KR100502569B1 - The fbar filter using selective bragg reflecting layer - Google Patents
The fbar filter using selective bragg reflecting layer Download PDFInfo
- Publication number
- KR100502569B1 KR100502569B1 KR10-2003-0023862A KR20030023862A KR100502569B1 KR 100502569 B1 KR100502569 B1 KR 100502569B1 KR 20030023862 A KR20030023862 A KR 20030023862A KR 100502569 B1 KR100502569 B1 KR 100502569B1
- Authority
- KR
- South Korea
- Prior art keywords
- layer
- film
- fbar
- reflecting layer
- bragg reflecting
- Prior art date
Links
- 238000000034 method Methods 0.000 claims abstract description 13
- 239000010409 thin film Substances 0.000 claims description 20
- 239000000758 substrate Substances 0.000 claims description 19
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 17
- 229910052710 silicon Inorganic materials 0.000 claims description 17
- 239000010703 silicon Substances 0.000 claims description 17
- 238000000151 deposition Methods 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 8
- 238000005530 etching Methods 0.000 claims description 6
- 238000001039 wet etching Methods 0.000 claims description 4
- 238000001312 dry etching Methods 0.000 claims description 3
- 230000003071 parasitic effect Effects 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 230000008569 process Effects 0.000 abstract description 3
- 239000010408 film Substances 0.000 description 46
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 11
- 229910052721 tungsten Inorganic materials 0.000 description 11
- 239000010937 tungsten Substances 0.000 description 11
- 229910004298 SiO 2 Inorganic materials 0.000 description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 9
- 229910052814 silicon oxide Inorganic materials 0.000 description 9
- 229910052782 aluminium Inorganic materials 0.000 description 6
- 239000010931 gold Substances 0.000 description 6
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 4
- 229910052750 molybdenum Inorganic materials 0.000 description 4
- 239000011733 molybdenum Substances 0.000 description 4
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 2
- QPJSUIGXIBEQAC-UHFFFAOYSA-N n-(2,4-dichloro-5-propan-2-yloxyphenyl)acetamide Chemical compound CC(C)OC1=CC(NC(C)=O)=C(Cl)C=C1Cl QPJSUIGXIBEQAC-UHFFFAOYSA-N 0.000 description 2
- 238000005240 physical vapour deposition Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 101100152879 Arabidopsis thaliana CYP708A2 gene Proteins 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- GULNIHOSWFYMRN-UHFFFAOYSA-N N'-[(4-methoxyphenyl)methyl]-N,N-dimethyl-N'-(2-pyrimidinyl)ethane-1,2-diamine Chemical compound C1=CC(OC)=CC=C1CN(CCN(C)C)C1=NC=CC=N1 GULNIHOSWFYMRN-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000005459 micromachining Methods 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- 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
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
- H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
- H03H9/175—Acoustic mirrors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/25—Constructional features of resonators using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/021—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the air-gap type
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H3/04—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks for obtaining desired frequency or temperature coefficient
- H03H2003/0414—Resonance frequency
- H03H2003/0421—Modification of the thickness of an element
- H03H2003/0442—Modification of the thickness of an element of a non-piezoelectric layer
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
본 발명은 블라그반사형의 FBAR의 제조방법에 관한 것이다.The present invention relates to a method for producing an FBAR of Blagg reflection type.
본 발명에 따르면 블라그 반사층(Bragg Reflecting Layer)(7)을 액티브에리어(Active Area) 하부에만 선택적으로 형성함으로써 소자의 체적을 감소시킬 수가 있고, 후속공정인 소잉을 용이하게 할 수 있으며, 종래에 블라그 반사층(Bragg Reflecting Layer)(7)을 따라 발생하는 탄성파의 기생성분을 감소 또는 제거하여 FBAR의 특성을 향상 시킬 수가 있다.According to the present invention, it is possible to reduce the volume of the device by selectively forming the Bragg Reflecting Layer 7 only in the lower portion of the active area, to facilitate sawing, which is a subsequent process. The characteristics of the FBAR may be improved by reducing or eliminating parasitic components of the acoustic wave generated along the Bragg Reflecting Layer 7.
