FBAR band pass filter, Duplexer having the FBAR band pass filter and Methods for manufacturing the same

FBAR band pass filter, Duplexer having the FBAR band pass filter and Methods for manufacturing the same

1 is a schematic block diagram of a conventional duplexer.

2 is a schematic cross-sectional view of a conventional FBAR filter.

3 is a cross-sectional view of a conventional FBAR duplexer.

4 is a cross-sectional view for explaining the configuration of a band pass filter including an FBAR according to an embodiment of the present invention.

5A to 5I are cross-sectional views illustrating a manufacturing process of the band pass filter shown in FIG. 4 .

6 is a plan view of a transmitter band pass filter including a plurality of FBARs and an inductor according to another embodiment of the present invention.

7 is a plan view of a receiver band-pass filter including a plurality of FBARs and an inductor according to another embodiment of the present invention.

8 is a plan view of a duplexer composed of a receiver and a transmitter band-pass filter each including a plurality of FBARs and inductors according to another embodiment of the present invention.

8 is a plan view of a duplexer including the receiver and transmitter bandpass filters shown in FIGS. 6 and 7 according to another embodiment of the present invention.

9 and 10 are conceptual diagrams for explaining the configuration of a transmitter and a receiver band pass filter according to another embodiment of the present invention, respectively.

11 is a conceptual diagram illustrating a configuration of a duplexer according to another embodiment of the present invention.

