Substrate processing apparatus, calibration method

Abstract

To provide a substrate processing apparatus and a calibration method of a light receiving device which are capable of determining a level of the output of the light receiving device.SOLUTION: A substrate processing apparatus is provided with: a chamber containing a stage; light receiving devices to receive light inside the chamber; a shaft; and a rotation arm to rotate with rotation of the shaft. The substrate processing apparatus can supply a plurality of light beams having different amounts of light to at least one of the light receiving devices.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a substrate processing apparatus and a calibration method.

Background Art

[0002] For example, in an ALD process, plasma emission may be detected by a Si photodiode sensor, and the synchronization between the RF-ON instruction output and the plasma emission may be monitored, or the plasma emission intensity may be monitored. However, there is no defense system for diagnosing the state of the photodiode sensor, and there are also individual differences in the output of the photodiode sensor, so level determination cannot be made based on the output value of the photodiode sensor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure has been made to solve the above problems, and an object thereof is to provide a substrate processing apparatus capable of level determination of the output of a light receiving element and a calibration method for the light receiving element.

Means for Solving the Problems

[0005] The substrate processing apparatus according to the present disclosure includes a chamber storing a stage, a light receiving element that receives light inside the chamber, a shaft, and a rotation arm that rotates as the shaft rotates, and provides a plurality of lights having different light amounts to the light receiving element.

[0006] Other features of the present disclosure will be clarified below.

Effects of the Invention

[0007] According to this disclosure, the output of the photodetector can be determined at a level. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of the configuration of a substrate processing apparatus. [Figure 2] This figure shows an example of the characteristics of a light-receiving element. [Figure 3] This is a partial cross-sectional view of a substrate processing device. [Figure 4A] This is a cross-sectional view along line AA in Figure 3. [Figure 4B] This is a cross-sectional view of a shaft in another example. [Figure 5] This is a flowchart showing an example of a calibration method. [Figure 6A] This figure shows an example of the output of a light-receiving element. [Figure 6B] This figure shows an example of the output of a light-receiving element. [Figure 6C] This figure shows an example of the output of a light-receiving element. [Figure 7A] This figure shows the output of multiple photodetectors before calibration. [Figure 7B] This figure shows the output of multiple photodetectors after calibration. [Figure 8] This diagram shows the light from the rotation arm to the photodetector. [Figure 9] This is a diagram showing an luminescent wafer. [Figure 10] This diagram shows a dual-chamber module and an luminescent wafer. [Modes for carrying out the invention]

[0009] The substrate processing apparatus and calibration method will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repetition of descriptions may be omitted.

[0010] Embodiment. FIG. 1 is a diagram showing a configuration example of a substrate processing apparatus. This substrate processing apparatus constitutes a Quad Chamber Module (QCM) having four chamber modules in chamber 10. The number of chamber modules is not particularly limited. According to one example, four chambers 12, 14, 16, and 18 are provided in chamber 10. Chambers 12, 14, 16, and 18 can be provided as, for example, reactor chambers. According to one example, each chamber is a plasma processing apparatus.

[0011] In chambers 12, 14, 16, and 18, there are stages 12a, 14a, 16a, and 18a, respectively. These stages are, for example, susceptors. Outside chambers 12, 14, 16, and 18, light receiving elements 12b, 14b, 16b, and 18b are provided, respectively. According to one example, a plurality of light receiving elements are provided in a one-to-one correspondence with a plurality of chambers. For example, through the viewports of the chambers, the light receiving elements 12b, 14b, 16b, and 18b can receive the light inside chambers 12, 14, 16, and 18, respectively. According to one example, the light receiving elements 12b, 14b, 16b, and 18b are silicon photodiode sensors.

[0012] In chamber 10, a substrate transfer device 20 is provided. According to one example, the substrate transfer device 20 has a shaft 20a and a rotation arm 20b that rotates as the shaft 20a rotates. In the example of FIG. 1, as the shaft 20a extending in the direction perpendicular to the plane of the paper rotates, four rotation arms 20b fixed to the shaft 20a rotate. With this substrate transfer device 20, it becomes possible to move the substrate between the stages.

[0013] A wafer handling chamber (WHC) 30 is connected to chamber 10. The wafer transfer arm in the WHC 30 provides a substrate onto stages 12a and 14a or removes a substrate from stages 12a and 14a.

[0014] According to one example, the process module controller (PMC) 40 receives the outputs of the light-receiving elements 12b, 14b, 16b, 18b, controls the light-receiving elements 12b, 14b, 16b, 18b, and controls the substrate transfer device 20. In this example, the unique platform controller (UPC) 42 instructs the PMC 40 regarding the operation of each module, etc., and the PMC 40 controls each module based on that instruction. According to another example, the control entity for each module can be a controller separate from the UPC 42 and the PMC 40.

