Wafer frame sorter and stocker

A wafer sorting and stoking system provides automated storage and retrieval of wafer frames carrying semiconductor wafers. A wafer frame cassette is received at a transfer port from a transfer system. A robot arm retrieves the wafer frames from the cassette and stores each wafer frame in a respective storage slot in one of a plurality of storage towers. The storage location of each wafer frame is recorded. Each wafer frame can be selectively retrieved and loaded into a wafer frame cassette by the robot arm for further processing.

BACKGROUND

Technical Field

The present disclosure relates to the field of semiconductor processing. The present disclosure relates more particularly to sorting and stocking wafer frames carrying semiconductor wafers.

Description of the Related Art

Fabrication of integrated circuits is typically accomplished by performing a large number of processing steps on semiconductor wafers. The processing steps typically result in the formation of a large number of transistors in highly complex arrangements in conjunction with a semiconductor substrate. The processing steps also result in the formation of dielectric layers, metal interconnects, vias, plugs, and other integrated circuit structures and components.

When processing of the semiconductor wafer is substantially complete, the semiconductor wafer is loaded onto a wafer frame. After the semiconductor wafer is loaded onto the wafer frame, the semiconductor wafer is diced. After dicing, the semiconductor wafer may remain on the wafer frame during storage or transport. Sorting and storing wafer frames before and after dicing can be problematic due to the potential of misplacement and breakage

DETAILED DESCRIPTION

In the following description, many thicknesses and materials are described for various layers and structures within an integrated circuit die. Specific dimensions and materials are given by way of example for various embodiments. Those of skill in the art will recognize, in light of the present disclosure, that other dimensions and materials can be used in many cases without departing from the scope of the present disclosure.

FIG. 1is a block diagram of a wafer frame stoking and sorting system100. The system includes a robot arm102, storage towers104, a control system106, and a transfer port108, according to various embodiments. The robot arm102, the storage towers104, the control system106, and the transfer port108work together to remove wafer frames116from a wafer frame cassette114and to store the wafer frame cassettes. Each wafer frame116carries a semiconductor wafer118.

The wafer frame sorting and stocking system100avoids the drawbacks of human sorting and stocking of wafer frames116. In particular, the wafer frame sorting and stocking system100provides automated transport, sorting, tracking, and retrieval of wafer frames116. This eliminates the need for humans to handle the wafer frames116or to manually track the location of individual wafer frames116.

After the semiconductor wafers118are processed and are ready for dicing, each individual semiconductor wafer118is placed on a respective wafer frame116. Each wafer frame116typically includes a metal ring (seeFIG. 7). Each wafer frame116also includes an adhesive membrane such as a tape or another material stretched across the interior of the ring. The semiconductor wafer118is placed on the adhesive membrane. Accordingly, each wafer frame116carries a semiconductor wafer118on an adhesive membrane stretched in the interior defined by the metal ring. Wafer frames116can have shapes, membranes and configurations other than those described above without departing from the scope of the present disclosure.

Groups of wafer frames116are loaded into a wafer frame cassette114for transport. Each wafer frame cassette114includes a plurality of wafer frame slots. Each wafer frame slot holds an individual wafer frame116. In one example, each wafer frame cassette114holds between 10 and 15 wafer frames116. A wafer frame cassette114can hold fewer or more wafer frames without departing from the scope of the present disclosure.

After the semiconductor wafers118have been loaded onto wafer frames116and the wafer frames116have been loaded into the wafer frame cassette114, the wafer frame cassette114is picked up by the transfer system112. The transfer system112transports the wafer frame cassette114for sorting and stocking.

In one example, the transfer system112includes an overhead hoist transport system. The overhead hoist transport system typically includes a cassette carrier mounted on overhead rails. The overhead rails can be coupled to or suspended from the ceiling of various processing rooms. The overhead hoist transport system can also be used to transport semiconductor wafers118during or between various semiconductor processing steps. The transfer system112can include a transfer system other than an overhead hoist transport system without departing from the scope of the present disclosure.

