Development Of VHF Equipment For Sacrificial Layer Release Of MEMS Devices

MEMS is developed from microelectronics technology,using existing mature technologies and materials of semiconductors.In addition to adopting these mature processes,MEMS also focuses on ultra-precision machining,which involves microelectronics,materials,mechanics,and mechanics.,chemistry and other subject areas.The MEMS industry has both national strategic needs and strong market demands.The VHF fumigation system for MEMS processing is in a monopoly state of foreign companies.Therefore,this study carried out the localization of HF gas phase fumigation system.The main contents of this paper are as follows.:1)Develop a test VHF fumigation system for product prototype verification.The developed equipment can achieve an on-chip uniformity of about 25%,but the die is still prone to adhesion failure,which can only meet the research and development needs and cannot be applied to mass production.2)Development of mass production VHF fumigation system,first introduced two common design principles of mass production VHF system.In the development of a generation of VHF fumigation system,the air bubble method of alcohol bubbling was adopted,and the core components of the equipment and the software control interface were designed in detail.The first generation VHF fumigation system can achieve a fumigation rate of 500 (?)/min,an on-chip uniformity of about 7%,but the stability is poor,and the SPC monitoring data fluctuates between 300 and 700 (?)/min.Then,the equipment,process and operation were deeply excavated.After the implementation of the measures,the stability was improved significantly.The SPC monitoring data was stable between 350～650 (?)/min,and also developed for the second generation VHF fumigation system.Provides experience.In the development of the second-generation VHF fumigation system,targeted optimization according to the defects of the first generation equipment,optimization of temperature control,alcohol control optimization,cavity vacuum optimization,program control optimization,the uniformity of equipment developed can be achieved Within 5%,the stability is very good,the basic control is within 400～600(?)/min.In addition to the individual data drift,most of the data can be maintained between 500～550(?)/min,and the process capability is greatly improved,satisfying the process and products.Demand.3)The application cases of HF gas phase fumigation system in MEMS accelerometers,as well as product anomalies occurring during the production process,such as the dropping of silicon nitride foam material and the abnormality of filaments at the edge of aluminum strip,were studied.Finally,I shared the abnormal cases and routine maintenance methods of the equipment.