JP4505671B2 - Signal extraction structure for semiconductor microelectromechanical devices - Google Patents

Description

  The present invention relates to a signal extraction structure of a semiconductor microelectromechanical device that extracts an electrical signal from a semiconductor microelectromechanical device formed by joining a semiconductor plate and an insulating substrate.

  2. Description of the Related Art Conventionally, a semiconductor microelectromechanical device having a structure in which a semiconductor plate and an insulating substrate are bonded and used for detecting pressure, acceleration, and the like has been used. Structures such as weights and thin film portions are formed on the semiconductor plate of this semiconductor microelectromechanical device by etching or the like. When an external force such as pressure or acceleration is applied to the semiconductor microelectromechanical device, the structure is displaced. The electric signal changes due to the deformation. This electrical signal is extracted to the outside, and an external circuit or the like detects the external force based on this signal.

  As such a semiconductor microelectromechanical device, for example, as described in Patent Document 1, a weight portion serving as a movable electrode is formed on a semiconductor plate, and a fixed electrode is arranged on a glass plate joined to the semiconductor plate. Acceleration sensors are known. When acceleration is applied to the acceleration sensor, the distance between the weight portion and the fixed electrode changes, and the capacitance between the weight portion and the fixed electrode changes. This acceleration sensor uses the capacitance as an electric signal, and the electric signal is taken out from the fixed electrode through a through hole provided in the glass plate. This through-hole portion is a path through which an electric signal is taken out by providing a through-hole in a glass plate and providing a conductive film continuous with a fixed electrode on the inner surface. In this acceleration sensor, a conductive reinforcing portion is formed in the vicinity of the through hole before or after the conductive film is formed in order to prevent disconnection of the connection path or contact failure due to insufficient thickness of the conductive film. Further, the through hole portion is filled with a filler, and the portion provided with the weight portion and the fixed electrode is sealed in an airtight state.

Further, as described in Patent Document 2, as a structure for taking out an electrical signal from a semiconductor microelectromechanical device different from the above, the semiconductor plate and the glass plate are joined and then provided on the glass plate. A structure in which the through-hole is filled with a conductive paste is known. Using this conductive paste as a path for taking out an electric signal to the outside, the electric signal is taken out from the electrode of the semiconductor plate.
Japanese Patent Application Laid-Open No. 7-113817 JP-A-10-213441

  However, in the signal extraction structure of the semiconductor microelectromechanical device as described above, the manufacturing process becomes complicated because it is filled with a filler, a conductive paste, or the like, or a reinforcing portion is formed. There is a problem that the manufacturing cost of the device becomes high. Further, in the structure in which the through holes of the glass plate are filled with the conductive paste as in the technique described in Patent Document 2, voids are likely to be generated inside the conductive paste, and the reliability as the conductive path is lacking. There's a problem. Since the conductive paste is a large lump with a different material from the glass plate or semiconductor plate, a large thermal stress is generated when the temperature changes, and the glass plate or semiconductor plate is affected. There is a problem that an electric signal generated by an external force is not appropriate.

  In addition, when forming a through-hole on a glass plate by blasting, chipping or the like occurs and an abnormal surface is generated in the shape of the inner surface to be bonded to the semiconductor plate. There was a problem that the reliability of the conductive path could not be obtained.

  The present invention has been made in view of the above problems, and is a conductive low-melting-point material that melts when an insulating substrate and a semiconductor plate are anodically bonded to a part of an electrical signal extraction path to the outside. It is an object of the present invention to provide a signal extraction structure for a semiconductor microelectromechanical device that can appropriately generate and reliably extract an electric signal and reduce manufacturing costs. .

  In order to achieve the above object, an invention according to claim 1 includes an insulating substrate provided with a through hole, a semiconductor plate formed with a movable structure and anodically bonded to one surface of the insulating substrate, and the semiconductor plate insulated from the semiconductor plate. The through-hole bonded to the fixed electrode provided on the bonding surface with the substrate and generating an electric signal in accordance with the movement of the structure, and the fixed electrode and / or a semiconductor plate serving as a pair of the fixed electrode A conductive pad provided in the vicinity; an insulating film provided between the conductive pad joined to the fixed electrode and the semiconductor plate; and the conductive pad or semiconductor plate formed in the vicinity of the through hole and in the inner surface of the through hole; A signal extraction structure of a semiconductor microelectromechanical device having a conductive extraction film for connecting and connecting to the outside to extract an electric signal, and in the vicinity of a through hole of a surface to be bonded to the semiconductor plate of the insulating substrate, Guidance A conductive low-melting-point material film is provided in advance so as to partially overlap the drawer film, and when the insulating substrate and the semiconductor plate are anodically bonded, the low-melting-point material film is heated by the heat during anodic bonding. It is configured to be melted and connected in close contact with the conductive pad or the semiconductor plate.

