KR20030048917A - Film bulk acoustic resonator filter duplexer - Google Patents
Film bulk acoustic resonator filter duplexer Download PDFInfo
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- KR20030048917A KR20030048917A KR1020010078970A KR20010078970A KR20030048917A KR 20030048917 A KR20030048917 A KR 20030048917A KR 1020010078970 A KR1020010078970 A KR 1020010078970A KR 20010078970 A KR20010078970 A KR 20010078970A KR 20030048917 A KR20030048917 A KR 20030048917A
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- 239000004065 semiconductor Substances 0.000 claims abstract description 15
- 239000000758 substrate Substances 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims abstract description 11
- 230000001808 coupling effect Effects 0.000 claims abstract description 7
- 230000005684 electric field Effects 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 4
- 238000010521 absorption reaction Methods 0.000 abstract 1
- 230000002238 attenuated effect Effects 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 238000010295 mobile communication Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000010897 surface acoustic wave method Methods 0.000 description 2
- 101000582320 Homo sapiens Neurogenic differentiation factor 6 Proteins 0.000 description 1
- 102100030589 Neurogenic differentiation factor 6 Human genes 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezo-electric or electrostrictive material
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/205—Constructional features of resonators consisting of piezoelectric or electrostrictive material having multiple resonators
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezo-electric or electrostrictive material
- H03H9/56—Monolithic crystal filters
- H03H9/566—Electric coupling means therefor
- H03H9/568—Electric coupling means therefor consisting of a ladder configuration
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
- H03H9/703—Networks using bulk acoustic wave devices
- H03H9/706—Duplexers
Abstract
Description
본 발명은 FBAR 필터에 관한 것으로서, 특히 복수개의 FBAR로 이루어진 FBAR 필터에서 각각의 FBAR로부터 발생되는 반사파가 감쇄되도록 하여 스퓨리어스 주파수(Spurious frequency)성분의 발생을 방지함으로써 복수개의 FBAR 필터 사이의 커플링 효과가 방지되는 FBAR 필터에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FBAR filter. In particular, in a FBAR filter composed of a plurality of FBARs, the reflection wave generated from each FBAR is attenuated, thereby preventing the occurrence of spurious frequency components. Relates to an FBAR filter to be prevented.
일반적으로 이동 통신 단말기에는 송수신 신호를 분리하여 원하는 대역의 신호를 통과시키는 역할을 수행하는 RF 부품으로 기지국이나 단말기를 통해 신호를 송수신할 때 필요한 신호만 걸러내고 불필요한 신호는 제거하는 듀플렉서가 사용된다.In general, a mobile communication terminal is an RF component that separates a transmission / reception signal and passes a signal of a desired band. A duplexer is used to filter only a signal necessary for transmitting and receiving a signal through a base station or a terminal and to remove an unnecessary signal.
이러한 듀플렉서에는 SAW(Surface acoustic wave, 이하 SAW라 함) 듀플렉서, 세라믹 듀플렉서 및 FBAR듀플렉서가 많이 사용되고 있는데, 상기 SAW 듀플렉서는 소형이면서 신호 처리가 용이하고 회로가 간략하여 무조정화 및 반도체 공정을 이용함으로써 대량 생산이 가능하나, 고주파 대역에서의 밴드폭(Band width)가 감소되어 포토리소그래피(Photolithography)가 어렵다는 문제점이 있고, 상기 세라믹(Ceramic) 듀플렉서는 안정성, 내진동 및 내충격의 이점이 있는 반면에 소자의 크기가 크다는 문제점이 있다.Many of these duplexers include surface acoustic wave (SAW) duplexers, ceramic duplexers, and FBAR duplexers. Although it can be produced, there is a problem that photolithography is difficult due to the reduction of the band width in the high frequency band, and the ceramic duplexer has the advantages of stability, vibration resistance, and impact resistance, There is a problem that the size is large.
