Patent ID: 12217946

DETAILED DESCRIPTION

FIG.1illustrates a configuration example of a substrate treatment apparatus. The substrate treatment apparatus includes a reactor10. The reactor10has a parallel plate structure including, for example, a susceptor10aand an RF plate10b. According to one example, the reactor10includes a gas supply system for providing a gas to a space between the susceptor10aand the RF plate10b. Furthermore, an RF unit10cis provided that applies a high-frequency power to the RF plate10b. According to one example, the RF unit10cincludes an RF generator and a matching box that connects the RF generator with the RF plate10b.

Various types of reactors correspond to the reactor10, which subject a substrate to plasma treatment by applying an electric power to the RF plate. For example, a reactor can apply two different high-frequency powers to the RF plate, or can supply a gas to be used for substrate treatment to a substrate through slits provided in the RF plate.

This reactor10is connected to the PMC14via an analog input unit (AI unit)12that is an Ethernet for Control Automation Technology (Ether CAT) slave. According to one example, the PMC14includes a recipe execution unit14a. The recipe execution unit14aincludes processing circuitry, and the processing circuitry may be dedicated hardware or a CPU (also referred to as Central Processing Unit, central processor, processing unit, arithmetic unit, microprocessor, microcomputer, processor or DSP) that executes a program that is stored in a memory.

FIG.2is a block diagram of the recipe execution unit14ain the case where the processing circuitry is dedicated hardware. The recipe execution unit includes a receiver20a, a processing circuitry20b, and an output device20c. The receiver20areceives analog data that has been measured in the substrate treatment that uses a recipe. The receiver20aacquires, for example, an RF waveform that is a waveform relating to an electric power to be applied to the RF plate10b, from the reactor10through the Ether CAT in real time. The RF waveform is a waveform of, for example, a traveling wave power, reflected wave power, a voltage value to be applied to the RF plate, or a value of an electric current flowing through the RF plate.

The processing circuitry20bcorresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

The respective functions of the recipe execution unit may be realized by the respective processing circuitries, or the respective functions may be collectively realized by the processing circuitry. According to one example, the processing circuitry20bfunctions as a controller that adjusts an electric power to be applied to the RF plate10b, with the use of the RF waveform that has been acquired by the receiver20a.

The output device20cissues a command to the RF unit10c, basically based on the content of the recipe. According to one example, the command includes the RF power, the application time period of the RF power, the cycle of application of the RF power, and the number of times of application of the RF power. Furthermore, when the processing circuitry20bhas adjusted the applied power as described above, the output device20coutputs a command for realizing the adjustment, to the RF unit10c. According to one example, the output device20cissues all instructions relating to RF, to the RF unit10cvia an interface referred to as an ADS board18.

FIG.3is a block diagram illustrating a configuration example of the recipe execution unit14ain the case where the processing circuitry is a CPU. In this case, the above series of processes is controlled by a program. A command to the RF unit10cbased on the recipe and an adjustment of the electric power to be applied to the RF plate10bare automatically performed. When the processing circuitry30bis the CPU as illustrated inFIG.3, each function of the recipe execution unit14ais realized by software, firmware, or a combination of software and firmware. The software or the firmware is described as a program, and is stored in a computer-readable storage medium30c. Information for the above power adjustment is also stored in the storage medium30c. According to one example, the program causes the computer to execute issuing a command to the RF unit10cbased on the recipe, and issuing a command reflecting the above power adjustment to the RF unit10c.

In any of the configurations ofFIGS.2and3, the recipe execution unit14aissues a command for executing a recipe and a command for adjusting the plasma treatment, to the RF unit10c.

InFIG.1, a UPC16is illustrated that is connected to the PMC14. According to one example, the UPC16stores and monitors trend data of analog data created by the PMC14. According to one example, the PMC14functions as an abnormality detection controller. The PMC14can include a calculation unit, a storage unit, an alarm determination unit and a sensor monitoring unit. According to one example, the PMC14issues an alarm when the RF waveform acquired in real time from the reactor10through the Ether CAT exceeds a determined range beforehand. According to one example, UPC16receives alarm signals from the PMC14and displays or records such alarm.

FIG.4is a voltage waveform diagram illustrating an example of adjustment of a voltage to be applied to the RF plate10b. The waveform of the solid line is a target waveform. At the time t1, the RF power starts being applied to the RF plate10b. The PMC14acquires an RF waveform of the electric power applied to the RF plate10b, from the reactor10through the Ether CAT in real time. The voltage waveform that the PMC14has acquired is shown by a broken line. In the target waveform, such a spike occurs that the voltage rises sharply from the time t1to the time t2, and after that, the voltage Vp is maintained. According to one example, the voltage Vp is a sufficient voltage for generating a plasma.