  According to a second aspect of the present invention, in the first aspect of the present invention, the through hole has a reverse taper portion that spreads toward the bonding surface between the insulating substrate and the semiconductor plate.

  According to a third aspect of the present invention, in the first aspect of the present invention, the fixed electrode and the low melting point material film are made of the same material.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the conductive pad is made of a conductive low melting point material that melts by the heat of anodic bonding when the insulating substrate and the semiconductor plate are anodic bonded. .

  According to a fifth aspect of the invention, in the first aspect of the invention, the conductive extraction film is formed after the insulating substrate and the semiconductor plate are joined.

  According to a sixth aspect of the present invention, in the first aspect of the invention, the conductive pad is a donut shape in which a hole that is coaxial with the through hole is provided in advance when the insulating substrate and the semiconductor plate are joined. Is.

  The invention of claim 7 is the invention of claim 1, wherein the low melting point material film is made of an Au-Sn alloy.

  The invention of claim 8 is the invention of claim 7, further comprising a base made of a conductive material for forming a low melting point material film on the insulating substrate, and the base is configured to be shared with the fixed electrode. Is.

  According to a ninth aspect of the present invention, in the first aspect of the invention, the electrical signal is taken out by wire bonding directly to the conductive pad.

  According to a tenth aspect of the present invention, in the first aspect of the invention, a molten ball made of a conductive low melting point material is disposed in advance on the side of the through hole to be joined to the semiconductor plate, and the insulating substrate and the semiconductor plate are anodes. When bonded, the molten ball is melted by the heat of anodic bonding, and the periphery of the welded portion between the conductive pad and the low melting point material film is sealed.

  According to an eleventh aspect of the present invention, in the tenth aspect, the low melting point material film is made of an Au-Sn alloy, and the molten ball is made of an Sn alloy.

  According to a twelfth aspect of the present invention, in the seventh aspect of the invention, a brazing material ball made of a conductive low-melting-point material is disposed in advance on the opposite side of the through hole to the side to which the semiconductor plate is bonded, and the insulating substrate. And the semiconductor plate are anodically bonded, the brazing material balls are melted by the heat of the anodic bonding and welded to the conductive extraction film, and a bump portion protruding from the insulating substrate is formed. It is possible to take out an electric signal to the external substrate by directly joining to the external substrate.

  According to the first aspect of the present invention, when the insulating substrate and the semiconductor plate are anodically bonded, the low melting point material film melts and is in close contact with the conductive pad, so that the conductive pad and the conductive extraction film are reliably connected. It is possible to improve the conduction reliability of a path for connecting and extracting an electric signal. In addition, at the time of anodic bonding between the insulating substrate and the semiconductor plate, the connection between the conductive pad and the conductive extraction film and the structure portion of the fixed electrode and the semiconductor plate can be sealed and kept airtight at the same time. The manufacturing process of the electromechanical device is simplified, and the manufacturing cost can be reduced. Furthermore, since the path for taking out the electrical signal is constituted by a thin film, even if the temperature changes, almost no thermal stress is generated, and the insulating substrate and the semiconductor plate are hardly deformed. Can be generated.

  According to the invention of claim 2, since the reverse tapered portion is provided in the through hole, the low melting point material film can be stably formed from the upper part to the lower part of the reverse tapered part, and the conductive pad and the conductive extraction film are more reliably formed. It becomes possible to improve the conduction reliability.

  According to the invention of claim 3, since the fixed electrode and the low melting point material film are made of the same material, the low melting point material film can be formed at the same time when the fixed electrode is formed, and the conduction reliability is improved. In addition, the manufacturing process becomes simpler and the manufacturing cost of the semiconductor microelectromechanical device can be reduced.

