JP2007160435A - Semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve yield of either a semiconductor device including MEMS element or MEMS element by restraining the occurrence of sticking in the manufacturing process of the MEMS element. <P>SOLUTION: The MEMS element 1 is constructed by a substrate 2, an insulating film 3 formed on the principal surface of the substrate 2, a deformable structure 4, which is formed on the upper part of the insulating film 3 and shaped like a non-planar projection to the principal surface of the substrate 2 in the stationary state, and an electrode 6 formed on a part of the structure 4 through an insulating film 5, whereby the occurrence of sticking in the manufacturing process is restrained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor device and a manufacturing technology thereof, and more particularly to a semiconductor device including a MEMS (Micro-Electro-Mechanical Systems) element and a technology effective when applied to the manufacturing thereof.

  With the progress of semiconductor process technology and micromachining technology (so-called MEMS technology), new functional devices in which CMOS (Complementary Metal Oxide Semiconductor) circuits and MEMS elements are fused are becoming widespread. For example, in a physical sensor, there is a sensor LSI (Large Scale Integration) embedded device in which a peripheral logic part is configured by a CMOS circuit manufactured by a semiconductor process technology and a sensor movable part is configured by a MEMS element manufactured by a MEMS technology.

  For example, a supercritical substance composed of carbon dioxide in which at least one of ammonium hydroxide, alkanolamine, fluorinated amine and hydrofluoric acid is used as a solubilizing agent and the solubilizing agent is added in a concentration range of 0.1 to 2 mol%. A surface treatment method for treating a surface on which a structure is formed with a liquid is disclosed (for example, see Patent Document 1).

  In addition, a movable part such as an actuator arranged partly fixed on a semiconductor substrate (hereinafter simply referred to as a substrate), a structure such as a control electrode provided on the substrate close to the movable part, and at least movable A MEMS element including a coating made of fluorocarbon formed on the surface of a portion and a structure is disclosed (for example, see Patent Document 2).

  Further, by forming a large number of recesses and recesses having a width of 0.01 μm or more and 0.1 μm or less on at least one of the surfaces where the fixed electrode and the movable electrode of the acceleration sensor face each other, A technique is disclosed in which sticking is difficult to occur both in the process and in use by reducing the contact area with the movable electrode and increasing the hydrophobicity of the silicon surface (see, for example, Patent Document 3).

In addition, a sacrificial layer is formed on the polysilicon film, and the sacrificial layer is removed by a vapor layer etching method to prevent generation of a residue, and a sticking phenomenon that occurs when the upper structure sinks into the space due to the sacrificial layer removal. A technique for preventing this is disclosed (see, for example, Patent Document 4).
JP 2005-34843 A JP 2004-130449 A Japanese Patent Laid-Open No. 11-340477 JP-A-10-107339

  When manufacturing the above-described sensor LSI mixed type device, the processing accuracy in the horizontal direction with respect to the surface of the semiconductor wafer in the sensor movable portion can be realized by the processing accuracy of the semiconductor process. However, with respect to the processing in the direction perpendicular to the surface of the semiconductor wafer in the sensor movable part, the manufacturing process unique to the MEMS technology in which the sacrificial film is removed to create a cavity, which could not occur in the manufacturing using the semiconductor process technology, is as follows. There are such challenges.

  In the manufacturing process of the MEMS element, a wet etching method or a dry etching method is adopted for manufacturing a three-dimensional structure of an actuator (mechanism for turning on and off the MEMS element). Regardless of the etching method, the actuator is immersed in the liquid by treatment with an etching solution or liquid cleaning. For this reason, in a drying process or the like for removing the liquid, the actuator may be attracted to the substrate by the surface tension of the liquid remaining between the actuator and the substrate, and the central portion of the actuator may come into contact with the substrate. Even after the remaining liquid is completely dried and removed, the actuator and the substrate remain in contact with each other, causing the MEMS element to malfunction. This phenomenon is called sticking (sticking), and means for eliminating sticking has not been established yet, which is a fatal failure factor of the MEMS element.

  An object of the present invention is to provide a technology capable of suppressing the occurrence of sticking in the manufacturing process of a MEMS element and improving the yield of the MEMS element or a semiconductor device including the MEMS element.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  A semiconductor device according to the present invention includes an insulating film formed on a substrate, a deformable structure that is partially fixed on the insulating film and has a non-planar convex shape with respect to the substrate when in a stationary state, A MEMS element including an electrode formed on a part of the structure via an insulating film is included.

  A method of manufacturing a semiconductor device according to the present invention includes a step of sequentially forming a first insulating film and a sacrificial film on a substrate, and a resist pattern is formed on the sacrificial film, and then heat treatment is performed so that the surface of the resist pattern is on the surface. A step of processing into a convex bow shape, a step of etching the sacrificial film using the resist pattern as a mask to form a sacrificial film pattern having a convex bow shape on the surface, and a sacrifice after removing the resist pattern Processing the conductor film formed on the film pattern to form a structure, and removing the sacrificial film pattern, and then forming an electrode on a part of the structure via the second insulating film Is.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  Since the occurrence of sticking in the manufacturing process of the MEMS element can be suppressed, the yield of the MEMS element or a semiconductor device including the MEMS element can be improved.

  In the present embodiment, when referring to the number of elements, etc. (including the number, numerical value, quantity, range, etc.), unless otherwise specified, the case is clearly limited to a specific number in principle, etc. It is not limited to the specific number, and it may be more or less than the specific number. Further, in the present embodiment, the constituent elements (including element steps and the like) are not necessarily essential unless particularly specified and apparently essential in principle. Yes. Similarly, in this embodiment, when referring to the shape, positional relationship, etc. of the component, etc., the shape, etc. substantially, unless otherwise specified, or otherwise considered in principle. It shall include those that are approximate or similar to. The same applies to the above numerical values and ranges.

  Further, in all drawings for explaining the present embodiment, parts having the same function are denoted by the same reference numerals, and repeated explanation thereof is omitted. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a cross-sectional view of a main part of the MEMS element according to the first embodiment.

  The MEMS element 1 includes a semiconductor substrate (hereinafter referred to as a substrate) 2, an insulating film 3 formed on the main surface of the substrate 2, and a main surface of the substrate 2 in a stationary state formed on the insulating film 3. On the other hand, a deformable structure 4 having a non-planar convex shape is provided, and an electrode 6 is provided on the structure 4 via an insulating film 5. As described above, when the structure 4 is in a non-planar convex shape with respect to the main surface of the substrate 2 in the stationary state, the manufacturing process is performed even when the gap between the insulating film 3 and the structure 4 is narrow. Sticking can be suppressed.

