Run by run control of chemical-mechanical polishing

Boning, Duane S.; Moyne, William P.; Smith, T.; Moyne, James; Trelfeyan, R.; Hurwitz, Arnon M.; Sellman, S.; Taylor, John E.

doi:10.1109/iemt.1995.526097

Cited by 65 publications

(43 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…control problem that appears in semiconductor manufacturing where batch processing is the norm; see [41], [42], [43], [44]. The loop-shaping procedure is done using the normalized coprime factorization ℋ ∞ design methods of Glover and…”

Section: More Recent Work Done By Tsakalis Et Al [11] [4] [12] [13] Umentioning

confidence: 99%

Discrete-Time PID Controller Tuning Using Frequency Loop-Shaping.

Ashfaque

Tsakalis

2012

IFAC Proceedings Volumes

View full text Add to dashboard Cite

i ABSTRACT Proportional-Integral-Derivative (PID) controllers are a versatile category of controllers that are commonly used in the industry as control systems due to the ease of their implementation and low cost. One problem that continues to intrigue control designers is the matter of finding a good combination of the three parameters -P, I and D of these controllers so that system stability and optimum performance is achieved. Also, a certain amount of robustness to the process is expected from the PID controllers. In the past, many different methods for tuning PID parameters have been developed. Some notable techniques are the ZieglerNichols, Cohen-Coon, Astrom methods etc. For all these techniques, a simple limitation remained with the fact that for a particular system, there can be only one set of tuned parameters; i.e. there are no degrees of freedom involved to readjust the parameters for a given system to achieve, for instance, higher bandwidth. Another limitation in most cases is where a controller is designed in continuous time then converted into discrete-time for computer implementation. The drawback of this method is that some robustness due to phase and gain margin is lost in the process.In this work a method of tuning PID controllers using a loop-shaping approach has been developed where the bandwidth of the system can be chosen within an

show abstract

Section: More Recent Work Done By Tsakalis Et Al [11] [4] [12] [13] Umentioning

confidence: 99%

Discrete-Time PID Controller Tuning Using Frequency Loop-Shaping.

Ashfaque

Tsakalis

2012

IFAC Proceedings Volumes

View full text Add to dashboard Cite

show abstract

“…Various strategies have emerged to address this concern, including ex-situ and in-situ pad conditioning, and run by run control. In previous work, we have demonstrated run by run control on blanket wafers, in which polish time and other process parameters are adjusted for the next or later wafer based on measurements on a previous wafer to compensate for removal rate and uniformity degradation [10,11]. In practical use, however, such run by run control faces additional barriers to adoption.…”

Section: Ild Cmp Run By Run Controlmentioning

confidence: 99%

Pattern Dependent Modeling for CMP Optimization and Control

et al. 1999

Self Cite

View full text Add to dashboard Cite

In previous work, we have formalized the notions of "planarization length" and "planarization response function" as key parameters that characterize a given CMP consumable set and process. Once extracted through experiments using carefully designed characterization mask sets, these parameters can be used to predict polish performance in CMP for arbitrary product layouts. The methodology has proven effective at predicting oxide interlevel dielectric planarization results.In this work, we discuss extensions of layout pattern dependent CMP modeling. These improvements include integrated up and down area polish modeling; this is needed to account for both density dependent effects, and step height limits or step height perturbations on the density model. Second, we discuss applications of the model to process optimization, process control (e.g. feedback compensation of equipment drifts), and shallow trench isolation (STI) polish. Third, we propose a framework for the modeling of pattern dependent effects in copper CMP. The framework includes "removal rate diagrams" which concisely capture dishing height and step height dependencies in dual material polish processes. I. MOTIVATION: PATTERN DEPENDENT CMP CONCERNSThe motivation for this work is the presence of substantial pattern dependencies in CMP. As illustrated in Fig. 1, these concerns arise in a variety of key CMP process applications. In oxide or interlevel dielectric (ILD) CMP, the global planarity or oxide thickness differences in different regions across the chip is a key concern. In addition, the remaining local step height (or height differences in the oxide over patterned features and between patterned features) may also be of concern, although such local step heights are typically small compared to the global nonplanarity across the chip resulting from pattern density dependent planarization. In shallow trench isolation (STI), one is typically concerned about dishing within oxide features resulting from over-polish, as well as the erosion of supporting nitride and in some cases the details of the corner rounding near active areas. In metal polishing (such as in copper damascene), one is concerned also with dishing into metal lines, as well as the erosion of supporting oxide or dielectric spaces in arrays between lines.In this paper, we begin by reviewing previous work on characterization and modeling of oxide CMP pattern dependencies. In Section II, we review the density-dependent oxide CMP model, as well as the important determination of "effective density" based upon a planarization length or planarization response function determination. In Section III, we also review a recent advance in oxide modeling, through which a step height dependent model (proposed elsewhere) has been integrated with the effective density model to produce an integrated time-evolution model for improved accuracy in step height and down area polish prediction. In Section IV we present example applications of the oxide characterization and modeling methodology. These inclu...

show abstract

“…This need has originated a collection of techniques called RtR control (Baras & Patel, 1996;Sachs, Hu, & Ingolfsson, 1995;Boning, Moyne, & Smith, 1995;Castillo & Yeh, 1998;Hankinson, Vincent, Irani, & Khargonekar, 1997;Ingolfsson & Sachs, 1993;Ning, 1996;Deng, 1999). RtR control is a form of discrete-time process control in which the product recipe with respect to a particular equipment process is modiÿed ex situ, i.e.…”

Section: Introductionmentioning

confidence: 99%

Run-to-run control methods based on the DHOBE algorithm

Zhang¹,

Deng²,

Baras³

2003

Automatica

View full text Add to dashboard Cite

Since process models are typically not known exactly in real problems, it is important to estimate the process parameters before one applies the optimal control to a process. In this paper, the Dasgupta-Huang optimal bounding ellipsoid (DHOBE) algorithm is employed to estimate process parameters in semiconductor process run-to-run (RtR) control. At each iteration, the DHOBE algorithm returns an outer bounding ellipsoid of the likely process parameter set. If the vector center of the ellipsoid is taken as the estimate of the process parameter vector, then a model-reference controller results; if the vector within the ellipsoid that produces the worst expected cost is taken as the process parameter estimate, then a worst-case controller results. These two methods are compared with other RtR control schemes: the exponentially weighted moving average (EWMA) method and the optimizing adaptive quality controller (OAQC). Simulation results show that the performance of the model-reference RtR controller based on the DHOBE algorithm is comparable to or better than that of the other two RtR controllers in some speciÿc examples of semiconductor processes. ?

show abstract

Run by run control of chemical-mechanical polishing

Cited by 65 publications

References 13 publications

Discrete-Time PID Controller Tuning Using Frequency Loop-Shaping.

Discrete-Time PID Controller Tuning Using Frequency Loop-Shaping.

Pattern Dependent Modeling for CMP Optimization and Control

Run-to-run control methods based on the DHOBE algorithm

Contact Info

Product

Resources

About