JP7389695B2 - Wafer transfer device - Google Patents

Description

The present invention relates to a wafer transfer device.

Patent Document 1 describes that a camera is installed on the outside of a wafer storage container, and the camera is configured to detect or observe the inside of the transport container through an observation window. Furthermore, Patent Document 1 describes that the wafer temperature within the wafer storage container is measured by a temperature sensor.

JP2019-212908A

Wafers to be processed are transported from a cassette (wafer storage container) to a wafer processing unit, which is a host device, by a transport robot. The processed wafer is returned to the cassette by a transfer robot.

By the way, during wafer processing, the cassette may be replaced with another one for some reason. Since each cassette has individual differences in shape and size, there is a risk that the cassette will be misaligned. Furthermore, misalignment may also occur if a worker or robot touches the cassette.

However, since the distance between the wafers in the cassette is very narrow, if a positional shift occurs, the arm of the transfer robot may inadvertently touch the wafers or the cassette, or the wafers may come into contact with each other. Therefore, cracks, scratches, scratches, etc. may occur on the wafer. In this way, there is a wafer transfer risk in the wafer transfer unit.

Therefore, an object of the present invention is to provide a wafer transfer device that reduces the risk of wafer transfer.

A brief overview of typical inventions disclosed in this application is as follows.

A wafer transfer apparatus according to a typical embodiment of the present invention includes a wafer transfer robot that takes out a wafer from a wafer storage container in which a plurality of wafer guides are provided and stores the wafer in the wafer storage container; a mapping sensor that senses the position of the wafer containing the wafer; a camera that is installed at a position facing the wafer container and generates a captured image that includes the wafer container; The computer system includes a computer system that acquires mapping information of a wafer, acquires image wafer information based on a captured image after image processing, and compares the mapping information and the image wafer information.

Among the inventions disclosed in this application, the effects obtained by typical inventions are briefly explained below.

That is, according to the representative embodiment of the present invention, it is possible to reduce the risk of wafer transportation.

1 is a perspective view showing an example of a semiconductor manufacturing apparatus including a wafer transport device according to Embodiment 1 of the present invention. 1 is a top view showing an example of the configuration of a wafer transfer device according to Embodiment 1 of the present invention. 1 is a side view showing an example of the configuration of a wafer transport unit according to Embodiment 1 of the present invention. 1 is a side view showing an example of the configuration of a wafer transport unit according to Embodiment 1 of the present invention. FIG. 2 is a front view showing an example of the configuration of a cassette. FIG. 2 is a flow diagram showing an example of a position detection method according to Embodiment 1 of the present invention. FIG. 3 is a diagram illustrating an outline of a mapping operation and an example of a wafer position detection result. FIG. 3 is a diagram illustrating the arrangement of wafers including a case where an abnormality in the thickness of the wafer is detected. It is a figure which shows an example of the captured image used for the dimension measurement process of a cassette. 10 is a diagram showing an enlarged image of FIG. 9. FIG. FIG. 3 is a diagram illustrating a captured image. FIG. 2 is a diagram illustrating a GUI. 13 is a diagram showing a GUI that is an enlarged display of FIG. 12. FIG. FIG. 3 is a diagram illustrating a GUI on which a thermography image is displayed. FIG. 3 is a diagram illustrating a GUI that displays a warning. This is a GUI showing a state in which a wafer can be accommodated in the first slot from the bottom after the cassette measurement process shown in FIG. 6. 13 is a diagram illustrating an example in which the number of slot stages of the cassette displayed in the wafer check box in FIG. 12 is calculated by image processing. FIG. FIG. 7 is a flow diagram showing an example of a position detection method according to Embodiment 2 of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. Each embodiment described below is an example for realizing the present invention, and does not limit the technical scope of the present invention. In the embodiments, members having the same functions are denoted by the same reference numerals, and repeated explanations thereof will be omitted unless particularly necessary.

(Embodiment 1)
<Overview of semiconductor manufacturing equipment including wafer transport equipment>
FIG. 1 is a perspective view showing an example of a semiconductor manufacturing apparatus including a wafer transfer apparatus according to Embodiment 1 of the present invention.

As shown in FIG. 1, the semiconductor manufacturing apparatus 1 includes a wafer transport unit (wafer transport device) 100, a wafer processing unit 200, and an operation console 300. The wafer transport unit 100, the wafer processing unit 200, and the console 300 can communicate with each other via a network (not shown). Here, the user of the semiconductor manufacturing apparatus 1 is, for example, a worker at a semiconductor manufacturing factory or a host computer system at the semiconductor manufacturing factory.

Each unit included in the semiconductor manufacturing equipment 1 automatically transfers and processes the wafer WAF (FIG. 2) by inputting commands, control parameters, etc. from the operation console 300 to the computer system installed in each unit. conduct. Each unit then transmits the wafer WAF transfer results, processing results, etc. to the operator console 300 and the host computer system.

《Wafer transport unit》
The wafer transport unit 100 is a unit that transports wafers to be processed (transported) to and from the wafer processing unit 200, which is a host device. The wafer WAF is carried into and out of the wafer transport unit 100 using a cassette, which is a wafer storage container. The loading and unloading of the cassette is performed via the opening/closing mechanism 103 shown in FIG.

A wafer transfer robot provided in the wafer transfer unit 100 takes out the wafer to be processed from the cassette and transfers it to the wafer processing unit 200. When the processing in the wafer processing unit 200 is completed, the wafer transfer robot receives the processed wafer from the wafer processing unit 200 and stores it in a cassette. The processed wafers are carried out of the wafer transport unit 100 together with the cassette. The configuration of the wafer transfer unit 100 will be explained in detail later.

《Wafer processing unit》
The wafer processing unit 200 is a unit that processes wafers transferred from the wafer transfer unit 100. The processing in the wafer processing unit 200 includes various processing such as, for example, forming semiconductor elements on a wafer and measuring dimensions of elements formed on the wafer.

The wafer processing unit 200 includes a processing section that processes wafers, a computer system that controls the processing section, a power supply, and the like (all not shown). A computer system includes a processor such as a CPU, and a RAM and ROM that are directly accessed by the processor. Further, the computer system may also include a control board and the like in addition to these.

For example, when the wafer processing unit 200 is a length measurement SEM (Scanning Electron Microscope), the processing section includes an electron gun, a stage, a vacuum exhaust device, and the like. The computer system measures the dimensions of the fine pattern formed on the wafer by controlling the processing unit based on commands sent from the console 300. The dimensional measurement results of the fine pattern are transmitted to the console 300 via the network.

The specifications of each functional unit constituting the semiconductor manufacturing apparatus 1 are standardized. Therefore, a user can configure the semiconductor manufacturing apparatus 1 by arbitrarily combining units compliant with the same standard. In this embodiment, a wafer processing unit 200 having the same standard as the wafer transport unit 100 is used.

Note that the wafer processing unit 200 may be one that performs only one item of processing, or may be one that can execute multiple items of processing. Further, although only one processing unit is shown in FIG. 1, a plurality of wafer processing units 200 may be included in the semiconductor manufacturing apparatus 1.

《Operation console》
The operation console 300 is a functional block that operates each unit of the semiconductor manufacturing apparatus 1. As shown in FIG. 1, the console 300 includes a computer system 310, a monitor 320, and a keyboard 330 as an input device. The console 300 may also include a mouse and a control switch (both not shown) as input devices.

The computer system 310 includes, for example, a processor such as a CPU, and a RAM and ROM that are directly accessed by the processor. In addition to these, the computer system 310 may also include a control board and the like. Further, the operation console 300 is connected to the computer system 310 and includes a storage device, a communication device, etc. (not shown).

The computer system 310 controls each element included in the console 300, gives instructions to the wafer transport unit 100 and the wafer processing unit 200, sends and receives various information between the wafer transport unit 100 and the wafer processing unit 200, and the like. Further, the computer system 310 displays a GUI (Graphical User Interface) on the monitor 320, inputs and outputs information via the GUI, and communicates with a host computer system of a semiconductor manufacturing factory. The GUI software is stored in computer system 310 or a storage device.

The operator inputs commands to the computer system 310 using an input device (keyboard 330, mouse, control switch, etc.), a touch panel of the monitor 320, etc., on the GUI displayed on the monitor 320.

