Rapid Spray Method for Improving Cu-Epoxy Interface Strength

2010 ◽  
Author(s):  
Robert C. Wetherhold ◽  
Elena Pisanova ◽  
Hani Alarifi
Keyword(s):  
Aqueous Solution ◽  
Copper Foil ◽  
Surface Coverage ◽  
Peel Strength ◽  
Copper Surface ◽  
Interface Strength ◽  
Range Effect ◽  
Trade Off ◽  
Copper Surfaces ◽  
Spray Method

A simple spray method using a plain orifice atomizer has been developed for depositing γ-aminopropyltriethoxysilane (APS) from solutions in water and in methanol onto copper surfaces. The peel strengths between copper foil and epoxy resin were measured with and without APS deposition. In all cases, a higher concentration of APS gives higher peel strength. APS applied from 1 wt% solution in methanol resulted in higher peel strength than when applied from a 1 wt% aqueous solution; the opposite was true with 0.2 wt% APS solutions, indicating a trade-off between deposited APS film thickness and surface coverage. APS was very effective when chemisorption occurred at the surface but much less effective when there was only physisorption. A study of the fracture surfaces showed that the failure is cohesive, inside the epoxy layer, and that the deposited APS on the copper surfaces had a long-range effect which was seen deep in the epoxy layer, well away from the copper surface.

scholarly journals The mechanism of catalytic decomposition

1925 ◽  
Vol 108 (746) ◽  
pp. 355-378 ◽  
Keyword(s):  
Copper Foil ◽  
Active Agent ◽  
Catalytic Decomposition ◽  
Hydrocarbon Chain ◽  
Copper Surface ◽  
Catalytic Action ◽  
Hydroxyl Group ◽  
Copper Surfaces ◽  
X Ray ◽  
Molecular Attraction

In recent years a large amount of evidence has accumulated showing that the range of molecular attraction is very small; hence the specific catalytic action of each substance must decrease very fast as the distance of the reacting molecules from the surface increases. The catalytic action must therefore be confined to the surface layer of adsorbed molecules alone. When alcoholic substances react at copper surfaces below 280° C., only the — CH 2 OH group is changed. The only molecules which react, therefore, are those which have the — CH 2 OH group in contact with the copper. The behaviour of cetyl alcohol on water, and on glass and steel, shows that the hydroxyl group is the active agent in orientating the film structure.It is known also that alcohol will displace hydrocarbons from copper foil. The polar hydroxyl group is attracted to the copper surface more strongly than is the hydrocarbon chain. The evidence, therefore, shows that not only are the molecules that react adsorbed with the hydroxyl group in contact with the surface, but that the whole layer in contact with the catalyst is orientated in this manner. It may be that the molecules in the successive layers are also arranged similarly, but the evidence is scanty. In the case of the fatty acids, X-ray analysis gives confirmation of this arrangement

Discrimination of Surface Textures Using Fractal Methods

1994 ◽  
Vol 367 ◽  
Author(s):  
Jill P. Card ◽  
J. M. Hyde ◽  
T. Giversen
Keyword(s):  
Fractal Analysis ◽  
Copper Foil ◽  
Copper Surface ◽  
Electronic Packages ◽  
Confidence Limits ◽  
Lead Frame ◽  
Copper Surfaces ◽  
Surface Textures ◽  
Fractal Approach ◽  
Copper Lead

AbstractThis paper investigates the use of fractal metrics for discrimination of copper surface textures. Measurements of copper surfaces, using contacting profilometry, provided the raw data for the fractal analysis. The samples tested included copper foil samples and a copper lead frame, typical of those in use in plastic electronic packages. The fractal Hausdorf dimension and upper/lower ranges of fractal scale are analyzed by the coastline method and compared using Bonferroni multiple confidence limits. Metrics show significant differences between sample couplets, indicating significant precision in the fractal approach to adequately quantify surface texture qualities.

