JP4936334B2 - Method and system for detecting occurrence of substrate sticking - Google Patents

Description

  The present invention generally relates to a method for detecting occurrence of sticking of a substrate to a supporting surface such as a susceptor surface in a semiconductor manufacturing process.

  During film formation on the substrate, the substrate may be charged and stuck to the electrode. When the substrate is stuck, the lift pin that lifts the substrate for transport is activated, and the stuck substrate may be bounced, causing the substrate to be displaced or cracked.

  If the substrate is transported in this state, the substrate may not be transported to the correct position, and various problems may occur such as dropping during transport or contact with the robot end effector causing damage to the end effector. .

  In one embodiment of the present invention, the sticking of the substrate is detected based on sound and vibration around the chamber. In the case of detecting the sticking of the substrate based on the sound around the chamber, the sticking sound generated in the chamber is erased due to the sound of the apparatus or the surrounding environmental noise, so this sticking sound is detected. It is difficult. However, the sticking sound is generated as a result of contact between the lift pin and the substrate, for example, and this means that the sound can be regarded as vibration. In other words, for example, when the attached substrate is lifted by the lift pins, the substrate jumps, and the sound on the back side of the substrate in contact with the lift pins is transmitted as vibration through the apparatus. By installing a sensor that reduces the influence of environmental noise in a chamber or the like, the sticking sound can be captured as vibration.

  In one embodiment of the present invention, sound, vibration, and other phenomena that occur during substrate transport are monitored by attaching a sensor for detecting sound, vibration, etc. to the processing apparatus. In this way, the sticking sound and vibration can be detected together with the sound and vibration that are not normally generated during the conveyance of the substrate.

  In one embodiment, associated with the substrate by applying a filter that generally or primarily passes sound and vibration associated with the substrate and blocks noise in the environment in which the device is installed, or noise caused by operation of the device. Only sound and vibration with noise can be detected.

  In another embodiment, a timing signal is output from the apparatus when the substrate is lifted to prevent malfunction, and in this case, specifically, only when this signal is output, Sound and vibration are monitored to detect sticking or abnormalities.

  In another embodiment, it is possible to provide a function of stopping the substrate transport process by sending a signal to the processing apparatus when the sticking or abnormality of the substrate is detected.

  In one embodiment, the terms “sound” and “vibration” are used interchangeably.

  In one embodiment of the present invention, a sensor for picking up sound or vibration is provided on the processing apparatus in order to detect substrate sticking or abnormality during substrate transportation, and sticking or abnormality is detected. The transport process is stopped, thereby preventing contact between the substrate and the end effector and avoiding a reduction in the operating rate of the apparatus. When a substrate cracks or comes into contact with an end effector in a processing unit, subsequent device repairs include multiple tasks including internal cleaning, transfer robot teaching, evacuation, and leak checking It takes time to have to carry out. In one embodiment, at least one of the problems described above can be eliminated.

  For purposes of summarizing and describing the present invention and advantages not found in the prior art, certain objects and advantages of the present invention will be described. Of course, it will be appreciated that not all of these objectives or advantages may be realized in accordance with certain embodiments of the invention. Thus, for example, the present invention can be implemented or implemented to achieve or optimize one or a group of advantages taught herein, and not necessarily for other purposes taught or suggested herein. Or it need not achieve an advantage.

  Further aspects, features and advantages of the present invention will become apparent from the detailed description of the following examples.

  These and other features of the present invention are described below with reference to the accompanying drawings depicting preferred embodiments, which are intended to illustrate but not limit the invention. It is drawn. The figures are simplified for convenience of explanation, and the scale is not accurate.

  Details of the present invention will be described below with reference to examples. However, these examples are not intended to limit the invention.

  In one embodiment that can achieve at least one of the objects described above, the present invention provides a processing support comprising a lift pin for raising and lowering a substrate from the surface of the processing support. The present invention provides a method for detecting the occurrence of sticking of a substrate in a reaction chamber for processing a substrate placed on the surface of a body. The method includes (i) a reaction by a sensor installed outside the reaction chamber. Monitoring vibrations propagated in or through the chamber, and (ii) performing a predetermined sequence if this vibration is detected during substrate processing in the reaction chamber. Here, this vibration suggests or identifies the sticking of the substrate to the processing support surface when the substrate is lifted from the processing support surface by the lift pins. And characterized in that.

  The above embodiments include, but are not limited to, the following embodiments that can achieve one or more of the above-mentioned objects.

