New Copper Alloy, Cu(SnN<sub>x</sub>), Films Suitable for More Thermally Stable, Electrically Reliable Interconnects and Lower-Leakage Current Capacitors

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In this study, we explore the potential of replacing the wetting and diffusion barrier layers in a conventional under bump metallurgy (UBM) structure, underneath flip-chip solder joints, with a buffer TiWN x -bearing Cu film deposited via cosputtering, viz., barrierless Si metallization, to reduce manufacturing, including soldering, costs in microelectronic manufacture. The introduced Cu(TiWN x ) films, after annealing at 700 C for 1 h, exhibit an excellent thermal stability on, and adhesion strength to, barrierless Si substrates, without detectable Cu/Si interfacial interactions and also display a solderability comparable to that of pure Cu. At 200 C, the Cu(TiWN x ) film within an Sn/Cu(TiWN x )/Si structure shows a dissolution rate that is lower than that of pure Cu by at least one order of magnitude, comparable to that of Ni in common solder joints. The Cu(TiWN x ) film thus seems to be a suitable candidate material for, at least, barrierless Si metallization and flip chip soldering.

Section: Introductionmentioning

confidence: 99%

Cu(TiWN_x) Film as a Barrierless Buffer Layer for Metallization Applications

Lin¹,

Chuang

Kao

2013

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“…Hence, the alloying of Cu with insoluble components has attracted several major applications and is crucial in materials science. Previous studies [6][7][8][9][10][11][12][13][14][15][16] have shown that Cu(ReN) 9) alloy films are thermally stable up to 730 C. Transition metal nitrides have also received great attention for their constructive properties and many technical applications. Koike and colleagues also developed Cu-Mn alloy films that were applied to interconnects in semiconductor manufacture.…”

Section: Introductionmentioning

confidence: 99%

A New Copper Alloy Film for Barrierless Si Metallization and Solder Bump Flip-Chip Application

Lin¹

2013

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In this study, a copper alloy, Cu(MnN x ), film is developed by cosputtering Cu and Mn on a barrierless Si substrate within an Ar/N 2 gas atmosphere. The resulting alloy film exhibits good thermal stability and adhesion to the substrate with no noticeable interactions between the film and the substrate after annealing at 700 C for 1 h, indicating that the film is thermally stable. The alloy film shall be able to replace both the wetting and diffusion layers for the flip-chip solder joints in conventional under bump metallurgy to reduce the manufacturing cost. We also observe that the Cu(MnN x ) alloy exhibits a solder ability comparable to that of pure Cu and a dissolution rate lower than that of pure Cu by at least one order of magnitude. The alloy's consumption rate is comparable to that of Ni, rendering the alloy a candidate material in both barrierless Si metallization and solder bump flip-chip application. #

“…Hence, the alloying of Cu with insoluble components has attracted several major applications and is crucial in materials science. Previous studies [5][6][7][8][9][10][11][12][13][14][15][16][17] have shown that Cu(ReN) 12) alloy films are thermally stable up to 730 C. Transition metal nitrides have also received great attention for their desirable properties and in many technical applications. Lin et al also developed Cu-Ir alloy films that were applied to interconnects in semiconductor manufacturing.…”

Section: Introductionmentioning

confidence: 99%

New Cu(TiIrN_x) Alloy Films for Solder Bump Flip-Chip Application

Lin¹

2013

Self Cite

A new copper alloy that shows fine thermal stability and adhesion to the substrate is developed in this study by cosputtering Cu, Ti, and Ir on a barrierless Si substrate within an Ar/N2 gas atmosphere to form a Cu(TiIrN x ) film. To reduce manufacture cost, we can replace both the wetting and diffusion layers underneath flip-chip solder joints in conventional under bump metallurgy with this thermally stable film, which exhibits weak, if any, interactions between the film and the substrate after annealing at 700 °C for 1 h. The alloy film's dissolution rate is lower than that of pure Cu by at least one order of magnitude, with a fine solderability similar to that of pure Cu. The film developed in this study seems to be a good candidate material for barrierless Si metallization and/or flip-chip solder bump application, with a low consumption rate comparable to that of Ni.