Description
본 발명은, 이동통신 부품 소자에 관한 것으로, 상세하게는 특정 고주파 성분만 통과 시키는 고주파 필터를 구현하기 위한 FBAR(Film Bulk Acoustic Resonator)에 관한 것이다.The present invention relates to a mobile communication component device, and more particularly, to a FBAR (Film Bulk Acoustic Resonator) for implementing a high frequency filter that passes only a specific high frequency component.
FBAR는, 압전물질(Piezoelectric Material)을 이용하여 전자기파인 통신신호를 탄성파로 변환하여 원하는 주파수의 파장만 추출하는 역할을 하는 부품으로, 두 전극 사이에 압전박막을 증착해 전극에 전기적 에너지를 인가하면 압전층내에 시간적으로 변화하는 전계가 유기되고 이 전계는 압전결합이 잘 이루어지도록 만들어진 압전박막내에서 두께 진동방향과 동일한 방향으로 체적 탄성파(Bulk Acoustic Wave)를 유발시켜 공진을 발생시키는 원리를 이용한다. 이러한 FBAR의 제조공정은 압전물질인 ZnO, AlN을 Si나 GaAs기판 위에 압전박막층(Piezoelectric Film)을 증착하는 공정, Al, Cu, Pt, Au, Mo등으로 전극(Electrode)층을 형성하는 공정, 탄성 반사층을 형성하는 공정 등으로 나눌 수 있다. 이들 박막층은 우수한 부착력, 평탄성 및 치밀화가 이루어져야 한다.FBAR is a part that converts communication signal, which is electromagnetic wave, into elastic wave by using piezoelectric material, and extracts only the wavelength of desired frequency.FBAR deposits piezoelectric thin film between two electrodes and applies electrical energy to the electrode. The electric field that changes in time in the piezoelectric layer is induced and this electric field uses the principle of generating a resonance by inducing a bulk acoustic wave in the same direction as the thickness vibration direction in the piezoelectric thin film which is well formed. The manufacturing process of the FBAR is a process of depositing a piezoelectric film (Piezoelectric Film) of the piezoelectric material ZnO, AlN on Si or GaAs substrate, forming an electrode layer of Al, Cu, Pt, Au, Mo, etc., It may be divided into a step of forming an elastic reflective layer. These thin film layers should have good adhesion, flatness and densification.
상기 FBAR는, 에어갭(Air-gap)형태와, 블라그 반사(Bragg Reflect)형태가 있다.The FBAR has an air-gap form and a blag reflect form.
에어갭(4) 형태는 마이크로 머시닝 기법을 이용하여 실리콘(Si) 표면 기판에 희생층을 형성해 에어갭(4)을 만듬으로써, 상기 에어갭(4)을 탄성 반사층 역할을 하게 한 것이다. 이 방법은 액티브에리어(Active Area, 도 1b의 점선부분으로 외부 신호 인가시 체적 탄성파가 발생하는 부분.)(6) 하부에 에어갭(4)이 구성됨으로, 개별소자로의 절단(Sawing, 이하 소잉이라함) 시, 액티브에리어(Active Area)(6)가 파손되어 많은 불량을 일으키는 문제점을 가지고 있다.The air gap 4 forms a sacrificial layer on a silicon (Si) surface substrate using a micromachining technique to form the air gap 4, thereby making the air gap 4 serve as an elastic reflective layer. In this method, the air gap 4 is formed under the active area (the dotted line in Fig. 1B) where the volume acoustic wave is generated when an external signal is applied. In the case of sawing, the active area 6 is broken and causes a lot of defects.
