Copper CMP integration and time dependent pattern effect

Pan, Jianbing; Li, Ping; Wijekoon, K.; Tsai, Stan; Redeker, Fritz

doi:10.1109/iitc.1999.787110

Cited by 14 publications

(16 citation statements)

References 2 publications

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“…The same set of experimental data (Pan et al [7]) and , values are used in this simulation. The comparison is shown in Fig.…”

Section: B Dishing Versus Linewidthmentioning

confidence: 99%

“…The experimental data for copper dishing (Pan et al [7]) is used in the simulation and the experiment is carried out on patterned wafers using Mirra CMP system with three polish platens and an In Situ-Rate-Monitor (ISRM) on each platen. The model predictions are compared to experimental data by fitting a single data point corresponding to the dishing limit to the model.…”

Section: A Dishing Versus Timementioning

confidence: 99%

“…Model prediction compared with experimental data (Pan et al[7]) for dishing versus overpolishing curve.…”

mentioning

confidence: 98%

“…1). Metal dishing and dielectric erosion will lead to line resistance deviation from its intended value and the resulting surface topography will lead to additional difficulty for the next level metal line fabrication (e.g., Pan et al [7]). …”

mentioning

confidence: 99%

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An analytical dishing and step height reduction model for chemical mechanical planarization (CMP)

Chandra

2003

IEEE Trans. Semicond. Manufact.

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An analytical model for dishing and step height reduction in chemical mechanical planarization (CMP) is presented. The model is based on the assumption that at the feature scale, high areas on the wafer experience higher pressure than low areas. A Prestonian material removal model is assumed. The model delineates how dishing and step height reduction depend on slurry properties (selectivity and Preston's constants), pad characteristics (stiffness and bending ability), polishing conditions (pressure, relative velocity and overpolishing) and wafer surface geometry (linewidth, pitch and pattern density). Model predictions are in good agreement with existing experimental observations. The present model facilitates understanding of the CMP process at the feature scale. Based on the proposed model, design avenues for decreasing dishing and increasing the speed of step height reduction may be explored through modification of appropriate parameters for slurry, pad and polishing conditions. The proposed model may also be used as a design tool for pattern layout to optimize the performance of the CMP process.

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“…The same set of experimental data (Pan et al [7]) and , values are used in this simulation. The comparison is shown in Fig.…”

Section: B Dishing Versus Linewidthmentioning

confidence: 99%

Section: A Dishing Versus Timementioning

confidence: 99%

“…Model prediction compared with experimental data (Pan et al[7]) for dishing versus overpolishing curve.…”

mentioning

confidence: 98%

mentioning

confidence: 99%

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An analytical dishing and step height reduction model for chemical mechanical planarization (CMP)

Chandra

2003

IEEE Trans. Semicond. Manufact.

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“…Copper chemical-mechanical planarization (CMP) is an integral component of the Damascene flow to planarize the deposited copper film and remove the overburden outside the patterned trenches. However, line width and pattern density dependencies of copper CMP introduce a significant sheet resistance variation across the die [2], [3]. The effect of such an intra-die variation is twofold.…”

Section: Introductionmentioning

confidence: 99%

Electrical characterization of the copper cmp process and derivation of metal layout rules

Lakshminarayanan¹,

Wright²,

Pallinti³

2003

IEEE Trans. Semicond. Manufact.

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Design rules were developed for the layout of copper Damascene interconnect layers to minimize the within-die resistance variation. The impact of various layout configurations on the metal sheet resistance was characterized using two different test vehicles. An increase in resistance was observed on wide lines and high pattern densities due to dishing and dielectric erosion, respectively. In addition to the above, narrow lines were severely impacted by the presence of wide adjacent features in close proximity. The pattern interaction distance for copper chemical-mechanical planarization (CMP) was calculated by analyzing the resistance variation at the edge of a density or width transition. In this work, the interaction distance was found to be on the order of 25 m (as opposed to a few millimeters for oxide CMP). From these results, a window of about 50 to 60 m was found to be necessary to obtain the effective pattern density for copper CMP. The resistance of the upper metal level was a strong function of the underlying layer density. Hence, multilevel pattern dependencies have to be considered when modeling and predicting the line resistance on a real design. However, unlike oxide polish, pattern density alone is insufficient to predict the final copper thickness. Width-dependent spacing rules are necessary to prevent clustering of features (narrow lines very close to wide buses) and avoid regions of very low density.

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Effects of pattern characteristics on copper CMP

Ruan

Chen

et al. 2009

J. Semicond.

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Copper chemical mechanical polishing (CMP) is influenced by geometric characteristics such as line width and pattern density, as well as by the more obvious parameters such as slurry chemistry, pad type, polishing pressure and rotational speed. Variations in the copper thickness across each die and across the wafer can impact the circuit performance and reduce the yield. In this paper, we propose a modeling method to simulate the polishing behavior as a function of layout pattern factors. Under the same process conditions, the pattern density, the line width and the line spacing have a strong influence on copper dishing, dielectric erosion and topography. The test results showed: the wider the copper line or the spacing, the higher the copper dishing; the higher the density, the higher the dielectric erosion; the dishing and erosion increase slowly as a function of increasing density and go into saturation when the density is more than 0.7.

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Copper CMP integration and time dependent pattern effect

Cited by 14 publications

References 2 publications

An analytical dishing and step height reduction model for chemical mechanical planarization (CMP)

An analytical dishing and step height reduction model for chemical mechanical planarization (CMP)

Electrical characterization of the copper cmp process and derivation of metal layout rules

Effects of pattern characteristics on copper CMP

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