In one embodiment, vibrations that suggest or identify substrate sticking can be detected when the vibrations have an intensity that exceeds a predetermined threshold. Vibrations that suggest or identify the sticking of the substrate can only be detected when the substrate is moved upward by the lift pins. The step of monitoring vibration includes monitoring acceleration (m / s ² ) of vibration including vibration that suggests or identifies sticking of the substrate. The vibration that suggests or identifies the sticking of the substrate can have a frequency greater than 4 kHz and less than 8 kHz.

  In one embodiment, the step of monitoring vibration comprises: (a) detecting vibrations transmitted in or through the reaction chamber with a sensor; and (b) suggesting sticking of the substrate based on the frequency of the vibration. Filtering the signal output from the sensor to detect vibrations that occur. In the case of the example described above, the signal filtering step includes (b1) filtering and excluding a signal portion having a frequency of 4 kHz or less, and (b2) filtering and excluding a signal portion having a frequency of 8 kHz or more. Process.

  In one embodiment, the step of performing the predetermined sequence may include issuing a warning signal and stopping the conveyance of the substrate.

  In one embodiment, the sensor may be a piezoelectric element that outputs electrons.

  In one embodiment, the sensor can be placed on the outer surface of a portion of the reaction chamber, which conveys vibration due to shock that occurs when the backside of the substrate strikes the tip of the lift pin. Is a possible part. The sensor can be placed on the outer metal surface at the bottom of the reaction chamber. The processing support can be a susceptor and the reaction chamber can be a semiconductor process reactor. The lift pin may be inserted into a through hole formed in the axial direction through the surface of the support pin. The vibration that suggests or specifies the sticking of the substrate may be detected only when the film is formed on the substrate and the substrate is moved by the lift pins after the susceptor is lowered to the substrate transfer arrangement.

  The present invention can be applied to the system as well. In one embodiment, the present invention processes a substrate placed on the surface of a processing support including lift pins for raising and lowering the substrate from the surface of the processing support. A system for detecting occurrence of substrate sticking in a reaction chamber is provided, the system being installed outside the reaction chamber to monitor vibrations propagated in or through the reaction chamber (i) And (ii) a controller for performing a predetermined sequence if this vibration is detected while processing the substrate in the reaction chamber, wherein the vibration Is characterized by suggesting or specifying the sticking of the substrate to the processing support surface when the substrate is lifted from the processing support surface by the lift pins. That.

  The above embodiments include, but are not limited to, the following embodiments that can achieve one or more of the above-mentioned objects.

The controller can detect vibrations that suggest or identify substrate sticking when the vibrations have an intensity that exceeds a predetermined threshold. The controller may detect a vibration that suggests or identifies the sticking of the substrate only when the substrate is lifted by the lift pins. The sensor can monitor acceleration (m / s ² ) of vibrations including vibrations that suggest or identify substrate sticking.

  The sensor may be adapted to monitor vibrations having a frequency above 4 kHz and below 8 kHz. The system may further comprise a band pass filter that filters signal portions having a frequency of 4 kHz or less and signal portions having a frequency of 8 kHz or more. When the controller detects vibration, it can issue a warning signal and stop the substrate transfer process.

  In the above description, these method embodiments and system embodiments may be used singly or in any combination, and may alternatively be utilized.

  As described above, when the film is formed on the support for film formation processing in the processing apparatus and is attached to the support by charging, this sticking causes the post-treatment. When the substrate is lifted by lift pins, the substrate may jump, or some abnormality may occur and the substrate may be displaced or cracked. If the transfer process is performed in this state, the substrate will not be picked up from the correct position and will fall during transfer, cracks will occur, or the end effector of the transfer robot will be touched and eventually damaged. There is a possibility of giving. If the substrate cracks or the end effector is damaged, the processing equipment line must be opened to the atmosphere. The restoration of the apparatus takes time, and the utilization rate of the processing apparatus decreases. In one embodiment of the present invention, substrate bounce or anomaly during transfer due to sticking is captured as a sound, i.e. vibration, suggesting contact between the substrate and lift pins, or the substrate and support, such as An abnormality of the substrate is detected. An embodiment of the present invention will be described below with reference to the drawings. However, it goes without saying that the present invention is not limited to these figures or examples.

