Endpoint Detection in Cu-CMP

Kondoju, Siddartha; Juncker, Christophe; Lucas, Pierre; Raghavan, S.; Fischer, P.; Oehler, A.; Moinpour, Mansour

doi:10.1149/1.2218270

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…Also, for materials such as silicon oxynitride used with an underlying silicon nitride stop layer, the difference in optical properties may not be sufficiently large for the optical method to identify the end point. One may have to rely on fluorescence 115 or temperature 116 as a parameter to identify the end point.…”

Section: Current Challengesmentioning

confidence: 99%

Shallow Trench Isolation Chemical Mechanical Planarization: A Review

Ramanathan

Dandu

Babu

2015

ECS J. Solid State Sci. Technol.

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Electrical isolation of the billion or so active components in each integrated device is achieved using shallow trench isolation (STI) which requires chemical mechanical planarization (CMP) involving silicon dioxide removal at a high rate and stopping on an underlying silicon nitride film. Several colloidal slurries with various additives can yield the desired high rate selectivity between the oxide and nitride films during CMP while maintaining an acceptably low nitride rate. Here, many of such high selectivity STI CMP slurries described in the literature are reviewed along with the characteristics of the colloidal dispersions like the abrasives, additives, the interactions between them and with the films being planarized and the associated pH range in which the high selectivity is observed. The mechanisms proposed to explain the high reactivity of ceria with oxide, the role of additives in suppressing the nitride removal rate and resulting high selectivity are discussed. Reduction of a multitude of defects in post-CMP processed STI structures still remains an important challenge, especially as the feature sizes continue to shrink. Chemical mechanical planarization (CMP) is one of the important enabling processes in facilitating multilevel metallization (in some cases reaching up to 14 levels) and incorporation of novel gate and channel materials at the component level in modern semiconductor device manufacturing where its use has become widespread and ubiquitous.1-6 Here, we review recent advances and remaining challenges in one specific application of CMP, the shallow trench isolation (STI) process. STI is a method of electrically isolating active areas using trenches created in the Si substrate around the active elements and filling it with an insulating dielectric, such as silicon dioxide or silicon oxy-nitride or silicon carbonitride.7-11 Process details of the STI structures are available in numerous publications. There are a multitude of techniques available for oxide deposition and even though the resulting oxides have very different properties, for simplicity we do not distinguish between them in this review. For completeness and ease of reference, a schematic representation of the STI process is given in Figure 1. While the trenches are being filled, silicon dioxide also deposits over unwanted areas on the entire wafer (since selective deposition in trenches only is not possible) creating an uneven topography. The excess and unwanted oxide has to be completely removed and CMP has proven to be the only viable and robust global and local planarization capable process technology.Here, as shown in Figure 1, presence of a very thin silicon nitride stop layer (deposited on another thin pad oxide layer to control film stress) is an essential and integral part of the process. This nitride stop layer prevents any damage during planarization to the all-important epitaxially grown surface underneath and is itself removed by a wet etch process subsequent to the overburden oxide removal. Since the integrity of the...

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Section: Current Challengesmentioning

confidence: 99%

Shallow Trench Isolation Chemical Mechanical Planarization: A Review

Ramanathan

Dandu

Babu

2015

ECS J. Solid State Sci. Technol.

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“…CMP was originally used for glass and silicon wafer polishing (9). As its functionality increases, the CMP process has been adapted to copper (Cu) (10,11) , tungsten (W) (12,13), and low k dielectric (14) in the semiconductor processing. The goal of CMP is to achieve planarization of rough surfaces.…”

Section: ___________mentioning

confidence: 99%

Interfacial Forces in Chemical-Mechanical Polishing

Liang

2009

Advanced Tribology

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The demand for microelectronic device miniaturization requires new concepts and technology improvement in the integrated circuits fabrication. In last two decades, Chemical-Mechanical Polishing (CMP) has emerged as the process of choice for planarization. The process takes place at the interface of a substrate, a polishing pad, and an abrasive containing slurry. This synergetic process involves several forces in multilength scales and multi-mechanisms. This research contributes fundamental understanding of surface and interface sciences of microelectronic materials with three major objectives. In order to extend the industrial impact of this research, the chemical-mechanical polishing (CMP) is used as a model system for this study. The first objective of this research is to investigate the interfacial forces in the CMP system. For the first time, the interfacial forces are discussed systematically and comparatively so that key forces in CMP can be pinpointed. The second objective of this research is to understand the basic principles of lubrication, i.e., fluid drag force that can be used to monitor, evaluate, and optimize CMP processes. New parameters were introduced to include the change of material properties during CMP. Using the experimental results, a new equation was developed to understand the principle of lubrication behind the CMP. The third objective is to study the synergy of those interfacial forces with electrochemistry. The electro-chemical-mechanical polishing (ECMP) of copper was studied. Experiments were conducted on the tribometer in combination with a potentiostat. Friction coefficient was used to monitor the polishing process and correlated with the wear behavior of post-CMP samples. Surface characterization was performed using AFM, SEM, and XPS techniques. Results from experiments were used to generate a new wear model, which provided insight from CMP iv mechanisms. The ECMP is currently the newest technique used in the semiconductor industries. This research is expected to contribute to the CMP technology and improve its process performance. This dissertation consists of six chapters. The first chapter covers the introduction and background information of surface forces and CMP. The motivation and objectives are discussed in the second chapter. The three major objectives which include approaches and expected results are covered in the next three chapters. Finally chapter VI summarizes the major discovery in this research and provides some recommendations for future work. v DEDICATION To my mother, for her unconditional love, affection and support. vi ACKNOWLEDGEMENTS First and foremost, I would like to express my deepest gratitude to my academic advisor, Dr. Hong Liang. She taught me how to become a good researcher and provided an independent environment to assist my growth. She also gave me countless supports and encouragements during my last four years of study at Texas A&M University. I also want to thank her for her great patience and invaluable directions in the preparation of this dis...

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Development of endpoint detection using optical transmittance and magnetic permeability based on skin effect in chemical mechanical planarization

Fujita

Kitade

2019

Precision Engineering

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Endpoint Detection in Cu-CMP

Cited by 3 publications

References 4 publications

Shallow Trench Isolation Chemical Mechanical Planarization: A Review

Shallow Trench Isolation Chemical Mechanical Planarization: A Review

Interfacial Forces in Chemical-Mechanical Polishing

Development of endpoint detection using optical transmittance and magnetic permeability based on skin effect in chemical mechanical planarization

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