Experimental Analysis of Initiation Mechanism of Bubbles in Ultra-Clean Pumps Circulating Hydrogen Peroxide

For wet cleaning systems in semiconductor manufacturing process, hydrogen peroxide
$(\mathrm{H}_{2}\mathrm{O}_{2})$
is an essential ingredient of many cleaning agents such as SPM
$(\mathrm{H}_{2}\mathrm{O}_{2}+\mathrm{H}_{2}\text{SO}_{4})$
, SC-1
$\mathrm{H}_{2}\mathrm{O}_{2}+\text{NH}_{3}\cdot \mathrm{H}_{2}\mathrm{O})$
, and SC-2
$(\mathrm{H}_{2}\mathrm{O}_{2}+\text{HCl})$
. In practical engineering applications, undesirable bubbles were observed downstream of ultra-clean pumps, the crucial fluid power components, when dealing with cleaning agents containing
$\mathrm{H}_{2}\mathrm{O}_{2}$
. In this study, to investigate how bubbles initiate in ultra-clean pumps dealing with hydrogen peroxide, experiments were conducted in a closed-loop system, simulating a batch-type wet cleaning bench. High-speed visualization was performed in different operating conditions of the system. Bubbles initiated in the bellow chamber and at the bottom of the inlet valve were described and analyzed based on high-speed sequences. Titration was utilized to determine whether chemical decomposition occurs during mechanical handling. The pump capacity curve during
$\mathrm{H}_{2}\mathrm{O}_{2}$
circulations was also obtained and compared with that when dealing with ultra-pure water. The findings can contribute to a better understanding of the initiation mechanism of bubbles in pumps when handling
$\mathrm{H}_{2}\mathrm{O}_{2}$
, and make a guideline for optimization.