Statistical equipment modeling for VLSI manufacturing: an application for LPCVD

Lin, Kevin; Spanos, Costas J.

doi:10.1109/66.61971

Cited by 63 publications

(13 citation statements)

References 19 publications

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“…They are given by with the rates expressed in &min, P in mtorr, T in K, and Q in sccm. The parameters are given [14] to be c1 = 20.65, and Cg, = 1.85 x where we have dropped the units for convenience. d l , and d2 represent the drift terms.…”

Section: Simulation Resultsmentioning

confidence: 99%

Designing response surface model-based run-by-run controllers: a worst case approach

Baras

Patel

1996

IEEE Trans. Comp., Packag., Manufact. Technol. C

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Abstract-This paper presents a framework for carrying out run-by-run (RbR) control via a deterministic worst-case approach. In particular the RbR controller developed tries to minimize the worst-case performance of the plant. This yields a methodology for handling uncertainty. A consequence of using the deterministic approach is that we no longer need any assumptions on the statistics of the noise. Rather, what we require is that the noise be bounded. Thus, we can also deal with nonGaussian and correlated noise. We provide results comparing the performance of the controller to a recursive least squares ( U S ) based controller.Index Terms-Run-by-run control, deterministic approach, bounded noise, worst-case design, ellipsoidal algorithms, response surface models.

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Section: Simulation Resultsmentioning

confidence: 99%

Designing response surface model-based run-by-run controllers: a worst case approach

Baras

Patel

1996

IEEE Trans. Comp., Packag., Manufact. Technol. C

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“…When there are parallel chambers at process step , the successive wafers visit the chambers in a cyclic order during a robot work cycle. For instance, the chamber visit sequence for wafer flow pattern (2,3) is , where is the -th parallel chamber at process step . Such cyclic use of parallel chambers is intended for fair use of the chambers.…”

Section: A Cluster Tool Operation Modelmentioning

confidence: 99%

“…A feasible schedule that satisfies the time window constraints require the sum of the token sojourn times at the places in each parallel path for a synchronizing transition is identical [20]. Therefore, we have (2), found at the bottom of the page. where and .…”

Section: Linear Programming For Schedulability Analysis and Schedumentioning

confidence: 99%

“…A weak uniformity requirement that limits the wafer delay variation for the th process step within tolerance is written as (4) Therefore, a feasible schedule should satisfy constraints (1), (2), and (3) or (4). We wish to find a feasible schedule that minimizes the tool cycle time,…”

Section: Linear Programming For Schedulability Analysis and Schedumentioning

confidence: 99%

“…Otherwise, the wafer is subject to quality problems due to residual gases or heat. For example, low pressure chemical vapor deposition (LPCVD) is processed under medium vacuum of 0.25-20 torr, and higher temperature of 550 C-800 C in order to form nonvolatile solid films like nitride, oxide, Epi-Si and poly-Si [2], [3]. When the wafer delay at each process step of LPCVD exceeds 20 s, the wafer surface deteriorates because of excessive exposure to residual gases under high temperature and the wafer is scrapped.…”

Section: Introductionmentioning

confidence: 99%

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Scheduling analysis of time-constrained dual-armed cluster tools

Kim

Lee

et al. 2003

IEEE Trans. Semicond. Manufact.

245

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Abstract-Cluster tools, each of which consists of several singlewafer processing chambers and a wafer handling robot, have been increasingly used for diverse wafer fabrication processes. Processes such as some low pressure chemical vapor deposition processes require strict timing control. Unless a wafer processed at a chamber for such a process leaves the chamber within a specified time limit, the wafer is subject to quality problems due to residual gases and heat. We address the scheduling problem for such time-constrained dual-armed cluster tools that have diverse wafer flow patterns. We propose a systematic method of determining the schedulable process time range for which there exists a feasible schedule that satisfies the time constraints. We explain how to select the desirable process times within the schedulable process time range. We present a method of determining the tool operation schedule. For more flexible scheduling under the time constraints, we propose a modification of the conventional swap operation in order to allow wafer delay on a robot arm during a swap operation. We compare the performance of the new swap strategy with that of the conventional swap strategy.

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