JP2012242223A - Mems device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a MEMS device which can reduce an influence of static electricity from the outside on a MEMS element having a movable part in order to improve the credibility.SOLUTION: A MEMS device includes a MEMS element having a fixed part and a movable part, a first cap covering a movable part with a predetermined interval and fixed to the MEMS element at the fixed part, and a first ground pad electrically connected to the first cap through a conductive member, arranged on the fixed part, and receiving a supply of ground potential.

Description

  The present invention relates to a MEMS device, and more particularly to a MEMS device capable of reducing the influence of static electricity on a movable part.

  In recent years, various electronic devices have been reduced in size, weight, functionality, and functionality, and electronic components to be mounted have been required to have higher density. In response to such demands, an increasing number of electronic components are manufactured as semiconductor devices. For this reason, in addition to the semiconductor device manufactured as a circuit element, various sensors are also manufactured as a semiconductor device to reduce the size and weight. For example, as a product in the field of MEMS (Micro Electro Mechanical Systems), a movable part that is displaced according to an external force is formed on a semiconductor substrate, and a mechanical quantity sensor, a cantilever, Actuators using electric power have been put into practical use.

  As the above-mentioned mechanical quantity sensor, for example, a piezoresistive acceleration sensor that detects the displacement of the movable portion that is displaced according to an external force as a change in the resistance value of the piezoresistive element, or the displacement of the movable portion as a change in capacitance A capacitance type acceleration sensor to be detected may be mentioned, but these MEMS elements are sealed with a cap, a resin, or the like in order to prevent external damage or resin intrusion. The MEMS element sealed with a cap is further sealed as necessary, mounted on a circuit board, and used as an electronic component.

  In a conventional acceleration sensor manufacturing process, when an upper cap and a lower cap made of a glass substrate are fixed to a sensor made of a silicon substrate by anodic bonding and the sensor is hermetically sealed with the upper cap and the lower cap, the sensor and the upper cap Since a high voltage is applied between the upper and lower caps, static electricity is generated between the movable part of the sensor and the upper and lower caps, and the movable part is attracted to the upper or lower cap side, and the movable part is stuck. There was a problem that occurred. With respect to this problem, for example, in Patent Document 1, even when a minute unevenness is provided on the surface of the upper cap and the lower cap facing the sensor and anodic bonding is performed during manufacture, the upper cap or the movable cap of the sensor A structure of a semiconductor acceleration sensor using a piezoresistive element that prevents sticking to a lower cap is disclosed. Further, in Patent Document 2, a conductive shield film that undergoes ductile deformation is provided on the inner surface of the cap that seals the sensor, and the shield film and the movable part of the sensor are electrically connected to each other. There has been disclosed a capacitive acceleration sensor that prevents the generation of static electricity even when the MEMS element and the cap are anodically bonded by setting the movable portion to the same potential.

JP-A-9-166618 JP 2007-85747 A

  As disclosed in Patent Document 1 and Patent Document 2 described above, conventionally, studies have been made to prevent the influence of static electricity generated by anodic bonding between glass and silicon during the manufacture of the acceleration sensor on the movable part of the sensor. It has been. However, countermeasures against external static electricity at the time of sealed packaging, inspection, or use have not been studied, and countermeasures have been desired. Due to such external static electricity, the MEMS element may malfunction and the reliability of the apparatus may be reduced.

  It is an object of the present invention to provide a highly reliable MEMS device by reducing the influence of external static electricity on a MEMS element having a movable part.

  A MEMS device according to an embodiment of the present invention includes a MEMS element having a fixed part and a movable part, a first cap that covers the movable part at a predetermined interval and is fixed to the MEMS element by the fixed part, and a first cap, And a first ground pad electrically connected by a conductive member, disposed on the fixed portion, and supplied with a ground potential. According to this MEMS device, the influence of the static electricity from the outside with respect to the movable part of a MEMS element can be reduced, and the reliability of a device can be improved.

  A MEMS device according to an embodiment of the present invention includes a MEMS element having a fixed part and a movable part, an IC that covers the movable part at a predetermined interval and is fixed to the MEMS element on the fixed part, and an IC and a conductive member. And a first ground pad that is electrically connected, disposed on the fixed portion, and supplied with a ground potential. According to this MEMS device, the influence of the static electricity from the outside with respect to the movable part of a MEMS element can be reduced, and the reliability of a device can be improved.

