JP5290911B2 - Microresonator and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a desired resonant frequency over a plurality of frequency bands or a wide frequency band by one resonator formed by MEMS (Micro Electro Mechanical System) techniques. <P>SOLUTION: The micro resonator includes: resonator movable electrodes 105 disposed separately on an interlayer dielectric 103 (substrate 101); a pair of conductive and linear resonator spring beams 108 each disposed on the same straight line while connecting one terminal to counter side surfaces of one resonator movable electrode 105; a pair of electrode terminals 109 each separately supporting the resonator spring beams 108 on the interlayer dielectric 103 and being connected to another terminal of the resonator spring beam 108; and a pair of resonator fixed electrodes 110 each being fixed in the interlayer dielectric 103 at a side of both side surfaces of the other resonator movable electrode 105. Furthermore, a rod 113 is provided while is made movable within a plane parallel to a plane of the substrate 101 while coming in contact with a side of the resonator spring beam 108. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a micro vibrator by MEMS technology and a manufacturing method thereof.

  In recent years, micromachines called MEMS (Micro Electro Mechanical System) and electronic parts incorporating MEMS have been actively developed. This MEMS is based on a manufacturing technique of a semiconductor integrated circuit in which a thin film is formed on a wafer such as a semiconductor substrate and this thin film is processed. The feature of the MEMS element is that the movable structure is configured as a part of the mechanical structure. The operation of the movable structure is performed by the Coulomb force between the electrodes provided in the fixed structure arranged to be separated from the movable structure.

  The micro-vibration element manufactured using such a MEMS technology can be integrated with other semiconductor devices, has a feature that the exclusive area of the vibration element is small, and a high Q value can be realized. . From these features, research institutes have proposed that micro-vibrators based on MEMS technology be used as RF-MEMS devices, which are wireless communication MEMS devices, and in particular as resonators for configuring filters, oscillators, mixers, etc. Has been.

  The above-described resonator will be briefly described with reference to the plan view of FIG. The resonator includes, for example, a pair of electrode terminals 609 serving as a support and a pair of coupling portions 608 coupled to the electrode terminals 609 on a substrate 601 such as a silicon substrate on which an insulating film such as an oxide film is formed. In addition, a movable electrode 605 supported on the substrate 601 by being separated by these connecting portions 608 is provided. The movable electrode 605 is disposed between a pair of fixed electrodes 610. An electrode terminal 627 is connected to the fixed electrode 610. On the side surfaces of the movable electrode 605 and the fixed electrodes 610 on both sides of the movable electrode 605 facing each other, there are provided comb-like portions arranged so that the respective comb-tooth portions enter the respective concave portions.

  Such a resonator is formed by applying an AC voltage between an electrode terminal 627 of one fixed electrode 610 and an electrode terminal 609 connected to the movable electrode 605 via a connecting portion 608, An electrostatic attractive force (Coulomb force) is generated between the movable electrode 605 and the movable electrode 605 is vibrated in the direction of the arrow in FIG. The connecting portion 608 becomes a spring beam, and the movable electrode 605 vibrates. The direction in which the movable electrode 605 vibrates is the direction in which the fixed electrode 610 is disposed as viewed from the movable electrode 605, and in this example, the direction is perpendicular to the direction in which the connecting portion 608 extends.

  At this time, a resonance phenomenon occurs when the resonance frequency determined by the spring constant of the connecting portion 608 supporting the movable electrode 605 and the mass of the movable electrode 605 matches the frequency of the input AC voltage, and the other fixed A resonance frequency is output from the electrode 610 to function as a resonator.

Japanese Patent Laid-Open No. 2005-277861

C.T.-C.Nguyen, "Frequency-Selective MEMS for Miniaturized Low-Power Communication Devices", IEEE Transactions on Microwave Theory and Techniques, Vol.47, No.8, pp.1486-1503, 1999. Gabriel M. Rebeiz, "RF-MEMS theory, design, and technology", A John Wiley & Sons Publications, 2002.

  By the way, as described above, the resonance frequency of the resonator is determined by the spring constant of the spring supported by the movable electrode and the mass of the movable electrode. For this reason, only a specific resonance frequency corresponding to the structural parameter can be obtained for the input signal, and the resonance frequency cannot be changed after the resonator is formed.

  When using a resonator as a filter, not only allows a single frequency signal to pass through, but also allows a specific frequency band to be switched from a plurality of frequency bands and allows transmission characteristics such as passing a signal over a wide band. It becomes important.