  Next, the reason why the effect of suppressing sticking is obtained in the MEMS element according to the first embodiment will be described in detail with reference to FIGS.

  FIG. 2 is a schematic view of a beam with both ends fixed as viewed from the side. FIG. 2A shows the shape of the beam in the initial state where no force is applied, and FIG. 2B shows the shape of the beam when the force is applied.

  When no force such as internal stress, thermal stress, or gravity is applied, the beam in the initial state in which both ends are fixed has a straight bar shape A1 represented by a broken line in FIG.

  Here, a beam is applied such that a load is applied from the end point in the direction in which the beam is stretched (hereinafter referred to as the horizontal direction), or a horizontal force is generated inside the beam due to a change in the ambient temperature where the beam is placed. Suppose a scene where some kind of power is applied. When the magnitude of the force f is weak, the beam undergoes a shape change that is compressed only in the horizontal direction. However, when the magnitude f of the force exceeds a certain value, the shape of the beam changes abruptly, and becomes a bow shape represented by a solid line in FIG. This phenomenon is called buckling deformation and occurs when the length of the beam is larger than the cross-sectional dimension of the beam.

  If both ends of the beam are fixed and there is no anisotropy in the direction perpendicular to the horizontal direction (hereinafter referred to as the vertical direction) of the force applied to the inside of the beam, it will protrude upward due to buckling It cannot be predicted whether it will be A2 or the downward convex shape A3. That is, when it is desired to control the direction of deformation of the beam due to buckling, it is necessary to take measures such as preliminarily applying the internal stress of the beam or providing a support rod in a direction in which it is not desired to be deformed.

  FIG. 3A is a schematic view of the beam with both ends fixed as viewed from the side, and shows the shape of the beam when a load F is applied from the outside in a direction perpendicular to the central point of the beam. FIG. 3B is a graph showing the result of calculating the relationship between the load F applied in the vertical direction to the central point of the beam in FIG. 3A and the deformation amount z in the vertical direction of the beam. The load F and the vertical deformation amount z of the beam are shown in arbitrary units. Further, the central points M0, M1, and M2 shown in FIG. 3A correspond to the central points M0, M1, and M2 shown in FIG.

  Assuming that the initial beam is not subjected to any force such as internal stress, thermal stress, or gravity, the beam in the initial state with both ends fixed is a straight bar represented by a broken line in FIG. Shape B1 is obtained. However, if a weight F in the vertical direction is applied to the center point of the beam from the outside downward, the beam is deformed to become an upward convex shape B2, and if the weight F is further increased, it will be higher than the upward convex shape B2. It is deformed into a convex shape B3 with a high bending rate.

  As shown in FIG. 3B, when the force acting on the central points M0, M1, and M2 of the beam is weak, the motion of the beam is non-linear like the displacement from the central point M0 to the central point M1. . However, when the force acting on the central points M0, M1, and M2 of the beam is strong, the movement of the beam is linear like the displacement from the central point M1 to the central point M2. That is, in the movable part of the MEMS element that uses the vertical movement of the beam fixed at both ends, the drive range aimed at the nonlinear effect depends on the magnitude of the acting force, regardless of the kind of acting force. There is a driving range aimed at the linear effect. In FIG. 3A, the beam is schematically represented by a line. However, the same can be said for a multimorph structure including a combination of a plurality of materials.

  FIG. 4 is a schematic view of a beam having both ends fixed, the initial internal stress is not zero at the temperature T0, and the length is larger than the cross-sectional area dimension, as viewed from the side.

  As shown in FIG. 4, since the internal stress of the beam at temperature T0 is not zero, the beam has a convex shape C1 that is bent upward. If the ambient temperature at which the beam is placed becomes T1 higher than the above temperature T0, the thermal expansion of the material forming the beam acts in the direction in which the bending increases, and the shape of the beam changes. The convex shape C2 has a higher bending rate than the upward convex shape C1. In this way, if the beam is previously bent, it is possible to control the direction of displacement when a load causing buckling such as a thermal expansion effect due to external force or temperature change is applied to the beam. .

  In order to bend the beam in the opposite direction from the direction once displaced, additional mechanical action is required, and the greater the amount of deformation, the greater the force required to return to the original shape. Become. In other words, in the structure of the beam with both ends fixed, when there is no force acting on the inside of the beam such as initial internal stress, (1) the displacement direction is not unique when the acting force causing buckling is applied, ( 2) Depending on the magnitude of the acting force causing buckling, there are a region where the amount of displacement depends nonlinearly on the acting force and a region where the amount of displacement depends linearly on the acting force. (3) The larger the amount of displacement, It can be said that the force required to return the beam to its original position is large.

  Therefore, if the non-planar convex structure 4 is formed in advance on the main surface of the substrate 2 as in the MEMS element 1 of FIG. 1, compared to the planar structure, In order for the structure 4 to approach the substrate 2 side, it is necessary to apply a large force to the central portion of the structure 4. In the manufacturing process of the MEMS element 1, since the sticking failure occurs due to the surface tension of the liquid remaining between the structure 4 and the insulating film 3 when the sacrificial film is removed, the structure 4 is formed on the substrate 2 side. Sticking can be suppressed by using the structure of the present invention (for example, the structure of the MEMS element 1 in FIG. 1) that requires a relatively large force to bring the distance closer.

  Next, the manufacturing method of the MEMS element according to the first embodiment will be described in the order of steps using the cross-sectional views of the main part of the MEMS element shown in FIGS.

  First, as shown in FIG. 5, an insulating film 3 is deposited on the main surface of the substrate 2, and a sacrificial film 7 is deposited on the insulating film 3. As the sacrificial film 7, for example, a silicon oxide film deposited by a CVD (Chemical Vapor Deposition) method is used. Subsequently, as shown in FIG. 6, a resist pattern 8 for processing the sacrificial film 7 is formed on the sacrificial film 7 by photolithography.

  Next, as shown in FIG. 7, the resist pattern 8 is subjected to heat treatment so that the surface of the resist pattern 8 is smoothed into an upwardly convex bow shape. At this time, the resist pattern 8 is not completely melted, and heat treatment is performed using a temperature and time that can cause reflow by redistribution of surface energy while maintaining an appropriate viscosity. The temperature and time of this heat treatment depend on the type and size of the resist turn 8. For example, the surface of the resist pattern 8 can be gently deformed by a heat treatment temperature of about 150 ° C. and a heat treatment time of about 2 minutes.