The processing apparatus shown in FIG. 1 is a plasma CVD film forming apparatus 1. The application of the present invention is not limited to a plasma CVD film forming apparatus, but is used for a thermal CVD film forming apparatus, a plasma or thermal ALD film forming apparatus, an etching apparatus, an annealing apparatus, a UV irradiation apparatus, and a substrate processing. It can be applied to other devices. The apparatus shown in FIG. 1 usually has a plurality of lift pins 3 (generally three, though there are four or more) that pass through a processing support (susceptor) 2 on which a substrate 4 is arranged. The substrate 4 on the support is lifted or lowered from the surface of the support in conjunction with the vertical movement of the processing support 2.

  In the present embodiment, a sensor 5 for capturing sound and vibration is provided on the apparatus. The sensor 5 can detect contact sound and vibration by picking up a frequency of several Hz to about 20 kHz, but is suitable for detecting contact sound and vibration that suggests sticking of the substrate. Any other sensor may be used as long as it is a simple one. The sensor 5 used in the present embodiment is a charge output type contact acceleration pickup using a piezoelectric element, but a sensor using a built-in preamplifier can also be used to output a voltage. As long as the sensor is suitable for detecting the sticking sound and vibration of the substrate, any model or type of sensor can be selected without restriction. However, when the chamber is exposed to a high temperature, it is desirable to use a charge output type sensor that does not use a built-in amplifier so as to withstand the high temperature. As an example of an actual sensor element, a charge output type sensor (Ono Sokki: NP2130) connected to a determination device via a charge converter (Ono Sokki: 6130) that converts a charge into a voltage can be cited. However, the sensor element is not limited to this configuration.

  In this example, the signal from the sensor 5 is converted or amplified by a charge converter or amplifier 11 to provide a band pass filter that extracts the frequency of sound and vibrations suggesting contact between the substrate and lift pins or between the substrate and support. The filtered and then filtered signal is sent to a filter / determination circuit 12 that determines anomalies against the vibration acceleration threshold. A general control motor or the like generates vibrations of 4 kHz or less, and in addition, by considering an evaluation result obtained from an actual apparatus, in one embodiment, frequencies of 4 kHz or less and 8 kHz or more are filtered.

  Whether or not to apply the filter, which frequency is filtered out, and which frequency is detected may be selected based on the sticking sound and vibration to be detected. The generation of sticking sound and vibration is accompanied by the propagation characteristics of vibration, the material and shape of the lift pins, the material and shape of the sticking surface of the substrate, the material and shape of the support surface, the material and shape of the inner wall of the device, It may vary depending on the structure, driving components, the structure of the components constituting the driving mechanism and other devices, peripheral devices used around the device, etc., and further depending on the degree of sticking of the substrate and the type of processing applied . Therefore, in one embodiment, it is desirable that the effective frequency for detecting sticking sound and vibration, the frequency to be filtered, the detection threshold, and other matters can be set in advance for each target in consideration of the characteristics of the sensor and the like. . As a result, in one embodiment, sticking can be effectively detected in the 4 to 8 kHz range, while the lower limit is 0.5, 1, 2, 3, 4, 5, 6 or 7 kHz, and the upper limit is A desired detection range that seems to be appropriate in a range of 5, 6, 7, 8, 9, 10, 15 or 20 kHz may be set in combination. In other embodiments, frequency ranges other than those described above may be used for detection. The measurement frequency range described above need only be effective for detecting vibration in the application range, and as long as it is possible, it is not necessary to use a filter, or the level of the filter can be adjusted appropriately. is there. The threshold can be set so that detection is possible. For example, in a noisy environment, the setting allows detection of intensity 1.3 times or more (for example, 1.5 times or 2 times) of the measured value. In an environment where the noise is small, it is possible to set to allow detection of an intensity of 1.1 times or more (for example, 1.2 times) of the measured value. A vibration waveform in the measurement frequency range may be used instead of the threshold corresponding to the predetermined frequency range.

  Examples of filters include hardware circuit filters (LC circuits) and digital (software) filters. In one embodiment, a digital filter can be applied as implementing the decision device. Specifically, the vibration is converted into a voltage change (frequency) and then digitized and sent to software that cuts off a predetermined frequency.

  Next, when the determination circuit determines that sticking has been detected, an appropriate determination signal is sent to the apparatus controller 13, the substrate transfer process is stopped, and a warning is transmitted. As a result, control for stopping the operations of the transfer robot 21 and the end effector 22 is executed.

