Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; 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
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
  • C23C16/45523—Pulsed gas flow or change of composition over time
  • C23C16/45525—Atomic layer deposition [ALD]
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F1/00—Etching metallic material by chemical means
• • 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 elements; Electromechanical resonators
  • H03H9/02—Details
  • H03H9/02007—Details of bulk acoustic wave devices
  • H03H9/02086—Means for compensation or elimination of undesirable effects
  • H03H9/02133—Means for compensation or elimination of undesirable effects of stress
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; 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
  • H03H9/19—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator consisting of quartz
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
  • H03H9/25—Constructional features of resonators using surface acoustic waves
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N30/00—Piezoelectric or electrostrictive devices
  • H10N30/01—Manufacture or treatment
  • H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
  • H10N30/074—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
  • H10N30/076—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing by vapour phase deposition
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N30/00—Piezoelectric or electrostrictive devices
  • H10N30/704—Piezoelectric or electrostrictive devices based on piezoelectric or electrostrictive films or coatings
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N30/00—Piezoelectric or electrostrictive devices
  • H10N30/80—Constructional details
  • H10N30/87—Electrodes or interconnections, e.g. leads or terminals

Definitions

• Frequency filters made in thin film technology such as bulk acoustic wave (BAW) filters or special surface acoustic wave (SAW) filters, find application as a frequency determining device in thin film technology.
• BAW bulk acoustic wave
• SAW surface acoustic wave
• Transmitters and receivers operating in the frequency range from several 100 MHz to about 20 GHz. Such filters are used in high-frequency technology, for example in mobile and WLAN.
• SAW filters and BAW filters are passive filters with
• BAW filters are available for transmission frequencies from about 1 GHz to 20 GHz, have a lower insertion loss (0.5 dB) than SAW filters and achieve a quality factor of over 1000.
• BAW filters can be realized in smaller sizes and are generally cheaper to produce.
• BAW resonators In the manufacture of BAW resonators in
• the piezoelectric thin film for example, an aluminum nitride, zinc oxide or PZT layer, deposited in a reactive sputter deposition on a support.
• the quality of the piezoelectric layer has a decisive influence on the technical properties of the BAW resonator.
• a crystalline and highly oriented piezoelectric layer is particularly advantageous and places high demands on the deposition process and the deposition conditions, such as pressure, temperature, homogeneity of the substrate and purity of the media.
• the piezoelectric layer in BAW fabrication is usually grown heteroepitaxially over a metal and carrier layer. This form of the
• Layer growth leads to a columnar polycrystalline piezo layer.
• a disadvantage of this type of layer growth is that it is located along topology edges on the
• Carrier layer to growth defects in the crystal structure comes. Such growth defects have consequences for the
• FIG. 1 shows a detail of a BAW resonator in cross-section during production on the basis of a scanning electron micrograph.
• TS carrier layer
• Silicon dioxide is a multilayer electrode composed of a lower first, corrosion-sensitive metal layer (M1) and an upper second metal layer (M2). The transition from the upper metal layer to the lower one
• Metal layer is of a flat topology edge, the Transition from the lower metal layer to the carrier layer is characterized by a steep topology edge.
• a piezo layer (PS) is deposited over the metal layers and the carrier layer. As the piezo layer grows, the flat topology edge is at the transition from the top
• Metal layers corrode. This happens in particular when aluminum, titanium, titanium nitride, silver or copper or multilayer systems made from these materials are used as metal layer material.
• Piezo layer form a metallic extension in the cavity can, which leads in the worst case to a short circuit in the electrode.
• Electrode must be removed so that a planar surface of electrode and dielectric emerges on the
• Piezo layer can grow up. It is also known to smooth steep topology edges by chemical etching of the metal layers. Especially for
• non-corrosion-sensitive metals usually have poor conductivity. This requires very thick electrode layers and is therefore suitable only for special types of BAW resonators.