  A MEMS device according to an embodiment of the present invention includes a substrate having a first ground pad to which a ground potential is supplied, a MEMS element disposed on the substrate and having a fixed portion and a movable portion, with a predetermined interval. An IC is provided that covers the movable portion, is fixed to the MEMS element on the fixed portion, and is electrically connected to the first ground pad by a conductive member. According to this MEMS device, the influence of the static electricity from the outside with respect to the movable part of a MEMS element can be reduced, and the reliability of a device can be improved.

  A MEMS device according to an embodiment of the present invention includes a substrate, a sealing cap that is fixed to the substrate and forms a hollow space together with the substrate, and an IC and a MEMS element disposed in the hollow space, and is sealed A conductive film is arranged on at least one of the inside and the outside of the cap. According to this MEMS device, the influence of the static electricity from the outside with respect to the movable part of a MEMS element can be reduced, and the reliability of a device can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the MEMS device which can reduce the influence of the static electricity from the outside with respect to the MEMS element which has a movable part, and can improve reliability can be provided.

It is an example of the perspective view which looked at the acceleration sensor device which concerns on the 1st Embodiment of this invention from the top. It is an example of the perspective view which looked at another acceleration sensor device which concerns on 1st Embodiment of this invention from the top. (A) It is an example of sectional drawing along the AA line of the acceleration sensor device shown to FIG. 1A. (B) It is an example of sectional drawing along the AA line of the acceleration sensor device 100 shown to FIG. 1A. It is an example of the perspective view which looked at another acceleration sensor device which concerns on the 1st Embodiment of this invention from the top. (A) It is an example of sectional drawing along the AA line of the acceleration sensor device shown in FIG. (B) It is an example of sectional drawing along the AA line of the acceleration sensor device 300 shown in FIG. (A) It is an example of sectional drawing of another acceleration sensor device which concerns on the 1st Embodiment of this invention. (B) It is an example of sectional drawing of another acceleration sensor device which concerns on the 1st Embodiment of this invention. It is an example of the perspective view which looked at the acceleration sensor device which concerns on the 2nd Embodiment of this invention from the top. It is sectional drawing along the AA line of the acceleration sensor device shown in FIG. It is sectional drawing of another acceleration sensor device which concerns on the 2nd Embodiment of this invention. It is an example of the perspective view which looked at the acceleration sensor device which concerns on the 3rd Embodiment of this invention from the top. It is an example of sectional drawing along the AA line of the acceleration sensor device shown in FIG. It is an example of sectional drawing of another acceleration sensor device which concerns on the 3rd Embodiment of this invention. It is an example of the perspective view which looked at the acceleration sensor device which concerns on the 4th Embodiment of this invention from the top. It is an example of sectional drawing along the AA line of the acceleration sensor device shown in FIG. It is an example of the perspective view which looked at another acceleration sensor device which concerns on the 4th Embodiment of this invention from the top. It is an example of sectional drawing along the AA line of the acceleration sensor device shown in FIG. It is an example of the perspective view which looked at another acceleration sensor device which concerns on the 4th Embodiment of this invention from the top. It is an example of sectional drawing along the AA line of the acceleration sensor device shown in FIG. It is an example of sectional drawing of the acceleration sensor device which concerns on the 5th Embodiment of this invention.

  The present inventor brings a charged object charged by static electricity from the outside close to a triaxial piezoresistive acceleration sensor package including a sensor whose movable part is covered by an upper cap and a lower cap. It was discovered that the weight part of the structure moves due to the static electricity of the charged object. This is presumably because the cap covering the movable part of the sensor is in an electrically floating state, so that the cap is charged by the static electricity of the charged object, and the weight part of the sensor is pulled by the charged cap. The movement of the weight portion of the sensor caused by the charged object causes a malfunction even in a device other than a device using electrostatic capacity or electrostatic attraction, and decreases the reliability of the device. Therefore, the present inventor has reached the present invention as a result of examining the configuration of a MEMS device having a movable part that can reduce the influence of external static electricity. A MEMS device capable of reducing the influence of static electricity on a device including a MEMS element and improving reliability is disclosed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment described below, a MEMS device in the case of using a triaxial acceleration sensor mainly using a piezoresistive element as the MEMS element will be described. However, the present invention is not limited to a three-axis acceleration sensor using a piezoresistive element as a MEMS element, but also a piezo type, piezoelectric type, heat detection type, FET type acceleration sensor or gyro having a movable portion that is displaced according to an external force. The present invention can also be applied to the case of using other elements using a sensor and MEMS technology, such as a geomagnetic sensor, a micromirror, and an RF switch, and various modifications are possible.