[0015] FIG. 2 is a diagram showing an example of the relationship between the amount of incident light on the light-receiving element and the output voltage. According to this example, when the amount of incident light is 160 nW, the output of the light-receiving element varies by about 20% due to individual differences. Also, a linearity error of about 5% occurs in one light-receiving element. Therefore, if the light-receiving elements 12b, 14b, 16b, 18b are used as they are, their outputs cannot be used for level determination or for grasping the difference between chambers.

[0016] FIG. 3 is a partial cross-sectional view of the substrate processing apparatus of FIG. 1. The shaft 20a is a rotating shaft that extends long in the z direction. The substrate transfer device 20 can be moved in the +z direction and the -z direction by a drive mechanism provided inside or outside the chamber 10. For example, holes 20c and 20d are formed in the shaft 20a. The hole 20c is a hole that extends substantially parallel to the z-axis inside the shaft 20a. The hole 20d is a hole that extends substantially perpendicular to the z-axis inside the shaft 20a and connects to the hole 20c. According to one example, a plurality of holes 20d can be provided on the side surface of the shaft 20a.

[0017] In this example, the light source 50 is located outside the chamber 12. The light source 50 may also be located inside the chamber 10, but locating it outside the chamber 12 facilitates maintenance of the light source 50. The light source 50 is turned on and off under the control of, for example, the PMC 40. The light source 50 provides light to the holes 20c and 20d. In one example, the light source 50 and the shaft 20a can be connected by an optical fiber to enable the provision of light to the holes 20c and 20d. In another example, a cavity can be provided in a part of the shaft through which the light source can be inserted and removed, and the light source can be placed in that cavity to enable the provision of light to the holes 20c and 20d. In yet another example, the light source can be located at any position.

[0018] When the light source 50 is turned on, the light passes through holes 20c and 20d and enters the light-receiving elements. By rotating the shaft 20a while emitting light from the light source 50, or by repeatedly rotating the shaft 20a and emitting light from the light source 50, light can be incident on the light-receiving elements 12b, 14b, 16b, and 18b.

[0019] Figure 4A is a cross-sectional view along line AA in Figure 3. Multiple holes 20d are provided on the side of the shaft 20a to allow light from the light source to pass through. In this example, multiple holes 20d with different cross-sectional areas are provided. Light with high light intensity is emitted from the holes with large cross-sectional areas, and light with low light intensity is emitted from the holes with small cross-sectional areas. In Figure 4A, the light La, Lb, Lc, and Ld emitted from the four holes 20d are indicated by arrows. The thickness of the arrows represents the magnitude of the light intensity. The cross-sectional areas of the optical paths of light La, light Lb, light Lc, and light Ld increase in that order, so the light intensity is light La < light Lb < light Lc < light Ld.

[0020] Figure 4B is a cross-sectional view of a shaft according to another example. In this example, the cross-sectional areas of the four holes 20d are substantially the same. The four holes 20d are filled with light-transmitting materials 20e, 20f, 20g, and 20h, which have different light transmittances. The light-transmitting materials 20e, 20f, 20g, and 20h are, for example, ceramics. The light transmittances of the light-transmitting materials 20e, 20f, 20g, and 20h are in this order from least to most abundant. As a result, the light intensity is light La < light Lb < light Lc < light Ld.

[0021] In the examples shown in Figures 4A and 4B, light emitted from a single light source passes through the shaft 20a, is split into multiple beams of light with different intensities, and is provided to the photodetector. By adjusting the shape or material of the shaft in a manner different from that shown in Figures 4A and 4B, it is possible to provide multiple beams of light with different intensities.

[0022] One example of a calibration method for multiple photodetectors involves, in this order, irradiating multiple photodetectors with light from a single light source, and then performing system calibration so that the outputs of the multiple photodetectors become identical when they receive the same amount of light from a single light source. System calibration can also be called scaling.

[0023] Figure 5 is a flowchart showing an example of a calibration method for photodetectors. First, in step S1, multiple lights with different amounts or intensities are incident on the photodetectors 12b, 14b, 16b, and 18b from the side of the shaft 20a in the manner described above. In one example, by providing light while continuously or intermittently rotating the shaft 20a, multiple lights with different intensities are sequentially incident on all photodetectors. For example, light La, Lb, Lc, and Ld are sequentially incident on photodetector 12b, light La, Lb, Lc, and Ld are sequentially incident on photodetector 14b, light La, Lb, Lc, and Ld are sequentially incident on photodetector 16b, and light La, Lb, Lc, and Ld are sequentially incident on photodetector 18b.

