The different processes illustrate that, besides the recirculative and spray assisted stencil-cleaning equipment, no significant differences flux residues with regard to the cleaning ability under capillaries and components were observed. To optimize the results for the latter two one could alter the process parameter and potentially even use certain additives. Standoff effect on the flux removal cleaning result underneath components. It was established that the cleaning result between the smaller (0.002 inches, 2MIL) and bigger standoff spacing (0.008inches, 8MIL) only slightly differed from the results obtained using the 0.004inch (4MIL) standoff. Therefore, one flux removal could neither observe an improved result with higher standoffs nor a worse outcome for lower standoffs (Figure 9).
Influence of time and temperature with reference to the cleaning result underneath components for equal amount of contamination and standoff. An flux residues increase in temperature led to a drastic acceleration in the cleaning, whereas an increase in the cleaning cycle time only marginally affected the results. One can therefore conclude, that a process optimization is easier achieved through increased temperature than through a change in time. It is important to note however, that not the result (i.e. the ability to remove a particular residue) but solely the cleaning rate is affecting the overall outcome. Influence Dr.Wack of the component geometry with regard to the cleaning result flux residues under components.
Glass coupons were placed and soldered (flux jelly was used) on top of pre-bumped CSP areas (30 and 20 MIL respectively) to simulate the influence of mechanical barriers of BGA-type connections. The standoff, which is predetermined by Ionox the height flux residues of the solder ball, was found to be 0.006 inches (6MIL, for the 0.03 inch pitch) and 0.002 inches (2 MIL, for 0.02 inch pitch size), respectively. The conclusion that was reached after comparing the cleaning results to all previous experiments showed no significant difference.
The investigators therefore conclude, that the influence of mechanical barriers for a given grid pattern are negligible and that only the overall geometry of the flux residues capillary spaces is relevant. However, one cannot conclude whether this observation is Swax applicable to smaller grid arrays. An optical inspection for to the evaluation of the cleaning result proved to be simplest and most flux removal conclusive. For all ionic Bioact contamination measurements that were performed, values below 0.3 mg NaCl Eq./cm2 were found. This certainly confirms the results obtained during the optical inspection. The electrical cleanliness levels underneath the glass coupons were systronic ascertained via SIR test, which is known to be the most sensitive procedure currently available (Fig.10).
Ultrasonic cleaning cleaning solvent pcb cleaning aqueous cleaning ultrasonic cleaning systems aqueous cleaning systems flux residue flux residues Dr. Ok. Wack Ultrasonic cleaning equipment Ultrasonic cleaning system