  A schematic configuration of the acceleration sensor devices 100 and 100 'according to the first embodiment of the present invention will be described with reference to FIGS. 1A, 1B, and 2. FIG. FIG. 1A is an example of a perspective view of the acceleration sensor device 100 according to the first embodiment of the present invention as viewed from above. The acceleration sensor device 100 according to the first embodiment of the present invention includes a wiring board 102, an IC 104 arranged on the wiring board 102, and a sensor package 105 arranged on the IC 104. The sensor package 105 includes a sensor 106, an upper cap 108, a terminal 118, a GND pad 112, and a conductive paste 114. The sensor package 105 may include a lower cap 110 disposed between the IC 104 and the sensor 106. Since the lower cap 110 is disposed below the sensor 106, the illustration thereof is omitted in FIG. 1A. When the sensor 106 is directly disposed on the IC 104, the lower cap 110 may be omitted.

  The sensor 106 includes a weight portion 106a, a flexible portion 106b connected to the weight portion 106a, a fixed portion 106c connected to the flexible portion 106b, and a displacement portion of the weight portion 106a disposed in the flexible portion 106b. And a plurality of piezoresistive elements (not shown) that detect in the three-axis directions, a terminal 118 and a GND pad 112 disposed on the fixed portion 106c. The sensor 106 includes a weight portion 106a and a flexible portion 106b that are movable with respect to the fixed portion 106c by an external force. Hereinafter, a portion that is movable with respect to the fixed portion 106c may be referred to as a movable portion 106d. When acceleration is applied to the sensor 106, the weight portion 106a is displaced, and the flexible portion 106b is bent along with this displacement. When the flexible portion 106b bends, a force is applied to the piezoresistive element disposed in the flexible portion 106b, and the resistance value of the piezoresistive element changes. The change in resistance value is detected, and the magnitude and direction of acceleration applied to the sensor 106 are detected. A signal from the sensor 106 is transmitted to the IC 104 through the wiring 120 from the terminal 118 disposed on the fixed portion 106 c of the sensor 106. A signal from the IC 104 is transmitted from the wiring substrate 102 to the outside through the wiring 124 from the terminal 122 of the IC 104.

  The upper cap 108 covers the movable portion 106d of the sensor 106 with a predetermined interval, restricts excessive displacement of the movable portion 106d of the sensor 106 in the upward direction, and prevents the movable portion 106d from being damaged. The upper cap 108 is fixed to the fixing portion 106c. The lower cap 110 is disposed at a predetermined interval from the movable portion 106d, restricts excessive displacement of the sensor 106 in the downward direction of the movable portion 106d, and prevents the movable portion 106d from being damaged. The lower cap 110 is fixed to the fixing portion 106c. The upper cap 108 and the lower cap 110 are fixed to the sensor 106 by bonding with an adhesive, direct bonding, or the like to the fixing portion 106c. The lower cap 110 may be omitted. When the lower cap 110 is omitted, the IC 104 disposed under the sensor 106 may limit excessive displacement of the sensor 106 in the downward direction of the movable part 106d to prevent the movable part 106d from being damaged. . The upper cap 108 and the lower cap may be, for example, a semiconductor such as Si, glass, plastic, rubber, and the like, and are not particularly limited as long as the movable portion 106d can be prevented from being damaged.

  FIG. 1B is an example of a perspective view of another acceleration sensor device 100 ′ according to the first embodiment of the present invention. In the acceleration sensor device 100 ′ illustrated in FIG. 1B, the same or similar elements as those in the acceleration sensor device 100 illustrated in FIG. 1A are denoted by the same reference numerals, and redundant description is omitted.