  However, as described above, most of the resonators based on the MEMS technology allow a single frequency signal to pass through the resonance frequency determined by the structural parameter as described above, and a specific frequency band is switched from a plurality of frequency bands. In addition, it is difficult to pass a signal over a wide band.

  On the other hand, a technique is known in which a plurality of resonators having different structural parameters are used, and thereby a plurality of resonance frequencies can be handled. However, in such a method, a plurality of resonators based on the above-described configuration are arranged and used, and the exclusive area increases. This contradicts the characteristic that the size reduction which is originally good at MEMS is possible and causes a problem.

  The present invention has been made to solve the above-described problems, and a desired resonance frequency over a plurality of frequency bands and a wide frequency band can be obtained with one resonator formed by the MEMS technology. The purpose is to be able to.

The microresonator according to the present invention includes a resonator movable electrode disposed on a substrate and a pair of one end disposed on the same straight line with one end connected to one opposing side surface of the resonator movable electrode. A linear resonator spring beam having electrical conductivity, a pair of electrode terminals connected to the other end of the resonator spring beam for supporting each resonator spring beam spaced apart on the substrate, and a resonator movable electrode A pair of resonator fixed electrodes fixed on the substrate on the other both side surfaces of the rod, and a rod movable in a plane parallel to the plane of the substrate so as to be in contact with the side of the resonator spring beam An electrostatic actuator that is spaced apart on the substrate and is connected to the rod to move the rod; a spring beam that is spaced apart on the substrate and is coupled to the electrostatic actuator; and An anchor that supports the substrate and an electrostatic actuator It comprises at least a fixed electrode for displacing towards the beam.

  In the microresonator, a plurality of rods may be provided for each resonator spring beam.

In addition, the method of manufacturing a microresonator according to the present invention includes a pair of resonances fixed on a substrate at two electrode terminals that are spaced apart from each other on the substrate and a line segment that connects the electrode terminals. A first step of forming a child fixed electrode, a pair of conductive linear resonator spring beams connected to each of the electrode terminals, and the resonator spring beams connected to one opposing side surface and supported. And a resonator movable electrode spaced apart on the substrate and a second rod that is movable in a plane parallel to the plane of the substrate in contact with the side of the resonator spring beam. And the resonator fixed electrode is formed on the substrate on the other side surface of the resonator movable electrode.

  In the method for manufacturing a microresonator, in the first step, a first seed layer made of metal is formed on a substrate, and a first metal pattern and a second metal pattern are formed on the first seed layer by plating. And the first seed layer is selectively etched using the first metal pattern and the second metal pattern as a mask, so that an electrode terminal comprising the first metal pattern and the first seed layer thereunder, and a second metal A resonator fixed electrode comprising a pattern and a first seed layer below the pattern is formed. In a second step, a sacrificial layer filling the electrode terminals and the sides of the resonator fixed electrode is formed on the substrate, A second seed layer made of metal is formed on the upper surfaces of the electrode terminal and the resonator fixed electrode, and a third metal pattern, a fourth metal pattern, and a fifth metal pattern are formed on the second seed layer by plating. The second seed layer is selectively etched using the third metal pattern, the fourth metal pattern, and the fifth metal pattern as a mask, and the sacrificial layer is removed. A resonator spring beam made of two seed layers, a resonator movable electrode made of a fourth metal pattern and a second seed layer below the fourth metal pattern, and a rod made of a fifth metal pattern and the second seed layer therebelow are formed.

  As described above, according to the present invention, the rod that is movable in a plane parallel to the plane of the substrate is provided in contact with the side portion of the resonator spring beam. An excellent effect is obtained that a desired resonance frequency can be obtained over a plurality of frequency bands or a wide frequency band with a single resonator formed.

It is a top view which shows the structural example of the microresonator in embodiment of this invention. It is a cross section which shows the structural example of the microresonator in embodiment of this invention. It is a cross section which shows the structural example of the microresonator in embodiment of this invention. It is a cross section which shows the structural example of the microresonator in embodiment of this invention. It is a cross section which shows the structural example of the microresonator in embodiment of this invention. It is a perspective view for demonstrating a vibrator | oscillator. It is a top view which shows the specific state of the microresonator in embodiment of this invention. It is a top view which shows the other form of the microresonator in embodiment of this invention. It is a top view which shows the other form of the microresonator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is process drawing for demonstrating the example of the manufacturing method of the micro vibrator in embodiment of this invention. It is a top view which shows the structure of a micro vibrator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, FIG. 1A is a plan view showing a configuration example of a microresonator according to an embodiment of the present invention. 1B, FIG. 1C, FIG. 1D, and FIG. 1E are sectional views showing a configuration example of the microresonator in this embodiment. 1B is a cross section taken along line bb ′ in FIG. 1A, FIG. 1C is a cross section taken along line cc ′ in FIG. 1A, FIG. 1D is a cross section taken along line dd ′ in FIG. 1A, and FIG. FIG. 1B is a cross section taken along line ee ′ of FIG. 1A.