<Explanation of symbols for main parts of the drawing>

200, 605, 610: band pass filter 205, 355, 405, 460: substrate

210: insulating film 215: membrane

220: FBAR 225: first lower electrode

230: piezoelectric layer 235: first upper electrode

240: first cavity 245: second cavity

250: Inductor 255: Metal wiring

260: Connection wiring 270, 630: Capacitor

275: second lower electrode 280: dielectric layer

285: second upper electrode 290: air gap

300: first recess 305: second recess

310: sacrificial film 315: sacrificial film pattern

320: first buried layer 325: second buried layer

350, 500: Transmitter band pass filter 400, 550: Receiver band pass filter

450, 600: Duplexer 361, 411, 511, 561: First FBAR

362, 412, 512, 562: Second FBAR 363, 413, 513, 563: Third FBAR

364, 414, 514, 564: Fourth FBAR 365, 415, 515, 565: Fifth FBAR

366, 516: 6th FBAR 371, 421, 521, 571, 615: 1st inductor

372, 422, 522, 572, 620: Second inductor

423, 424, 425: third to fifth inductors

<backgroundart><p>The present invention relates to a FBAR (Film Bulk Acoustic Resonator) band pass filter, a duplexer having the same, and a manufacturing method thereof, and more particularly, to be easily implemented on a single chip by applying MEMS (Micro Electro-Mechanical System) technology. It relates to a possible FBAR band pass filter, a duplexer including the same, and a method of manufacturing the same.</p><p>In general, a duplexer refers to a device that separates and transmits a transmission frequency and a reception frequency among various radio signals of a mobile communication device, and selects only a necessary frequency from among many radio signals mixed with noise. That is, the duplexer is generally connected to the lower end of the antenna of the mobile communication device to separate transmission and reception frequencies, and performs a function of passing only necessary signals during transmission and reception and removing unnecessary signals. In recent years, as high-performance and miniaturization of mobile communication devices have become a trend, multi-mode, which can cover dual-band or triple-band, or any method, is rapidly progressing. Currently, as a duplexer, a SAW duplexer is widely used in accordance with the trend of reduction in weight and thickness of mobile communication devices.</p><p>The SAW duplexer is disclosed in US Pat. No. 6,313,715 to Andreas Bergmann et al.</p><p>1 shows a schematic block diagram of the SAW duplexer disclosed in the above US patent.</p><p>Referring to FIG. 1 , the SAW duplexer 10 includes a transmit (Tx) SAW filter 15 , a receive (Rx) SAW filter 20 , a transmit capacitor 25 , and an inductor 35 . Capacitor 25 is connected in series to transmit SAW filter 15 , but may also be connected to receive SAW filter 20 , and inductor 35 is generally connected in parallel to a signal line branching from antenna 30 .</p><p>The SAW duplexer 10 having the above configuration transmits a signal transmitted from the system to the antenna 30 through the transmission SAW filter 15 according to the frequency of the received signal, or receives a signal received from the antenna 30 . It performs the function of transmitting to the system through the SAW filter (20). </p><p>The transmitting and receiving SAW filters 15 and 20 have a structure in which one or more electrodes are formed on a substrate made of a piezoelectric material as disclosed in U.S. Patent No. 6,297,580 to Ryouichi Takayama et al., and these SAW filters ( 15, 20) have been widely used in recent years because of their small size and light weight.</p><p>Currently, widely used CDMA (Code Division Multiple Access) terminals or data cards are essentially provided with a duplexer that separates transmission and reception signals from one antenna. A duplexer used in a mobile communication device includes a SAW band pass filter packaged using an expensive ceramic package. </p><p>However, when the SAW band pass filter is employed, the size of the duplexer inevitably increases, making it difficult to arrange all components on one chip, which is a major obstacle to high performance and miniaturization of mobile communication devices in the future. For example, in the case of a currently used Personal Communication Service (PCS) terminal, a duplexer including two SAW filters having a frequency band of about 1850 to 1880 MHz and about 1880 to 1910 MHz, respectively, is used. Since a substrate having an area of at least about 5×12 mm is required for this purpose, it is a big obstacle to miniaturization of mobile communication devices.</p><p>In addition, in the case of the duplexer employing the SAW filter, the chip size is increased, and the manufacturing cost of the SAW duplexer is greatly increased because the ceramic for the package is expensive. Furthermore, since packaging with the SAW filter up to an Impedance Matching Network (IMN) that does not require packaging in a ceramic package, the manufacturing process of the SAW duplexer becomes difficult and manufacturing cost increases.</p><p>In contrast, the FBAR filter can be mass-produced at a low cost, and the size of the board on which the duplexer including the FBAR filter is formed can be reduced to about 3×3 mm or less. In addition, since the FBAR filter can be used in the micro frequency band, it has the advantage that it can be used not only in the PCS frequency band but also in the DCS (Digital Cellular System) frequency band. . The FBAR uses the principle that, when electric energy is applied to both electrodes interposed between the piezoelectric body, an electric field that changes with time is maintained in the piezoelectric layer, and a bulk acoustic wave is generated according to the electric field.</p><p>2 is a schematic cross-sectional view of a conventional FBAR filter.</p><p>Referring to FIG. 2 , the conventional FBAR filter 50 has a structure in which a lower electrode layer 60 , a piezoelectric layer 65 , and an upper electrode layer 70 are sequentially stacked on a semiconductor substrate 55 .</p><p>In the FBAR filter 50, the piezoelectric layer 65 is formed by stacking a piezoelectric material such as zinc oxide (ZnO) or aluminum nitride (AlN) by a sputtering method, thereby inducing resonance due to the piezoelectric properties of the piezoelectric layer 65 . A thin-film structure device is implemented as a filter.</p><p>Meanwhile, US Patent No. 6,407,649 issued to Pasi Tikka et al. discloses a duplexer having an FBAR band pass filter.</p><p>3 is a cross-sectional view of a duplexer including the FBAR band pass filter disclosed in the US patent.</p><p>As shown in FIG. 3 , the conventional FBAR duplexer 100 includes a reception filter 130 and a transmission filter 135 formed on a substrate 105 . The transmit and receive filters 130 and 135 include serial resonators 110 and 115 and shunt resonators 120 and 125, respectively. The serial and shunt resonators 110 , 115 , 120 and 125 each include a lower electrode 145 , a piezoelectric layer 150 , and an upper electrode 155 , and a lower structure 140 including an inductor or a capacitor. formed on the In this case, shunt tuners 155 and 160 may be additionally formed on the upper electrode 155 of each of the shunt resonators 120 and 125 , and the serial and shunt resonators 115 and 125 of the transmission filter 135 . A transmission tuning layer 165 may be further formed on the upper electrode 155 of the shunt tuner 160 and the shunt tuner 160 .</p><p>However, in the duplexer disclosed in the US patent, since the transmit FBAR filter, the receive FBAR filter, and the chip-type inductor are each manufactured in a single element method, and then packaged on a substrate to manufacture the duplexer module, the size of the duplex module There is a limit to reducing In addition, there is a problem in that the manufacturing time and manufacturing cost of the duplexer increases because the transmit and receive FBAR filters, and components such as an inductor and a capacitor are separately manufactured and integrated.</p></backgroundart><abstractproblem><p>Accordingly, an object of the present invention is to provide a duplexer having an FBAR bandpass filter that can be manufactured inexpensively while reducing the size of a module by easily implementing a page shifter, an inductor, and an FBAR filter on one substrate. will be.</p><p>Another object of the present invention is to easily implement a page shifter, an inductor, and an FBAR filter on a single substrate, thereby reducing the size of the module and manufacturing a duplexer having an FBAR band-pass filter that can be manufactured inexpensively. To provide a manufacturing method.</p><p>Another object of the present invention is to provide a transmit or receive FBAR band pass filter that can be implemented integrally with an inductor on a single substrate or implemented separately from them.</p><p>Another object of the present invention is to provide a method of manufacturing an FBAR band-pass filter that is particularly suitable for a transmit or receive FBAR band-pass filter that can be implemented integrally with an inductor on a single substrate or implemented separately from them. </p></abstractproblem>