scholarly journals The passive state and adhesion

1930 ◽  
Vol 126 (803) ◽  
pp. 630-631 ◽  
Keyword(s):  
Aqueous Solution ◽  
Copper Surface ◽  
Copper Plate ◽  
Passive State ◽  
Metallic Surfaces ◽  
Absolute Alcohol ◽  
Surface Layers ◽  
Copper Surfaces ◽  
Chemical Substances ◽  
Magnesia Powder

In the course of an investigation into the tensile strength of joints formed by thin films of pure chemical substances between surfaces of steel or copper (‘Roy. Soc. Proc.,’ A, vol. 118, p. 209 (1928)), a curious effect due to the production of passivity at a copper surface was noticed. In making such measurements it is, of course, essential that the metallic surfaces should be absolutely clean and dry. Owing to the ease with which copper surfaces acquire a tarnish film, their cleaning presented some difficulty. On one occasion the copper plate was boiled in absolute alcohol and plunged, whilst still hot, into water containing a few drops of concentrated nitric acid, in order that it might cool in a non-tarnishing medium. When taken out, the surface was found to have assumed a uniform dull reddish tint quite unlike the patchy appearance produced by the usual visible tarnish film. This appearance persisted when the plate was boiled in alcohol or water and cooled in air and also when it was left exposed to impure damp air for several hours, i. e. , it survived conditions under which a normal copper surface would have tarnished rapidly. Gentle polishing with very finely divided magnesia powder on silk did not remove the reddish-tint, although abrasion with fine emerypaper, by removing the upper surface layers did. Normality was most conveniently restored by boiling the plate in a 2-5 per cent. aqueous solution of ammonia when the surface tarnished and blackened in patches; this tarnish was removed by polishing with magnesia powder on a wet leather and the process repeated until the surface tarnished uniformly. The surface of the plate, after removal of this tarnish, was found to be normal.

The microstructure of functionalized poLyacrylonitrile beads for bioseparations

1990 ◽  
Vol 48 (4) ◽  
pp. 1094-1095
Author(s):  
Eduardo A. Kamenetzky ◽  
David A. Ley
Keyword(s):  
Aqueous Solution ◽  
Affinity Chromatography ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Surface Coverage ◽  
Vacuum Impregnation ◽  
Thin Sections ◽  
Selective Staining ◽  
Low Viscosity ◽  
Diamond Knife

The microstructure of polyacrylonitrile (PAN) beads for affinity chromatography bioseparations was studied by TEM of stained ultramicrotomed thin-sections. Microstructural aspects such as overall pore size distribution, the distribution of pores within the beads, and surface coverage of functionalized beads affect performance properties. Stereological methods are used to quantify the internal structure of these chromatographic supports. Details of the process for making the PAN beads are given elsewhere. TEM specimens were obtained by vacuum impregnation with a low-viscosity epoxy and sectioning with a diamond knife. The beads can be observed unstained. However, different surface functionalities can be made evident by selective staining. Amide surface coverage was studied by staining in vapor of a 0.5.% RuO4 aqueous solution for 1 h. RuO4 does not stain PAN but stains, amongst many others, polymers containing an amide moiety.

Cu-Direct Laser Drilling of Blind Via-Hole in Multi-Layer PWBs: Influence of Surface Treatment on Drilled Hole Quality

2009 ◽  
Author(s):  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa ◽  
Tsukasa Ayuzawa
Keyword(s):  
Surface Treatment ◽  
Co2 Laser ◽  
Copper Foil ◽  
Laser Energy ◽  
Copper Surface ◽  
Laser Drilling ◽  
Hole Quality ◽  
Direct Laser ◽  
Overhang Length ◽  
Direct Drilling

