The Design And Manufacture Of Flip Chip Saw Filter For Mobile Phone Navigation Adapted To Three Modes

SAW filter is a kind of electronic device used to process signals.Just like other filters,it can transfer useful signals and filter interference signals.Its working principle is that adding electrical signal on input port,the signal emits sound waves,the waves are processed during transferring,finally the wave signal change into electrical signal on output port.In recent years,with the rapid development of mobile communication business,a large amount of filters is demanded.Saw filter has many advantages,such as high frequency performance,good consistency,small size etc,so it has been used in many fields.Scientists and engineers pay much more attention on saw devices in order to use it well.The mobile communication system is developing in the direction of high-frequency and multi-mode;which demands SAW filters can offer high performance.High frequency,broad band,low insertion loss and small size have become difficulties and hot pots in the development of SAW devices.At present,mobile communication market needs a kind of SAW filter,which can adapt to three modes(COMPASS,GPS,GLONASS),used for navigation in mobile phones.Middle frequency:1575MHz,Band pass:40MHz,Insertion loss less than 1.8dB,Size:1.1mmx0.9mx0.5mm.We have the ability to design and manufacture this kind of device.If succeed,the project will bring large economic values,also we can acquire knowledge and experience on flip chip sealing process,and we will break the monopoly situation on SAW devices used for mobile phones by Japanese and Western countries.The thesis is based on designing and producing the above mentioned SAW filter,analysis produce process,emphasis on flip chip bonding,find process problems and give improvement measures.Chip design using DMS structure,electron beam evaporation of aluminum film,S1805 photo resist,UV light step photography and wet etching process.Device packing adopts flip chip process,including bump bonding,ultrasonic flip bonding,and molding.After package sealing,we test the devices,finding that parameters,stability,reliability,and size of the filter meet the design requirement.We are satisfied with the result.The package size of the device is reduced from 1.4mm X 1.1mm X 0.6mm to 1.1 mm X 0.9mm X 0.5mm,which means we reach a high level in SAW filter field of the world.