KR102439904B1 - Filter and front-end module including the same - Google Patents

Abstract

A filter according to an embodiment of the present invention includes a plurality of at least one series resonator and at least one shunt resonator formed by a substrate, a first electrode sequentially stacked on the substrate, a piezoelectric layer, and a second electrode. and a cap for accommodating the plurality of volume sound resonators, and at least one switch provided in the cap.

Description

FILTER AND FRONT-END MODULE INCLUDING THE SAME

The present invention relates to a filter module.

With the rapid development of mobile communication devices, chemical and bio devices, the demand for small and lightweight filters, oscillators, resonant elements, and acoustic resonant mass sensors used in these devices has also increased. is increasing

A thin film volume acoustic resonator (FBAR) is known as a means for implementing such a small and lightweight filter, an oscillator, a resonance element, an acoustic resonance mass sensor, and the like. The thin film volume acoustic resonator has the advantage that it can be mass-produced at a minimum cost and can be implemented in a very small size. In addition, it is possible to implement a high quality factor (Q) value, which is the main characteristic of the filter, and can be used in the micro frequency band, especially in the PCS (Personal Communication System) and DCS (Digital Cordless System) bands. There are advantages to being able to

Recently, as a wireless terminal supports a plurality of bands, a plurality of filters to cover a plurality of bands are employed in the wireless terminal. However, as the number of bands increases, when the number of filters in charge of the band increases, there is a problem in that the signal processing process becomes complicated, and the manufacturing cost and size of the filter module increase.

An object of the present invention is to provide a filter, a filter module, and a front-end module supporting a larger number of bands.

A filter according to an embodiment of the present invention includes a plurality of at least one series resonator and at least one shunt resonator formed by a substrate, a first electrode sequentially stacked on the substrate, a piezoelectric layer, and a second electrode. and a cap for accommodating the plurality of volume sound resonators, and at least one switch provided in the cap.

The filter module according to an embodiment of the present invention may include a plurality of filters, and at least one filter covers bands having overlapping bandwidths, thereby reducing the size and manufacturing cost of the filter module.

1A is a table provided to explain frequencies of a transmission band and a reception band of a communication band according to an example.
1B is a diagram provided to explain a filter module and a communication band supported by the filter module according to an example.
2 is a diagram provided to explain a communication band supported by a filter module according to an embodiment of the present invention.
3 is a diagram provided to explain a filter module according to an embodiment of the present invention.
4 is a diagram provided to explain a mode of a filter module according to an embodiment of the present invention.
5 is a diagram provided to explain a filter module according to an embodiment of the present invention.
6 is a diagram provided to explain a filter module according to an embodiment of the present invention.
7 is a diagram provided to explain a filter module according to an embodiment of the present invention.
FIG. 8 is a diagram provided to explain a method of changing an upper limit frequency according to an embodiment of FIG. 3 .
9 is a diagram provided to explain a method of changing an upper limit frequency according to another embodiment of FIG. 3 .
FIG. 10 is a diagram provided to explain a method of changing a lower limit frequency according to an embodiment of FIG. 3 .
11 is a diagram provided to explain a method of changing a lower limit frequency according to another embodiment of FIG. 3 .
12 is a diagram provided to explain a method of changing a lower limit frequency according to another embodiment of FIG. 3 .
13 is a schematic diagram provided to explain a connection method between a filter module and a switch according to an example.
14 is a cross-sectional view showing a filter module according to an embodiment of the present invention.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present embodiments may be modified in other forms, or features of various embodiments may be combined with each other. Even if a matter described in one embodiment is not described in another embodiment, it may be combined with the description of another embodiment unless there is a contrary or contradictory description in the other embodiment.

The shapes and sizes of elements in the accompanying drawings may be exaggerated for clearer description, and elements indicated by the same reference numerals in the drawings may be understood as identical or similar elements. In addition, in this specification, terms such as 'upper', 'upper surface', 'lower', 'lower surface', and 'side' are expressed based on the direction of the accompanying drawings, and in fact, depending on the direction in which the element is disposed It could be different.

1A is a table provided to explain frequencies of a transmission band and a reception band of a communication band according to an example. 1B is a diagram provided to explain a filter module and a communication band supported by the filter module according to an example.

The communication band shown in FIG. 1A may be a communication band of Long Term Evolution (LTE), and the communication bands B1-B25, B65, B66 are a transmission band (Tx) referred to as an up-link band and a down- It may include a receive band (Rx) referred to as a down-link band.

Referring to FIG. 1B , the filter module may include a plurality of filters, and the plurality of filters may be in charge of a transmission band and a reception band of a communication band supported by the filter module.

Assuming that the filter module supports the communication bands B1, B2, B3, B4, and B25, a plurality of filters are used for the transmission and reception of radio frequency signals, the communication bands B1_Tx, B1_Rx, B2_Tx, B2_Rx, B3_Tx, B3_Rx, B4_Tx , B4_Rx, B25_Tx, B25_Rx.

Assuming that a plurality of filters are composed of six filters (F1-F6) corresponding to less than 10 the number of transmission bands and reception bands required, some filters among the six filters (F1-F6) have a bandwidth A part of the band is responsible for the two overlapping bands.

Referring to FIG. 1B , filter F1 may cover communication bands B3_Tx and B4_Tx, filter F2 may cover communication band B3_Rx, filter F3 may cover communication band B1_Tx, and filter F4 may cover communication band B1_Rx , B4_Rx can be in charge. Also, the filter F5 may cover the communication bands B2_Tx and B25_Tx, and the filter F6 may cover the communication bands B2_Rx and B25_Rx. For example, filters F1, F2, F3, and F4 may constitute a quadplexer, and filters F5 and F6 may constitute a duplexer.