<p>According to preferred embodiments of the present invention in order to achieve the above object of the present invention, at least two FBARs formed on one side of the upper portion of the substrate and electrically connected to each other A transmitter band pass filter having at least one inductor, a receiver band-pass filter formed on the other upper portion of the substrate and having at least two FBARs and at least one inductor electrically connected to each other, and formed on the substrate between the transmitter and the receiver band-pass filter, the transmitter and A duplexer including a page shifter electrically connected to a receiver band pass filter is provided. The FBAR has a lower electrode, a piezoelectric layer and an upper electrode, respectively, wherein the lower electrode and the upper electrode are selected from the group consisting of aluminum, gold, platinum, tungsten, molybdenum, tantalum, platinum-tantalum, titanium and platinum-titanium. The piezoelectric layer includes any one selected from the group consisting of PZT, PLZT, PMN, PMN-PT, PZN, PZN-PT, aluminum nitride, and zinc oxide. The page shifter may include an inductor and a capacitor.</p><p>According to the present invention in order to achieve the other object of the present invention, forming a plurality of recesses on a substrate, forming an insulating film on the substrate, forming a plurality of buried layers filling the recesses Step, forming a membrane on the buried layer and the substrate; Forming a receiver band pass filter having at least two FBARs and at least one inductor electrically connected to each other on the other upper side of the and removing the buried layer is provided.</p><p>In addition, according to the present invention in order to achieve another object of the present invention described above, a substrate, at least two FBARs formed on one side of the substrate, and the other side of the substrate are formed on the upper portion of the substrate and electrically connected to the FBARs An FBAR band pass filter comprising at least one inductor is provided. In this case, at least one cavity is provided between each FBAR and one side of the substrate, and the FBAR includes a lower electrode, a piezoelectric layer formed on the lower electrode, and an upper electrode formed on the piezoelectric layer, A first cavity is formed between a portion of the lower electrode and the substrate, and a second cavity is formed between another portion of the lower electrode and the substrate.</p><p>In addition, according to the present invention in order to achieve another object of the present invention described above, forming at least two recesses on one side of the substrate, forming an insulating film on the substrate, at least filling the recesses forming one buried layer, forming a membrane on the buried layer and the insulating film, forming at least two FBARs on one side of the membrane, and adjacent to the FBARs to the FBAR on the membrane A method of manufacturing an FBAR band pass filter is provided, comprising forming at least one electrically connected inductor. The substrate includes any one selected from the group consisting of silicon, high resistance silicon, gallium-arsenide, glass and ceramic, and the insulating film includes any one selected from the group consisting of silicon oxide, silicon nitride, zinc oxide and aluminum nitride do. The buried layer includes any one selected from the group consisting of polysilicon, phosphorus-silicate glass (PSG), zinc oxide, and a polymer, and the membrane includes any one selected from the group consisting of low-temperature oxide, silicon nitride, zinc oxide and aluminum nitride. includes</p><p>The forming of the FBAR may include forming a first lower electrode on one side of the membrane, forming a piezoelectric layer on the lower electrode, forming a first upper electrode on the piezoelectric layer, and The method may further include removing the buried layer. </p><p>In the present invention, the FBAR band-pass filter is a core component that removes noise and enhances sound quality by extracting only a specific frequency in the process of receiving a high frequency of about 1 to 15 GHz, and is manufactured using a semiconductor process. Compared to a surface acoustic wave (SAW) filter and a ceramic filter, the size may be about 1/10 to about 1/100 or more, and may be formed to be smaller and lighter. That is, since the transmission and reception bandpass filters and the inductor can be easily implemented as a single chip, it is possible to provide a duplexer having a minimum size in response to the requirements for miniaturization and weight reduction of various mobile communication devices. In addition, the transmit or receive bandpass filter according to the present invention can be implemented with a significantly smaller size than the conventional SAW bandpass filter, and has advantages such as low insertion loss and low power consumption. Accordingly, interface design and terminal operation programming can be more easily implemented, and a board area on which a duplexer is mounted in a mobile communication device can be reduced by nearly 80%. Moreover, since the duplexer including the transmit band pass filter and the receive band pass filter according to the present invention can be easily manufactured on one substrate using the MEMS process, the manufacturing cost and manufacturing time of the duplexer can be greatly reduced. can</p><p>Hereinafter, an FBAR band-pass filter, a duplexer having an FBAR band-pass filter, and a manufacturing method thereof according to preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is limited by the following embodiments is not limited or limited.