한편, 상기 FBAR 듀플렉서는 RF 능동 소자들과 자유로운 결합이 가능하여 초경량 및 초경박이며 반도체 공정을 이용하여 대량생산이 가능하고, 특히 안정성 및 뛰어나 신호대 잡음비를 보이기 때문에 이동 통신의 통화 품질을 향상시킬 수있다.On the other hand, the FBAR duplexer can be freely combined with the RF active elements, ultra-light and ultra-thin, and can be mass-produced using a semiconductor process, and in particular, it shows stability and excellent signal-to-noise ratio, thereby improving call quality of mobile communication. have.
이와 같은 상기 FBAR 듀플렉서는 복수개의 FBAR가 직렬 및 병렬로 연결되어 이루어지는데, 상기 FBAR 는 일반적으로 도1 에 도시된 바와 같이, 전계(2)가 가해지면 진동하여 공진 특성을 유발하는 압전층(4)과, 상기 압전층(4)에 전계(2)가 공급될 수 있도록 상기 압전층(4)의 상,하부에 위치되는 상,하부 전극(6, 8)로 구성된다.The FBAR duplexer is formed by connecting a plurality of FBARs in series and in parallel. The FBAR is generally a piezoelectric layer 4 that vibrates when an electric field 2 is applied to induce resonance characteristics as shown in FIG. 1. ) And upper and lower electrodes 6 and 8 positioned above and below the piezoelectric layer 4 so that the electric field 2 can be supplied to the piezoelectric layer 4.
이때, 상기 상,하부 전극(6, 8)에 전원이 공급되면 상기 압전층(4)이 진동하여 특정 주파수에서 공진과 반공진이 일어나게 되고 공진시는 임피던스가 "0" 가 되는 제로(Zero)점과 반공진시는 임피던스가 무한대가 되는 폴(Pole)이 나타나게되어 상기 제로(Zero)점에 해당하는 주파수의 신호가 통과되고 그 이외의 신호는 차단된다.At this time, when power is supplied to the upper and lower electrodes 6 and 8, the piezoelectric layer 4 vibrates to generate resonance and anti-resonance at a specific frequency, and zero point at which impedance becomes "0". In the case of over-resonance, a pole appears to have an impedance of infinity, and a signal having a frequency corresponding to the zero point is passed, and other signals are blocked.
도2a 내지 도2c 는 일반적인 FBAR의 구조가 도시된 단면도이다.2A to 2C are sectional views showing the structure of a general FBAR.
일반적으로 FBAR 는 Bulk Micromachined 타입, Surface Micromachined 타입및 SMR(Solidly Mounted Resonator) 타입이 있는데 먼저 상기 Bulk Micromachined 타입의 FBAR 는 도2a 에 도시된 바와 같이, 반도체 기판(11)에 지지층(12)을 형성후 하부 전극(13), 압전층(14) 및 상부 전극(15)를 위치시킨 형태로써, 기계적인 진동을 향상시키기 위해 상기 반도체 기판(11)의 일부분을 에칭을 통해 제거한 구조이다.In general, FBAR has a bulk micromachined type, a surface micromachined type, and a solid-mounted resonator (SMR) type. First, the bulk micromachined type FBAR has a support layer 12 formed on a semiconductor substrate 11, as shown in FIG. The lower electrode 13, the piezoelectric layer 14, and the upper electrode 15 are positioned so that a portion of the semiconductor substrate 11 is removed by etching to improve mechanical vibration.
한편, Surface Micromachined 타입의 FBAR 는 도2b 에 도시된 바와 같이, 반도체 기판(21)과 상기 반도체 기판(21)에 형성되는 지지층(22)사이에 희생층(21a)을 형성하고, 상기 지지층(22)에 하부 전극(23), 압전층(24) 및 상부 전극(25)을 위치시킨 형태로써, 에칭공정을 사용하지 않기 때문에 공정이 간소화되는 구조이다.Meanwhile, in the surface micromachined type FBAR, as shown in FIG. 2B, the sacrificial layer 21a is formed between the semiconductor substrate 21 and the support layer 22 formed on the semiconductor substrate 21, and the support layer 22 is formed. The lower electrode 23, the piezoelectric layer 24, and the upper electrode 25 are arranged in the above-described pattern, and the process is simplified because no etching process is used.