Although the filter module of FIG. 1b supports a larger number of communication bands than the plurality of filters provided, in order to reduce the size occupied by the filter module in a wireless terminal that is becoming highly integrated and slim in recent years, more communication bands are converted into one filter module. need to be responsible for

2 is a diagram provided to explain a communication band supported by a filter module according to an embodiment of the present invention.

2, assuming that the filter module supports the communication bands B1, B2, B3, B4, B25, and B66, a plurality of filters employed in the filter module include communication bands B1_Tx, B1_Rx, B2_Tx, B2_Rx, B3_Tx, B3_Rx, B4_Tx, B4_Rx, B25_Tx, B25_Rx, B66_Tx B66_Rx are in charge.

1A and 2 , the communication bands B3_Tx, B4_Tx, and B66_Tx may partially overlap the bandwidth, and the communication bands B3_Rx, B25_Tx, and B2_Tx may partially overlap the bandwidth, and the communication bands B1_Tx, B25_Rx, A portion of the bandwidth may overlap with B2_Rx, and a portion of the bandwidth may overlap with the communication bands B1_Rx, B4_Rx, and B66_Rx.

The filter module according to an embodiment of the present invention may include a plurality of filters, and at least one filter covers bands having overlapping bandwidths, thereby reducing the size and manufacturing cost of the filter module.

3 is a diagram provided to explain a filter module according to an embodiment of the present invention.

According to an embodiment of the present invention, at least one filter among a plurality of filters employed in the filter module may cover at least two communication bands in which a part of the bandwidth overlaps.

1A and 3 , the filter module may include a plurality of filters F1, F2, F3, and F4. The plurality of filters F1, F2, F3, and F4 may constitute one of a quadplexer and a duplexer.

Assuming that the filter module includes four filters (F1, F2, F3, F4), filter F1 may be responsible for communication bands B3_Tx, B4_Tx, B66_Tx in which part of the bandwidth overlaps, and filter F2 is part of the bandwidth may cover the overlapping communication bands B3_Rx, B25_Tx, B2_Tx, the filter F3 may cover the communication bands B1_Tx, B25_Rx, B2_Rx, in which a part of the bandwidth overlaps, and the filter F4 may be in charge of the communication bands B1_Rx, B4_Rx in which a part of the bandwidth overlaps. , can be in charge of B66_Rx. As shown in FIG. 3 , when four filters F1 to F4 cover bands having overlapping bandwidths, the number of filters serving the bands may be reduced.

According to an embodiment of the present invention, at least two communication bands covered by at least one filter among the filter modules may have different upper and lower frequencies. For example, filter F2 is a communication band B3_Rx having a lower limit frequency of 1805 [MHz] and an upper limit frequency of 1880 [MHz], B2_Tx having a lower limit frequency of 1850 [MHz] and an upper limit frequency of 1910 [MHz], 1850 [MHz] The communication band B25_Tx having a lower limit frequency of , and an upper limit frequency of 1915 [MHz] may be in charge. In addition, the filter F3 is a communication band B1_Tx having a lower limit frequency of 1920 [MHz] and an upper limit frequency of 1980 [MHz], a communication band B2_Rx having a lower limit frequency of 1930 [MHz] and an upper limit frequency of 1990 [MHz], and 1930 [ The communication band B25_Rx having a lower limit frequency of MHz] and an upper limit frequency of 1995 [MHz] can be covered.

1a, 2 and 3, the interval between the frequency band 1805 [MHz] ~ 1915 [MHz] supported by the filter F2 and the frequency band 192 [MHz] ~ 1995 [MHz] supported by the filter F3 is approximately 5 When the frequency band to which the filter F2 and filter F3 are allocated is used as it is because it is narrow to [MHz], there is a fear that radio frequency signals transmitted and received by the filter F2 and the filter F3 may be interfered with.

In the filter module according to an embodiment of the present invention, when the frequency bands of different filters supporting adjacent frequency bands have a difference of 1 [MHz] to 10 [MHz], the frequency bands of different filters are variable depending on the mode. Thus, it is possible to prevent interference with radio frequency signals transmitted and received by the filter.

As an example, the filter F2 may vary the allocated frequency band by adjusting the upper limit frequency in the range of 1880 [MHz] to 1915 [MHz], and the filter F3 adjusts the lower limit frequency in the range of 1920 [MHz] to 1930 [MHz] can be adjusted to vary the allocated frequency band.

4 is a diagram provided to explain a mode of a filter module according to an embodiment of the present invention.

Referring to FIG. 4 , the filter module may operate in a first mode and a second mode. Regardless of the mode, the assigned bandwidths to the filters F1 and F4 may be fixed, and the assigned bandwidths to the filters F2 and F3 may be adjusted to avoid interference with frequency signals. For example, the bandwidth of the filter F2 may be adjusted by changing the upper limit frequency, and the bandwidth of the filter F3 may be adjusted by changing the lower limit frequency. In this case, when the bandwidth is enlarged by increasing the upper limit frequency of the filter F2, the lower limit frequency of the filter F3 may increase and thus the bandwidth may be reduced. In addition, when the bandwidth of the filter F2 is decreased due to the decrease of the upper limit frequency, the lower limit frequency of the filter F3 is decreased and thus the bandwidth is increased.

Specifically, the upper limit frequency of the filter F2 is increased to cover the communication bands B3_Rx, B_25Tx, and B2_Tx in the first mode (Mode 1), the bandwidth can be expanded, and the communication band B3_Rx in the second mode (Mode 1) Bandwidth may be reduced as the upper limit frequency is reduced to cover.

In addition, the filter F3 may reduce the bandwidth by increasing the lower limit frequency to cover the communication bands B_25Rx and B2_Rx in the first mode (Mode 1), and reduce the communication bands B1_Tx, B_25Rx, and B2_Rx in the second mode (Mode 2). The bandwidth may be reduced by reducing the lower limit frequency to be covered.