</p><p>4 is a cross-sectional view illustrating a configuration of a band pass filter including an FBAR according to an embodiment of the present invention.</p><p>Referring to FIG. 4 , the transmit (Tx) or receive (Rx) FBAR band pass filter 150 according to the present embodiment includes a substrate 205 , an insulating film 210 formed on the substrate 205 , first and second A membrane 210 formed on an insulating film with a cavity interposed therebetween, an FBAR 220 formed on one side of the membrane 210, and an inductor 250 formed on the other side of the membrane 210 is provided. . That is, according to the present embodiment, the FBAR 220 , the inductor 250 , and the capacitor 270 are integrally implemented on one substrate 205 .</p><p>The substrate 210 is generally made of silicon (Si), silicon, high resistance silicon (HRS), gallium-arsenide (Ge-As), glass, or ceramic, and the insulating film 210 is silicon oxide, zinc oxide ( ZnO), silicon nitride (Si<sb>X</sb>N<sb>Y</sb>), or aluminum nitride (AlN).</p><p>First and second cavities 240 and 245 having predetermined dimensions are formed in a lower portion of the FBAR 220 positioned on one side of the substrate 210 , and first and second cavities 240 are formed in an upper portion of the insulating layer 210 . , 245 is interposed to form a membrane 215 made of silicon oxide, zinc oxide, or a nitride such as silicon nitride or aluminum nitride.</p><p>The FBAR 220 is disposed on one side of the upper portion of the membrane 215 in which the first and second cavities 240 and 245 are positioned thereunder. The FBAR 220 includes a first lower electrode 225 formed on the membrane 215 , a piezoelectric layer 230 formed on the first lower electrode 225 , and an upper electrode formed on the first upper portion of the piezoelectric layer 230 . (235).</p><p>Aluminum (Au), gold (Au), platinum (Pt), tungsten (W), molybdenum (Mo), tantalum (Ta), platinum-tantalum (Pt-Ta), titanium (Ti), or platinum-titanium (Pt) The first lower electrode 225 made of a metal having excellent electrical conductivity, such as -Ti), is divided into two parts centering on the first and second cavities 240 and 245, and one side of each has the first and second cavities. It is positioned on top of the 240 and 245 , and the other side has a structure extending onto the membrane 215 .</p><p>The piezoelectric layer 230 made of aluminum nitride (AlN) or zinc oxide (ZnO) is formed on the first lower electrode 225 with a smaller area than the lower electrode 225 . The piezoelectric layer 230 generates a volume acoustic wave when a signal is applied to the lower electrode 225 to generate an electric field that changes with time between the first lower electrode 225 and the first upper electrode 235 .</p><p>The first upper electrode 235 has a smaller area than that of the piezoelectric layer 230 and is formed on the piezoelectric layer 230, and the same as the first lower electrode 235, aluminum, gold, platinum, tungsten, molybdenum, tantalum, It is made of a metal having excellent electrical conductivity, such as platinum-tantalum, titanium, or platinum-titanium.</p><p>The capacitor 270 disposed on the other side of the membrane 215 adjacent to the inductor 250 includes a second lower electrode 275 , a dielectric layer 280 , and a second upper electrode 285 . A metal wiring 260 made of a metal having excellent electrical conductivity, such as aluminum, platinum, tantalum, platinum-tantalum, titanium, or platinum-titanium, extends from the capacitor 270 and passes through the inductor 250 of the FBAR 220 . It is connected to the first lower electrode 225 . At this time, the connection wiring 260 is connected to the metal wiring 255 of the inductor 250 in a form with an air gap 290 interposed therebetween, but the inductor 250 is embedded in the substrate 210 . may be connected to</p><p>In the present invention, the transmit or receive FBAR band pass filter 200 is composed of at least two or more FBARs 220 or two or more FBARs 220 and one or more inductors 250 . The FBAR band pass filter 200 may be composed of only the FBAR 220 , but by adding an inductor 250 thereto, appropriate attenuation may be obtained in the band for the transmitting end or the band for the receiving end. However, when there is sufficient attenuation, since the inductor 250 is not additionally required, only the FBARs 220 may constitute the band pass filter 200 .</p><p>Hereinafter, a method of manufacturing the transmit or receive band pass filter 200 according to an embodiment of the present invention will be described in detail with reference to the drawings.</p><p>5A to 5I are cross-sectional views illustrating a manufacturing process of the band pass filter shown in FIG. 4 . 