마지막으로, SMR(Solidly Mounted Resonator) 타입의 FBAR 는 도2c 에 도시된 바와 같이, 반도체 기판(31)에 어쿠스틱 임피던스(Acoustic Impedance)의 차가 큰 두 물질(32, 33)을 격층으로 증착후 하부 전극(36), 압전층(34) 및 상부 전극(35)을 위치시킨 형태로써, 브래그반사(Bragg Reflection)을 통해 음파의 손실을 최소화한 구조이다.Lastly, as shown in FIG. 2C, a solid-mounted resonator (SMR) type FBAR is formed by depositing two materials 32 and 33 having a large difference in acoustic impedance on the semiconductor substrate 31 as a lower electrode. 36, the piezoelectric layer 34 and the upper electrode 35 are positioned to minimize the loss of sound waves through Bragg reflection.
또한, 상기 SMR(Solidly Mounted Resonator) 타입의 FBAR에 사용되는 어쿠스틱 임피던스(Acoustic Impedance)의 차가 큰 두 물질중(32, 33) 하측에 위치되는 임피던스가 큰 물질(32)로 폴리머(Polymer)를 사용하고 상기 두 물질(32, 33)중 상측에 위치되는 임피던스가 작은 물질(33)로 W, Pt 및 Au 등을 사용하게 되면 상기 두 물질(32, 33)를 통해 반사계수 1을 얻을 수 있다.In addition, polymer (Polymer) is used as a high impedance material 32 located below the two (32, 33) of the large acoustic impedance (Acoustic Impedance) used in the solid-mounted resonator (SMR) type FBAR When W, Pt, Au, etc. are used as the material having the smallest impedance 33 positioned above the two materials 32 and 33, the reflection coefficient 1 may be obtained through the two materials 32 and 33.
이때, 상기 임피던스가 큰 물질(32)의 임피던스를 Zmediunm1이라 하고 상기 임피던스가 작은 물질(33)의 임피던스를 Zmedium2이라 할 때 반사계수와 투과계수는 수학식1 과 같이 계산된다.In this case, when the impedance of the material with a large impedance 32 is Z mediunm1 and the impedance of the material with the small impedance 33 is Z medium2 , the reflection coefficient and the transmission coefficient are calculated as in Equation 1 below.
여기서, 상기 Zmediunm1과Zmedium2를 동일하게 설정할 경우 반사파없이 투과파만 나타나도록 할 수 있다.In this case, when the Z mediunm1 and the Z medium2 are set to be the same, only transmitted waves may appear without reflected waves.
도3 은 종래의 기술에 따른 래더타입의 FBAR 필터의 구조가 도시된 도면이다3 is a diagram illustrating a structure of a ladder-type FBAR filter according to the related art.
종래의 기술에 따른 래더타입 FBAR 필터는 도3 에 도시된 바와 같이, 상기 Surface Micromachined 타입, Bulk Micromachined 타입 및 SMR(Solidly Mounted Resonator) 타입의 FBAR(41, 42, 43, 44)가 직렬 및 병렬 연결되어 형성된다.In the ladder type FBAR filter according to the prior art, the surface micromachined type, bulk micromachined type, and solidly mounted resonator (SMR) type FBARs 41, 42, 43, and 44 are connected in series and in parallel as shown in FIG. It is formed.
또한, 상기 래더타입 FBAR 필터는 직렬 및 병렬 연결된 복수개의 FBAR(41, 42, 43, 44)로 신호가 입출력 될 수 있도록 하는 입출력단(45a, 45b, 45c, 45d)이 형성되고 상기 복수개의 FBAR(41, 42, 43, 44)사이에서 신호가 전달될 수 있도록 하는 배선(45)이 형성된다.In addition, the ladder-type FBAR filter is formed with input and output stages (45a, 45b, 45c, 45d) for inputting and outputting signals to a plurality of serially and in parallel connected FBAR (41, 42, 43, 44) and the plurality of FBAR A wiring 45 is formed to allow a signal to be transferred between the 41, 42, 43, and 44.