Information such as wafer transfer results and processing results received from the wafer transfer unit 100 and the wafer processing unit 200 is displayed on the GUI of the monitor 320 and is also stored in the computer system 310 or a storage device. When the host computer system of the semiconductor manufacturing factory is the user of the semiconductor manufacturing equipment 1, the host computer system communicates with the computer system 310 via the network, and sends and receives information such as instructions, wafer transfer results, and processing results. I do.

The storage device has a storage area for storing programs such as a control program for controlling the operator console 300, and a storage area for storing information such as wafer transport results and processing results received from the wafer transport unit 100 and the wafer processing unit 200. . The communication device is a functional block that communicates with the wafer transport unit 100, wafer processing unit 200, and host computer system via the network.

Computer system 310 needs to have the high reliability required for semiconductor manufacturing lines. Therefore, it is desirable that the computer system 310 be a highly durable and stable computer system that can operate 24 hours a day, 365 days a year, such as an industrial computer.

<Wafer>
The wafer WAF is a disk-shaped plate member made of, for example, silicon (Si) or gallium arsenide (GaAs), which is also called gallium arsenide.

The diameter of the wafer WAF is available in a plurality of sizes within the range of, for example, 25 mm to 450 mm. The thickness of the wafer WAF is, for example, approximately 280 μm to 1000 μm. The wafer WAF is formed with an orientation flat, a notch, etc. for positioning the direction of the disk. The dimensions of the orientation flat and notch are also standardized. Some of these dimensions are standardized by each association or organization in each country. For example, the dimensions of silicon wafers with diameters of 200 mm and 300 mm are standardized based on standards.

On the other hand, if the diameter is 150 mm or less, for example, there are wafers whose thickness does not comply with the standard. This is to ensure the functionality of the element. Furthermore, the allowable wafer thickness varies by standard. For example, one standard specifies that the thickness of a wafer with a diameter of 150 mm is 625±15 μm. but. Another standard specifies that the thickness of a wafer WAF with a diameter of 150 mm is 675±20 μm. Therefore, the maximum difference in wafer thickness between these standards is 85 μm.

<Configuration of wafer transport unit>
Next, the configuration of the wafer transfer unit 100 will be explained. FIG. 2 is a top view showing an example of the configuration of the wafer transfer device according to Embodiment 1 of the present invention. 3 and 4 are side views showing an example of the configuration of a wafer transfer unit according to Embodiment 1 of the present invention.

As shown in FIGS. 2 to 4, the wafer transfer unit 100 includes a cassette mounting table 110, a pre-aligner 120, a wafer transfer robot 130, a camera 140, a computer system 190, and the like.

The cassette mounting table 110 is a mounting table on which a cassette CAS is placed via the opening/closing mechanism 103, and has a function as a transfer port through which the wafer transfer robot 130 accesses the wafer WAF. A plurality of cassette mounting tables 110 (two in FIG. 2) may be provided within the wafer transport unit 100. In this case, a plurality of cassettes CAS can be placed within the wafer transport unit 100.

Although not shown, the cassette mounting table 110 is provided with a positioning block that allows the cassette CAS to be positioned with good reproducibility within the mounting surface on which the cassette CAS is mounted.

A worker or a cassette transport robot in a semiconductor manufacturing factory can place the cassette CAS on the cassette mounting table 110 while pressing the cassette CAS against the positioning block.

Further, the cassette mounting table 110 is provided with sensors, switches, etc. that detect the position and presence of the cassette CAS, the protrusion of the wafer WAF from the cassette CAS, and the like. The computer system 190 checks whether the cassette CAS is normally placed on the cassette mounting table 110, stores the history of the presence or absence of the cassette CAS, and ejects the wafer WAF from the cassette CAS based on information from sensors, switches, etc. Detection, etc.

Further, the cassette mounting table 110 is provided with a reader that reads the barcode and serial number pasted on the cassette CAS. The host computer system of the semiconductor manufacturing factory can manage the cassette CAS by reading the barcode and serial number pasted on the cassette CAS using a reader.

The pre-aligner 120 is a device that measures the amount of eccentricity of the wafer WAF accommodated in the cassette CAS placed on the cassette mounting table 110, and aligns the orientation flat and notch based on the measurement result. The eccentricity measurement results for each wafer WAF are transmitted to the computer system 190 and held within the computer system 190, or stored in a storage device.

The wafer transfer robot 130 is a device that transfers the wafer WAF between the wafer transfer unit 100 and the wafer processing unit 200. The wafer transfer robot 130 includes an arm 132, a hand 134, and a mapping sensor 136, as shown in FIGS. 2 to 4. A hand 134 for vacuum suction or gripping the wafer WAF is connected to one end of the arm 132, and a mapping sensor 136 is connected to the other end opposite to the hand 134. Note that the number of arms may be one or three or more.

For example, the wafer transfer robot 130 receives the eccentricity measurement result of each wafer WAF from the computer system 190, corrects the eccentricity based on the received eccentricity measurement result, and aligns the orientation of the cassette CAS. Take out the wafer WAF from the wafer. Then, the wafer transfer robot 130 transfers the taken-out wafer WAF to the upper port 203. In this way, the wafer WAF is transferred between the wafer transport unit 100 and the wafer processing unit 200 via the upper port 203.

The wafer transfer robot 130 takes out the processed wafer WAF returned from the wafer processing unit 200 from the upper port 203. Then, the wafer transfer robot 130 stores the wafer WAF taken out from the upper port 203 into the cassette CAS. At this time, the processed wafer WAF is, in principle, accommodated in the same slot of the same cassette CAS as before processing.

The horizontal drive axes of the wafer transfer robot 130 are an X-axis in a direction from the cassette mounting table 110 toward the upper port 203 in FIG. 2, and a Y-axis perpendicular to the X-axis. The vertical drive axis of the wafer transfer robot 130 is the Z axis. Further, the wafer transfer robot 130 can rotate within the XY plane around the Z axis, and the rotation angle is represented by Θ. The wafer transfer robot 130 performs a wafer WAF transfer operation by moving (including rotation) the arm 132 and the hand 134 along these drive axes.

Although FIGS. 2 to 4 illustrate an orthogonal drive type robot as the wafer transfer robot 130, the present invention is not limited to such a configuration. The wafer transfer robot 130 may have any configuration as long as it has the function of transferring the wafer WAF, such as an articulated robot in which multiple axes operate in conjunction with each other.

The mapping sensor 136 is a sensor that senses the wafer WAF housed in the cassette CAS. Specifically, the mapping sensor 136 senses the position of the wafer WAF accommodated in the cassette CAS.

As the mapping sensor 136, for example, a transmission type sensor using light is used. As shown in the figure, the mapping sensor 136 includes a light projector 136a that emits position detection light for detecting the position of the wafer WAF, and a light receiver 136b that receives the position detection light emitted from the light projector 136a. The light projector 136a emits position detection light toward the light receiver 136b, and when the light receiver 136b receives the position detection light, it outputs a light reception signal as a sensing signal. Furthermore, when the light receiver 136b is not receiving the position detection light, it may output an inverted signal of the light reception signal as the sensing signal.

The light reception signal and the inversion signal are transmitted, for example, to the computer system 190, and the computer system 190 performs position detection processing of the wafer WAF based on the light reception signal (and the inversion signal). Note that the mapping sensor 136 is not limited to such a configuration, and a reflective sensor that detects a position based on reflected position detection light or the like may be used.

Note that although FIGS. 2 to 4 show an example in which the mapping sensor 136 is mounted on the wafer transfer robot 130, the mapping sensor 136 may also be mounted on the cassette mounting table 110, a cassette opener (not shown), etc. may be done.

The camera 140 is installed at a predetermined position in the casing of the upper port 203 facing the cassette mounting table 110 in the wafer transport unit 100 . The camera 140 is an imaging device that generates a captured image including the cassette mounting table 110, the cassette CAS placed on the cassette mounting table 110, and the wafer WAF accommodated in the cassette CAS. In FIG. 2, cameras 140a (140) and 140b (140) are provided corresponding to cassette mounting tables 110a (110) and 110b (110), respectively.

The camera 140 may have the functions of a visible light camera (color camera), an infrared camera, and a polarizing camera, or may have a plurality of these functions. An infrared camera generates a temperature distribution image (infrared image) of a photographed area as a thermograph. Based on the infrared image, computer system 190 can measure the temperature inside the cassette CAS.

