JP2010027836A - Plasma treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment apparatus which allow abnormalities in the exhaust capability of a vacuum pump and in a vacuum piping system to be easily monitored online for appropriately monitoring the operating state of the apparatus. <P>SOLUTION: A plasma treatment apparatus 1 that performs plasma treatment on a substrate 8 in a treatment chamber 3a is provided with a second vacuum sensor 17, which is provided between a vacuum pump 14 and a vacuum valve 13 that connects/disconnects the treatment chamber 3a to/from the vacuum pump 14 in an exhaust piping system 12, in addition to a first vacuum sensor 15 which measures an attainable vacuum in the treatment chamber 3a. On the basis of a measuring result obtained by the second vacuum sensor 17 with the vacuum valve 13 closed, abnormalities in the exhaust capability of the vacuum pump 14 and abnormalities in a vacuum exhaust pipe 12b, such as a vacuum leak, are detected by a control section 22. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus that performs plasma processing in a reduced-pressure atmosphere on an object to be processed such as a substrate placed in a sealed processing chamber.

  In the field of manufacturing electronic devices, plasma treatment is widely used for the purpose of cleaning and surface modification of a substrate on which electronic components are mounted. In this method, plasma is generated in a sealed space with a reduced pressure atmosphere, and the surface treatment of the surface to be treated is performed by the physical action or chemical action of the plasma. In order to form a reduced pressure atmosphere in this method, a vacuum chamber for forming a sealed processing chamber and a vacuum exhaust means for evacuating the processing chamber are required. Then, the vacuum chamber is opened and closed for each cycle of plasma cleaning, and electronic components are taken in and out. After the vacuum chamber is closed, each time the vacuum is exhausted until the processing chamber reaches a predetermined vacuum level. The time required for this evacuation occupies a considerable part of the cycle time of one cycle of plasma cleaning.

  In this plasma treatment, electrons and ions collide with the surface of the object to be treated, and the surface contaminants are removed by the etching effect. Therefore, the removed particulate contaminants are scattered around and are enclosed in a sealed space. Adheres to the inner wall of the vacuum chamber. When this contaminant adheres to and accumulates on the inner surface of the vacuum chamber, the deposited layer adsorbs atmospheric water vapor and other gases introduced from the outside each time the vacuum chamber is opened and closed. These gases are released from the deposition layer when the vacuum chamber is evacuated and increase the time required for evacuation. Therefore, it is necessary to prevent such adhesion and deposition of contaminants as much as possible.

For this reason, as a plasma processing apparatus conventionally, a shield member for preventing such adhesion is attached to the inner surface of the vacuum chamber, and the degree of vacuum in the processing chamber is measured by a vacuum sensor, resulting in contamination. There has been known one having a function of monitoring a delay of the evacuation time to automatically indicate a proper maintenance time (see Patent Document 1).
Japanese Patent Laid-Open No. 11-54487

  However, the above prior art examples have the following disadvantages. That is, the delay of the evacuation time is greatly influenced not only by the contamination of the inner surface of the vacuum chamber constituting the processing chamber but also by abnormalities such as contamination of the vacuum pump itself, which is the evacuation source, and leakage in the vacuum piping system. However, in the conventional plasma processing apparatus, the vacuum sensor is arranged in communication with the processing chamber because the main purpose is to monitor the ultimate vacuum in the plasma processing process, and the exhaust capacity associated with the contamination of the vacuum pump itself. It is not possible to identify and detect a drop in the air pressure or a leak in the vacuum piping system. For this reason, in order to detect an abnormality in the exhaust capability of the vacuum pump itself or the vacuum piping system, it is necessary to stop the operation of the apparatus and perform a dedicated test separately, which is one of the factors that lower the apparatus operation rate. It was one. As described above, in the conventional plasma processing apparatus, there is a problem that it is difficult to easily monitor the exhaust capacity of the vacuum pump and the abnormality of the vacuum piping system in order to properly monitor the operation state of the apparatus in an on-line state. .

  Therefore, an object of the present invention is to provide a plasma processing apparatus that can easily monitor in an online state an exhaust capability of a vacuum pump and an abnormality of a vacuum piping system for properly monitoring the operating state of the apparatus.