그러나, 상기와 같은 종래의 기술에 따른 FBAR듀플렉서는 통과 대역을 리플(Ripple)과 감쇄(Attenuation)를 조절하기 위하여 복수개의 FBAR 가 사용되는데 각각 인접한 FBAR 사이에 발생하는 커플링(Coupling)효과와 압전층의 측면에서 발생되는 반사파에 의해 스퓨리어스 주파수(Spurious frequency)가 발생되고 이로 인해 FBAR 듀플렉서의 특성이 저해되는 문제점이 있다.However, the FBAR duplexer according to the prior art as described above uses a plurality of FBARs to control the ripple and attenuation of the pass band, each of which has a coupling effect and a piezoelectric force between adjacent FBARs. The spurious frequency is generated by the reflected wave generated on the side of the layer, which causes a problem that the characteristics of the FBAR duplexer are impaired.
본 발명은 상기한 종래 기술의 문제점을 해결하기 위하여 안출된 것으로서, 그 목적은 FBAR 듀플렉서에 사용되는 복수개의 FBAR 사이의 커플링(Coupling)효과 및 압전층에서 발생되는 반사파를 감쇄시킴으로써, 스퓨리어스 주파수(Spurious frequency) 성분이 잡음으로 작용되어 FBAR 듀플렉서의 성능이 저해되는 것이 사전에 방지되는 FBAR 듀플렉서에 관한 것이다.SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and its object is to reduce the spurious frequency (coupling effect) between the plurality of FBARs used in the FBAR duplexer and the reflection wave generated in the piezoelectric layer, The spurious frequency component is related to the FBAR duplexer which prevents the performance of the FBAR duplexer from acting as a noise in advance.
도1 은 일반적인 FBAR 구조가 도시된 개념도,1 is a conceptual diagram illustrating a general FBAR structure;
도2a 내지 도2c 는 일반적인 FBAR의 구조가 도시된 단면도,2a to 2c are cross-sectional views showing the structure of a typical FBAR;
도3 은 종래의 기술에 따른 래더타입(Ladder-tpye)FBAR듀플렉서의 구조가 도시된 도면,3 is a diagram illustrating a structure of a ladder-tpye FBAR duplexer according to the prior art;
도4 는 본 발명에 따른 FBAR 듀플렉서의 제1 구조가 도시된 평면도,4 is a plan view showing a first structure of the FBAR duplexer according to the present invention;
도5 는 도4 의 A-A' 선 단면도,5 is a cross-sectional view taken along the line A-A 'of FIG. 4;
도6 은 본 발명에 따른 FBAR 듀플렉서의 제2 구조가 도시된 평면도,6 is a plan view showing a second structure of the FBAR duplexer according to the present invention;
도7 은 도6 의 B-B' 선 단면도이다.FIG. 7 is a cross-sectional view taken along the line B-B 'of FIG.
<도면의 주요 부분에 관한 부호의 설명><Explanation of symbols on main parts of the drawings>
50: 반도체 기판51~54: FBAR50: semiconductor substrate 51-54: FBAR
51a, 52a, 53a, 54a: 압전층51b, 52b, 53b, 54b: 상부전극51a, 52a, 53a, 54a: piezoelectric layers 51b, 52b, 53b, 54b: upper electrode
51c, 52c, 53c, 54c: 하부전극51d, 52d, 53d, 54d: 감쇄부51c, 52c, 53c, and 54c: lower electrodes 51d, 52d, 53d, and 54d: attenuation portions
상기한 과제를 해결하기 위한 본 발명에 의한 FBAR 듀플렉서의 특징에 따르면, 반도체 기판과, 상기 반도체 기판에 위치되고 전계에 의해 진동하여 공진 특성을 유발하는 압전층과, 상기 압전층의 상하부에 위치되는 전극으로 구성되는 복수개의 FBAR로 이루어진 FBAR 듀플렉서에 있어서, 상기 FBAR는 상기 FBAR의 둘레를 따라 형성되고 상기 압전층에서 발생되는 반사파를 감쇄시키고 복수개의 FBAR 사이에서 발생되는 커플링 효과를 방지하는 감쇄부를 더 포함하여 구성된다.According to a feature of the FBAR duplexer according to the present invention for solving the above problems, a semiconductor substrate, a piezoelectric layer which is located on the semiconductor substrate and vibrated by an electric field to cause resonance characteristics, and is located above and below the piezoelectric layer In the FBAR duplexer consisting of a plurality of FBAR composed of an electrode, the FBAR is formed along the periphery of the FBAR and attenuating portion to attenuate the reflection wave generated in the piezoelectric layer and to prevent the coupling effect generated between the plurality of FBAR It is configured to include more.
