JP2006231439A - Fine mechanical element and its manufacturing method, semiconductor device and communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fine driving element capable of sufficiently reducing or avoiding deterioration of a driving part caused by charged effects by polar molecules and oxidation of an energizing part by remaining oxidizing molecules and conductive molecules. <P>SOLUTION: A fine driving part is provided in a space filled with a reducing atmosphere having inert gas and reducing gas as main components. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a micromechanical element, in particular, an electrically driven micromechanical element and a manufacturing method thereof, a semiconductor device having the micromechanical element, and a communication apparatus using the micromechanical element as a bandpass filter.

An element having a micromechanical structure, that is, a so-called MEMS (Micro Electro Mechanical System) device is subjected to an airtight sealing process, so-called hermetic packaging, in order to ensure initial characteristics and maintain characteristics, that is, to guarantee reliability in products. .
This micro mechanical element is also used as an electronic element such as a filter, a mixer, a resonator, a signal switch, and a sensor. However, the configuration in which the micro drive unit constituting the element is packaged in a reduced-pressure atmosphere is a characteristic of the element due to the charging effect. It is known that it is effective in reducing deterioration. For example, it has been reported that it is particularly effective to configure the resonator with a high vacuum package of about 50 μTorr in order to maintain a high Q value of the vibrator. (For example, refer nonpatent literature 1).

However, since the above-described electronic elements are required to have a high degree of precision in operation and control, it is difficult to sufficiently reduce or avoid the characteristic deterioration only by packaging the micro drive unit in a reduced pressure atmosphere.
That is, when polar molecules such as water remain in the package even under a reduced pressure atmosphere, the molecules generated by the electric field near the micro-driving unit constituting the element are accompanied by the operation of the element such as voltage application. Although charging effects such as arrangement and electrolysis occur, for example, if charges are concentrated (charging) on a part of the surface of the vibrator, for example, the neutral position of the vibrator is biased, and the element function is impaired. .

In addition, the charging effect caused by such polar molecules also causes the alteration of the minute driving portion and the surrounding wiring material. In general, an electric signal having a higher frequency has a property of propagating through the surface portion of the wiring. Therefore, if the surface portion is altered by oxidation or the like, the resistance increases and the device characteristics deteriorate due to a decrease in propagation characteristics.
Therefore, even under a reduced pressure atmosphere, as long as polar molecules remain, the selection of the wiring material that constitutes the micromechanical element has priority over the point that it is less likely to be altered than the resistance inherent in the material itself. There was a fact that it had to be done.

As a method of manufacturing a micro mechanical element, a method of selecting a sealing means when packaging in a reduced pressure atmosphere, or a substance that easily binds or adsorbs to polar molecules is used as a so-called getter inside the package. A method of providing it has been proposed (see, for example, Patent Document 1).
Micromechanical Mixer + Filtersby Ark-Chew Wong, Hao Ding, and Clark T.-C.Nguyen; Technical Digest, IEEE International Electron Device Meeting, San Francisco, California, Dec. 6-9, 1998, pp. 471-474. JP2003-133452

  However, it is difficult to solve the problem caused by the above-described charging effect only by selecting the sealing means. In other words, the selection of the sealing means makes it possible to select the main component of the gas sealed in the package as, for example, a normally used inert gas such as argon or nitrogen, but the inert gas is used for a long time. However, even if a large amount is supplied, the remaining of polar molecules in the gas phase is not always sufficiently suppressed, and even when polar molecules remain in the liquid phase or solid phase, they are vaporized over time. Therefore, there is a possibility that the device characteristics are deteriorated by polar molecules.

  In addition, the method of fixing polar molecules with a getter provided inside the package requires a heat treatment for operating the getter, and it is also necessary to separately provide an energization system for the heat treatment. It will require more labor and cost to manufacture a hermetic package where high cost exceeding its own cost is a problem.

The present invention aims to solve the above-mentioned problems, and ensure micro mechanical elements and semiconductor elements capable of ensuring excellent initial characteristics and guaranteeing device reliability, and miniaturization enabling low cost in commercialization and practical use. A method for manufacturing a mechanical element is provided.
Furthermore, this invention provides the communication apparatus provided with this micro mechanical element as a band filter.

