• Journal of the Korean institute of surface engineering
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• v.37 no.6
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• pp.335-343
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• 2004

Bath stabilizers in the electroless nickel(EN) plating solution are known to prevent sudden bath decomposition and extend its lifetime. Further, every stabilizer has a different role and function in EN solution and it influences the surface structure. In this study, the effects of various stabilizers on the deposition rate, surface morphology, deposition content of phosphor and hardness were investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.621-624
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• 1999

Metalization technology of the fine patterns by electroless plating is required in place of electrodeposition as high-density printed boards(PCR) become indispensable with the miniaturization of electronic components. Electroless nickel plating is a suitable diffusion barrier between conductor meta1s, such as Al and Cu and solder is essetional in electronic packaging in order to sustain a long period of service. Moreover, Electroless nickel has particular characteristics including non-magnetic property, amorphous structure. wear resistance, corrosion protection and thermal stability In this study fundamental aspects of electroless nickel deposition were studied with effort of complexeing agents of different kinds. Then the property of electroless deposit are controlled by the composition of the deposition solution the deposition condition such as temperature and pH value and so on. the characteristics of the deposits has been carried out.

• Journal of the Korean institute of surface engineering
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• v.47 no.5
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• pp.269-274
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• 2014

Electroless plating process as a solution deposition method is a viable means of preparing conductive metal films on non-conducting substrates through chemical reactions. In the present study, the preparation and properties of electroless Ni-plating on flexible silicone rubber are described. The process has been performed using a conventional Ni(P) chemical bath. Additives and complexing agents such as ammonium chloride and glycine were added and the reaction pH was controlled by NaOH aqueous solution. Ni deposition rate and crystallinity have been found to vary with pH and temperature of the plating bath. It was shown that Ni-films having the high crystallinity, enhanced adhesion and optimum electric conductivity were formed uniformly on silicone rubber substrates under pH 7 at $70^{\circ}C$. The conductive Ni-plated silicone rubber showed a high electromagnetic interference shielding effect in the 400 MHz-1 GHz range.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.53-57
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• 2004

In this paper, we will present the Aspheric Surface Program for optical element. X-ray optical element designed to give a high resolution and reflectively in order to observe the living cell in the range of the water window. According to optical design, we developed the Aspheric Surface Program using the visual basic. Using the Aspheric Surface Program, we directly machined the electroless nickel bulk.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.29.2-29.2
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1507-1510
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• 2005

This study was carried out as a part of the research on the development of a maskless and electroless process for fabricating metal micro/nanostructures by using a nanoindenter and an electroless deposition technique. $2-\mu{m}-deep$ indentation tests on Ni and Cu samples were performed. The elastic recovery of the Ni and Cu was 9.30% and 9.53% of the maximum penetration depth, respectively. The hardness and the elastic modulus were 1.56 GPa and 120 GPa for Ni and 1.49 GPa and 100 GPa for Cu. The effect of single-point diamond machining conditions such as the Berkovich tip orientation (0, 45, and $90^{\circ}$) and the normal load (0.1, 0.3, 0.5, 1, 3, and 5 mN), on both the deformation behavior and the morphology of cutting traces (such as width and depth) was investigated by constant-load scratch tests. The tip orientation had a significant influence on the coefficient of friction, which varied from 0.52-0.66 for Ni and from 0.46-0.61 for Cu. The crisscross-pattern sample showed that the tip orientation strongly affects the surface quality of the machined area during scratching. A selective deposition of Cu at the pit-like defect on a p-type Si(111) surface was also investigated. Preferential deposition of the Cu occurred at the surface defect sites of silicon wafers, indicating that those defect sites act as active sites for the deposition reaction. The shape of the Cu-deposited area was almost the same as that of the residual stress field.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.5
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• pp.193-198
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• 2015

