Search

In this study, a process for wet metallization on glass substrate involving adhesive electroless plating (ELP) is developed by integrating two material innovations. The first involves functionalizing a polymer-capped Pd nanocluster with amino silane compound to strengthen the adhesion between the ELP metal film and substrate. The second involves an additional nanoscaled TiO2 layer serving as the adhesion promoting layer (APL) coated on glass before metallization. After investigation with various tools, ELP metal film was observed to penetrate the mesoporous structure of TiO2 APL, reinforcing the adhesion of metallized film on glass through the mechanical anchoring effect. The formation of an interlayer between TiO2 APL and glass is not observed. A T-peel strength of 325 N m−1 is achieved. According to fracture analysis, the metal film/TiO2/glass structure breaks inside TiO2 APL, not TiO2 APL/glass, suggesting that further engineering developments are required to improve TiO2 APL coating.

In this study, we report a simple but efficient way to improve the thermal stability of a dye-sensitized solar cell by adding a small amount of commercial silica nano-powders in a non-volatile electrolyte system. The paste-like electrolyte not only shows better water repellence because of the hydrophobicity of silica powder but also allows film casting for replacing conventional injection process. Compared with the device using liquid type electrolyte or paste-like electrolyte using hydrophilic nano-powders, the device using hydrophobic paste shows superior thermal stability without costly sealing and extra encapsulation.

Plastic film is promising as a photoanode substrate of dye-sensitized solar cell (DSSC) for flexible applications, while a lowtemperature sintering process is generally adopted for the TiO2 mesoporous film due to unstable thermal property of general plastics. This study demonstrates that typical high-temperature TiO2 sintering can be adopted for preparing the photoanode when using a surface-metallized polyimide (PI) film. A Sn/Ni bi-layer is formed on a PI film via a chemical process as the conductive layer. The Sn/Ni-coated PI photoanode can withstand high-temperature TiO2 sintering at a peak temperature of 430 ◦ C for 30 min without significant visual deformation due to high thermal stability of PI and strength reinforcement caused by surface metallization. The DSSC employing the Sn/Ni-coated PI film as the photoanode substrate reaches an energy conversion efficiency of 3.44% under