  Next, as shown in FIG. 8, the sacrificial film 7 that determines the surface shape of the structure 4 is etched using the resist pattern 8 having an upwardly convex bow shape as a mask. It should be noted that, in the etching, by selecting an etching selection ratio between the resist pattern 8 serving as a mask and the sacrificial film 7 as the material to be etched, the surface shape of the underlying sacrificial film 7 can be reduced to a gentle surface shape of the resist pattern 8. You can decide whether to transfer to shape. For example, if the ratio of the thickness of the resist pattern 8 to the thickness of the underlying sacrificial film 7 is 1: 1, the etching selectivity in the direction perpendicular to the main surface of the substrate 2 is set to 1: 1, whereby the resist The gentle surface shape of the pattern 8 can be transferred to the sacrificial film 7 as it is. By employing such an etching method, a sacrificial film pattern 7a having a gentle surface shape can be obtained.

  Next, as shown in FIG. 9, after removing the resist pattern 8, a conductor film to be the structure 4 is formed, and a resist pattern for processing the conductor film is formed by photolithography. Subsequently, the conductive film is etched using this resist pattern as a mask to form the structure 4. In the first embodiment, a polycrystalline silicon film having a thickness of about 500 nm deposited by, for example, a CVD method is used as the conductor film.

  Next, as shown in FIG. 10, the sacrificial film pattern 7a is removed by wet etching, washed with water, and then dried. Thereby, the non-planar convex structure 4 that is gentle with respect to the main surface of the substrate 2 can be obtained. As described above, such a convex structure 4 that is non-planar with respect to the main surface of the substrate 2 is different from the structure 4 that is flat with respect to the main surface of the substrate 2. The acting force required to draw the central portion of the substrate toward the substrate 2 is increased. Therefore, even if a liquid having a surface tension enters between the structure 4 and the insulating film 3 during washing, sticking between the structure 4 and the insulating film 3 can be suppressed. Thereafter, the electrode 6 is formed on the substantially central portion of the structure 4 via the insulating film 5, whereby the MEMS element 1 according to the first embodiment shown in FIG. 1 is substantially completed.

  In the first embodiment, as a method of manufacturing the convex structure 4 that is non-planar with respect to the main surface of the substrate 2, reflow by heat treatment of the resist pattern 8 is used, but a desired shape is obtained. The manufacturing process for this is not limited to the method described above. For example, the sacrificial film 7 is processed in multiple stages using a photolithography method, and the shoulder portion of the sacrificial film 7 is tapered, or a gray scale mask is used instead of the glass mask used in the photolithography method. Can be applied.

  Thus, according to the first embodiment, the structure 4 is drawn toward the substrate 2 by making the shape of the structure 4 a non-planar convex shape with respect to the main surface of the substrate 2. Since a relatively large force is required, the occurrence of defects due to sticking in the manufacturing process of the MEMS element 1 can be suppressed, and the manufacturing yield of the MEMS element 1 is improved. Moreover, since it can manufacture by the existing semiconductor process technique, without using a special solvent and a solvent, the MEMS element 1 can be manufactured cheaply. Further, since the hinge portion of the structure 4 becomes gentle, stress concentration at a specific location or electric field concentration at a specific location can be avoided, and mechanical failure or electrical failure due to aging of the structure 4 is prevented. Can be controlled.

(Embodiment 2)
A manufacturing method of a semiconductor device using the MEMS element according to the second embodiment of the present invention as a coupling switch between LSI wirings will be described in the order of steps with reference to cross-sectional views of the main part of the semiconductor device shown in FIGS. Note that a CMOS (Complementary Metal Oxide Semiconductor) device is illustrated as an LSI device. In the following description, a p-channel field effect transistor is abbreviated as pMIS, and an n-channel field effect transistor is abbreviated as nMIS. In the second embodiment, a coupling switch between LSI wirings is simply referred to as a coupling switch.

  First, as shown in FIG. 11, a semiconductor substrate (a semiconductor wafer processed into a circular thin plate, hereinafter referred to as a substrate) 9 made of, for example, p-type silicon single crystal is prepared. Next, after forming an isolation portion 10 made of an insulating film in the element isolation region, impurities are ion-implanted into the substrate 9 to form a p-well 11 and an n-well 12. Impurities (eg, boron) having p-type conductivity are ion-implanted into the p-well 11, and impurities (eg, phosphorus or arsenic) having n-type conductivity are ion-implanted into the n-well 12.

  Next, the gate insulating film 13, the gate electrode 14, and the cap insulating film 15 constituting the nMIS and pMIS are formed, and the side wall 16 is formed on the side wall of the gate electrode 14. Subsequently, an impurity (for example, phosphorus or arsenic) having n-type conductivity is ion-implanted into the p-well 11 on both sides of the gate electrode 14, and the n-type semiconductor region 17 functioning as the source / drain of the nMIS is formed in the gate electrode 14 and It is formed in a self-aligned manner with respect to the sidewall 16. Similarly, an impurity exhibiting p-type conductivity (for example, boron fluoride) is ion-implanted into the n-well 12 on both sides of the gate electrode 14, and the p-type semiconductor region 18 functioning as the source / drain of the pMIS is formed into the gate electrode 14 and It is formed in a self-aligned manner with respect to the sidewall 16.

  Next, after the interlayer insulating film 19a and the cap insulating film 19b are formed on the substrate 9, the cap insulating film 19b and the interlayer insulating film 19a are sequentially processed by etching using the resist pattern as a mask to form the connection holes 20. The connection hole 20 is formed in a necessary portion such as on the n-type semiconductor region 17 or the p-type semiconductor region 18. Subsequently, a plug 21 having, for example, tungsten as a main conductor is formed inside the connection hole 20.

  Next, as shown in FIG. 12, a sacrificial film 7 is deposited on the substrate 9, and a resist pattern 8 for processing the sacrificial film 7 is formed by photolithography. The resist pattern 8 is formed only in a region corresponding to the gap of the coupling switch.