  The microresonator in this embodiment includes an interlayer insulating layer 102 on a substrate 101 made of a semiconductor such as silicon, and an interlayer insulating layer 103 on the interlayer insulating layer 102. In addition, the resonator movable electrode 105 spaced apart on the interlayer insulating layer 103 (substrate 101) and one end thereof are connected to one opposing side surface of the resonator movable electrode 105 and are disposed on the same straight line. A pair of linear resonator spring beams 108 having conductivity and a pair of resonator spring beams 108 connected to the other ends of the resonator spring beams 108 that support the resonator spring beams 108 spaced apart on the interlayer insulating layer 103. An electrode terminal 109 and a pair of resonator fixed electrodes 110 fixed to the interlayer insulating layer 103 on the other side surface of the resonator movable electrode 105 are provided.

  Further, an electrode terminal 127 is connected to the resonator fixed electrode 110. Further, on the opposing side surfaces of the resonator movable electrode 105 and the resonator fixed electrodes 110 on both sides thereof, there are provided comb-like portions arranged so that the respective comb-tooth portions enter the respective recesses.

  The resonator movable electrode 105 can be displaced (vibrated) in the direction in which the resonator fixed electrode 110 is disposed as viewed from the resonator movable electrode 105. In this example, the vibrating method of the resonator movable electrode 105 is a direction perpendicular to the direction in which the resonator spring beam 108 extends.

  In addition, the micro vibrator according to the present embodiment includes an electrostatic actuator 106 and an electrostatic actuator 107 on the side of the resonator spring beam 108. In this example, two electrostatic actuators 106 and two electrostatic actuators 107 are provided on the sides of the resonator spring beams 108 so as to sandwich the resonator spring beams 108 on the plane of the interlayer insulating layer 103. In one resonator spring beam 108, two electrostatic actuators 106 are arranged so as to face each other, and in the other resonator spring beam 108, two electrostatic actuators 107 are arranged on this side. Opposed to each other.

  The electrostatic actuator 106 is connected to the spring beam 111, and the spring beam 111 is connected to the anchor 112. The anchor 112 is fixed on the interlayer insulating layer 103, and the spring beam 111 is supported on the fixed anchor 112 above the interlayer insulating layer 103 in a deformable state. Further, the electrostatic actuator 106 is supported above the interlayer insulating layer 103 by being connected to the spring beam 111, similarly to the spring beam 111. The electrostatic actuator 106 supported in this way is deformed (elastically deformed) by the spring beam 111, and in a direction away from the anchor 112 in a plane substantially parallel to the plane of the substrate 101, in other words, It can be displaced in the direction in which the resonator spring beam 108 is disposed as viewed from the anchor 112.

  In addition, the electrostatic actuator 106 includes a rod 113 at a side surface facing the coupling side of the spring beam 111, in other words, at the center of the spring beam 111 on the resonator spring beam 108 side. The rod 113 has a tapered tip. A fixed electrode 115 is formed on the rod 113 side of the electrostatic actuator 106 at a predetermined distance. In the present embodiment, two fixed electrodes 115 are provided on both sides of the rod 113 so as to face the side of the electrostatic actuator 106. The electrostatic actuator 106 and the fixed electrode 115 have comb teeth 114 and comb teeth 115a on their opposing side surfaces, and are arranged so that the respective comb teeth enter the recesses between the respective comb teeth. Has been.

  Further, two fixed electrodes 115 provided for one electrostatic actuator 106 are connected to an interlayer wiring 117 formed under the interlayer insulating layer 103 through a connection hole 118. The interlayer wiring 117 is connected to the drive electrode terminal 116. Therefore, the two fixed electrodes 115 are connected to the drive electrode terminal 116.

  The electrostatic actuator 107 is connected to the spring beam 119, and the spring beam 119 is connected to the anchor 120. The anchor 120 is fixed on the interlayer insulating layer 103, and the spring beam 119 is supported by the fixed anchor 120 above the interlayer insulating layer 103 in a deformable state. Further, the electrostatic actuator 107 is supported above the interlayer insulating layer 103 by being connected to the spring beam 119, similarly to the spring beam 119. The electrostatic actuator 107 supported in this way is deformed (elastically deformed) by the spring beam 119, so that the direction away from the anchor 120 in a plane substantially parallel to the plane of the substrate 101, in other words, It can be displaced in the direction in which the resonator spring beam 108 is disposed as viewed from the anchor 120.