The transfer system112carries the wafer frame cassette114to the transfer port108. The transfer port receives the wafer frame cassette114from the transfer system112. The transfer port108can securely hold the wafer frame cassette114so that individual wafer frames can be sorted and stocked, as will be described in more detail below.

The transfer system112can drop off the wafer frame cassette114at the transfer port108. In this case, the wafer frame cassette114is completely detached from the transfer system112and held that the transfer port108. Alternatively, the transfer system112can bring the wafer frame cassette114to the transfer port108and can hold the wafer frame cassette114at the transfer port108during unloading of the wafer frames116from the wafer frame cassette114.

The wafer frame sorting and stocking system100includes a plurality of storage towers104. Each storage tower includes a plurality of storage slots120. Each storage slot120is configured to hold a wafer frame116. Each storage tower104can include a large number of storage slots120. In one example, each storage tower includes between 150 and 300 storage slots120. The storage towers104can include other numbers of storage slots without departing from the scope of the present disclosure.

The wafer frame sorting and stocking system100includes a robot arm102. The robot arm102is configured to automatically remove individual wafer frames116from the wafer frame cassette114at the transfer port108. The robot arm102transfers each wafer frame116to a selected storage slot120within one of the storage towers104.

The robot arm102can also remove wafer frames116from storage slots120in the storage towers104. The robot arm102can transfer the wafer frames116from the storage slots120to a wafer frame cassette114at the transfer port108. The robot arm102retrieves wafer frames from storage slots120and loads them into the wafer frame cassette114in a precise and careful manner. In practice, when the robot arm loads wafer frames116onto a wafer frame cassette114, it may be the same wafer frame cassette114(first wafer frame cassette) from which the wafer frames116were unloaded or it may be a different wafer frame cassette114(second wafer frame cassette).

In one embodiment, the control system106includes a semiconductor process control system and a storage control system. The semiconductor process control system controls overall processing of semiconductor wafers. Accordingly, the semiconductor process control system can control the transport of semiconductor wafers118, wafer frames116, and wafer frame cassettes114within the semiconductor processing system100. The semiconductor process control system controls the transfer system112. The semiconductor process control system also controls the storage control system.

As described herein, the storage control system performs various functions related to the receiving, storing, sorting, and scanning of wafer frames. The storage control system can perform these functions under control of the semiconductor process control system. Accordingly, actions performed by the storage control system can be performed based on commands received from the semiconductor process control system. Actions performed by the semiconductor process control system and the storage control system are described herein as being performed by the control system106.

The control system106controls the operation of the robot arm102. The control system106controls the robot arm102to remove wafer frames116from a wafer frame cassette114at the transfer port108. The control system106selects a storage slot120for each wafer frame116. The robot arm102stores each wafer frame116in the respective storage slot120specified by the control system106.

The control system106records the identity of each wafer frame116in a wafer frame cassette114that arrives at the transfer port108. After the control system106has recorded the identity of each wafer frame116, the control system106selects storage locations for each of the wafer frames116. Each storage location is a respective storage slot120within one of the storage towers104. The control system106can record storage address data indicating the storage location, i.e. the storage slot120and storage tower104, of each wafer frame116.

The control system106can include one or more processors and one or more computer memories. The computer memories can store data related to the wafer frames116, including wafer frame identities and storage locations. The computer memories can also store data indicating the identity of semiconductor wafers118carried by the wafer frames116. The computer memories can store software instructions that can be executed by the one or more processors. The software instructions can correspond to the various functions of the control system106. Execution of the software instructions can enable the control system106to control the robot arm102.

Components of the control system106can be located in disparate locations. For example, some processing and memory resources of the control system106can be located within the robot arm102, while other processing and memory resources of the control system106can be located external to the robot arm102.

The control system106can also include communication resources. The communication resources can include communication channels and communication devices. The communication resources can include wireless transmitters and receivers for communicating with the robot arm102and other systems and components. The communication resources can include wired communication links that enable communication with the robot arm102and with other systems and components. Many types of communication resources and schemes can be utilized without departing from the scope of the present disclosure.