5A to 5G , the same reference numerals are used for the same members as in FIG. 4 .</p><p>Referring to FIG. 5A , a substrate 200 made of a silicon or high resistance silicon (HRS) wafer, a compound semiconductor such as gallium-arsenide (Ge-As), or glass or ceramic is prepared, and then a photolithography process is performed. First and second recesses adjacent to each other on the substrate 200 to form the first and second cavities 240 and 245 by etching the upper portion of one side of the substrate 200 to a predetermined depth using ) (300, 305).</p><p>Referring to FIG. 5B, silicon oxide is deposited to a thickness of about 1000 Å to 10 μm using a chemical vapor deposition (CVD) method on the substrate 200 on which the first and second recesses 300 and 305 are formed. An insulating film 210 is formed. In addition, the insulating film 210 may be formed by depositing silicon nitride, zinc oxide, or aluminum nitride by a chemical vapor deposition method, plasma enhanced chemical vapor deposition (PECVD), or sputtering method. At this time, since the insulating film 210 is formed on the substrate 200 including the first and second recesses 300 and 305 , the insulating film 210 has the first and second recesses 300 and 305 in the insulating film 210 . Corresponding openings are formed.</p><p>Next, a sacrificial layer 310 to a thickness of about 1000 Å to 10 μm is stacked on the insulating layer 210 to form the first and second cavities 240 and 245 . The sacrificial layer 310 is formed of poly-silicon, phosphor-silicate glass (PSG), zinc oxide, or a polymer by a chemical vapor deposition (CVD) method, a sputtering method, or a spin coating method. ) to form by deposition. When the sacrificial layer 310 is made of phosphorus-silicate glass or polysilicon, the sacrificial layer 310 is formed through chemical vapor deposition (CVD). In addition, when zinc oxide is used, the sacrificial layer 310 is formed by a sputtering method, and when the sacrificial layer 310 is made of a polymer, the sacrificial layer 310 is formed by a spin coating method.</p><p>Referring to FIG. 5C , the sacrificial layer 310 is patterned so that the sacrificial layer 310 remains only on the upper portions of the first and second recesses 300 and 305 using a photolithography method, thereby forming the first and second lithography. A sacrificial layer pattern 315 is formed on the insulating layer 210 centered on the recesses 300 and 305 . In this case, the sacrificial layer pattern 315 fills the openings of the insulating layer 210 corresponding to the first and second recesses 300 and 305 of the substrate 200 .</p><p>Referring to FIG. 5D , first and second steps for filling the openings of the insulating layer 210 by polishing the sacrificial layer pattern 315 by a chemical mechanical polishing method or by etching it by an etch back method 2 The buried layers 320 and 325 are formed. Accordingly, the first recess 300 is filled with the insulating layer 210 and the first buried layer 320 , and the second recess 305 is filled with the insulating layer 210 and the second buried layer 325 . . After the first and second buried layers 320 and 325 are removed, first and second cavities 240 and 245 are formed.</p><p>Referring to FIG. 5E , a membrane 215 and a first metal layer (not shown) are sequentially formed on the first and second buried layers 320 and 325 and the insulating layer 210 . </p><p>The membrane 215 is formed to a thickness of about 1000 Å to 10 μm by depositing silicon oxide, silicon nitride, zinc oxide, or aluminum nitride by a low-pressure chemical vapor deposition method, a plasma enhanced chemical vapor deposition method, or a sputtering method. When the membrane 215 is made of silicon oxide or silicon nitride, it is formed by a low-pressure chemical vapor deposition method or a plasma enhanced chemical vapor deposition method, and when it is made of zinc oxide or aluminum nitride, it is formed by a sputtering method.</p><p>The first metal layer is formed by depositing a metal having excellent electrical conductivity, such as aluminum, gold, platinum, tungsten, molybdenum, tantalum, platinum-tantalum, titanium, or platinum-titanium, by a sputtering method or a vacuum deposition method to about 1000 Å to 10 μm. formed to a thickness of </p><p>Then, by patterning the first metal layer using a photolithography process, a first lower electrode 225 is formed on one side of the membrane 215 and a second lower electrode 275 is formed on the other side of the membrane 215 . to form The first lower electrode 225 is divided into two parts with a center between the first and second buried layers 320 and 325 . That is, a portion of the first lower electrode 225 is formed on the membrane 215 with the first buried layer 320 positioned thereunder, and the remainder of the first lower electrode 225 is formed with the second buried layer 325 thereunder. It is formed on the located membrane 215 . A portion and the rest of the first lower electrode 225 are spaced apart from each other by a predetermined distance.