5 is a diagram provided to explain a filter module according to another embodiment of the present invention. Since the filter module of FIG. 5 is similar to the filter module of FIG. 3 , the same or overlapping content will be omitted and the differences will be mainly described.

Referring to FIG. 5 , the filter module may include a plurality of filters F1, F2', F2', F3, and F4. The plurality of filters F1, F2', F2', F3, and F4 may constitute one of a quadplexer and a duplexer. Assuming that the filter module includes five filters (F1, F2', F2', F3, F4), filter F1 may be responsible for the communication bands B3_Tx, B4_Tx, and B66_Tx, and the filter F2` may cover the communication band may be responsible for B3_Rx, filter F2`` may be responsible for B25_Tx, and B2_Tx, filter F3 may be responsible for communication bands B1_Tx, B25_Rx, and B2_Rx, and filter F4 may be responsible for B1_Rx, B4_Rx, and B66_Rx can do.

Comparing FIGS. 3 and 5, the filter module of FIG. 5 separates the filters responsible for the communication bands B3_Rx, B25_Tx, and B2_Tx into two, so that the filters F2' and F2' can be easily manufactured. At this time, the filters F2' and F2'' operate in different modes, so that the filters F2' and F2'' can avoid interference between the supported frequency bands.

6 is a diagram provided to explain a filter module according to another embodiment of the present invention. Since the filter module of FIG. 6 is similar to the filter module of FIG. 3 , the same or overlapping content will be omitted and the differences will be mainly described.

Referring to FIG. 6 , the filter module may include a plurality of filters F1, F2, F3′, F3′, and F4. The plurality of filters F1, F2, F3', F3'', and F4 may constitute one of a quadplexer and a duplexer. Assuming that the filter module includes five filters (F1, F2, F3`, F3``, F4), filter F1 may be responsible for communication bands B3_Tx, B4_Tx, and B66_Tx, and filter F2 may be for communication band B3_Rx , B25_Tx, and B2_Tx, filter F3' may be responsible for communication band B1_Tx, filter F3' may be responsible for B25_Rx, and B2_Rx, and filter F4 may be responsible for B1_Rx, B4_Rx, and B66_Rx can do.

Comparing FIGS. 3 and 6, the filter module of FIG. 6 separates the filters responsible for the communication bands B1_Tx, B25_Rx, and B2_Rx into two, so that the filters F3' and F3' can be easily manufactured. At this time, the filters F3' and F3'' operate in different modes, so that the filters F3' and F3'' can avoid interference between the supported bands.

7 is a diagram provided to explain a filter module according to an embodiment of the present invention. Since the filter module of FIG. 7 is similar to the filter module of FIG. 3 , the same or overlapping content will be omitted and the differences will be mainly described.

Referring to FIG. 7 , the filter module may include a plurality of filters F1, F2`, F2``, F3`, F3``, and F4. The plurality of filters F1, F2', F2', F3', F3', and F4 may constitute one of a quadplexer and a duplexer. Assuming that the filter module includes six filters (F1, F2', F2', F3', F3', F4), the filter F1 may cover the communication bands B3_Tx, B4_Tx, and B66_Tx, and the filter F2` may be responsible for communication band B3_Rx, filter F2`` may be responsible for B25_Tx, and B2_Tx, filter F3` may be responsible for communication band B1_Tx, and filter F3`` may be responsible for B25_Rx, and B2_Rx may be in charge, and the filter F4 may be in charge of B1_Rx, B4_Rx, and B66_Rx.

3 and 7, the filter module of FIG. 7 separates the filters responsible for the communication bands B3_Rx, B25_Tx, and B2_Tx into two, so that the filters F2` and F2`` can be easily manufactured, and communication By separating the filters responsible for the bands B1_Tx, B25_Rx, and B2_Rx into two, the filters F3' and F3' can be easily manufactured.

Filters F2` and F2`` operate in different modes, so that filters F2` and F2`` can avoid interference between supported bands, and filters F3` and F3`` operate in different modes, F3`, F3`` can avoid interference between supported bands.

FIG. 8 is a diagram provided to explain a method of changing an upper limit frequency according to an embodiment of FIG. 3 . Fig. 8(a) is a circuit diagram showing the filter F2 of Fig. 3, and Fig. 8(b) is a graph showing the change in the frequency band of the filter F2.

Referring to FIG. 8A , the filter F2 according to an embodiment of the present invention may include a plurality of resonators. Here, each of the plurality of resonators may include a film bulk acoustic resonator (FBAR).

The filter F2 may include at least one series unit 10 and at least one shunt unit 20 disposed between the at least one series unit 10 and the ground. As shown in FIG. 8 , the filter F2 may be formed in a ladder type filter structure, or alternatively, may be formed in a lattice type filter structure.

The at least one series unit 10 may be disposed between a signal input end RFin to which an input signal is input and a signal output end RFout to which an output signal is output, and the at least one shunt unit 20 includes at least one series It may be disposed between the connection node of the part 10 and the signal output terminal RFout and the ground or between the connection node of the at least one series part 10 and the signal input terminal RFin and the ground.

Although the filter F2 is illustrated as having one series part 10 and one shunt part 20 in FIG. 8(a), a plurality of series part 10 and shunt part 20 may be provided. , when a plurality of series units 10 and shunt units 20 are provided, a plurality of series units 10 are connected in series with each other, and a node between the series units 10 to which the shunt units 20 are connected in series and It can be placed between the ground. The shunt unit 20 may include at least one shunt resonator Sh, and may further include a trimming inductor L disposed between the shunt resonator Sh and the ground.

