Manufacturing method of terminal SAW filter

Abstract

The embodiment of the invention discloses a manufacturing method of a terminal SAW filter. The manufacturing method comprises the following steps of: selecting a substrate and a piezoelectric crystal;engraving a mounting circuit on the substrate; dividing an installation area for installing the piezoelectric crystal; forming a welding groove in the installation area; filling soldering tin in thewelding groove; forming a protective layer outside the installation area of the substrate; fixing the piezoelectric crystal on the substrate through the protective layer; heating and extruding the piezoelectric crystal, connecting the piezoelectric crystal with the substrate through soldering tin; fixing a cover plate above the piezoelectric crystal to form a sealed cavity; filling a sealant in the installation area to fix the cover plate for the second time; welding pins connected with an installation circuit on the substrate, when the filter is used, filling the welding groove with solderingtin, ejecting the soldering tin out of the welding groove through thermal expansion and cold contraction of the expansion block in the welding process, recycling redundant soldering tin through an overflow groove, and therefore, the installation angle of the piezoelectric crystal can be effectively controlled while stable connection of the piezoelectric crystal is achieved.

Description

technical field [0001] The invention relates to the technical field of filters, in particular to a method for manufacturing a terminal SAW filter. Background technique [0002] SAW filter is also called surface acoustic wave filter. SAW is mainly generated and propagated on the surface of piezoelectric substrate material, and its amplitude decreases rapidly as the depth of the substrate material increases. The basic principle of SAW filter is The structure is to make two acoustic-electric transducers-interdigital transducers on the polished surface of the substrate material with piezoelectric properties, which are used as the transmitting transducer and the receiving transducer respectively. The RF signal is converted into an acoustic wave, propagated on the surface of the substrate, and after a certain delay, the receiving transducer converts the acoustic signal into an electrical signal for output. [0003] Due to the excellent characteristics of the SAW filter, it is wid...

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Problems solved by technology

[0005] For this reason, the embodiment of the present invention provides a terminal SAW filter manufacturing method to solve the problem that in the prior art, too much or too small solder is likely to cause false soldering or a certain deviation in the installation angle of the piezoelectric crystal. When the angle is skewed, it is easy to cause a certain change in the size of the cavity, resulting in certain flaws in the produced filter

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