When equipped with an infrared camera function, the camera 140 includes an infrared camera or an optical system with high infrared transmittance. When equipped with a polarization camera function, the camera 140 includes a polarization camera and an optical system that controls polarization.

The polarizing camera is used when the cassette CAS is black, transparent, etc. and difficult to identify, and generates a captured image (polarized image) in the polarization state of light in the imaging area. When an infrared image or a polarized image is used, it may be easier to detect the edge or shape of the wafer WAF or cassette CAS than a visible light image.

The camera 140 and optical system 144 are optimally selected depending on the color and material of the cassette CAS. Although it depends on the image sensor of the camera 140 used and the spectral sensitivity indicating the sensitivity to wavelength of the optical system 144, the optical system 144 may be equipped with, for example, a filter for wavelength selection, a polarizing plate, a wavelength plate, etc. A captured image of the imaging region in the state or an infrared captured image may be generated. In that case, the optical system 144 is configured to transmit only light in a specific wavelength range using a spectroscopic function or a filter.

The camera 140 is equipped with an optical system 144 (FIG. 4) in which an optical path 148 is adjusted so that the captured image includes the cassette mounting table 110, the cassette CAS, and the cassette CAS. Note that the optical system of the camera 140 may be adjusted to include at least the cassette CAS placed on the cassette mounting table 110 and the wafer WAF accommodated in the cassette CAS.

The optical system 144 may have an enlarged photographing function using optical zoom. In order to realize the enlarged photographing function, the camera 140 is provided with a lens movable section that switches lenses and adjusts the focal length. Additionally, camera 140 may include a digital zoom function. Therefore, the enlarged image may be generated by optical zoom or may be generated by digital zoom without changing the optical system.

Further, the camera 140 may have a video shooting function. The video data is stored in the storage device in the wafer transport unit 100, the computer system 190, etc. for a predetermined period of time. This makes it possible for the operator and the host computer system of the semiconductor manufacturing factory to record the loading and unloading of the cassette CAS, and the unloading and storage of the wafer WAF with respect to the cassette CAS.

When an abnormality occurs, by displaying the recorded video on the monitor 320 and visually checking the situation at the time of the abnormality, it is possible to investigate the cause of the abnormality, and take precautions and take measures to prevent recurrence. becomes possible.

The abnormalities mentioned here include, for example, cases where the cassette CAS is placed diagonally due to a human error by an operator, or cases where the wafer WAF pops out and is damaged when the cassette CAS is placed on the cassette mounting table 110, etc. including.

The illumination system 142 is provided at a position facing the cassette CAS, and illuminates an area including the cassette CAS. The illumination system 142 can, for example, switch the illumination light ON/OFF in accordance with the timing of photographing by the camera 140. The illumination system 142 may be a flash or other type of illumination mounted on the camera 140, or may be provided separately from the camera 140. The optical path 146 of the illumination system 142 is adjusted so that the cassette mounting table 110, the cassette CAS, and the wafer WAF are optimally illuminated.

When the camera 140 includes an infrared camera or an optical system with high infrared transmittance, the illumination system 142 emits infrared light. This makes it possible to accurately detect the cassette CAS and wafer WAF even when the cassette CAS is made of a material or color that is difficult to detect passively or when the factory lighting is dark.

Further, when the camera 140 includes a polarization camera or an optical system capable of observing the polarization state, the illumination system 142 illuminates the light with the polarization state controlled. In addition, the illumination system 142 can easily select the polarization state for shape identification by emitting illumination light that always passes through a predetermined optical path or polarized illumination light controlled by a laser. It becomes possible to detect the wafer WAF with high accuracy.

The computer system 190 controls each element in the wafer transport unit 100 in accordance with the instructions from the computer system 310, and transfers the wafer WAF to and from the wafer processing unit 200, takes out and stores the wafer WAF in the cassette CAS, etc. Perform processing.

The computer system 190 includes, for example, a processor that performs various calculations and analyses, a robot controller that controls the wafer transfer robot 130, a pre-aligner controller that controls the pre-aligner 120, and the like. The robot controller and the pre-aligner controller may be implemented on a processor by executing a program. Further, the computer system 190 may include a power source for driving these devices.

The wafer transfer unit 100 includes a communication device, and communicates with the computer system 310 of the operator console 300 and the computer system of the wafer processing unit 200 via the communication device, and sends and receives commands, signals, information, and the like.

Note that the computer system 310 may not be provided on the console 300 in some cases. In this case, the computer system 190 of the wafer transport unit 100 may include functionality in the computer system 310. That is, in this case, the computer system 190 serves as a host computer and controls the entire semiconductor manufacturing apparatus 1.

<Cassette configuration>
FIG. 5 is a front view showing an example of the configuration of the cassette. The cassette CAS is provided with a plurality of stages of wafer guides (hereinafter also referred to as grooves) on which wafers WAF are placed, and can accommodate a plurality of wafers WAF. The wafer guide is also referred to as a slot, a pocket, or the like.

The cassette CAS is also called a wafer storage container, FOUP (Front Opening Unify Pod), open cassette, pod, or the like. Cassette CAS has also been standardized.

A certain standard specifies that the pitch between slots (PIT_1, PIT_2) corresponding to a wafer with a diameter of 150 mm is 4.76±0.25 mm. Further, the pitch between slots corresponding to a wafer with a diameter of 200 mm is defined as 6.35±0.38 mm. In this way, the distance between wafers when housed in the cassette CAS is narrower for a 150 mm diameter wafer than for a 200 mm diameter wafer.

Furthermore, in a cassette CAS that supports wafers with a diameter of 150 mm or less, the pitch between slots is narrower than in a cassette CAS that supports wafers with a diameter of 200 mm or 300 mm.

Even within the same cassette CAS, the pitch between the slots may have a large difference in size, that is, a large variation. In a cassette CAS having a diameter of 150 mm or less, the pitch between the slots is narrow, so that dimensional variations account for a large proportion of the available space in which the hand 134 of the wafer transfer robot 130 can operate.

The position of the slot in the height direction (Z-axis direction) of the cassette CAS placed on the cassette mounting table 110 may differ between cassettes made by the same manufacturer or cassettes made by different manufacturers. For example, the position (height H1) from the bottom of the cassette CAS to the first slot may differ between slots. In this way, if the cassette CAS is different and the height at which the wafer WAF is transported is different, the risk of wafer transport increases.

<Cassette and wafer position detection method>
Next, a method for detecting the positions of cassettes and wafers using captured images and the like will be described. When processing a wafer WAF, the position of the cassette CAS and the position of each wafer WAF within the cassette CAS are specified.

FIG. 6 is a flow diagram showing an example of the position detection method according to Embodiment 1 of the present invention. In the example of FIG. 6, steps S10 to S120 are performed when detecting the positions of the cassette and wafer.

《Step S10》
First, in step S10, mapping information of the wafer WAF accommodated in the cassette CAS is acquired. When acquiring mapping information, mapping processing is performed to detect the position of the wafer WAF accommodated in the cassette CAS. In the mapping process, the position of the wafer WAF in the Z-axis direction is detected by sensing the wafer WAF housed in the cassette CAS by moving the mapping sensor 136 in the Z-axis direction (hereinafter also referred to as mapping operation). be done.

FIG. 7 is a diagram showing an outline of the mapping operation and an example of the wafer position detection results. FIG. 7 illustrates a case where three wafers WAF are accommodated in the cassette CAS and the positions of these wafers WAF are detected.

If the cassette CAS is normally placed on the cassette mounting table 110 and the wafer WAF is not ejected from the cassette CAS by the sensor of the cassette mounting table 110, the computer system 190 of the wafer transport unit 100 will transfer the wafer. The robot 130 is driven to move the mapping sensor 136 to the front of the cassette CAS. At this time, the mapping sensor 136 is placed at a predetermined home position (HP) that is preset for the mapping operation.

Thereafter, the computer system 190 drives the wafer transfer robot 130 to move the mapping sensor 136 from top to bottom along the Z-axis so that only the position of the wafer WAF is detected, that is, without interfering with the cassette CAS. drive. Note that the mapping operation at this time may be performed from bottom to top, but in order to improve reproducibility, it is preferable to always perform the mapping operation in a fixed direction.