</p><p>Meanwhile, the second lower electrode 275 is formed on the other side of the membrane 215 . In this case, since the metal wiring 255 of the inductor 250 is subsequently formed between the first lower electrode 225 and the second lower electrode 275 , the first lower electrode 225 and the second lower electrode ( 275 are spaced apart from each other at appropriate intervals in consideration of the width of the metal wiring 255 . The first lower electrode 225 functions as a lower electrode of the FBAR 220 , and the second lower electrode 275 functions as a lower electrode of the capacitor 270 .</p><p>Referring to FIG. 5F , on the membrane 215 on which the first and second lower electrodes 225 and 275 are formed, PZT, PLZT, PMN, PMN-PT, PZN, PZN-PT, aluminum nitride, or zinc oxide. A piezoelectric dielectric is laminated to a thickness of about 1000 Å to about 10 μm using a chemical vapor deposition method, a sol-gel method, a sputtering method, or a spin coating method. </p><p>Then, the dielectric is patterned by a photolithography process to form the piezoelectric layer 230 of the FBAR 220 on the first lower electrode 225 and the dielectric layer of the capacitor 270 on the second lower electrode 275 ( 280) is formed. In this case, the piezoelectric layer 230 may be heat-treated by a rapid thermal annealing (RTA) method for a phase change of the piezoelectric material constituting the piezoelectric layer 230 .</p><p>Subsequently, a metal such as aluminum, gold, platinum, tungsten, molybdenum, tantalum, platinum-tantalum, titanium, or platinum-titanium, which is the same metal as the first lower electrode 225 , is sputtered on the piezoelectric layer 230 by a sputtering method or A second metal layer (not shown) having a thickness of about 1000 Å to 10 μm is formed by vacuum deposition, and then the second metal layer is patterned to form the first upper electrode 235 of the FBAR 220 . . Accordingly, the FBAR 220 including the first lower electrode 225 , the piezoelectric layer 230 and the first upper electrode 235 is completed.</p><p>Referring to FIG. 5G , the metal wiring 255 is formed on the membrane 215 between the FBAR 220 and the second lower electrode 275 by a lift-off or electroplating method and at the same time a dielectric layer is formed. A second upper electrode 285 is formed on the 280 . The metal wiring 255 and the second upper electrode 285 are made of a metal such as aluminum, gold, platinum, tungsten, molybdenum, tantalum, platinum-tantalum, titanium, or platinum-titanium, and each is about 1000 Å to 10 μm. formed to a thickness of In this case, the second upper electrode 285 of the capacitor 270 is formed to have a greater thickness than the first upper electrode 235 of the FBAR 220 . Accordingly, the inductor 250 including the metal wiring 255 and the capacitor 270 including the second lower electrode 275 , the dielectric layer 280 and the second upper electrode 285 are simultaneously completed. According to this embodiment, the second upper electrode 285 of the capacitor 270 is formed simultaneously with the metal wiring 255 of the inductor 250 separately from the first upper electrode 235 of the FBAR 220 . In this embodiment, since the second upper electrode 285 of the capacitor 270 is formed to have a thicker thickness than the first upper electrode 235 of the FBAR 220, the resonance of the piezoelectric layer 230 is blocked. It can function as a general capacitor 270 .</p><p>Referring to FIG. 5H , a photoresist layer is applied on the membrane 215 on which the inductor 250 is formed, and then the applied photoresist layer is patterned to form the second upper electrode 285 of the capacitor 270 and the inductor ( A photoresist pattern (not shown) partially exposing the metal line 255 of the 250 and the first lower electrode 225 of the FBAR 220 is formed. </p><p>Next, on the exposed second upper electrode 285 of the capacitor 270 , the metal line 255 of the inductor 250 , the first lower electrode 225 of the FBAR 220 and the photoresist pattern, aluminum, gold, A third metal layer (not shown) composed of a metal such as platinum, tungsten, molybdenum, tantalum, platinum-tantalum, titanium, or platinum-titanium is deposited to a thickness of about 1000 Å to 10 μm using a sputtering method or a vacuum deposition method. to form</p><p>Subsequently, the second upper electrode 285 of the capacitor 270, the metal line 255 of the inductor 250, and the first lower portion of the FBAR 220 are exposed by patterning the deposited third metal layer through a photolithography process. When the connection wiring 260 electrically connecting the electrodes 225 to each other is formed and then the photoresist pattern is removed, an air bridge or a buried connection wiring 260 is formed on the upper portion of the inductor 250 . is formed in At this time, when the photoresist pattern is removed, an air gap 290 is formed at a position of the photoresist pattern. Accordingly, the capacitor 270 , the inductor 250 , and the FBAR 220 of the page shifter are electrically connected through the connection line 260 .