Patent Application
20050240298
The present invention relates to a fabrication control system and particularly to a fabrication control system capable of controlling fabrication backup applied in multiple fabrication facility locations.
While cross-Fab backup within a fabrication system is clearly desired, it is not routinely practiced due to great difficulty in monitoring and controlling a plurality of separately located independent fabrication facilities. Cross-Fab backup is presently executed manually in the conventional fabrication system, an inefficient and mistake-prone process. Moreover, owing to the complexity of wafer fabrication, the conventional cross-Fab backup cannot address every detail of process operation, resulting in yield loss. In U.S. Patent Application 20020165629 (Backup control system for optimizing utilization of multiple fabrication facilities), Ho et al. disclose a backup control system and method for monitoring and controlling multiple fabrication facilities. The above-mentioned invention relieves the manual burden of conventional cross-Fab backup and enhances the overall utilization of the multiple fabrication facilities.
In wafer fabrication processes, however, most work-in-process (WIP) has manufacturing constraints, based on process time, equipment, Advance Process Control (APC), and contamination. These manufacturing constraints are set to prevent mis-operation and yield loss. Both the conventional method and the cited disclosure fail to relay these manufacturing constraints between Fabs during cross-Fab backup, thereby increasing the likelihood of mis-operation and yield loss, and thus counteracting the benefits of cross-Fab backup operation.
Hence, there is a need for a fabrication system that addresses mis-operation during cross-Fab backup arising from the existing technology.
It is therefore an object of the invention to provide a system and method of backup control to enhance the overall utilization of a fabrication system without yield loss. To achieve this and other objects, the present invention provides a system and method of relaying manufacturing constraints between separately located Fabs during cross-Fab backup.
According to one embodiment of the invention, a backup control system is provided within a fabrication system. The fabrication system contains a plurality of separately located fabrication facilities, each of which contains a computer assisted production control system and a plurality of processing tools.
The backup control system, coupled with the computer assisted production control systems, provides control of backup operations between the fabrication facilities, and relays manufacturing constraints of the backup-operated articles before and after the backup operation.
According to another embodiment of the invention, a backup control method is provided controlling the backup operation of articles in the separately located fabrication facilities within the fabrication system mentioned above. First, a backup request is received from a first fabrication facility, wherein the backup request comprises identification codes of the backup-operated articles, backup operation, and support manufacturing facility. Second, a first manufacturing constraint is retrieved from the first manufacturing facility according to the identification codes of the backup-operated articles and the backup operation. Then the backup request and the first manufacturing constraint are transmitted to a second manufacturing facility according to the identification code of the support manufacturing facility. Next, a backup completion report is received from the second fabrication facility, wherein the backup completion report comprises identification codes for the backup-operated articles and a second manufacturing constraint. Then, the backup completion report is transmitted to the first fabrication facility.
The above-mentioned method may take the form of program code embodied in a computer readable tangible media. When the program code is loaded into and executed by a machine, the machine becomes an apparatus for practicing the invention.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The present invention will now be described with reference to FIGS. 2 to 5, which in general relate to a backup control system within a fabrication system. While the preferred embodiment of the invention operates with semiconductor fabrication systems, it is understood that the type of article processed by the fabrication system is not critical to the present invention, and any fabrication system processing articles having dynamic manufacturing constraints may utilize the present invention.
Each Fab comprises a plurality of processing tools for performing various wafer fabrication functions and a manufacturing execution system (MES) for controlling the processing tools thereof. Fab 21, for example, contains MES 210 and processing tools 21a to 21n, wherein the processing tool 21a has photolithography function. Fab 23 contains MES 230 and processing tools 23a to 23n, wherein the processing tool 23a also has photolithography function.
Backup control system 25, coupled with MES 210 and MES 230 through a network 27, controls backup operations between Fabs 21 and 23, and relays manufacturing constraints of the backup-operated wafer lots before and after the backup operation. When the capacity of processing tool 21a to process wafer lots scheduled to be processed by processing tool 21a is exceeded there is a need for backup operation. As mentioned above, since both processing tools 21a and 23a are capable of photolithography processing, processing tool 23a is a candidate for backup operation on behalf of processing tool 21a. If processing tool 23a has suitable capacity and capability, then processing tool 21a sends a backup request to backup control system 25 requesting backup support from Fab 23. The backup control system 25 receives the backup request, retrieves the corresponding manufacturing constraints, and relays the manufacturing constraints together with the backup request to Fab 23. Fab 23 receives the backup request and the corresponding manufacturing constraints, and waits for the backup-due wafer lot. Processing tool 23a processes the wafer lot when it arrives. When the backup operation is accomplished, Fab 23 updates the manufacturing constraints, returns the processed wafer lot to Fab 21, and sends a backup completion report to backup control system 25. The backup control system 25 receives the backup completion report and the updated manufacturing constraints of the backup-operated articles from Fab 23, and relays them to Fab 21.
First, a backup request is received from Fab 21 (step S31) The content of the backup request is shown in
Second, manufacturing constraints corresponding to the backup-operated wafer lot are retrieved from MES 210 according to the lot ID of the backup-operated wafer lot and the steps scheduled to be executed in Fab 23 (step S33).
After the backup operation is accomplished, a backup completion report and updated manufacturing constraints are received from Fab 23 (step S35) and transmitted to Fab 21 (step S37). When Fab 21 receives the backup completion report and updated manufacturing constraints, it updates the manufacturing constraints of the backup-operated wafer lot accordingly. Then the wafer lot continues processing in Fab 21.
The backup control method implemented in the backup control system of the present invention, or certain aspects or portions thereof, may take the form of program code (i.e. instructions) embodied in a tangible media, such as floppy diskettes, CD-ROMS, hard drives, or any other machine-readable storage medium, wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. The methods and apparatus of the present invention may also be embodied in the form of program code transmitted over some transmission medium, such as electrical wiring or cabling, through fiber optics, or via any other form of transmission, wherein, when the program code is received and loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates analogously to specific logic circuits.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