The control system106can record data indicating a most recent processing step performed on the semiconductor wafers carried by the wafer frames116. The control system106can record data indicating a next processing step or a next destination for the semiconductor wafers118and the wafer frames116that carry them.

In one example, semiconductor wafers118may be loaded onto wafer frames116in preparation for a dicing operation of the semiconductor wafers118. The wafer frames116carrying the semiconductor wafers118may be delivered to the transfer port108. The control system106can record the identities of the wafer frames116and their associated semiconductor wafers118. The control system106can store data indicating that the semiconductor wafers118carried by the wafer frames116have not yet been diced. The control system106can select storage locations for the wafer frames116within the storage towers104. The control system106can then control the robot arm102to transfer the wafer frames116from the wafer frame cassette114to the selected storage locations. The control system106can record the storage locations of the wafer frames116.

In one example, a wafer frame cassette114may arrive at the transfer port108carrying wafer frames116holding semiconductor wafers118that have been diced. The control system106can record the identities of the wafer frames116and their associated semiconductor wafers118. The control system106can store data indicating that the semiconductor wafers118carried by the wafer frames116have been diced. The control system106can select storage locations for the wafer frames116within the storage towers104. The control system106can then control the robot arm102to transfer the wafer frames116from the wafer frame cassette114to the selected storage locations. The control system106can record the storage locations of the wafer frames116.

In one example, the control system106can receive communication indicating that certain currently stored wafer frames116are scheduled to be transported to a dicing station so that their semiconductor wafers118can be diced. The control system106retrieves from memory the storage address data indicating the storage locations of each of the identified wafer frames116. The control system106controls the robot arm102to retrieve the identified wafer frames116from the storage slots120indicated by the storage address data. The robot arm102loads the identified wafer frames116into a wafer frame cassette114at the transfer port108.

In one example, the control system106can receive communication indicating that certain currently stored wafer frames116carrying previously diced semiconductor wafers118are scheduled to be transported for shipping or packaging. The control system106retrieves from memory the storage address data indicating storage locations of each of the identified wafer frames116. The control system106controls the robot arm102to retrieve the identified wafer frames116from the storage slots120indicated by the storage address data. The robot arm102loads the identified wafer frames116into a wafer frame cassette114at the transfer port108.

Though not shown inFIG. 1, the sorting and stocking system100can include a manual port. Wafer frame cassettes114are brought to the manual port manually by technicians, engineers, or scientists. The control system106controls the robot arm102to unload and store the wafer frames from the wafer frame cassette114as described previously. Likewise, the control system106can control the robot arm102to transfer wafer frames from the storage slots120to a wafer frame cassette114at the manual port.

The sorting and stocking system100can include multiple transfer ports108. A first transfer port108may be dedicated for receiving wafer frames116for storage in the storage towers104. A second transfer port108may be dedicated for exporting wafer frames from the storage towers104for transfer to another location or processing station. Various numbers and configurations of transfer ports108and manual transfer ports can be implemented in the wafer frame sorting and stocking system100without departing from the scope of the present disclosure.

The wafer frame sorting and stocking system100can include a barcode scanner110. In this case, each wafer frame116includes a barcode identifying the wafer frame116. The barcode can also identify the semiconductor wafer118carried on the wafer frame116. The barcode scanner110is controlled by the control system106. The barcode scanner110scans the barcodes of the wafer frames116when they arrive at the transfer port108. In this way, the control system106ascertains the identity of each wafer frame116and semiconductor wafer118that arrives at the transfer port108. Additionally, the barcode scanner110can scan the barcodes of all wafer frames116removed from the storage towers104for transfer.

The wafer frame sorting and stocking system100can include systems other than a barcode scanner110for ascertaining the identity of wafer frames116that arrive at the transfer port108. For example, the wafer frame sorting and stocking system100can include imaging systems that capture images of the wafer frames decipher an identification mark included on the wafer frames. Alternatively, the wafer frame sorting and stocking system100can utilize RFID technology or another similar technology to ascertain the identity of wafer frames116that arrive at the transfer port108. In this case, the wafer frames116may carry RFID tags or other similar technology for wirelessly transmitting identification codes related to the wafer frames116. The frame sorting and stocking system100can include many types of identification systems for ascertaining the identities of wafer frames116, wafer frame cassettes114, and semiconductor wafers118without departing from the scope of the present disclosure.