블라그 반사(Bragg Reflect)형태는 실리콘 기판(5) 위에 탄성 임피던스(Acoustic Impedance) 차가 큰 물질을 격층으로 증착하여 블라그반사층 (Bragg Reflecting Layer)(7)을 구성하여 탄성 반사층 역할을 하게 한 것이다. 그러면 압전층을 통과한 탄성파에너지 (Acoustic Energy)가 기판 방향으로 전달되지 못하고 블라그 반사층에서 모두 반사되어 효율적인 공진을 발생시킬 수 있게 한 것이다, 이 방법은 외부충격에 강한 소자를 구현할 수 있는 장점을 가지고 있으므로, 소잉(Sawing) 시 액티브에리어(Active Area)(6)의 파손을 줄일 수 있다. 그러나 실리콘 기판(5)위에 블라그 반사층(7)을 형성함으로써 소자의 두께가 증가 되어, 소잉이 용이하지 않고 소잉 시 블라그반사층(7)을 구성하는 막들이 일부 벗겨지는 단점이 있다. 이는 수율 감소의 요인이 된다. 또한 소자의 체적이 증가됨으로 소자를 소형화 시키는데 한계가 있으며, 블라그 반사층을 따라서 탄성파의 기생성분(블라그 반사층을 따라서 수평방향으로 진행하는 파동)이 발생하여 필터의 특성을 감소시키는 단점이 있다.The Bragg Reflect type forms a Bragg Reflecting Layer 7 by depositing a material having a large difference in Acoustic Impedance on the silicon substrate 5 to form a Bragg Reflecting Layer 7 to serve as an elastic reflecting layer. . Then, acoustic energy passed through the piezoelectric layer is not transmitted to the substrate, but reflected from the Blag reflection layer to generate an efficient resonance. This method has the advantage of realizing an element that is resistant to external shock. As a result, breakage of the active area 6 can be reduced during sawing. However, since the thickness of the device is increased by forming the Blag reflection layer 7 on the silicon substrate 5, there is a disadvantage in that the sawing is not easy and the films constituting the Blag reflection layer 7 are partially peeled off when sawing. This is a factor in yield reduction. In addition, there is a limit to miniaturization of the device due to an increase in the volume of the device, and there is a disadvantage in that parasitic components of the acoustic wave (waves traveling in the horizontal direction along the blag reflection layer) are generated along the blag reflection layer to reduce the characteristics of the filter.
본 발명은, FBAR의 액티브에리어(Active Area)(6) 하부에만 블라그반사층 (Bragg Reflecting Layer)(8)을 선택적으로 형성함으로써 상기 블라그반사층 (Bragg Reflecting Layer)(8)을 따라 발생하는 탄성파(Acoustic wave)의 기생성분을 감소시켜 FBAR의 특성을 향상시키고, 후속 공정으로 소잉을 용이하게 하는데 있다.According to the present invention, an acoustic wave generated along the Bragg reflecting layer 8 by selectively forming a Bragg reflecting layer 8 only under an active area 6 of the FBAR. By reducing the parasitic constituents of the acoustic wave, the characteristics of the FBAR are improved, and subsequent processing is easy to saw.
상기 목적을 달성하기 위한 본 발명에 따른 FBAR의 제조방법은 다음 순서와 같다.Method for producing FBAR according to the present invention for achieving the above object is as follows.
첫째는, 실리콘 기판상(5)에 FBAR의 액티브에리어(Active Area) 가 위치할 곳을 식각하는 제 1단계이다,The first step is to etch where the active area of the FBAR will be located on the silicon substrate 5,
둘째는, 상기 식각된 곳에 블라그반사층(Bragg Reflecting Layer)(8)을 형성하는 제 2단계이다.The second step is to form a Bragg Reflecting Layer 8 in the etched place.
셋째는, 상기 블라그반사층(Bragg Reflecting Layer)(8) 상부에 바텀전극(Bottom Electrode)(1)층을 증착하는 제 3단계이다.Third, a third step of depositing a bottom electrode (1) layer on the Bragg Reflecting Layer (8).
네째는, 상기 바텀전극(Bottom Electrode)(1)층 표면에 적정 두께로 압전물질을 증착하여, 압전박막(2)층을 형성하는 제 4단계이다.The fourth step is to form a piezoelectric thin film layer 2 by depositing a piezoelectric material with an appropriate thickness on the bottom electrode 1 surface.
다섯째는, 상기 압전박막(2)층 위에 탑전극(Top Electrode)(3)층을 형성하는 제 5단계이다.Fifth, a fifth step of forming a top electrode (3) layer on the piezoelectric thin film (2) layer.
상기한 바와 같이 다섯 단계를 구비하여 본 발명을 구현할 수 있다.As described above, the present invention can be implemented by providing five steps.
