Synergetic effects of wafer rigidity and retaining-ring parameters on contact stress uniformity in chemical mechanical planarization

Hu, Ian; Yang, Tian; Chen, Kuo-Shen

doi:10.1007/s00170-011-3215-8

Cited by 9 publications

(8 citation statements)

References 25 publications

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“…The pressure gradients were controlled dynamically by actuators, [37,38] or contact area. [39] Since the coefficient K is a constant value when the related parameters are determined and the V(x,y) has a linearly increasing relationship with r(x,y) in the radial direction, to achieve the purpose of uniform material removal, it is necessary to obtain a certain PPV. The distribution of the P(x,y) in the radial direction should be an inverse proportional function.…”

Section: Principle Analysismentioning

confidence: 99%

Contact stress prediction model of double‐layer elastomer with functionally graded and composite structure

et al. 2021

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As hard and brittle materials are widely used in the modern industry, it is essential to effectively achieve uniform material removal. In the present study, a contact stress prediction model for double-layer elastomer under uniform displacement load was proposed. It aims to predict the contact stress distribution based on the structure size and material parameters of the double-layer elastomer and optimize the relevant parameters to improve the uniformity of material removal. The functionally graded and composite structured lapping and polishing plate (FG/CS-LPP) was developed by mixing abrasive particles and rubber with different mass ratios to get different Young's moduli. Through optical microscope, the surface morphology was observed, and the mechanism of Young's modulus gradient change was demonstrated. After numerical simulation analysis, the effect of Young's modulus fluctuation on contact stress distribution trend was evaluated. As for the contact stress prediction model, an equivalent Young's modulus model and compensation function H(z) was introduced to simplify the analytical process. Further, the obtained equivalent equation was verified by simulations and experiments with an average percentage deviation of~2% and~6%, respectively. By fitting calculated and simulated values with a deviation of less than 5%, the compensation function H(z) was established. Finally, the contact stress prediction model was obtained and validated by simulations and experiments, the percentage deviation is less than 13%. Accordingly, the contact stress prediction model can provide a theoretical basis for FG/CS-LPP to achieve uniform material removal.

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Section: Principle Analysismentioning

confidence: 99%

Contact stress prediction model of double‐layer elastomer with functionally graded and composite structure

et al. 2021

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“…Therefore, a suction pressure is formed in the leading region of the wafer owing to a diverging clearance [65]. In the above models, the simplification of the carrier structure, especially the retaining ring, may obviously affect the contact feature of the wafer [9,10,67], which may further affect the slurry flow and the lubrication behavior between the wafer and pad. It is desired that more practical model considering the carrier structure and loading characteristic will be developed.…”

Section: Model Considering Fluid Mechanismmentioning

confidence: 99%

Chemical mechanical polishing: Theory and experiment

Zhao

2013

Friction

160

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For several decades, chemical mechanical polishing (CMP) has been the most widely used planarization method in integrated circuits manufacturing. The final polishing results are affected by many factors related to the carrier structure, the polishing pad, the slurry, and the process parameters. As both chemical and mechanical actions affect the effectiveness of CMP, and these actions are themselves affected by many factors, the CMP mechanism is complex and has been a hot research area for many years. This review provides a basic description of the development, challenges, and key technologies associated with CMP. We summarize theoretical CMP models from the perspectives of kinematics, empirical, its mechanism (from the viewpoint of the atomic scale, particle scale, and wafer scale), and its chemical-mechanical synergy. Experimental approaches to the CMP mechanism of material removal and planarization are further discussed from the viewpoint of the particle wear effect, chemical-mechanical synergy, and wafer-pad interfacial interaction.

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“…They were also used to analyze the effects of retaining ring on CMP performance. Hu [6] used two-dimensional models of fluid film lubrication and contact mechanics to calculate the contact stress and fluid pressure distribution on the wafer-pad interface in chemical mechanical polishing. They found that when the width and back pressure of retaining ring are properly chosen, the contact stress non-uniformity can be substantially reduced.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Slurry Flow and Contact Pressure in CMP Considering the Effects of Retaining Ring

Zhou

Jin

et al. 2016

AMR

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Retaining ring which keeps the wafer in place is an essential component in chemical mechanical polishing. Meanwhile, it helps to reduce the edge exclusion region where the material removal rate deviates significantly from that of the central region of the wafer. However, it may increase the slurry flow resistance and hence decrease the slurry flow rate. For properly designing a retaining ring of reasonable structure, the effects of retaining ring on slurry flow and contact pressure distribution in CMP process are analyzed by the mixed elastohydrodynamic lubrication model. It is found that the slurry flow is sensitive to the protrusion height of retaining ring used in the first generation carrier. The same as the first generation carrier, the slurry flow is obviously reduced with increasing pressure acting on the retaining ring in the second generation carrier. In addition, the floating retaining ring used in the second generation CMP carrier has better performance and is more controllable than the fixed retaining ring used in the first generation CMP carrier.

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Synergetic effects of wafer rigidity and retaining-ring parameters on contact stress uniformity in chemical mechanical planarization

Cited by 9 publications

References 25 publications

Contact stress prediction model of double‐layer elastomer with functionally graded and composite structure

Contact stress prediction model of double‐layer elastomer with functionally graded and composite structure

Chemical mechanical polishing: Theory and experiment

Numerical Analysis of Slurry Flow and Contact Pressure in CMP Considering the Effects of Retaining Ring

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