Electromigration reliability for a tungsten-filled via hole structure

Matsuoka, F.; Hama, K.; Nakata, R.; Maeguchi, K.; Kanzaki, K.

doi:10.1109/16.47758

Cited by 26 publications

(5 citation statements)

References 4 publications

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“…[22][23][24][25] Furthermore, the tungsten-filled via and the aluminum wire layers are electrically connected with higher reliability than the copper or aluminum plug. [26][27][28] The via resistance was 2.5 ³ measured at room temperature. The heater was located directly under the DUT, isolated from the DUT by an ILD.…”

Section: Introductionmentioning

confidence: 99%

“…In our 0.25-µm-rule BiCD process, the tungsten-filled via was introduced because it is a solution to the problems of metallization such as insulator layer planarization and contact failure [22][23][24][25]. Furthermore, the tungsten-filled via and the aluminum wire layers are electrically connected with higher reliability than the copper or aluminum plug [26][27][28]. The via resistance was 2.5 ³ measured at room temperature.…”

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confidence: 99%

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Reliability study of thermal cycling stress on smart power devices

Zhang

Yoshihisa

Furuya

et al. 2014

Jpn. J. Appl. Phys.

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In this paper, we describe a smart power device degradation behavior under thermal cycling stress. An innovative test structure was developed, which faithfully reflects a stress state caused by the smart power device during operation. From our experiment, the device degraded after millions of fast thermal cycling pulses. We discovered that via destruction was the cause of the device degradation. For the duration of thermal cycling stress, the via resistance increased gradually, and finally increased rapidly at the point of millions of cycles. A failure via was observed, which was broken into two parts. Therefore, the via disconnection was considered to be due to thermo-mechanical stress or electro-migration. Some experiments were conducted, and we demonstrated that the via destruction dominated to the thermo-mechanical stress introduced by the thermal cycling stress.

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Reliability study of thermal cycling stress on smart power devices

Zhang

Yoshihisa

Furuya

et al. 2014

Jpn. J. Appl. Phys.

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“…The EM lifetime of multilevel metallization systems with W-plug vias has been reported to be much shorter than that of a single-level Al stripe [1] even after titanium layering was introduced to improve via EM performance [2]. Researchers have proposed different via failure mechanisms such as an atomic flux divergence due to material discontinuity, damages caused by via etch, current crowding, local depletion of dopants at the W/Al interface, etc [3][4][5][6]. Microstructurally, the position of Al grain boundaries relative to the via could have an impact on via EM performance [7].…”

Section: Introductionmentioning

confidence: 99%

The dependence of W-plug via EM performance on via size

Le¹,

Banerjee²,

McPherson³

1996

Semicond. Sci. Technol.

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The electromigration (EM) performance of W-plug vias of different sizes, different capping layer types and electron flow directions in a multilevel metallization system was investigated. When the electron flow direction was from metal 2 to metal 1, with a TiN-capped metallization system, the time-to-failure dispersion (sigma) was greatly influenced by via size. However, when the electron flow direction was from metal 1 to metal 2, there was little dependence on via size. Similarly, the via EM performance of a metallization system with titanium as a part of the capping layer exhibited no dependence on via size.

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“…Therefore sites D and B (see [76][77][78][79][80][81][82]. Therefore, the experimental results suggest that EWF might not be the only driving force in the EM failure process.…”

Section: Results and Discussion On Line-via Emmentioning

confidence: 99%

“…(6.1) and significant deviations are also predicted from this simple relationship[101][102][103][104][105]. Thus in a bent conductor such as in a line-via structure, due to the non-uniform distribution of the current density, deviation in Black's relation is expected.Though current crowding in Al-based line-via structure was studied in 1990s[76], studies on current crowding for Cu-based metallization are hardly found. It is to be noted here that the cylindrical via (which connects the M1 and M2 lines) is an integral part of the M2 metallization for Cu based DD line-via structure and which is not true for case with Al-based metallization.It is the purpose of this chapter to investigate the EM characteristics of two different line widths considering Cu DD line-via interconnects.…”

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confidence: 99%

A study on electromigration by driving force approach for submicron copper interconnect

Roy¹

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Electromigration (EM) is one of the major reliability issues for metal interconnect in integrated circuits (ICs). The ever increasing complexity of interconnects requires more demanding reliability of each component. The prime interest of this work is to investigate the EM failure physics for submicron Cu interconnections based on driving force approach including the effect of surrounding materials. For EM in interconnect, there are various extrinsic weaknesses which are having significant impact on failure characteristics. One good example of extrinsic weakness is stress gradient which exists in the interconnect core material due to thermo-mechanical mismatch at typical EM test condition. From the very beginning of the EM history, the electron wind force (EWF) is believed to be the most responsible driving force for atom or vacancy migration, although it is well known that the surrounding materials and the interconnect processing history highly influence the failure mechanisms. Apart from the EWF, the other driving forces such as forces from stress gradient, temperature gradient, surface tension etc. are believed to be only modify the atomic flux (AF) and corresponding atomic flux divergence (AFD) created by EWF. It is the purpose of this study to verify that the above mentioned forces can act as potential driving force in EM. The obvious sources of AFDs are the non-uniform distributions of current density, temperature, and stress fields in the metallization. These non-uniformities arise due to the presence dissimilar materials surrounding the ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library VII metallization and hence responsible for various extrinsic weakness against EM mass transport. In investigating the EM failure physics, the key reliability process parameters are identified to improve the EM reliability. In order to investigate the various driving forces and their effects on EM reliability for submicron interconnects, AFD based model is developed using finite element method. By introducing the above mentioned combined driving force approach and conducting EM experiments for submicron Cu interconnects, various EM characteristics are described. The model predicts that the stress free temperature (SFT) is one of the important process-related parameter that influences interconnect EM reliability. It is also predicted that by lowering the SFT, EM lifetime can be improved, which is verified by conducting EM experiments. In order to obtain critical void volume, resistance change profile etc., a dynamic EM model is described for submicron Cu dual damascene (DD) line-via test structure. The model predictions are found to agree well with experimental results. One of the EM reliability concern is the current crowding in line-via interconnects. The effect of current crowding is described in the light of width dependence and EM failure characteristics. A modified Black's equation is prescribed for line-via interconnects in the presence of current crow...

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Electromigration reliability for a tungsten-filled via hole structure

Cited by 26 publications

References 4 publications

Reliability study of thermal cycling stress on smart power devices

Reliability study of thermal cycling stress on smart power devices

The dependence of W-plug via EM performance on via size

A study on electromigration by driving force approach for submicron copper interconnect

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