상기 블라그반사층은 실리콘산화(SiO 2)막과 텅스텐(W)막을 번갈아 홀수 층으로 형성할 수 있다. 물론 실리콘산화(SiO 2)막이나 텅스텐(W)막이 아니더라도 탄성임피던스( Acoustic Impedence)차이가 있는 서로 다른 두 가지 물질을 번갈아 적층할 수도 있다.The Blag reflection layer may be formed as an odd layer alternately between a silicon oxide (SiO 2 ) film and a tungsten (W) film. Of course, even if not a silicon oxide (SiO 2 ) film or tungsten (W) film, two different materials with an acoustic impedance difference may be alternately stacked.
상기 바텀전극(Bottom Electrode)층을 이루는 박막은 금(Au)막, 알루미늄(Al)막, 텅스텐(W)막, 은(Ag)막, 몰리브덴(Mo)막 및 인듐(In)막 중에서 어느 하나일 수 있으며, 상기 탑전극층을 이루는 박막은 금(Au)막, 알루미늄(Al)막, 몰리브덴(Mo)막 및 텅스텐(W) 막중에서 어느 하나일 수 있으며, 상기 압전물질은 산화아연(ZnO) 또는 알루미늄나이트라이드(AlN)인 것이 바람직하다.The bottom electrode thin film forming the bottom electrode layer is any one of a gold (Au) film, an aluminum (Al) film, a tungsten (W) film, a silver (Ag) film, a molybdenum (Mo) film and an indium (In) film. The thin film constituting the top electrode layer may be any one of a gold (Au) film, an aluminum (Al) film, a molybdenum (Mo) film, and a tungsten (W) film, and the piezoelectric material may be zinc oxide (ZnO). Or aluminum nitride (AlN).
상기 바텀전극층과 압전박막층 사이, 또는 상기 압전박막층과 탑전극층 사이에 외부온도 변화로부터 소자의 공진 주파수 변동을 방지하기 위한 보호막으로 실리콘산화막(SiO 2)을 더 형성하는 것이 바람직하다.It is preferable to further form a silicon oxide film (SiO 2 ) as a protective film between the bottom electrode layer and the piezoelectric thin film layer or between the piezoelectric thin film layer and the top electrode layer as a protective film for preventing the resonance frequency variation of the device from a change in external temperature.
이하, 본 발명의 구체적인 일 실시예를, 첨부한 도면을 참조하여 상세히 설명한다.Hereinafter, a specific embodiment of the present invention will be described in detail with reference to the accompanying drawings.
제 1단계; 실리콘 기판상에 FBAR의 액티브에리어(Active Area)가 위치할 곳을 식각 한다. 도 3에 도시한 바와 같이, 실리콘 기판상에 식각액(Etchant) TMAH((CH3)4 NOH)를 사용하여 이방성(Anisotropic)으로 식각(Etching)한다. 이방성 식각(Anisotropic Etching)된 표면을 주사현미경으로 관찰하면 표면이 평탄하지 않고 미세돌출부(9)들이 생성되어 있는 것을 알 수 있다. 이것을 도 3의 상세도에 나타내고 있다. 상기 이방성 식각된 실리콘 기판에 열산화막(SiO2)을 증착한 후 불산(HF)으로 제거하면, 이방성 식각(Anisotropic Etching)된 표면의 평탄도를 개선할 수 있다. 상기 표면의 평탄도는 개선할 필요가 있는데, 상기 표면의 평탄도가 개선되지 않으면 후속공정인 블라그 반사층의 경계면의 평탄도가 불량하게 되고 이것은 탄성파(Acoustic wave)를 산란 시키는 역할을 하게 되어 FBAR의 특성을 감소 시킨다.First step; The active area of the FBAR is etched on the silicon substrate. As shown in FIG. 3, an etchant is etched using an etchant TMAH ((CH 3 ) 4 NOH) on a silicon substrate. Observing the anisotropically etched surface with a scanning microscope, it can be seen that the surface is not flat and the microprojections 9 are formed. This is shown in the detail of FIG. If the thermal oxide film (SiO 2 ) is deposited on the anisotropically etched silicon substrate and then removed by hydrofluoric acid (HF), the flatness of the anisotropic etched surface may be improved. The flatness of the surface needs to be improved. If the flatness of the surface is not improved, the flatness of the interface of the Blag reflection layer, which is a subsequent process, becomes poor, which serves to scatter acoustic waves, which causes FBAR. Reduces the properties of
상기 식각에는 습식식각(Wet etching) 또는 건식식각(Dry etching)이 있다. 습식식각(Wet etching)은 HNA(HNO3+HF+CH3COOH), KOH, TMAH((CH3)4 NOH)등을 식각액(Etchant)으로 사용하며, 건식식각(Dry etching)은 XeF2, 플라즈마소스(Plasma source)인 SF6, CF4, CCl4 등을 사용하여 식각 한다.The etching may be wet etching or dry etching. Wet etching uses HNA (HNO 3 + HF + CH 3 COOH), KOH, TMAH ((CH 3 ) 4 NOH) as an etchant, and dry etching is XeF 2 , Etch using a plasma source SF 6 , CF 4 , CCl 4, etc.
