Tae-Gyu Woo

Effects of plasma treatment on the peel strength of Ni on polyimide

In microelectronics packaging, the reliability of the metal/polymer interface is an important issue because the adhesion strength between dissimilar materials is often inherently poor. This paper reports the peel strength and surface morphology of a Cu/Ni/PI structure flexible copper clad laminate (FCCL) based on polyimide(PI) according to the pre-treatment atmosphere and times. Field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were used to analyze the surface morphology, crystal structure and interface binding structure, respectively, of the sputtered Ni, Cu, and electrodeposited copper foil layers. The surface roughness of the Ni and Cu sputtered deposition layers and the crystal structure of the electrodeposited Cu layer changed according to the pre-treatment atmosphere and times of PI. The PI surface etching speeds and surface shapes differed according to the gas used in plasma preprocessing. The highest peel strength (mean 15.8 gf/mm) can be obtained in a preprocessing process for 400 seconds in an O2 atmosphere due to the increase in mechanical binding force and change in chemical binding structure caused by the increase in polyimide surface roughness.

Effect of Electrolyte Compositions on the Physical Property and Surface Morphology of Copper Foil

This study examined the effect of copper and sulfuric acid concentrations on the surface morphology and physical properties of copper plated on a polyimide (PI) film. Electrochemical experiments with SEM and a four-point probe were performed to characterize the morphology and mechanical characteristics of copper electrodeposited in the composition of an electrolyte. The resistivity and peel strength were controlled using a range of electrolyte compositions. A lower resistivity and high flexibility were obtained when an electrolyte with 20 g/l of copper was used. However, a uniform surface was obtained when a high current density that exceeded 20 mA/cm was applied, which was maintained at copper concentrations exceeding 40 g/l. Increasing sulfuric acid to >150 g/l decreased the peel strength and flexibility. The lowest resistivity and fine adhesion were detected at a Cu: H2SO4 ratio of 50:100 g/l. (Received March 23, 2010)

The effect of additives and current density on mechanical properties of cathode metal for secondary battery

Electrolyte copper foils used as a cathode material in secondary cells require the mechanical characteristic of high elongation ratios. In this study the effects of additives, current densities, and concentrations of sulfuric acid used in electrolyte plating on the mechanical characteristics of copper foils are analyzed. In the case of additive A, no significant changes in tensile strength and crystal structure were observed, but the elongation ratio is reduced by 43% when 100 ppm of additive is added. For additive B, the elongation ratio is rapidly decreased even though the growing orientation of crystals becomes parallel to the faces of (111) and (220) from the face of (200). In the case of decreasing current densities or increasing concentrations of sulfuric acid, the elongation ratio is respectively increased by 74% and 54%, and the growing orientation of crystals is directed from (200) to (111). Also, for additive A at low current densities, the increase in crystal sizes differed from that of high current densities. This approach represents a possible method for additionally improving elongation ratios by properly controlling the amount of the additive A.

The Effect of Hydroxy Ethyl Cellulose(HEC) on the Surface Morphology and Mechanical Characteristis of Copper Electrodeposition

The purpose of this study is to identify the effect of additives and composition on copper surface morphology and mechanical characteristics by copper electrodeposition. Additives such as hydroxy ethyl cellulose(HEC), chloride ion were used in this study. Electrochemical experiments allied to SEM, XRD, AFM and four- point probe were performed to characterize the morphology and mechanical characters of copper in the presence of additives. Among various electrodeposition conditions, the minimum surface roughness of copper foil was obtained when electrodeposited at the current density of 200 mA/ for 68 seconds with 2 ppm of HEC. The minimum value of surface roughness(Rms) was 107.6 nm. It is copper foil is good for electromigration inhibition due to preferential crystal growth of Cu (111) deposited in the electrolyte containing chloride ions(10 ppm) and HEC(1 ppm).