The at least one series unit 10 may include a first series resonator S1 and a second series resonator S2 . The first series resonator S1 and the second series resonator S2 may operate selectively. The first series resonator S1 and the second series resonator S2 may be connected in parallel to each other through the first switch SW1 and the second switch SW2 . Specifically, the first series resonator S1 and the first switch SW1 may be connected in series with each other, and the second series resonator S2 and the second switch SW2 may be connected with each other in series, and in series with each other. The first series resonator S1 and the first switch SW1 connected to each other and the second series resonator S2 and the second switch SW2 connected in series with each other may be connected in parallel. The first series resonator S1 , the second series resonator S2 , the first switch SW1 , and the second switch SW2 may be manufactured as a one-chip.

The first switch SW1 and the second switch SW2 may perform switching operations in different modes. For example, in the first mode (Mode 1), the first switch SW1 may be turned on, and the second switch SW2 may be turned off, and in the second mode (Mode 2), the first switch SW1 may be turned off, and the second switch SW2 may be turned on.

The first series resonator S1 and the second series resonator S2 may have different resonant frequencies and anti-resonant frequencies, for example, in the first series resonator S1 operating in the first mode (Mode 1). The resonant frequency may be higher than the resonant frequency of the second series resonator S2. Accordingly, referring to FIG. 8(b), in the first mode (Mode 1), the upper limit frequency is increased by the first series resonator S1, so that the bandwidth can be expanded, and in the second mode (Mode 2) , as in the second mode (Mode 2) of FIG. 8(b) by the second series resonator S2, the upper limit frequency is reduced, so that the bandwidth may be reduced.

9 is a diagram provided to explain a method of changing an upper limit frequency according to another embodiment of FIG. 3 .

9 (a) and 9 (b) are circuit diagrams showing a front-end module according to an embodiment of the present invention, Figure 9 (c) is a change in the frequency band of the filter F2 according to an embodiment of the present invention. It is a graph representing

Referring to FIGS. 9A and 9B , the front-end module 1000 according to an embodiment of the present invention includes an antenna 1100 , a filter module 1200 , and a notch filter 1300 . , a switch 1400 and an RF integrated circuit (IC) 1500 . The plurality of filters F1 , F2 , F3 , and F4 of the filter module 1200 may correspond to the filter module of FIG. 3 . The plurality of filters F1 , F2 , F3 , and F4 of the filter module 1200 and the notch filter 1300 may be manufactured as a volumetric acoustic resonator (FBAR), in this case, the filter module 1200 and the notch filter 1300 . ), the switch 1400 may be manufactured as a one-chip.

The antenna 1100 may transmit/receive a radio frequency signal, and the filter module 1200 may transmit and receive a radio frequency signal received through the antenna 1100 or a radio frequency signal transmitted/received through the RF integrated circuit 1500 of a specific frequency band. A filtering operation that passes or removes a component may be performed. The filter module 1200 may correspond to the filter module of FIG. 3 and may include a plurality of filters F1, F2, F3, and F4.

The filter F2 of the filter module 1200 may be selectively connected to the notch filter 1300 according to a mode. Accordingly, the notch filter 1300 may selectively operate. The notch filter 1300 may be disposed between the filter module 1200 and the RF integrated circuit 1500 , or disposed between the filter module 1200 and the antenna 1100 , and may be selectively connected to the filter F2 according to a mode.

Referring to FIG. 9A , a notch filter 1300 and a switch 1400 connected in series with each other may be disposed between the filter module 1200 and the RF integrated circuit 1500 . The switch 1400 is a three-terminal switch having a first terminal connected to the filter module 1200 , a second terminal connected to the RF integrated circuit 1500 , and a third terminal connected to the notch filter 1300 . can The first terminal of the switch 1400 is connected to one of the second terminal and the third terminal to connect the filter module 1200 and the RF integrated circuit 1500 , or the filter module 1200 and the notch filter 1300 . can connect

In the first mode, the switch 1400 directly connects the filter F2 of the filter module 1200 and the RF integrated circuit 1500, and in the second mode, the switch 1400 connects the filter F2 of the filter module 1200 and the filter F2 of the filter module 1200. The RF integrated circuit 1500 may be connected through the notch filter 1300 .

Referring to FIG. 9B , a notch filter 1300 and a switch 1400 connected in parallel to each other may be disposed between the filter module 1200 and the antenna 1100 . In the first mode, the switch 1400 operates to turn on, directly connecting the filter F2 of the filter module 1200 and the antenna 1100, and in the second mode, the switch 1400 operates to turn off the filter The filter F2 of the module 1200 may connect the RF integrated circuit 1500 to the antenna 1100 through the notch filter 1300 .

Referring to FIG. 9( c ), when the path of the radio frequency signal through the notch filter 1300 is not formed according to the switching operation of the switch 1400 in the first mode (Mode 1), the inherent characteristic of the filter F2 A frequency band is formed according to the upper limit frequency and the lower limit frequency. However, when the path of the radio frequency signal through the notch filter 1300 is formed according to the switching operation of the switch 1400 in the second mode (Mode 2), by the frequency characteristic of the notch filter 1300, the filter F2 As the upper limit frequency of is reduced, the bandwidth may be reduced.

FIG. 10 is a diagram provided to explain a method of changing a lower limit frequency according to an embodiment of FIG. 3 . Fig. 10(a) is a circuit diagram showing the filter F3 of Fig. 3, and Fig. 10(b) is a graph showing the change in the frequency band of the filter F3.

Referring to FIG. 10A , a filter F3 according to an embodiment of the present invention may include a plurality of resonators. Here, each of the plurality of resonators may include a volumetric acoustic resonator (FBAR).

The filter F3 may include at least one series unit 10 and at least one shunt unit 20 disposed between the at least one series unit 10 and the ground. As shown in FIG. 10 , the filter F3 may be formed in a ladder type filter structure, or alternatively, may be formed in a lattice type filter structure.