  The acceleration sensor device 100 ′ includes a wiring board 102, an IC 104 and a sensor package 105 arranged on the wiring board 102. The sensor package 105 includes a sensor 106, an upper cap 110, a terminal 118, a GND pad 112, and a conductive paste 114. The sensor package 105 may include a lower cap 110 disposed between the wiring board 102 and the sensor 106. Since the lower cap 110 is disposed below the sensor 106, the illustration thereof is omitted in FIG. 1B. The acceleration sensor device 100 ′ has the same configuration as the acceleration sensor device 100 shown in FIG. 1A except that the IC 104 and the sensor package 105 are arranged on the wiring board 102 side by side.

  FIG. 2A is a cross-sectional view taken along line AA of the acceleration sensor device 100 shown in FIG. 1A. In FIG. 2A, only the configuration of the sensor package 105 is shown, and elements such as the wiring board 102, IC 104, terminals, and wiring are omitted.

  Referring to FIGS. 1A and 2A, the GND pad 112 and the upper cap 108 arranged in the sensor fixing portion 106c are electrically connected by a conductive paste 114, and the upper cap 108 is connected to the GND potential. Become. As the conductive paste 114, it is preferable to use a soft material. By using a soft material for the conductive paste 114, the influence of stress on the sensor 106 can be reduced. As such a conductive paste 114, a paste having a flexural modulus of 5 GPa or less is preferably used. The conductive paste 114 may be Au, Ag, Pd, Ni, Cu, Sn, Ag-coated Cu, silicone-based conductive paste, or the like. Further, as the conductive paste 114, Sn, Sn—Pb, Sn—Ag, Sn—Zn, Bi, or Sn—Ag—Cu solder materials may be used.

  In the acceleration sensor device 100, the GND pad 112 is disposed on the fixed portion 106c of the sensor 106, the GND pad 112 and the upper cap 108 are electrically connected by the conductive paste 114, and the potential of the upper cap 108 is set to the GND potential. As a result, even when a charged object charged with static electricity approaches the sensor package 105 from the outside, electric charges are less likely to accumulate in the upper cap 108, making it difficult to be charged. Since the upper cap 108 is less likely to be charged, the movable portion 106d of the sensor 106 can be prevented from moving by being pulled by the upper cap 108, and the reliability of the acceleration sensor device can be improved. Note that the sensor package 105 of the acceleration sensor device 100 ′ illustrated in FIG. 1B also has the same configuration as the sensor package 105 illustrated in FIG.

  Further, in the acceleration sensor devices 100 and 100 ′, as shown in FIG. 2B, the bump 126 is disposed on the GND pad 112, the conductive paste 114 is disposed on the bump 126, and the GND pad 112 and the upper cap are disposed. 108 may be electrically connected. The bump 126 may include a metal material such as gold, aluminum, and aluminum silicon. The bump 126 preferably includes gold with low contact resistance. Further, when the GND pad 112 is made of aluminum, the bump 126 preferably contains gold because the bonding strength with gold is high. The conductive paste 114 can be arranged on the bump 126 by a known method such as a dispensing method. By disposing the bump 126 on the GND pad 112, the material of the dispensed conductive paste 114 can be prevented from spreading and coming into contact with the terminals 118 other than the GND pad 112. Furthermore, it is preferable that the bump 126 has a shape in which a part of the bump 126 projects in a convex shape. This is because the conductive paste 114 is reliably disposed on the GND pad through the convex portion.

  In addition to electrically connecting the upper cap 108 of the sensor package 105 to the GND pad 112 to set the potential of the upper cap 108 to the GND potential, the lower cap 110 may also be set to the GND potential. Hereinafter, the configuration of the acceleration sensor device when the potential of not only the upper cap 108 but also the lower cap 110 is set to the GND potential will be described.

  A schematic configuration of another acceleration sensor device 300 according to the first embodiment of the present invention will be described with reference to FIGS. 3, 4A, and 4B. FIG. 3 is an example of a perspective view of another acceleration sensor device 300 according to the first embodiment of the present invention as seen from above. In the acceleration sensor device 300 shown in FIG. 3, the same or similar elements as those in the acceleration sensor device 100 shown in FIG. 1A are assigned the same reference numerals, and redundant descriptions are omitted.