In ultra-large scale integrated circuits (ULSIs), aluminum (Al) has been replaced by copper (Cu) as the interconnect material due to Cu has higher resistance to electromigration and lower electrical conductivity [1]. Unfortunately, Cu has high mobility in silicon (Si) and silicon dioxide (SiO2), thus impacting interconnect reliability and leading to inferior electrical performance or device failure. Therefore, it is necessary to form a good copper diffusion barrier between Si/SiO2 and Cu layer. In the past few decades, inorganic materials such as tantalum (Ta) or tantalum nitride (TaN) based compounds or metal-alloys has been successfully introduced as the diffusion barrier industrially. However, from the ULSI roadmap revealed by the International Technology Roadmap for Semiconductors report (ITRS), the necessary diffusion barrier thickness for the line-width of 22 nm is less than 2 nm [2], which challenges the current Ta or TaN technology by using the conventional vapor-phase deposition. Recently, a few reports use the organo-silane compounds such as 3-aminopropyltrimethoxysilane (APTMS) as the diffusion barrier to substitute inorganic Ta or TaN barrier layer [3-5], and show promising result. However, forming SAM is known to very sensitive to process conditions, particularly when SAM is prepared by wet-soaking. Imperfect SAM cannot block Cu diffusion efficiently and thus fails to compete with inorganic counterparts. In this study, we developed an all-wet, self-healing process to converge the copper diffusion blocking property on a Cu/SAM/SiO2 substrate. In particular, a 3-[2-(2-aminoethylamino)ethylamino] propyl-trimethoxysilane (ETAS) layer was deposited on SiO2 surface via wet soaking process. Then a 200 nm Cu film was electroless plated onto ETAS-treated SiO2 with the help of a home-made poly(vinyl alcohol)-capped palladium (PVA-Pd) nanoparticle catalysts. By varying ETAS soaking time and the ratio of PVA:Pd in the process, the sheet resistance of the Cu/SAM/SiO2 substrate after rapid thermal annealing (RTA) was investigated. As shown in Fig.1, it can be seen the sheet resistance increased rapidly after RTA over 300 oC in the case of no ETAS treatment, indicating the formation of copper silicide because of the absence of diffusion barrier layer. It is also found in the case of 30 minutes ETAS treatment (approaching SAM[6]) and 1:1 PVA to Pd ratio (ETAS-30-1xPVA-Pd), no copper silicide formation up to 500 oC. Interestingly, in 1 minute ETAS (ETAS-1) soaking samples, which is considered islandish ETAS coating rather than SAM, the PVA:Pd ratio affects the effectiveness of Cu diffusion barrier significantly. The more the PVA, the better Cu diffusion blocking capability is. Finally, in the sample processed by 1 minute islandish ETAS treatment and PVA:Pd ratio of 2 (ETAS-1-2xPVA-Pd), the Cu diffusion blocking capability is identical to the case of ETAS SAM, evidencing PVA can mend the imperfect SAM layer and thus converging the overall performance. Our study provides a simple and controllable process to utilize organic compound as the alternative for Ta or TaN diffusion barrier layer in fine line ULSI fabrication. REFERENCES [1] S. P. Murarka, Mater. Sci. Eng., 19 (1997) 87. [2] International Technology Roadmap for Semiconductors,2013 edition. [3] A. M. Caro, S. Armini, O. Richard, G. Maes, G. Borghs, C. M. Whelan and Y. Travaly, Adv. Funct. Mater., 20 (2010) 1125. [4] W. K. Han, G. H. Hwang, S. J. Hong, C. S. Yoon, J. S. Park, J. K. Cho and S. G. Kang, Appl. Surf. Sci., 255 (2009) 6082. [5] Y. Chung, S. Lee, C. Mahata, J. Seo, S. M. Lim, M. S. Jeong, H. Jung, Y. C. Joo, Y. B. Park, H. Kimd and T. Lee, RSC Adv., 4 (2014) 60123. [6] C. W. Hsu, W. Y. Wang, K. T. Wang, H. A. Chen and T. C. Wei, Sci. Rep., 7 (2017) 1. Figure 1

The trend in selective metallization for printed circuit board (PCB) is to replace lithography process because of its process complication and cost waste. Nowadays, there are many ways to selective metal deposition, like ink-jet technique or laser irradiation for electroless metal deposition. In this study, we develop an unique, novel method to realize selective electroless metal deposition by controlling surface hydrophilicity without the need of tedious photomask process. This technique is demonstrated by forming a superhydrophobic surface in the first step, and then laser patterning to allow bottom surface exposed. Those exposed surface was then metallized by a process involving “silane compound modification + nano-Palladium catalyst activation”. In particular, TiO2 nanoparticles is coated by spin-coating on the glass substrate. Then, the surface with TiO2 nanoparticles is modified by Perfluorooctyltriethoxysilane (PFOTES) in order to form a superhydrophobic surface. The water contact angle of the surface exceeds 150 degree at this stage. The superhydrophobic layer acts like a shelter that could prevent electroless plating reaction from the substrate surface. After that, laser beam is applied on the superhydrophobic surface to remove PFOTES/TiO2 so that the specific pattern is exposed. Finally, selective metallization is accomplished on the exposed surface using home-made Pd nanoparticles and commercial electroless metal solution. Figure 1