This report describes the quality assessment of Blind Via Holes (BVHs) of Printed Wiring Boards (PWBs) drilled by a CO2 laser using Cu-direct drilling. In the Cu-direct drilling method, the copper foil and the build-up layer are melted at the same time, and the surface is treated to increase the laser energy absorbed by the copper foil since an untreated copper surface reflects most of the 10.6-μm-wavelength CO2 laser beam. However, there are few reports dealing with Cu-direct laser drilling of PWBs. In addition, when copper and resin with different processing thresholds are drilled at the same time, occurrences of a defect called overhang have been observed. So, in this report, first we propose a new method using thermography to measure the absorptance of a PWB surface for a CO2 laser. Moreover, we investigate how surface treatment of the outer copper foil influences the quality of a laser-drilled hole. Then, we observe the circumference of a point irradiated with the CO2 laser and explain how melting processes are different from surface treatment. Finally, based on the research we establish a method in order to cut down the overhang length as a parameter of drilled-hole quality. We also show that a high absorptance improves BVH quality.

scholarly journals Usage of Sims and Auger Test Methods in the Production of Multilayer Printed Circuit Boards

1984 ◽  
Vol 11 (3) ◽  
pp. 225-229
Author(s):  
E. Toth ◽  
P. Banlaki ◽  
I. Hajdu ◽  
J. Pinkola
Keyword(s):  
Copper Foil ◽  
Printed Circuit Boards ◽  
Copper Surface ◽  
Test Methods ◽  
Main Constituent ◽  
Circuit Boards ◽  
Adhesion Properties ◽  
Printed Circuit ◽  
Quality And Reliability ◽  
Type Electrolyte

The quality and reliability of multilayer boards are determined by the adhesion strength between the copper sheets and the epoxy-glass laminates. The adhesion properties of copper foil may be improved by mechanical or chemical roughening. The most efficient method is, however, to oxidize the copper surface.Oxidized copper layers have been tested by thermogravimetry. Subsequently the oxide layers have been tested by Auger and SIMS techniques. The results showed that the main constituent of the oxide layer produced in a sodium hypochlorite type electrolyte is Cu20.

Pool Boiling Heat Transfer of Water on Hydrophilic Surfaces With Different Wettability

2016 ◽  
Author(s):  
Adam R. Girard ◽  
Jinsub Kim ◽  
Seung M. You
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Copper Surface ◽  
Contact Angles ◽  
Copper Surfaces ◽  
Nanoscale Structures ◽  
Flat Surfaces ◽  
Hydrophilic Surfaces ◽  
Alkali Solutions

The effect of wettability on boiling heat transfer (BHT) coefficient and critical heat flux (CHF) in pool boiling of water on hydrophilic surfaces having different contact angles was investigated. Hot alkali solutions were utilized to promote cupric and cuprous oxide growth which exhibited micro and nanoscale structures on copper surfaces, with thicknesses on the order of a couple of micrometers. These structure and surface energy variations result in different levels of wettability and roughness while maintaining the effusivity of the bare copper surface. The study showed that the BHT coefficient has an inverse relationship to wettability; the BHT coefficient decreases as wettability increases. Furthermore, it was shown that this dependency between BHT coefficient and wettability is more significant than the relationship between BHT coefficient and surface roughness. The CHF was also found to increase with increases in wettability and roughness. For the most hydrophilic surface tested in this study, CHF values were recorded near the 2,000 kW/m2 mark. This value is compared with maximum values reported in literature for water on non-structured flat surfaces without area enhancements. Based on these results it is postulated that there exists a true hydrodynamic CHF limit for pool boiling with water on flat surfaces, very near 2,000 kW/m2, independent of heater material, representing an 80% increase in the limit suggested by Zuber [1].