  According to the invention of claim 4, since the conductive pad is also made of a low melting point material, the low melting point material film and the conductive pad are melted at the time of anodic bonding between the insulating substrate and the semiconductor plate, and the conductive pad and the low melting point material film are more It is possible to reliably connect and improve conduction reliability, and it is possible to more reliably seal the structure portion of the fixed electrode and the semiconductor plate.

  According to the invention of claim 5, since the conductive extraction film is formed after anodic bonding of the insulating substrate and the semiconductor plate, the conductive extraction film is surely overlapped with the low melting point material film connected to the conductive pad. Thus, the conductive extraction film is reliably connected to the conductive pad and the low melting point material film, and the conduction reliability can be improved.

  According to the invention of claim 6, since the conductive pad is a donut shape provided with a hole coaxial with the through hole of the insulating substrate after the anodic bonding of the insulating substrate and the semiconductor plate, the volume of the conductive pad is small. As a result, the parasitic capacitance between the semiconductor plate and the fixed electrode is lowered, and it is possible to improve the change characteristics of the semiconductor microelectromechanical device with respect to the external force. Further, by using the holes of the conductive pads, the insulating substrate and the semiconductor plate can be easily aligned and anodic bonded.

  According to the seventh aspect of the present invention, since the low melting point material film is formed of the Au—Sn alloy, the low melting point material film is easily melted at the time of anodic bonding, and the conductive pad and the conductive extraction film are bonded easily and reliably. It becomes possible to do.

  According to the invention of claim 8, since the base for forming the low-melting-point material film is shared with the fixed electrode, the step of forming the fixed electrode and the base can be performed at the same time, and the semiconductor microelectromechanical device is manufactured. The process can be simplified and the manufacturing cost can be reduced.

  According to the ninth aspect of the present invention, since the wire bonding is directly performed on the conductive pad, even if the surface roughness of the inner surface of the through hole is large and the electric resistance of the conductive extraction film is large, the signal is reliably extracted avoiding this. Therefore, it is possible to improve conduction reliability.

  According to the invention of claim 10, since the molten ball seals the periphery of the welded portion between the conductive pad and the low melting point material film, the airtightness of the structure portion of the fixed electrode and the semiconductor plate is improved while further improving the conduction reliability. The holding can be performed more reliably.

  According to the invention of claim 11, since the low melting point material film is an Au—Sn alloy and the molten ball is an Sn type alloy, the compatibility between the molten ball and the low melting point material film is good, and the molten ball is reliable. In addition, it is possible to obtain the effect of improving conduction reliability and maintaining airtightness more reliably by welding to a low melting point material film.

  According to the invention of claim 12, the bump portion is formed by the brazing material ball, the bump portion is directly connected to the external substrate, and the electric signal is taken out directly to the external substrate through the bump portion. The resistance of the path taken out from the conductive extraction film to the external substrate is reduced, and the attenuation of the electric signal can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1A, 1B, 2, and 3A, 3B show an acceleration sensor that is one of the semiconductor microelectromechanical devices according to the first embodiment of the present invention. This acceleration sensor includes a semiconductor plate 1, insulating substrates 2 and 3, conductive extraction films 4 a and 4 b, a low melting point material film 5, a fixed electrode 6, conductive pads 7 a and 7 b, and an insulating film 8. 3 is a three-layer structure in which the insulating substrates 2 and 3 are anodically bonded to the upper and lower surfaces of the semiconductor plate 1 on which a movable structure is formed. This acceleration sensor is a so-called capacitance type acceleration sensor. When acceleration is applied, the structure of the semiconductor plate 1 moves, and the capacitance between the fixed electrode 6 and the semiconductor plate 1 changes. The capacitance is taken out as an electric signal.

  The semiconductor plate 1 is formed with a weight portion 1a and a beam portion 1b that supports it as a movable structure. The beam portion 1b is provided around the weight portion 1a and has a long length and is easily bent. Spaces 1c and 1d are provided above and below the weight portion 1a, and the weight portion 1a is configured to be movable in the direction indicated by the arrow in FIG.

  The insulating substrates 2 and 3 are made of, for example, glass, and the insulating substrate 2 is provided with through holes 2a and 2b formed by blasting. Conductive lead films 4a and 4b are formed on the inner surfaces of the through holes 2a and 2b and in the vicinity thereof. The conductive extraction films 4a and 4b are provided separately so that the portion in the vicinity of the through hole 2a and the portion in the vicinity of the through hole 2b are electrically insulated.