In the micromechanical device according to the present invention, the atmosphere in the hollow formed by providing the lid on the substrate is a reducing atmosphere mainly composed of an inert gas and a reducing gas, Further, a micro driving unit connected to at least one of the substrate and the lid is provided.
Moreover, the present invention is characterized in that, in the micro mechanical element, the micro driving unit has an energization unit made of at least one of copper and aluminum.
The present invention is also characterized in that, in the micro mechanical element, the reducing gas is carbon monoxide and / or hydrogen.
In the micro mechanical element, the present invention is characterized in that the substrate is a semiconductor or an insulator.
The present invention is characterized in that in the micro mechanical element, at least one of the substrate, the lid, and the micro driving unit is subjected to a passivation process.
Further, the present invention is characterized in that, in the micro mechanical element, at least one of the substrate, the lid, and the micro driving unit is subjected to a hydrophobic treatment.
The present invention is also characterized in that, in the micro mechanical element, the micro driving unit includes a beam that is electrically driven.
Further, the present invention is characterized in that, in the micro mechanical element, the beam is a vibrator whose both ends are fixed to the substrate, and is driven by an electrode.
The present invention is also characterized in that, in the micro mechanical element, the beam is excited in a second harmonic vibration mode.
The present invention is also characterized in that, in the micro mechanical element, the beam is wider than the member for connection.
The present invention is also characterized in that, in the micro mechanical element, the reducing atmosphere is a reduced pressure atmosphere.

  A method of manufacturing a micro mechanical element according to the present invention includes a step of forming a micro drive unit on a substrate, and a step of hermetically sealing the micro drive unit with a lid in a reducing atmosphere containing a reducing gas. It is characterized by that.

A semiconductor device according to the present invention includes the micro mechanical element.
According to the present invention, in the semiconductor device, the micro mechanical element is configured as at least one of a filter, a mixer, a resonator, a signal switch, and a sensor.
Further, the present invention is characterized in that the semiconductor device is configured as a system-in-package type device or a system-on-chip type device including the micro mechanical element.

  In the communication device according to the present invention, in the communication device including a filter for limiting the band of the transmission signal and / or the reception signal, the filter by the micro mechanical element having the electrically driven beam is used as the filter. It is characterized by.

  According to the micro mechanical element according to the present invention, the micro drive unit is hermetically sealed in a reducing atmosphere mainly composed of an inert gas and a reducing gas. Even if polar molecules remain in the gas phase, liquid phase, or solid phase, avoid deterioration of the drive unit and oxidation of the current-carrying unit due to the charging effect of the polar molecules. Therefore, it is possible to sufficiently suppress the deterioration of the characteristics of the micro-driving element, and the electrodes and wiring can also be configured using inexpensive materials such as copper and aluminum, thereby reducing the manufacturing cost. it can.

Therefore, according to the semiconductor device having the micro mechanical element according to the present invention, it is possible to configure a communication device such as a filter, a mixer, a resonator, a signal switch, and a sensor having excellent initial characteristics and reliability.
In addition, for example, it is possible to avoid charging due to polar molecules adhering to the surface of the micro drive unit constituting the micro mechanical element, and to prevent an increase in stray capacitance due to oxidation of the surface of the drive unit.

  In addition, according to the method for manufacturing a micro mechanical element according to the present invention, the method includes a step of forming a micro drive unit and a step of hermetically sealing the micro drive unit with a lid in a reducing atmosphere containing a reducing gas. As a result, it is possible to manufacture a micro-driving element that can sufficiently suppress deterioration of the driving unit and oxidation of the energizing unit at a low cost.

  Furthermore, in the manufacturing method according to the present invention, as will be described later, since it is possible to further reduce the manufacturing cost by performing hermetic sealing of the reducing atmosphere at the wafer level, the micro driving element, According to the present invention, a semiconductor device having the above can be provided at a low price. Thus, the present invention can bring important and many effects.

  According to the communication device of the present invention, by using the filter by the micro mechanical element of the present invention as the bandpass filter, excellent filter characteristics can be obtained and a highly reliable communication device can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  The micro mechanical element targeted in this embodiment is a micrometer scale or nanometer scale element.

  FIG. 1 shows a first embodiment of a micromechanical element according to the present invention. The micromechanical device 1 according to the present embodiment includes an input electrode 3 and an output electrode 4 made of, for example, polysilicon and serving as a lower electrode on a substrate, which is a substrate 2 made of high resistance silicon in this example. Opposite to 3 and 4, an electrode serving as a vibrator with a space 9 interposed therebetween, that is, a micro-driving unit (so-called micro-vibrating element) 6 in which a beam 5 is formed. The input electrode 3 and the output electrode 4 function as so-called driving electrodes. The beam 5 is formed by straddling the input / output electrodes 3 and 4 in a bridge shape and integrally supporting both ends with anchor portions (support portions). In the micro-driving unit 6, when an input signal is input to the input electrode 3, the beam 5 vibrates due to electrostatic force generated between the beam 5 to which a DC bias voltage (hereinafter referred to as DC bias) is applied and the input electrode 3. An output signal corresponding to the resonance frequency of the beam is output from the output electrode 4. In this case, it is driven electrostatically, for example, excited in the second harmonic vibration mode.