In one embodiment, the control system106implements one or more algorithms for determining where wafer frames are stored among the storage slots120of the storage towers104. The control system106directs the robot arm102to store the various wafer frames116among the storage slots120of the storage towers104in accordance with the one or more algorithms.

In one embodiment, when a wafer frame cassette114is received at the transfer port108, the control system106reads from memory the currently unoccupied storage slots120. Unoccupied storage slots120are available for receiving wafer frames116. The control system106then selects empty and available storage slots120for the wafer frames116of the newly received wafer frame cassette114.

In one embodiment, the control system106may select storage slots120within the one or more of the storage towers104based on a processing stage of the semiconductor wafers118held by the wafer frames116. For example, a storage tower, or a group of storage slots120may be dedicated for storing wafer frames116whose semiconductor wafers118have not yet been diced. Another storage tower104, or group of storage slots120, may be dedicated for storing wafer frames116whose semiconductor wafers118have already been diced. Accordingly, after the barcode scanner110scans the wafer frames116and determines a current processing stage of the wafer frames116based on the barcode data, the control system106may select the designated storage tower104or group of storage slots120for storing the wafer frames116. The control system106can then control the robot arm102to store the wafer frames116accordingly.

In one embodiment, the control system106gives priority to storage slots120that are not adjacent to storage slots120that currently hold a wafer frame116. Accordingly, when available, the control system106controls the robot arm102to store the wafer frames116from the wafer frame cassette114in storage slots120that are not adjacent to an occupied storage slot120. When the storage slots120of the storage towers104are filled with a large number of storage slots120. If such storage slots120are not available, then the control system106controls the robot arm102to store the wafer frames116in storage slots120that are adjacent to occupied storage slots120.

In one embodiment, the control system106receives humidity data from the humidity sensors associated with the various storage towers104. The control system106may select storage slots120for the wafer frames116based on the humidity at those storage slots120. If a humidity controller is not properly operating for one of the storage towers104, then the control system106will not select the storage slots120of that storage tower for receiving wafer frames116. Instead, the control system106will select storage slots120for which the humidity is in a selected humidity range.

In one embodiment, the control system106gives preference to available storage slots120that are closer to the transfer port108. This is because the robot arm is less likely to make an error in transferring wafer frames116, if the robot arm102transfers the wafer frames116over a smaller distance. Accordingly, the control system106selects available storage slots that are closest to the transfer port108.

In one embodiment, the control system106gives preference to available storage slots120that are closest to a height of the transfer port108. This is done because the robot arm102is less likely to make an error if the robot arm102does not need to raise or lower wafer frames116a large distance relative to the transfer port108. This can reduce errors made by the robot arm102in transferring wafer frames116. When the robot arm102retrieves a wafer frame116from the wafer frame cassette114at the transfer port108, the control system106preferably selects a storage slot120that is near a same height as the transfer port108. Accordingly, the control system106selects storage slots120that are closest in height within the storage towers104to the transfer port108.

FIG. 2is a top view of a wafer frame sorting and stocking system100, according to an embodiment. The wafer frame sorting and stocking system100ofFIG. 2illustrates a plurality of storage towers104, two loading ports108, and the robot arm102. The robot arm102, under control of the control system106, can automatically transfer wafer frames116from a transfer port108to transfer slots120within the storage towers104. The robot arm102can also transfer wafer frames from the storage towers104to one of the transfer ports108, as described in relation toFIG. 1.

The wafer frame sorting and stocking system100ofFIG. 2includes ten storage towers104. The storage towers104are arranged in two rows of five storage towers. The robot arm102is positioned between the two rows of storage towers104. The robot arm102is able to access every storage slot120within all of the storage towers104.

The wafer frame sorting and stocking system100ofFIG. 2includes two transfer ports108. A first transfer port108can be utilized for receiving or importing wafer frames116for storage within the storage towers104. A second transfer port108can be utilized for exporting wafer frames116from the storage towers104. Other configurations of transfer ports108can be utilized without departing from the scope of the present disclosure.