  A conductive low melting point material film 5 is formed in the vicinity of each of the through holes 2 a and 2 b on the side to be joined to the semiconductor plate 1. The low-melting-point material films 5 provided in two places in this way are formed so as to partially overlap the conductive extraction films 4a and 4b on the inner surfaces of the through holes 2a and 2b. Each low melting point material film 5 is also joined to conductive pads 7a and 7b, which will be described later, on the lower surface of the insulating substrate 2 on the side joined to the semiconductor plate 1, respectively. The conductive pad 7b and the conductive extraction film 4b are electrically connected to each other.

  A fixed electrode 6 is formed on the lower surface of the insulating substrate 2. The fixed electrode 6 is provided so as to face the weight portion 1a according to the position of the weight portion 1a of the semiconductor plate 1. When acceleration is applied to the acceleration sensor, the fixed electrode 6 and the weight portion 1a The capacitance between the fixed electrode 6 and the semiconductor plate 1 is changed by changing the distance of the space 1c between the fixed electrode 6 and the semiconductor plate 1. The conductive extraction films 4a and 4b, the low melting point material film 5, and the fixed electrode 6 are conductive thin films, respectively, and are formed on the insulating substrate 2 before anodic bonding of the semiconductor plate 1 and the insulating substrate 2 as will be described later. Formed.

  Conductive pads 7 a and 7 b are provided on the upper surface of the semiconductor plate 1 on the side bonded to the insulating substrate 2. The conductive pad 7 a is disposed so as to be in contact with the lower surface of the insulating substrate 2 near the through hole 2 a and a part of the fixed electrode 6. An insulating film 8 such as glass is provided between the conductive pad 7a and the semiconductor plate 1, and the semiconductor plate 1 and the fixed electrode 6 are insulated so as not to be short-circuited. In addition, the conductive pad 7b is disposed so as to contact the lower surface of the insulating substrate 2 in the vicinity of the through hole 2b.

  Here, the low-melting-point material film 5 is made of a low-melting-point material that is melted by heat when the semiconductor plate 1 and the insulating substrate 2 are anodic bonded. In the manufacturing process of the acceleration sensor, the semiconductor plate 1 and the insulating substrate 2 are provided with conductive pads 7a and 7b and an insulating film 8 on the semiconductor plate 1, as shown in FIG. Anodic bonding is performed with the conductive extraction films 4 a and 4 b, the low melting point material film 5, and the fixed electrode 6 formed. The low melting point material film 5 is melted by the heat at this time, and is in close contact with and connected to the conductive pads 7a and 7b.

  The fixed electrode 6 and the conductive extraction film 4a are electrically connected via the conductive pad 7a and the low melting point material film 5, and the semiconductor plate 1 and the conductive extraction film 4b are connected to the conductive pad 7b and the low melting point material film. 5 is electrically connected. As a result, the capacitance between the fixed electrode 6 and the semiconductor plate 1 is extracted from the acceleration sensor as an electrical signal to the conductive extraction films 4a and 4b. By connecting the conductive extraction films 4a and 4b to an external circuit or the like by wire bonding or the like, this electric signal is sent to the external circuit.

  In this way, when the insulating substrate 2 and the semiconductor plate 1 are anodically bonded, the low melting point material film 5 melts and is in close contact with the conductive pads 7a and 7b, so that the conductive pad 7a and the conductive extraction film 4a are connected. The conductive pad 7b and the conductive extraction film 4b are securely connected to each other, and the conduction reliability of the path for taking out an electric signal can be improved.

  For example, in the present embodiment, as shown in FIGS. 3A and 3B, the through holes 2a and 2b are provided in the insulating substrate 2 by blasting. A chipping surface 2c is formed on the semiconductor plate 1 side of 2a and 2b. However, since the low melting point material film 5 formed from the side of the semiconductor plate 1 is also formed on the chipping surface 2c, the conductive pad 7a and the conductive extraction film 4a, and the conductive pad 7b and the conductive extraction film 4b are surely provided. Connected.