The PMC14acquires the RF waveform in real time, and by using the RF waveform, simultaneously determines whether or not the electric power to be applied to the RF plate10bneeds to be adjusted. In the example ofFIG.4, the PMC14compares the RF waveform from the time t1at which the electric power has started being applied to the RF plate10b, to the first time t2determined beforehand, with a target waveform determined beforehand; and if the value of the RF waveform is smaller than the value of the target waveform, determines that the electric power to be applied to the RF plate needs to be adjusted. In the case ofFIG.4, a voltage in the waveform of the broken line between the time t1and the time t2is insufficient, as compared with that in the target waveform in the same period, and accordingly there is a possibility that the voltage does not reach the voltage Vp required to generate the plasma, and that the plasma is not generated. Then, the PMC14increases the electric power to be applied to the RF plate10bso that the electric power to be applied to the RF plate after the first time t2approaches the target. The amount of increase in the electric power to be applied to the RF plate can be controlled to such a level that the voltage reaches Vp. Thereby, in the example ofFIG.4, after the time t2, the voltage rises as is indicated by the broken line, and reaches the voltage Vp. In addition, it is also illustrated above the waveform that a forward power has been raised at the time t2.

According to another example, the PMC14compares the RF waveform with the target waveform determined beforehand, and if a power value of the RF waveform is greater than the power value of the target waveform, decreases the electric power to be applied to the RF plate so that the electric power to be applied to the RF plate after the first time t2approaches the target.

According to further another example, when a difference between the RF waveform and the target waveform has exceeded a value determined beforehand, the PMC adjusts the electric power to be applied to the RF plate so as to decrease the difference. In this example, it has been determined at the time t2whether or not the electric power needs to be adjusted, but it may be determined based on the data obtained before the time t2whether or not the electric power needs to be adjusted, or may be determined based on the data obtained until after the time t2.

According to one example, the acquisition of the RF waveform and the adjustment of the electric power may be performed each time the electric power is applied to the RF plate in the PEALD process. Then, the substrate treatment apparatus can ensure the generation of the plasma each time the RF power is applied to the RF plate. In addition, the PMC14can acquire the RF waveform with a time resolution shorter than 50 msec.

In this way, by a protocol referred to as the Ether CAT being used for the management of the RF, it becomes possible for the PMC14to monitor the RF waveform in real time and adjust the electric power according to the monitoring result. According to such an example, it becomes possible to construct a monitoring system, due to only the application (module) in the PMC14, specifically, only the recipe execution unit14a. Because of this, the monitoring system can enhance the expandability of a monitoring function, and enables, for example, the power adjustment described above, or the power adjustment that will be described later. According to one example, the PMC14monitors the RF waveform in real time, and determines whether or not an alarm is necessary.

For example, when the RF waveform acquired in real time from the reactor10through the Ether CAT exceeds a range determined beforehand, the PMC14issues the alarm on a real time basis. The UPC16receives the alarm from the PMC14and displays or records such alarm so that user can learn about it on a real time basis.

Furthermore, the PMC14can associate the data of the RF waveform from the beginning to the end of the application of the electric power to the RF plate10bwith the trend data of the UPC.

FIG.5illustrates a state according to another example, in which the electric power to be applied to the RF plate is adjusted. The solid line shows an actually measured voltage waveform. In this adjustment, firstly, a stabilization time is obtained that is a time period between the time of RF-ON (start of application of RF power) and the time when the electric power applied to the RF plate becomes stable. The stabilization time ends at time Ta at which the time period during which the voltage applied to the RF plate is between the upper limit (UL) and the lower limit (LL) exceeds the threshold time. As for the RF waveform, the stabilization time ends when the time period during which the RF waveform transits between the upper threshold and the lower threshold reaches a threshold time determined beforehand.

By the time period being ensured during which a stable voltage is provided, it becomes possible to realize an intended plasma process. Then, the PMC14determines a necessary power application time period that is a time period during which the electric power is to be applied to the RF plate in succeeding times, from the stabilization time. For example, the PMC14can set the sum of the stabilization time and a time period determined beforehand, as the necessary power application time period. Then, the PMC14issues a command to the RF unit10cso as to apply the electric power to the RF plate for the necessary power application time period. This allows the optimum RF application time period to be achieved. The PMC14can view the RF waveform in real time due to the Ether CAT, as described above; and accordingly can sequentially test a plurality of recipes and make the optimum setting. If a system with the PLC logger is used to carry out such processes, the log data is accumulated in the PLC logger, and the PLC logger frequently send the log data to the PMC as the PLC logger is unable to store large data. Further, PMC write the log data, as a log file, to predetermined locations in the UPC. Frequent writing operation made by the PMC imposes a heavy load on the UPC. The log file stored in the UPC can only be checked through the reference of the time stamp.

However, monitoring of the RF waveform in real time by the PMC makes it possible to convert the RF waveform into a form of a graph and adjust setting.

The above substrate treatment apparatus is provided as a PEALD apparatus, for example. The adjustment examples described with reference toFIGS.4and5are by way of example only, and it is also possible to adjust other parameters relating to the RF through real time monitoring of the RF waveform.