System and method of monitoring an environmental parameter along a predetermined route

A monitoring system has a vehicle and a monitoring device. The vehicle is movable along a predetermined route, and the monitoring device is detachably mounted to the vehicle. The vehicle has a photonic device configured to read position information according to detection of a positioning tag positioned at a predetermined position along the predetermined route. The monitoring device has a sensor configured to monitor an environmental parameter and a controller communicatively coupled to the sensor and the photonic device. The controller is configured to record the monitored environmental parameter along the predetermined route and the position information.

TECHNICAL FIELD

The present disclosure relates to semiconductor manufacturing, and more particularly, to a system and method of monitoring an environmental parameter along a predetermined route.

BACKGROUND

During manufacturing of semiconductor integrated circuits (ICs), semiconductor wafers are subjected to multiple processing steps at different processing equipments. For example, to complete the fabrication of an IC chip, various steps of deposition, cleaning, ion implantation, etching, and/or passivation steps are generally carried out in different processing equipments. Therefore, fabrication facilities generally include transportation systems such as an automated material handling system (AMHS) for transporting the semiconductor wafers among the processing equipments.

Further, in a fabrication facility, a carefully controlled environment when transporting the semiconductor wafers is important due to the delicate nature of the chips. Abnormalities in vibration, temperature, humidity, or level of contamination along the route of transportation increase the risk of unexpected particles or features formed on the wafers and decrease the yield rate of the manufacturing process. Therefore, there is a need for monitoring one or more environmental parameters when transporting the semiconductor wafers.

DETAILED DESCRIPTION

FIG. 1Adepicts a portion of a monitoring system100for monitoring an environmental parameter along a predetermined route according to an embodiment. A track102is positioned to define the predetermined route along which the monitoring system100is movable. The monitoring system100comprises a vehicle110configured to move along track102and a monitoring device120detachably mounted to vehicle110and configured to monitor an environmental parameter. In some embodiments, the monitoring system100is an AMHS adapted to perform the monitoring function. In some embodiments, the monitoring system100monitors one or more environmental parameters including vibration, temperature, humidity, or level of contamination along the route of transportation, or any combination thereof.

FIG. 1Bis a cross-sectional view as seen if looking at (imaginary) plane A of the monitoring system100depicted inFIG. 1A. In at least one embodiment, track102is a guide rail mounted to a ceiling104in a fabrication facility, and vehicle110is movably mounted to the guide rail. In some other embodiments, track102comprises a rail, a magnetic strip, a conveyor, or a combination thereof. Depending on the type of track and vehicle, in some embodiments, the track is mounted on a floor or an elevated structure. Vehicle110is configured to carry a payload and move along the track. The payload, in some exemplary applications, comprises a Front Opening Unified Pod (FOUP) designed to hold one or more semiconductor wafers. In at least one embodiment, the payload is monitoring device120.

Further, a positioning tag122is positioned at a predetermined position along the predetermined route and vehicle110comprises a photonic device124configured to read position information from positioning tag122according to detection of positioning tag122. In some embodiment, positioning tag122is positioned on or adjacent to the track102. In at least one embodiment, positioning tag122comprises a barcode and the photonic device124is a barcode reader for detecting the barcode on the positioning tag122. In some other embodiments, positioning tag122comprises an optical feature such as a barcode, a text, a figure, or a combination thereof and photonic device124is configured to be responsive to all or a portion of visible lights, infrared lights, or ultraviolet lights, or any combination thereof, that it received either directly from a light source or by reflection.

FIG. 2depicts an exemplary layout of predetermined routes and positioning tags according to an embodiment. A plurality of positioning tags202athrough202isimilar to the positioning tag122(FIG. 1B) are positioned at a plurality of predetermined positions along the routes or tracks212athrough212f. In some embodiments, the position information acquired by the vehicle110is sent to a traffic control center for controlling the traffic on the tracks, i.e., the movement of at least one vehicle110on the tracks. For example, at a specific time in at least one embodiment, there is more than one vehicle110mounted on and mobile along the tracks212a-212fin order to transport semiconductor wafers to different processing equipment in the fabrication facility. The traffic control center directs vehicles to a corresponding destination processing equipment while avoiding collisions between the vehicles. Further, in order to monitor an environmental parameter in the fabrication facility along the tracks212a-212f, at least one vehicle110carries a monitoring device120instead of one or more FOUPs holding semiconductor wafers or other payload types. In some embodiments, the vehicle110with the monitoring device120moves along a predetermined route for monitoring the environmental parameter along the predetermined route.

In some embodiments, on top of the positioning tags202a-202inecessary for traffic control, more positioning tags are placed along the tracks212a-212fat sections where higher spatial resolution for monitoring the environmental parameter is preferred. For example, in an embodiment in which the vibration of the vehicle110along the tracks212a-212fis monitored, more positioning tags are positioned at positions where track assemblies are jointed, where there is a track junction, or where there is a curved track.

