Yu-Hsien Chou

A method to fabricate field emitters using electroless codeposited composite of MWNTs and nickel

A method to fabricate good carbon nanotube (CNT) field emitters using electroless codeposition and CNT purification techniques was developed. Multiwalled CNTs (MWNTs) were codeposited with Ni to form a composite layer acting as the emitter. This composite layer is uniform in thickness and the MWNTs distributed in Ni matrix show a strong adhesion to the substrate. To ensure the emitting quality and good dispersion of MWNTs in the composite, heat annealing and acid immersion process were employed. The composite film shows good emission uniformity and the current density of 1.0 mA/cm 2 was obtained at about 5.7 V/μm.

Effects of Molybdate Concentration on the Characteristics of Ni – Mo – P Diffusion Barriers Grown by Nonisothermal Electroless Deposition

Ternary Ni-based amorphous films can serve as a barrier layer for Cu interconnects in ultralarge-scale integration (ULSI) applications. In this paper, Ni-Mo-P films deposited on silicon wafers without a complicated pretreatment such as Pd activation were prepared using a nonisothermal deposition (NITD) method. The deposition solutions and operating conditions for preparing the Ni-Mo-P alloys are presented, and the effect of the concentration of MoO 2- 4 added in electrolytes on the deposition rate is investigated. The surface morphology, microstructures, compositions, and electrical resistivity of the Ni-Mo-P deposits are also thoroughly examined. Based on the experimental results, the Ni-based ternary alloys produced by the NITD method contain high levels of both Mo and P, and the properties of Ni-Mo-P films are dependent on the concentration of molybdate in electrolytes. It is concluded that the Ni-Mo-P thin films produced by the proposed approach in this study are promising for the 60 nm technologies in ULSI.

Defect-Free Copper Filling Using Nonisothermal Electroless Deposition with Fluorocarbon Surfactant

Electroless copper bottom-up filling of patterned substrates using nonisothermal deposition (NITD) with the addition of adequate surfactant was demonstrated. Combining the inhibitive ability of adequate surfactant with the higher driving force of NITD method, superfill of vias or trenches using only one inhibitor in the copper damascene of integrated circuits (ICs) was achieved. We tested several commercial surfactant agents and found that fluorinated alkyl quaternary ammonium iodides (FC) is best compatible to our NITD method. Void-free copper-filled features can be obtained by introducing the surfactant FC into the electroless bath of NITD. Furthermore, using our method, the conductivity of copper film was not negatively affected. We conclude that the surfactant FC combined with NITD method is very promising for the applications in filling trenches and vias with copper films in the IC industry.

The Structure and Properties of Electroless Ni-P and Ni-Mo-P Deposits

The structure and properties of electroless Ni-P and Ni-Mo-P alloys, including the as-plated and annealed deposits, on the aluminum alloy 5052, have been investigated to evaluate the corrosion resistance, thermal stability, electric conductivity, and mechanical characteristics of the coating assemblies. The corrosion behavior of the obtained deposits was examined in a 0.5M H2SO4 environment. The crystal structure of the electroless Ni-based alloys was analyzed by X-ray diffraction (XRD), and the surface morphology and microstructure of Ni-P and Ni-Mo-P alloys were examined by field emission scanning electron microscopy (FE-SEM). The experimental results indicate that the corrosion rate of the Ni-Mo-P coating produced at 70°C and pH 7.0 is almost equals that of the Ni-P film in a 0.5M H2SO4 environment. It is also found that the Ni-Mo-P ternary alloy reveal excellent thermal stability after annealing at 400°C for 1 hr. The electroless Ni-Mo-P deposits have a potential to apply to precision mould and surface metallization of substrates, based on the excellent performance of the ternary alloys.

The in-situ Annealing of Electroless Deposited Copper Films Using NITD Method for ULSI

In this paper we demonstrate the feasibility of direct electroless plating of copper in the NITD system with in-situ annealing treatment. As a result of the high temperature effect during deposition, the peak ratio of Cu (111 )/Cu (200) of copper film reached 19. The resistivity of as-deposited Cu layer was as low as 2.45 muOmega-cm. The NTID system, using single step to deposit metal film, has several advantages that can discard the post-annealing and simplify the deposition processes. It has potential for the application on ULSI.