| Title |
Surface Treatment : Effect of Frequency on Properties of Film in Cu Electroplating using Square Pulse Current |
| Authors |
민병승(Byung Seung Min); 정원섭(Won Sub Chung); 김인곤(In Gon Kim) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Copper; Electrodeposits; Pulse current; High frequency; Leadframe |
| Abstract |
Recently, copper electrodeposits having more fine grains are required in the lead frame manufacturing process such as lead bending and wire bonding. These processes could not be achieved with a conventional DC copper electrodeposits, which resulted in a cracking or poor bonding with lead wire. In this study, square pulse current was conducted in order to overcome these problems. Prior to plating, the substrate was electropolished, cleaned in deionized water, activated in 5% H_2SO_4 and then transferred immediately to the plating solution. The deposition thickness was 1 ㎛. Cu was electro-plated onto A42(Fe 58% + Ni 42 alloy) sheet from cyanide-Cu bath by DC and high frequency pulse current. Morphology of plating surface was studied by the scanning probe microscope and optical microscope. The corrosion resistance of each plated specimens were studied by A.C Impedance test. Some of our results are summarized as follows; The cathode current efficiency was increased with increasing pulse frequency. XRD analysis shows that microstructure of high frequency pulse deposits develops into more anisotropic pattern than that of DC deposit. Corrosion resistance increased with increase in pulse frequency. |