[0024] Consequently, as mentioned above, due to errors in the photodetectors, the output of each photodetector varies even though the same intensity of light (La, Lb, Lc, Ld) is incident on all of them. Figure 6A shows examples of the outputs of photodetectors 12b, 14b, 16b, and 18b obtained in step S1. As is clear from this figure, the output for the same light input varies due to variations in the characteristics of the photodetectors.

[0025] If such output variations are found in step S1, the process proceeds to step S2. In step S2, the controllers exemplified by PMC40 and UPC42 are calibrated so that the outputs of multiple photodetectors receiving light of the same intensity from a single light source become identical. Figure 6B shows the result of making the outputs of multiple photodetectors identical through system calibration. The calibration in step S2 makes it possible to make the outputs of multiple photodetectors receiving light of the same intensity identical.

[0026] On the other hand, if, for example, the relationship shown in Figure 6B is obtained in step S1, then such system calibration is naturally unnecessary.

[0027] Next, the relationship between the optical input and the output of the photodetector, obtained with or without calibration, is stored as an initial log in step S3, for example, in a controller or an external storage device.

[0028] Subsequently, after a certain amount of time has elapsed due to processes such as substrate processing using a substrate processing device or substrate transport, the process proceeds to step S4. In step S4, light of the same intensity as during system calibration is incident on multiple photodetectors from a single light source. For example, light La, Lb, Lc, and Ld are sequentially received by all photodetectors. Then, it is confirmed that the outputs of the multiple photodetectors are maintained at the same level. This confirmation can be done by comparing the obtained outputs of the photodetectors with the initial log saved in step S3.

[0029] If at least one of the outputs of the photodetectors obtained in step S4 does not match the initial log, the process proceeds to step S5. Figure 6C shows an example of such a mismatch. In this example, when light of the same intensity as during system calibration is received, the outputs of photodetectors 12b, 14b, and 16b match the initial log, but the output of photodetector 18b does not. A photodetector whose output is not maintained to match the initial log is called an output-variable element. If there is an output-variable element, it is determined whether the difference between the output of the output-variable element and the initial log exceeds a threshold. In other words, it is determined whether the amount of output change of the output-variable element exceeds a threshold. For example, in the example in Figure 6C, it is determined whether the output of the output-variable element is between the upper limit UL and the lower limit LL. If the output of the output-variable element is between the upper limit UL and the lower limit LL, the process proceeds to step S6, and the system is recalibrated so that the outputs of multiple photodetectors become identical. For example, the system is calibrated so that the output of the output-variable element matches the initial log.

[0030] On the other hand, if the output change amount of the output-variable element exceeds the threshold, an alarm is triggered in step S7. In the example in Figure 6C, the output of the photodetector 18b, which is an output-variable element, is lower than the lower limit value LL, so an alarm is triggered.

[0031] In step S4, if the latest output values ​​of multiple photodetectors match the initial log, the process is terminated without recalibration. Steps S4-S7 can be performed periodically or after the completion of specific processes. Periodically checking for the need for recalibration or alarms prevents changes in the output of photodetectors for a given input over time. The calibration and recalibration processes can be performed automatically by the controller.

[0032] Calibrating the outputs of multiple photodetectors in this way enables the determination of the output levels of the photodetectors, for example, in substrate processing involving plasma emission. For instance, it becomes possible to investigate whether substantially equivalent plasma is being generated in multiple chambers, or whether plasma with a predetermined emission intensity is being generated in multiple chambers. If plasma with the desired emission intensity is not being generated in a particular chamber, the processing conditions of that chamber can be changed to achieve the desired emission intensity. One example of this is adjusting the high-frequency power or adjusting the gas supplied to the chamber. In another example, the output of the photodetectors can be fed back into the substrate process conditions.

[0033] Figures 7A and 7B simply illustrate how the outputs of multiple photodetectors are unified through calibration or recalibration. RC# refers to the reactor chamber number.

[0034] In the example shown in Figure 3, the light from the light source 50 is split into multiple beams of light by the shaft 20a. However, according to another example, the light from the light source can be split at any part of the substrate transport device to provide multiple beams of light with different intensities to the photodetector. For example, the light from the light source may be provided to the photodetector from a rotation arm.

[0035] Figure 8 shows how light is supplied from the rotation arms to the photodetector. The multiple rotation arms 20b are formed of a light-transmitting material. Quartz or translucent ceramic can be used as the light-transmitting material.