  Next, as shown in FIG. 13, the resist pattern 8 is subjected to heat treatment so that the resist pattern 8 has an upwardly convex bow shape. The heat treatment conditions are determined in consideration of the viscosity of the resist to be used or the volume of the resist pattern 8. In the second embodiment, as the dimensions of the coupling switch, the length is several μm, the width is about the size of the switch contact portion, and the thickness is about the thickness of the LSI wiring. The resist material used in (1) is used. Therefore, a temperature of about 150 ° C. and a time of about 2 minutes were adopted as the heat treatment conditions for the resist pattern 8. When the size of the coupling switch or the allowable power amount of the switch contact is different from that of the second embodiment, the dimension and gap of the coupling switch will change, so the heat treatment conditions for the resist pattern 8 must be changed as appropriate.

Next, as shown in FIG. 14, the sacrificial film 7 is processed by anisotropic dry etching using the resist pattern 8 as a mask. When the shape of the resist pattern 8 is transferred to the sacrificial film 7 using the anisotropic dry etching method, if the thickness of the resist pattern 8 is the same as the thickness of the sacrificial film that is a material to be processed, the resist pattern 8 and the sacrificial film are sacrificed. If the etching selectivity of the film 7 is set to 1: 1, in principle, the processed shape of the resist pattern 8 can be transferred to the underlying sacrificial film 7 as it is. If the thickness of the resist pattern 8 is a (nm) and the thickness of the sacrificial film 7 is b (nm), if the etching selection ratio between the resist pattern 8 and the sacrificial film 7 is set to a: b, in principle The processed shape of the resist pattern 8 can be transferred to the underlying sacrificial film 7 as it is. In the second embodiment, a silicon oxide-based insulating film is assumed for the sacrificial film 7. In a dry etching method using a C ₄ F ₈ gas system, the etching selectivity between a resist material generally used in semiconductor process technology and a silicon oxide film-based insulating film can be easily controlled. In the second embodiment, the selection ratio between the resist pattern 8 and the sacrificial film 7 is adjusted by adding O ₂ gas to C ₄ F ₈ gas. Thereby, the resist pattern 8 having an upwardly convex bow shape can be transferred to the sacrificial film 7.

  Next, as shown in FIG. 15, after depositing a metal film on the substrate 9, the coupling switch structure 4 is formed by etching using the resist pattern as a mask. This metal film is the main material of the coupling switch, and at the same time, constitutes the wiring 4L connected to the plug 21 and the like formed on the substrate 9. The structure 4 and the wiring 4L are made of a conductor film whose main conductor is aluminum, for example.

  Next, as shown in FIG. 16, a sacrificial film 22 is deposited on the substrate 9 and the surface thereof is planarized. Then, the sacrificial film 22 is etched using the resist pattern 23 as a mask, and the coupling switch structure 4 operates. A space 24 for defining the space to be formed is formed.

  Next, as shown in FIG. 17, after removing the resist pattern 23, a first cap film 25 is deposited on the substrate 9 including the inside of the space 24. Examples of the first cap film 25 include a silicon nitride film. Subsequently, the first cap film 25 is etched using the resist pattern 26 as a mask, and a hole 27 serving as a contact portion for connecting the coupling switch structure 4 and the upper wiring is formed in a part of the first cap film 25. Form. When the hole 27 is formed, the etching conditions are set so that the etching stops at the sacrificial film 22.

  Next, as shown in FIG. 18, after removing the resist pattern 23, a second cap film 28 is deposited on the substrate 9 including the inside of the hole 27 to connect the coupling switch structure 4 and the upper layer wiring. A contact 29 for connection is formed. The second cap film 28 can be exemplified by a metal film whose main conductor is aluminum, for example.

  Next, as shown in FIG. 19, a resist pattern 30 is formed on the substrate 9. The resist pattern 30 is formed to form a hole for removing the sacrificial film pattern 7 a and the sacrificial film 22 in a part of the first cap film 25 and the second cap film 28.

  Next, as shown in FIG. 20, a hole 31 is formed in a part of the first cap film 25 and the second cap film 28 by etching using the resist pattern 30 as a mask. Subsequently, as shown in FIG. 21, the sacrificial film pattern 7a and the sacrificial film 22 are removed through the holes 31 by wet etching or isotropic dry etching, and gaps 32a and 32b in which the structure 4 operates are formed. Form. During the pure cleaning process or the rinsing process performed on the substrate 9 after the sacrificial film pattern 7a and the sacrificial film 22 are removed, liquid enters between the structure 4 and the underlying cap insulating film 19b. However, since the shape of the coupling switch structure 4 is a non-planar convex shape with respect to the underlying cap insulating film 19b, the force repelling the surface tension of the liquid that has entered between the surrounding objects is flat. Therefore, the coupling switch of the second embodiment can suppress sticking in the manufacturing process more than the coupling switch having the planar shape structure.

  Next, as shown in FIG. 22, the third cap film 33 is deposited on the substrate 9 including the inside of the hole 31 to close the hole 31 formed in the first cap film 25 and the second cap film 28. The third cap film 33 can be exemplified by a metal film whose main conductor is aluminum, for example. By using the second cap film 28 and the third cap film 33 as metal films, it can also serve as a plug connected to the upper wiring.

  Next, as shown in FIG. 23, the third cap film 33 and the second cap film 28 are sequentially processed by etching using the resist pattern as a mask, and then an interlayer insulating film 34 is deposited on the substrate 9, and further the resist A connection hole 36 is formed in the interlayer insulating film 34 by etching using the pattern 35 as a mask.

  Next, as shown in FIG. 24, the resist pattern 35 is removed, and a metal film having, for example, aluminum as a main conductor is deposited on the substrate 9 including the inside of the connection hole 36. Then, etching using the resist pattern as a mask is performed. Thus, the metal film is processed to form the wiring 37. Through the above steps, the semiconductor device including the coupling switch according to the second embodiment is substantially completed. Thereafter, an upper layer wiring can be further formed.

  In the second embodiment, in the process of manufacturing the coupling switch, the step of closing the hole 27 with the third cap film 33 depends on the deposition method of the third cap film 33, but the third cap film 33 is a coupling switch. When it is placed in a room temperature environment, it is blocked with a pressure that is negative. Since the coupling switch is a mechanism in which the structure 4 is displaced in a direction perpendicular to the main surface of the substrate 9 due to thermal expansion due to Joule heat when current flows through the structure 4, the gaps 32a and 32b having a narrow negative pressure are formed. The Joule heat can be efficiently returned to the operation of the structure 4 while functioning as a heat reservoir and suppressing the diffusion of heat to surrounding materials.

