Electrochemical Migration on Electronic Chip Resistors in Chloride Environments

Abstract

Abstract-Electrochemical migration behavior of end terminals on ceramic chip resistors (CCRs) was studied using a novel experimental setup in varying sodium chloride concentrations from 0 to 1000 ppm. The chip resistor used for the investigation was 10-kΩ CCR size 0805 with end terminals made of 97Sn3Pb alloy. Anodic polarization behavior of the electrode materials was investigated using a microelectrochemical setup. Material makeup of the chip resistor was investigated using scanning electron microscopy (SEM)/energy dispersive spectroscopy and focused-ion-beam SEM. Results showed that the dissolution rate of the Sn and stability of Sn ions in the solution layer play a significant role in the formation of dendrites, which is controlled by chloride concentration and potential bias. Morphology, composition, and resistance of the dendrites were dependent on chloride concentration and potential.

Effect of pulsed voltage on electrochemical migration of tin in electronics

“…For comparison, the resistance of the dendrites formed for Sn-Pb and lead free solder alloys under distilled water varies in the range of kOhms [3]. Similar resistance values were reported in the study of ECM on electronic chip resistors in chloride environments [6]. An increase of dendrite current with increase of duty cycle observed for 15.6 lg cm -2 of NaCl indicated that the longer ON cycles is more dynamically favourable condition for dendrite growth and suggests different morphology of dendrites formed under pulsed voltage.…”

“…However, the process of ECM can be also influenced by the ionic contamination dissolved in the water layer [5][6][7], pH level, bias voltage [3,8], and the distance between the electrodes [9,10]. The conductivity of the water layer adsorbed on a PCBA is determined by the ionic contamination present on the surface as it affects the ion transport between the anode and cathode.…”

“…The tests are typically performed under water droplet condition [2][3][4][5][6][7], thin electrolyte layers [12,13], or at elevated humidity/temperature conditions [14][15][16][17]. The test specimens usually used are the surface insulation resistance (SIR) patterns and surface mount components [5][6][7].…”

Electrochemical migration of Sn and Sn solder alloys: a review

“…Zhong et al 53 studied the ECM of Sn under 100 mm-thick electrolyte layer containing 1 mM Cl À with a bias voltage of 3 V. They found that the initiation stage took about 100 seconds while the total ECM time (from the beginning of ECM test to the time when a short circuit occurs) was 119 seconds. Minzari et al 45 reported a similar phenomenon during the ECM of Sn-37Pb solder alloy in 10 ppm NaCl solution at a bias voltage of 3 V.…”

On the Effects of Atmospheric Particles Contamination and Humidity on Tin Corrosion

“…It is based on the observation that in impedance graphs ( Fig. 3), along the humidification curve, a dry region is followed first by a deliquescent region (sharp decrease in impedance), and then by a hygroscopic growth region (due to continuous condensation of water); the reverse happens during dehumidification when evaporation took place, followed by crystallization (sharp increase in impedance), which in turn led once again to a dry state.The ECM is typically studied by applying constant voltage and measuring the LC between interdigitated electrodes [29]. Under these conditions, the "BioLogic VSP" potentiostat was used to measure the low current passing through a conductive layer at 5 V DC and as a function of RH (30.0-90.0% RH).…”