FIG. 3depicts a system diagram of a monitoring system300for monitoring an environmental parameter along a predetermined route according to an embodiment. Similar to the monitoring system100(FIGS. 1A and 1B), the monitoring system300comprises a vehicle310configured to move along the predetermined route and a monitoring device330detachably mounted to the vehicle310. In addition, in at least one embodiment, the monitoring system300further comprises a log server350configured to receive the recorded monitored environmental parameter and the recorded position information from the monitoring device330. The log server350comprises a display device352configured to display a visualized presentation of the predetermined route, the recorded monitored environmental parameter, and/or the recorded position information. In some embodiments, the log server350further comprises a microcontroller354electrically coupled to the display device352to control the operation of the display device352and a storage356electrically coupled to the microcontroller354to store the recorded monitored environmental parameter received from the monitoring device330.

The vehicle310is configured to transport the monitoring device330and move along the predetermined route, such as a track102(FIG. 1B). In some embodiments, vehicle310comprises a photonic device312, a controller314communicatively coupled to the photonic device312, and a communication module316communicatively coupled to the photonic device312and the controller314. The photonic device312reads position information according to detection of a positioning tag positioned at a predetermined position along the route or track. The communication module316transmits the position information to the monitoring device330.

In at least one embodiment, the controller314manages the operation of the photonic device312and the communication module316. Further, in some embodiments, the controller314also controls a motor of the vehicle310in order to drive the vehicle310along the route or track based on a predetermined traffic control functionality programmed in a storage device of the vehicle310or instructions issued by a traffic control center to the vehicle310.

In at least one embodiment, the monitoring device330comprises a sensor332, a controller334, a storage device338, and a display340. The controller334is communicatively coupled to the sensor332, the storage device338, and the display340to manage the operation of the monitoring device330. In some embodiments, the controller334comprises a general-purpose microcontroller, a processor, or an application-specific integrated circuit (ASIC) and the storage device338comprises a hard drive, a flash drive, a DRAM, an SRAM, or an applicable storage device such as a computer readable medium storing instructions for execution by the controller334.

The sensor332monitors the environmental parameter. In at least one embodiment, the sensor332is a vibration sensor for monitoring a vibration along the route or track of the vehicle310to which the monitoring device330is attached. For example, in some embodiments, the sensor332is a tri-axial vibration sensing device. The tri-axial vibration sensing device continuously, or repetitively according to a preset timing pattern, monitors vibrations and decomposes them into x-axis, y-axis, and z-axis components. In some embodiments, the sensor332is a vibration sensing device capable of recording vibrations according to less or more than three axes. In some other embodiments, the sensor332is configured to detect vibration, temperature, humidity, contamination levels in the air, noise, bio-hazardous particles, or any combination thereof. In at least one embodiment, the sensor332is a camera configured to acquire still images or video clips.

In some embodiments, the controller334records the monitored environmental parameter and stores the parameter in the storage device338. For example, the controller334receives the vibration information from the sensor332and records the vibration information in a time-based manner with a plurality of time tags along a time axis. In some embodiments, each stored vibration data point is associated with a time tag. Further, in some embodiments, the controller334is communicatively coupled with the photonic device312through communication module336. In some embodiments, the controller334receives the position information from the vehicle310and stores the position information in the storage device338. In at least one embodiment, while recording the monitored environmental parameter and the position information, the controller334also associates the position information with at least one of the plurality of time tags.

The communication module336of monitoring device330communicates with the communication module316of vehicle310. In some embodiments, communication modules316and336are coupled in a wired manner. For example, when mounting the monitoring device330onto the vehicle310, as depicted inFIG. 1B, the communication modules316and336are electrically coupled through a USB connection, an IEEE-1394 connection, a RS-232 connection, an optical fiber, or another applicable connection, either serial or parallel. In some embodiments, communication module316is electrically connected to a set of connecting pins, and communication module336is electrically connected to a set of connecting pads, where the connecting pins and corresponding connecting pads form electrical contacts with each other when the monitoring device330is mounted onto the vehicle310.

In yet some other embodiments, the communication modules316and336are communicatively coupled in a wireless manner. For example, in at least one embodiment, the communication module316and the communication module336are BLUETOOTH communication modules capable of communicating with each other according to a BLUETOOTH communication protocol. In some embodiments, the communication module316and the communication module336are wireless LAN modules, infrared communication modules, laser transceivers, or any applicable wireless communication modules according to industry protocols or proprietary protocols.

In some embodiments, a log server350comprising a display device352configured to communicate with the monitoring device330in order to receive the recorded monitored environmental parameter and the recorded position information. In at least one embodiment, the monitoring device330is removed from the vehicle310after being transported along a predetermined route by the vehicle310, and then the log server350is communicatively coupled to the monitoring device330in a wired or wireless manner, such as the exemplary communication methods presented above for communication modules316and336. In at least another embodiment, the log server350is communicatively coupled to the monitoring device330in a wireless manner and receives the recorded monitored environmental parameter and position information while the monitoring device330remains mounted to and transported by the vehicle310.

The display device352displays the visualized presentation of the monitoring results received from the monitoring device330. In some embodiments, the display device352is an LCD monitor. Further, in at least one embodiment, the monitoring device330also comprises a display device340for showing the operational status of the monitoring device330and/or the readings of the monitored environmental parameter. In some embodiments, the display device340also displays the visualized presentation of the monitoring results of the monitoring device330. In at least some embodiments, the display device340is an LCD monitor or an LED array.

