Assessing and characterizing inter-and intra-die variation using a statistical metrology framework: A CMP case study

Divecha, R.; Stine, B.E.; Chang, E.; Ouma, Dennis; Boning, Duane S.; Chung, J.E.; Nakagawa, O.S.; Oh, Soo‐Young; Prasad, Sharad; Kapoor, A.

doi:10.1016/s0920-5489(99)92266-3

Cited by 9 publications

(4 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: 66%

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

Stine

Ouma

Divecha

et al. 1998

IEEE Trans. Semicond. Manufact.

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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: 66%

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

Stine

Ouma

Divecha

et al. 1998

IEEE Trans. Semicond. Manufact.

Self Cite

119

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“…The improvements in dielectric thickness uniformity observed in metal-fill experiments can ultimately be attributed to layout pattern-density. The strong correlation between layout pattern density and dielectric thickness is well recognized for CMP processes [11], [13]- [16], and it has also been demonstrated that layout pattern-density is the primary variable controlling CMP-induced intradie dielectric thickness variation [11], [14]. Pattern density can be defined as the ratio of raised oxide area in a given square window to the area of the window.…”

Section: Mechanisms For Metal-fill Patterning Benefitsmentioning

confidence: 99%

The physical and electrical effects of metal-fill patterning practices for oxide chemical-mechanical polishing processes

Stine¹,

Boning

Chung

et al. 1998

IEEE Trans. Electron Devices

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149

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In oxide chemical-mechanical polishing (CMP) processes, layout pattern dependent variation in the interlevel dielectric (ILD) thickness can reduce yield and impact circuit performance. Metal-fill patterning practices have emerged as a technique for substantially reducing layout pattern dependent ILD thickness variation. We present a generalizable methodology for selecting an optimal metal-fill patterning practice with the goal of satisfying a given dielectric thickness variation specification while minimizing the added interconnect capacitance associated with metal-fill patterning. Data from two industrialbased experiments demonstrate the beneficial impact of metalfill on dielectric thickness variation, a 20% improvement in uniformity in one case and a 60% improvement in the other case, and illustrate that pattern density is the key mechanism involved. The pros and cons of two different metal-fill patterning practices-grounded versus floating metal-are explored. Criteria for minimizing the effect of floating or grounded metal-fill patterns on delay or crosstalk parameters are also developed based on canonical metal-fill structures. Finally, this methodology is illustrated using a case study which demonstrates an 82% reduction in ILD thickness variation. Index Terms-Chemical-mechanical polishing (CMP), design for manufacturing, metal-fill, within-die variation. I. INTRODUCTION I N recent years, chemical-mechanical polishing (CMP) has emerged as the primary technique for planarizing interlayer dielectrics [1], [2]. Although CMP is very effective at reducing the as-deposited step height and achieves a measure of global planarization not possible with either spin-on or resist etchback Manuscript

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“…Initial investigations of oxide thickness included development of a fingered electrical capacitive test structure, as illustrated in Fig. 4, from which the oxide thickness between two metal layers could be inferred using TCAD tools in conjunction with a large volume of electrical probe measurements (5)(6)(7)(8)11).…”

Section: A Test Structure Designmentioning

confidence: 99%

“…As discussed in (8), three stages of experimental design have been pursued in understanding variation. In the first stage, "screening" experiments seeks to explore a large space of possible layout or process factors that might influence the parameter of interest.…”

Section: Design Of Experiments Phasesmentioning

confidence: 99%

Statistical metrology—measurement and modeling of variation for advanced process development and design rule generation

Boning¹,

Chung²

1998

The 1998 International Conference on Characterization and Metrology for ULSI Technology

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Assessing and characterizing inter-and intra-die variation using a statistical metrology framework: A CMP case study

Cited by 9 publications

References 0 publications

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

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

The physical and electrical effects of metal-fill patterning practices for oxide chemical-mechanical polishing processes

Statistical metrology—measurement and modeling of variation for advanced process development and design rule generation

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