  In order to prevent malfunction due to normal determination processing, when a substrate lift-up timing signal is output from another device controller (not shown) to the determination circuit, this signal is output to the determination circuit. It is possible to start or stop the determination process.

Specific physical quantities for detecting the occurrence of sticking include sound pressure, displacement, acceleration, or other quantities that indicate vibration. In the following example, acceleration (m / s ² ) of these is used. Vibration can also be expressed in dB which is a dimensionless unit.

  The position of the sensor 5 is not particularly limited. In FIG. 1, the lift pin 3 is in contact with the bottom of the reaction chamber 1, but vibration can be sufficiently detected in the apparatus even when the lift pin is not in contact with the reaction chamber. The lift pins are installed in the bottom part of the reaction chamber in FIG. 1, but the pins can also be installed on the side or top surface. However, the upper surface of the apparatus of FIG. 1 has another structure (shower head structure), and the side surface is covered with a heat insulating material cover. The lift pins cannot be directly contacted with the reaction chamber to which sound (vibration) is transmitted due to these factors. Therefore, the lift pins are provided on the bottom surface which is the only exposed surface. The sensor is generally installed on the exterior of the apparatus. Since the reaction chamber is filled with active gas, it is difficult to install vibration sensors and signal cables inside the reaction chamber. However, if these are protected with a material resistant to active gas, It is possible to install.

FIG. 2 is an example of a flowchart showing how sticking is actually detected. First, a processing apparatus is started and a substrate placed on a susceptor is processed (step 1). Next, the sticking vibration transmitted through the processing device using a sensor is monitored (step 2). After the film is formed, the susceptor is pulled down and the substrate is lifted from the susceptor by lift pins. When the filter was not applied, the vibration acceleration in the measurement frequency range (several Hz to about 20 kHz) when sticking (abnormal sound) did not occur was 8.32 m / s ² . When sticking (abnormal sound) occurred, the vibration acceleration in the measurement frequency range was 9.88 m / s ² . Even if sticking occurs in this state, the acceleration may not be clearly different depending on the sticking state or other noise states. When applying a filter (cutting 4 kHz or less and 8 kHz or more) (step 3), when the sticking does not occur, the vibration acceleration is 2.2 m / s ² , but when sticking occurs Since the vibration acceleration of was 3.76 m / s ² , the determination was easy (step 4). In other words, in the above example where the filter was not applied, the acceleration when sticking occurred increased only 1.2 times that when sticking did not occur, and the filter was applied The acceleration increased 1.7 times. The filter cuts the sound and vibration acceleration that are not related to sticking, and if not filtered, enables identification of the vibration acceleration indicating sticking that has been erased by other sounds and vibrations. .

  The substrate can be made of silicon, quartz, gallium arsenide, etc., and the lift pins can be made of aluminum or ceramic, depending on the device. These material differences can affect the sticking vibration. In addition, since vibrations in the production line and adjacent devices may adversely affect detection, it is desirable to always check the noise frequency and set the threshold value at the start of work. In one embodiment, the cutoff frequency can be changed by the determination device, and the filter frequency is also variable.

  In order to avoid malfunctions caused by the determination process during normal operation, a substrate lift-up timing signal is output from the apparatus controller to the determination circuit (step 5), and this signal is used when this signal is output to the determination circuit. The determination process can be started or stopped. As a result, when it is determined that sticking occurs in step 4, a command is sent to the processing device controller (step 5), and the conveyance process is stopped by this command and a warning is transmitted (step 6).

  In the present disclosure, for those portions in which conditions and / or structures are not specified, those skilled in the art can easily obtain such conditions and / or structures by routine experimentation in light of the present disclosure. .

  It will be apparent to those skilled in the art that many different modifications can be made without departing from the spirit of the invention. Thus, it should be apparent that the embodiments of the present invention are intended for illustrative purposes only and are not intended to limit the scope of the present invention.

It is the schematic of the sticking detection system for plasma CVD apparatuses based on one Example of this invention. It is a flowchart of the sticking detection method for plasma CVD apparatuses based on one Example of this invention.