Effect of Pulse and Pulse-Reverse Current on Surface Morphology and Resistivity of Electrodeposited Copper

Recently, requirement for the ultra thin copper foil increases with smaller and miniaturized electronic components. In this study, we evaluated the surface morphology, crystal phase ana surface roughness of the copper film electrodeposited by pulse method without using additives. Homogeneous and dense copper crystals were formed on the titanium substrate, and the optimum condition was 25% duty cycle. Moreover, the surface roughness(Ra), , is the smallest value in this condition. It is thought that this copper foil is good for electromigration inhibition due to the preferential crystal growth of Cu (111)

Effect of additives on the elongation and surface properties of copper foils

We report on the effects of additives on the mechanical properties of electrodeposited copper foils. Additives A (leveler), B (brightener) and C (Coll-A) are used in this study, and additive D is used as a Cl− ion. The study results show that there are large differences in surface roughness and elongation, according to whether the additives are added singly or in combination. In the case of additive D, its addition exhibits a high tendency to grow crystals in a (220) direction, and leads to increased elongation; however, it also exhibits the disadvantage of increasing surface roughness. The addition of all four additives results in a low surface roughness of less than 1 um, and shows low tensile strengths and uniform grain sizes. Here, the elongation is 15.6%, which represents an increase in elongation by 34% when compared to that of not adding additives.

Effect of Plasma Treatment Times on the Adhesion of Cu/Ni Thin Film to Polyimide

This study represents the results of the peel strength and surface morphology according to the preprocessing times of polyimide (PI) in a Cu/Ni/PI structure flexible copper clad laminate production process based on the polyimide. Field emission scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopywere used to analyze the surface morphology, crystal structure, and interface binding structure of sputtered Ni, Cu, and electrodeposited copper foil layers. The surface roughness of Ni, Cu deposition layers and the crystal structure of electrodeposited Cu layers were varied according to the preprocessing times. In the RF plasma times that were varied by 100-600 seconds in a preprocessing process, the preprocessing applied by about 300-400 seconds showed a homogeneous surface morphology in the metal layers and that also represented high peel strength for the polyimide. Considering the effect of peel strength on plastic deformation, preprocessing times can reasonably be at about 400 seconds. (Received March 4, 2011)

Effect of Kind and Thickness of Seed Metal on the Surface Morphology of Copper Foil

This study aimed to investigate the effects of the seed layer with copper electroplating on the surface morphology of copper foil. Three kinds of seed metal such as platinum, palladium, Pt-Pd alloy were used in this study. Electrodeposition was carried out with the constant current density of 200 for 68 seconds. Electrochemical experiments, in conjunction with SEM, XRD, AFM and four-point probe, were performed to characterize the morphology and mechanical characteristics of copper foil. Large particles were observed on the surface of the copper deposition layer when a copper foil was electroplated on the 130 nm thickness of Pd, Pt-Pd seed layer. However, a homogeneous surface, low resistivity was obtained when the 260 nm thickness of Pt, Pt-Pd alloy seed layer was used. The minimum value of resistivity was 2.216 at the 260 nm thickness of Pt-Pd seed layer.

구리 박막의 표면형상과 물성에 대한 전류밀도 영향

Abstract This study examined the effect of current density on the surface morphology and physical properties of copperplated on a polyimide (PI) film. The morphology, crystal structure, and electric characteristics of the electrodeposited copperfoil were examined by scanning electron microscopy, X-ray diffraction, and a four-point probe, respectively. The surfaceroughness, crystal growth orientation and resistivity was controlled using current density. Large particles were observed on thesurface of the copper layer electroplated onto a current density of 25 mA/cm 2 . However, a uniform surface and lower resistivitywere obtained with a current density of 10 mA/cm 2 . One of the important properties of FCCL is the flexibility of the copperfoil. High flexibility of FCCL was obtained at a low current density rather than a high current density. Moreover, a reasonablecurrent density is 20 mA/cm 2 considering the productivity and mechanical properties of copper foil.Key wordscurrent density, peel strength, resistivity, flexibility, plating.

Surface Characteristics of the Anodized and Hydrothermally Treated Titanium Affected by the Current Density, Voltage, and Time

This study examined the effect of the current density, anodizing voltage and time on the surface characteristics of titanium during anodic spark oxidation. Anodic spark oxidation was performed at different concentrations of electrolyte composed of DL-α-glycerophosphate (DL-α-GP) and calcium acetate (CA). The specimens were anodized at various conditions (current density, anodizing voltage, and duration) in a fixed electrolyte concentration. Anodized specimens were treated hydrothermally under high pressure steam using an autoclave. Homogeneous anodic oxide films were produced by anodic spark oxidation on the titanium surface with 1~4 μm diameter pores, and the breakdown voltage was changed by the electrolyte concentration. After the hydrothermal treatment, hydroxyapatite crystals formed as an enlarged polygonal shape in the higher concentration of DL-a-GP group and as thin needles in higher concentration of CA group. The bioactivity and osteoblast growth was good for the anodized surface at 340V compared with the groups applied other parameters.