  Further, as described above, at the time of anodic bonding of the insulating substrate 2 and the semiconductor plate 1, the conductive pad 7a and the conductive extraction film 4a are connected by the low melting point material film 5, and the fixed electrode 6 and the weight portion 1a of the semiconductor plate 1 are connected. The provided portion can be sealed and kept airtight at the same time, and the manufacturing process of the acceleration sensor can be simplified and the manufacturing cost can be reduced. Further, since the path for taking out the electric signal is constituted by a thin film, even if the temperature changes, almost no thermal stress is generated, and the insulating substrate 2 and the semiconductor plate 1 are deformed to cause the fixed electrode 6 and the weight portion 1a. And the distance between the two is hardly changed, and an electric signal can be appropriately generated according to the acceleration.

  In this embodiment, an Au—Sn alloy can be used as an example of the low melting point material film 5. The Au—Sn alloy has good compatibility with the semiconductor plate 1 and has a melting point of 400 ° C. or less, so that it is easy to melt when the semiconductor plate 1 and the insulating substrate 2 are anodic bonded. Thus, by using an Au-Sn alloy for the low melting point material film 5, the conductive pad 7a and the conductive extraction film 4a can be easily and reliably bonded to the conductive pad 7b and the conductive extraction film 4b, respectively. Is possible.

  FIG. 4 shows an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the second embodiment of the present invention. In the following embodiments, the same functions and shapes as those of the above-described embodiments are denoted by the same reference numerals, and only the portions different from those of the above-described embodiments will be described. The structure in the vicinity of the through-hole 2a connected to the semiconductor substrate 1 and the structure in the vicinity of the through-hole 2b electrically connected to the semiconductor plate 1 will be described using only the diagram showing the structure in the vicinity of the through-hole 2a. In this acceleration sensor, a reverse taper portion 2 d that spreads toward the bonding surface with the semiconductor plate 1 is formed in the through holes 2 a and 2 b formed in the insulating substrate 2. Similar to the above-described embodiment, a low melting point material film 5 is formed on the reverse tapered portion 2d, and the semiconductor plate 1 and the insulating substrate 2 are anodically bonded. At the time of anodic bonding, the low melting point material film 5 is melted and the conductive pad 7a and the conductive extraction film 4a are connected to the conductive pad 7b and the conductive extraction film 4b, respectively. At this time, the low melting point material film 5 remains attached to the reverse taper portion 2d by the wetting force and does not detach.

  In this embodiment, the low melting point material film 5 is stably formed from the upper part to the lower part of the reverse taper part 2d as compared with the case where the reverse taper part 2d is not provided. The film 4a can be connected to the conductive pad 7b and the conductive extraction film 4b, respectively, and the conduction reliability can be improved.

  FIG. 5 shows an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the third embodiment of the present invention. In this embodiment, the low-melting-point material film 5 and the fixed electrode 6 connected to the conductive extraction film 4a are formed as the low-melting-point material fixed electrode 15 using the same material in the above-described embodiment. Since this low melting point material fixed electrode 15 is melted by heat when anodically bonding the semiconductor plate 1 and the insulating substrate 2 and is in close contact with the conductive pad 7a, the low melting point material fixed electrode 15 and the conductive pad 7a are connected. And the conductive extraction film 4a can be reliably connected. In the above-described embodiment, the low melting point material film 5 and the fixed electrode 6 are formed by separate manufacturing processes. However, these can be formed at the same time, and the manufacturing process of the acceleration sensor is simpler. Thus, the manufacturing cost can be reduced.

  FIG. 6 shows an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the fourth embodiment of the present invention. This acceleration sensor includes conductive pads 17a and 17b formed using a low melting point material that melts during the anodic bonding described above. When the semiconductor plate 1 and the insulating substrate 2 of this acceleration sensor are anodically bonded, the low melting point material film 5 and the conductive pads 17a and 17b are melted by heat and securely connected to each other, so that the conduction reliability is further improved. Is possible. Further, since the conductive pad 17a is melted and joined to the vicinity of the through hole 2a on the lower surface of the insulating substrate 2, the portion where the fixed electrode 6 and the weight portion 1a of the semiconductor plate 1 are provided can be more reliably sealed. It becomes. The low melting point material of the conductive pads 17a and 17b may be the same material as the low melting point material film 5 or may be different from each other.