  In the present embodiment, a lid 7 made of silicon is provided on the substrate 2 on which the micro-driving unit 6 is formed so as to cover the micro-driving unit 6 from above, and the substrate 2 and the lid 7 are provided. The reducing atmosphere 8 mainly composed of an inert gas and a reducing gas is enclosed in the hollow formed by the above. Thereby, the micro drive unit 6 is hermetically sealed in the reducing atmosphere 8.

Argon (Ar) or nitrogen (N ₂ ) can be used as the inert gas constituting the reducing atmosphere 8, and hydrogen (H ₂ ) or carbon monoxide (CO) can be used as the reducing gas.
In the case where hydrogen is used as the reducing gas, it is preferable to select an atmospheric composition so that the volume percentage of the inert gas is less than 4% or 74% or more from the viewpoint of ensuring safety in handling. In addition, when carbon monoxide is used as the reducing gas, it is preferable to select an atmosphere composition so that the volume percentage of the inert gas is less than 12.5% in order to ensure safety in handling.

The current-carrying parts formed on the substrate 2, that is, the wirings and electrodes connected to the input electrode 3, the output electrode 4, and the support part of the beam 5, respectively, are altered by oxidation or the like because the atmosphere is composed of a reducing gas. Therefore, for example, copper (Cu), aluminum (Al), tungsten (W), nickel (Ni), and an alloy containing these as main components should be used without using gold (Au). Can do.
Further, the beam-shaped portion of the micro drive unit 6 is usually formed wider than the connection portion with the substrate 2 and the lid body 7. In this case, it is possible to suppress a charging effect that is particularly likely to occur in the wide beam-shaped portion or a bent portion serving as a boundary between the beam-shaped portion and the connecting portion.

On the other hand, the outside of the lid body 7 may be configured by an atmosphere (hereinafter referred to as a polar atmosphere) 10 in which polar molecules are not particularly excluded as long as separation from the wiring is ensured. This is a semiconductor device having a micro mechanical element 1, for example, when it takes various device types such as SiP (system in package) and SoC (system on chip), which will be described later. The configuration shown in the drawing corresponds to the case where a hermetic package is formed at the device level during manufacturing.
Examples of polar molecules include water molecules and the like, as well as those obtained by vaporizing surfactants and resist residues used in the device manufacturing process, and organic molecules that form part fragments of the manufacturing apparatus.

  According to the micromechanical element 1 according to the first embodiment, after the hermetic sealing of the micro-driving unit 6, when polar molecules remain in the gas phase, liquid phase, or solid phase inside the package However, the progress of alteration such as oxidation is suppressed by the reducing atmosphere, and it is possible to avoid alteration of the drive unit and oxidation of the current-carrying unit due to the charging effect by polar molecules. Deterioration can be sufficiently suppressed.

FIG. 2 shows a second embodiment of the micromechanical element according to the present invention.
In this embodiment, the micromechanical element 11 according to this embodiment, which is an example in which the lower electrode and the beam are configured as a one-end support type, has an input electrode 3 serving as a lower electrode and an output on a substrate 2 similar to FIG. The electrode 4 is formed, and the micro-driving unit (the so-called micro-vibration element 6 is provided) in which the beam 5 that is supported on one end is formed to face the input / output electrodes 3 and 4 with the space 9 interposed therebetween. 5 is formed by bridging the input / output electrodes 3 and 4 in a bridge shape, and one end is integrally supported by an anchor portion (support portion), and the minute drive portion is formed on the substrate 2 on which the minute drive portion 6 is formed. A lid 7 is provided so as to cover 6 from above, and a reducing atmosphere 8 mainly composed of an inert gas and a reducing gas is enclosed in a hollow formed by the substrate 2 and the lid 7, The micro-driving unit 6 is hermetically sealed and other configurations and operations are illustrated in the figure. In is the same as that described, the parts corresponding to FIG. 1 for a repeated explanation thereof are denoted by the same reference numerals.

