacuum chamber, the heights of the TMP and the pendulum gate valve are increased. Thus, the transport height of the substrate is also required to be increased. Increasing the height of the entire apparatus in accordance with the transport height should be avoided from a view point of ergonomics in handling the substrate.
Moreover, as described above, the standby portion 35e is disposed at a position accessible from the outside. However, among the bolts 36 attaching the pendulum gate valve 35 to the connection member 34, the bolts 36 on the side opposite to the standby portion 35e are located on a deeper side of the processing apparatus. Thus, the fastening and removing of those bolt 36 is difficult.
Furthermore, the pendulum gate valve 35 and the TMP 37 are disposed directly below the vacuum chamber 31. Thus, the roughing line 38 and the valve 39 have to be connected to the side wall of the vacuum chamber 31. This causes deterioration in maintainability and is not efficient in terms of effective utilization of space.
The present invention has been made in view of the problems described above, and an object thereof is to provide a gas exhaust structure and an apparatus and a method for plasma processing which improve the maintainability while allowing uniform gas evacuation.
A gas exhaust structure according to a first invention for solving the above problems is a gas exhaust structure used in a processing apparatus in which a desired gas is supplied into a cylindrical vacuum chamber, a pressure inside the vacuum chamber is controlled by using a pendulum gate valve attached to a lower portion of the vacuum chamber and a vacuum pump attached to a lower portion of the pendulum gate valve, and desired processing is performed on a processing target placed in the vacuum chamber, wherein
the pendulum gate valve is attached to the vacuum chamber in such a manner that a center of an opening of the pendulum gate valve in a state where the opening is fully opened is eccentric to an axis center of the vacuum chamber in an opening direction of a valve body opening and closing the opening of the pendulum gate valve.
A gas exhaust structure according to a second invention for solving the above problems is a gas exhaust structure used in a processing apparatus in which a desired gas is supplied into a cylindrical vacuum chamber, a pressure inside the vacuum chamber is controlled by using a pendulum gate valve attached to a lower portion of the vacuum chamber and a vacuum pump attached to a lower portion of the pendulum gate valve, and desired processing is performed on a processing target placed in the vacuum chamber, wherein
the pendulum gate valve is attached to the vacuum chamber in such a manner that an area center of an opening region at a defined opening ratio of the pendulum gate valve coincides with an axis center of the vacuum chamber, the defined opening ratio is equal to a center value of a recommended usage value of the opening ratio of the pendulum gate valve.
A gas exhaust structure according to a third invention for solving the above problems is the gas exhaust structure according to the first or second invention, wherein a gas exhaust line and a valve leading to another vacuum pump are provided in a lower portion of the vacuum chamber near a lateral side of the pendulum gate valve.
An apparatus for plasma processing according to a fourth invention for solving the above problems is an apparatus for plasma processing which includes a cylindrical vacuum chamber supplied with a desired gas therein, a pendulum gate valve attached to a lower portion of the vacuum chamber, and a vacuum pump attached to a lower portion of the pendulum gate valve, and in which a pressure inside the vacuum chamber is controlled by using the pendulum gate valve and the vacuum pump, plasma of the gas is generated, and plasma processing is performed on a substrate placed in the vacuum chamber, wherein
the pendulum gate valve is attached to the vacuum chamber in such a manner that a center of an opening of the pendulum gate valve in a state where the opening is fully opened is eccentric to an axis center of the vacuum chamber in an opening direction of a valve body opening and closing the opening of the pendulum gate valve.
An apparatus for plasma processing according to a fifth invention for solving the above problems is an apparatus for plasma processing which includes a cylindrical vacuum chamber supplied with a desired gas therein, a pendulum gate valve attached to a lower portion of the vacuum chamber, and a vacuum pump attached to a lower portion of the pendulum gate valve, and in which a pressure inside the vacuum chamber is controlled by using the pendulum gate valve and the vacuum pump, plasma of the gas is generated, and plasma processing is performed on a substrate placed in the vacuum chamber, wherein
the pendulum gate valve is attached to the vacuum chamber in such a manner that an area center of an opening region at a defined opening ratio of the pendulum gate valve coincides with an axis center of the vacuum chamber, the defined opening ratio is equal to a center value of a recommended usage value of the opening ratio of the pendulum gate valve.
An apparatus for plasma processing according to a sixth invention for solving the above problems is the apparatus for plasma processing according to the fourth or fifth invention, wherein a gas exhaust line and a valve leading to another vacuum pump are provided in a lower portion of the vacuum chamber near a lateral side of the pendulum gate valve.
A method for plasma processing according to a seventh invention for solving the above problems is a method for plasma processing using the apparatus for plasma processing according to any one of the fourth to sixth inventions, the method comprising:
supplying gas into the vacuum chamber;
controlling the pressure inside the vacuum chamber by use of the pendulum gate valve and the vacuum pump;
generating the plasma of the gas; and
performing the plasma processing on the substrate placed in the vacuum chamber.
In the first invention, the pendulum gate valve is attached to the vacuum chamber in such an eccentric manner that the center of the opening of the pendulum gate valve in the state where the opening is fully opened is eccentric to the axis center of the vacuum chamber in the opening direction of the valve body. Thus, the flow of gas evacuation in processing is uniform compared to a conventional gas exhaust structure, i.e. the case where the parts are disposed in such a manner that the axis center of the vacuum chamber coincides with the center of the opening of the pendulum gate valve in the state where the opening is fully opened. Moreover, since the pendulum gate valve is eccentrically attached to the vacuum chamber, a standby portion of the pendulum gate valve which is to be removed in maintenance and bolts attaching the pendulum gate valve to the vacuum chamber are disposed more outward than those of the conventional gas exhaust structure. Thus, the maintenance is easy.
