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Tetramethylammonium hydroxide (TMAH) is widely used in the electronics industry as a developer for TFT-LCDs and IC positive photos, an etchant for silicon wafers, and a super-pure cleaning agent in the CMP process; it is also used as a developing solution in liquid crystal displays. With the rapid advancement of the electronics industry, PCB technology is also developing at a swift pace. As a key process in PCB pattern formation, development directly affects the quality of the circuit traces as well as that of the solder resist. The quality requirements for development are such that there should be no incomplete development, no over-development, and no issues such as trace breaks or loss of solder resist. The exposed copper area after development should be 50% to 60% (half of the total developed area). Therefore, the control of developer concentration plays a very important role in the development process. According to the process requirements, the existing TMAH cleaning solution with a concentration of 25% needs to be diluted to the target concentration of 2.38%. Online instruments are required to provide accurate measurements of the TMAH concentration, thereby enabling the precise preparation of the developing solution at the desired concentration. Currently, the industry commonly uses sampling-and-analysis systems to measure the concentration of TMAH; the measurement process takes approximately 20 minutes. This method does not provide real-time capability, as changes in concentration along the process pipelines cannot be monitored in a timely manner, resulting in delayed control responses. To increase production volume, it is necessary to improve the efficiency of formulating the developing solution and reduce the time required for this process; therefore, real-time monitoring of the TMAH concentration is essential, along with stricter requirements for process control. The TMAH online concentration meter, which utilizes the principle of ultrasonic sound speed, can meet the requirements for online monitoring and offers high measurement accuracy. The online concentration meter for tetramethylammonium hydroxide (TMAH) utilizes the fact that there is a very good correlation between changes in ultrasonic sound speed and the concentration of TMAH solution. The actual concentration of the solution is obtained through conversion. This measurement principle features good stability and high precision; it is suitable for installation in pipes or on container walls, as well as for various other installation methods. I would like to recommend an online ultrasonic concentration meter that can be widely used for the online monitoring of TMAH at concentrations of 25% and 2.38%. The precision can reach over 0.003%. We have extensive experience in applications for liquid crystal panels and the semiconductor industry; feel free to contact us for more details. Those who are interested can get in touch. 18615997765