The at least one series unit 10 may be disposed between a signal input end RFin to which an input signal is input and a signal output end RFout to which an output signal is output, and the at least one shunt unit 20 includes at least one series It may be disposed between the connection node of the part 10 and the signal output terminal RFout and the ground or between the connection node of the at least one series part 10 and the signal input terminal RFin and the ground.

Although the filter F3 is illustrated as having one series part 10 and one shunt part 20 in FIG. 10(a), a plurality of series part 10 and shunt part 20 may be provided. , when a plurality of series units 10 and shunt units 20 are provided, a plurality of series units 10 are connected in series with each other, and a node between the series units 10 to which the shunt units 20 are connected in series and It can be placed between the ground. The series unit 10 may include at least one series resonator S.

The at least one shunt unit 20 may include a first shunt resonator Sh1 and a second shunt resonator Sh2. The first shunt resonator Sh1 and the second shunt resonator Sh2 may selectively operate.

The first shunt resonator Sh1 and the second shunt resonator Sh2 may be connected in parallel to each other through the first switch SW1 and the second switch SW2 . Specifically, the first shunt resonator Sh1 and the first switch SW1 may be connected to each other in series, and the second shunt resonator Sh2 and the second switch SW2 may be connected to each other in series, and in series with each other. The connected first shunt resonator Sh1 and the first switch SW1 and the second shunt resonator Sh2 and the second switch SW2 connected in series with each other may be connected in parallel. The first shunt resonator Sh1 and the second shunt resonator Sh2 connected in parallel may be connected to the ground through the trimming inductor L. Although it is illustrated as being connected to the ground through one trimming inductor L in FIG. 10A , the first shunt resonator Sh1 and the second shunt resonator Sh2 are grounded through a separate trimming inductor L. can be connected with

The first switch SW1 and the second switch SW2 may perform switching operations in different modes. For example, in the first mode (Mode 1), the first switch SW1 is turned on, and the second switch SW2 is turned off, so that in the second mode (Mode 2), the first switch SW1 is turned on. ) may be turned off, and the second switch SW2 may be turned on.

The first shunt resonator Sh1 and the second shunt resonator Sh2 may have different resonant frequencies and anti-resonant frequencies, for example, of the first shunt resonator Sh1 operating in the first mode (Mode 1). The anti-resonant frequency may be higher than the anti-resonant frequency of the second shunt resonator Sh2.

Therefore, referring to FIG. 10(b), in the first mode (Mode 1), the lower limit frequency is increased by the first shunt resonator Sh1, so that the bandwidth can be reduced, and in the second mode (Mode 2), As in the second mode (Mode 2) of FIG. 8(b) by the second series resonator S2, the lower limit frequency may be reduced, and thus the bandwidth may be expanded.

11 is a diagram provided to explain a method of changing a lower limit frequency according to another embodiment of FIG. 3 .

11 (a) is a circuit diagram illustrating a filter F3 according to an embodiment of the present invention, and FIG. 11 (b) is a graph provided to explain a change in the frequency band of the filter F3 according to an embodiment of the present invention. .

The filter F3 according to an embodiment of the present invention may include a plurality of resonators. Here, each of the plurality of resonators may include a volumetric acoustic resonator (FBAR).

The filter F3 may include at least one series unit 10 and at least one shunt unit 20 disposed between the at least one series unit 10 and the ground. As shown in 11(a), the filter F2 may be formed in a ladder type filter structure. Alternatively, the filter F2 may be formed in a lattice type filter structure.

The at least one series unit 10 may be disposed between a signal input end RFin to which an input signal is input and a signal output end RFout to which an output signal is output, and the at least one shunt unit 20 includes at least one series It may be disposed between the connection node of the part 10 and the signal output terminal RFout and the ground or between the connection node of the at least one series part 10 and the signal input terminal RFin and the ground.

Although the filter F3 is illustrated as having one series part 10 and one shunt part 20 in FIG. 10(a), a plurality of series part 10 and shunt part 20 may be provided. , when a plurality of series units 10 and shunt units 20 are provided, a plurality of series units 10 are connected in series with each other, and a node between the series units 10 to which the shunt units 20 are connected in series and It can be placed between the ground. The series unit 10 may include at least one series resonator S.

The shunt unit 20 may include a shunt resonator Sh and a transistor Tr disposed between the shunt resonator Sh and the ground, and additionally a trimming disposed between the shunt resonator Sh and the transistor Tr It may further include an inductor (L).

The transistor Tr may be implemented by at least one of an N-channel field effect transistor and a P-channel field effect transistor. The transistor Tr may be turned on and off by the gate voltage Vg applied to the gate. Specifically, the transistor Tr may operate to be turned off in the first mode Mode 1 and may operate to be turned on in the second mode Mode 2 . The transistor Tr may be equivalent to a resistor in a turned-on state and may be equivalent to a capacitor in a turned-off state.

The anti-resonant frequency of the shunt unit 20 may be changed according to the turn-on and turn-off operations of the transistor Tr. Referring to FIG. 11B , when the transistor Tr is turned off in the first mode (Mode 1), the total capacitance of the shunt unit 20 is lowered according to the capacitance of the transistor Tr, so that the shunt unit The anti-resonant frequency of (20) increases. In addition, when the transistor Tr is turned on in the second mode (Mode 2), the total capacitance of the shunt unit 20 increases, so that the anti-resonant frequency of the shunt unit 20 decreases.

Accordingly, when the transistor Tr is turned off in the first mode (Mode), the lower limit frequency of the filter F3 increases, so that the bandwidth can be reduced, and when the transistor (Tr) is turned on in the second mode (Mode), The lower limit frequency of the filter F3 is reduced, so that the bandwidth can be expanded.

12 is a diagram provided to explain a method of changing a lower limit frequency according to another embodiment of FIG. 3 .