  In the second embodiment, the material of the structural body 4 that causes the displacement is configured by a single film. However, in the case of the purpose of obtaining a larger amount of displacement or the complexity of the manufacturing process is allowed, it is efficient. For the purpose of obtaining the displacement amount, a structure of a bimorph mechanism using a difference in thermal expansion coefficients of a plurality of films may be used. At this time, the step of forming the non-planar convex structure 4 with respect to the substrate 9 may be applied to a layer near the substrate 9, but the sacrificial film is formed by the internal stress of the film deposited on the upper layer. It is not desirable that the shape of the structure after removal is different from the target shape. For this reason, attention must be paid to the shape of the structure in a stationary state, and conditions for depositing a plurality of films must be determined.

  As described above, according to the second embodiment, since the occurrence of sticking can be suppressed in the MEMS element used as a coupling switch for LSI wiring, the yield of a semiconductor device in which the MEMS element is mounted as a coupling switch between LSI wirings is improved. To do.

(Embodiment 3)
A method of operating the coupling switch between LSI wirings according to the third embodiment of the present invention will be described with reference to FIGS.

  FIG. 25 is a cross-sectional view of a principal part of a semiconductor device using a MEMS element as a coupling switch between LSI wirings.

  The coupling switch has a structure in which the structure 4 and a wiring 41 through which a signal is transmitted are separated by an insulating film 42. The wiring 41 is made of, for example, a polycrystalline silicon film, and the insulating film 42 is made of, for example, a silicon nitride film. The method for removing the sacrificial film or the method for manufacturing the structure 4 is in accordance with the second embodiment described above. The coupling switch is a mechanical mechanism in which the structure 4 is selectively displaced only in a direction perpendicular to the surface of the substrate 9 due to thermal expansion due to Joule heat when a current flows inside the structure 4. Due to the deformation of the structural body 4, the second cap film 28 and the wiring 41 are electrically connected via the contact 29.

  FIG. 26 shows a schematic diagram of the connection in which the upper layer wiring and the lower layer wiring are connected using the coupling switch shown in FIG. The areas surrounded by dotted lines correspond to the coupling switches SWa, SWb, SWc, respectively. Further, the lower layer wiring L1 is the wiring 41 on the side close to the substrate 9 in FIG. 25, and the upper layer wirings L2a, L2b, L2c are formed above the lower layer wiring L1 in the second cap film in FIG. 28, the third cap film 33 and the wiring 37. Here, consider a case where a signal is transmitted from the lower layer wiring L1 to the upper layer wirings L2a, L2b, and L2c.

  When a signal is selectively transmitted from the lower layer wiring L1 to the upper layer wiring L2a, first, a GND signal is given to the lower layer wiring L1 to give a potential difference before and after the movable portion of the structure 4a. As a result, a current corresponding to the resistance of the main body of the structure 4a flows to the structure 4a, Joule heat is generated, the structure 4a itself is warmed, and the coupling switch SWa operates due to the thermal expansion effect of the material, so that the structure 4a In contact with the contact 29 in FIG. 25, the coupling switch SWa is turned on. Thus, the signal Vdd of the lower layer wiring L1 is transmitted only to the upper layer wiring L2a via the contact 29.

  Similarly, when a signal is selectively transmitted from the lower layer wiring L1 to the upper layer wiring L2b, first, a GND signal is given to the lower layer wiring L1 to give a potential difference before and after the movable portion of the structure 4b. Thereby, a current corresponding to the resistance of the main body of the structure 4b flows to the structure 4b, Joule heat is generated, the structure 4b itself is warmed, and the coupling switch SWb is operated by the thermal expansion effect of the material, so that the structure 4b The coupling switch SWb is turned on in contact with the contact 29. Thus, the signal Vdd of the lower layer wiring L1 is transmitted to the upper layer wiring L2b only via the contact 29.

  Similarly, when signals are simultaneously transmitted from the lower layer wiring L1 to the upper layer wirings L2a and L2c, a GND signal is applied to the wiring L1 to provide a potential difference in parallel before and after the movable parts of the two structures 4a and 4c. As a result, a current corresponding to the resistance of each of the structures 4a and 4c flows through the structures 4a and 4c to generate Joule heat, and the structures 4a and 4c themselves are warmed. Due to the thermal expansion effect of the material, the coupling switch SWa , SWc operate, the structures 4a, 4c come into contact with the contact 29, and the coupling switches SWa, SWc are turned on. In this way, the signal Vdd of the lower layer wiring L1 is simultaneously transmitted to the upper layer wirings L2a and L2c via the contact 29.

(Embodiment 4)
A probe recording element provided with a recording terminal portion constituted by a MEMS element according to Embodiment 4 of the present invention will be described with reference to FIGS.

  The basic structure of the recording terminal portion of the probe recording element will be described below. FIG. 27A is a top view of the recording terminal portion of the probe recording element as viewed from the side in contact with the recording dots, and FIG. 27B is an essential part of the recording terminal portion along the line AA ′ in FIG. FIG.

  A desired transistor (for example, a CMOS device) 51 is formed on the semiconductor substrate 50, and an insulating film 52 is formed on the transistor. On the insulating film 52, a gap 53, which is a space in which the movable portion of the MEMS element operates, is formed by the manufacturing method described in the first embodiment, and recording of the probe recording element is performed with the gap 53 interposed therebetween. A metal film 54 that functions as a main body of the probe movable body of the terminal portion and a heater is formed. Further, on the metal film 54, an insulating film 55 and a signal line 56 made of a metal material for transmitting recording signals are sequentially formed from the lower layer. A metal contact 57 for transmitting a recording signal in contact with the recording dot is formed on the signal line 56 at the central portion where the probe movable body is displaced most greatly.

FIG. 28 is a schematic view of the entire system including the probe recording element. The system includes a control circuit that operates the probe recording element 58, a semiconductor substrate 59 manufactured in the same manufacturing process as the probe recording element 58, and an XY stage 60 manufactured in a manufacturing process different from the probe recording element 58. Is a mechanism for recording. A probe recording element 58 is mounted on the semiconductor substrate 59, and a recording medium 61 on which recording dots are patterned is mounted on the XY stage 60. In FIG. 28, 14 probe recording elements 58 are described. However, in an actual system, 10 probe recording elements 58 formed on a single substrate 59, for example, in a rectangular shape having a side of about 10 to 20 μm are provided. It is arranged ^three or so, also, the one recording medium 61, for example, 10 ⁶ or so of the recording dots are arranged.

  FIG. 29 is an enlarged schematic view of a portion where the recording terminal portion of the probe recording element is in contact with the recording dot.