또한, 본 발명에 따른 FBAR 듀플렉서의 또 다른 특징에 따르면, 상기 감쇄부는 정한 폭을 가지고 상기 압전층과 대등한 높이로 상기 FBAR 의 주위를 둘러싸도록 형성된다.In addition, according to another feature of the FBAR duplexer according to the present invention, the attenuation portion has a predetermined width and is formed to surround the FBAR at a height equivalent to the piezoelectric layer.
또한, 본 발명에 따른 FBAR 듀플렉서의 또 다른 특징에 따르면, 상기 감쇄부는 상기 복수개의 FBAR 사이에 상기 압전층과 동일한 높이로 상기 물질이 충진되어형성된다.In addition, according to another feature of the FBAR duplexer according to the present invention, the attenuation portion is formed by filling the material at the same height as the piezoelectric layer between the plurality of FBAR.
이하, 본 발명의 바람직한 실시예를 첨부된 도면을 참조하여 상세히 설명한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
도4 은 본 발명에 따른 FBAR 필터의 제1 구조가 도시된 평면도이고, 도5 은 도4 의 A-A' 선 단면도이다.4 is a plan view showing a first structure of the FBAR filter according to the present invention, and FIG. 5 is a cross-sectional view taken along line AA ′ of FIG. 4.
본 발명에 의한 FBAR 듀플렉서는 반도체 기판(50)에 위치되고 전계에 의해 진동하여 공진 특성을 유발하는 압전층(51a, 52a, 53a, 54a)과 상기 압전층(51a, 52a, 53a, 54a)의 상,하부에 위치되는 상,하부전극(51b, 51c, 52b, 52c, 53b, 53c, 54b, 54c)로 구성되는 복수개의 FBAR(51, 52, 53, 54)와, 상기 복수개의 FBAR(51, 52, 53, 54)의 둘레를 따라 상기 압전층(51a, 52a, 53a, 54a)과 동일한 높이로 형성되어 상기 압전층(51a, 52a, 53a, 54a)의 측면에서 발생되는 반사파를 감쇄시키도록 하는 감쇄부(51d, 52d, 53d, 54d)로 구성된다.The FBAR duplexer according to the present invention is located on the semiconductor substrate 50, and the piezoelectric layers 51a, 52a, 53a, 54a and the piezoelectric layers 51a, 52a, 53a, 54a which are vibrated by an electric field to cause resonance characteristics. A plurality of FBARs 51, 52, 53, and 54 formed of upper and lower electrodes 51b, 51c, 52b, 52c, 53b, 53c, 54b, and 54c positioned at upper and lower portions, and the plurality of FBARs 51, respectively. Are formed at the same height as the piezoelectric layers 51a, 52a, 53a, and 54a along the circumferences of the plurality of piezoelectric layers 51a, 52a, 53a, and 54a. Attenuating portions 51d, 52d, 53d, and 54d.
이때, 상기 FBAR 듀플렉서는 SMR(Solidly Mounted Resonator) 타입의 FBAR에 적용되도록 설명하고 있으나, Bulk Micormachined 타입 또는 Membrane 타입의 FBAR에도 적용 가능하다.In this case, the FBAR duplexer has been described to be applied to an SMR (Solidly Mounted Resonator) type FBAR, but is applicable to a bulk Micormachined type or a Membrane type FBAR.
