Study On Ultra-precision Cleaning Of Piezoelectric Crystal Device Substrate

With the rapid development of microelectronics technology, the character size of piezoelectric crystal devices diminished ceaselessly,and the demand of the surface cleanliness of substrate becomes higher and higher. In order to ensure the product yield of piezoelectric crystal device, ultra-precision cleaning is a very necessary process. The traditional solvent-based cleaning methods consumes large amount of chemical reagents, higher cost inefficient, harm to human health and pollution to environment.So a new types of cleaning agent and cleaning technology adapted to piezoelectric quartz substrate should be invented. In this paper, we developed a types of water-base cleaning agent mainly consists of surfactant, which possesses effect of efficient,safer and environmental protection.In this paper,through the study of the oil removal efficiency and surface tension of multiple surfactants at first. Then,we investigated the synergism effect of anionic and nonionic surfactants,and five high cleaning efficiency of compound combinations have been chosen at last.Finally,after studying the foam properties of single component surfactant,we obtained the compound combination with low foaming and rapid defoaming by useing the compound defoaming technology without defoaming agent.We firstly considered the oil removal efficiency, surface tension and foam properties of compound anionic surfactant A and compound nonionic surfactants B,and then determined the composition of cleaning agent AFT-101.Later,we examined the influence of the detersive efficiency and oil removal efficiency of the detergent by cleaning temperature, time, and concentration of detergent.Finally,we got the best detersive cleaning process and oil removal cleaning process with the detergent is60℃,5min,5%(wt.)Adopting the multi-slot ultrasonic cleaning process,we examined the impact of the cleaning temperature, time, and concentration on the flaking efficiency of quartz wafer and the average contact angle of the cleaned wafer’s surface.Soon afterwards,we got the optimal ultrasonic flaking process is60℃,10min,5%(wt.) and the optimal ultrasonic cleaning process is60℃,5min,5%(wt.). After AU cleaning process, we studied the wafer surface morphology and the contact angle.In addition,we analysed the composition of wafer’s surface by FTIR and SEM-EDS, the results showed that the surface of quartz wafer cleaned by AU cleaning technique were without organic pollutants and other metal impurities. In other words, there is a high level of cleanliness.