The invention relates to the technical field of
wireless communication, and provides a preparation method of a
surface acoustic wave filter and the
surface acoustic wave filter.The preparation method comprises the steps that S1, a substrate of the
surface acoustic wave filter is obtained; s2, growing a plurality of
metal electrodes and a protective layer on the front surface of the substrate, wherein the protective layer completely covers the plurality of
metal electrodes; s3, presetting a soaking column area on the substrate, and spin-
coating a layer of
photoresist on the back surface of the substrate; s4, removing the
photoresist in the soaking column region through
exposure and development; s5,
etching the soaking column region through
dry etching to form a groove, and removing the residual
photoresist on the substrate; s6, depositing an
electroplating seed layer on the back surface of the substrate, and continuing to complete the
copper electroplating process, so that the groove is filled with
copper; and S7,
grinding the back surface of the substrate until the back surface of the substrate is exposed, and reserving the soaking column formed in the groove to obtain the surface
acoustic wave filter. The surface
acoustic wave filter provided by the invention can effectively improve the
thermal damage resistance of the device under the working condition of
high input power.