여기서, 상기 감쇄부(51d, 52d, 53d, 54d)는 상기 압전층(51a, 52a, 53a, 54a)와 동일한 높이로 소정의 폭(d)을 가지고 상기 복수개의 FBAR(51, 52, 53, 54)의 둘레를 따라 형성되다.Here, the attenuation portions 51d, 52d, 53d, and 54d may have a predetermined width d at the same height as the piezoelectric layers 51a, 52a, 53a, and 54a, and the plurality of FBARs 51, 52, 53, 54) formed along the perimeter.
또한, 상기 감쇄부(51d, 52d, 53d, 54d)는 상기 압전층(51a, 52a, 53a, 54a)에서 발생되는 수평 방향 성분의 반사파가 상기 압전층(51a, 52a, 53a, 54a)로 재반사되는 것이 방지되도록 상기 수평 방향의 반사파를 투과시키게 되는데, 상기 수평 방향의 반사파가 투과되면서 감쇄될 수 있도록 하는 것이다.In addition, the attenuation portions 51d, 52d, 53d, and 54d are configured to reflect reflected waves of horizontal components generated in the piezoelectric layers 51a, 52a, 53a, and 54a to the piezoelectric layers 51a, 52a, 53a, and 54a. The reflection wave in the horizontal direction is transmitted to prevent reflection, and the reflection wave in the horizontal direction is attenuated while being transmitted.
즉, 상기 복수개의 FBAR(51, 52, 53, 54)의 압전층(51a, 52a, 53a, 54a)로부터 발생되는 수평 방향의 반사파가 상기 감쇄부(51d, 52d, 53d, 54d)에 입력될 때의 임피던스를 Zin이라 하고, 상기 감쇄부(51d, 52d, 53d, 54d)의 임피던스를 ZX그리고 공기중의 임피던스를 Zair라 할 때 상기 수평 방향의 반사파가 상기 감쇄부(51d, 52d, 53d, 54d)로 입력될때의 임피던스 Zin은 수학식2 와 같이 계산된다.That is, the horizontal reflection waves generated from the piezoelectric layers 51a, 52a, 53a, and 54a of the plurality of FBARs 51, 52, 53, and 54 may be input to the attenuation portions 51d, 52d, 53d, and 54d. When the impedance at the time is Z in , the impedance of the attenuation portions 51d, 52d, 53d, 54d is Z X and the impedance in the air is Z air , the reflected wave in the horizontal direction is the attenuation portion 51d, 52d. , 53d and 54d), the impedance Z in is calculated as shown in Equation (2).
여기서, 상기 수학시 2에서 미설명된 d 는 상기 감쇄부(51d, 52d, 53d, 54d)의 폭을 의미하게 되고, 상기 압전층(51a, 52a, 53a, 54a)의 임피던스를 ZPZ라고 할 때를 만족하도록 상기 압전층(51a, 52a, 53a, 54a)의 임피던스를 조절하게 되면 상기 압전층(51a, 52a, 53a, 54a)에서 발생되는 수평 방향의 반사파가 상기 압전층(51a, 52a, 53a, 54a)로 재반사되지 않고 상기 감쇄부(51d, 52d, 53d, 54d)를 투과하면서 감쇄되어 상기 수평 방향의 반사파가 잡음으로 작용되는 것을 최소화할 수 있게 된다.Here, d, which is not explained in Math 2, means the width of the attenuation portions 51d, 52d, 53d, and 54d, and the impedance of the piezoelectric layers 51a, 52a, 53a, and 54a is referred to as Z PZ . time When the impedances of the piezoelectric layers 51a, 52a, 53a, and 54a are adjusted to satisfy the above, the reflected waves in the horizontal direction generated by the piezoelectric layers 51a, 52a, 53a, and 54a are transmitted to the piezoelectric layers 51a, 52a, 53a. And attenuated while passing through the attenuation portions 51d, 52d, 53d, and 54d without being reflected back to 54a, it is possible to minimize the reflected wave in the horizontal direction as noise.
상기와 같이 구성된 본 발명에 따른 FBAR 듀플렉서의 제1 구조의 동작을 살펴보면 다음과 같다.The operation of the first structure of the FBAR duplexer according to the present invention configured as described above is as follows.