  FIG. 7 shows an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the fifth embodiment of the present invention. In this acceleration sensor, the conductive substrate films 4a and 4b are not formed on the insulating substrate 2, and only the fixed electrode 6 and the low melting point material film 5 are formed, and the insulating substrate 2 and the semiconductor plate 1 are anodically bonded. Thereafter, conductive extraction films 4 a and 4 b are formed on the upper surface of the insulating substrate 2. The conductive extraction film 4a can be formed so as to surely overlap the conductive pad 7a and the low melting point material film 5, and the conductive extraction film 4b can be surely overlapped with the conductive pad 7b and the low melting point material film 5, respectively. It becomes possible to improve conduction reliability.

  FIG. 8 shows an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the sixth embodiment of the present invention. This acceleration sensor includes donut-shaped conductive pads 27a and 27b in which holes that are coaxial with the through holes 2a and 2b are provided in advance. Since the conductive pads 27a and 27b have a smaller volume than when there is no hole, the parasitic capacitance between the pole of the semiconductor plate 1 and the pole on the fixed electrode 6 side is lowered. As described above, since the parasitic capacitance is reduced, the change characteristic of the electric signal of the acceleration sensor can be improved, for example, the change characteristic of the capacitance with respect to the acceleration of the acceleration sensor approaches linear.

  Further, in the present embodiment, the holes provided in the conductive pads 27a and 27b on the semiconductor plate 1 side and the through holes 2a and 2b on the insulating substrate 2 side are provided at the time of anodic bonding of the semiconductor plate 1 and the insulating substrate 2. The hole and the through hole 2a of the conductive pad 27a and the hole and the through hole 2b of the conductive pad 27b are respectively coaxial, so that the semiconductor plate 1 and the insulating substrate 2 can be easily aligned and the anode It becomes possible to join.

  FIG. 9 shows an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the seventh embodiment of the present invention. In this acceleration sensor, as described above, the low melting point material film 5 uses an Au-Sn alloy, and the insulating substrate 2 has a base 16 made of a conductive material for forming the low melting point material film 5. Is provided to be shared with the fixed electrode 6 in the above embodiment. The base 16 is necessary for forming the low melting point material film 5 with an Au—Sn alloy, and since the base 16 is shared with the fixed electrode 6 in the above embodiment, the fixed electrode 6 is formed. The process can be omitted, and the manufacturing process of the acceleration sensor can be simplified to reduce the manufacturing cost.

  FIG. 10 shows an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the eighth embodiment of the present invention. In this acceleration sensor, wiring 24 is wire-bonded to the conductive pads 7a and 7b, respectively, and an electric signal is directly taken out from the conductive pads 7a and 7b. Since the electrical signal is directly taken out from the conductive pads 7a and 7b as described above, for example, the surface roughness of the inner surface of the through hole 2a or the through hole 2b is large, and the electric resistance of the conductive extraction film 4a or the conductive extraction film 4b is increased. However, it is possible to reliably take out an electric signal by avoiding this, and it is possible to improve conduction reliability.

  FIGS. 11A and 11B show an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the ninth embodiment of the present invention. In this acceleration sensor, as shown in FIG. 11 (b), the periphery of each welded portion of the conductive pads 7a and 7b and the low melting point material film 5 is made of a conductive low melting point material and once melted. It is set as the structure sealed with the melting ball 9 solidified from. As shown in FIG. 11 (a), the acceleration sensor includes the insulating substrate 2 and the semiconductor plate 1 in a state in which substantially spherical molten balls 9 are arranged in advance on the semiconductor plate 1 side of the through holes 2a and 2b. And anodic bonding. At the time of anodic bonding, the molten ball 9 is melted by heat and spreads so as to seal the periphery where the conductive pads 7a and 7b and the low melting point material film 5 are welded as shown in FIG.

  In this way, since the molten ball 9 seals the periphery of the welded portions of the conductive pads 7a and 7b and the low melting point material film 5, the weight of the fixed electrode 6 and the semiconductor plate 1 is improved while further improving the conduction reliability. It becomes possible to more reliably maintain the airtightness of the portion provided with the portion 1a.

  Here, as an example of the molten ball 9, for example, an Sn-based alloy can be used. At this time, when the low melting point material film 5 is made of an Au—Sn alloy as described above, the molten ball 9 is surely welded to the low melting point material film 5 and the conduction reliability is more reliably improved. It becomes possible to obtain the effect of maintaining airtightness.