  In addition, the electrostatic actuator 107 includes a rod 121 at a side surface facing the coupling side of the spring beam 119, in other words, at the center of the spring beam 119 on the resonator spring beam 108 side. The rod 121 has a tapered tip. A fixed electrode 123 is formed on the rod 121 forming side of the electrostatic actuator 107 with a predetermined distance. In the present embodiment, two fixed electrodes 123 are provided on both sides of the rod 121 so as to face the side of the electrostatic actuator 107. Moreover, the electrostatic actuator 107 and the fixed electrode 123 are each provided with a comb tooth portion 122 and a comb tooth portion 123a on the opposing side surfaces, and the comb tooth portions are inserted into the recesses between the respective comb teeth. Has been.

  Further, two fixed electrodes 123 provided for one electrostatic actuator 107 are connected to an interlayer wiring 125 formed under the interlayer insulating layer 103 through a connection hole 126. The interlayer wiring 125 is connected to the drive electrode terminal 124. Therefore, the two fixed electrodes 123 are connected to the drive electrode terminal 124. The above configuration is the same as that of the electrostatic actuator 106 described above.

  Next, the operation of the microresonator will be described. First, the operation of the resonator by the resonator movable electrode 105 will be described. In the resonator movable electrode 105, when an AC voltage is applied between one electrode terminal 127 and the electrode terminal 109, an electrostatic attractive force is generated between the resonator movable electrode 105 and the resonator fixed electrode 110. When the frequency of the AC voltage matches the mechanical natural frequency of the microresonator, a resonance phenomenon occurs and the resonator movable electrode 105 vibrates. When the microresonator is used as a filter, a signal corresponding to the mechanical natural frequency of the microresonator can be extracted from the other electrode terminal 127 by applying an external electric signal as an AC voltage. The mechanical natural frequency of the microresonator at this time can be expressed by the following equation.

  In the above equation (1), k is the spring constant of the resonator spring beam 108, and m is the mass of the resonator movable electrode 105.

  Next, in the microresonator according to the present embodiment, consider obtaining the spring constant of the resonator spring beam 108 by calculation. As a calculation example, the spring constant of the spring beam 202 having the dimensions shown in the perspective view of FIG. 2 is fixed when both ends are fixed to the fixing portion 201 and elastically deformed by applying a force in the direction of the arrow in the figure. Calculate The spring beam 202 supports the movable part 203. A calculation formula for obtaining the spring constant k in such a structure is shown in Non-Patent Document 2, and can be obtained by the following formula (2).

  In the above equation (2), E is the Young's modulus of the material constituting the spring beam 202, w is the width of the spring beam 202 (cross section width), t is the thickness of the spring beam 202 (cross section height), and l is the spring. This is the length of the beam 202. A desired mechanical natural frequency can be obtained by setting these parameters.

  Next, the operation of the electrostatic actuator 106 will be described. When a DC voltage is applied between the anchor 112 and the drive electrode terminal 116, the electrostatic actuator 106 is electrostatically connected between the electrostatic actuator 106 (comb portion 114) and the fixed electrode 115 (comb portion 115a). Attraction is generated. This electrostatic attractive force is a force that pulls the electrostatic actuator 106 toward the fixed electrode 115. When this electrostatic attractive force is applied to the electrostatic actuator 106, the spring beam 111 is deformed and the electrostatic actuator 106 is displaced toward the fixed electrode 115.

  As a result, the rod 113 moves in the direction of the resonator spring beam 108, and for example, the tip portion of the rod 113 contacts the side portion of the resonator spring beam 108. Further, by interrupting the application of the DC voltage to the drive electrode terminal 116 described above, the electrostatic actuator 106 returns to the initial position by the restoring force of the spring beam 111, so that the rod 113 is also more than the resonator spring beam 108. Separate.

  Therefore, the microresonator according to the present embodiment includes the rod 113 that is movable in a plane parallel to the plane of the substrate 101 in contact with the side portion of the resonator spring beam 108. . These operations are the same in the electrostatic actuator 107. In the present embodiment, by operating the electrostatic actuator 106 and the electrostatic actuator 107, the tip of the rod 113 and the tip of the rod 121 are brought into contact with the resonator spring beam 108.

