WISOL CO., LTD.

A piezoelectric thin film filter includes: a substrate comprising a parallel cavity constituting the parallel resonator and a series cavity constituting the series resonator; a parallel lower electrode formed on a parallel substrate portion constituting the parallel resonator in the substrate; a series lower electrode formed on a series substrate portion constituting the series resonator in the substrate; a piezoelectric layer formed on the substrate, the parallel lower electrode, and the series lower electrode; and an upper electrode formed on the piezoelectric layer, wherein the series lower electrode comprises a first series lower electrode formed on a portion where the series cavity is formed in the series substrate portion, and a second series lower electrode formed on a portion where the series cavity is not formed in the series substrate portion, wherein a thickness of the first series lower electrode is less than or equal to a predetermined thickness.

An air-gap type film bulk acoustic resonator (FBAR) according to the present invention may include: a substrate comprising an air gap portion on an upper surface thereof; a lower electrode formed on the substrate; a piezoelectric layer formed on the lower electrode; an upper electrode formed on the piezoelectric layer; a protective layer formed on the upper electrode; and a beam structure extended in a dome shape from one side of the upper electrode to define a space portion between the upper electrode and the piezoelectric layer, wherein one end of the beam structure is in contact with the piezoelectric layer.

Disclosed is an air-gap type film bulk acoustic resonator (FBAR) including a substrate including an air-gap portion on a top surface, a lower electrode having a polygonal plate shape above the substrate and configured to surround a top of the air-gap portion, a piezoelectric layer formed above the lower electrode, and an upper electrode formed above the piezoelectric layer. Here, the lower electrode includes an electrode non-deposited area formed between one side plate boundary surface of the polygonal plate and one side air-gap boundary surface of the air-gap portion to expose one part of a top of the air-gap portion.

Provided is an electromagnetic wave shielding sheet, a flexible printed circuit board attached with the electromagnetic wave shielding sheet, and a manufacturing method thereof. The flexible printed circuit board attached with the electromagnetic wave shielding sheet comprises: an electromagnetic wave shielding sheet including a nonwoven fabric having a plated surface and including an adhesive layer adsorbed therein without containing conductive particles, and a nonwoven fabric layer including a first insulating layer formed on the nonwoven fabric; and a flexible printed circuit board attached with the electromagnetic wave shielding sheet, wherein the flexible printed circuit board includes: a base film having a wiring pattern and a ground pattern formed on one side; and a second insulating layer covering the wiring pattern and exposing the ground pattern, and the nonwoven fabric layer having the adhesive layer adsorbed therein is in direct contact with the ground pattern.

A resonator includes: interdigital transducer (IDT) including first electrode including first base on piezoelectric substrate and extended in reference direction, and first protrusions connected to the first base and extended in direction intersecting with the reference direction, and second electrode including second base on the piezoelectric substrate and extended in the reference direction, and second protrusions connected to the second base and extended in direction intersecting with the reference direction, each of the second protrusions extended to have one of the first protrusions inserted between the second protrusion and another second protrusion adjacent to the second protrusion, wherein a width of each of first specific protrusions included between one end of the IDT and first position at first distance from the one end, among the first protrusions and the second protrusions, decreases from first specific protrusion closest to the first position toward first specific protrusion closest to the one end.

A double mode SAW (DMS) filter includes: a plurality of interdigital transducers (IDTs), each having a plurality of Type 1 electrode fingers and a plurality of Type 2 electrode fingers formed on a piezoelectric substrate, wherein one Type 2 electrode finger among the plurality of Type 2 electrode fingers is disposed between two adjacent Type 1 electrode fingers among the plurality of Type 1 electrode fingers, and in a first IDT and a second IDT included in the plurality of IDTs to be adjacent to each other, one Type 1 electrode finger of the second IDT is disposed between two Type 1 electrode fingers of the first IDT. Accordingly, it is possible to provide a DMS filter capable of improving the amount of attenuation in an attenuation band adjacent to the wide band side for the passband and miniaturizing a product by saving space.

A method for manufacturing a film bulk acoustic resonator (FBAR) package with a thin film sealing structure includes: forming an FBAR having a bottom electrode, a piezoelectric layer, and a top electrode on a substrate; forming a plurality of inner pad electrodes electrically connected to the top electrode and the bottom electrode of the FBAR; attaching a PR (photo-resist) film to tops of the inner pad electrodes; etching the PR film to expose the inner pad electrodes to the outside; and forming a sealing layer on top of the PR film and tops of the exposed inner pad electrodes.

Provided is a surface acoustic wave filter with improved attenuation characteristics. The surface acoustic wave filter includes: a plurality of series resonators which are connected between an input terminal and an output terminal; and at least one parallel resonator which connects between a ground terminal and two adjacent series resonators among the plurality of series resonators, wherein at least one of the plurality of series resonators includes: first and second bus bars, which extend parallel to each other in a first direction within first to third areas sequentially arranged on a substrate; a plurality of first interdigital (IDT) transducer electrodes which extend in a second direction perpendicular to the first direction from the first bus bar; and a plurality of second IDT electrodes which extend in the second direction from the second bus bar and are alternately arranged with the plurality of first IDT electrodes, wherein the plurality of first IDT electrodes and the plurality of second IDT electrodes are alternately arranged with a reference period in the second area, are alternately arranged in the first area with a period which gets smaller than a reference period in the direction of one end of the first bus bar, and are alternately arranged in the third area with a period which gets smaller than a reference period in the direction of the other end of the first bus bar.

A film bulk acoustic resonator (FBAR) chip and package structure with an improved temperature coefficient that is capable of being more stable with respect to surrounding temperature changes, without any decrease in performance of Q factor or k2e. The FBAR chip and package structure includes a plurality of FBARs located on a central area of one surface of a substrate and each having a bottom electrode, a piezoelectric material, and a top electrode; and a temperature compensation layer formed around the central area of one surface of the substrate.

A resonator includes an interdigital transducer provided with a main electrode area formed to a shape of a comb on a piezoelectric substrate by a reference pitch in such a manner as to have a unit length along a longitudinal direction thereof and one pair of first electrode areas constituted of one side first electrode area formed to a shape of a comb on the piezoelectric substrate by a first increment pitch obtained by increasing the reference pitch by a first value in such a manner as to have the unit length along the longitudinal direction and the other side first electrode area formed to a shape of a comb on the piezoelectric substrate by a first decrement pitch obtained by decreasing the reference pitch by almost the same value as the first value.