In the second invention, the pendulum gate valve is attached to the vacuum chamber in such an eccentric manner that the area center of the opening region at a defined opening ratio of the pendulum gate valve coincides with the axis center of the vacuum chamber. The defined opening ratio is equal to the center value of the recommended usage value of an opening ratio of the pendulum gate valve. Thus, the flow of gas evacuation in processing is uniform compared to the conventional gas exhaust structure. Moreover, since the pendulum gate valve is eccentrically attached to the vacuum chamber, a standby portion of the pendulum gate valve which is to be removed in maintenance and bolts attaching the pendulum gate valve to the vacuum chamber are disposed more outward than those of the conventional gas exhaust structure. Thus, the maintenance is easy.
In the third invention, the gas exhaust line leading to the other vacuum pump is provided in the lower portion of the vacuum chamber near the lateral side of the pendulum gate valve. Thus, the space inside the apparatus for processing is effectively used. In addition, access to the gas exhaust line is easy compared to the conventional gas exhaust structure, and thus the maintainability is improved.
In the fourth to seventh inventions, by applying the gas exhaust structure of any one of the first to third inventions described above to the apparatus and the method for plasma processing, the flow of gas evacuation is made more uniform in a process performed in a degree of vacuum in which the pressure is relatively high, such for example as plasma cleaning. Thus, the plasma cleaning can be performed uniformly without unevenness. Hence, excessive use of gas is reduced, and damage on an inner surface of the chamber by plasma is also reduced.
An example of an embodiment of a gas exhaust structure and an apparatus and a method for plasma processing of the present invention will be described with reference to
As shown in
In the embodiment, the pendulum gate valve 15 is eccentrically attached to the vacuum chamber 11. Specifically, as shown in
If the parts are disposed to have the positional relationships described above, the atmosphere inside the vacuum chamber 31 is evacuated uniformly when the opening ratio of the pendulum gate valve 15 is controlled to be around 30% and the inside of the vacuum chamber 11 is controlled to a desired pressure. When the opening ratio is not around 30% and the inside of the vacuum chamber 11 is controlled to a desire pressure, the gas evacuation is slightly less uniform than when the opening ratio is 30%. Nonetheless, even in such case, the gas evacuation can be made more uniform than the conventional case.
These effects are seen remarkably in processing performed in a degree of vacuum in which a pressure is relatively high. For example, plasma cleaning in a plasma CVD apparatus is performed in a degree of vacuum in which a pressure is a relatively high. Conventionally, the plasma cleaning has been performed unevenly, and there have been a case where excessive gas is consumed to perform certain cleaning and a case where excessive cleaning is performed on some portion thereby causing plasma damage. On the contrary, in the embodiment, uniform plasma cleaning is performed on the vacuum chamber 11 and the placing table 12 by using the gas exhaust structure described above. As a result, damage due to excessive use of gas and plasma is reduced. Hence, it is possible to reduce the frequency of maintenance and extend the lives of the parts.
Moreover, since the pendulum gate valve 15 is eccentrically attached, an opening 14a of the connection member 14 is also eccentrically provided, and the direction of this eccentricity coincides with the opening direction D of the valve body 15b. As a result, a space is made in a portion opposite to the side in which the opening 14a is eccentrically provided. This allows a port 14b for a roughing gas exhaust line 18 to be provided in the lower portion of the vacuum chamber 11 near the lateral side of the pendulum gate valve 15, and allows the roughing gas exhaust line 18, a valve 19, and the like to be disposed directly below the vacuum chamber 11 even if the port is in a side wall of the vacuum chamber 11. In the embodiment, to perform roughing of the inside of the vacuum chamber 11, the roughing line 18 is connected not to the side wall of the vacuum chamber 11 but to the port 14b in a bottom portion of the vacuum chamber 11, and is connected to a roughing vacuum pump 22 through the valve 19 and a gas exhaust line 21. In addition, the gas exhaust line 21 is connected to a gas exhaust port of the TMP 17 through a valve 20. As described above, the roughing line 18, the valve 19, and the like can be disposed directly below the vacuum chamber 11, and be disposed efficiently together with the TMP 17 and the like in an internal space of the processing apparatus.
Furthermore, since the pendulum gate valve 15 is eccentrically connected, a standby portion 15e of the valve body 15b is disposed more outward of the side wall of the vacuum chamber 11 than the conventional processing apparatus. Accordingly, the position of a flange 15d is located more outward, and the standby portion 15e can be easily accessed. Accordingly, the maintenance of the valve body 15b can be performed by rotating the valve body 15b about a rotation shaft 15c to move the valve body 15b to the position of the standby portion 15e. Thus, the maintainability of the pendulum gate valve 15 can be also improved.
The eccentric connection of the pendulum gate valve 15 causes the bolts 16 on the side opposite to the standby portion 15e to be disposed on a closer side than those in the conventional processing apparatus. Thus, difficulty in fastening and removing the bolts 16 can be also reduced.
Note that, in
The present invention is preferably applied to an apparatus and a method for plasma processing such as plasma CVD and plasma etching used to manufacture a semiconductor device. However, the present invention is not limited to the apparatus manufacturing a semiconductor device, and can be also applied to an apparatus manufacturing other products, as long as the apparatus is one which has a gas exhaust port in a lower portion of a vacuum chamber.
Number | Date | Country | Kind |
---|---|---|---|
2009-145196 | Jun 2009 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP2010/058733 | 5/24/2010 | WO | 00 | 2/17/2012 |