본 발명에서는, THAH((CH3)4NOH)을 식각액(Etchant)으로 사용하는 습식식각의 예를 들었지만, 건식식각일지라도, 또한 이방성 혹은 등방성식각 일지라도 실리콘 기판의 액티브에리어(Active area)가 위치할 곳을 식각하는 것은 본 발명의 기술사상임은 물론이다.In the present invention, the wet etching method using THAH ((CH 3 ) 4 NOH) as an etchant is given. Of course, etching the place is a technical idea of the present invention.
제 2단계; 상기 식각된 실리콘 기판상에 아래의 방법으로 블라그반사층(Bragg Reflecting Layer)(8)을 형성한다.Second step; A Bragg Reflecting Layer 8 is formed on the etched silicon substrate by the following method.
제1탄성 임피던스를 갖는 실리콘산화(SiO 2)막과, 상기 제 1 탄성 임피던스보다 큰, 제2탄성 임피던스를 갖는 텅스텐(W)막을 번갈아 증착한다. 즉, 상기 실리콘산화(SiO2)막과 상기 텅스텐(W)막이 순차적으로 한 쌍(Pair)을 이루도록 증착하며, 최상층은 상기 실리콘산화(SiO 2)막을 증착하여 전체적으로 홀수층을 갖는 블라그반사층(Bragg Reflecting Layer)를 형성한다. 탄성 임피던스는 상기 실리콘산화(SiO 2)막 보다 상기 텅스텐(W)막이 더 크다. 상기 실리콘산화(SiO 2)막과 텅스텐(W)막의 증착은 물리기상증착(Physical Vapour Deposition)방법을 사용하면 된다. 물론 화학기상증착방법(Chemical Vapour Deposition)으로 형성할 수도 있다. 상기 블라그반사층(Bragg Reflecting Layer) 은 탄성파소자 특성에 따라 반복해서 증착하여 홀수 층으로 다양하게 형성할 수 있다. 본 실시예에서는 7층 구조의 블라그반사층(Bragg Reflecting Layer)을 형성한다. 상기 실리콘산화(SiO 2)막의 두께와 상기 텅스텐(W)막의 두께는 탄성파의 파장을 λ라고 할 때,λ/4 의 관계를 만족하도록 한다.A silicon oxide (SiO 2 ) film having a first elastic impedance and a tungsten (W) film having a second elastic impedance greater than the first elastic impedance are alternately deposited. That is, the silicon oxide (SiO 2 ) film and the tungsten (W) film are deposited to form a pair sequentially, and the uppermost layer is a Blag reflection layer having an odd layer as a whole by depositing the silicon oxide (SiO 2 ) film ( Bragg Reflecting Layer). The elastic impedance of the tungsten (W) film is larger than that of the silicon oxide (SiO 2 ) film. The deposition of the silicon oxide (SiO 2 ) film and the tungsten (W) film may be performed using a physical vapor deposition method. Of course, it can also be formed by chemical vapor deposition (Chemical Vapor Deposition). The Bragg Reflecting Layer may be variously formed as an odd layer by repeatedly depositing it according to the characteristics of the acoustic wave device. In the present embodiment, a 7-layer Bragg Reflecting Layer is formed. The thickness of the silicon oxide (SiO 2 ) film and the thickness of the tungsten (W) film satisfy the relationship of λ / 4 when the wavelength of the acoustic wave is λ.