FIG. 3 shows a third embodiment of the micromechanical element according to the present invention.
In the micromechanical element of the present embodiment, a desired mechanical resonance frequency configured by forming a plurality of micromechanical elements 1 or 11 shown in FIGS. 1 and 2 in parallel on the substrate, in this example, the mechanical resonance frequency. A 100 MHz electrostatic drive type vibrator group will be exemplified.

  As shown in FIG. 3, the micro mechanical element 12 according to the present embodiment forms an input electrode 3 and an output electrode 4 which are lower electrodes on a substrate 2, and uses the input / output electrodes 3 and 4 as a common space 8. A plurality of beams 5 are arrayed with the beam 5 interposed therebetween, and each beam 5 has a vibrator group 21 in which the minute driving units 6 are connected in parallel as the minute driving unit 6. The input electrode 3 and the output electrode 4 are connected to a wiring on the substrate 2 outside the lid body 7 to be described later through a wiring 13 embedded in the substrate 2. And it connects to the wiring on the board | substrate 2 with which the vibrator | oscillator group 21 which consists of the several parallel micro drive part 6 was formed. A lid 7 is provided on the substrate 2 on which the vibrator group 21 including the plurality of micro-driving units 6 arranged in parallel is formed so as to cover the micro-driving unit 6 from above. The reducing atmosphere 8 mainly composed of an inert gas and a reducing gas is enclosed in the hollow formed by the above, and the vibrator group 21 is hermetically sealed.

Next, an embodiment of a method for manufacturing a micro mechanical element according to the present invention will be described. This example is an example of a method of manufacturing a micro mechanical element having the same configuration as that of FIG.
First, as shown in FIG. 4A, a substrate 2 made of high resistance silicon is prepared, and an insulating layer 31 made of a silicon oxide thin film, a silicon nitride film, and a composite film, for example, by HDP (High Density Plasma) oxidation is formed on the upper surface thereof. In this example, the film is formed to a thickness of about 200 nm.
Thereafter, a conductive layer 32 made of, for example, polycrystalline silicon (PDAS) is formed to a required thickness, in this example, about 380 nm, and a resist mask (not shown) of an embedded wiring pattern is formed. Then, dry etching is performed to remove unnecessary portions of the conductive layer 32, thereby forming a buried wiring pattern by the conductive layer 32 for bypassing the lower part of the wafer bonding pad formed in a later process and for connection to the outside. To do.

Subsequently, as shown in FIG. 4B, for example, an insulating layer 33 in which a silicon oxide thin film and silicon nitride are combined is grown, and the previously formed embedded wiring pattern 32 is backfilled. Next, after a via hole 34 for electrical connection is formed in the insulating layer 33, polycrystalline silicon (PDAS) is formed on the wiring pattern 32, and planarized by a chemical mechanical polishing (CMP) method. Then, the connection conductor 35 made of polycrystalline silicon in the via hole 34 is selectively exposed on the surface of the insulating layer 33.

The subsequent drawings of FIGS. 4C to 8B are shown by a cross-sectional structure taken along the line bb ′ of FIG. 4B. However, 31 insulating layers and 32 conductive layers in these drawings are patterned, and these films do not exist on the entire surface of the substrate. (It only shows that an upper structure is formed through the steps 31 and 32.)
Subsequently, as shown in FIG. 4C, a polycrystalline silicon (PDAS) film is formed on the entire surface, and a resist having a shape corresponding to a beam fixing base of a lower electrode and a micro-driving unit (vibrator) to be finally formed. After the mask is formed, unnecessary portions of the polycrystalline silicon (PDAS) are selectively removed by a dry etching method, and the input electrode 36, the output electrode 37, and the beam, which are the final lower electrodes made of polycrystalline silicon, are supported by the base. 38. A bonding pad portion 39 is formed.

  Subsequently, as shown in FIG. 5A, the formed input electrodes 36 and 37, the fixing base 38, and the bonding pad portion 39 are backfilled with an insulating layer 40 made of silicon oxide, and planarized by a chemical mechanical polishing method. The input / output electrodes 36 and 37, the fixing base 38 and the bonding pad portion 39 are exposed on the surface.

  Subsequently, as shown in FIG. 5B, the planarized upper surface is oxidized to a required thickness, for example, about 50 nm depending on the distance between the input / output electrodes 36 and 37 and a beam to be formed later. An insulating layer 41 is formed by additionally forming a silicon (LP-TEOS; Low Pressure Tetraethoxy Silane) film. After that, as shown in FIG. 5C, the through hole 43 that connects the beam of the micro drive unit finally obtained and the fixing base 38 and the contact through hole 43 of the bonding pad unit 39 are formed by dry etching. The remaining insulating layers 40 and 41 form an insulating layer 42 which becomes a sacrificial layer.