FIG. 3is an illustration of a storage tower104, in accordance with one embodiment. The storage tower104includes a plurality of storage slots120. Each storage slot120is configured to receive and store a wafer frame116. Accordingly, each storage slot120has dimensions sufficient to store a wafer frame116. In an example in which a wafer frame116has a diameter between 350 mm and 400 mm, each storage slot120can have first and second lateral dimensions between 420 mm and 450 mm. Each storage slot120can have a vertical dimension or height between 10 and 20 mm. Each storage slot120can include a receiving member for holding a wafer frame116. The storage slots120can include dimensions and configurations other than those described above without departing from the scope of the present disclosure.

The storage tower104can have a height between 5000 mm and 8000 mm. The storage tower104can include 200 and 400 storage slots120. The storage tower104can have other dimensions and other numbers of storage slots120without departing from the scope of the present disclosure.

The storage tower104can include a humidity control system (not shown). The humidity control system can include a humidity sensor and a gas outlet. The humidity sensors can sense a humidity level of the air. The humidity control system can output a dry gas, such as N2gas to adjust or control the humidity responsive to the humidity sensor. In one example, the interior of the storage tower104is maintained at 30% humidity. Alternatively, there may be a single humidity control system for all storage towers104. In this case, each individual storage tower would not have a humidity control system, but rather a single humidity control system can control the humidity of all storage towers104. The various types of humidity systems other than those described above can be implemented to control the humidity within the storage towers104without departing from the scope of the present disclosure.

The storage tower104can include one or more doors or shutters for selectively enabling access to the storage slots120. In one example, a single door can be controllably opened and closed by the control system102to enable the robot arm102to gain access to the storage slots120. In one example, the storage tower104can include multiple doors that can be controllably opened and closed to each provide access to a group of storage slots120. In one example, the storage tower104includes a respective door for each slot120to selectively enable access to individual storage slots120. Other types of access configurations for the storage slots120can be utilized without departing from the scope of the present disclosure.

FIG. 4is a perspective view of the wafer frame sorting and stocking system100ofFIG. 2, according to an embodiment. The wafer frame sorting and stocking system100includes a manual transfer port130not visible in the view ofFIG. 2. The robot arm102is not visible in the view ofFIG. 4.

Wafer frame cassettes114are brought to the manual transfer port130manually by technicians or other personnel. The control system106controls the robot arm102to unload and store the wafer frames116from the wafer frame cassette114as described previously. Likewise, the control system106can control the robot arm102to transfer wafer frames from the storage slots120to a wafer frame cassette114at the manual transfer port130.

FIG. 5is a side view of the wafer frame sorting and stocking system100ofFIG. 2, according to an embodiment. One row of storage towers104, the transfer ports108, and the manual transfer port130are visible inFIG. 5. The robot arm102is not visible in the view ofFIG. 5.

FIG. 6is an illustration of a wafer frame cassette114, according to an embodiment. The wafer frame cassette includes a handle132. The handle132enables an automated transfer system to carry and transport the wafer frame cassette114to and from the transfer port108. The handle132can also enable a human to carry the wafer frame cassette114to and from the manual transfer port130.

The wafer frame cassette114includes a plurality of wafer frame slots134. Each wafer frame slot134is configured to carry a wafer frame116. In one example, the wafer frame cassette114includes between 10 and 15 wafer frame slots134. The wafer frame cassette114can include other numbers of wafer frame slots134without departing from the scope of the present disclosure.

FIG. 7is an illustration of a wafer frame116, according to an embodiment. The wafer frame116is carrying a semiconductor wafer118. The wafer frame116includes a ring135. The ring135has an interior diameter that is larger than the diameter of the semiconductor wafer118. For example, if the semiconductor wafer118is a 300 mm wafer, then the wafer frame116may have an interior diameter between 350 mm and 400 mm.

