Semi-empirical modelling of SiO/sub 2/ chemical-mechanical polishing planarization

Burke, Peter

doi:10.1109/vmic.1991.153031

Cited by 15 publications

(7 citation statements)

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“…As reported in the literature [3], [4], [14], [15], [24] and apparent from a visual inspection of the data (Figs. 4 and 5), the ILD thickness is quite sensitive to pattern density.…”

Section: A Pattern Density Modelingsupporting

confidence: 62%

“…SRAM or gate array cells are sometimes used [12], [13]. Burke [3] used a set of two test masks but does not describe their design or construction. With a few exceptions, these masks and accompanying analysis techniques are not discussed fully or at all, and appear primarily targeted at testing specific models rather than to aid in characterizing or generating models.…”

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confidence: 99%

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Rapid characterization and modeling of pattern-dependent variation in chemical-mechanical polishing

Stine

Ouma

Divecha

et al. 1998

IEEE Trans. Semicond. Manufact.

119

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Pattern-dependent effects are a key concern in chemical-mechanical polishing (CMP) processes. In oxide CMP, variation in the interlevel dielectric (ILD) thickness across each die and across the wafer can impact circuit performance and reduce yield. In this work, we present new test mask designs and associated measurement and analysis methods to efficiently characterize and model polishing behavior as a function of layout pattern factors-specifically area, pattern density, pitch, and perimeter/area effects. An important goal of this approach is rapid learning which requires rapid data collection. While the masks are applicable to a variety of CMP applications including back-end, shallow-trench, or damascene processes, in this study we focus on a typical interconnect oxide planarization process, and compare the pattern-dependent variation models for two different polishing pads. For the process and pads considered, we find that pattern density is a strongly dominant factor, while structure area, pitch, and perimeter/area (aspect ratio) play only a minor role.

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“…As reported in the literature [3], [4], [14], [15], [24] and apparent from a visual inspection of the data (Figs. 4 and 5), the ILD thickness is quite sensitive to pattern density.…”

Section: A Pattern Density Modelingsupporting

confidence: 62%

mentioning

confidence: 99%

Rapid characterization and modeling of pattern-dependent variation in chemical-mechanical polishing

Stine

Ouma

Divecha

et al. 1998

IEEE Trans. Semicond. Manufact.

119

View full text Add to dashboard Cite

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“…Chemical mechanical planarization (CMP) has the capability to achieve adequate local and global planarization necessitated by stringent future submicrometer very large scale integration (VLSI) requirements. [1][2][3] CMP is now widely accepted for planarizing interlevel dielectrics 4,5 and forming inlaid metal patterns. [6][7][8] Figure 1 shows a schematic representation of the CMP process.…”

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confidence: 99%

Two‐Dimensional Wafer‐Scale Chemical Mechanical Planarization Models Based on Lubrication Theory and Mass Transport

Sellamanickam

Thakurta

Schwendeman³

et al. 1999

J. Electrochem. Soc.

133

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The effects of the variation of chemical mechanical planarization (CMP) process parameters on slurry hydrodynamics and removal rate are studied using physically based models. The two models which are developed to describe and fundamentally understand the CMP process are (i) the lubrication model for slurry flow and (ii) the mass transport model for material removal. The mass transport model is developed for copper CMP. Conditions for stable operation and reduced wafer scratching are identified from the lubrication model. The mass transport model takes into account the chemical reaction at the wafer surface, the slurry flow hydrodynamics, and the presence of abrasive particles. The polish rates predicted by the model agree well with those measured experimentally.

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“…An alternative model for the dependence of local step height reduction has been proposed by numerous workers, including Burke [6], and Tseng [7]. In this case, it is proposed that the rate of step height reduction is proportional to the remaining step height.…”

Section: Integrated Model: Effective Density and Step Heightmentioning

confidence: 99%

Pattern Dependent Modeling for CMP Optimization and Control

et al. 1999

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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...

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Semi-empirical modelling of SiO/sub 2/ chemical-mechanical polishing planarization

Cited by 15 publications

References 1 publication

Rapid characterization and modeling of pattern-dependent variation in chemical-mechanical polishing

Rapid characterization and modeling of pattern-dependent variation in chemical-mechanical polishing

Two‐Dimensional Wafer‐Scale Chemical Mechanical Planarization Models Based on Lubrication Theory and Mass Transport

Pattern Dependent Modeling for CMP Optimization and Control

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