  When data is recorded on a desired recording dot 62, a signal is transmitted in the following procedure. First, current is passed through the metal film 54 to generate Joule heat, and the probe movable body 54a is moved downward (in the direction of the arrow in FIG. 29) using thermal expansion, and the metal contact 57 is connected to the recording dot 62. Make contact. At this time, the operation range of the probe movable body 54a is used in a range that shows a linear displacement with respect to the acting force, and is used in a range that does not cause nonlinear latching on the substrate 50 side.

  Thereafter, the recording signal is transmitted to the recording dots 62 via the signal line 56 operating integrally with the probe movable body 54a. Here, the recording signal is a voltage, and by connecting the media mounting surface 63 of the recording dot 62 to the ground, a current path is formed from the signal line 56 to the media mounting surface 63 via the recording dot 62. The generated Joule heat causes a phase transition of the crystal material constituting the recording dot 62, and the resistance value of the recording dot 62 changes by several digits. This operation corresponds to data recording. The recording dots 62 on the media mounting surface 63 are separated by a separation film 64 having a small heat transfer coefficient so that the generated Joule heat is not transmitted to the recording dots 62 adjacent to the desired recording dots 62.

  When reproducing the data recorded in the recording dots 62, signals are transmitted in the following procedure. First, current is passed through the metal film 54 to generate Joule heat, and the probe movable body 54a is moved downward (in the direction of the arrow in FIG. 29) using thermal expansion, and the metal contact 57 is connected to the recording dots 62. Make contact. At this time, the operation range of the probe movable body 54a is used in a range that shows a linear displacement with respect to the acting force, and is used in a range that does not cause nonlinear latching on the substrate 50 side.

  Thereafter, the recording signal is transmitted to the recording dots 62 via the signal line 56 operating integrally with the probe movable body 54a. Here, the recording signal is a voltage, and by connecting the medium mounting surface 63 of the recording dot 62 to the ground, a current path is formed on the medium mounting surface 63 from the signal line 56 via the recording dot 62. At this time, the amount of current flowing into the recording dot 62 is measured, and the resistance value of the recording dot 62 is measured to reproduce data. During reproduction, the voltage value applied from the signal line 56 is smaller than the voltage value at the time of recording, and is a voltage value that does not change the crystal state of the recording dots 62.

  In the fourth embodiment, a chalcogenide phase in which Joule heat is generated in the recording dots 62 by applying a voltage to cause a phase transition of the crystal and a resistance value of the crystal changes in the explanation of the principle of recording or reproducing. Although a change material was used, it is not limited to this. As the principle of recording or reproduction of the probe recording element, any principle may be applied as long as it can be recorded or reproduced by applying a current or voltage.

  As described above, in the fourth embodiment, when a non-planar convex shape is adopted for the probe movable body 54a of the recording terminal portion of the probe recording element, a ribbon-like probe recording element is manufactured with high yield instead of a cantilever. become able to. This eliminates the need for the signal line 56 to reciprocate over the ribbon-like probe recording element, and the probe recording element can be highly integrated.

  FIG. 30 is a plan view of an essential part along the line BB ′ in FIG. 29, showing the relationship between the arrangement of the probe recording elements and the medium mounting surface. However, a part of the insulating film and the upper layer wiring of the signal line are omitted. A region surrounded by a dotted line in FIG. 30 is a medium scanning range 65 in which one probe recording element scans in a plane and performs recording or reproduction. By arranging the ribbon-like probe recording elements in a highly integrated manner, the media scanning range 65 per probe recording element can be narrowed, so that the transfer speed or recording speed can be improved by parallel processing of data.

(Embodiment 5)
The basic structure and operation of the surface capacitive ultrasonic element manufactured using the MEMS technology according to the fifth embodiment of the present invention will be described with reference to FIGS. 31 and 32. FIG.

  31 is a top view of the main part of the surface capacitive ultrasonic element, and FIG. 32 is a cross-sectional view of the main part of the surface capacitive ultrasonic element along CC ′ of FIG. The electrode and gap structure of this surface capacitive ultrasonic element have a circular or polygonal structure when viewed from the top. In the fifth embodiment, the process of making the surface of the sacrificial film into a gentle convex shape is not limited to a structure having a bridge structure, but to a structure having a fixed surface structure such as a surface capacitive ultrasonic element. Can also be applied.

  The surface capacitive ultrasonic element is formed on the insulating film 71 formed on the semiconductor substrate 70, the lower electrode 72 defining the operation of the element formed thereon, and the gap 73 on the lower electrode 72. The film-like structure 74 that generates ultrasonic waves and the upper electrode 75 that defines the operation of the element formed on the structure 74 are also included.

  The gap 73 can be formed by the following manufacturing method, for example. First, after depositing a sacrificial film on the lower electrode 72, the surface of the sacrificial film is processed into a gently convex arch by etching using a resist pattern subjected to heat treatment or equivalent means as a mask. Subsequently, after forming a film-like structure 74 that generates ultrasonic waves on the upper layer of the sacrificial film, the sacrificial film is removed by a wet etching method or an isotropic dry etching method through the hole 76 shown in FIG. A gap 73, which is a space in which the movable part of the capacitive ultrasonic element operates, is formed. A plurality of holes 76 for etching the sacrificial film are provided for each surface capacitance type ultrasonic element, and an etching solvent or the like can easily enter even in the narrow gap 73.

  In order to operate the surface capacitive ultrasonic element, a high-frequency voltage is applied between the upper electrode 75 and the lower electrode 72, the film-like structure 74 is vibrated and operated in a range where linear deformation occurs, Ultrasonic waves are generated with the direction perpendicular to the surface of the semiconductor substrate 70 as the traveling direction. When a frequency close to the natural frequency due to the structure of the surface capacitive ultrasonic element is selected as the frequency of the voltage applied between the upper electrode 75 and the lower electrode 72 at this time, and the resonance phenomenon of the structure is used, the input voltage In contrast, the intensity of ultrasonic waves can be generated efficiently. Further, the value of the voltage applied between the upper electrode 75 and the lower electrode 72 depends on the electrode area allowed to be arranged in one surface capacitive ultrasonic element and the distance between the electrodes corresponding to the gap 73. However, when the surface capacitive ultrasonic element has a film-like surface structure with a diameter of about 50 μm, for example, a voltage in the range of about 50 to 150 V is applied between the peaks.