  For example, by operating the two electrostatic actuators 106 and the two electrostatic actuators 107, as shown in the plan view of FIG. 3A, the center portion of one resonator spring beam 108 is caused by the tips of the two rods 113. The center portion of the other resonator spring beam 108 can be swallowed by the tip portions of the two rods 121. By doing in this way, the spring length l shown by Formula (2) in the resonator spring beam 108 changes. Thus, in the microresonator according to the present embodiment, the mechanical natural frequency can be changed.

  Further, as shown in the plan view of FIG. 3B, the electrostatic actuator 106 (rod 113) and the electrostatic actuator 107 (rod 121) may be disposed close to the electrode terminal 109. In this case, when the electrostatic actuator 106 and the electrostatic actuator 107 are operated, the spring length l indicated by the expression (2) in the resonator spring beam 108 changes smaller than that in the above case. For this reason, in this example, the mechanical natural frequency of the microresonator represented by the equation (1) can be slightly changed. Thus, the amount of change in the mechanical natural frequency of the microresonator can be controlled by the arrangement of the electrostatic actuator (rod).

  Next, another microresonator of the present invention will be described. FIG. 4 is a plan view showing another configuration example of the microresonator according to the embodiment of the invention. In the microresonator shown in FIG. 4, electrostatic actuators 401 and 402 are disposed with one resonator spring beam 108 interposed therebetween, and electrostatic actuators 403 and 404 are disposed with the other resonator spring beam 108 interposed therebetween. It is installed. The electrostatic actuators 401, 402, 403, and 404 are the same as the electrostatic actuators 106 and 107 described above.

  By driving these electrostatic actuators 401, 402, 403, and 404 independently, a plurality of mechanical natural vibration frequencies can be obtained. For example, when all the electrostatic actuators are OFF, the spring length l indicated by the expression (2) in the resonator spring beam 108 is the longest. Further, when the electrostatic actuators 402 and 403 are ON and the electrostatic actuators 401 and 404 are OFF, the spring length l indicated by the expression (2) in the resonator spring beam 108 can be minimized. Further, when the electrostatic actuators 401 and 404 are ON and the electrostatic actuators 402 and 403 are OFF, the spring length l shown by the equation (2) in the resonator spring beam 108 is set to an intermediate value between the two states described above. It can be a length.

  In the above description, for example, the resonator spring beam 108 is sandwiched by two (plural) electrostatic actuators 106 (rods 113). However, the present invention is not limited to this, and one of the resonator spring beams 108 is not limited thereto. One electrostatic actuator 106 (rod 113) may be disposed on the side. The same applies to the side where the electrostatic actuator 107 is disposed.

  Also, when two electrostatic actuators are provided on one resonator spring beam 108, it is not necessary to provide two sets of electrostatic actuators so as to sandwich the resonator spring beam 108. For example, in one resonator spring beam 108, on one side, an electrostatic actuator is disposed near the resonator movable electrode 105 so that the rod can be contacted, and on the other side, an electrode terminal 109 is provided. By disposing the electrostatic actuator near the position so that the rod can come into contact with each other, one resonator spring beam 108 may be arranged so that the two rods can come into contact with each other.

  However, the two electrostatic actuators are arranged so as to sandwich the resonator spring beam 108, and the two rods arranged opposite to each other are in contact with each other so as to sandwich the resonator spring beam 108 at the same position, so that the resonator spring beam 108 is sandwiched. The spring length l shown by the equation (2) in can be controlled more stably.

  In the above description, the opposing surfaces of the fixed electrode and the movable electrode for applying electrostatic attraction are comb-like, but the present invention is not limited to this, and may be a flat shape. However, by adopting a comb-teeth shape, the area where the fixed electrode and the movable electrode face each other can be widened, and a stronger electrostatic attraction can be provided while being installed in a limited width. It becomes like this.

  Next, a method for manufacturing the microresonator in the above-described embodiment will be described with reference to FIGS. 5A to 5L. 5A to 5L show states (cross sections) in respective steps corresponding to the cross section taken along line bb 'in FIG. 1A.

  First, an interlayer insulating layer 102 made of, for example, silicon oxide is formed on a substrate 101 made of, for example, a semiconductor such as silicon. Note that the substrate 101 may include a semiconductor integrated circuit including a plurality of transistors, resistors, capacitors, wirings, and the like. For example, the wiring of the integrated circuit and the microresonator in this embodiment are electrically connected. A contact hole or the like may be formed at a predetermined location of the interlayer insulating layer 102.