12A and 12B are circuit diagrams illustrating a front-end module according to an embodiment of the present invention.

12A and 12B , the front end module 1000 according to an embodiment of the present invention includes an antenna 1100 , a filter module 1200 , and a notch filter 1300 . , a switch 1400 and an RF integrated circuit (IC) 1500 . The plurality of filters F1 , F2 , F3 , and F4 of the filter module 1200 may correspond to the filter module of FIG. 3 . The plurality of filters F1 , F2 , F3 , and F4 of the filter module 1200 and the notch filter 1300 may be manufactured as a volumetric acoustic resonator (FBAR). In this case, the notch filter 1300 is the filter module 1200 . ) and the switch 1400 disposed between the notch filter 1300 and the one-chip may be formed.

The antenna 1100 may transmit/receive a radio frequency signal, and the filter module 1200 may transmit and receive a radio frequency signal received through the antenna 1100 or a radio frequency signal transmitted/received through the RF integrated circuit 1500 of a specific frequency band. Filtering operations to pass and remove components can be performed. The filter module 1200 may correspond to the filter module of FIG. 3 and may include a plurality of filters F1, F2, F3, and F4.

The filter F3 of the filter module 1200 may be selectively connected to the notch filter 1300 according to a mode. The notch filter 1300 is connected between the signal path of the filter F3 and the ground to selectively operate. The notch filter 1300 may be disposed between the filter module 1200 and the RF integrated circuit 1500 , or disposed between the filter module 1200 and the antenna 1100 , and may be selectively connected to the filter F3 according to a mode.

Referring to FIG. 12A , a notch filter 1300 and a switch 1400 may be disposed between the filter module 1200 and the RF integrated circuit 1500 . Here, the notch filter 1300 may be connected to the ground so that a ground potential may be provided to the notch filter 1300 . The switch 1400 is a three-terminal switch having a first terminal connected to the filter module 1200 , a second terminal connected to the RF integrated circuit 1500 , and a third terminal connected to the notch filter 1300 . can The first terminal of the switch 1400 is connected to one of the second terminal and the third terminal to connect the filter module 1200 and the RF integrated circuit 1500 , or the filter module 1200 and the notch filter 1300 . can connect

In the first mode, the switch 1400 may connect the filter F3 of the filter module 1200 and the RF integrated circuit 1500 through the notch filter 1300, and in the second mode, the switch 1400 is the filter module ( Filter F3 of 1200 and RF integrated circuit 1500 may be directly connected.

Referring to FIG. 12B , a notch filter 1300 and a switch 1400 may be disposed between the filter module 1200 and the antenna 1100 . The switch 1400 may be connected to a connection node between the filter F3 of the filter module 1200 and the antenna 1100 , and the notch filter 1300 may be disposed between the switch 1400 and the ground.

In the first mode, the switch 1400 is turned on to connect the connection node of the filter F3 of the filter module 1200 and the antenna 1100 to the notch filter 1400, and in the second mode, the switch 1400 is turned off, so that the antenna 1100 and the filter F3 of the filter module 1200 may be directly connected.

12 (a) and 12 (b), when the path of the radio frequency signal through the notch filter 1300 is not formed according to the switching operation of the switch 1400 in the second mode, the filter F3 A frequency band is formed according to the upper limit frequency and the lower limit frequency. However, when the path of the radio frequency signal through the notch filter 1300 is formed according to the switching operation of the switch 1400 in the first mode, by the frequency characteristic of the notch filter 1300, the lower limit frequency of the filter F3 is increased, the bandwidth may decrease.

13 is a schematic diagram provided to explain a connection method between a filter module and a switch according to an example.

As described above, the filter module and the front-end module are provided with at least one switch and transistor. However, as shown in FIG. 13 , a filter module and a switch are mounted on a printed circuit board (PCB), and mutually through a wiring line provided on the printed circuit board (PCB). When connected, signal loss is induced by a parasitic component generated in a wiring line, and miniaturization is easily restricted by an area occupied by a switch in a printed circuit board (PCB).

The filter module and the front-end module according to an embodiment of the present invention integrate the filter module and the switch to minimize the wiring line between the filter module and the switch. can do. Accordingly, it is possible to reduce signal loss caused by parasitic components caused by wiring lines, and to reduce the area occupied by the switch in the external substrate to achieve miniaturization of the module.

14 is a cross-sectional view illustrating a filter according to an embodiment of the present invention.

Referring to FIG. 14 , a filter according to an embodiment of the present invention may include a plurality of volumetric acoustic resonators 100 and a cap 200 . The volumetric acoustic resonator 100 may be a thin film volumetric acoustic resonator (FBAR).

The volume acoustic resonator 100 may be implemented by a stacked structure composed of a plurality of films. In FIG. 14 , two volume acoustic resonators 100 are illustrated as being implemented by the stacked structure, but three or more volumetric acoustic resonators 100 may be implemented by the stacked structure according to design. The adjacent volume acoustic resonators 100 may be electrically connected to each other by wire electrodes. For example, the wiring electrode may connect the first electrodes 140 of the adjacent volumetric acoustic resonators 100 to each other and the second electrodes 160 of the adjacent volumetric acoustic resonators 100 to each other.

The volume acoustic resonator 100 may include a substrate 110 , an insulating layer 120 , an air cavity 112 , and a resonator 135 .