[0036] The shaft 20a is provided with a hole 20c extending substantially parallel to the z-axis, and a plurality of holes 20d extending from the side surface of the shaft 20a to the hole 20c. The plurality of holes 20d provided on the side surface of the shaft 20a can be holes with different cross-sectional areas, as illustrated in Figure 4A. In another example, as illustrated in Figure 4B, the plurality of holes 20d can be provided with light-transmitting materials with different light transmittances.

[0037] Multiple rotation arms 20b can be provided in a one-to-one correspondence with multiple holes 20d. For example, one rotation arm can be provided adjacent to the exit of one hole 20d. Light from a light source passes through hole 20c and multiple holes 20d, causing the multiple rotation arms to emit light, and light is supplied to multiple photodetectors.

[0038] In another example, light for calibration or recalibration can be supplied from the light-emitting wafer to the photodetector. Figure 9 is a cross-sectional view of the light-emitting wafer 60, etc. In one example, the light-emitting wafer 60 emits light by being equipped with a fluorescent material, a battery and a light-emitting device, or an LED. In another example, an LED-equipped teaching wafer used in the Auto teaching system provided by Cyber ​​Optics can be used as the light-emitting wafer 60. In one example, the light-emitting wafer 60 supplies multiple lights of different light intensities to multiple photodetectors. The light-emitting wafer 60 can be supplied to and removed from the chamber using the same transport system as the product wafer.

[0039] The light-emitting wafer 60 is placed on a stage in one chamber, and light is supplied to a photodetector that monitors the inside of that chamber. Then, the light-emitting wafer 60 is placed on a stage in another chamber, and light is supplied to the photodetector that monitors the inside of that chamber. In this way, by repeatedly moving the light-emitting wafer and supplying reference light to the photodetectors, reference light is supplied from one light-emitting wafer 60 to all the photodetectors.

[0040] In another example, a light-emitting wafer 60 is placed on a rotation arm, and the rotation of the rotation arm is used to cause light to be incident from the light-emitting wafer onto multiple photodetectors.

[0041] Figure 10 shows a Dual Chamber Module (DCM) 51 and a light-emitting wafer 60. In the case of the DCM 51, the light-emitting wafer 60 is placed on a stage 52a in the chamber 52, and reference light is provided from the light-emitting wafer 60 to the photodetector 52b. Furthermore, the light-emitting wafer 60 is placed on a stage 54a in the chamber 54, and reference light is provided from the light-emitting wafer 60 to the photodetector 54b.

[0042] For example, the calibration or recalibration process for the photodetector shown in Figure 5 is the same whether the reference light is supplied to the photodetector from the substrate transport device or from the light-emitting wafer. [Explanation of Symbols]

[0043] 20. Substrate transport device 20a shaft 20b Rotation Arm 12b, 14b, 16b, 18b photodetectors

Claims

1. The process involves directing light from a single light source to multiple photodetectors arranged in a one-to-one correspondence within multiple chambers, A calibration method comprising, in this order, calibrating the system so that the outputs of the multiple photodetectors become the same when the multiple photodetectors receive light of the same intensity from the single light source.

2. The calibration method according to claim 1, characterized in that the system calibration is performed by sequentially irradiating the plurality of light receiving elements with a plurality of light sources of different intensity.

3. The aforementioned multiple chambers constitute the QCM, The calibration method according to claim 1, wherein the light incidence is performed by providing light from a substrate transport device having a shaft and a rotation arm while continuously or intermittently rotating the substrate transport device.

4. The aforementioned multiple chambers constitute the QCM, The calibration method according to claim 1, wherein the light incidence is performed by providing a light-emitting wafer on the stage of the QCM.

5. The aforementioned multiple chambers constitute a DCM, The calibration method according to claim 1, wherein the light incidence is performed by providing a light-emitting wafer on the stage of the DCM.

6. The calibration method according to claim 1, wherein the plurality of chambers are plasma processing devices.

7. The calibration method according to claim 1, further comprising, after the system calibration, inducing light of the same intensity as during the system calibration into the plurality of photodetectors, and confirming whether the output of the plurality of photodetectors is maintained at the same level.

8. The calibration method according to claim 7, further comprising: if, in the verification described above, there is an output-fluctuation element which is a photodetector whose output is not maintained at the same level, the system is recalibrated so that the outputs of the multiple photodetectors become the same level if the amount of change in the output of the output-fluctuation element does not exceed a threshold; and an alarm is issued if the amount of change in the output of the output-fluctuation element exceeds the threshold.

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