  Next, as shown in FIG. 5A, the first seed layer 501 is formed on the interlayer insulating layer 102. The first seed layer 501 may be a laminated film of a titanium layer having a thickness of about 0.1 μm and a gold layer having a thickness of about 0.1 μm formed thereon. These may be formed by sputtering or vapor deposition.

  When the first seed layer 501 is formed as described above, a resist is applied thereon to form a resist film, and the formed resist film is patterned by a known lithography technique to provide an opening at a desired location. Form a pattern. The resist pattern is formed with a film thickness of about 3 μm, for example. Next, a gold pattern, for example, is formed by plating on the first seed layer 501 exposed at the opening of the formed resist pattern. For example, the plating film is formed with a film thickness of about 0.5 μm. Thereafter, by removing the resist pattern, the first metal pattern 502 and the second metal pattern 503 are formed on the first seed layer 501 as shown in FIG. 5B. The first metal pattern 502 and the second metal pattern 503 are formed with a film thickness of about 0.5 μm.

  Next, using the first metal pattern 502 and the second metal pattern 503 as a mask, the first seed layer 501 is removed by etching, and as shown in FIG. 5C, the interlayer wiring 117 and the interlayer wiring are formed on the interlayer insulating layer 102. It is assumed that the wiring 125 is formed. The interlayer wiring 117 includes a first metal pattern 502 and a first seed layer 501 below the first metal pattern 502, and the interlayer wiring 125 includes a second metal pattern 503 and a first seed layer 501 below the second metal pattern 503. Become.

  In the selective etching of the first seed layer 501, for example, the upper gold layer of the first seed layer 501 may be wet etched using an aqua regia etchant composed of nitric acid and hydrochloric acid. The titanium layer under the first seed layer 501 exposed by this etching can be removed by wet etching using a hydrogen fluoride aqueous solution.

  Next, as illustrated in FIG. 5D, the interlayer insulating layer 103 is formed on the interlayer insulating layer 102 including the formed interlayer wiring 117 and the interlayer wiring 125. For example, a silicon oxide film is deposited by plasma CVD, and the formed silicon oxide film is planarized by using a known constant-speed etchback method. Thereby, the interlayer insulating layer 103 having a layer thickness of about 1 μm can be formed with the surface being flattened.

  Next, as shown in FIG. 5E, a connection hole 118 and a connection hole 126 reaching the interlayer wiring 117 and the interlayer wiring 125 are formed in the interlayer insulating layer 103. For example, when the interlayer insulating layer 103 is patterned by a known lithography technique and etching technique to form a through hole penetrating the interlayer wiring 117 and the interlayer wiring 125, the connection hole 118 and the connection hole 126 are obtained.

  Next, as shown in FIG. 5F, a second seed layer 504 is formed on the interlayer insulating layer 103 including the formed connection hole 118 and connection hole 126, and a selective plating method using a resist pattern is formed thereon. Thus, a third metal pattern 505, a fourth metal pattern 506, a fifth metal pattern 507, a sixth metal pattern 508, and a seventh metal pattern 509 are formed. The second seed layer 504 may be formed in the same manner as the first seed layer 501.

  The third metal pattern 505, the fourth metal pattern 506, the fifth metal pattern 507, the sixth metal pattern 508, and the seventh metal pattern 509 are formed in the same manner as the first metal pattern 502 and the second metal pattern 503. That's fine. For example, the third metal pattern 505, the fourth metal pattern 506, the fifth metal pattern 507, the sixth metal pattern 508, and the seventh metal pattern 509 have a resist pattern film thickness for selective plating of about 20 μm and are plated films May be formed to a thickness of about 10 μm. The third metal pattern 505 is shown not on a cross section but on a side surface.

  Next, using the third metal pattern 505, the fourth metal pattern 506, the fifth metal pattern 507, the sixth metal pattern 508, and the seventh metal pattern 509 as a mask, the second seed layer 504 is removed by etching and separated. As shown in FIG. 5G, a fixed electrode lower portion 1151, a drive electrode terminal 116, an electrode terminal lower portion 1091, a fixed electrode lower portion 1231, and a drive electrode terminal 124 are formed on the interlayer insulating layer 103. The fixed electrode lower portion 1151 includes a fourth metal pattern 506 and a second seed layer 504 below the fourth metal pattern 506, and becomes a part of the fixed electrode 115. The drive electrode terminal 116 includes a fifth metal pattern 507 and a second seed layer 504 below the fifth metal pattern 507.