  FIGS. 12A and 12B show an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the tenth embodiment of the present invention. This acceleration sensor includes two brazing material balls 10 made of a conductive low-melting-point material that are welded to and connected to the conductive extraction films 4a and 4b on the inner surfaces of the through holes 2a and 2b, respectively. The brazing material balls 10 are arranged in advance on the opposite side of the through holes 2a and 2b to the side to be joined to the semiconductor plate 1 at the time of anodic bonding of the insulating substrate 2 and the semiconductor plate 1, respectively. Thus, the brazing material ball 10 is melted and welded to the conductive extraction films 4a and 4b, respectively, and the bump portion 10a protruding from the upper surface of the insulating substrate 2 is formed.

  In this acceleration sensor, as shown in FIG. 12B, by directly bonding the bump portion 10a to the external substrate 20, the conductive extraction films 4a and 4b are respectively formed from the fixed electrode 6 and the semiconductor plate 1 as described above. The extracted electrical signal is directly extracted to the external substrate 20 without using a wiring or the like. By doing so, the resistance of the path when the electric signal is taken out from the conductive extraction films 4a and 4b to the external substrate is reduced, and the attenuation of the electric signal can be reduced.

  FIG. 13 shows an acceleration sensor which is one of the semiconductor microelectromechanical devices according to the eleventh embodiment of the present invention. Unlike the above-described embodiments, this acceleration sensor is not formed with the low melting point material film 5 and has conductive pads 17a and 17b made of a low melting point material. The conductive pads 17a and 17b are melted by heat at the time of anodic bonding between the insulating substrate 2 and the semiconductor plate 1. The conductive pad 17a is welded and connected to the fixed electrode 6 and the conductive extraction film 4a. The semiconductor plate 1 and the conductive extraction film 4b are welded and connected.

  In this way, the conductive pads 17a and 17b are melted, and the fixed electrode 6 and the conductive extraction film 4a are securely connected to the semiconductor plate 1 and the conductive extraction film 4b, respectively, so that the acceleration sensor manufacturing process is simplified. It is possible to improve the conduction reliability.

  Here, in the first to tenth embodiments described above, the semiconductor pads 1 are not provided with the conductive pads 7b, 17b, and 27b, and the semiconductor plate 1 and the low melting point material film 5 are directly joined. It may be. Also at this time, the low melting point material film 5 is melted by heat at the time of anodic bonding of the semiconductor plate 1 and the insulating substrate 2, and the semiconductor plate 1 and the conductive extraction film 4b are reliably electrically connected.

  In addition, this invention is not limited to the structure of said each embodiment, A various deformation | transformation is suitably possible in the range which does not change the range of invention. For example, the semiconductor microelectromechanical device in the present invention is not limited to the above-described uniaxial acceleration sensor, but is, for example, a biaxial or triaxial acceleration sensor, or a thin film is formed on the semiconductor plate 1 as a structure. It may be a pressure sensor. In any of the semiconductor microelectromechanical devices, by configuring the electrical signal extraction structure as described above, it is possible to improve conduction reliability, simplify the manufacturing process, and reduce the manufacturing cost. In addition, the signal extraction structure of the semiconductor microelectromechanical device of the present invention can be applied to all the electrical signal extraction units of the semiconductor microelectromechanical device or only to some of the electrical signal extraction units. It may be applied as appropriate in view of the configuration of the semiconductor microelectromechanical device, its manufacturing process, manufacturing cost, and the like.

(A) is a top view of the insulating substrate 2 of the semiconductor microelectromechanical device according to the first embodiment of the present invention, and (b) is a top view of the semiconductor plate 1 in a state where the insulating substrate 2 of the device is removed. AA line sectional view of Drawing 1 (b). (A) is sectional drawing which shows after joining of the semiconductor board 1 and the insulated substrate 2 of the signal extraction structure of a device same as the above, (b) is sectional drawing which shows those joining. Sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 3rd Embodiment of this invention. Sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 4th Embodiment of this invention. Sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 5th Embodiment of this invention. Sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 6th Embodiment of this invention. Sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 7th Embodiment of this invention. Sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 8th Embodiment of this invention. (A) is sectional drawing which shows before joining of the semiconductor board 1 of the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 9th Embodiment of this invention, and the insulated substrate 2, (b) is sectional drawing which shows those joining Figure. (A) is sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 10th Embodiment of this invention, (b) is a cross section which shows when this semiconductor microelectromechanical device is connected with the external substrate 20. Figure. Sectional drawing which shows the signal extraction structure of the semiconductor microelectromechanical device which concerns on the 11th Embodiment of this invention.

