Tungsten corrosion and recess improvement by feasible slurry and clean chemical in WCMP process

Chen, Kuang-Wei; Chen, Chun-Fu; Hung, Yung-Tai; Luoh, Tuung; Yang, Lin‐An; Yang, Tahone; Chen, Kuang-Chao

doi:10.1109/iitc-amc.2017.7968980

Cited by 5 publications

(4 citation statements)

References 3 publications

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“…The known mechanism of tungsten void defect cannot explain why it has strong brush lifetime dependency. 11,12,14,15 This paper suggests that brush friction force contributed a lot to the formation of tungsten void defect, which can explain brush lifetime effect at CMP in-situ cleaner module.…”

Section: Resultsmentioning

confidence: 79%

“…The source of tungsten void defect and its formation mechanism has been reported several times. 11,12,14,15 Chiu et al suggests optical energy induced voltage difference at P+/N-well as tungsten plug corrosion mechanism. 12 They also proposed q-time effect on electrochemical reaction of tungsten plug.…”

mentioning

confidence: 99%

“…11 K-W Chen et al showed that tungsten plug recess was strongly dependent on the underlying metal line area and layout design. 14 Most explanations on tungsten void focuses on corrosion effect and corrosion mechanism. Thus, the approach has been limited to polishing slurry chemistry and post CMP in-situ cleaning chemical properties.…”

mentioning

confidence: 99%

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A New Approach to the Formation Mechanism of Tungsten Void Defect in Chemical Mechanical Polishing

Kim¹,

Egan²,

Shi³

et al. 2018

ECS J. Solid State Sci. Technol.

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The advanced node semiconductor device fabrication needs tungsten chemical mechanical polishing as a critical process to enable transistor formation as well as metal interconnection. Accordingly, CMP induced defect concerns have drawn attention to the process integration. Tungsten voids by CMP are one of the major defects to detract device yield. Their formation mechanism has been known as electrochemical corrosion or an optical induced corrosion phenomenon associated with polishing slurry chemistry. However, this paper proposes a new mechanism of tungsten void formation. Different from known corrosion mechanisms, it is observed that tungsten void frequency has strong correlation with CMP in-situ cleaner brush lifetime. At early brush life, tungsten void forms more frequently. Moreover, this paper reveals that CMP brush cleaning play a critical role in the formation of tungsten voids. Tungsten etch rate dependence on brush condition, tungsten void defect density correlation to brush life, and surface chemical analysis of tungsten blanket wafers show that tungsten voids are induced by combined effect of friction force and oxidation in brush cleaner module, which is a new approach to the formation mechanism of tungsten void defect.

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Section: Resultsmentioning

confidence: 79%

mentioning

confidence: 99%

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A New Approach to the Formation Mechanism of Tungsten Void Defect in Chemical Mechanical Polishing

Kim¹,

Egan²,

Shi³

et al. 2018

ECS J. Solid State Sci. Technol.

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“…Similar phenomena have been reported in W CMP and Cu CMP, but their frequency has been limited. [4][5][6][7][8][9] These phenomena are observed only on the pattern wafer in the pilot stage or production stage, so it is almost impossible for slurry makers, CMP hardware makers, CMP pad makers, research institutes, and schools to observe such instances of abnormal W plug oxidation. In this study, patterned wafers in production were inspected for abnormal oxidation to determine the step of the CMP process in which the phenomenon occurs, in what plug shapes it causes failure, why this phenomenon occurs, and how to solve it.…”

mentioning

confidence: 99%

Study on Abnormally Accelerated Oxidation of Tungsten Plugs during Tungsten Chemical Mechanical Polishing in Semiconductor Manufacturing

Hwang¹,

Jeon²,

Hong³

et al. 2021

ECS J. Solid State Sci. Technol.

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The root cause of the abnormally accelerated oxidation behavior occurring in tungsten (W) chemical mechanical polishing (CMP) has been performed to provide guidance to those developing practical solutions. Abnormal oxidation behavior refers to the case where the surrounding W contact plugs are normal, but oxidation occurs rapidly and abruptly only at a specific contact, causing device failure. For this study, the failure location was determined through a wafer-level probe test of fully processed DRAM device wafers. With this specific location information, a top-down view inspection was performed on the location immediately after CMP to assess the characteristics, and then a wafer-level probe test was conducted to confirm the failure. In this way, the top-down view plug images immediately after CMP and their potential failure were classified. Based on these results, the CMP process step involving abnormal oxidation was determined, as were the conditions needed to cause abnormal oxidation. Potential solutions to abnormal oxidation are presented based on our results.

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Study and Improvement on Tungsten Recess in CMP Process

Zhang

Zhu

Fang

2019

2019 China Semiconductor Technology International Conference (CSTIC)

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Tungsten corrosion and recess improvement by feasible slurry and clean chemical in WCMP process

Cited by 5 publications

References 3 publications

A New Approach to the Formation Mechanism of Tungsten Void Defect in Chemical Mechanical Polishing

A New Approach to the Formation Mechanism of Tungsten Void Defect in Chemical Mechanical Polishing

Study on Abnormally Accelerated Oxidation of Tungsten Plugs during Tungsten Chemical Mechanical Polishing in Semiconductor Manufacturing

Study and Improvement on Tungsten Recess in CMP Process

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