  The plasma processing apparatus of the present invention is a plasma processing apparatus that performs plasma processing in a reduced-pressure atmosphere on an object to be processed that is placed in a sealed processing chamber, the vacuum chamber forming the processing chamber, and the vacuum An electrode portion provided in the chamber on which the workpiece is placed, a vacuum pump connected to the processing chamber via a vacuum exhaust pipe and exhausting the processing chamber, and a processing chamber provided in the vacuum exhaust pipe A vacuum valve that connects and disconnects the vacuum pump, a gas supply unit that supplies a gas for generating plasma into the processing chamber, a high-frequency power supply unit that applies a high-frequency voltage to the electrode unit, and a communication chamber that communicates with the processing chamber A first vacuum degree measurement unit, and a second vacuum degree measurement unit provided between the vacuum valve and the vacuum pump in the vacuum exhaust pipe, The ultimate vacuum in the processing chamber is measured based on the measurement result, and the vacuum pump and / or the vacuum exhaust pipe is measured based on the measurement result of the second vacuum measurement unit with the vacuum valve closed. Detect the presence or absence of abnormalities.

  According to the present invention, in addition to the first degree-of-vacuum measurement unit that measures the ultimate degree of vacuum inside the processing chamber, the second is provided between the vacuum valve and the vacuum pump that connect and disconnect the processing chamber and the vacuum pump in the vacuum exhaust pipe. By providing the vacuum degree measuring unit 2, it is possible to detect whether there is an abnormality in the vacuum pump or the vacuum exhaust pipe based on the measurement result of the second vacuum degree measuring unit with the vacuum valve closed, The pumping capacity of the vacuum pump and the abnormality of the vacuum piping system for appropriately monitoring the operating state of the apparatus can be easily monitored in an on-line state.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a plasma processing apparatus according to an embodiment of the present invention, FIG. 2 is a flowchart of plasma processing operation in the plasma processing apparatus according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a graph showing the change in ultimate vacuum over time in the plasma processing apparatus of one embodiment of the present invention.

  First, the configuration of the plasma processing apparatus 1 will be described with reference to FIG. The plasma processing apparatus 1 has a function of performing plasma processing for the purpose of plasma cleaning, surface modification, and the like in a reduced-pressure atmosphere for a substrate that is an object to be processed placed in a sealed processing chamber. . In FIG. 1, a vacuum chamber 3 for forming a processing chamber 3 a for plasma processing is provided on the upper surface side of the flat base portion 2. The vacuum chamber 3 has a configuration in which a box-shaped lid member 4 having an open bottom is disposed so as to be movable up and down with respect to the base portion 2 by an opening / closing mechanism (not shown).

  The base 2 is provided with an opening 2a for mounting an electrode, and an electrode body 5 made of a conductor such as aluminum is mounted on the opening 2a via an insulating member 6. On the outside of the opening 2 a of the base portion 2, the seal member 10 is mounted in an arrangement corresponding to the shape of the lower end portion of the lid member 4. By lowering the lid member 4 and bringing the lower end portion into contact with the seal member 10 provided on the base portion 2, a sealed processing chamber 3 a is formed below the lid member 4.

  The upper surface of the electrode body 5 is covered with an insulating plate 7 made of an insulator such as ceramics, and a substrate 8 to be plasma-treated is placed on the insulating plate 7. That is, the electrode main body 5 and the insulating plate 7 are electrode portions that are provided in the vacuum chamber 3 and on which a substrate 8 that is an object to be processed is placed. A guide member 9 for guiding the conveyance of the substrate 8 is disposed on the upper surface of the insulating plate 7 in the substrate conveyance direction (arrow a direction). A guide member 9 a is disposed on the upper surface of the base portion 2 in a direction aligned with the guide member 9 except for a position where it interferes with the lower end portion of the lid member 4.