The mapping process will be described in more detail. The right side diagram of FIG. 7 shows the position of the wafer WAF detected by the mapping operation, mapping range setting information, and the like. The wafer transfer robot 130 is taught mapping range setting information in the Z direction from the console 300 . The mapping range setting information indicates a safe range in which the mapping sensor 136 does not physically come into contact with the cassette CAS, the cassette mounting table 110, the casing of the wafer transport unit 100, etc. during the mapping operation. As the mapping range setting information, for example, an upper limit position (+Limit) and a lower limit position (-Limit) of the mapping operation are set. These mapping range setting information are set in advance by the operator.

The mapping sensor 136 performs mapping processing by moving between an upper limit position (+Limit) and a lower limit position (-Limit). Note that since there is a space around the cassette CAS, the same upper limit value and lower limit value of the mapping range setting information can be used regardless of the type of cassette CAS. Therefore, it is desirable that the mapping range setting information once taught be stored within the wafer transport unit 100 (for example, in the storage device or computer system 190). This allows the next mapping process to be started immediately.

During the mapping operation, the mapping sensor 136 is switched on and off near the position where the wafer WAF is accommodated. Specifically, first, when the light receiver 136b is receiving the position detection light from the light emitter 136a, the mapping sensor 136 is ON, and the light receiver 136b is not receiving the position detection light from the light emitter 136a. At this time, the mapping sensor 136 is OFF.

If the mapping sensor 136 has not been lowered to the upper surface position (height) of the wafer WAF, the light receiver 136b receives the position detection light and outputs a light reception signal (sensing signal). On the other hand, when the mapping sensor 136 moves down to the upper surface position (Upper) of the wafer WAF, the position detection light is blocked by the wafer WAF. Therefore, the light receiver 136b cannot receive the position detection light and cannot output a light reception signal. However, the light receiver 136b may output an inverted signal (sensing signal) of the light reception signal. Then, when the mapping sensor 136 moves down to the lower surface position (Lower) of the wafer WAF, the light receiver 136b receives the position detection light again and resumes outputting the light reception signal (sensing signal).

In the example of FIG. 7, the upper surface position (Upper1) and lower surface position (Lower1) of the wafer WAF1 accommodated in the lower stage of the cassette CAS are detected. The upper surface position (Upper2) and lower surface position (Lower2) of the wafer WAF2 accommodated in the middle stage of the cassette CAS are detected. The upper surface position (Upper3) and lower surface position (Lower3) of the wafer WAF3 accommodated in the upper stage of the cassette CAS are detected.

The wafer transfer robot 130 transmits encoded values to the computer system 190 when the mapping sensor 136 reaches the upper and lower positions of the wafer WAF. For example, the wafer transfer robot 130 sends to the computer system 190 an encoded value corresponding to the top surface position when the mapping sensor 136 is switched from ON to OFF, and an encoded value corresponding to the bottom surface position when the mapping sensor 136 is switched from OFF to ON. Send to. Computer system 190 retains or stores the received encoded values in storage.

Note that the encoded value is a control value for controlling the attitude of the wafer transfer robot 130. In this embodiment, a control value for moving wafer transfer robot 130 in the Z-axis direction is used as an encoded value.

The wafer transfer robot 130 can recognize the number of wafers WAF accommodated in the cassette CAS based on the number of times the encoded value is transmitted. In the example of FIG. 7, since there are three sets of upper surface positions (Upper) and lower surface positions (Lower), wafer transfer robot 130 transmits the encoded value six times. Therefore, the wafer transfer robot 130 can recognize that there are three wafers WAF. For example, the above-mentioned information is included in the mapping information.

The computer system 190 can grasp the amount of movement of the wafer transfer robot 130 (mapping sensor 136) in the Z-axis direction based on the encoded value sent from the wafer transfer robot 130. Thereby, the computer system 190 can detect the position of the wafer WAF housed in the cassette CAS on the Z axis based on the encoded value. In this way, the computer system 190 obtains mapping information of the wafer WAF based on the sensing signal transmitted from the mapping sensor 136.

Further, the computer system 190 can calculate the thickness of each wafer WAF from the encoded values corresponding to the upper surface position (Upper) and the lower surface position (Lower). Thereby, the computer system 190 can determine whether the wafer WAF is normally accommodated in the cassette CAS. Such determination results are also included in the mapping information.

FIG. 8 is a diagram illustrating the arrangement of wafers including the case where an abnormality is detected in the thickness of the wafer. The cassette CAS in FIG. 8 accommodates a plurality of wafers (WAF11 to WAF17). The wafers WAF11 to WAF12 on the upper end side and the wafers WAF13 to WAF14 on the lower end side are shown in a case where they are normally accommodated in the cassette CAS.

On the other hand, wafers WAF15 to WAF17 show examples in which the thickness of the wafers WAF is abnormal. Specifically, wafers WAF15 to WAF16 are shown in which two wafers are accommodated in the same slot. The wafer WAF 17 is shown as an example of staggered storage in which the wafers WAF 17 are accommodated in different slots on the left and right sides. If an attempt is made to transport the wafer WAF in such an abnormal state, the wafer WAF may be damaged or broken.

Note that if the wafer WAFs are accommodated in all slots of the cassette CAS, the distance between adjacent wafer WAFs can be calculated from the upper surface position (Upper) and the lower surface position (Lower), and the pitch between the slots can be understood. It is possible. However, the wafer WAF is not necessarily accommodated in all slots of the cassette CAS. For this reason, accommodating wafer WAFs in all slots of the cassette CAS and performing mapping processing in order to perform calibration takes time and effort, and is not efficient. Therefore, as will be described later, the shape of the cassette CAS and the pitch between the slots are detected using the camera 140. Such information may also be included in the mapping information.

《Step S20》
In step S20, the computer system 190 retreats the wafer transfer robot 130 so as not to block the optical path 148 of the camera 140 and the optical path 146 of the illumination system 142.

《Step S30》
In step S30, the computer system 190 sets photographing conditions for the camera 140. The computer system 190 performs optical zooming such as autofocus, switching lenses, switching filters, switching wavelength plates, switching between a visible light camera and an infrared camera, in response to instructions from an operator or a host computer system, for example. Settings and position adjustments of the optical system 144 necessary for photographing, such as setting exposure time, are performed.

The computer system 190 also sets and adjusts photographing conditions related to the illumination system 142. The photographing conditions related to the illumination system 142 include, for example, the amount of illumination, switching between infrared light and visible light, illumination time, illumination position, and the like. Furthermore, when the illumination light has polarization such as a laser beam, switching of the polarization of the illumination light is also included in the photographing conditions.

The operator identifies each cassette CAS carried into the wafer transport unit 100. For this reason, a check box for selecting a cassette CAS may be provided in advance on the GUI displayed on the monitor 320, and imaging conditions may be input or selected for each selected cassette CAS.

Further, when step S30 is executed again after step S70, which will be described later, the computer system 190 may sequentially set other imaging conditions prepared in advance in a prespecified order.

《Step S40》
In step S40, the camera 140 photographs an area including the cassette CAS, wafer WAF, and cassette mounting table 110, or a partial area thereof, in accordance with a command from the computer system 190. The captured image is held in the RAM of the computer system 190 and then stored in the storage device of the wafer transport unit 100.

Further, the captured image may be transmitted to the computer system 310 via the network, held in the RAM of the computer system 310, and then stored in the storage device of the operator console 300. The captured images transmitted to the computer system 310 are sequentially displayed on the monitor 320, and the operator can monitor the captured images displayed on the monitor 320.

《Step S50》
In step S50, the computer system 190 performs image processing on the captured image. For example, an algorithm that can identify the shapes of the wafer WAF, cassette CAS, and cassette mounting table 110 is used for the image processing. Specifically, the edges and shapes of the wafer WAF, cassette CAS, and cassette mounting table 110 are detected using algorithms such as a Laplacian filter, Sobel filter, Canny filter, and binarization. However, other image processing may be performed.

In step S50, image processing may be performed multiple times using different algorithms, or image processing may be performed only using an algorithm selected based on knowledge obtained in advance.

Note that the computer system 190 may perform image processing for display on the monitor 320. For example, when the operator selects the type of image to be displayed on the monitor 320, the computer system 190 may display an image with changed colors or an image of only the wafer WAF so that the selected type of image is immediately displayed. , thermography images, etc., may be subjected to image processing in advance for display.

《Step S60》
In step S60, image wafer information is acquired based on the captured image. For example, the computer system 190 detects edges and shapes from the captured image after image processing, and detects the wafer WAF by pattern recognition.