먼저, 외부로부터 신호가 입력되어 상기 복수개의 FBAR(51, 52, 53, 54)를 통해 필터링되게 된다.First, a signal is input from the outside and filtered through the plurality of FBARs 51, 52, 53, and 54.
이때, 상기 복수개의 FBAR(51, 52, 53, 54)의 압전층(51a, 52a, 53a, 54a)으로부터 잡음으로 작용되는 스퓨리어스 주파수(Spurious frequency)성분의 발생 원인이 되는 수평방향의 반사파가 발생되게 된다.In this case, horizontal reflection waves are generated from the piezoelectric layers 51a, 52a, 53a, and 54a of the plurality of FBARs 51, 52, 53, and 54, causing spurious frequency components to act as noise. Will be.
상기 수평 방향의 반사파는 상기 압전층(51a, 52a, 53a, 54a)와 상기 감쇄부(51d, 52d, 53d, 54d)의 임피던스가 동일하기 때문에 상기 감쇄부(51d, 52d, 53d, 54d)로부터 상기 압전층(51a, 52a, 53a, 54a)로 재반사되지 않고 상기 감쇄부(51d, 52d, 53d, 54d)를 투과하면서 감쇄되어 상기 수평 방향의 반사파가 잡음으로 작용되는 것이 최소화 되는 것이다.The reflected waves in the horizontal direction are from the attenuation portions 51d, 52d, 53d, 54d because the piezoelectric layers 51a, 52a, 53a, 54a and the attenuation portions 51d, 52d, 53d, 54d have the same impedance. It is attenuated while passing through the attenuation portions 51d, 52d, 53d, and 54d without being reflected back into the piezoelectric layers 51a, 52a, 53a, and 54a, so that the reflected wave in the horizontal direction acts as a noise.
한편, 본 발명에 따른 FBAR 듀플렉서의 제2 구조는 도6 및 도7 에 도시된 바와 같이, 반도체 기판(60)에 형성되는압전층(61a, 62a, 63a, 64a)과 상기 압전층(61a, 62a, 63a, 64a)의 상,하부에 위치되는 상, 하부 전극(61b, 61c, 62b, 62c, 63b, 63c, 64b, 64c)로 이루어지는 복수개의 FBAR(61, 62, 63, 64)와, 상기 복수개의 FBAR(61, 62, 63, 64)사이에 상기 압전층(61a, 62a, 63a, 64a)와 동일한 높이로 감쇄부(70)가 충진되어 형성된다.Meanwhile, as shown in FIGS. 6 and 7, the second structure of the FBAR duplexer according to the present invention has piezoelectric layers 61a, 62a, 63a, and 64a formed on the semiconductor substrate 60 and the piezoelectric layers 61a, A plurality of FBARs (61, 62, 63, 64) including upper and lower electrodes (61b, 61c, 62b, 62c, 63b, 63c, 64b, 64c) positioned above and below 62a, 63a, and 64a; The attenuation part 70 is filled between the plurality of FBARs 61, 62, 63, and 64 at the same height as the piezoelectric layers 61a, 62a, 63a, and 64a.
상기와 같은 구성된 본 발명에 따른 FBAR 듀플렉서의 제2 구조 또한, 상기 수학식1 에 의해 반사계수 및 투과계수를 계산할 수 있으며, 상기 수학식2를 통해상기 압전층(61a, 62a, 63a, 64a)와 상기 감쇄부(70)와의 임피던스를 동일하게 형성할 수 있기 때문에 상기 감쇄부(70)를 통해 수평방향의 반사파가 투과되어 감쇄되게 된다.The second structure of the FBAR duplexer according to the present invention configured as described above can also calculate the reflection coefficient and the transmission coefficient by Equation 1, the piezoelectric layer (61a, 62a, 63a, 64a) through the equation (2) Since the impedance between the attenuation part 70 and the attenuation part 70 can be formed in the same manner, the reflected wave in the horizontal direction is transmitted through the attenuation part 70 to be attenuated.
