Foundry implementation of advanced automated decision-making
08/01/2006
AMD has shown in its own fabs that very tight and automated control is essential to manufacture leading-edge products. Recently, automated precision manufacturing (APM) was implemented in Chartered’s Fab 7, a foundry for AMD products. As a result, AMD and Fab 7 have achieved the desired improved control and reliable construction of high-performance transistors required for AMD’s products.
To succeed in today’s highly competitive markets, global electronics companies need suppliers and partners that can deliver the right solutions, on time, on budget, and in the appropriate quantities. These manufacturing and fulfillment issues can be vitally important to a company’s bottom line. AMD has invested heavily over the past decade in upgrading its manufacturing technologies and employee skills to achieve maximum efficiency and dependability in its production infrastructure. These investments include millions of dollars for framework and application development and testing, for building the teams required to accomplish the goals, and for the infrastructure to run AMD’s factories.
Implementation of APM
AMD defines mature yield as the yield at which a technology becomes economically viable to produce in high volume. In the last three years alone, AMD has managed to reduce the time to mature yield by up to 80% through the use of three distinct technologies (Fig. 1). The level of mature yield for each technology is equal to or greater than those of previous technologies. The significance of accomplishing such rapid yield learning is amplified when each technology is more complex, more demanding, and more difficult to produce than the previous technology. The expectation as AMD begins manufacturing 300mm wafers is to be able to introduce technologies at or near mature yields. APM is critical to the realization of that expectation.
 Figure 1. AMD wafer yield vs. production volume for three technology nodes. |
Manufacturing efficiency of this magnitude makes APM an extremely valuable technology both internally and externally to AMD. As a result, portions of APM are being transferred to Chartered Semiconductor’s Fab 7 in Singapore. To support Fab 7’s work as a foundry for AMD64 products, AMD and Chartered are using select APM technologies to ensure that the fab can operate with the necessary speed, accuracy, and agility.
Several key steps were associated with the successful implementation of APM technology in Fab 7 that are common to all other APM scenarios. The first was establishing that the APM mindset was essential to the creation of a foundation from which APM solutions could be built. Focused training occurred repeatedly with an emphasis on the substantial positive impact that APM can have on Fab 7’s bottom line operations. This initial step included workshops over several months with AMD and Chartered managers and engineers that resulted in a better understanding of each other’s operations.
Next, a plan for integration was developed that encompassed all the relevant factory systems. The Fab 7 CIM team linked APM systems into the manufacturing framework and established communication of the data that is the lifeblood of APM. In addition, Chartered established a central control engineering team responsible for receiving APM control technology and translating it into custom solutions to fit Fab 7’s distinct control needs. Fab 7 replicated AMD’s model of building a central, dedicated, control engineering staff similar in size and composition to those used in AMD fabs. Thousands of man-hours were required to develop the organization and implement the infrastructure and initial applications.
Foundry environment challenges
The foundry environment presented unique manufacturing and control challenges. The large number of products as well as the simultaneous high, medium, and low volume of each product required more sophisticated systems and control solutions than a dedicated fab with one or few products at constant volumes. Initial requirements indicated that high-volume/high-product mix solutions would be necessary to make an impact on Chartered’s Fab 7. Differences in the factory systems also necessitated changes to the control system infrastructure for integration into the manufacturing execution system (MES) used in Fab 7. The modular nature of AMD’s APM framework mitigated many issues normally associated with changing the infrastructure.
 Figure 2. Timeline of APM implementation at Chartered Semiconductor’s Fab 7. |
The close collaboration shown by the teams from AMD and Chartered resulted in an APM implementation that occurred in record time. Figure 2 shows a timeline of events chronicling the implementation of the photolithography run-to-run controllers to overlay and exposure critical dimension (CD). The photolithography control applications were released for initial production after only five months of APM framework integration, controller modification, and training. The run-to-run applications were implemented on all remaining process layers within another two months.
Overlay error and exposure CD results
Figures 3 and 4 show the effect of AMD’s APM on the Fab 7 environment as it was propagated. In Fig. 3, the overlay error before and after AMD’s overlay controller was implemented is compared. After implementation of the controller, overlay error is effectively controlled for high- and low-running products.
The improvements in root mean squared error (RMSE) for the overlay and exposure CD run-to-run controllers employed in Fab 7 are shown in Fig. 4. The percentage of controller distribution across the photolithography layers are also shown in Fig. 4 as the controllers were deployed across all the targeted process operations with the corresponding RMSE reductions.
 Figure 4. Effects over time in Chartered’s Fab 7: a) exposure run-to-run control and b) overlay run-to-run control. |
The overlay and exposure CD run-to-run controllers enabled world-class control capability and provided the flexibility to mix and match the current products to the process tools available for manufacturing. This flexibility eliminated the need to dedicate tools to particular products. Significant operational gains were achieved by reducing the number of reworks. All of these benefits greatly increased the effective capacity of the fab, reduced process variation due to tool differences, reduced operational cost, and increased fab efficiency [1].
Conclusion
AMD and Chartered created and trained an APM organization, integrated an APM Framework, and implemented controllers at multiple layers across the majority of products in approximately nine months. This effort resulted in vast improvements across the fab, but especially in the photolithography module, culminating with nearly a 6× reduction in exposure error. The speed at which APM was integrated into Fab 7’s manufacturing environment and fully assimilated into the operations underscores the flexible design of AMD’s APM Framework and solutions.
Reference
1. P.P. Lau et al., “Implementation of Photolithography RtR Control in a 300mm Foundry,” AEC/APC Europe, p. 301, March 2006.
Richard J. Markle received his masters in inorganic chemistry from the U. of Texas at Austin and is the senior program manager of the automated precision manufacturing technology integration strategic programs group at Advanced Micro Devices.
Matthew Ryskoski received his BS in chemical engineering from Texas A&M U. and is a senior process development engineer within the automated precision manufacturing technology integration strategic programs group at Advanced Micro Devices, 5204 East Ben White Blvd., M/S 563, Austin, TX 78741; ph 512/602-1084; e-mail [email protected].