  The substrate 8 supplied from the upstream side (left side in FIG. 1) is pushed downstream by the substrate transport mechanism 11 and moves downstream, and is carried into the processing chamber 3a along the guide members 9a and 9. . With the substrate 8 placed on the insulating plate 7, a plasma discharge is generated in the processing chamber 3a, so that the substrate 8 carried on the insulating plate 7 is subjected to cleaning or surface cleaning. Plasma treatment for the purpose of modification is performed. The substrate 8 after the plasma processing is similarly guided by the guide members 9 and 9 a and is carried out by the substrate transport mechanism 11.

  The base 2 is provided with an exhaust hole 2b and a gas supply hole 2c that open in the processing chamber 3a. A first vacuum exhaust pipe 12a that constitutes an exhaust pipe system 12 is connected to the exhaust opening 2b, and a vacuum valve 13 and a second vacuum exhaust pipe 12b are further connected to the first vacuum exhaust pipe 12a. The vacuum pump 14 is connected via The operations of the vacuum valve 13 and the vacuum pump 14 are controlled by the control unit 22. By operating the vacuum pump 14 in a state where the lid member 4 is lowered and the processing chamber 3a is sealed, the inside of the processing chamber 3a is evacuated and a reduced pressure atmosphere is formed. That is, the vacuum pump 14 is connected to the processing chamber 3a via the exhaust piping system 12 including the first vacuum exhaust piping 12a and the second vacuum exhaust piping 12b, and exhausts the processing chamber 3a. The vacuum valve 13 is provided in the second vacuum exhaust pipe 12b and has a function of connecting and disconnecting the processing chamber 3a and the vacuum pump 14.

  A first vacuum sensor 15 and a vent valve 16 are connected to the first vacuum exhaust pipe 12a, and a second vacuum sensor 17 is connected to the second vacuum exhaust pipe 12b. The first vacuum sensor 15 communicates with the processing chamber 3a via the first vacuum exhaust pipe 12a, and the first vacuum sensor 15 communicates with the processing chamber 3a. It has become. Based on the detection result of the first vacuum sensor 15, the ultimate vacuum inside the processing chamber 3 a is measured, and this measurement result is transmitted to the control unit 22. In the plasma processing process, this measurement result is used as a feedback value for maintaining the degree of vacuum in the processing chamber 3a at a preset process pressure, and determines whether maintenance such as internal cleaning of the vacuum chamber 3 is necessary. It is also used as determination data for the purpose.

  By opening the vent valve 16 in a reduced pressure state where the inside of the processing chamber 3a is evacuated, the atmosphere is introduced into the processing chamber 3a via the first evacuation pipe 12a. As a result, the vacuum in the processing chamber 3a is broken, and the lid member 4 can be raised to open the vacuum chamber 3. The second vacuum sensor 17 detects the degree of vacuum in the second vacuum exhaust pipe 12 b in a state where the vacuum valve 13 is closed, and the detection result is transmitted to the control unit 22. Thereby, it is possible to detect the presence or absence of an abnormality in the vacuum exhaust system such as an abnormality in the vacuum exhaust capability of the vacuum pump 14 or a vacuum leak in the second vacuum exhaust pipe 12b. That is, the second vacuum sensor 17 is a second vacuum degree measurement unit provided between the vacuum valve 13 and the vacuum pump 14 in the second vacuum exhaust pipe 12 b of the exhaust pipe system 12. Then, based on the measurement result of the second vacuum sensor 17 with the vacuum valve 13 closed, the control unit 22 determines whether there is an abnormality in the exhaust capability of the vacuum pump 14 and the vacuum leak in the second vacuum exhaust pipe 12b. Detects whether there is an abnormality in the vacuum exhaust system, such as the presence or absence.

A gas supply unit 20 that supplies a gas for generating plasma into the processing chamber 3 a is connected to the gas supply hole 2 c through a gas supply pipe 18 and a gas valve 19. The gas valve 19 and the gas supply unit 20 are controlled by the control unit 22, and by opening the gas valve 19, argon gas, oxygen gas, fluorine gas, or the like is added to the processing chamber 3 a by the gas supply unit 20 according to the plasma processing target. Different types of plasma generating gas are supplied. A high frequency power supply unit 21 controlled by the control unit 22 is electrically connected to the electrode body unit 5. By driving the high frequency power supply unit 21, a high frequency voltage is applied to the electrode main body unit 5, whereby the processing chamber 3.
Plasma discharge occurs in a.