Explanation of symbols

1 Semiconductor Plate 1a Weight (Structure)
1b Beam (structure)
2, 3 Insulating substrate 2a, 2b Through hole 2d Reverse taper part 4a, 4b Conductive extraction film 5 Low melting point material film 6 Fixed electrode 7a, 7b, 17a, 17b, 27a, 27b Conductive pad 8 Insulating film 9 Molten ball 10 Brazing material Ball 10a Bump part 16 Base 20 External substrate 24 Wiring

Claims (12)

An insulating substrate provided with a through-hole, a semiconductor plate that forms a movable structure and is anodically bonded to one surface of the insulating substrate, and is provided on a bonding surface between the semiconductor plate and the insulating substrate. A fixed electrode that generates an electrical signal in response to movement, a conductive pad that is bonded to the fixed electrode and / or a semiconductor plate that is a pair of the fixed electrode and is provided in the vicinity of the through hole, and a fixed electrode that is bonded to the fixed electrode An insulating film provided between the formed conductive pad and the semiconductor plate, and a conductive extraction film formed in the vicinity of the through hole and on the inner surface of the through hole and connected to the conductive pad or the semiconductor plate to extract an electrical signal to the outside A signal extraction structure of a semiconductor microelectromechanical device comprising:
In the vicinity of the through-hole on the surface of the insulating substrate to be joined to the semiconductor plate, a conductive low melting point material film is provided in advance so as to partially overlap the conductive extraction film,
When the insulating substrate and the semiconductor plate are anodically bonded, the low melting point material film is melted by heat at the time of the anodic bonding and is connected in close contact with the conductive pad or the semiconductor plate. A signal extraction structure for a semiconductor microelectromechanical device.   2. The signal extraction structure for a semiconductor microelectromechanical device according to claim 1, wherein the through hole has a reverse taper portion that extends toward a bonding surface between the insulating substrate and the semiconductor plate.   2. The signal extraction structure for a semiconductor microelectromechanical device according to claim 1, wherein the fixed electrode and the low melting point material film are formed using the same material.   2. The signal of a semiconductor microelectromechanical device according to claim 1, wherein the conductive pad is made of a conductive low melting point material that is melted by heat of anodic bonding when the insulating substrate and the semiconductor plate are anodic bonded. Extraction structure.   2. The signal extraction structure for a semiconductor microelectromechanical device according to claim 1, wherein the conductive extraction film is formed after the insulating substrate and the semiconductor plate are bonded.   2. The semiconductor microelectronic machine according to claim 1, wherein the conductive pad is of a donut shape in which a hole that is coaxial with the through hole is provided in advance when the insulating substrate and the semiconductor plate are joined. Device signal retrieval structure.   The signal extraction structure for a semiconductor microelectromechanical device according to claim 1, wherein the low melting point material film is made of an Au-Sn alloy. A base made of a conductive material for forming a low melting point material film on the insulating substrate;
8. The signal extraction structure for a semiconductor microelectromechanical device according to claim 7, wherein the base is configured to be shared with the fixed electrode.   2. A signal extraction structure for a semiconductor microelectromechanical device according to claim 1, wherein an electric signal is extracted to the outside by wire bonding directly to the conductive pad. Arranging in advance a molten ball made of a conductive low-melting-point material on the side to be bonded to the semiconductor plate of the through hole,
When the insulating substrate and the semiconductor plate are anodically bonded, the molten ball is melted by the heat of the anodic bonding, and the periphery of the welded portion between the conductive pad and the low melting point material film is sealed. The signal extraction structure of a semiconductor microelectromechanical device according to claim 1. The low melting point material film is made of an Au-Sn alloy,
11. The signal extracting structure for a semiconductor microelectromechanical device according to claim 10, wherein the molten ball is made of an Sn-based alloy. A brazing material ball made of a conductive low melting point material is disposed in advance on the opposite side of the through hole to the side to which the semiconductor plate is bonded,
When the insulating substrate and the semiconductor plate are anodic bonded, the brazing material balls are melted by the heat of anodic bonding and welded to the conductive extraction film, and a bump portion protruding from the insulating substrate is formed,
8. The signal extracting structure for a semiconductor microelectromechanical device according to claim 7, wherein an electric signal can be taken out to the external substrate by directly bonding the bump portion to the external substrate.

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