</p><p>5I, by removing the first and second buried layers 320 and 325 under the membrane 215 to form first and second cavities 240 and 245 under the FBAR 220, the FBAR ( 220), the inductor 250, and the capacitor 270 to complete the transmit or receive band pass filter 200. In this case, when the first and second buried layers 320 and 325 are made of polysilicon, xenon fluoride (XeF)<sb>2</sb>) or bromine fluoride (BrF<sb>2</sb>), and when the first and second buried layers 320 and 325 are made of phosphorus-silicate glass or zinc oxide, they are removed using Buffered Oxide Etchant (BOE) or hydrogen fluoride (HF). In addition, when the first and second buried layers 320 and 325 are made of a polymer, they are removed using an ashing process or an organic solvent containing acetone.</p><p>6 is a plan view of a transmitter band pass filter including a plurality of FBARs and an inductor according to another embodiment of the present invention.</p><p>Referring to FIG. 6 , the transmitter band pass filter 350 of the duplexer according to the present embodiment is formed on a substrate 355 and electrically connected to each other first to sixth FBARs 361 , 362 , 363 , 364 , 365 , 366) and first and second inductors 371 and 372. That is, according to the present embodiment, one transmitter band-pass filter 350 is configured by connecting a plurality of FBARs to each other. The first to sixth FBARs 361 , 362 , 363 , 364 , 365 and 366 are electrically connected in such a way that their lower electrodes are in contact with each other, respectively, or the first to sixth FBARs 361 , 362 , 363 , 364 . , 365 and 366) are electrically connected to each other through separate metal wires respectively formed between them.</p><p>In the present invention, the transmitter or receiver band pass filter of the duplexer may be basically composed of two FBARs. For example, by connecting one serial FBAR and one shunt FBAR, a band pass filter can be configured. In this case, the serial FBAR and the shunt FBAR must have different resonant frequencies. A difference in resonant frequency between these FBARs appears as a frequency band of the band pass filter. That is, the band-pass filter can be configured by basically combining two FBARs, but depending on the requirements of a mobile communication device equipped with a duplexer including such a band-pass filter, a larger number of FBARs can be combined in various forms. can</p><p>Referring back to FIG. 6 , the first FBAR 361 is electrically connected to the first inductor 371 through a first metal wire 381 , and the second metal wire 382 is connected to the sixth FBAR 366 . and the second inductor 372 are electrically connected. The first and second inductors 371 and 372 perform a function of increasing the attenuation in the frequency band required according to the mobile communication device because the attenuation in the frequency band of the reception part of the duplexer is very small in the transmitter band pass filter 350. do.</p><p>In this embodiment, the transmission unit band-pass filter 350 having the first to sixth FBARs 361, 362, 363, 364, 365, 366 and the first and second inductors 371 and 372 is manufactured. The method is the same as the manufacturing process of the band-pass filter according to FIGS. 5A to 5I except for the difference in the patterning shape in the photolithography process, and thus a description thereof will be omitted. </p><p>7 is a plan view of a receiver band-pass filter including a plurality of FBARs and an inductor according to another embodiment of the present invention.</p><p>Referring to FIG. 7 , first to fifth FBARs 411 , 412 , 413 , 414 , and 415 are formed on a substrate 405 and electrically connected to each other in the receiving unit band pass filter 400 of the duplexer according to the present embodiment. and first to fifth inductors 421 , 422 , 423 , 424 , and 425 . The first to fifth FBARs 411 , 412 , 413 , 414 , and 415 are electrically connected to each other through first to fifth metal wirings 431 , 432 , 433 , 434 , and 435 , respectively.</p><p>8 is a plan view of a duplexer including the receiver and transmitter bandpass filters shown in FIGS. 6 and 7 according to another embodiment of the present invention. In FIG. 8 , the same reference numerals are used for the same members as in FIGS. 6 and 7 .</p><p>In the present invention, the duplexer 450 is composed of two or more FBAR band pass filters 350, and these transmit and receive FBAR band pass filters 350 are connected to an antenna to form a duplexer. A page shifter 595 having an inductor and a capacitor is required to connect the transmit and receive bandpass filters to the antenna. In this case, the page shifter 595 serves to cancel mutual interference between the transmitting end bandpass filter and the receiving end bandpass filter 350 . In general, the page shifter 595 may be configured using a λ/4 transmission line or an LC circuit. However, since the length of the λ/4 transmission line is too long, in the present invention, the page shifter 595 is configured using an LC circuit including an inductor 591 and a capacitor 593 in order to reduce the size of the device.</p><p>Referring to FIG. 8 , the duplexer 450 includes a transmitter band pass filter 350 formed on one side of the substrate 460 and a receiver band pass filter 400 formed on the other side of the substrate 460 . The transmitter band pass filter 350 is formed on the substrate 460 and is electrically connected to the first to sixth FBARs 361 , 362 , 363 , 364 , 365 and 366 and the first and second inductors 371 and 372 . ), and the receiver band pass filter 400 includes the first to fifth FBARs 411 , 412 , 413 , 414 , 415 , wherein the receiver band pass filter 400 is formed on the substrate 405 and electrically connected to each other. and first to fifth inductors 421 , 422 , 423 , 424 , and 425 .