FIG. 4is a flow chart of a process for monitoring an environmental parameter according to an embodiment. The flow chart is merely exemplary, and additional functions may be performed before, after, or in between the exemplary steps. Further, in some embodiments, the exemplary functionality is performed in a different order.

In step402, a vehicle310carrying a monitoring device330is driven along a predetermined route for monitoring an environmental parameter. In Step404, position information is read from a positioning tag by a photonic device312according to detection and/or scanning of the positioning tag positioned at a predetermined position along the predetermined route. In step406, the environmental parameter is monitored by a monitoring device330detachably mounted to the vehicle. In some embodiments, the monitoring device330is configured to detect vibration, temperature, humidity, contamination levels in the air, noise, bio-hazardous particles, or any combination thereof. In at least one embodiment, the monitoring device330is configured to acquire still images or video clips.

In step408, the monitored environmental parameter and the position information are recorded by the monitoring device330along the predetermined route. In some embodiments, monitoring device330records the vibration in a time-based manner with a plurality of time tags and associates the position information with at least one of the plurality of time tags.

In step410, a display device340or352displays a visualized presentation of the predetermined route, the recorded monitored environmental parameter, and/or the recorded position information is shown by.

FIG. 5Ais a chart of a recorded environmental parameter versus a time axis according to an embodiment. In some embodiments, when the monitoring device330starts to record the monitored environmental parameter, the monitored results are recorded in a time-based manner. In at least some embodiments, each monitored result is associated with a time tag generated by the monitoring device330. For example, in at least one embodiment, a vibration of the vehicle330is monitored by the monitoring device330. The monitoring device330continuously monitors the vibration and associates the results with time tags. Therefore, the relation between recorded monitored vibration versus a time axis is depicted inFIG. 5A. However, in some applications, because more than one vehicle may move along the tracks or routes at the same time, the vehicle310carrying the monitoring device330is ordered by the traffic control center to stop, speed up, or slow down from time to time. That is, the vehicle310does not necessarily travel at a constant speed. Thus, merely from the information depicted inFIG. 5A, the spatial relationship between the recorded monitored environmental parameter and its corresponding positions along the predetermined route cannot be properly determined.

FIG. 5Bis a chart of a recorded environmental parameter versus a time axis in combination with recorded position information associated with a plurality of time tags according to an embodiment. In some embodiments, the monitoring device330also receives position information from the vehicle and associates the received position information with time tags. In some embodiments, the read position information is translated into a text code for recording. As such, the spatial relationship between the recorded monitored environmental parameter and the corresponding positions along the predetermined route are determinable from the recorded monitored environmental parameter and the position information (such as the Position Tags #1-#4depicted inFIG. 5B).

FIG. 6is a diagram of an exemplary visualized presentation of predetermined routes with dots depicted to identify positions of abnormality. In order to better identify the positions along the predetermined route where abnormality is suggested by the monitored environmental parameter and thus further actions may be necessary, the display device610displays a visualization of the recorded monitored environmental parameter. In at least one embodiment, the display of visualized presentation of the monitoring results is performed by the log server350executing a program or a set of instructions stored in a storage device356of the log server350.

In some embodiments, a layout of the predetermined route as well as other possible routes, such as tracks612a-612g, is depicted on the display device610. At least one data point in the recorded monitored environmental parameter that will be identified in the visualized presentation is selected. For example, if the monitored environmental parameter is vibration of monitoring device330while mounted to the vehicle310, a data point in the recorded monitored environmental parameter having a vibration value greater than a predetermined threshold (such as 0.5G for example) can be selected as a selected data point associated with a location of an abnormal occurrence.

Further, a position on the layout of the predetermined route can be selected according to the recorded position information and the selected data point. Numerical calculations, such as an interpolation or an extrapolation to determine a position corresponding to the selected data point, are performed in order to more accurately determine the position. Then, the position corresponding to the location of abnormal occurrence is identified on the layout of the predetermined route displayed on the display device610. Based on the visualized presentation, further acts can be taken to cure the identified abnormality. For example, if the vibration at a specific position along a track exceeds the predetermined threshold, a nearby track assembly, track joint or track junction is examined, adjusted, or replaced, to ease the vibration.

In some embodiments, the recorded monitored environmental parameter is screened by two or more threshold values. For example, when monitoring the vibration of the vehicle along the predetermined route, a first group of data points having values greater than 0.5G and a second group of data points having values greater than 0.4G, but no greater than 0.5G, are selected. Subsequently, the positions on the depicted layout of the tracks612a-612gare determined, and these positions are identified on the display device610with predetermined symbols616a-616dand618a-618b. In at least one embodiment, positions corresponding to the first group of data points are depicted with red dots such as dots616a-616d, and positions corresponding to the second group of data points are depicted with yellow dots such as dots618a-618b. In some embodiments, instead of colored dots, the positions corresponding to the first and second groups of data points are depicted by dots with shading or patterns, colored segments, or arrows pointing to corresponding positions on the layout of tracks612a-612g.