Studies of Copper Surfaces modified by Thermal and Plasma Treatments

2000 ◽  
Vol 612 ◽  
Author(s):  
G.P. Beyer ◽  
M. Baklanov ◽  
T. Conard ◽  
K. Maex
Keyword(s):  
Chemical Composition ◽  
Thermal Treatment ◽  
Photoelectron Spectroscopy ◽  
Hydrogen Plasma ◽  
Copper Film ◽  
Copper Surface ◽  
Ex Situ ◽  
Clean Room ◽  
Copper Surfaces ◽  
The Difference

AbstractIt was found that copper surfaces, which had been exposed to a clean room atmosphere, were covered by a layer, whose chemical composition can be described by Cu(OH)2·CuCO3. This layer can effectively be removed by either a short thermal treatment in vacuum at 350°C, a hydrogen plasma treatment, or a combination of both. Ex-situ photoelectron spectroscopy measurements show little difference of the chemical composition of the surface after the respective treatments. The thermal treatment, however, gives rise to re-crystallisation of the copper film due to the difference in temperature of deposition and the anneal. Ex-situ ellipsometry measurements indicate that the hydrogen plasma not only removes Cu(OH)2·CuCO3 but also passivates the copper surface.

Preparation and Properties of Thermoplastic Polyamide-imide and Polyurea-amide-imide/Copper Foil Composites

2005 ◽  
Vol 13 (8) ◽  
pp. 777-794 ◽  
Author(s):  
Meng-Shun Huang ◽  
Ming-Chien Yang ◽  
Shen Chou
Keyword(s):  
Copper Foil ◽  
Chemical Resistance ◽  
Dissipation Factor ◽  
Peel Strength ◽  
Hot Press ◽  
Adhesive Properties ◽  
H Nmr ◽  
Chemical Structures ◽  
Tetracarboxylic Dianhydride ◽  
Strength Retention

Polyamide-imide (PAI) and polyurea-amide-imide (PUAI) resins were polymerized from five reactants: 4,4'-oxydianiline, 4-nitrobenzoyl chloride, 4,4'-diphenylmethane diisocyanate, 1,2,4,5-benzenetetracarboxylic dianhydride, and 3,3'-4,4'-benzophenone tetracarboxylic dianhydride. Their chemical structures were characterized using elemental analysis, FTIR and 1H NMR spectroscopy. Their thermal properties, adhesive properties, electrical properties, heat resistance, and chemical resistance were studied. The experimental results show that the glass transition temperatures of PAI and PUAI films occurred respectively at 360 °C and 229 °C, and the 10% weight loss occurred respectively at approximately 481 °C and 420 °C. The optimal hot-press conditions for PAI/copper foil (CU) composite were 380°C and 4.90 MPa, whereas those for PUAI/copper foil (CU) composites were 250 °C and 4.90 MPa. Values of the peel strength, dielectric constant, and dissipation factor were obtained and the peel strength was re-measured after a thermal stability test. The chemical resistance tests showed that the peel strength retention values of the PAI/CU and PUAI/CU composites were respectively more than 95% and more than 94% after immersing in 10% H2SO4 solution at 70 °C for 1 h.

Enabling Low Temperature Copper Bonding with an Organic Monolayer

2009 ◽  
Vol 74 ◽  
pp. 133-136 ◽  
Author(s):  
Ang Xiao Fang ◽  
Jun Wei ◽  
Chen Zhong ◽  
Wong Chee Cheong
Keyword(s):  
Bonding Temperature ◽  
Copper Surface ◽  
Mems Devices ◽  
Ambient Conditions ◽  
Copper Surfaces ◽  
Organic Monolayer ◽  
Metallurgical Bonding ◽  
Alternative Approach ◽  
Copper Material ◽  
Joint Integrity

Typically, copper material is used as a bonding material in MEMs devices for its excellent mechanical, electrical and hermetic properties. Direct copper bonding, however, requires high temperature (>300°C) to forge a bond due to the oxidative nature of copper. In this study, using an alternative approach based on an organic monolayer coating, we demonstrate metallurgical bonding between two copper surfaces under ambient condition at low bonding temperature below 140°C, while maintaining reliable mechanical joint integrity of 50MPa. This monolayer is believed to behave as a passivation layer, protecting the copper surface against oxidation under ambient conditions. In contrast to a bulk oxide layer, this layer can be easily displaced during mechanical deformation at the bonding interface.

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