  Next, the plasma processing operation by the plasma processing apparatus 1 will be described with reference to FIG. 3 in accordance with the flow of FIG. When the plasma processing operation is started, a substrate transfer operation is first executed (ST1). That is, with the lid member 4 raised (arrow b) and the vacuum chamber 3 opened, as shown in FIG. 3A, the rear end portion of the substrate 8 supplied from the upstream side is connected to the substrate transport mechanism 11. The substrate 8 is conveyed along the guide member 9a (arrow c). The substrate 8 further moves while being guided by the guide member 9, is carried onto the upper surface of the insulating plate 7 on the electrode main body 5, and is held at a predetermined position. Thereafter, when the substrate transport mechanism 11 is retracted from below the lid member 4 (arrow e), the lid member 4 is lowered (arrow d) to close the vacuum chamber 3 as shown in FIG. ST2).

  Thereafter, the vent valve 16 is closed (ST3), the vacuum valve 13 is then opened (ST4), and the vacuum pump 14 is evacuated through the exhaust piping system 12 (arrow f). Thereby, the inside of the processing chamber 3a is depressurized to a predetermined process pressure suitable for the plasma processing. Next, the gas valve 19 is opened (ST5), and a gas for generating plasma is supplied into the processing chamber 3a through the gas supply pipe 18 by the gas supply unit 20 (arrow g).

  Next, by driving the high-frequency power supply unit 21 in this state, plasma discharge is started in the processing chamber 3a (ST6), and plasma processing for the substrate 8 placed on the insulating plate 7 is executed. When a predetermined processing time has elapsed, the plasma discharge in the processing chamber 3a is terminated (ST7). Thereafter, the gas valve 19 is closed (ST8), the supply of the plasma generating gas into the processing chamber 3a is stopped, the vacuum valve 13 is then closed (ST9), and the vacuum exhaust by the vacuum pump 14 is stopped.

  Then, the vent valve 16 is opened (ST10), the atmosphere is introduced into the processing chamber 3a and the vacuum is broken, and then the lid member 4 is raised (arrow h) as shown in FIG. The chamber 3 is opened (ST11). Next, the substrate 8 that has been processed in this state is pushed along the guide member 9a by the substrate transport mechanism 11 (arrow j), and is carried downstream. As a result, one cycle of the plasma processing for one substrate 8 is completed, and thereafter, the process returns to (ST1), and the same work steps for the subsequent substrate 8 are repeatedly executed.

  In the process in which the above-described work flow is executed, the ultimate vacuum in the processing chamber 3a matches a predetermined process pressure, or the processing chamber 3a, the vacuum pump 14, the exhaust piping system 12, and the like are normal. A process of determining whether or not there is based on the measurement result of the degree of vacuum by the first vacuum sensor 15 and the second vacuum sensor 17 is executed by the control unit 22. FIG. 3 is a graph showing changes over time in the measured values of the first vacuum sensor 15 and the second vacuum sensor 17 in these determination processes, and the curves C1 and C2 are measured by the first vacuum sensor 15. C3 indicates a value measured by the second vacuum sensor 17, respectively.

  A curve C1 shows a change with time of the degree of vacuum in the processing chamber 3a obtained every time the plasma processing process shown in FIG. 2 is executed. That is, when the vacuum valve 13 is opened at (ST4) in FIG. 2 and the inside of the processing chamber 3a is evacuated by the vacuum pump 14, the measured value of the first vacuum sensor 15 corresponds to the atmospheric pressure. It gradually decreases from the pressure value Pa. After reaching a predetermined process pressure Pp (here, a pressure level of about 10 [Pa]), after a temporary pressure increase (arrow k) due to the plasma generating gas being supplied into the processing chamber 3a, It converges again to the process pressure Pp. In the process in which the plasma processing is continued, the measurement value detected by the first vacuum sensor 15 is fed back to the control unit 22 so that the pressure in the processing chamber 3a is maintained at a predetermined process pressure Pp. .

