Patent ID: 12218269

DETAILED DESCRIPTION

A substrate processing apparatus and a calibration method will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals and description thereof may not be repeated.

FIG.1is a diagram illustrating a configuration example of a substrate processing apparatus. The substrate processing apparatus forms a quad chamber module (QCM) in which four chamber modules are provided in a chamber10. The number of chamber modules is not particularly limited. According to an example, four chambers12,14,16, and18are provided in the chamber10. The chambers12,14,16, and18can be provided as reactor chambers, for example. According to an example, each of the chambers is a plasma processing apparatus.

Stages12a,14a,16a, and18aare provided inside the chambers12,14,16, and18, respectively. These stages are, for example, susceptors. Light receiving devices12b,14b,16b, and18bare provided outside the chamber12,14,16, and18, respectively. According to an example, a plurality of light receiving devices are provided in one-to-one correspondence with a plurality of chambers. For example, the light receiving devices12b,14b,16b, and18bcan receive light inside the chambers12,14,16, and18through viewports of the chambers, respectively. According to an example, the light receiving devices12b,14b,16b, and18bare silicon photodiode sensors.

A substrate transfer apparatus20is provided in the chamber10. According to an example, the substrate transfer apparatus20includes a shaft20aand rotation arms20bthat rotate with the rotation of the shaft20a. In the example ofFIG.1, four rotation arms20bfixed to the shaft20arotate with the rotation of the shaft20aextending in a direction perpendicular to the paper. A substrate can be moved between the stages by the substrate transfer apparatus20.

A wafer handling chamber (WHC)30is connected to the chamber10. A wafer transfer arm present in the WHC30provides the substrate on the stages12aand14aor removes the substrate from the stages12aand14a.

According to an example, a process module controller (PMC)40receives outputs of the light receiving devices12b,14b,16b, and18b, controls the light receiving devices12b,14b,16b, and18b, and controls the substrate transfer apparatus20. In this example, a unique platform controller (UPC)42instructs the PMC40to operate each of the modules, and the PMC40controls each of the modules based on the instruction. According to another example, each of the modules can be controlled by a controller different from the UPC42and the PMC40.

FIG.2is a diagram illustrating an example of a relation between an amount of light incident on the light receiving device and an output voltage. According to this example, when the amount of incident light is 160 nW, the output of the light receiving device varies by about 20% due to individual differences. In addition, a linearity error of one light receiving device also occurs about 5%. Accordingly, when the light receiving devices12b,14b,16b, and18bare used without taking a measure, the outputs thereof can hardly be used for level determination or used for understanding differences between the chambers.

FIG.3is a partial cross-sectional view of the substrate processing apparatus inFIG.1. The shaft20ais a rotating shaft extending long in a z-direction. The substrate transfer apparatus20can be moved in a positive z-direction and a negative z-direction by a driving mechanism provided inside or outside the chamber10. The shaft20ais formed with a hole20cand a hole20d, for example. The hole20cis a hole extending in the shaft20ain substantially parallel with a z-axis. The hole20dis a hole extending in the shaft20aso as to be substantially perpendicular to the z-axis and coupled to the hole20c. According to an example, a plurality of holes20dcan be provided on a side face of the shaft20a.

In this example, a light source50is provided outside the chamber12. The light source50may be provided inside the chamber10. However, when the light source50is provided outside the chamber12, maintenance of the light source50is facilitated. The light source50is turned on and off under the control of the PMC40, for example. The light source50supplies light to the holes20cand20d. According to an example, the light source50is connected to the shaft20aby an optical fiber, and thus the light can be supplied to the holes20cand20d. According to another example, a part of the shaft is provided with a cavity through which the light source can be inserted and removed, the light source is provided in the cavity, and thus the light can also be supplied to the holes20cand20d. According to further another example, the light source can be provided at an arbitrary position.

When the light source50is turned on, the light is incident on the light receiving devices through the holes20cand20d. The light can be incident on the light receiving device12b,14b,16b, and18bby light emission of the light source50with the rotation of the shaft20aor repetition of the rotation of the shaft20aand the light emission of the light source50.

FIG.4Ais a cross-sectional view taken along line A-A inFIG.3. The side face of the shaft20ais provided with a plurality of holes20dthrough which the light of the light source passes. In this example, the plurality of holes20dhaving different cross-sectional areas are provided. Light having a high light intensity is emitted from the hole having a large cross-sectional area, and light having a low light intensity is emitted from the hole having a small cross-sectional area. InFIG.4A, light La, Lb, Lc, and Ld emitted from four holes20dare indicated by arrows. A thickness of the arrow indicates magnitude of the light intensity. Since the cross-sectional area of the light path of the light La, the cross-sectional area of the light path of the light Lb, the cross-sectional area of the light path of the light Lc, and the cross-sectional area of the light path of the light Ld increase in this order, the light intensity satisfies a relation of light La<light Lb<light Lc<light Ld.