The wafer frame116includes an adhesive membrane136stretched across the interior of the ring135. The adhesive membrane136can include a tape or another material stretched across the interior of the ring. The semiconductor wafer118is placed on the adhesive membrane. The wafer frame116can carry a semiconductor wafer118other than a 300 mm wafer without departing from the scope of the present disclosure. Additionally, the wafer frame116can have dimensions, membranes and configurations other than those described above without departing from the scope of the present disclosure.

FIG. 8is an illustration of a robot arm102, according to an embodiment. The robot arm102can be utilized in the wafer frame sorting and stocking system100described herein. In particular, the robot arm102can be utilized to transfer wafer frames116between storage slots120and transfer ports108under the control of the control system106.

The robot arm102includes a base140. The base140is positioned on the ground or on a selected platform. The robot arm102includes telescoping members142. The telescoping members142telescope vertically to enable retrieval or storage of wafer frames116at the varying heights of the storage slots120in the various storage towers104.

A mount144is coupled to the telescoping members142. An arm member146is mounted to the mount144. The arm member146can rotate relative to the mount144. An arm member147is coupled to the arm member146. The arm member147can rotate relative to the arm146. In arm member148is coupled to the arm member147. The arm number148can rotate relative to the arm member147. Carrying prongs150are attached to the end of the arm member148. The carrying prongs150pickup and carry the wafer frames116. The various arm members and their rotatability enables the robot arm102to reach all storage slots120within the various storage towers104. A robot arm102can include configurations other than that shown inFIG. 8without departing from the scope of the present disclosure.

The robot arm102can include internal electronic circuitry. The internal electronic circuitry causes the movements of the various components of the robot arm102. The internal electronic circuitry can include processors, computer memories, and communication resources. A portion of the control system106can be included in the electronic circuitry of the robot arm102.

FIG. 9is a flow diagram of a method900, according to an embodiment. At902, the method900includes receiving, at a first transfer port, a wafer frame cassette including a plurality of wafer frames. One example of a first transfer port is the transfer port108ofFIG. 1. One example of a control system is the control system106ofFIG. 1. One example of a wafer frame cassette is the wafer frame cassette114ofFIG. 1. At904the method900includes recording, with a control system, an identity of each wafer frame. One example of a control system is the control system106ofFIG. 1. At906, the method900includes selecting, with the control system, a respective storage location for each wafer frame within an array of storage towers. One example of storage towers is the storage towers104ofFIG. 1. At908, the method900includes transferring, with a robot arm under control of the control system, each wafer frame to the respective storage location. One example of a robot arm is the robot arm102ofFIG. 1. At910, the method900includes recording, with the control system for each wafer frame, the storage location.

FIG. 10is a flow diagram of a method1000, according to an embodiment. At1002, the method1000includes receiving, at a first transfer port, a wafer frame cassette including a plurality of wafer frames. One example of a first transfer port is the transfer port108ofFIG. 1. One example of a wafer frame cassette is the wafer frame cassette114ofFIG. 1. One example of a wafer frame is the wafer frame116ofFIG. 1. At1004, the method1000includes transferring, with a robot arm, each wafer frame from the wafer frame cassette into a respective storage slot in one of a plurality of storage towers. One example of a robot arm is the robot arm102ofFIG. 1. One example of storage towers is the storage towers104ofFIG. 1. One example of a storage slot is the storage slots120ofFIG. 1. At1006, the method1000includes controlling the robot arm with a control system. One example of a control system is the control system106ofFIG. 1. At1008, the method1000includes recording, with the control system, a storage location of each wafer frame.

FIG. 11is a flow diagram of a method1100, according to one embodiment. At1102, the method1100includes transporting, with an overhead hoist transport system, a wafer frame cassette into a wafer frame storage transfer port based on the command from a semiconductor process control system. One example of an overhead hoist transport system is the transfer system112ofFIG. 1. One example of a wafer frame cassette is the wafer frame cassette114ofFIG. 1. One example of a wafer frame storage transfer port is the transfer port108ofFIG. 1. One example of a semiconductor process control system is the control system106ofFIG. 1. At1104, the method1100includes transferring, with a robot arm, wafer frames from the wafer frame cassette at the transfer port to storage slots of one or more storage towers. One example of a robot arm is the robot arm102ofFIG. 1. One example of wafer frames is the wafer frames116ofFIG. 1. One example of a storage tower is the storage towers104ofFIG. 1. One example of storage slots is the storage slots120ofFIG. 1. At1106, the method1100includes scanning a bar code of each wafer frame. At1108, the method1100includes sending barcode data and storage location data for each wafer frame to the semiconductor process control system. At1110, the method1100includes transporting, with the overhead hoist transport system, the empty wafer frame cassettes from the transfer port.