제 3단계; 상기 블라그반사층(Bragg Reflecting Layer)(8) 상부에 바텀전극(Bottom Electrode)(1)층을 증착 한다. 바텀전극(1)층으로는 알루미늄(Al)막 이외에 텅스텐막(W), 은막(Ag), 몰리브덴(Mo)막 및 인듐막(In) 중에서 어느 하나를 사용할 수 있다.Third step; A bottom electrode (1) layer is deposited on the Bragg Reflecting Layer 8. In addition to the aluminum (Al) film, any one of tungsten film W, silver film (Ag), molybdenum (Mo) film, and indium film (In) may be used as the bottom electrode (1) layer.
제 4단계; 상기 바텀전극(1)층 상에 압전박막(2)층인 산화아연(ZnO)막(2) 또는 알루미늄나이트라이드(AlN)막(2)을 형성한다. 이때, 상기 압전박막(2)층의 증착은 물리기상증착(Physical Vapour Deposition)방법을 사용하면 된다.The fourth step; A zinc oxide (ZnO) film 2 or an aluminum nitride (AlN) film 2, which is a piezoelectric thin film 2 layer, is formed on the bottom electrode 1 layer. In this case, the deposition of the piezoelectric thin film layer 2 may be performed using a physical vapor deposition method.
상기 압전박막(2)층의 두께 d는, 관계식 d=v/2f 0에 따라서 구하면 된다. 여기서 v는 상기 압전박막(2)층의 구성물질 내에서 탄성파속도, f 0는 중심 대역 주파수이다. 따라서, 탄성파소자의 중심 대역 주파수(f 0)를 2GHz라고 할 때 상기 압전박막(2)층이 산화아연(ZnO)막(2)인 경우 그 두께는 약 15825Å임을 알 수 있다.The thickness d of the piezoelectric thin film (2) layer is therefore ask a relational expression d = v / 2f 0. Where v is the elastic wave velocity in the constituent material of the piezoelectric thin film 2 layer, and f 0 is the center band frequency. Therefore, when the center band frequency f 0 of the acoustic wave element is 2 GHz, it can be seen that the thickness of the piezoelectric thin film layer 2 is a zinc oxide (ZnO) film 2 is about 15825 kHz.
제 5단계; 상기 압전박막(2)층위에 탈전극(Top Electrode)(3)층을 형성한다. 탑전극(Top Electrode)(3)층으로는 알루미늄(Al)막을 1000내지 1300 Å증착한다. 상기 탑전극(3)층의 박막은 상기 알루미늄(Al)막 이외에 금(Au)막 또는 텅스텐(W)막 또는 몰리브덴(Ho)막일 수 있다.The fifth step; A top electrode (3) layer is formed on the piezoelectric thin film (2) layer. As the Top Electrode 3 layer, an aluminum (Al) film is deposited at 1000 to 1300 Å. The thin film of the top electrode 3 layer may be a gold (Au) film, a tungsten (W) film, or a molybdenum (Ho) film in addition to the aluminum (Al) film.
본 발명의 FBAR의 제조방법은 이상과 같이 다섯 가지 단계로 이루어진다.The manufacturing method of the FBAR of the present invention consists of five steps as described above.
상기 방법으로 제조된 FBAR의 단면도를 도 5에 나타내었다.A cross-sectional view of the FBAR prepared by the above method is shown in FIG. 5.
도 6a는 종래의 블라그반사형의 FBAR를 필터회로화 하였을 때, 탄성파의 기생성분(도 6a에서 화살표)이 인접소자(FBAR)와 상호작용 하는 것을 나타낸 도면으로, 상기 상호작용으로 인해 리플이 발생하는 등 필터의 특성에 좋지 않은 영향을 준다. 따라서 도 6b와 같이 FBAR의 액티브에리어 하부에만 선택적으로 블라그 반사층을 구성함으로써, 인접소자(FBAR)의 블라그 반사층 사이에, 상기 블라그 반사층과 다른 매질인 실리콘 기판이 존재함으로 탄성파의 기생성분을 감소 또는 제거할 수가 있다.FIG. 6A illustrates a parasitic component of an acoustic wave (arrow in FIG. 6A) interacting with an adjacent element (FBAR) when the FBAR of the conventional BAG reflection type is formed in a filter circuit. This can adversely affect the characteristics of the filter. Therefore, as shown in FIG. 6B, the Blag reflection layer is selectively formed only under the active area of the FBAR, so that the parasitic component of the acoustic wave is formed between the Blag reflection layer of the adjacent element FBAR by the presence of a silicon substrate which is a different medium from the Blag reflection layer. Can be reduced or eliminated.