FIG.4Bis a cross-sectional view of a shaft according to another example. In this example, four holes20dhave substantially an identical cross-sectional area. The four holes20dare provided with light transmitting materials20e,20f,20g, and20hwhich are different in light transmissivity from each other. The light transmitting materials20e,20f,20g, and20hare, for example, ceramics. The light transmitting material20ehas the lowest light transmissivity, followed in order by light transmitting materials20f,20g, and20h. As a result, the light intensity satisfies a relation of light La<light Lb<light Lc<light Ld.

In the examples ofFIGS.4A and4B, the light emitted from one light source passes through the inside of the shaft20aand is divided into a plurality of light beams which are different in light intensity from each other, and the divided light are supplied to the light receiving devices. By adjustment of the shape or material of the shaft in a different manner from that inFIGS.4A and4B, a plurality of light beams having different light intensities can be supplied.

According to an example, a calibration method of the plurality of light receiving devices includes allowing light to be incident on the plurality of light receiving devices from one light source and subsequently performing a system calibration such that outputs of the plurality of light receiving devices are identical to each other when the plurality of light receiving devices receive light having the identical amount of light from one light source. The system calibration can also be referred to as scaling.

FIG.5is a flowchart illustrating an example of the calibration method of the light receiving devices. First, in step S1, the plurality of light beams, which are different in amount of light or light intensity from each other, are incident on the light receiving devices12b,14b,16b, and18bfrom the side face of the shaft20ain the manner described above. According to an example, light is supplied with the rotation of the shaft20ain a continuous or intermittent way, and thus a plurality of light beams having different light intensities are sequentially incident on all of the light receiving devices. For example, the light La, Lb, Lc, and Ld are sequentially incident on the light receiving device12b, the light La, Lb, Lc, and Ld are sequentially incident on the light receiving device14b, the light La, Lb, Lc, and Ld are sequentially incident on the light receiving device16b, and the light La, Lb, Lc, and Ld are sequentially incident on the light receiving device18b.

Then, as described above, the outputs of the light receiving devices vary due to the error of the light receiving devices even though the light La, Lb, Lc, and Ld having the identical light intensity are incident on all of the light receiving devices.FIG.6Ais a diagram illustrating an example of the outputs of the light receiving device12b,14b,16b, and18bobtained in step S1. As is clear from this drawing, variation occurs in the outputs with respect to the identical light input due to characteristic variations of the light receiving devices.

When such output variation is detected in step S1, the process proceeds to step S2. In step S2, the controllers exemplified by the PMC40and the UPC42perform system calibration such that the outputs of the plurality of light receiving devices receiving the light having the identical amount of light from one light source are identical to each other.FIG.6Bis a diagram illustrating that the outputs of the plurality of light receiving devices are made identical by the system calibration. By the calibration in step S2, the outputs of the plurality of light receiving devices receiving the light with the identical light intensity can be made identical.

On the other hand, when the relation illustrated inFIG.6Bis obtained in step S1, for example, such a system calibration is naturally unnecessary.

Subsequently, a relation between the light inputs and the outputs of the light receiving devices through the calibration or without the calibration is stored as an initial log in, for example, the controller or an external storage device in step S3.

Thereafter, for example, after a certain period of time has elapsed since the processing of the substrate using the substrate processing apparatus or the transfer of the substrate is performed, the process proceeds to step S4. In step S4, the light having the amount of light identical to that at the time of the system calibration is incident on the plurality of light receiving devices from one light source. For example, the light La, Lb, Lc, and Ld are sequentially received by all of the light receiving devices. Then, it is confirmed whether the outputs of the plurality of light receiving devices are maintained to be identical to each other. Such a confirmation can be performed by comparison between the obtained outputs of the light receiving devices and the initial log stored in step S3.

When at least one of the outputs of the light receiving devices obtained in step S4does not match the initial log, the process proceeds to step S5.FIG.6Cis a diagram illustrating an example of such a miss match. In this example, when the light having the amount of light identical to that at the time of the system calibration is received, the outputs of the light receiving devices12b,14b, and16bmatch the initial log, but the output of the light receiving device18bdoes not match the initial log. The light receiving device having the output not match the initial log is referred to as an output variation device. When the output variation device is present, it is determined whether the difference between the output of the output variation device and the initial log exceeds a threshold. In other words, it is determined whether the output change amount of the output variation device exceeds the threshold. For example, it is determined in the example ofFIG.6Cwhether the output of the output variation device is in a range between an upper limit value UL and a lower limit value LL. When the output of the output variation device is in the range between the upper limit value UL and the lower limit value LL, the process proceeds to step S6, and the system is re-calibrated such that the outputs of the plurality of light receiving devices are identical to each other. For example, calibration is performed such that the output of the output variation device matches the initial log.