The substrate 110 may be formed of a silicon substrate, and an insulating layer 120 electrically insulating the resonator 135 from the substrate 110 may be provided on the upper surface of the substrate 110 . Insulating layer 120 is silicon dioxide (SiO2) and aluminum oxide (Al2O2) by chemical vapor deposition (Chemical vapor deposition), RF magnetron sputtering (RF Magnetron Sputtering), or evaporation (Evaporation) to the substrate 110 may be formed on the

An air cavity 112 may be disposed on the insulating layer 120 . The air cavity 112 may be located under the resonator 135 so that the resonator 135 vibrates in a predetermined direction. The air cavity 112 is formed by forming a sacrificial layer pattern on the insulating layer 120 , then forming the membrane 130 on the sacrificial layer pattern, and then removing the sacrificial layer pattern by etching. The membrane 130 may function as an oxidation protective layer or as a protective layer to protect the substrate 110 .

An etch stop layer 125 may be additionally formed between the insulating layer 120 and the air cavity 112 . The etch stop layer 125 serves to protect the substrate 110 and the insulating layer 120 from an etching process, and may serve as a base for depositing other various layers on the etch stop layer 125 .

The resonator 135 may include a first electrode 140 , a piezoelectric layer 150 , and a second electrode 160 sequentially stacked on the membrane 130 . A common region overlapping the first electrode 140 , the piezoelectric layer 150 , and the second electrode 160 in a vertical direction may be located above the air cavity 112 . The first electrode 140 and the second electrode 160 may include gold (Au), titanium (Ti), tantalum (Ta), molybdenum (Mo), ruthenium (Ru), platinum (Pt), tungsten (W), and aluminum. It may be formed of one of (Al), iridium (Ir), and nickel (Ni) or an alloy thereof.

The piezoelectric layer 150 is a part that produces a piezoelectric effect that converts electrical energy into mechanical energy in the form of acoustic waves, and may be formed of one of aluminum nitride (AlN), zinc oxide (ZnO), and lead zirconium titanium oxide (PZT; PbZrTiO). can In addition, the piezoelectric layer 150 may further include a rare earth metal. For example, the rare earth metal may include at least one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La).

A seed layer for improving the crystal orientation of the piezoelectric layer 150 may be additionally disposed under the first electrode 140 . The seed layer may be formed of one of aluminum nitride (AlN), zinc oxide (ZnO), and lead zirconium titanium oxide (PZT; PbZrTiO) having the same crystallinity as that of the piezoelectric layer 150 .

The resonator 135 may be divided into an active region and an inactive region. The active region of the resonator 135 vibrates in a predetermined direction due to a piezoelectric phenomenon occurring in the piezoelectric layer 150 when electrical energy such as a radio frequency signal is applied to the first electrode 140 and the second electrode 160 . The resonance region corresponds to a region in which the first electrode 140 , the piezoelectric layer 150 , and the second electrode 160 vertically overlap on the air cavity 112 . The inactive region of the resonator 135 is a region that does not resonate due to the piezoelectric phenomenon even when electric energy is applied to the first electrode 140 and the second electrode 160 , and corresponds to a region outside the active region.

The resonator 135 outputs a radio frequency signal having a specific frequency by using the piezoelectric phenomenon. Specifically, the resonator 135 may output a radio frequency signal having a resonant frequency corresponding to the vibration caused by the piezoelectric phenomenon of the piezoelectric layer 150 .

The protective layer 170 may be disposed on the second electrode 160 of the resonance unit 135 to prevent the second electrode 160 from being exposed to the outside. The protective layer 170 may be formed of an insulating material selected from among silicon oxide-based, silicon nitride-based, and aluminum nitride-based insulating materials.

At least one via hole 113 penetrating the substrate 110 in the thickness direction may be formed on the lower surface of the substrate 110 . The via hole 113 may pass through some of the insulating layer 120 , the etch stop layer 125 , and the membrane 130 in the thickness direction in addition to the substrate 110 . A connection pattern 114 may be formed inside the via hole 113 , and the connection pattern 114 may be formed on the inner surface of the via hole 113 , that is, the entire inner wall.

The connection pattern 114 may be manufactured by forming a conductive layer on the inner surface of the via hole 113 . For example, the connection pattern 114 may be formed by depositing or applying at least one conductive metal among gold (Au), copper (Cu), and titanium (Ti)-copper (Cu) alloy along the inner wall of the via hole 113 , or It can be formed by filling.

The connection pattern 114 may be connected to at least one of the first electrode 140 and the second electrode 160 . For example, the connection pattern 114 penetrates at least a portion of the substrate 110 , the membrane 130 , the first electrode 140 , and the piezoelectric layer 150 , and the first electrode 140 and the second electrode 160 . may be electrically connected to at least one of The connection pattern 114 formed on the inner surface of the via hole 113 may extend toward the lower surface of the substrate 110 to be connected to the connection pad 115 provided on the lower surface of the substrate 110 . Accordingly, the connection pattern 114 may electrically connect the first electrode 140 and the second electrode 160 to the connection pad 115 . For example, the connection pad 115 may include copper (Cu).

The connection pad 115 may be electrically connected to a main board that may be disposed under the filter through bumps. The volumetric acoustic resonator 100 may filter the radio frequency signal by signals applied to the first and second electrodes 110 and 120 from the main board through the connection pad 115 . The filter connected to the main board may form a filter module.

The cap 200 may be bonded to the stacked structure forming the plurality of volumetric acoustic resonators 100 to protect the plurality of volumetric acoustic resonators 100 from external environments. The cap 200 may be packaged at the stacked structure and wafer level.

The cap 200 may be formed in the form of a cover having an internal space in which the plurality of volumetric acoustic resonators 100 are accommodated. The cap 200 may be formed in a hexahedral shape with an open lower surface, and thus may include an upper surface and a plurality of side surfaces.

Specifically, the cap 200 may have a receiving portion formed in the center to accommodate the resonator portions 135 of the plurality of volumetric acoustic resonators 100 , and the rim may be joined to the bonding region of the stacked structure to be bonded to the receiving portion. It may be formed to be stepped compared to . The bonding area of the laminate structure may correspond to an edge of the laminate structure.