이때, 상기 감쇄부(70)는 상기 복수개의 FBAR(61, 62, 63, 64)사이에 충진되어 형성되므로 상기 감쇄부(70)의 폭(d) 은 상기 복수개의 FBAR(61, 62, 63, 64)의 간격을 상기 폭(d)에 따라 배치시킴으로써, 상기 폭(d)을 조절할 수 있게 되는 것이다.In this case, since the attenuation part 70 is formed by filling between the plurality of FBARs 61, 62, 63, and 64, the width d of the attenuation part 70 is the plurality of FBARs 61, 62, and 63. , By arranging the interval of 64 along the width d, the width d can be adjusted.
결국, 본 발명에 따른 FBAR 듀플렉서의 제1 및 제2 구조는 감쇄부가 압전층으로부터 발생되는 수평방향의 반사파가 압전층으로 재반사되는 것을 방지하기 위해 투과시킬 수 있도록 감쇄부와 압전층의 임피던스를 동일하게 형성하고 감쇄부를 통해 수평방향의 반사파가 투과되면서 감쇄되어 스퓨리어스 주파수(Spurious frequency)성분이 잡음으로 작용되는 것을 최소화할 수 있게 되는 것이다.As a result, the first and second structures of the FBAR duplexer according to the present invention have the impedance of the attenuation portion and the piezoelectric layer so that the attenuation portion can be transmitted to prevent the horizontal reflection wave generated from the piezoelectric layer from being reflected back into the piezoelectric layer. It is formed in the same way and is attenuated by transmitting the reflected wave in the horizontal direction through the attenuator so that spurious frequency components can be minimized to act as noise.
상기와 같이 구성되는 본 발명의 FBAR 듀플렉서는 FBAR 듀플렉서를 구성하는 복수개의 FBAR 둘레를 둘러 싸도록 흡수 물질로 감쇄부를 형성하거나 복수개의 FBAR 사이에 흡음 물질을 충진하여 감쇄부를 형성함으로써 복수개의 FBAR 사이에서 발생되는 커플링 효과와 압전층의 측면에서 발생되는 수평 방향의 반사파를 감쇄시킴으로써 잡음이 감소되고 성능이 향상되는 효과가 있다.The FBAR duplexer of the present invention configured as described above forms an attenuation portion with an absorbent material so as to surround the plurality of FBARs constituting the FBAR duplexer or fills a sound absorbing material between the plurality of FBARs to form an attenuation portion between the plurality of FBARs. By attenuating the generated coupling effect and the horizontal reflection wave generated from the side of the piezoelectric layer, noise is reduced and performance is improved.
Claims (4)
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| US8981876B2 (en) | 2004-11-15 | 2015-03-17 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Piezoelectric resonator structures and electrical filters having frame elements |
| US9243316B2 (en) | 2010-01-22 | 2016-01-26 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Method of fabricating piezoelectric material with selected c-axis orientation |
| US9385684B2 (en) | 2012-10-23 | 2016-07-05 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator having guard ring |
| US9401692B2 (en) | 2012-10-29 | 2016-07-26 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator having collar structure |
| US9490418B2 (en) | 2011-03-29 | 2016-11-08 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator comprising collar and acoustic reflector with temperature compensating layer |
| US9490771B2 (en) | 2012-10-29 | 2016-11-08 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator comprising collar and frame |
| US9859205B2 (en) | 2011-01-31 | 2018-01-02 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Semiconductor device having an airbridge and method of fabricating the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US8981876B2 (en) | 2004-11-15 | 2015-03-17 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Piezoelectric resonator structures and electrical filters having frame elements |
| US9243316B2 (en) | 2010-01-22 | 2016-01-26 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Method of fabricating piezoelectric material with selected c-axis orientation |
| US9859205B2 (en) | 2011-01-31 | 2018-01-02 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Semiconductor device having an airbridge and method of fabricating the same |
| US9490418B2 (en) | 2011-03-29 | 2016-11-08 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator comprising collar and acoustic reflector with temperature compensating layer |
| US9385684B2 (en) | 2012-10-23 | 2016-07-05 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator having guard ring |
| US9401692B2 (en) | 2012-10-29 | 2016-07-26 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator having collar structure |
| US9490771B2 (en) | 2012-10-29 | 2016-11-08 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator comprising collar and frame |
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