Specifically, the diameter of the wafer can be easily estimated from the size of the cassette CAS. As a result, if the detected edge is a horizontal line with a length close to the diameter of the wafer WAF, this edge can be easily identified as belonging to the wafer WAF. Therefore, the computer system 190 can determine that such an edge belongs to the wafer WAF, and can recognize the diameter, thickness, and number of wafers WAF. Then, the computer system 190 detects the position (top surface position, bottom surface position) of the wafer WAF from the detected edge. These pieces of information are included in the image wafer information obtained through image processing. In this manner, computer system 190 obtains image wafer information based on the captured image.

Further, the computer system 190 detects whether the edge of the wafer WAF is horizontal, and determines whether the wafer WAF is normally accommodated in the cassette CAS. If an abnormality is detected, such as slots being inserted diagonally at different levels as shown in FIG. 8, a warning is displayed in step S120, which will be described later. Further, information regarding such an abnormality may also be included in the image wafer information.

《Step S70》
In step S70, the computer system 190 determines whether the mapping information obtained in step S10 matches the image wafer information obtained in step S60 based on the captured image after image processing. The computer system 190 generates mapping information and image wafer information regarding items such as the presence or absence of a wafer WAF, the number of wafers, the thickness, the accommodation state including the presence or absence of an abnormality, the accommodation position (height), and the number of stages of accommodation slots. Compare with. Note that the mapping information and the image wafer information may be compared using only some of these items.

Note that the captured image may be divided into a plurality of regions, and the mapping information and the image wafer information may be compared for each region. An example of how to divide the area is to divide the captured image sequentially from the bottom to the top.

If the mapping information and the image wafer information do not match (NO), the process moves to step S80. On the other hand, if the mapping information and the image wafer information match (YES), the process moves to step S90.

《Step S80》
If the mapping information and the image wafer information do not match, a retry is performed to change the imaging conditions and reacquire the image wafer information. However, since wafer processing is delayed if retries are repeated, an upper limit value is set for the number of retries.

In step S80, computer system 190 determines whether the number of retries that have already been performed is a preset upper limit number of retries. If the number of retries is smaller than the upper limit number of retries (NO), the processes of steps S30 to S70 are executed again, and the image wafer information after changing the imaging conditions is obtained and the mapping information and the image wafer information are compared. Note that the number of retries is defined, for example, by the number of times it is determined in step S80 that the number of retries is smaller than the upper limit number of retries.

On the other hand, if the number of retries is the upper limit number of retries (YES), the process moves to step S120. Then, the computer system 190 outputs an error indicating that the number of retries is the upper limit number of retries to the computer system 310, and causes the monitor 320 to display the error.

《Step S90》
In step S90, the computer system 190 determines whether the wafer WAF is accommodated in the cassette CAS based on the comparison result between the mapping information and the image wafer information in step S70. If it is determined that the wafer WAF is accommodated in the cassette CAS (YES), the process moves to step S100. On the other hand, if it is determined that the wafer WAF is not accommodated in the cassette CAS (NO), the process moves to step S110.

《Step S100》
In step S100, the computer system 190 determines whether there is a wafer WAF whose storage location is unknown. If the same cassette CAS is placed in the same location until the wafer WAF is removed from the cassette CAS and re-accommodated, the computer system 190 determines that the destination of the wafer WAF being transported or processed is not unknown. Make a judgment (NO).

On the other hand, when the wafer WAF is taken out from the cassette CAS and is being transported or processed, the cassette CAS is removed from the cassette mounting table 110 by a worker or a cassette transport robot in a semiconductor manufacturing factory, and then the cassette CAS is placed in the same place. If so, wafer transfer robot 130 or computer system 190 cannot determine whether the later cassette CAS is the same as the previous cassette CAS. Therefore, the computer system 190 determines that the storage location of the wafer WAF being transported or processed is unknown (YES).

Furthermore, even if the power is restored after being cut off due to a power outage or pressing an emergency stop button during wafer processing, the wafer transfer robot 130 or the computer system 190 will be able to retrieve the cassette CAS detected before and after the power was cut off. It is not possible to determine whether they are the same. Therefore, the computer system 190 determines that the storage location of the wafer WAF being transported or processed is unknown (YES).

In each cassette CAS, the slot positions in the Z-axis direction may differ or vary. Therefore, when the situation described here occurs, the computer system 190 determines that the storage location of the wafer WAF is unknown and ensures safety.

In recent years, semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) have come to be used for small-diameter wafers with a diameter of 200 mm or less. Further, semiconductor elements formed on a wafer WAF are becoming multilayered. For these reasons, the thickness of wafers is no longer just compliant with standards. As the wafer becomes thicker, the margin of movement of the wafer transfer robot 130 within the cassette CAS decreases. Therefore, the risk of wafer transportation increases.

If it is determined that the storage location of the wafer WAF being transported or processed is not unknown (NO), the process moves to step S120. On the other hand, if it is determined that the storage location of the wafer WAF being transported or processed is unknown (YES), the process moves to step S110.

《Step S110》
In step S110, the computer system 190 measures the dimensions of the cassette CAS.

The captured images before and after the image processing described in step S40 and step S50 are used to measure the dimensions of the cassette CAS. FIG. 9 is a diagram showing an example of a captured image used in the cassette dimension measurement process. FIG. 10 is a diagram showing an enlarged image of FIG. In FIG. 10, the lower left area of the cassette CAS in FIG. 9 is enlarged and displayed using optical zoom, digital zoom, or the like. Furthermore, the images in FIGS. 9 and 10 are captured images after, for example, the edges of the cassette CAS have been detected and grayscale color processing has been performed to facilitate the measurement of the dimensions of the cassette CAS.

Regarding the image generation in FIG. 10, although it depends on the optical system used, for example, if one side of the outer shape of the cassette CAS is 200 mm and one side of the outer shape of the cassette CAS is imaged on 3000 pixels arranged in one direction, the resolution is is approximately 0.07 mm. The system is designed and the selection of optical zoom and digital zoom is determined by the required safety and price.

The cassette mounting table 110 is provided with a reference scale 112 and a reference slit 114 for dimension measurement. The reference scale 112 is an arbitrary optical scale from about several mm to about several μm. The computer system 190 measures the dimensions of the dimension measurement target of the captured image based on the reference scale. The computer system 190 detects the reference pixel number by, for example, converting the actual distance between the graduations of the reference scale 112 into the number of pixels of the captured image. Then, the computer system 190 calculates the actual dimensions of the dimension measurement target by detecting the number of pixels of the dimension measurement target in the captured image.

Although it is not necessary to perform calibration frequently, for example, when moving parts of the optical system are operated, or when a warning or error occurs, calibration is performed before performing dimension measurement processing. This is desirable.

Based on the reference slit 114, the computer system 190 matches the position (height) of the wafer transfer robot 130 in the Z-axis direction with the position (height) of the wafer transfer robot 130 in the Z-axis direction of the captured image. Reference slit 114 is scanned by mapping sensor 136. The upper surface position (Upper) and lower surface position (Lower) of the reference slit 114 are taught and stored in the computer system 190 in advance. Note that the scale of the reference scale 112 corresponding to the lower surface position (Lower) or upper surface position (Upper) of the reference slit 114 may be stored in the computer system 190.

Further, the computer system 190 determines whether the wafer transfer robot 130 is at the home position of the mapping sensor 136 based on the distance between the lower surface position (Lower) of the reference slit 114 and the home position (HP) of the mapping sensor 136. By storing the positional relationship (distance, etc.) between the wafer and the reference slit 114, it is possible to align the position photographed by the camera 140 with the absolute position of the driving position of the wafer transfer robot 130.

For example, the worker can measure the dimensions of any location by specifying two arbitrary points using a mouse or the like while referring to the captured image shown on the GUI displayed on the monitor 320. .

When the dimensions of the cassette CAS are automatically measured, the computer system 190 measures the dimension between both ends of the cassette CAS and the dimension between both edges of the wafer WAF. This makes it possible to estimate the diameter of the wafer WAF. Further, the computer system 190 calculates the center line CEN of the cassette CAS shown in FIG. 9 from the dimensions of both ends of the cassette CAS in the captured image. The center line CEN is used to determine whether the cassette CAS is normally placed on the cassette mounting table 110.

