Lot process order modification to improve detection of manufacturing effects

• US 8,676,367 B2
• Filed: 10/28/2010
• Issued: 03/18/2014
• Est. Priority Date: 10/28/2010
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Yamartino, John M.
• Primary Examiner(s): Padmanabhan, Kavita
• Assistant Examiner(s): DUNN, DARRIN D
• Application Number:
  US12/914,223
• Publication Number:
  US 20120109351A1
• Time in Patent Office: 1,237 Days
• Field of Search: 700/99, 700/100, 700/101, 700/102, 700/103, 700/104, 700/108, 700/109
• US Class Current: 700/101
• CPC Class Codes: H01L 21/67276 Production flow monitoring, e.g. for increasing throughput program-control systems per se G05B19/00, e.g. total factory control G05B19/418
• CPC Class Codes: H01L 21/67745 characterized by movements or sequence of movements of transfer devices

Abstract

A system for lot based, multi-step wafer manufacturing processes is provided and includes a transfer apparatus, disposed among tools for performing respective process steps on each wafer of each lot of wafers transferred thereto, the transfer apparatus being configured to transfer each lot from a current tool to a next tool in accordance with a process step sequence, a dispatcher operably coupled to the transfer apparatus to modify the lot order in response to a modification condition detection, a measurement unit configured to receive each wafer of each fully processed lot and to collect measurements therefrom and a processor disposed in signal communication with the dispatcher and the measurement unit to analyze the measurements relative to the lot order for evidence that a process step of a corresponding tool is responsible for performance effects.

Claims

1. A system for lot based, multi-step wafer manufacturing processes, the system comprising:

a transfer apparatus, disposed among tools for performing respective process steps on each wafer of each lot of wafers transferred thereto, the transfer apparatus being configured to transfer each lot from a current tool to a next tool in accordance with a process step sequence;

a plurality of detectors disposed at each of the tools to monitor current conditions and to issue signals indicative of the monitoring;

a dispatcher operably coupled to the transfer apparatus to modify the lot order at a tool in response to a modification condition detection at the tool, the modification condition being recognized by the dispatcher in accordance with the signals issued by the detectors;

a measurement unit configured to receive each wafer of each fully processed lot and to collect measurements therefrom; and

a processor disposed in signal communication with the dispatcher and the measurement unit to analyze the measurements relative to the modified lot order for evidence that a process step associated with the tool at which the modification of the lot order was executed is responsible for performance effects;

wherein the dispatcher forces a lot queue of multiple lots and then modifies the lot order, wherein the dispatcher forces the lot queue of multiple lots by;

stopping an execution of a process step at a corresponding tool; and

in a case in which a tool comprises a fast executing sub-tool and a slow executing sub-tool, sending lots to only the slow executing sub-tool having a substantial increase in lot queue length.

2. The system according to claim 1, wherein the tools comprise tools for executing plasma vapor or chemical vapor deposition (PVD or CVD), ion implantation, lithography, etching, stripping, cleaning, annealing, rapid thermal processing (RTP), furnace processing chemical mechanical planarization (CMP) and/or metrology.

3. The system according to claim 1, wherein the modification condition is a queue length of multiple lots such that a lot queue length exceeds a predefined number of lots.

4. The system according to claim 1, wherein the dispatcher modifies the lot order by randomization of an order of lots within a lot queue of a given length.

5. The system according to claim 1, wherein the dispatcher modifies the lot order by reversal of an order of the lots within a lot queue of a given length.

6. A system for lot based, multi-step wafer manufacturing processes, the system comprising:

a transfer apparatus, disposed among tools for performing respective process steps on each wafer of each lot of wafers transferred thereto, the transfer apparatus being configured to transfer each lot from a current tool to a next tool in accordance with a process step sequence;

a plurality of detectors disposed at each of the tools to monitor current conditions and to issue signals indicative of the monitoring;

a dispatcher operably coupled to the transfer apparatus to modify the lot order in response to a lot order constraint and to modify the lot order at a tool in response to a modification condition detection at the tool, the modification condition being recognized by the dispatcher in accordance with the signals issued by the detectors;

a measurement unit configured to receive each wafer of each fully processed lot and to collect measurements therefrom; and

a processor disposed in signal communication with the dispatcher and the measurement unit to analyze the measurements relative to the modified lot order for evidence that a process step associated with the tool at which the modification of the lot order was executed is responsible for performance effects;

wherein the dispatcher forces a lot queue of multiple lots and then modifies the lot order, wherein the dispatcher forces the lot queue of multiple lots by;

stopping an execution of a process step at a corresponding tool; and

in a case in which a tool comprises a fast executing sub-tool and a slow executing sub-tool, sending lots to only the slow executing sub-tool having a substantial increase in lot queue length.

7. The system according to claim 6, wherein the lot order constraint comprises a priority indication.

8. The system according to claim 6, wherein the tools comprise tools for executing plasma vapor or chemical vapor deposition (PVD or CVD), ion implantation, lithography, etching, stripping, cleaning, annealing, rapid thermal processing (RTP), furnace processing chemical mechanical planarization (CMP) and/or metrology.

9. The system according to claim 6, wherein the modification condition is a queue length of multiple lots such that a lot queue length exceeds a predefined number of lots.

10. The system according to claim 6, wherein the dispatcher modifies the lot order by randomization of an order of lots within a lot queue of a given length.

11. The system according to claim 6, wherein the dispatcher modifies the lot order by reversal of an order of the lots within a lot queue of a given length.

12. A method of operating a system for lot based, multi-step wafer manufacturing processes, the method comprising:

monitoring current conditions by detectors at tools for performing the process steps and issuing signals indicative of the monitoring;

at selected process steps and for available lots, determining at the corresponding tools a modified lot order that is different from a lot order in a prior process step in response to a modification condition detection recognized by a dispatcher in accordance with the issued modifying the lot order at each of the selected process steps by the dispatcher in accordance with the modified lot order;

processing the lots according to the modified lot order;

collecting measurements from wafers within the lots that have been fully processed; and

analyzing the measurements relative to lot order sequence data for evidence that one process step from among the selected process steps at which each of the lot order modifications occurred is responsible for performance effects and that the other process steps are not responsible for the performance effects,

wherein the analyzing comprises identifying as the evidence organized data associated with the one of the process steps and disorganized data associated with the other process steps;

wherein the determining comprises forcing a lot queue of multiple lots and then modifying the lot order, wherein the forcing is accomplished by the dispatcher and comprises;

stopping an execution of a process step at a corresponding tool; and

in a case in which a tool comprises a fast executing sub-tool and a slow executing sub-tool, sending lots to only the slow executing sub-tool having a substantial increase in lot queue length.

13. The method according to claim 12, wherein the available lots are identified in accordance with a lot order constraint.

14. The method according to claim 12, wherein the determining comprises randomizing the lot order of an order of lots within a lot queue of a given length.

15. The method according to claim 12, wherein the determining comprises reversing the lot order within a lot queue of a given length.