Subsequently, as shown in FIG. 6A, a polycrystalline silicon (PDAS) film is formed and patterned to form a beam 44, wiring (not shown) and a conductive layer 45 on the pad portion 39 by the polycrystalline silicon film. To do. Next, an Al—Si thin film is formed on the conductive layer 45 on the wiring and pad portion 39 to form a wiring pattern.
Subsequently, as shown in FIG. 6B, a metal thin film 46 made of Ti / W and a metal thin film 47 made of Au are formed on the conductive layer 45 on the bonding pad portion 39 with required thicknesses, for example, about 50 μm and 250 μm, respectively. A film is formed with a thickness of about a degree, and a wafer bonding pad shape for bonding a desired lid (wafer) is obtained by lift-off.

Subsequently, as shown in FIG. 6C, for example, an etching solution containing hydrogen fluoride is used to remove the insulating layer 42 as a sacrificial layer, and a vibration having a space gap 48 of about 50 nm between the input / output electrodes and the beam. A beam 44 is formed as a child, both ends of which are supported by the fixed base 38.
Thereafter, the input / output electrodes 36 and 37 and the beam 44 are subjected to a hydrophobic treatment by, for example, performing a hydrogen termination treatment by treatment in a gas containing hydrogen. In addition, about the other part, as mentioned above, it is preferable to perform the passivation process by SiN, for example. In this way, a micro-driving unit (substantially micro-mechanical element) 49 in which the input / output electrodes 36 and 37 and the beam 44 are disposed on the substrate 2 with the space 48 interposed therebetween is formed.

  On the other hand, as shown in FIG. 7A, for example, a silicon substrate 51 serving as a lid is prepared separately. In this silicon substrate 51, a plurality of grooves 52 corresponding to the height and area of the micro-driving unit 49 having the beam 44 produced in the previous step are formed, and silicon oxide is entirely formed on the surface of the substrate 51 by thermal oxidation. After the insulating coating 53 is formed, an insulating layer 54 made of, for example, a composite film of a silicon oxide film and a silicon nitride film by HDP (High Density Plasma) oxidation is formed to a thickness of, for example, about 200 nm to passivate the surface. Further, a metal thin film 55 made of Ti / W for bonding the lid body 7 (wafer 51) and a metal thin film 56 made of Au, for example, about 50 μm, are formed on the portion remaining in the convex shape without further groove processing. After forming a film with a thickness of about 250 μm, the film is lifted off to obtain a lid 7 having a desired shape.

Subsequently, as shown in FIG. 7B, the lid 7 and the substrate 2 having the micro-driving unit 6 formed earlier are faced in an atmosphere 57 into which a desired reducing gas is introduced, and are aligned. For example, the reducing atmosphere 57 is sealed by pressurizing at 50 kg / cm ² under the condition of 320 ° C., and the wafer is sealed. That is, the present embodiment illustrates a manufacturing method for forming a hermetic package at the wafer level.
Thereafter, although not shown, the bonded wafers are diced to obtain the micro mechanical elements 12 according to the present invention as individual chips.

  FIG. 8 shows a cross-sectional structure of the micromechanical element 12 viewed from the same direction as FIG. 4B. The input electrode 36 and the output electrode 37 are respectively connected to the embedded wiring pattern 32 and led out to the outside of the lid body 7.

  According to the method of manufacturing a micro mechanical element according to the present embodiment, the step of forming the micro drive unit 6, the step of introducing the reducing atmosphere 57 containing a reducing gas, and the reducing atmosphere 57 include the micro driving unit 6. In addition, by the hermetically sealing step, it is possible to manufacture a micro mechanical element that can sufficiently suppress the deterioration of the micro driving unit and the oxidation of the energizing unit at a low cost. Accordingly, since it is possible to select whether the hermetically sealing is performed at the wafer level or the device level, the micro mechanical element or various micro driving elements according to the present invention including the micro mechanical element, Can be provided at low cost.