Explanation of symbols

1 Processing equipment (reaction chamber)
2 Support for processing (susceptor)
3 Lift pin 4 Substrate 5 Sensor 13 Controller

Claims (23)

In a reaction chamber for processing the substrate placed on the surface of the processing support, the processing support comprising lift pins for raising and lowering the substrate from the surface of the processing support. A method for detecting an occurrence
Monitoring vibrations propagated in or through the reaction chamber with a sensor;
Performing a predetermined sequence if vibrations determined to have occurred while the substrate is being processed while the substrate is being processed in the reaction chamber; and
Including
The vibration determined to have caused the sticking of the substrate is a vibration caused by an impact when the back surface of the substrate jumps at the tip of the lift pin when the substrate is lifted from the front surface of the processing support by the lift pin. When it is determined that the acceleration (m / s ² ) has a strength exceeding a predetermined threshold value, the substrate is suggested or specified to adhere to the surface of the processing support. how to.   The method of claim 1, wherein the vibration indicative of or identifying sticking of the substrate is detected only when the substrate is lifted by the lift pins. The method of claim 1, wherein monitoring the vibration comprises monitoring a vibration acceleration (m / s ² ) including the vibration that suggests or identifies sticking of the substrate.   2. The method of claim 1, wherein the vibration indicating or identifying the sticking of the substrate has a frequency greater than 4 kHz and less than 8 kHz. Monitoring the vibration comprises:
Detecting the vibration propagated in or through the reaction chamber by the sensor, and the sensor to detect the vibration indicative of sticking of the substrate based on the frequency of the vibration And filtering the signal output from the method. Filtering the signal comprises:
6. The method of claim 5 , comprising filtering and removing signal portions having a frequency of 4 kHz or less, and filtering and removing signal portions having a frequency of 8 kHz or more.   The method according to claim 1, wherein the step of performing the predetermined sequence includes transmitting a warning signal and stopping the substrate transfer process.   The method according to claim 1, wherein the sensor uses a piezoelectric element that outputs electrons.   The sensor is provided on an outer surface of a part of the reaction chamber, and the part is a part capable of propagating a vibration caused by an impact generated when the back surface of the substrate jumps at a tip of the lift pin. The method of claim 1, wherein: The method of claim 9 , wherein the sensor is provided on an outer metal surface at the bottom of the reaction chamber.   The method of claim 1, wherein the processing support is a susceptor and the reaction chamber is a semiconductor process reactor. The method of claim 11 , wherein the lift pin is inserted axially through the surface into a through hole formed in the susceptor . After the film is formed on the substrate and the susceptor is lowered to the transporting position of the substrate, the vibration indicating the sticking of the substrate is detected only when the substrate is lifted by the lift pins. 13. The method of claim 12 , wherein: In a reaction chamber for processing the substrate placed on the surface of the processing support, the processing support comprising lift pins for raising and lowering the substrate from the surface of the processing support. A system for detecting occurrences
A sensor for monitoring vibrations propagated in or through the reaction chamber;
A controller that performs a predetermined sequence if vibrations determined to have occurred while the substrate is being processed while the substrate is being processed in the reaction chamber;
Including
The vibration determined to have caused the sticking of the substrate is a vibration caused by an impact when the back surface of the substrate jumps at the tip of the lift pin when the substrate is lifted from the front surface of the processing support by the lift pin. When it is determined by the determination device that the acceleration (m / s ² ) has a strength exceeding a predetermined threshold value, it indicates or specifies that the substrate adheres to the surface of the processing support. A system characterized by 15. The system according to claim 14 , wherein the determination device determines the vibration that suggests or specifies the sticking of the substrate only when the substrate is lifted by the lift pins. The system according to claim 14 , wherein the sensor monitors vibration acceleration (m / s ² ) including the vibration indicating or specifying the sticking of the substrate. 15. The system of claim 14 , wherein the sensor monitors vibrations having a frequency greater than 4 kHz and less than 8 kHz. 15. The system of claim 14 , further comprising a band pass filter that filters out signal portions having a frequency of 4 kHz or less and signal portions having a frequency of 8 kHz or more. The system according to claim 14 , wherein when a vibration that suggests or specifies the sticking of the substrate is detected, the controller issues a warning signal and stops the substrate transfer process. The system according to claim 14 , wherein the sensor is a sensor using a piezoelectric element that outputs electrons. The sensor is provided on an outer surface of a part of the reaction chamber, and the part is a part capable of propagating a vibration caused by an impact generated when the back surface of the substrate jumps at a tip of the lift pin. The system according to claim 14 , wherein: The system of claim 21 , wherein the sensor is provided on an outer metal surface at the bottom of the reaction chamber. 15. The system of claim 14 , wherein the processing support is a susceptor and the reaction chamber is a semiconductor process reactor.

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