The computer system 190 also detects the center position SLOT_CEN of the slot, which is a groove in the wafer guide. For example, the computer system 190 measures the distances (eg, D1, D2, and D3) between the top and bottom surfaces of the wafer guide, and detects the center position of each distance. Then, the computer system 190 calculates the distance D10 between each detected center position SLOT_CEN and the lower surface position of the reference slit 114.

By using these calculated values, the computer system 190 can recognize the position where the wafer transfer robot 130 accommodates the wafer WAF in the cassette CAS, and can safely accommodate the wafer WAF in the first slot.

Although the first stage slot has been described here, the computer system 190 may calculate the center position SLOT_CEN and the distance D10 from the bottom surface position of the reference slit 114 for each slot in a plurality of stages. When calculating the distance D10 between the center position SLOT_CEN and the lower surface position of the reference slit 114 for multiple slots, the wafer transfer robot 130 can accommodate the wafer WAF in any slot.

In addition, when you want to transport the wafer WAF more safely or when you want to shorten the time required for dimension measurement processing, the center position SLOT_CEN and the lower surface position of the reference slit 114 can be The distance D10 may be calculated. If it is close to the reference scale 112 and the reference slit 114, dimensional measurement errors will be reduced and safety will be improved. Furthermore, since the number of slots for dimension measurement is reduced, the time required for dimension measurement can be shortened.

Further, the operator can carry the cassette CAS into the wafer transfer unit 100 for the purpose of measuring the dimensions of the cassette CAS. By performing dimension measurement processing for a plurality of cassettes CAS in advance, step S110 can be skipped as appropriate.

《Step S120》
In step S120, the processing results from steps S10 to S110 are displayed on the monitor 320 of the operation console 300, including alarms and warnings. Furthermore, if the user is a higher-level computer system in a semiconductor manufacturing factory, these processing results are sent to the higher-level computer system. Note that the processing results of each step may be transmitted to the operator console 300 or the host computer system at any time and stored in a storage device or the like. In this case, processing results etc. may be displayed on the monitor 320 at any time.

When the process of step S120 is completed, the flowchart of FIG. 6 ends. Thereafter, the wafer WAF is transported, processed, and the like.

<Captured image and GUI>
Next, an example of a captured image including before and after image processing and a GUI screen displayed on the monitor 320 will be described. FIG. 11 is a diagram illustrating a captured image. FIG. 11 shows a plurality of types of captured images after image processing.

The image PIC_1 is a captured image (or moving image) and a wafer image WAFa based on the mapping information (step S10). The image PIC_2 is a composite display of the wafer image WAFa on a thermography image taken with an infrared camera of the camera 140, with the image of the cassette CAS hidden. Image PIC_2a is an image showing the temperature scale of image PIC_2. Image PIC_2a clearly informs the operator that the shading on the screen indicates the temperature, and is displayed as a set with image PIC_2.

The image PIC_3 is a composite display of the wafer image WAFa with an image in which the edges of the cassette CAS are emphasized. Wafer WAF and cassette CAS can be easily identified by painting images of unnecessary areas in a certain color (for example, white). Image PIC_4 is more simply a display of only the wafer image WAFa that has undergone edge detection and pattern recognition. These images are prepared in advance, and the operator can switch the displayed image by selecting an image using a pull-down menu on the PIC or the like.

FIG. 12 is a diagram illustrating a GUI. FIG. 12 exemplifies the GUI when the image PIC_1 is displayed on the monitor 320, and is the GUI of the selection screen of the wafer WAF to be processed.

When the operator uses the mouse to move the cursor CUR near an arbitrary wafer image WAFa, the wafer image WAFa blinks. In FIG. 12, the 24th slot from the bottom is selected. When the mouse is clicked in this state, the wafer image WAFa is switched to the highlighted image. At this time, the wafer WAF is provisionally selected as a processing target, and a check box BOX_1 is displayed with a lead line. Further, when the check box BOX_1 is clicked or when the wafer image WAFa is clicked again, a check is entered, and this wafer WAF is placed in a processing reservation state.

Note that when a plurality of wafer images WAFa are selected, similar operations are repeatedly performed. In this case, the corresponding wafers WAF are sequentially processed according to preset rules such as the order of clicks and the order of placement in the cassette CAS.

The wafer check box BOX_2 is a box that shows an overview of the processing reservation status of the wafer WAF. In the wafer check box BOX_2, check boxes corresponding to the number of wafers WAF detected in step S70 of FIG. 6 are arranged. Specifically, in FIG. 11 or 12, wafers WAF (WAFa) are accommodated in the first to second, tenth to twelfth, and twenty-fourth slots from the bottom, respectively. Therefore, checkboxes corresponding to each row of slots are displayed in the wafer checkbox BOX_2.

Since the wafer image WAFa in the 24th slot from the bottom was checked earlier, the checked state is also reflected in the wafer check box BOX_2. Note that although the corresponding slot stage number is displayed next to each check box in the wafer check box BOX_2, the display of the slot stage number can be omitted as appropriate.

Further, even if the corresponding wafer checkbox in the wafer checkbox BOX_2 is checked without selecting the wafer image WAFa, it is possible to place the corresponding wafer WAF in the processing reservation state.

The wafer transport unit 100 can manage the number of wafers to be processed from the bottom. Therefore, a number indicating the number of wafers from the bottom may be displayed next to each check box in wafer check box BOX_2. In the example of FIG. 12, the wafer WAF in the 24th slot from the bottom is the sixth wafer from the bottom, so "6" is displayed in the corresponding check box.

In addition, in the example of FIG. 12, since the operator can visually determine the number of wafers WAF from the bottom, the number of wafers from the bottom displayed next to each check box in wafer check box BOX_2 A mode may be provided in which the number indicating whether the wafer is a second wafer is omitted.

As a result, an operator can make a processing reservation for a wafer WAF without being aware of the number of slot stages or the like. Furthermore, display or non-display can be selected for the wafer check box BOX_2.

While the selected wafer WAF is being processed, the corresponding wafer image WAFa, the corresponding parts of the check box BOX_1 and the wafer check box BOX_2 are displayed in a different color from normal times, so that it is clearly displayed that the process is in progress. .

Display or non-display of processed images and the like can also be selected for each type. The operator can arbitrarily customize the GUI configuration to make it easier to use.

Furthermore, when a plurality of wafers WAF are densely stored in the cassette CAS, the operator can, for example, click two diagonal corners of the rectangular area ARE_1 with a mouse to create the area ARE_1 in FIG. It can be enlarged and displayed as shown in . This makes it possible to identify each wafer WAF, and prevents mistakes in selecting a wafer WAF.

FIG. 13 is an enlarged view of the GUI shown in FIG. 12. In FIG. 13, the aforementioned area ARE_1 is displayed in an enlarged manner, and wafer images WAFa corresponding to each wafer WAF accommodated in three consecutive slots are displayed for easy selection.

When the cursor CUR is moved near the central wafer image WAFa, this wafer image WAFa blinks. Since the processing related to the selection of the wafer WAF to be processed and the like has already been described, detailed explanation will be omitted.

The operator can arbitrarily select the type of image to be enlarged and displayed. Unlike FIG. 12, FIG. 13 shows an enlarged display of the image PIC_3 of the cassette CAS, which has undergone edge processing through image processing. This makes it easier to visually recognize the cassette CAS and wafer WAF.

FIG. 14 is a diagram illustrating a GUI on which a thermography image is displayed. The GUI shown in FIG. 14 includes an image PIC_2 that is a composite display of the thermography image and the wafer image WAFa, and an image PIC_2a that shows the temperature scale. Note that it is possible to display the cassette image CASa, the wafer image WAFa, and the cassette image CASa in a composite manner on the thermography image.

The color and temperature range of the temperature scale can be changed arbitrarily. The temperature scale may be set so that a temperature range is assigned by automatically determining the maximum value and minimum value, or may be set so that a predetermined temperature range is always assigned. When the cursor CUR is moved to the image PIC_2a, the temperature (for example, 30° C.) at the position selected by the cursor CUR is displayed near the image PIC_2a on the temperature scale.

Temperature information at each location measured using image PIC_2 is stored in a memory or storage device within the computer system 190, 310. Furthermore, by clicking on multiple points in the image PIC_2, it is also possible to measure the temperatures at multiple locations at the same time. Furthermore, if a clear button (not shown) is clicked, the temperature information acquired so far will be erased.