소잉 시, 종래의 블라그 반사형인 도 6a는, 블라그 반사층과 실리콘 기판이 소잉 대상이 되지만 본 발명인 도 6b는 실리콘 기판만이 소잉 대상임으로, 본 발명에 따르면, 소잉 시 박막층이 벗겨지는 현상은 일어날 수가 없다. 또한 실리콘 기판을 식각한 곳에 블라그반사층이 형성되어, 본 발명인 도 6b는, 종래의 블라그 반사형인 도 6a 보다 소자의 두께가 1/2 이상 감소되어 있음을 알 수 있다.In the sawing, FIG. 6A, which is a conventional Blag reflection type, is a sawing object and a silicon substrate, but only the silicon substrate of FIG. 6B of the present invention is a sawing object. Can't happen. In addition, since the Blag reflection layer is formed at the place where the silicon substrate is etched, it can be seen that FIG. 6B of the present invention reduces the thickness of the device by at least 1/2 than that of FIG.
상술한 바와 같이 본 발명에 의하면, 종래의 블라그반사 형태의 FBAR가 가지고 있는 단점들을 제거할 수가 있다. 즉, 소잉 시 블라그 반사층(Bragg Reflecting Layer)(7)을 구성하는 박막들이 벗겨지는 문제를 제거하여 수율향상에 기여할 수가 있고, 종래의 FBAR보다 체적을 감소시킴으로 초소형화에 기여할 수가 있으며, 종래에 블라그 반사층(Bragg Reflecting Layer)(7)을 따라서 발생하는 탄성파(Acoustic wave)의 기생성분을 감소시켜서 FBAR의 특성을 향상시킬 수가 있다.As described above, according to the present invention, it is possible to eliminate the disadvantages of the FBAR of the conventional Blag reflection type. In other words, the thin film constituting the Bragg Reflecting Layer 7 can be removed to reduce the problem of peeling, which contributes to the improvement of yield, and can contribute to the miniaturization by reducing the volume of the conventional FBAR. The parasitic component of the acoustic wave generated along the Bragg Reflecting Layer 7 can be reduced to improve the characteristics of the FBAR.
도 1a은 에어갭 형태의 FBAR의 단면도.1A is a cross-sectional view of an FBAR in the form of an air gap.
도 1b은 에어갭 형태의 FBAR의 평면도.1B is a plan view of an FBAR in the form of an air gap.
도 2는 블라그반사 형태의 FBAR의 단면도.2 is a cross-sectional view of the FBAR in the form of a blag reflection.
도 3은 실리콘 기판을 이방성 에칭한 단면도3 is a cross-sectional view of anisotropically etching a silicon substrate
도 4는 본 발명에 따른, 블라그 반사층을 형성한 단면도.4 is a cross-sectional view of a blag reflective layer formed in accordance with the present invention.
도 5는 본 발명에 따른, 선택형 블라그 반사층을 이용한 FBAR의 단면도.5 is a cross-sectional view of an FBAR using an optional blag reflective layer, in accordance with the present invention.
도 6a는 종래의 블라그반사형의 FBAR 필터의 단면도.6A is a cross-sectional view of a conventional Blag reflection type FBAR filter.
도 6b는 본 발명에 따른, 블라그반사형의 FBAR 필터의 단면도.6B is a cross-sectional view of a Blag reflection type FBAR filter, in accordance with the present invention.