In the study, electroless Ni-plating on flexible ethylene-propylene-diene-monomer (EPDM) rubber sheets for the application of an insert block for shielding electromagnetic interference of multi cable transit (MCT) systems was investigated. Ni crystallinity and adhesion have been found to vary with processing parameters such as pH and temperature of the plating bath. It was shown that Ni-films having the high crystallinity and optimum electric conductivity were obtained on EPDM rubber sheets under pH 7 and 8 at $60{\sim}70^{\circ}C$. The conductive Ni-plated EPDM rubber prepared at pH 7 at $70^{\circ}C$ showed the enhanced adhesion and electric conductivity, and the high electromagnetic interference shielding effect in the 400 MHz~1 GHz range.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.230-234
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• 2009

It is significant technique to increase competitiveness that solar cells have a high energy conversion efficiency and cost effectiveness. When making high efficiency crystalline Si solar cells, evaporated Ti/Pd/Ag contact system is widely used in order to reduce the electrical resistance of the contact fingers. However, the evaporation process is no applicable to mass production because high vacuum is needed. Furthermore, those metals are too expensive to be applied for terrestrial applications. Ni/Cu/Ag contact system of silicon solar cells offers a relatively inexpensive method of making electrical contact. Ni silicide formation is one of the indispensable techniques for Ni/Cu/Ag contact sytem. Ni was electroless plated on the front grid pattern, After Ni electroless plating, the cells were annealed by RTP(Rapid Thermal Process). Ni silicide(NiSi) has certain advantages over Ti silicide($TiSi_2$), lower temperature anneal, one step anneal, low resistivity, low silicon consumption, low film stress, absence of reaction between the annealing ambient. Ni/Cu/Ag metallization scheme is an important process in the direction of cost reduction for solar cells of high efficiency. In this article we shall report an investigation of rapid thermal silicidation of nickel on silngle crystalline silicon wafers in the annealing range of $350-390^{\circ}C$. The samples annealed at temperatures from 350 to $390^{\circ}C$ have been analyzed by SEM(Scanning Electron Microscopy).

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.41-46
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• 2005

A systematic investigation of shear testing was conducted to find a relationship between Ni-Sn intermetallic spatting and the brittle fracture observed in electroless Ni(P)/solder interconnection. Brittle fracture was found in the solder joints made of Sn-3.5Ag, while only ductile fracture was observed in a Cu-containing solder (Sn-3.0Ag-0.5Cu). For Sn-3.0Ag-0.5Cu joints, $(Ni,Cu)_3Sn_4$ and/or $(Cu,Ni)_6Sn_5$ compound were formed at the interface without spatting from the Ni(P) film. For Sn-3.5Ag, $Ni_3Sn_4$ compound was formed and brittle fracture occurred in solder pads where $Ni_3Sn_4$ had spalled. From the analysis of fractured surfaces, it was found that the brittle fracture occurs through the $Ni_3SnP$ layer formed between $Ni_3Sn_4$ intermetallic layer and the Ni(P) film. Since the $Ni_3SnP$ layer is getting thicker during/ after $Ni_3Sn_4$ spatting, suppression of $Ni_3Sn_4$ spatting is crucial to ensure the reliability of Ni(P)/solder system.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.83-87
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• 2001

A 110 mm diameter aspheric metal secondary mirror for a test model of an earth observation satellite camera was fabricated by ultra-precision single point diamond turning (SPDT). Aluminum alloy for mirror substrates is known to be easily machinable, but not polishable due to its ductility. A harder material, Ni, is usually electrolessly coated on an Al substrate to increase the surface hardness for optical polishing. Aspheric metal secondary mirror without a conventional polishing process, the surface roughness of Ra=10nm, and the form error of $Ra={\lambda}/12({\lambda}=632nm)$ has been required. The purpose of this research is to find the optimum machining conditions for reflector cutting of electroless-Ni coated Al alloy and apply the SPDT technique to the manufacturing of ultra precision optical components of metal aspheric reflector.