According to the image PIC_2 in FIG. 14, the operator can confirm at a glance that the temperature near the center of the top is high and the temperature at both ends of the bottom is low. By fixing the temperature scale, the operator can start processing the wafer WAF while keeping the temperatures of the wafer WAF and cassette CAS substantially the same.

Further, by storing a predetermined set temperature in the computer system 190, the computer system 190 can determine that the temperature of the wafer WAF or cassette CAS is abnormal and issue an alarm. In the semiconductor manufacturing apparatus 1, the temperature of the wafer WAF often affects the processing results, so it is a great advantage that the operator can easily visually confirm that the temperature of the wafer WAF is the same.

FIG. 15 is a diagram illustrating a GUI that displays a warning. FIG. 15 shows a GUI when the wafer WAF accommodated in the cassette CAS is in an abnormal state. Abnormal conditions include a case where a plurality of wafers WAF are accommodated in the same slot in an overlapping manner, a case where a wafer WAF is accommodated obliquely in a slot at a different level, and the like.

In FIG. 15, a warning is displayed for the wafer image WAFa, the cassette image CASa, and the areas ARE_11 and ARE_12 where an abnormal state has occurred. The areas ARE_11 and ARE_12 may be displayed in any color (for example, yellow, red, etc.) as a warning display, or may be displayed blinking.

Furthermore, the word "Warning" may be displayed near the cassette image CASa as a warning display. These allow the operator to recognize at a glance that there is an abnormality in the wafer WAF housed in the cassette CAS. Further, from the displayed image, the operator can directly and easily visually identify whether two wafers WAF are accommodated in the cassette CAS in an overlapping manner or whether the wafers WAF are accommodated diagonally.

In the semiconductor manufacturing process, if it is known in advance that the thickness of the wafer WAF is thicker than the standard, an allowable range for the thickness of the wafer WAF is set in advance so that a warning due to the thickness of the wafer WAF is not displayed. Is possible.

In the wafer check box BOX_11 in FIG. 15, the number of slot stages is not displayed. In FIG. 15, since the accommodating state of the wafer WAF is abnormal, "x" is displayed in the checkbox corresponding to the bottom wafer WAF and the checkbox corresponding to the top wafer WAF, and these The checkbox cannot be selected.

A wafer image WAFa corresponding to a wafer WAF that is accommodated in a normal state can be selected, except when the wafer WAF cannot be safely transported because it is accommodated in an abnormal state.

FIG. 16 is a GUI showing a state in which a wafer can be accommodated in the first slot from the bottom after the cassette measurement process shown in FIG. In FIG. 16, a wafer image WAFb is displayed at the accommodating position of the wafer WAF in the first slot from the bottom. This wafer image WAFb is displayed in a different color from the normal wafer image WAFa and the wafer image corresponding to the wafer WAF being processed.

The operator moves the cursor CUR to the vicinity of the wafer image WAFb and clicks it. Then, a check box BOX_21 is displayed near the wafer image WAFb. Then, by clicking the wafer image WAFb again or checking the check box BOX_21, it is possible to determine the storage location of the wafer WAF whose storage location is unknown.

On the GUI, a wafer thickness input box BOX_22 for inputting the thickness of the wafer is displayed together with a check box BOX_21. The standard wafer thickness is input into the wafer thickness input box BOX_22 by default. If the wafer thickness is different from the default value, the operator can modify the value in the wafer thickness input box BOX_22. Thereby, the wafer transfer robot 130 can be operated in consideration of the thickness of the wafers accommodated in the cassette CAS, and the wafer WAF can be transferred more safely.

FIG. 17 is a diagram showing an example in which the number of slot stages of the cassette displayed in the wafer check box in FIG. 12 is calculated by image processing. The computer system 190 uses the cassette image CASa generated by edge detection to detect each pixel data on the line L1 of the groove portion of the cassette CAS or the average value of pixel data around the line L1 as a line waveform WAV. Here, pixel data will be explained. In the case of a color camera, the gradation data of each color of RGB is pixel data, and in the case of a gray scale, the gradation data of black and white shading is pixel data.

Next, the computer system 190 detects the number of slots in the cassette CAS by setting a threshold on the line waveform WAV and counting the ON/OFF regions based on the threshold. Then, by calculating the center value of the ON/OFF region for each region, it is possible to determine the storage location of the wafer WAF.

Here, a case has been described in which the computer system 190 uses the line L1 on the left side of the cassette CAS to determine the storage location for the wafer WAF, but the storage location for the wafer WAF may also be determined using the line L2 on the right side. . Further, the computer system 190 may determine the storage location of the wafer WAF using both lines L1 and L2.

This makes it possible to safely accommodate the wafer WAF even if no wafer WAF is accommodated and a cassette CAS with dimensions different from the taught content is placed.

<Main effects of this embodiment>
According to this embodiment, the computer system 190 compares the mapping information of the wafer WAF in the cassette CAS with the image wafer information based on the captured image. Then, if the mapping information and the image wafer information do not match, the computer system 190 performs a retry to compare the new image wafer information based on the captured image with changed imaging conditions. According to this configuration, it is possible to accurately detect the position, thickness, etc. of the wafer WAF in the cassette CAS, and it is possible to reduce the risk of wafer transportation.

Furthermore, according to the present embodiment, if the number of retries is the upper limit number of retries, an error is output. According to this configuration, it is possible to stop the position detection process for the wafer WAF that is the target of the error, and it is possible to shorten the time required for the position detection process. Furthermore, since the wafer WAF that is the target of the error is not processed, it is possible to reduce the risk of wafer transportation.

Further, according to the present embodiment, the mapping information and the image wafer information include the position of the wafer. According to this configuration, it is possible to reduce the risk of transporting the wafer WAF within the cassette CAS.

Further, according to the present embodiment, a composite image (PIC_1, etc.) is generated, which is a composite display of a captured image after image processing and a wafer image (WAFa, etc.), and the composite image is monitored as a selection screen for a wafer to be transported. 320. According to this configuration, the situation inside the cassette CAS is displayed on the monitor 320 in real time, and the user can easily select the wafer WAF to be processed.

Further, according to this embodiment, the computer system 190 measures the temperature inside the cassette CAS based on the infrared image. According to this configuration, it is possible to manage the temperature of the wafer WAF at the start of processing.

Further, according to the present embodiment, the computer system displays a composite image of the infrared image and the wafer image on the monitor 320. According to this configuration, the user can check the internal temperature of the cassette CAS in real time.

Further, according to the present embodiment, camera 140 includes a polarization camera or an optical system that controls polarization, and generates a polarization image. According to this configuration, even if the cassette CAS is black, transparent, or otherwise difficult to identify, it is possible to recognize the shape, etc. of the cassette CAS.

Further, according to the present embodiment, an illumination system 142 is provided that illuminates the area including the cassette CAS. According to this configuration, even if the wafer transport unit 100 is placed in a dark place, it is possible to take an image in a bright situation.

Further, according to the present embodiment, when camera 140 includes an infrared camera or an optical system with high infrared transmittance, illumination system 142 emits infrared light. According to this configuration, a clear infrared image is generated.

Further, according to the present embodiment, when camera 140 includes a polarization camera or an optical system that controls polarization, illumination system 142 illuminates light with a controlled polarization state. According to this configuration, a clear polarized light image is generated.

Further, according to the present embodiment, computer system 190 matches the position of wafer transfer robot 130 with the position of wafer transfer robot 130 in the captured image based on reference slit 114 . According to this configuration, it is possible to maintain position detection accuracy based on the captured image.

Further, according to the present embodiment, the computer system 190 measures the dimensions of the dimension measurement target in the captured image based on the reference scale 112. According to this configuration, it is possible to improve the accuracy of dimension measurement for a dimension measurement target such as a cassette CAS or wafer WAF using a captured image. Furthermore, it is possible to improve the detection accuracy of the diameter and thickness of the wafer WAF.

Further, according to the present embodiment, even if the mounted cassette CAS is unintentionally replaced with another one and the dimensions of the cassette CAS change before and after the replacement, the image taken by the camera 140 and the By analyzing the wafer WAF and cassette CAS obtained from processing, the movable area of the wafer transfer robot 130 can be determined, making it possible to safely transfer the wafer WAF.