Compact layer (CL) with pinhole-free and excellent electron conductivity is critical in high-efficient scaffold-type perovskite solar cells. In this study, we thoroughly investigated electrodeposited TiOX (ED-TiOX) on FTO glass from aqueous TiCl3 solution including the kinetics of the electrodeposition, film morphology, optical and electronic properties. Furthermore, by controlling the total charge amount, the thickness of ED-TiOX films as well as device performance are tunable. When applying this method to fabricate the CL for scaffold-type perovskite solar cells, we compared the hole blocking effectiveness, charge extraction capability and photovoltaic performance of TiO2 CLs made by electrodeposition and other common methods such as dip coating (DC), spin coating (SC) and spray pyrolysis (SP). Current results reveal ED-TiOX CL performs best for its full coverage, thinnest thickness and mossy surface, rendering high shunt resistance and low ohmic resistance. In addition, our results also confirm in scaffold-type perovskite solar cell configuration, CL still provides charge extraction function in addition to the mesoporous scaffold. The device using ED-TiOX CL currently shows highest power conversion efficiency (PCE) up to 15.48%. Figure 1

In semiconductor manufacturer and IC package, electroless deposition (ELD) of nickel/phosphorous (Ni/P) film is a special promising skill [1]. In general, the core of ELD is a catalytic reaction that needs a trace amount of noble metal such as palladium as the activator to lower the activation energy of metal formation [2]. Because the adhesion of ELD Ni/P film relates to the interfacial characteristic of catalyst and silicon surface. In order to enhance the bridging between the silicon substrate and palladium (Pd) catalyst, modifying silicon surface with organo-silane compound such as 3-[2-(2-aminoethylamino)ethylamino] propyl-trimethoxysilane (ETAS) is commonly used. The ETAS treatment then forms a self-assembled monolayer (SAM) which is capable to interact with polymer-capped Pd catalyst and thereby promotes the adsorption of ELD Ni/P film [3]. However, it is known that the SAM formation is very sensitive to process condition such as soaking time and solvent agents. In this study, various ETAS modification on silicon wafer are investigated. In particular, the ETAS-modified film was done by a wet-soaking method in which the influence of soaking time and solvent agents onto silicon surface were discussed. As shown in Fig 1, the AFM images with various solvent agents of ETAS-modified surface showed significant difference which indicates that the solvent agents does influence SAM formation. The correlation on the solvent effect and the adhesion of ELD Ni/P on ETAS-modified silicon surface are discussed. REFERENCES [1] A. Brenner, G.E. Riddell, J. Res. Nat'l Bur. Std. 37 (1946) 31. [2] L. Li, B. Liu, Mater. Chem. Phys. 128 (2011) 303. [3] T. C. Wei, T. P. Pan, C. M. Chen, K. C. Lai, C. H. Wu, Electrochem. Commun. 54 (2015) 6 Figure 1

We previously reported a novel polyvinyl alcohol-capped palladium colloids (PVA-Pd) as the catalyst for the electroless plating of nickel-phosphorous (ELP-Ni-P) film on 3-2-(2-aminoethylamino) ethylamino propyl trimethoxysilane (ETAS)-modified Si surface [1]. It was found the interaction between PVA-Pd and amino-moiety on ETAS is the root cause of the superior adhesion of ELP-Ni-P film without the need of post annealing. The adhesion of ELP-Ni-P film catalyzed by PVA-Pd on ETAS-modified Si surface is significantly improved from 4.63 MPa to 10.83MPa when compared with it made via traditional Sn/Pd process. In this study, the effect of process parameters in this method including annealing temperature, annealing time, ETAS dipping time, PVA-Pd concentration and PVA-Pd dipping time are systematically investigated by means of design of experiments (DOE). From the analysis of variance (ANOVA) table, it is found the annealing temperature, annealing time and ETAS-dipping time have main effects on the adhesion of ELP-Ni-P film. Surprisingly, SEM cross-sectional image of the ELP-Ni-P film made by this method reveals that imperfect self-assembly monolayer (SAM) formation of ETAS aids the formation of nickel-silicide intermetallic (IMC) layer, rendering an even better adhesion before annealing. On the contrary, the adhesion of ELP-Ni-P film deposited on perfect ETAS monolayer becomes worse after post annealing. We speculate that silane-compound may play as a barrier layer for the IMC formation, which may jeopardize the original function of Ni-P film as the barrier layer for the subsequent copper layer in semiconductor industry. Reference: [1] T.-C. Wei, T.-C. Pan, C.-M. Chen, K.-C. Lai, and C.-H. Wu, "Annealing-free adhesive electroless deposition of a nickel/phosphorous layer on a silane-compound-modified Si wafer," Electrochemistry Communications, vol. 54, pp. 6-9, 2015. Figure 1