9A and 9B show a fourth embodiment in which the micromechanical element 2 according to the present invention is applied to a high-frequency switch. 9A is a cross-sectional view taken along line aa ′ of FIG. 9B.
The high-frequency switch 14 according to the present embodiment forms a lower electrode 22 and a high-frequency signal line (RF signal line) 23 on the substrate 2, and one end is fixed to the substrate 2 and a contact S is formed at the tip. The beam 5 is formed and configured. At this time, the micro drive unit 6 is configured by the lower electrode 22 and the beam 5. An insulating thin film 16 is formed on the surface of the substrate 2, and a beam 5 is formed on the insulating thin film 16 via the lower electrode 22, the high-frequency signal line 23, and the drive power line 17. A ground conductor film 18 is formed on the back surface of the substrate 2.

A driving electrode thin film 19 and a nitride film 20 are laminated on both main surfaces of the conductive beam 5.
The contacts between the micro drive unit 6 and the RF signal line 23, the electrodes, the feed line, the RF signal line, and the ground plane are formed of an Al alloy thin film. The beam is formed of a SiO ₂ thin film. The insulating film 16 on the substrate is formed of a SiN / SiO ₂ composite film.
When a co-planar line is used, the ground conductor film 18 on the back surface is not necessary, but a ground conductor film is provided on the side of the high-frequency line (substrate surface). A configuration in which grounding surfaces are provided on both the back surface and the front surface is also possible.

  The distance between the electrodes is typically 1.2 μm, and the distance between the RF contact and the signal line in this case is 0.5 μm, and the pull-in phenomenon between the electrodes (usually about 2/3 of the initial distance) Projection S is provided on the beam-side RF contact as shown in the figure so that the “close” operation of the RF contact is completed before the occurrence of the event (which occurs when the interval is reduced). Further, if necessary, an (insulating) SiN thin film of about 20 nm is provided on the front and back surfaces of the beam as a protective film (on the portion excluding the contact point and the fulcrum).

  The high frequency switch 14 is driven by applying a voltage between the electrode 19 and the lower electrode 22 of the beam 5. When a predetermined voltage is applied between the driving power lines 15 and 17 between the electrode thin film 19 and the lower electrode 22 of the beam 5, the beam 5 that has been sufficiently separated from the lower electrode 22 until then is The high-frequency signal line 23 that has been placed in the “open” state due to a break in the line is brought into a conductive state, because the contact S at the tip of the beam 5 is bent by an electrostatic force between the electrode 22 and the high-frequency signal line 23. . When the driving voltage is not applied, the beam 5 returns to a state sufficiently separated from the lower electrode 22 by the restoring force of the anchor portion that also serves as the driving power line, and the signal line is in the “open” state.

In another embodiment according to the present invention, a signal filter, a mixer, a resonator, and a SiP (system in package) device module including them using the above-described micro mechanical elements 1, 12, 14 and the like. A semiconductor device such as a SoC (system on chip) device module can be configured.
According to the semiconductor device of this embodiment, since the micro vibrator having the high reliability as described above is provided, a highly reliable semiconductor device can be provided.

  The micro mechanical elements 1, 12, and 14 according to the present invention can be used as band signal filters such as a high frequency (RF) filter and an intermediate frequency (IF) filter. The present invention provides a communication apparatus that communicates using electromagnetic waves, such as a mobile phone, a wireless LAN device, a wireless transceiver, a TV tuner, and a radio tuner, by applying the filter by the micro mechanical elements 1, 12, and 14 described above. can do.

Next, a configuration example of a communication apparatus to which the filter of the above-described embodiment is applied will be described with reference to FIG.
The configuration of the transmission system will be described. I-channel transmission data and Q-channel transmission data are supplied to analog / digital converters (DACs) 201I and 201Q, respectively, and converted into analog signals. The converted signal of each channel is supplied to band pass filters 202I and 202Q to remove signal components other than the band of the transmission signal, and the outputs of the band pass filters 202I and 202Q are supplied to the modulator 210. Supply.

  The modulator 210 supplies the frequency signals corresponding to the transmission frequency supplied from the PLL (phase-locked loop) circuit 203 for transmission to the mixers 212I and 212Q via the buffer amplifiers 211I and 211Q for each channel. The signals are mixed and modulated, and both mixed signals are added by an adder 214 to form a single transmission signal. In this case, the signal phase of the frequency signal supplied to the mixer 212I is shifted by 90 ° by the phase shifter 213 so that the I channel signal and the Q channel signal are orthogonally modulated.

  The output of the adder 214 is supplied to the power amplifier 204 via the buffer amplifier 215 and amplified so as to have a predetermined transmission power. The signal amplified by the power amplifier 204 is supplied to the antenna 207 via the transmission / reception switch 205 and the high frequency filter 206, and is wirelessly transmitted from the antenna 207. The high frequency filter 206 is a band pass filter that removes signal components other than the frequency band transmitted and received by the communication apparatus.