Further, according to the present embodiment, even if the diameter of the wafer WAF accommodated in the cassette CAS and the size of the cassette CAS are different, the wafer WAF and the cassette CAS obtained from the image photographed by the camera 140 and the image processing are different. Since the movable region of the wafer transfer robot 130 can be determined through analysis, it is possible to safely transfer wafers WAF having a plurality of preset diameter sizes.

Further, according to the present embodiment, the operator can visually observe the housing state of the wafer WAF, the mounting state of the cassette CAS, the posture, the temperature distribution, etc. from the images and moving images displayed on the monitor 320. . Thereby, the operator can grasp the abnormal state of the wafer WAF or cassette CAS, and can quickly take measures such as reaccommodating the wafer WAF or reloading the cassette CAS.

Further, according to the present embodiment, the operator can visually confirm the number of wafer WAF storage stages from the images and videos displayed on the monitor 320 by the camera 140, so that the necessary settings for data exchange are necessary. It is possible to make a selection for processing or transporting a wafer WAF without being aware of the number of slots in the cassette CAS in which the wafer WAF is stored.

Furthermore, according to the present embodiment, the worker can visually view the wafer WAF from the images and moving images displayed on the monitor 320 by the camera 140, so that if the wafer WAF has a plurality of preset diameter sizes and thicknesses, It becomes possible to select a wafer WAF without being aware of the diameter or thickness of the wafer WAF.

Furthermore, according to the present embodiment, even if an abnormality occurs, the operator or the host computer system uses the recording function of the camera 140 to check the state at the time of the abnormality using the saved video. be able to. Furthermore, by investigating the cause of the abnormality occurrence, it becomes possible to take measures to prevent recurrence.

(Embodiment 2)
Next, a second embodiment will be described. In this embodiment, the wafer WAF is recognized only by image processing. In the following, explanations of parts that overlap with those in Embodiment 1 will be omitted in principle.

FIG. 18 is a flow diagram illustrating an example of a position detection method according to Embodiment 2 of the present invention. FIG. 18 is similar to FIG. 6, and differences from FIG. 6 will be described. In the example of FIG. 18, when detecting the positions of the cassette and wafer, steps S20 to S60, S270 to S280, and S90 to S120 are performed.

In step S270, computer system 190 determines whether the image wafer information was appropriately acquired in step S60. The computer system 190 appropriately processes image wafer information regarding items such as the presence or absence of a wafer WAF, the number of wafers, the thickness, the accommodation state including the presence or absence of an abnormality, the accommodation position (height), and the number of stages of accommodation slots. Determine whether the data was successfully acquired. For example, if the original captured image is blurred, edges cannot be detected even after image processing, and the position and number of wafer WAFs cannot be accurately detected, the image wafer information may be It is determined that the data could not be obtained.

Note that also in this embodiment, the captured image may be divided into a plurality of regions, and the mapping information and the image wafer information may be compared for each region. An example of how to divide the area is to divide the captured image sequentially from the bottom to the top.

If the image wafer information cannot be properly acquired (NO), the process moves to step S280. On the other hand, if the image wafer information has been appropriately acquired (YES), the process moves to step S90.

In step S280, if the image wafer information cannot be acquired appropriately, a retry is performed to change the imaging conditions and reacquire the image wafer information. However, since wafer processing is delayed if retries are repeated, an upper limit value is set for the number of retries. Step S280 is similar to step S60 in FIG. 6, so detailed explanation will be omitted. If the number of retries is smaller than the upper limit number of retries (NO), the processes of steps S30 to S60 and S270 are executed again.

On the other hand, if the number of retries is the upper limit number of retries (YES), the process moves to step S120. Then, the computer system 190 outputs an error indicating that the number of retries is the upper limit number of retries to the computer system 310, and causes the monitor 320 to display the error.

Note that in this embodiment, mapping processing is not performed. Therefore, the mapping sensor 136 shown in FIG. 2 etc. does not need to be provided.

According to this embodiment, the computer system 190 detects the position of the wafer WAF in the cassette CAS based on the image wafer information without performing mapping processing. According to this configuration, it is possible to reduce the time required for position detection by the time required for mapping processing. Furthermore, since a mapping sensor is no longer required, the device configuration is simplified.

Further, according to the present embodiment, when the computer system 190 determines that the image wafer information could not be appropriately acquired, it performs a retry to acquire new image wafer information based on the captured image with changed imaging conditions. According to this configuration, it is possible to accurately detect the position, thickness, etc. of the wafer WAF in the cassette CAS, and it is possible to reduce the risk of wafer transportation.

Furthermore, according to the present embodiment, if the number of retries is the upper limit number of retries, an error is output. According to this configuration, it is possible to stop the position detection process for the wafer WAF that is the target of the error, and it is possible to shorten the time required for the position detection process. Furthermore, since the wafer WAF that is the target of the error is not processed, it is possible to reduce the risk of wafer transportation.

Note that the present invention is not limited to the embodiments described above, and includes various modifications. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. . Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations. Note that each member and relative size shown in the drawings are simplified and idealized in order to explain the present invention in an easy-to-understand manner, and may result in a more complicated shape when mounted.

1... Semiconductor manufacturing equipment, 100... Wafer transfer unit, 130... Wafer transfer robot, 136... Mapping sensor, 140... Camera, 142... Lighting system, 190, 310... Computer system, 200... Wafer processing unit, 300... Operation console, CAS...cassette, WAF...wafer

Claims (13)

a wafer transfer robot that takes out a wafer from a wafer storage container in which a plurality of wafer guides are provided and stores the wafer in the wafer storage container;
a mapping sensor that senses the position of the wafer contained in the wafer storage container;
a camera that is provided at a position facing the wafer storage container and that generates a captured image that includes the wafer storage container;
acquiring mapping information of the wafer in the wafer container based on a sensing signal transmitted from the mapping sensor; acquiring image wafer information based on the captured image after image processing; and acquiring the mapping information and the image wafer information. a computer system that compares the
Equipped with
Wafer transport equipment. The wafer transfer device according to claim 1,
When the computer system determines that the mapping information and the image wafer information do not match,
The camera generates a captured image with changed shooting conditions,
The computer system performs a retry to compare the mapping information and new image wafer information based on the captured image with changed imaging conditions.
Wafer transport equipment. The wafer transport device according to claim 2,
The computer system performs the retry if the number of retries is smaller than the upper limit number of retries, and outputs an error if the number of retries is the upper limit number of retries.
Wafer transport equipment. The wafer transfer device according to claim 1,
the mapping information and the image wafer information include the position of the wafer;
Wafer transport equipment. The wafer transfer device according to claim 1,
The computer system generates a composite image that is a composite display of the captured image after image processing and the wafer image based on the mapping information, and displays the composite image on a monitor as a selection screen for the wafer to be transported.
Wafer transport equipment. The wafer transfer device according to claim 1,
The camera includes an infrared camera or an optical system with high infrared transmittance, and generates an infrared image,
The computer system measures the temperature inside the wafer storage container based on the infrared image.
Wafer transport equipment. The wafer transfer device according to claim 6,
The computer system generates a composite image that is a composite display of the infrared image and the wafer image based on the mapping information, and displays the composite image on a monitor.
Wafer transport equipment. The wafer transfer device according to claim 1,
The camera includes a polarization camera or an optical system that controls polarization, and generates a polarization image.
Wafer transport equipment. The wafer transfer device according to claim 1,
an illumination system provided at a position facing the wafer storage container and illuminating a region including the wafer storage container;
Wafer transport equipment. The wafer transfer device according to claim 9,
When the camera includes an infrared camera or an optical system with high infrared transmittance,
The illumination system emits infrared light,
Wafer transport equipment. The wafer transfer device according to claim 9,
When the camera includes a polarization camera or an optical system that controls polarization,
The illumination system illuminates with light whose polarization state is controlled.
Wafer transport equipment. The wafer transfer device according to claim 1,
comprising a wafer mounting table on which the wafer storage container is mounted;
A reference slit is provided in the wafer mounting table,
The computer system matches the position of the wafer transfer robot with the position of the wafer transfer robot in the captured image based on the reference slit.
Wafer transport equipment. The wafer transfer device according to claim 1,
comprising a wafer mounting table on which the wafer storage container is mounted;
A reference scale for calibration is provided on the wafer mounting table,
The computer system measures dimensions of a dimension measurement target in the captured image based on the reference scale.
Wafer transport equipment.

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