  In the surface capacitive ultrasonic element, the size of the upper electrode 75 and the lower electrode 72 that define the operation of the surface capacitive ultrasonic element cannot be increased due to a request for an ultrasonic frequency to be generated, which corresponds to the distance between the electrodes. By narrowing the gap 73, a surface capacitive ultrasonic element that can be driven at a low voltage can be obtained. Specifically, in order to operate at a voltage of 100 V or less, the distance of the gap 73 is about 100 nm while the diameter of the film-like surface structure is about 50 μm. In this element structure, the aspect ratio (height / height) Width) is 1/500. However, by using the MEMS technology of the first embodiment described above, a MEMS structure with a narrow gap 73 can be manufactured with a high yield, and further, an effect of suppressing sticking can be obtained without increasing the number of manufacturing steps. it can.

  Since the surface of the sacrificial film has a gentle convex shape, the structure 74 does not fall below the surface connecting both ends during the operation of the surface capacitive ultrasonic element. For this reason, the distance between the upper electrode 75 and the lower electrode 72 is increased, and the operating voltage is increased. However, the operating voltage shift is about 1% when the distance between the upper electrode 75 and the lower electrode 72 is shifted by 1%, which is effective in improving the manufacturing yield of the surface capacitive ultrasonic element. Is considered higher.

Further, as an advantage of the surface capacitive ultrasonic element manufactured by using the MEMS technology, for example, when used as an input device of a non-contact diagnostic apparatus, an ultrasonic wave is formed by arraying the surface capacitive ultrasonic elements. The tomographic image can be easily two-dimensionalized without performing a planar mechanical scanning operation. Assuming that one surface capacitive ultrasonic element corresponds to one input scanning line, it is possible to obtain information sufficient as an image diagnostic apparatus by arraying several hundred surface capacitive ultrasonic elements. it can. In addition, the surface capacitive ultrasonic elements corresponding to one scanning line itself are also arrayed, for example, manufactured as a matrix array of 36 rows and 36 columns, so that the reliability of the diagnostic imaging apparatus is further increased and the input signal is highly reliable. Can be obtained in degrees. In either method, since it is necessary to arrange about 10 ³ to 10 ⁵ surface capacitive ultrasonic elements, it is desired to improve the manufacturing yield of the surface capacitive ultrasonic elements. By using the manufacturing process based on the MEMS technology, the manufacturing yield of the surface capacitive ultrasonic element can be improved.

  In addition, the surface capacitive ultrasonic element manufactured by using the MEMS technology undergoes fatigue failure in the process of actual use. Possible causes of the breakdown include a breakdown of the film due to mechanical stress concentration on the support portion of the film-like structure or an electrical breakdown of the film due to electric field concentration on the support portion of the film-like structure. However, if the manufacturing process based on the MEMS technology of the first embodiment described above is used, a portion where the stress of the structure is concentrated can be formed in a non-planar convex shape with respect to the substrate. Therefore, it is possible to obtain a highly reliable surface capacitive ultrasonic element.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention can be widely used for semiconductor devices including devices manufactured by MEMS technology.

1 is a cross-sectional view of a main part of a MEMS element according to a first embodiment. (A) is the schematic diagram which looked at the beam which both ends of the initial state were fixed from the side, (b) is the schematic diagram which looked at the displacement direction by buckling of the beam where both ends were fixed from the side. (A) is a schematic view of the displacement direction due to the acting force of the beam fixed at both ends as viewed from the side, and (b) is the load applied in the direction perpendicular to the central point of the beam in FIG. It is a graph which shows the result of having calculated | required the relationship with a deformation | transformation amount by calculation. It is the schematic diagram which looked at the displacement direction by the thermal expansion of the beam by which both ends were fixed from the side. 5 is a fragmentary cross-sectional view of the MEMS element according to Embodiment 1 during a manufacturing step thereof; FIG. FIG. 6 is a fragmentary cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 5; FIG. 7 is an essential part cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 6; FIG. 8 is a fragmentary cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 7; FIG. 9 is a fragmentary cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 8; FIG. 10 is a main-portion cross-sectional view of the MEMS element during the manufacturing process following FIG. 9; FIG. 10 is a fragmentary cross-sectional view of a semiconductor device during a manufacturing step in which the MEMS element according to the second embodiment is used as a coupling switch between LSI wires; FIG. 12 is an essential part cross-sectional view of the MEMS element during a manufacturing step following that of FIG. 11; 13 is a fragmentary cross-sectional view of the MEMS element during a manufacturing step following that of FIG. 12; FIG. FIG. 14 is an essential part cross-sectional view of the MEMS element during a manufacturing step following that of FIG. 13; FIG. 15 is a main-portion cross-sectional view of the MEMS element during the manufacturing process following FIG. 14; FIG. 16 is a main-portion cross-sectional view of the MEMS element during the manufacturing process following FIG. 15; FIG. 17 is an essential part cross-sectional view of the MEMS element during a manufacturing step following that of FIG. 16; FIG. 18 is an essential part cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 17; FIG. 19 is an essential part cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 18; FIG. 20 is an essential part cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 19; FIG. 21 is an essential part cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 20; FIG. 22 is an essential part cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 21; FIG. 23 is a fragmentary cross-sectional view of the MEMS device during a manufacturing step following that of FIG. 22; FIG. 24 is an essential part cross-sectional view of the MEMS element during a manufacturing step following that of FIG. 23; FIG. 6 is a cross-sectional view of a main part of a semiconductor device using a MEMS element according to a third embodiment as a coupling switch between LSI wirings. FIG. 26 is a schematic diagram of a connection in which an upper layer wiring and a lower layer wiring are connected using the coupling switch illustrated in FIG. 25. (A) is the top view which looked at the recording terminal part of the probe recording element by Embodiment 4 from the side which contact | connects a recording dot, (b) is principal part sectional drawing along the AA 'line of the same figure (a). It is. FIG. 6 is a schematic diagram of the entire system including a probe recording element according to a fourth embodiment. FIG. 10 is an enlarged schematic diagram of a portion where a recording terminal portion of a probe recording element according to Embodiment 4 and a recording dot are in contact with each other. It is a principal part top view along the BB 'line | wire of FIG. FIG. 10 is a top view of a main part of a surface capacitive ultrasonic element according to a fifth embodiment. FIG. 32 is a main-portion cross-sectional view of the surface capacitive ultrasonic element along CC ′ in FIG. 31.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 MEMS element 2 Semiconductor substrate 3 Insulating film 4 Structure 4a, 4b, 4c Structure 4L Wiring 5 Insulating film 6 Electrode 7 Sacrificial film 7a Sacrificial film pattern 8 Resist pattern 9 Semiconductor substrate 10 Separation part 11 P well 12 N well 13 Gate Insulating film 14 Gate electrode 15 Cap insulating film 16 Side wall 17 n-type semiconductor region 18 p-type semiconductor region 19a Interlayer insulating film 19b Cap insulating film 20 Connection hole 21 Plug 22 Sacrificial film 23 Resist pattern 24 Space 25 First cap film 26 Resist Pattern 27 Hole 28 Second cap film 29 Contact point 30 Resist pattern 31 Holes 32a and 32b Gap 33 Third cap film 34 Interlayer insulating film 35 Resist pattern 36 Connection hole 37 Wiring 41 Wiring 42 Insulating film 50 Semiconductor substrate 51 Transistor 52 Insulating film 53 Gi Cap 54 Metal film 54 a Probe movable body 55 Insulating film 56 Signal line 57 Metal contact 58 Probe recording element 59 Semiconductor substrate 60 XY stage 61 Recording medium 62 Recording dot 63 Media mounting surface 64 Separating film 65 Media scanning range 70 Semiconductor substrate 71 Insulating film 72 Lower electrode 73 Gap 74 Structure 75 Upper electrode 76 Hole A1 Rod shape A2, A3 Convex shape B1 Rod shape B2, B3 Convex shape C1, C2 Convex shape L1 Lower layer wirings L2a, L2b, L2c Upper layer wirings SWa, SWb, SWc coupling switch

