CVD Co film was investigated as an alternative barrier layer to the conventional PVD TaN\Ta in V1\M2 structure for 32nm node. We improved via filling performance and upstream (V1→M2) electromigration (EM) lifetime by more than three times. Excellent step coverage of CVD barrier makes it possible to reduce the thickness of the barrier metal by 30% and to increase the volume of Cu in metal lines. RC delay also reduced with decrease in resistance. Since adhesion at the interface between the barrier-Co and Cu also is strong, migration of Cu atoms is dramatically slowed down. EM in the via is finally deterred due to absence of pre-existing voids, consequently lifetime increases. This CVD Co process is expected to be beneficial for the next technology generation beyond 20nm node.

A formation process for copper bottom-up filling of submicrometer via holes and trenches using iodine as a catalytic surfactant and hexafluoroacetylacetonate-copper-vinyltrimethylsilane in catalyst-enhanced chemical vapor deposition of copper is presented. The film growth rate of copper at the bottom of the submicrometer features is continuously accelerated until the features are filled, and this results in the bottom-up filling of submicrometer features previously considered not viable in vacuum deposition techniques. The accelerated film growth appears to be due to the accumulation of the catalytic surfactant iodine on the surface of the copper films growing at the bottom of the submicrometer features believed to result from reduction of the sidewall area in the submicrometer features as the film grows. The newly developed technique for the copper bottom-up filling of submicrometer features will have a great impact on on-chip copper interconnects for the next generation of microelectronic devices. Moreover, this bottom-up growth mode in submicrometer features is expected to be universal to other systems of chemical vapor deposition in which a catalytic surfactant is used.

Ultrathin Cu seed layer was deposited by metallorganic chemical vapor deposition ͑MOCVD͒ on Ru layer using hexafluoroacetylacetonate copper vinyltrimethylsilane ͓͑hfac͒Cu I ͑vtms͔͒. On Ru, the incubation time for Cu MOCVD was nonexistent. As compared with MOCVD Cu on TaN, the nuclei density of Cu was considerably increased on Ru and the wetting angle of Cu on Ru was small ͑22°͒. Therefore, the coalescence between Cu islands on Ru layer begins earlier by prohibiting the severe threedimensional Cu growth that is generally observed on TaN layer. As a result, 10 nm thick continuous Cu film with 1.75 nm root-mean-squared surface roughness was easily prepared on 40 nm thick Ru at 150°C.Copper ͑Cu͒ interconnection has been used extensively in fabricating metal interconnections for large scale integrated circuits because of its favorable electrical conductivity ͑1.67 ⍀ cm͒ and superior resistance to electromigration. 1 The most widely used deposition method for Cu is electrochemical plating ͑ECP͒, which is capable of refilling dual-damascene structures in a fashion of bottom-up, so-called superfilling. In this ECP of Cu, a Cu seed layer is a prerequisite for an electrode, 2 and it should be prepared as thin as possible, having a continuous and smooth film surface, to achieve the Cu superfilling without leaving any voids on dual-damascene structures. 3,4 In forming the Cu seed layer, physical vapor deposition ͑PVD͒ methods are currently in wide use. However, as the aspect ratio of dual-damascene structures increases, the Cu seed layer formed by PVD begins to show practical disadvantages on its step coverage owing to the line-of-sight approach of PVD. As an alternative to overcoming this inherent demerit of PVD, metallorganic chemical vapor deposition ͑MOCVD͒ of Cu has been studied for several years because of its conformal deposition characteristics. 5,6 However, in MOCVD of Cu, the film growth on the Cu diffusion barrier metals, such as TiN, Ta, and TaN, generally follows a three-dimensional island growth mode, 7 and has a relatively long incubation time to form a continuous Cu film. Thus, the deposited Cu film normally has a severe surface roughness. 7 In addition, the Cu film formed by MOCVD does not adhere well to the diffusion barrier metals, showing an easy peeling-off during a post process as chemical mechanical polishing. 8,9 Recently, it has been reported that a 1-2 nm thick Ru film as an interlayer between MOCVD Cu and its diffusion barrier metals improves the adhesion property. 10 Furthermore, Ru itself is regarded as a promising candidate for a Cu diffusion barrier metal, because it is a noble transition metal with high melting point ͑2310°C͒, and has lower electrical resistivity ͑7.6 ⍀ cm͒ 11 than those of Ta and TaN, and is immiscible with Cu. 12 In this work, Cu MOCVD has been preformed on a Ru layer to investigate the film growth behaviors of MOCVD Cu. On Ru thin films, no incubation time is detected and three-dimensional island growth is also suppressed during the initial stage of the Cu film growth. As a...

A serpentine guard trace is proposed to reduce the peak far-end crosstalk voltage and the crosstalk induced timing jitter of parallel microstrip lines on printed circuit boards. The vertical sections of the serpentine guard increase the mutual capacitance without much changing the mutual inductance between the aggressor and victim lines. This reduces the difference between the capacitive and inductive couplings and hence the far-end crosstalk. Comparison with the no guard, the conventional guard, and the via-stitch guard shows that the serpentine guard gives the smallest values in both the peak far-end crosstalk voltage and the timing jitter. The time domain reflectometer (TDR) measurement shows that the peak far-end crosstalk voltage of serpentine guard is reduced to 44% of that of no guard. The eye diagram measurement of pseudo random binary sequence (PRBS) data shows that the timing jitter is also reduced to 40% of that of no guard.

Atopic dermatitis is known not to respond well to many clinical treatments. In this report, we present the case of an adult woman with atopic dermatitis who was effectively treated by using traditional Korean medicine (TKM). The patient was diagnosed with psoriasis based on lung dryness and heat and heart fire. The patient underwent acupuncture treatment based on the theory of Sa-Am acupuncture. Two meridians, the hand tai-yin meridian and the foot tai-yang meridian, were used to control lung dryness, lung heat, and heart fire. Using the LU9 and SP3 acupoints to tonify the hand tai-yin meridian, we could sedate lung dryness and heat, and using the BL67 acupoint to tonify the foot tai-yang bladder meridian, we could sedate heart fire. With this treatment, her symptoms completely disappeared in about 6 months. This case report provides a preliminary indication that TKM, especially Sa-Am acupuncture, can be effective for treating patients with psoriasis. Thus, further study is warranted.