Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R19/00—Electrostatic transducers
  • H04R19/005—Electrostatic transducers using semiconductor materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
  • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
  • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
  • B81C1/00023—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems without movable or flexible elements
  • B81C1/00047—Cavities
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
  • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
  • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
  • B81C1/00023—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems without movable or flexible elements
  • B81C1/00103—Structures having a predefined profile, e.g. sloped or rounded grooves
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
  • B81B2201/00—Specific applications of microelectromechanical systems
  • B81B2201/02—Sensors
  • B81B2201/0257—Microphones or microspeakers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
  • B81B2203/00—Basic microelectromechanical structures
  • B81B2203/03—Static structures
  • B81B2203/0315—Cavities
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
  • B81B2203/00—Basic microelectromechanical structures
  • B81B2203/03—Static structures
  • B81B2203/0369—Static structures characterized by their profile
  • B81B2203/0392—Static structures characterized by their profile profiles not provided for in B81B2203/0376 - B81B2203/0384

Definitions

• the invention relates to a micromechanical component and a method for its production according to the preambles of the independent claims.
• Micromechanical sensors often use membranes that are located above a cavity. In certain sensors, such as MEMS microphones, the size and shape of this cavity affects the resolution of the
• a MEMS microphone but also a membrane sensor is realized by means of a two-stage process.
• a sensor element 120 which has, for example, a membrane and a counter electrode 130, a on
• a cavern 110 is subsequently introduced into the substrate from the rear side 170 of the semiconductor substrate 100, which reaches as far as the active sensor structure, ie, for a microphone, for example, up to counter-electrode 130.
• the formation of the cavern 110 can be achieved by means of a single Trenchiervonreaes. However, it is necessary here that the etching front must strike the active sensor structure very precisely, since otherwise a mechanical / acoustic short circuit could occur if the cavern opening is displaced from the sensor structure. If, on the other hand, the opening of the cavern is designed too small with respect to the size of the sensor structure, the sensor structure, for example a membrane, is unnecessarily damped.
• a minimum volume must be maintained at the opening below the sensor structure, especially when using an M E M S microphone, to allow sufficient sensitivity. To increase the sensitivity, however, it is desirable to make this volume as large as possible. In contrast, the volume can not be increased arbitrarily, since the surface on the back side 170 of the component is used in further processing to mount the component on printed circuit boards or in housings. Therefore, a middle ground must be found between a large back volume and a sufficiently large mounting surface on the back of the substrate.
• FIG. 1b Another known example of increasing the back volume is shown in FIG. 1b.
• a two-stage Trenchierlui was used in comparison to the device of Figure Ia.
• a cavern 140 with a larger opening than the active sensor structure 130 is introduced into the substrate 100 with a first trench etching step.
• a smaller cavern 150 is generated, which is adapted to the dimensions of the sensor element 120 or the sensor structure 130.
• a larger back volume, consisting of the caverns 140 and 150 and thus an increase in sensitivity can be achieved with this method, the expense associated with the two separate structuring steps is significantly increased compared to the component of FIG.
• any enlargement of the cavity 140 is not possible because on the back side 170 of the substrate 100, a sufficient surface must be provided for attachment.
• the present invention describes a micromechanical component or a method for producing such a component, in which, starting from an opening in the rear side of a monocrystalline semiconductor substrate, a cavity is produced in the substrate.
• the process used for this purpose is controlled in conjunction with the monocrystalline semiconductor substrate used such that a largely rectangular cavity is formed.
• a sensor element is applied to the front side of the semiconductor substrate.
• an opening in the front side of the semiconductor substrate is provided starting from the cavity.
• a microphone is provided as the sensor element, in which a media exchange between the cavity and the region between the membrane and the counter electrode is necessary as pressure equalization.