On the other hand, when the output change amount of the output variation device exceeds the threshold, an alarm is issued in step S7. In the example ofFIG.6C, since the output of the light receiving device18b, which is an output variation device, is lower than the lower limit value LL, an alarm is issued.

When the latest output values of the plurality of light receiving devices match the initial log in step S4, the process ends without re-calibration. Steps S4to S7can be performed periodically or after the end of a specific process. The confirmation of the necessity of periodical re-calibration or the necessity of alarming makes it possible to prevent the outputs of the light receiving devices from changing with respect to the constant input with the lapse of time. The calibration process and the re-calibration process can be performed by automatic processing of the controller.

By the calibration of the outputs of the plurality of light receiving devices in this manner, the output levels of the light receiving devices can be determined, for example, in substrate processing involving plasma emission. For example, it is possible to investigate whether substantially identical plasma is generated in a plurality of chambers, and to investigate whether plasma having an emission intensity in a predetermined range is generated in the plurality of chambers. When plasma having an intended emission intensity is not generated in a specific chamber, processing conditions of the chamber can be changed in order to realize the plasma having the intended emission intensity. As an example, high-frequency power is adjusted or a gas supplied to the chamber can be adjusted. According to another example, the outputs of the light receiving devices can be fed back to the process condition of the substrate.

FIGS.7A and7Bare diagrams simply illustrating that the outputs of the plurality of light receiving devices are unified by calibration or re-calibration. A symbol RC #represents a reactor chamber number.

In the example ofFIG.3, the light of the light source50is divided into a plurality of light beams by the shaft20a. However, according to another example, the light of the light source is divided at an arbitrary portion of the substrate transfer apparatus, and a plurality of light beams having different light intensities can be supplied to the light receiving devices. For example, the light of the light source may be supplied from the rotation arm to the light receiving devices.

FIG.8is a diagram illustrating that light is supplied from a rotation arm to a light receiving device. A plurality of rotation arms20bare formed of a light transmitting material that transmits light. As an example of the light transmitting material, quartz or translucent ceramic may be used.

A shaft20ais provided with holes20cextending in a direction substantially parallel to the z-axis and a plurality of holes20dextending from the side face of the shaft20ato the hole20c. The plurality of holes20dprovided on the side face of the shaft20acan be holes having different cross-sectional areas as illustrated inFIG.4A. According to another example, the plurality of holes20dcan also be provided with light transmitting materials which are different in light transmissivity from each other as illustrated inFIG.4B.

The plurality of rotation arms20bcan be provided in one-to-one correspondence with the plurality of holes20d. For example, one rotation arm is provided adjacent to the outlet of one hole20d. The light from the light source passes through the holes20cand the plurality of holes20d, the plurality of rotation arms emit light, and thus the light is supplied to the plurality of light receiving devices.

According to another example, light for calibration or re-calibration can be supplied from a light emitting wafer to light receiving devices.FIG.9is a cross-sectional view of a light emitting wafer60and other parts. According to an example, the light emitting wafer60includes a fluorescent material, includes a battery and a light emitting device, or includes an LED, thereby emitting light. According to another example, the light emitting wafer60may employ an LED-mounted teaching wafer used in an Auto teaching system presented by cyber optics Corp. According to an example, the light emitting wafer60supplies a plurality of light beams having different amounts of light to the plurality of light receiving devices. The light emitting wafer60can be provided to or taken out of the chamber by a transfer system used for a product wafer.

The light emitting wafer60is placed on a stage in a certain chamber, and supplies light to a light receiving device that monitors the inside of the chamber. Then, the light emitting wafer60is placed on a stage in another chamber, and supplies light to a light receiving device that monitors the inside of the chamber. Thus, the movement of the light emitting wafer and the supply of the reference light to the light receiving devices are repeatedly performed in this manner, the reference light is supplied from one light emitting wafer60to all of the light receiving devices.

According to another example, the light emitting wafer60is placed on the rotation arm, and the light is incident on the plurality of light receiving devices from the light emitting wafer using the rotation of the rotation arm.

FIG.10is a diagram illustrating a dual chamber module (DCM)51and a light emitting wafer60. In a case of the DCM51, the light emitting wafer60is placed on a stage52ain a chamber52, and reference light is supplied from the light emitting wafer60to a light receiving device52b. Further, the light emitting wafer60is placed on a stage54ain a chamber54, and reference light is supplied from the light emitting wafer60to a light receiving device54b.

For example, the processing for calibration or re-calibration of the light receiving devices inFIG.5is identically applied to the case where the reference light is supplied from the substrate transfer apparatus to the light receiving device and the case where the reference light is supplied from the light emitting wafer to the light receiving devices.