Eletroless deposition of nickel/phosphorus (Ni/P) film is a very promising skill for preparing diffusing barrier layer on silicon wafer. In general, palladium metal is needed as the catalyst to initiate electroless Ni/P deposition. In this study, we synthesized two types of palladium nanoparticles which is capped by polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA), coded as PVP-Pd & PVA-Pd, as the catalysts of electroless deposition. In order to enhance the adsorption of PVP-Pd or PVA-Pd on silicon surface, we apply 3- 2-(2-aminoethylamino)ethylamino propyl trimethoxysilane (ETAS) as a coupling agent to modify silicon surface then followed by electroless Ni/P deposition. Evidenced by transmission electron microscopy and scanning electron microscopy, PVP-Pd reveals slightly aggregated, while the particle shape of PVA-Pd is clearly defined; this makes a better distribution when PVA-Pd nanoparticles are adsorbed on silicon surface so that the adhesion of catalyst as well as Ni/P film is further improved. Finally, the interaction between ETAS and PVA-Pd were further explained by X-ray photoelectron spectroscopy. Compared with the adhesion of Ni/P layer catalyzed by commercial Sn/Pd colloids on unmodified silicon surface, the adhesion of Ni/P layer catalyzed by PVP-Pd or PVA-Pd on the ETAS modified silicon surface improved significantly by 2~3 times without the need of post-annealing treatment.

Electroless deposition (ELD) of nickel/phosphorous (Ni/P) layer has been a special interest in modern technique, especially in the production of diffusion barriers in the silicon industry [1]. The crucial part of ELD is a catalytic reaction that needs a trace amount of palladium [2] as the activator to lower the activation energy of metal formation. Due to the adhesion of ELD Ni/P film is associated with the interfacial property of catalyst and silicon surface. In order to increase the bridging between the silicon substrate and palladium catalyst, modifying silicon surface with organo-silane compound such as 3-[2-(2-aminoethylamino)ethylamino] propyl-trimethoxysilane (ETAS). The ETAS then form a self-assembled monolayer (SAM) to facilitate the adsorption of palladium catalyst [3]. However, it is known that the SAM formation is very sensitive to process condition such as soaking time, soaking temperature and solvent agents. In this study, the ETAS modification condition on silicon wafer is investigated. In particular, the ETAS-modified film was fabricated by a wet-soaking method and the effects of soaking time, soaking temperature and solvent agents onto silicon surface were discussed. As shown in Fig 1, the images of AFM with various soaking time of ETAS-modified silicon surface showed significant difference; this means that the long soaking time did influence SAM formation. Finally, the adhesion of ELD Ni/P on ETAS-modified silicon surface with different process parameters is discussed. REFERENCES [1] A. Brenner, G.E. Riddell, J. Res. Nat'l Bur. Std. 37 (1946) 31. [2] L. Li, B. Liu, Mater. Chem. Phys. 128 (2011) 303. [3] T. C. Wei, T. P. Pan, C. M. Chen, K. C. Lai, C. H. Wu, Electrochem. Commun. 54 (2015) 6 Figure 1

not Available.

not Available.

not Available.

not Available.

not Available.

not Available.

not Available.

not Available.

In this study, a cost-effective and low temperature wet process has been developed for the fabrication of a Pt counter electrode in dye-sensitized solar cells (DSSCs) with superior coating selectivity by means of self-assembly monolayer modification and electroless deposition. Using such Pt counter electrode prepared by our method, it is easy to deposit a Pt thin film under ambient atmosphere and low temperature without a high vacuum chamber and the acceptable charge-transfer resistance of 1.24 Ω cm 2 is obtained. Moreover, the DSSC exhibited improved performance compared to the DSSC with a sputtered Pt counter electrode.

not Available.