Claims (19)

A first insulating film formed on the main surface of the semiconductor substrate;
A deformable structure partly fixed on the first insulating film and having a non-planar convex shape with respect to the main surface of the semiconductor substrate when in a stationary state;
A semiconductor device comprising an element including a first electrode formed on a part of the structure through a second insulating film.   2. The semiconductor device according to claim 1, wherein the structure is configured to be movable in a direction perpendicular to a main surface of the semiconductor substrate.   2. The semiconductor device according to claim 1, wherein the element functions as a coupling switch between wirings that electrically connect the upper layer wiring and the lower layer wiring.   2. The semiconductor device according to claim 1, wherein a signal line that operates integrally with the structure is formed between the second insulating film and the first electrode.   5. The semiconductor device according to claim 4, wherein the structure is configured to be movable in a direction perpendicular to a main surface of the semiconductor substrate.   6. The semiconductor device according to claim 4, wherein the structure is a main body of a probe movable body of a recording terminal portion of a probe recording element, and the first electrode is in contact with a recording dot formed on a recording medium to transmit a recording signal. And a recording signal is transmitted to the recording dots via the signal line.   7. The semiconductor device according to claim 6, wherein the recording dots are made of a chalcogenide phase change material. A first insulating film formed on the main surface of the semiconductor substrate;
A second electrode formed in a central portion on the first insulating film;
A deformable structure in which a peripheral portion is fixed on the first insulating film and becomes a non-planar convex shape with respect to the main surface of the semiconductor substrate when stationary.
A semiconductor device comprising an element including a first electrode formed on a part of the structure.   9. The semiconductor device according to claim 8, wherein the structure does not have a non-planar concave shape with respect to a main surface of the semiconductor substrate during operation of the element.   9. The semiconductor device according to claim 8, wherein the element functions as a sensor when the structure vibrates.   9. The semiconductor device according to claim 8, wherein the element is a surface capacitive ultrasonic element that generates ultrasonic waves by applying a high-frequency voltage between the first electrode and the second electrode to vibrate the structure. There is a semiconductor device. A method of manufacturing a semiconductor device comprising the following steps:
(A) a step of sequentially forming a first insulating film and a first sacrificial film on a semiconductor substrate;
(B) forming a resist pattern on the first sacrificial film;
(C) a step of processing the surface of the resist pattern into a convex bow shape;
(D) After the step (c), the step of etching the first sacrificial film using the resist pattern as a mask to form a first sacrificial film pattern having a convex bow shape on the surface,
(E) a step of removing the resist pattern after the step (d);
(F) After the step (e), forming a conductor film on the first sacrificial film pattern and patterning the conductor film to form a structure;
(G) After the step (f), removing the first sacrificial film pattern;
(H) After the step (g), forming a first electrode on a part of the structure via a second insulating film.   13. The method of manufacturing a semiconductor device according to claim 12, wherein in the step (c), the resist pattern is subjected to heat treatment.   13. The method of manufacturing a semiconductor device according to claim 12, wherein the conductor film is a polycrystalline silicon film. 13. The method of manufacturing a semiconductor device according to claim 12, wherein the step (h) further includes the following steps:
(H1) forming a signal line made of a conductor film on the second insulating film;
(H2) A step of forming the first electrode at a central portion on the signal line. A method for manufacturing a semiconductor device, including manufacturing an element that functions as a coupling switch between wirings that electrically connect upper-layer wiring and lower-layer wiring, which includes the following steps;
(A) sequentially forming a first insulating film and a first sacrificial film on the main surface of the semiconductor substrate;
(B) forming a resist pattern on the first sacrificial film;
(C) a step of processing the surface of the resist pattern into a convex bow shape;
(D) After the step (c), the step of etching the first sacrificial film using the resist pattern as a mask to form a first sacrificial film pattern having a convex bow shape on the surface,
(E) a step of removing the resist pattern after the step (d);
(F) After the step (e), forming a conductor film on the first sacrificial film pattern and patterning the conductor film to form a structure;
(G) after the step (f), forming a second sacrificial film covering the structure;
(H) after the step (g), forming a third insulating film surrounding the structure and defining a region of the structure;
(I) forming a hole in a part of the third insulating film located on the central part of the structure, and forming a contact part made of a conductor film inside the hole;
(J) after the step (i), removing the first and second sacrificial films;
(K) The process of forming the 1st wiring electrically connected to the said contact part after the said process (j).   17. The method of manufacturing a semiconductor device according to claim 16, wherein the structure is a part of the lower layer wiring, and the first wiring is a part of the upper layer wiring. 17. The method of manufacturing a semiconductor device according to claim 16, wherein the step (f) further includes the following steps;
(F1) forming a second insulating film on the structure;
(F2) forming a second wiring on a part of the second insulating film.   19. The method of manufacturing a semiconductor device according to claim 18, wherein the second wiring is a part of the lower layer wiring, and the first wiring is a part of the upper layer wiring.