Papers by Keyword: Copper Electroplating

Abstract: High throwing power (TP) copper electroplating has become increasingly important for interconnect fabrication in IC packaging substrates and printed circuit boards (PCB) due to the demands of electronic products with high-density interconnection (HDI). In this study, the factors that influence throwing power of PCB such as plating liquid concentration, current density, organic additive composition and vibration frequency have been investigated. The results showed that, within the scope of this study, with the increase of the current density, PCB throwing power ability decreased gradually, descending grade range up to 5%. Throwing power ability gradually increased as different vibration frequency from 10s to 30s. The orthogonal experimental design was employed to investigate key factors out of all available operation parameters to influence TP. It turned out that the copper sulfate concentration of 30g/L, a current density of 5 ASF, a brightener concentration of 60ml/ kAH and the vibration frequency of 30s are advantageous to achieve best throwing power in the electrodeposition processes.

Abstract: This paper presents the design, fabrication, and characterization of micro planar inductors on a microwave magnetic material (YIG). Planar spiral inductors were designed for monolithic DC-DC converters in System-In-Package with 100 MHz switching frequency (1 W, V_in= 3.6 V, V_out= 1 V). A microwave magnetic substrate (YIG) serves as mechanical support, and also presents a double purpose by increasing inductance value and reducing electromagnetic interferences (EMI). This last point is critical to improve the behavior of a switching mode power supply (SMPS). In order to obtain an optimal design for the inductor, geometrical parameters were studied using Flux2D simulator and an optimized 30 to 40 nH spiral inductor with expected 25 mΩ R_DC, 3 mm² footprint area was designed. Subsequently, samples have been fabricated by electroplating technique, and tested using a vector network analyzer in the 10 MHz to 100 MHz frequency range. Results were then compared to the predicted response of simulated equivalent model.

Abstract: The acid dipping-plating pretreatment was applied on iron substrate prior to no-cyanide copper plating process. After being pretreated in dipping solution, the thin copper film formed on iron substrate which could change the cathode electronic potential and enhance the copper plating rate in the follow-up copper electroplating. As a comparation, the iron substrate was directly electroplated in another copper plating bath without dipping-plating pretreatment (DPr). The effects of temperature and electric current density on the copper plating rate were investigated in both process with DPr and process without DPr. And the mechanism was discussed.

Abstract: In general, the S-N curve in railway axles was mainly carried out under 107-108 cycles, while the service area of a railway axle is 108-109 cycles. The strain gages using electrical resistance have been used to measure stresses in railway vehicle wheelsets. However, there are some problems with strain gages using electrical resistance for railway axles. For example, the measured data is for special or limited intervals only. Strain gage installation is complicated, that is, it requires lead wires for measurement. The design of railway axles makes use of data that was obtained many years ago. The applied stresses in wheelsets running for a long time and in new railway vehicle wheelsets have not been studied clearly yet. It is necessary to carry out stress monitoring for more than 108 cycles to evaluate the safety of railway wheelset. Therefore, it is necessary to develop new stress monitoring techniques that can easily measure the working stress of the wheelset. In the present paper, the stress measurement technique of copper electroplating is considered because of its high potential for this purpose.