</p><p>In the present invention, in order to configure the duplexer 450, FBARs having at least four different resonant frequencies are required. In the present invention, a loading effect is used so that each FBAR constituting the duplexer 450 has a different resonant frequency. This loading effect is usually obtained by changing the inductance on the equivalent circuit of the RLC, and thus the resonant frequency of the single FBAR resonator changes. At this time, since the inductance is changed according to the mass of the FBAR, a metal having excellent electrical conductivity may be formed on the substrate 460 while controlling the inductance of the equivalent circuit by a lift-off or electroplating method.</p><p>9 and 10 are conceptual diagrams for explaining the configuration of a transmitter and a receiver band pass filter according to another embodiment of the present invention, respectively.</p><p>9 and 10 , the transmitter band pass filter 500 includes first to fourth FBARs 511 , 512 , 513 , and 514 , first and second FBARs 511 , 512 , 513 , and 514 arranged in parallel with each other on a substrate. A fifth FBAR 515 disposed in a direction orthogonal to the first and second FBARs 511 and 512 between 511 and 512, disposed in a direction orthogonal between the third and fourth FBARs 513 and 514 a sixth FBAR 516 , a first inductor 521 formed adjacent to the fifth FBAR 515 , and a second inductor 522 disposed adjacent to the sixth FBAR 516 . At this time, the first to sixth FBARs 511 , 512 , 513 , 514 , and 515 are electrically connected to each other, and the fifth and sixth FBARs 515 and 516 and the first and second inductors 521 and 522 . are electrically connected to each other through metal wires, respectively.</p><p>On the other hand, the receiver band pass filter 550 is disposed in a direction orthogonal between the first to third FBARs 561 , 562 , 563 and the first and second FBARs 561 and 562 arranged in parallel with each other on the substrate. A fourth FBAR 564 disposed, a fifth FBAR 565 disposed in a direction orthogonal between the second and third FBARs 562 and 562 , and first and second FBARs disposed adjacent to the third FBAR 563 . Second inductors 571 and 572 are provided. The first to fifth FBARs 561 , 562 , 563 , 564 , and 565 are electrically connected to each other, and the first and second inductors 571 and the third FBAR 563 are electrically connected to each other through a metal wire. .</p><p>11 is a conceptual diagram illustrating a configuration of a duplexer according to another embodiment of the present invention.</p><p>Referring to FIG. 11 , the duplexer 600 according to the present embodiment is formed between transmit and receive FBAR bandpass filters 605 and 610 and transmit and receive FBAR bandpass filters 605 and 610 spaced apart by a predetermined interval. Adjacent to any one of the first and second inductors 615 and 620, the capacitor 630 coupled between the first and second inductors 615 and 620, and the transmit and receive FBAR bandpass filters 605 and 610 and a deployed antenna 640 . In the manufacturing method of the duplexer shown in FIG. 11, except for the process of patterning the recess, various metal layers, piezoelectric layers, etc. into a plurality of parts, the manufacturing method of the duplexer according to the present embodiment is basically shown in FIGS. 5A to 5I. Since it is the same as the manufacturing method of the band-pass filter shown in Fig. , a description thereof will be omitted.</p>

<p>According to the present invention, since the transmission and reception bandpass filters and the inductor can be easily implemented with a single chip, it is possible to provide a duplexer having a minimum size in response to the miniaturization and weight reduction requirements of various mobile communication devices.</p><p>In addition, the transmit or receive bandpass filter according to the present invention can be implemented with a significantly smaller size than the conventional SAW bandpass filter, and has advantages such as low insertion loss and low power consumption. Accordingly, interface design and terminal operation programming can be more easily implemented, and the board area on which the duplexer is mounted can be reduced by nearly 80%.</p><p>Furthermore, since the duplexer including the transmit and receive FBAR bandpass filters according to the present invention can be easily manufactured on one substrate using the MEMS process, the manufacturing cost and time required for manufacturing the duplexer can be greatly reduced. .</p><p>Although described with reference to preferred embodiments of the present invention as described above, those skilled in the art can variously modify and modify the present invention within the scope without departing from the spirit and scope of the present invention as described in the claims below. You will understand that it can be changed.</p>