  The fixed electrode lower portion 1231 includes a sixth metal pattern 508 and a second seed layer 504 below the sixth metal pattern 508, and becomes a part of the fixed electrode 123. The drive electrode terminal 124 includes a seventh metal pattern 509 and a second seed layer 504 below the seventh metal pattern 509. The electrode terminal lower portion 1091 includes a third metal pattern 505 and a second seed layer 504 below the third metal pattern 505, and becomes a part of the electrode terminal 109. In FIG. 5G, the electrode terminal lower portion 1091 is shown not on a cross section but on a side surface. Further, in other regions on the interlayer insulating layer 103 not shown in FIG. 5G, a lower portion to be the electrode terminal 127 and a lower portion to be the anchor 112 and the anchor 120 are simultaneously formed.

  Next, as shown in FIG. 5H, a sacrificial layer is formed on the interlayer insulating layer 103 so as to fill in the space between the fixed electrode lower part 1151, the drive electrode terminal 116, the electrode terminal lower part 1091 and the fixed electrode lower part 1231. 510 is formed. The upper surfaces of the fixed electrode lower portion 1151, the drive electrode terminal 116, the electrode terminal lower portion 1091 and the fixed electrode lower portion 1231 are exposed. For example, a sacrificial layer 510 is formed by applying a photosensitive organic resin made of PBO (polybenzoxazole) on the interlayer insulating layer 103 to form a coating film, and patterning the formed coating film by a known lithography technique. Can be formed. In the patterning process for forming the sacrificial layer 510, pre-baking for heating the coating film to 120 ° C. is performed for 4 minutes as a pre-process, and after the patterning, the heat treatment is performed at 310 ° C., and the organic resin of the formed pattern is thermally cured. State. As the photosensitive organic resin, CRC8300 manufactured by Sumitomo Bakelite Co., Ltd. can be used. In FIG. 5H and FIGS. 5I to 5K described below, the electrode terminal lower portion 1091 whose side surface is shown in FIG. 5G is not shown because it is buried in the sacrificial layer 510.

  Next, as shown in FIG. 5I, the first seed layer 501 is made similar to the sacrificial layer 510, the fixed electrode lower portion 1151, the drive electrode terminal 116, the electrode terminal lower portion 1091, and the fixed electrode lower portion 1231. It is assumed that three seed layers 511 are formed.

  Next, by selective plating using a resist pattern, as shown in FIG. 5J, the eighth metal pattern 512, the ninth metal pattern 513, the tenth metal pattern 514, the eleventh metal pattern are formed on the third seed layer 511. A metal pattern 515, a twelfth metal pattern 516, a thirteenth metal pattern 517, and a fourteenth metal pattern 518 are formed. These metal patterns may be formed in the same manner as the first metal pattern 502 and the second metal pattern 503 described above. For example, for these patterns, the resist pattern for selective plating may have a thickness of about 40 μm, and the plating film may be formed to a thickness of about 25 μm. Note that the twelfth metal pattern 516 has a side surface instead of a cross section.

  Next, the third metal pattern 512, the ninth metal pattern 513, the tenth metal pattern 514, the eleventh metal pattern 515, the twelfth metal pattern 516, the thirteenth metal pattern 517, and the fourteenth metal pattern 518 are used as a mask. The seed layer 511 is removed by etching, and as shown in FIG. 5K, the fixed electrode 115 and the fixed electrode 123 are formed on the interlayer insulating layer 103, and the resonator movable electrode 105, A rod 113 (electrostatic actuator 106), a rod 121 (electrostatic actuator 107), a resonator spring beam 108, and an electrode terminal upper portion 1092 are formed. The electrode terminal upper part 1092 is embedded in the sacrificial layer 510 and stacked on the electrode terminal lower part 1091 which is not shown in FIG. 5K. The electrode terminal upper portion 1092 is shown not on a cross section but on a side surface.

  Next, by removing the sacrificial layer 510, as shown in FIG. 5L, an electrode terminal 109, a fixed electrode 115, a drive electrode terminal 116, a fixed electrode 123, and a drive electrode terminal 124 are formed on the interlayer insulating layer 103. Thus, the resonator spring beam 108 supported by the electrode terminal 109 is formed, and the rod 113 and the rod 121 are formed. Although not shown, the electrostatic actuator 106 and the electrostatic actuator 107, the resonator fixed electrode 110, the spring beam 111, the spring beam 119, the anchor 112, the upper portion of the anchor 120, and the like are formed at the same time. For example, ozone can be removed by applying ozone to the sacrificial layer 510 using an ozone asher device.