  As a configuration of the reception system, a signal received by the antenna 207 is supplied to the high frequency unit 220 via the high frequency filter 206 and the transmission / reception switch 205. In the high frequency unit 220, the received signal is amplified by a low noise amplifier (LNA) 221 and then supplied to the band pass filter 222 to remove signal components other than the received frequency band, and the removed signal is buffer amplifier 223. To the mixer 224. Then, the frequency signals supplied from the channel selection PLL circuit 251 are mixed, a signal of a predetermined transmission channel is used as an intermediate frequency signal, and the intermediate frequency signal is supplied to the intermediate frequency circuit 230 via the buffer amplifier 225.

  The intermediate frequency circuit 230 supplies the supplied intermediate frequency signal to the band pass filter 232 via the buffer amplifier 231, removes signal components other than the band of the intermediate frequency signal, and automatically removes the removed signal. The signal is supplied to an adjustment circuit (AGC circuit) 233 to obtain a signal with a substantially constant gain. The intermediate frequency signal whose gain has been adjusted by the automatic gain adjustment circuit 233 is supplied to the demodulator 240 via the buffer amplifier 234.

  The demodulator 240 supplies the supplied intermediate frequency signal to the mixers 242I and 242Q via the buffer amplifier 241, mixes the frequency signal supplied from the intermediate frequency PLL circuit 252, and receives the received I channel signal. The component and the Q channel signal component are demodulated. In this case, the I-signal mixer 242I is supplied with a frequency signal whose signal phase is shifted by 90 ° by the phase shifter 243, and the quadrature-modulated I-channel signal component and Q-channel signal component. And demodulate.

  The demodulated I channel and Q channel signals are supplied to band pass filters 253I and 253Q via buffer amplifiers 244I and 244Q, respectively, to remove and remove signal components other than I channel and Q channel signals. The received signals are supplied to analog / digital converters (ADC) 254I and 254Q, sampled and converted into digital data, and I-channel received data and Q-channel received data are obtained.

  In the configuration described so far, each of the band pass filters 202I, 202Q, 206, 222, 232, 253I, and 253Q is used as a filter by using the micro mechanical element and the semiconductor device according to the configuration of the above-described embodiment as a filter. It can be used to limit the bandwidth.

  As described above, according to the present invention, it is possible to provide a highly reliable communication apparatus using the above-described highly reliable filter.

  Note that the method of manufacturing the micro mechanical element, the semiconductor device, and the micro mechanical element according to the present invention is not limited to this embodiment.

  For example, for the portion to which an electric field is applied such as the micro-driving unit 6 and the wiring 13 and the electrodes 3 and 4, for example, when the material is silicon (Si), it is subjected to hydrogen termination treatment and is configured by various metals. It is preferable to carry out the production by appropriately applying a hydrophobic treatment such as a passivating treatment for the portion to be treated.

In addition, the inner surface of the lid that can be covered with an insulating film and the surface of the substrate on which the micro-driving unit is not formed are smoothed as much as possible to reduce the area showing the gas adsorption activity and to charge the phenomenon. It is preferable to suppress the occurrence of.
This smoothing process can be performed by inserting a planarization step immediately after the formation of the insulating layer 33 in the embodiment of the manufacturing method described above.

Further, when the reducing atmospheres 8 and 57 are used, the inside of the space does not necessarily have to be in a reduced pressure state, but a desired high vacuum package can be obtained according to the characteristics required for the micro mechanical element.
Although omitted in the embodiment of the manufacturing method, it is generally convenient to provide the ground conductor film 18 on the back surface of the substrate after the assembly of the package is completed. In this case, a material other than the Al alloy may be used.

Further, in the third embodiment of the micro mechanical element and the semiconductor device described above, each filter is configured as a band pass filter. However, a low pass band that allows only a frequency band lower than a predetermined frequency to pass therethrough. A filter or a high-pass filter that passes only a frequency band above a predetermined frequency may be configured, and the filter according to the configuration of the other embodiment described above may be applied to these filters.
Further, the present invention is not limited to a communication device that performs wireless transmission and reception, and may be applied to a filter included in a communication device that performs transmission and reception via a wired transmission path. The present invention can be modified and changed in various ways, for example, a filter having the configuration of the above-described embodiment may be applied to a filter included in a communication device that performs only the above.