  A curve C2 represents a change with time of the degree of vacuum in the processing chamber 3a acquired during the maintenance determination exhausting operation for determining whether or not the vacuum chamber 3 needs to be maintained. In other words, in the process of repeatedly performing the plasma processing, foreign matter or the like removed from the object to be processed adheres and accumulates inside the vacuum chamber 3 such as the inner wall surface of the lid member 4. Then, the moisture and organic gas adsorbed and trapped by these deposits are released during evacuation, so that the evacuation efficiency in the vacuum chamber 3 is lowered.

  In order to prevent such a reduction in vacuum exhaust efficiency, it is necessary to perform maintenance processing such as cleaning at an appropriate interval for the inside of the vacuum chamber 3. In the example shown here, the target set value of the ultimate vacuum in the processing chamber 3a is set to a target ultimate pressure Pv (here, a pressure level of about 1 [Pa]) corresponding to a vacuum higher than the process pressure Pp. Then, the inside of the processing chamber 3 a is evacuated by the vacuum pump 14.

  Then, when a first determination time T1 preset as an exhaust trial time necessary and sufficient for confirmation of the exhaust capacity has passed, a measured value by the first vacuum sensor 15 becomes a preset maintenance determination pressure Pm. It is determined whether or not it exceeds. That is, when the measured value exceeds the maintenance determination pressure Pm at the time when the first determination time T1 has elapsed, it is determined that the vacuum exhaust efficiency is reduced due to contamination in the vacuum chamber 3, and the vacuum chamber 3 An instruction to the effect that maintenance is required is notified by a notification means (not shown) such as an alarm or display.

  A curve C3 shows a change with time of the degree of vacuum in the second evacuation pipe 12b acquired at the time of the evacuation capacity confirmation operation. This evacuation capacity confirmation operation is executed to confirm the evacuation capacity of the vacuum pump 14 and the presence or absence of a vacuum leak in the second evacuation pipe 12b. The vacuum pump 13 is closed and the vacuum pump 14 is operated. This is performed by acquiring the degree of vacuum in the second evacuation pipe 12b in a state over time. That is, in the process of repeatedly performing the plasma processing, the vacuum pump 14 that evacuates the inside of the processing chamber 3a is not only a normal gas such as a plasma generating gas but also foreign matters such as fine particles removed from the object to be processed and moisture. Etc. are sucked at the same time. These foreign substances adhere and accumulate inside the vacuum pump 14, so that the exhaust capability of the vacuum pump 14 itself is reduced, leading to problems such as a delay in the vacuum exhaust time. Further, when there is a problem such as a vacuum leak in the second vacuum exhaust pipe 12b to which the vacuum pump 14 is connected, even if the vacuum pump 14 has a normal exhaust capability, the delay of the vacuum exhaust time is similarly performed. Occurs.

  In order to prevent such problems, the pumping capacity of the vacuum pump 14 and the piping system problems in the second vacuum exhaust pipe 12b are correctly confirmed, and maintenance such as overhaul of the vacuum pump 14 and replacement of piping parts is performed. It is necessary to execute in a timely manner. In the plasma processing apparatus shown in the present embodiment, the presence or absence of such a defect is detected by the measurement result of the second vacuum sensor 17 provided in the second vacuum exhaust pipe 12b. That is, the vacuum valve 13 is closed and the second vacuum exhaust pipe 12b is completely closed at a timing when it is not necessary to perform vacuum exhaust in the processing chamber 3a (for example, during the substrate transfer operation in (ST1) shown in FIG. 2). Then, the target set value of the ultimate vacuum is set to the aforementioned target ultimate pressure Pv, and the inside of the second vacuum exhaust pipe 12b is evacuated by the vacuum pump 14.

Then, when a predetermined second determination time T2 has elapsed, it is determined whether or not the measured value by the second vacuum sensor 17 exceeds a preset maintenance determination pressure Pm. Since the internal volume of the second vacuum exhaust pipe 12b is small and the vacuum exhaust is completed quickly, the second determination time T2 can be set to a time significantly shorter than the first determination time T1. When the measured value exceeds the maintenance determination pressure Pm at the time when the second determination time T2 set in this way has elapsed, the exhaust capacity itself of the vacuum pump 14 is reduced or the second vacuum exhaust pipe 12b is vacuumed. It is determined that some trouble has occurred in the vacuum exhaust system, such as a situation where there is a leak or both, and this is notified by a notification means such as an alarm or display.