도면의 주요 부분에 대한 부호의 설명Explanation of symbols for the main parts of the drawings
1 ; 바텀전극One ; Bottom electrode
2 ; 압전박막2 ; Piezoelectric Thin Film
3 ; 탑전극3; Top electrode
4 ; 에어갭4 ; Air gap
5 ; 실리콘 기판5; Silicon substrate
6 ; 액티브에리어6; Active Area
7 ; 블라그 반사층7; Blag Reflective Layer
8 ; 본 발명에 따른 블라그 반사층8 ; Blag reflective layer according to the present invention
9 ; 돌출부9; projection part
10 ; 경계면10; Boundary
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2003-0023862A KR100502569B1 (en) | 2003-04-15 | 2003-04-15 | The fbar filter using selective bragg reflecting layer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2003-0023862A KR100502569B1 (en) | 2003-04-15 | 2003-04-15 | The fbar filter using selective bragg reflecting layer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR20030036534A KR20030036534A (en) | 2003-05-09 |
| KR100502569B1 true KR100502569B1 (en) | 2005-07-20 |
Family
ID=29579347
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR10-2003-0023862A KR100502569B1 (en) | 2003-04-15 | 2003-04-15 | The fbar filter using selective bragg reflecting layer |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR100502569B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013181562A1 (en) * | 2012-05-31 | 2013-12-05 | Texas Instruments Incorporated | Temperature-controlled integrated piezoelectric resonator |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012137574A1 (en) * | 2011-04-01 | 2012-10-11 | ルネサスエレクトロニクス株式会社 | Semiconductor device, method for manufacturing same, and portable telephone |
| CN108449066B (en) * | 2018-05-14 | 2024-02-27 | 杭州左蓝微电子技术有限公司 | Surface acoustic wave resonator based on solid reflecting layer and manufacturing method thereof |
-
2003
- 2003-04-15 KR KR10-2003-0023862A patent/KR100502569B1/en not_active IP Right Cessation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013181562A1 (en) * | 2012-05-31 | 2013-12-05 | Texas Instruments Incorporated | Temperature-controlled integrated piezoelectric resonator |
| US9240767B2 (en) | 2012-05-31 | 2016-01-19 | Texas Instruments Incorporated | Temperature-controlled integrated piezoelectric resonator apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20030036534A (en) | 2003-05-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7161448B2 (en) | Acoustic resonator performance enhancements using recessed region | |
| CN110324022B (en) | Resonator and preparation method thereof | |
| US6924717B2 (en) | Tapered electrode in an acoustic resonator | |
| US7212082B2 (en) | Method of manufacturing piezoelectric thin film device and piezoelectric thin film device | |
| JP4428354B2 (en) | Piezoelectric thin film resonator | |
| KR100662865B1 (en) | Film bulk acoustic resonator and the method for manufacturing the same | |
| JP7081041B2 (en) | Thin-film bulk acoustic wave resonators and their manufacturing methods, filters, and radio frequency communication systems | |
| EP1480335A2 (en) | Method of manufacturing film bulk acoustic resonator using internal stress of metallic film and resonator manufactured thereby | |
| WO2007119556A1 (en) | Piezoelectric resonator and piezoelectric filter | |
| JP2004064786A (en) | Resonator having seed layer | |
| GB2424775A (en) | Thin film acoustic resonator suppresses parasitic modes to improve Q | |
| JP4395892B2 (en) | Piezoelectric thin film device and manufacturing method thereof | |
| JP2008022305A (en) | Thin-film piezoelectric resonator and its manufacturing method | |
| JP4775445B2 (en) | Thin film piezoelectric resonator and thin film piezoelectric filter | |
| JP2006060385A (en) | Resonator and filter using the same | |
| JP2008182543A (en) | Thin film piezoelectric resonator and thin film piezoelectric filter using the same | |
| JP2006197147A (en) | Piezoelectric thin-film resonator and filter using the same | |
| JP2002076824A (en) | Piezoelectric thin film resonator, filter and electronic device | |
| KR100502569B1 (en) | The fbar filter using selective bragg reflecting layer | |
| JP5128077B2 (en) | Thin film piezoelectric resonator and thin film piezoelectric filter using the same | |
| JP5202252B2 (en) | Acoustic wave resonator | |
| KR20030036533A (en) | The bragg reflecting type fbar using surface mems | |
| JP2005348357A (en) | Thin film bulk sound resonator | |
| KR20050034226A (en) | The fbar using a wave length of acoustic wave. | |
| CN118631211A (en) | Resonator and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A201 | Request for examination | ||
| E902 | Notification of reason for refusal | ||
| E701 | Decision to grant or registration of patent right | ||
| N231 | Notification of change of applicant | ||
| GRNT | Written decision to grant | ||
| LAPS | Lapse due to unpaid annual fee | ||
| FPAY | Annual fee payment |
Payment date: 20090406 Year of fee payment: 4 |
|
| R401 | Registration of restoration |