It is a schematic sectional drawing which shows the structure of an example of the micro mechanical element which concerns on this invention. It is a schematic sectional drawing which shows the structure of the other example of the micro mechanical element which concerns on this invention. It is a schematic sectional drawing which shows the structure of the other example of the micro mechanical element which concerns on this invention. FIGS. 8A to 8C are process diagrams for explaining an example of a manufacturing method of a micro mechanical element and a semiconductor device according to the present invention. FIGS. 8A to 8C are process diagrams for explaining an example of a manufacturing method of a micro mechanical element according to the present invention. FIGS. 8A to 8C are process diagrams for explaining an example of a manufacturing method of a micro mechanical element according to the present invention. A and B are process diagrams for explaining an example of a manufacturing method of a micro mechanical element according to the present invention. It is process drawing with which it uses for description of an example of the manufacturing method of the micro mechanical element which concerns on this invention. A and B are a schematic sectional view and a schematic plan view, respectively, showing the configuration of another example of the micromechanical element according to the present invention. It is a schematic diagram with which it uses for description of an example of the device module comprised by the semiconductor device by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Micro mechanical element, 2 ... Board | substrate, 3 ... Input electrode (lower electrode), 4 ... Output electrode, 5 ... Beam, 6 ... Micro drive part, 7 ... Lid, 8 ... reducing gas, 9 ... space, 10 ... polar atmosphere, 11 ... micro mechanical element, 12 ... micro mechanical element, 13 ... wiring, 14 ... High frequency switch, 16 ... insulating thin film, 17 ... driving power line, 18 ... ground conductor film, 19 ... electrode thin film, 20 ... nitride film, 21 ... vibrator group, 22 ... Lower electrode, 23 ... RF signal line (high frequency signal line), 31 ... Insulating layer, 32 ... Conductive layer, 33 ... Insulating layer, 34 ... Via hole, 35 ... Connection conductor 36 ... Input electrode 37 ... Output electrode 38 ... Fixing base 39 ... Junction pad part 40 ... Insulating layer 41 ..Insulating layer, 42 ... insulating layer, 43 ... through hole, 44 ... beam, 45 ... conductive layer, 46 ... metal thin film, 47 ... metal thin film, 48 ... Space, 49... Micro drive unit, 51... Substrate, 52 .. groove, 53 .. insulating coating, 54 .. insulating layer, 55 .. metal thin film, 56.

Claims (16)

The atmosphere in the hollow formed by providing a lid on the substrate is a reducing atmosphere mainly composed of an inert gas and a reducing gas,
A micromechanical device characterized in that in the reducing atmosphere, a micro drive unit connected to at least one of the substrate and the lid is provided. The micro mechanical element according to claim 1, wherein the micro driving unit includes an energization unit made of at least one of copper and aluminum. The micromechanical device according to claim 1, wherein the reducing gas is carbon monoxide and / or hydrogen. The micro mechanical element according to claim 1, wherein the substrate is a semiconductor or an insulator. The micromechanical device according to claim 1, wherein at least one of the substrate, the lid, and the micro-driving unit is passivated. The micro mechanical element according to claim 1, wherein hydrophobic treatment is performed on at least one of the substrate, the lid, and the micro driving unit. The micro mechanical element according to claim 1, wherein the micro driving unit includes a beam that is electrically driven. The micromechanical device according to claim 7, wherein the beam is a vibrator whose both ends are fixed to the substrate, and is driven by an electrode. The micromechanical device according to claim 7, wherein the beam is configured to be excited in a second harmonic vibration mode. The micromechanical element according to claim 1, wherein the beam is wider than the member for connection. The micromechanical element according to claim 1, wherein the reducing atmosphere is a reduced-pressure atmosphere. A method of manufacturing a micromechanical element, comprising: a step of forming a micro-driving unit on a substrate; and a step of hermetically sealing the micro-driving unit with a lid in a reducing atmosphere containing a reducing gas. . It has the micro mechanical element in any one of the said Claims 1-11. The semiconductor device characterized by the above-mentioned. The semiconductor device according to claim 13, wherein the micro mechanical element is configured as at least one of a filter, a mixer, a resonator, a signal switch, and a sensor. The semiconductor device according to claim 13, wherein the semiconductor device is configured as a system-in-package type device or a system-on-chip type device including the micro mechanical element. In a communication apparatus provided with a filter for limiting the bandwidth of a transmission signal and / or a reception signal,
A filter using the micromechanical element according to claim 7 is used as the filter.

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