  Further, it goes without saying that other micro vibrators such as the micro vibrator described with reference to FIG. 4 can be similarly manufactured by the manufacturing method according to the above description using FIGS. 5A to 5L. Thus, according to the manufacturing method described above, each structure constituting the micro-vibrator is manufactured by a plating method, and thus can be manufactured at a low temperature. For this reason, even when a microresonator is manufactured as a subsequent step of a known semiconductor integrated circuit manufacturing process, the already formed semiconductor integrated circuit is not damaged by the manufacture of the microresonator.

  In the manufacturing method described above, gold is plated. However, the present invention is not limited to this, and copper, nickel, or the like may be used as a plating material. In the case of copper or nickel, the above-described upper seed layer may be the same as the plating material.

  DESCRIPTION OF SYMBOLS 101 ... Board | substrate, 102 ... Interlayer insulation layer, 103 ... Interlayer insulation layer, 105 ... Resonator movable electrode, 106 ... Electrostatic actuator, 107 ... Electrostatic actuator, 108 ... Resonator spring beam, 109 ... Electrode terminal, 110 ... Resonance Child fixed electrode, 111 ... Spring beam, 112 ... Anchor, 113 ... Rod, 114 ... Comb portion, 115 ... Fixed electrode, 115a ... Comb portion, 116 ... Drive electrode terminal, 117 ... Interlayer wiring, 118 ... Connection hole, DESCRIPTION OF SYMBOLS 119 ... Spring beam, 120 ... Anchor, 121 ... Rod, 122 ... Comb tooth part, 123 ... Fixed electrode, 123a ... Comb tooth part, 124 ... Drive electrode terminal, 125 ... Interlayer wiring, 126 ... Connection hole, 127 ... Electrode terminal .

Claims (3)

A resonator movable electrode spaced apart on the substrate;
A pair of conductive linear resonator spring beams having one end connected to one opposite side surface of the resonator movable electrode and arranged on the same straight line;
A pair of electrode terminals connected to the other end of the resonator spring beam for supporting each resonator spring beam spaced apart on the substrate;
A pair of resonator fixed electrodes fixed on the substrate on both sides of the other side of the resonator movable electrode;
A rod that is movable in a plane parallel to the plane of the substrate in contact with the side of the resonator spring beam ;
An electrostatic actuator that is spaced apart on the substrate and is coupled to the rod to move the rod;
A spring beam spaced apart on the substrate and connected to the electrostatic actuator;
An anchor supporting the spring beam on the substrate;
A microresonator comprising at least a fixed electrode for displacing the electrostatic actuator toward the resonator spring beam . The microresonator according to claim 1, wherein
A micro-vibrator comprising a plurality of the rods for each of the resonator spring beams. A first step of forming a pair of resonator fixed electrodes fixed on the substrate at positions sandwiching two electrode terminals respectively spaced apart on the substrate and a line segment connecting these electrode terminals;
A pair of conductive linear resonator spring beams connected to each of the electrode terminals, and connected to and supported on one opposing side surface of the resonator spring beams and spaced apart on the substrate And a second step of forming a rod movable in a plane parallel to the plane of the substrate in a state in which the resonator movable electrode is in contact with a side portion of the resonator spring beam.
The resonator fixed electrode is formed on the substrate on both sides of the resonator movable electrode ,
In the first step,
Forming a first seed layer made of metal on the substrate;
Forming a first metal pattern and a second metal pattern on the first seed layer by plating;
By selectively etching the first seed layer using the first metal pattern and the second metal pattern as a mask, the electrode terminal composed of the first metal pattern and the first seed layer therebelow, and the first Forming the resonator fixed electrode comprising two metal patterns and the first seed layer under the two metal patterns;
In the second step,
Forming a sacrificial layer on the substrate to fill the side of the electrode terminal and the resonator fixed electrode;
Forming a second seed layer made of metal on the sacrificial layer, the electrode terminal, and the upper surface of the resonator fixed electrode;
Forming a third metal pattern, a fourth metal pattern, and a fifth metal pattern on the second seed layer by plating;
The second seed layer is selectively etched using the third metal pattern, the fourth metal pattern, and the fifth metal pattern as a mask, and the sacrificial layer is removed, thereby removing the third metal pattern and the lower layer. The resonator spring beam composed of the second seed layer, the fourth metal pattern and the resonator movable electrode composed of the second seed layer below, and the fifth metal pattern and the second seed below the fourth metal pattern. A method of manufacturing a microresonator, comprising forming the rod made of a layer .

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