• Metal layers or electrodes can be reduced.
• Metal layer or a structured cover of a Topologiekante is the question, it does not exclude that also a larger number of this detail can be present.
• relative terms such as on top, top, bottom, bottom, top and bottom are also used to simply describe the relationship between the various elements as illustrated in the figures. Other relative orientations, as for example by the rotation of the illustrated elements by 90 ° or 180 °
• the proposed topographical structure comprises a
• Carrier layer on which at least one structured metal layer is applied in thin-film technology is applied in thin-film technology.
• Topographic structures of this kind are, for example, in
• Thin-film technology manufactured electrodes or Multilayer electrodes Thin-film technology manufactured electrodes or Multilayer electrodes.
• the side edges of the metal layer form a topology edge in the transition to the carrier layer.
• This edge topology edge is a
• metal layer is defined here as a generic term for all metallizations that are characterized by a layer thickness above the support, which does not necessarily have to have a flat surface
• Metal layer can therefore according to the invention also consist of several, non-contiguous, one or more metals comprehensive coatings on the support layer.
• Metal layers for example a so-called
• Topology edge in the transition to an underlying arranged lower metal layer may be offset. This may be the case, for example, when an upper metal layer covers a smaller area than a lower metal layer.
• Such embodiments may, for example, by under- or overetching effects or multiple lithographic steps for
• Structuring of the metal layers may be present. It is inventively provided that along this
• topology edges with structured coverage may be present, for example when on the
• Carrier layer more than two superimposed
• two or more metal layers are arranged one above the other, of which the lower metal layer or one of the lower metal layers
• One or more of the overlying metal layers are not susceptible to corrosion or are less susceptible to corrosion than the lower metal layer (s).
• Metal layer not sensitive to corrosion or less sensitive to corrosion than the underlying metal layers.
• the function of the structured edge covering comprises corrosion protection.
• the edge cover consists of a passivating and especially against corrosive substances sufficiently dense material.
• the metal layers of the topographical structure may be, for example, aluminum, titanium, titanium nitride, silver, copper, tungsten, tantalum, molybdenum, platinum, rubidium or gold
• a corrosion-sensitive metal layer may be, for example, a layer comprising aluminum, titanium, titanium nitride, silver or copper.
• one of the metal layers may be comprehensive layers.
• a corrosion-sensitive metal layer may be, for example, a layer comprising aluminum, titanium, titanium nitride, silver or copper.
• one of the metal layers may be comprehensive layers.
• a corrosion-sensitive metal layer may be, for example, a layer comprising aluminum, titanium, titanium nitride, silver or copper.
• one of the metal layers may be comprehensive layers.
• a corrosion-sensitive metal layer may be, for example, a layer comprising aluminum, titanium, titanium nitride, silver or copper.
• the Al layer as the lower layer is also sufficiently stable against corrosion.
• the upper not or only slightly corrosion-sensitive metal layer can be a
• Tungsten tantalum, molybdenum, platinum or gold
• Tungsten and molybdenum are advantageous
• a crystal layer is deposited or grown on the topographic structure.
• the crystal layer can For example, be a non-epitaxially grown layer. It is found that on the topographic structure of the invention, the growth of the crystal layer with less pronounced growth disturbances than is the case with comparable structures.
• the crystal layer is a
• the piezoelectric layer can, for example, a
• Piezo layer Lithiumiobat or lithium tantalate include.
• the topographical structure according to the invention is part of a BAW resonator.
• the metal layer applied to the carrier layer or the metal layers applied to the carrier layer form the bottom electrode of the BAW resonator.
• the corresponding upper electrode is deposited on the piezoelectric layer.
