# US 2021/0242057 A1 · Automated material handling systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242057 A1 - Document ID: US20210242057A1 - Status: Published application - Kind: A1 - Application number: 17/126,872 - Filed: 2020-12-18 - Published: 2021-08-05 - Earliest claimed: 2020-01-30 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Applicants: Taiwan Semiconductor Manufacturing Co., Ltd. - Inventors: Yen Le LEE; Yen-Yu CHEN; Wei Chih CHEN; Tai Hsiang LIAO; Kai-Ping JHAN - Web page: https://patentgrep.com/patent/US20210242057A1 ## CPC - H10P 72/3221: {Overhead conveying} - H10P 72/0616: {Monitoring of warpages, curvatures, damages, defects or the like} - H10P 72/3202: {Mechanical details, e.g. rollers or belts} - H10P 72/3222: {Loading to or unloading from a conveyor} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract An overhead transport vehicle is described for association with an Automated Material Handling System (AMHS). The overhead transport vehicle provides features to the AMHS by which the AMHS is able to reduce a number of manual urgent lot rescues by the fab operator when a logistic algorithm controlling traffic in the AMHS is unable to transport the front opening unified pods (FOUP) from one tool to the subsequent tool in the sequence of the process steps within the q-time due to unexpected problems. An indicator on the overhead transport vehicle which helps the fab operator with spotting a lot in trouble is described. A backup power source on the overhead transport vehicle used in case of a main power failure is also described. ## Claims ### Claim 1 An overhead transport vehicle comprising: a power control circuit, which, in operation, determines a source of power for the overhead transport vehicle; and a backup power source for the overhead transport vehicle, wherein the power control circuit, in operation, switches the source of power from a main power source for the overhead transport vehicle to the backup power source. ### Claim 2 (depends on 1) The overhead transport vehicle according to claim 1, wherein the power control circuit, in operation, switches the source of power from the main power source to the backup power source when the main power source supplies insufficient power to the overhead transport vehicle. ### Claim 3 (depends on 1) The overhead transport vehicle according to claim 1, wherein the power control circuit, in operation, monitors the power supplied from the main power source when the overhead transport vehicle is powered by the backup power source. ### Claim 4 (depends on 3) The overhead transport vehicle according to claim 3, wherein the power control circuit, in operation, switches the source of power from the backup power source to the main power source when the power control circuit measures sufficient power from the main power source. ### Claim 5 (depends on 1) The overhead transport vehicle according to claim 1, wherein the main power source, in operation, supplies power through a power rail. ### Claim 6 (depends on 1) The overhead transport vehicle according to claim 1, further comprising an indicator, which, in operation, indicates a status of the backup power source. ### Claim 7 (depends on 1) The overhead transport vehicle according to claim 1, further comprising a plug-in connector for the backup power source. ### Claim 8 (depends on 1) The overhead transport vehicle according to claim 1, wherein the backup power source includes a main battery and at least one backup battery. ### Claim 9 An overhead transport vehicle comprising: a communication circuit, which, in operation, receives a sequence of process steps for a lot from a controller in an Automated Material Handling System (AMHS), the sequence of process steps including a time constraint information for intervals between two or more process steps in the sequence of process steps; a memory, which, in operation, stores the sequence of process steps for the lot; a priority indicator disposed on an exterior of the overhead transport vehicle; and a processing circuit, which, in operation, outputs an indication on the priority indicator based a level of urgency for the lot. ### Claim 10 (depends on 9) The overhead transport vehicle according to claim 9, wherein the indication on the priority indicator is determined based on a level of urgency. ### Claim 11 (depends on 10) The overhead transport vehicle according to claim 10, wherein the level of urgency is determined by the processing circuit based on at least one of conditions, the conditions including the time constraint information, a lot type for the lot, history data from a similar sequence of process steps, or a production deadline assigned for the lot. ### Claim 12 (depends on 11) The overhead transport vehicle according to claim 11, wherein the lot type includes a reworkable lot and a non-reworkable lot. ### Claim 13 (depends on 11) The overhead transport vehicle according to claim 11, wherein the controller assigns different weights for each of the conditions used to determine the level of urgency. ### Claim 14 (depends on 9) The overhead transport vehicle according to claim 9, wherein the time constraint information limits an interval time between two or more process steps in the sequence of process steps. ### Claim 15 (depends on 9) The overhead transport vehicle according to claim 9, further comprising a backup battery supplying power to the priority indicator when a main source of power to the overhead transport vehicle is not available. ### Claim 16 A method of transporting an urgent lot, comprising: determining an urgent level for a lot; displaying an urgent level status based on the determined urgent level for the lot; transmitting a rescue signal to an automated material handling system (AMHS) based on the determined urgent level for the lot; and determining a shortest route to a destination for the lot. ### Claim 17 (depends on 16) The method according to claim 16, further comprising transmitting a ban signal to clear the shortest route to the destination. ### Claim 18 (depends on 16) The method according to claim 16, wherein the urgent level is determined by a processing circuit based on at least one of conditions, the conditions including q-time remaining for the lot, a lot type for the lot, history data from a similar sequence of process steps, or a production deadline assigned for the lot. ### Claim 19 (depends on 16) The method according to claim 16, wherein the determined urgent level is displayed on a priority indicator disposed on an exterior of an overhead transport vehicle. ### Claim 20 (depends on 16) The method according to claim 16, wherein the destination is a nearest available entrepot from an original destination.