• the counterelectrode is structured directly in the front side of the semiconductor substrate and the membrane is applied as an additional component to the semiconductor substrate.
• the walls are aligned in the use of a monocrystalline semiconductor substrate in the corresponding crystal directions.
• a monocrystalline semiconductor substrate for example, in the case of a (100) crystal, formation of walls in the ⁇ 110> direction can be observed, while the transitions between the walls run in the ⁇ 100> direction. These transitions are diminished by the
• the inventive design of the rectangular cavity below the membrane or counter electrode can be realized in the semiconductor substrate, a larger volume compared to an oval configuration. This allows a larger media intake. In addition, an increase in the sensitivity of the sensor element can be achieved thereby. Furthermore, it is thus possible to produce thinner and smaller sensor elements, in particular microphones.
• FIGS. 2a to 2d show the production of the rectangular cavity.
• FIG. 3 shows a cross section through the cavity according to the invention.
• FIG. 4 shows a particular exemplary embodiment in FIG
• a sensor element 220 is applied to a monocrystalline semiconductor substrate 200.
• a monocrystalline semiconductor substrate 200 This may be both a conventional micromechanical membrane sensor but also a micromechanically manufactured microphone.
• the membrane or the counter element or the counter electrode 230 can be applied directly to the substrate.
• the sensor element 220 it is also possible for the sensor element 220 to be applied to the front side 310 of the substrate 200 in such a way that there is a greater or lesser distance between the membrane and the counter element, in order to prevent direct contact and thus damage during production avoid.
• a mask 240 is applied to the rear side of the substrate 200, which forms the later cavity
• the trench etching process As shown in FIG. 2 a, an approximately perpendicular depression is introduced into the substrate 200, which forms the cavity 210.
• a passivation 250 builds up on the side wall of the cavern.
• the trench etching process should be approximately half the thickness of the
• Substrate 200 are performed.
• an isotropic etching step for example by means of an SF 6 etch, can be introduced into the depth of the substrate. This optional step shortens the
• the size of the cavity 270 i. the lateral extent of the cavity 270 in the substrate 200 can be determined over the etching time. It is thus possible to produce a cavity which extends laterally with respect to the sensor element 220 or the membrane or the counter-electrode 230 and which has the same depth on all sides.
• the cavity 270 is opened to the sensor element 220 or to the membrane or the counterelectrode 230 by means of an (ansisotropic) trench etching process through the opening 215 produced in the first trench etching process.
• an (ansisotropic) trench etching process through the opening 215 produced in the first trench etching process.
• the etching mask 240 and the passivation layer 250 can also be removed in a further step before the component is separated.
• the effect of the different propagation of the etching fronts on the basis of the crystal orientations in a monocrystalline semiconductor substrate can be illustrated.
• the etch rate in the ⁇ 100> direction 340 is smaller than in the ⁇ 110> direction 350, and therefore, the walls 320 of the cavity 270 are nearly square.
• the anisotropic etching process also acts on the mask opening 215 in that there likewise arises a rectangular or square etching front 330.
• Opening 280 a plurality of smaller openings 400 to produce as a through hole to the sensor element 420, as shown in Figure 4. It can also be provided that the counterelectrode 410 is introduced directly into the front side of the substrate 200. If appropriate, an additional doping of this area can also be undertaken.
• the advantage of this embodiment is that not the entire ME MS microphone has to be applied to the substrate 200, but only the sensor element 420 provided with the membrane 430. R324370

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Pressure Sensors (AREA)
• Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=40940224

Family Applications (1)

Country Status (5)

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Family Cites Families (34)

• 2008
  • 2008-07-22 DE DE102008040597A patent/DE102008040597A1/de not_active Ceased
• 2009
  • 2009-06-03 CN CN200980128720.3A patent/CN102106161B/zh active Active
  • 2009-06-03 US US12/737,521 patent/US8692339B2/en active Active
  • 2009-06-03 EP EP09779612A patent/EP2308243A1/de not_active Withdrawn
  • 2009-06-03 WO PCT/EP2009/056774 patent/WO2010009934A1/de active Application Filing

Non-Patent Citations (1)

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