Referring to FIG. 14 , the cap 200 is shown to be bonded to the protective layer 170 stacked on the substrate 110 , but unlike the protective layer 170 , the membrane 130 and the etch stop layer ( 125 ), the insulating layer 120 , and the substrate 110 may be bonded to each other.

The cap 200 may be bonded to the laminate structure by eutectic bonding. After the bonding agent 250 capable of eutectic bonding is deposited on the laminated structure, the laminated structure and the cap 200 may be pressed and heated to bond them.

The bonding agent 250 is composed of at least one bonding layer, and may perform eutectic bonding between the laminate structure and the cap 200 . The bonding agent 250 may be provided in a bonding area between the stacked structure and the cap 200 .

The bonding agent 250 may include at least three bonding layers sequentially stacked between the laminate structure and the cap 200 . For example, the bonding agent 250 may include a first bonding layer 251 , a second bonding layer 252 , and a third bonding layer 253 . The first bonding layer 251 may include one of gold (Au), copper (Cu), silver (Ag), platinum (Pt), nickel (Ni), and palladium (Pd), and the second bonding layer 252 may include tin (Sn), and the third bonding layer 253 may include gold (Au), copper (Cu), silver (Ag), platinum (Pt), nickel (Ni), and palladium ( Pd) may be included. The first bonding layer 251 and the third bonding layer 253 may be formed of the same material to enable eutectic bonding together with the second bonding layer 252 .

At least one switch 300 may be provided on the outer upper surface of the cap 200 . The switch 300 of FIG. 14 is a switch shown in FIGS. 8(a), 9(a)(b), 10(a), 12(a)(b), and FIG. 11(a). It may correspond to a transistor. The switch 300 may be formed on the upper surface of the cap 200 through a complementary metal-oxide semiconductor (CMOS) process. The switch 300 may be formed on the cap 200 before or after bonding the cap 200 and the stacked structure.

A connection electrode 210 for providing an electrical connection path for the switch 300 and a connection pad 220 for the cap may be formed in the cap 200 . The cap 200 may include at least one connection electrode 210 , and the at least one connection electrode 210 may be formed substantially vertically through the upper portion of the cap 200 in the thickness direction.

The connection pad 220 for the cap is provided along the upper surface of the cap 200 and can be connected to the switch 300 exposed to the upper portion of the cap 200 , and at least one connection electrode 210 is provided along the upper surface of the cap 200 . It can be connected to the switch 300 through the connection pad 220 for the cap extending along the outer surface.

At least one connection electrode 210 may extend from an upper portion of the cap 200 to be connected to at least one of the first electrode 140 and the second electrode 160 . Although the connection electrode 210 is illustrated as being connected to the first electrode 140 and the second electrode 160 in FIG. 14 , the connection electrode 210 is connected to the first electrode 140 and the second electrode 160 . It may be directly connected to the connection pattern 114 electrically connected to the first electrode 140 and the second electrode 160 by passing therethrough.

The switching operation of the switch 300 may be controlled by a signal applied from the main substrate under the filter module through the connection pattern 114 and the connection pad 115 for the substrate.

According to an embodiment of the present invention, since the switch 300 can operate from the main board disposed below in a state adjacent to the filter, a complex circuit pattern long provided on the main board for connection between the conventional switch and the filter module is formed. By avoiding this, it is possible to reduce the signal loss caused by the parasitic component and increase the board area efficiency compared to the component.

In the above, the present invention has been described with specific matters such as specific components and limited embodiments and drawings, but these are provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments. , those of ordinary skill in the art to which the present invention pertains can devise various modifications and variations from these descriptions.

The present invention is not limited by the above-described embodiments and the accompanying drawings, but is intended to be limited by the appended claims. Therefore, various types of substitution, modification and change will be possible by those skilled in the art within the scope not departing from the technical spirit of the present invention described in the claims, and it is also said that it falls within the scope of the present invention. something to do.

10: series part
20: shunt unit
100: volumetric acoustic resonator
113: via hole
114: connection pattern
115: connection pad
135: resonance unit
140: first electrode
150: piezoelectric layer
160: second electrode
210: connection electrode
220: connection pad for cap
300: switch
1000: front-end module
1100: antenna
1200: filter module
1300: notch filter
1400: switch
1500: RF integrated circuit

Claims (14)

a plurality of volumetric acoustic resonators comprising at least one series resonator and at least one shunt resonator formed by a substrate, a first electrode sequentially stacked on the substrate, a piezoelectric layer, and a second electrode;
a cap accommodating the plurality of volumetric acoustic resonators and spaced apart from the plurality of volumetric acoustic resonators;
at least one switch provided on the cap; and
a connection electrode penetrating an upper portion of the cap in a thickness direction to electrically connect at least one of the first electrode and the second electrode to the switch; filter containing .
According to claim 1,
one of the at least one series resonator and the at least one shunt resonator is coupled to the switch.
3. The method of claim 2,
A resonator connected to the switch selectively operates according to a switching operation of the switch.
4. The method of claim 3,
A filter in which a frequency band supported by the resonator connected to the switch is variable according to a switching operation of the switch.
5. The method of claim 4,
A filter in which an upper limit frequency of the frequency band is varied according to a selective operation of at least one series resonator connected to the switch.
5. The method of claim 4,
A filter in which a lower limit frequency of the frequency band is varied according to a selective operation of at least one shunt resonator connected to the switch.
According to claim 1,
The switch is a filter provided on the upper surface of the cap through a complementary metal-oxide semiconductor (CMOS) process.
The method of claim 7, wherein the cap comprises:
and a connection pad for a cap extending along an upper surface of the cap and connecting to the switch and the connection electrode.
9. The method of claim 8,
The switch is a filter in which a switching operation is controlled according to a signal applied through the connection pad for the cap.
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