• BAW resonators it is possible to arrange several BAW resonators one above the other with the topographic structure according to the invention. These so-called stacked BAW resonators have one
• FIGS. 2, 3 and 4 The topographical structure according to the invention is described in detail below with reference to FIGS. 2, 3 and 4. The description is for the purpose of illustration and not limitation to specific details. Also are the to
• FIG. 1 shows, in a scanning electron micrograph, a detail of a BAW resonator in cross section during the production in the intermediate step after deposition of the
• Figure 2 shows a schematic example of a
• topographical structure according to the invention in cross-section during production after the whole-area
• Figure 3 shows a schematic example of a
• FIG. 4 shows a schematic example of a topographical structure according to the invention in cross section during production after the growth of the piezoelectric layer.
• Figure 2 shows an intermediate product of the method for
• a first metal layer (Ml), wherein a Topologiekante is formed to the support layer.
• This first lower metal layer is one of two metal layers of a multilayer bottom electrode of a BAW resonator.
• Metal layer M1 is preferably made of aluminum, silver or copper or an alloy comprising aluminum, silver or copper.
• a second metal layer (M2) is applied on the first, lower metal layer.
• Metal layer M2 can terminate flush with the metal layer Ml, but also be structured so that
• Metal layer Ml is not completely covered by metal layer M2.
• the metal layer M2 is preferably one
• Tungsten tantalum, molybdenum, platinum, rubidium or gold
• a protective layer is deposited over the entire surface and edge-covering over the carrier layer and the metal layers on this structure.
• SS protective layer
• any material can be used that is not sensitive to corrosion ⁇ and the anisotropically sufficiently selective to the top metal layer of the bottom electrode is etched.
• the protective layer is a layer of
• Silicon oxide, silicon nitride or polyimide are especially used. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide. Especially, silicon oxide, silicon nitride or polyimide
• the protective layer can be deposited by means of chemical vapor deposition, plasma-enhanced chemical vapor deposition, atomic layer deposition or variants of these coating methods. Particularly advantageous is the atomic layer
• the strength of the protective layer is only through the
• the coating method produces an edge-covering protective layer which, at the marginal topology edge of the metal layers, has a greater layer thickness in the normal to the carrier layer than in the planar regions of the topographic structure.
• the topographical structure shown in FIG. 2 is subsequently subjected to an anisotropic etching process.
• the protective layer is anisotropically etched back until the planar regions of the carrier layer and the metal layer are freed from the protective layer and at the marginal topology edges of the metal layer on the basis of the here
• the structured cover (AB) is maintained.
• the anisotropic re-etching of the protective layer is achieved by physical, chemical or physico-chemical
• Dry etching for example plasma etching or
• Ion Beam Etching (Ion Milling). Particularly advantageous is the plasma etching.
• an etching process is used which has a selectivity the upper metal layer M2 and possibly also with respect to the carrier layer TS (for example Si0 2 ).
• FIG. 3 shows the topographical structure according to the invention after etching back the protective layer.
• the structured cover (AB) on the edge topology edge of the protective layer results
• topographical structure for example, the second upper metal layer M2 and the support layer TS, are
• the topology edge of the first bottom metal layer is completely covered by the structured cover AB.
• the anisotropic etching back of the protective layer described above is so long in the exemplary embodiment according to FIG.
• anisotropic etchbacks are chosen so that in comparison more or less material from the protective layer than
• structured edge covering AB is maintained and, for example, the structured edge covering extends to the planar surface of the upper metal layer.
• the piezoelectric layer is deposited by reactive sputtering, for example of pure aluminum target in a nitrogen atmosphere to form A1N.
• FIG. 4 shows the topographical structure according to the invention after the growth of the piezoelectric layer (PS).
• Edge cover leads the soft topology edge to a slight disturbance of the crystal structure, in which the

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• Acoustics & Sound (AREA)
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• Chemical Kinetics & Catalysis (AREA)
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• Plasma & Fusion (AREA)
• Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

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• 2012
  • 2012-08-03 DE DE102012107155.1A patent/DE102012107155B4/de not_active Expired - Fee Related
• 2013
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