  That is, in the present embodiment, the presence or absence of abnormality in the vacuum pump 14 and / or the second vacuum exhaust pipe 12b is detected based on the measurement result of the second vacuum sensor 17 with the vacuum valve 13 closed. The maintenance determination pressure Pm used here may be the same as the maintenance determination pressure Pm when the above-described determination of necessity of maintenance of the vacuum chamber 3 is targeted, or a dedicated maintenance determination pressure Pm. Each may be set individually.

  As described above, in the plasma processing apparatus 1 shown in the present embodiment, in addition to the first vacuum sensor 15 that measures the ultimate vacuum inside the processing chamber 3a, the processing chamber 3a and the vacuum pump are provided in the exhaust piping system 12. A second vacuum sensor 17 is provided between the vacuum valve 13 and the vacuum pump 14 that connect and disconnect the circuit 14. Thereby, based on the measurement result of the second vacuum sensor 17 in the state where the vacuum valve 13 is closed, the presence or absence of abnormality such as a decrease in the exhaust capability of the vacuum pump 14 or a vacuum leak in the exhaust piping system 12 is determined. It can be reliably detected with a simple configuration.

  The detection of the presence / absence of such an abnormality can be performed without requiring the apparatus to be stopped while the processing chamber 3a is not being evacuated during the operation of the apparatus, such as during the substrate transfer operation. Therefore, it is possible to improve the operation rate of the apparatus as compared with the prior art in which it is necessary to stop the operation of the apparatus and perform a dedicated test separately. Thereby, the exhaust capability of the vacuum pump and the abnormality of the vacuum piping system for appropriately monitoring the operating state of the apparatus can be easily monitored in an on-line state.

  The plasma processing apparatus of the present invention has an effect that it is possible to easily monitor the exhaust capability of the vacuum pump and the abnormality of the vacuum piping system in order to properly monitor the operating state of the apparatus in an on-line state. It is useful for applications in which surface modification is performed by plasma treatment.

Sectional drawing of the plasma processing apparatus of one embodiment of this invention Flow chart of plasma processing operation in plasma processing apparatus of one embodiment of the present invention Explanatory drawing of operation | movement of the plasma processing apparatus of one embodiment of this invention The graph which shows the time-dependent change of the ultimate vacuum degree in the plasma processing apparatus of one embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 3 Vacuum chamber 3a Processing chamber 5 Electrode main-body part 8 Substrate 11 Substrate conveyance mechanism 12 Exhaust piping system 12a 1st vacuum exhaust piping 12b 2nd vacuum exhaust piping 13 Vacuum valve 14 Vacuum pump 15 1st vacuum sensor (First vacuum measurement unit)
16 Vent valve 17 Second vacuum sensor (second vacuum degree measuring unit)
19 Gas valve 20 Gas supply part 21 High frequency power supply part

Claims (1)

A plasma processing apparatus for performing plasma processing in a reduced-pressure atmosphere on an object to be processed placed in a sealed processing chamber,
A vacuum chamber forming the processing chamber, an electrode portion provided in the vacuum chamber on which the object to be processed is placed, and a vacuum pump connected to the processing chamber via a vacuum exhaust pipe and exhausting the processing chamber A vacuum valve provided in the vacuum exhaust pipe for connecting and disconnecting the processing chamber and the vacuum pump, a gas supply unit for supplying a plasma generating gas into the processing chamber, and a high frequency for applying a high frequency voltage to the electrode unit A power supply unit, a first vacuum measurement unit provided in communication with the processing chamber, and a second vacuum measurement unit provided between the vacuum valve and the vacuum pump in the vacuum exhaust pipe; With
Based on the measurement result of the first vacuum measurement unit, the ultimate vacuum in the processing chamber is measured,
6. A plasma processing apparatus, wherein the presence or absence of abnormality in the vacuum pump and / or the vacuum exhaust pipe is detected based on a measurement result of the second vacuum degree measurement unit in a state where the vacuum valve is closed.

Images