FIG. 12is a flow diagram of a method1200, according to one embodiment. At1202, the method1200includes transporting, with an overhead hoist transport system, an empty wafer frame cassette to a wafer frame storage transfer port based on the command from the semiconductor process control system. One example of an overhead hoist transport system is the transfer system112ofFIG. 1. One example of a wafer frame cassette is the wafer frame cassette114ofFIG. 1. One example of a wafer frame storage transfer port is the transfer port108ofFIG. 1. One example of a semiconductor process control system is the control system106ofFIG. 1. At1204, the method1200includes transferring, with the robot arm, wafer frames from storage slots of one or more storage towers to the wafer frame cassette. One example of a robot arm is the robot arm102ofFIG. 1. One example of wafer frames is the wafer frames116ofFIG. 1. One example of a storage tower is the storage towers104ofFIG. 1. One example of storage slots is the storage slots120ofFIG. 1. At1206, the method1200includes scanning a bar code of each wafer frame. At1208, the method1200includes transporting, with the overhead hoist transport system, the loaded wafer frame cassette from the transfer port.

FIG. 13is a flow diagram of a method1300, according to one embodiment. At1302, the method1300includes transporting, with an overhead hoist transport system, the first wafer frame cassette to a first transfer port based on a command from the semiconductor process control system. One example of an overhead hoist transport system is the transfer system112ofFIG. 1. One example of a wafer frame cassette is the wafer frame cassette114ofFIG. 1. One example of a wafer frame storage transfer port is the transfer port108ofFIG. 1. One example of a semiconductor process control system is the control system106ofFIG. 1. At1304, the method1300includes transporting, with the overhead hoist transport system, a second wafer frame cassette to a second transfer port based on the command from the semiconductor process control system. At1306, the method1300includes transferring, with a robot arm, wafer frames from the first wafer frame cassette to the second wafer frame cassette. At1308, the method1300includes scanning a bar code of each wafer frame. At1310, the method1300includes transporting, with the overhead hoist transport system, the first wafer frame cassette from the first transfer point. At1312, the method1300includes transporting, with the overhead hoist transport system, the second wafer frame cassette the second transfer port.

In one embodiment, a system includes a first transfer port configured to receive a first wafer frame cassette from a transfer system. The system includes a plurality of storage towers each including a plurality of storage slots. The system includes a robot arm configured to retrieve wafer frames from the first wafer frame cassette at the transfer port and to store each wafer frame in a respective storage slot. The system includes a control system configured to record an identity of each wafer frame received at the first transfer port, to control the robot arm, and to record, for each wafer frame, storage address data identifying the storage slot of the wafer frame.

In one embodiment, a method includes receiving, at a first transfer port a wafer frame cassette including a plurality of wafer frames. The method includes transferring, with a robot arm, each wafer frame from the wafer frame cassette into a respective storage slot in one of a plurality of storage towers. The method includes controlling the robot arm with a control system. The method includes recording, with the control system, a storage location of each wafer frame.

In one embodiment, a method includes receiving, at a first transfer port, a wafer frame cassette including a plurality of wafer frames. The method includes recording, with a control system, an identity of each wafer frame. The method includes selecting, with the control system, a respective storage location for each wafer frame within an array of storage towers. The method includes transferring, with a robot arm under control of the control system, each wafer frame to the respective storage location. The method includes recording, with the control system for each wafer frame, the storage location.

The various embodiments described above can be combined to provide further embodiments. All U.S. patent application publications and U.S. patent applications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary, to employ concepts of the various patents, applications and publications to provide yet further embodiments.