  The acceleration sensor device 300 according to the first embodiment of the present invention includes a wiring substrate 102, an IC 104 disposed on the wiring substrate 102, and a sensor package 301 disposed on the IC 104. The sensor package 301 includes a sensor 106, an upper cap 108, a lower cap 110, a GND pad 112, a terminal 118, a conductive paste 114, and a conductive paste 302. Since the lower cap 110 is disposed on the lower side of the sensor 106, the illustration is omitted in FIG. In the acceleration sensor device 300, the upper cap 108 and the lower cap 110 that are electrically connected to the GND pad 112 are electrically connected by the conductive paste 302.

FIG. 4A is a cross-sectional view taken along line AA of the acceleration sensor device 300 shown in FIG. In FIG. 4A, only the configuration of the sensor package 301 is shown, and elements such as the wiring board 102, IC 104, terminals, and wiring are omitted.

  Referring to FIGS. 3 and 4A, the GND pad 112 and the upper cap 108 arranged in the sensor fixing portion 106c are electrically connected by the conductive paste 114, and the upper cap 108 is connected to the GND potential. Become. Further, the upper cap 108 and the lower cap 110 are electrically connected via the conductive paste 302. For the conductive paste 302, a material similar to that of the conductive paste 114 can be used.

  The position where the conductive paste 302 is disposed is not particularly limited as long as a desired electrical connection can be obtained. Considering the stress generated when the conductive paste 302 is cured, it is preferable to dispose the conductive paste 302 on the side surface of the sensor with an area as small as possible. In addition, it is preferable to arrange so as to exclude the virtual straight line set so as to connect both connection ends of each flexible portion 106b in a plan view because the influence of the stress applied to the flexible portion 106b by the conductive paste 302 is small. Alternatively, the conductive paste 302 may be disposed at a position facing the conductive paste 114 to balance the stress. The conductive paste 302 is preferably arranged so that the upper cap 106, the sensor 106, and the lower cap 110 are electrically connected at least at one location on the side surface of the sensor 106, but a plurality of conductive pastes are added to the side surface of the sensor 106. May be arranged. The additionally disposed conductive paste may contribute to electrical connection, or may be a dummy that does not contribute to electrical connection. For example, a conductive paste may be disposed on each of the four side surfaces of the sensor 106 to balance the stress.

  In the acceleration sensor device 300 shown in FIG. 3 and the sensor package 301 shown in FIG. 4A, the GND pad 112 is disposed on the fixing portion 106c of the sensor 106, and the GND pad 112 and the upper cap 108 are connected by the conductive paste 114. By electrically connecting the upper cap 108 and the lower cap 110 with the conductive paste 302, the potential of the upper cap 108 and the lower cap 110 can be set to the GND potential. As a result, even when a charged object charged with static electricity approaches the sensor package 301 from the outside, electric charges are less likely to be accumulated in the upper cap 108 and the lower cap 110, and charging is difficult. Since the upper cap 108 and the lower cap 110 are less likely to be charged, it is possible to prevent the movable portion 106d of the sensor 106 from being pulled and moved by the upper cap 108 and the lower cap 110, thereby improving the reliability of the acceleration sensor device. It becomes possible to improve. Further, the potential of the upper cap 108 and the lower cap 110 may be set to the GND potential, and the potential of the fixing portion 106c of the sensor 106 may be set to the GND potential by the conductive paste 302. In the acceleration sensor device 300 shown in FIG. 3, the sensor package 301 is arranged on the IC 104. However, like the acceleration sensor device 100 ′ shown in FIG. 1B, the IC 104 and the sensor package 301 are arranged side by side. May be. Even when the IC 104 and the sensor package 301 are arranged side by side, the sensor package 301 has the same configuration as that shown in FIG. 4A, and the potentials of the upper cap 108 and the lower cap 110 are set to the GND potential. be able to.

  Further, in the acceleration sensor device 300, as shown in FIG. 4B, the sensor package 301 may include a bump 126 disposed on the GND pad 112, and the conductive paste 114 is disposed on the bump 126. The GND pad 112 and the upper cap 108 may be electrically connected. By disposing the conductive paste 114 on the bump 126, the conductive paste 114 can be prevented from coming into contact with the terminals 118 other than the GND pad 112.

  As in the acceleration sensor device 300 shown in FIGS. 3 and 4A and 4B, the upper cap 108 electrically connected to the GND pad 112 is electrically connected to the lower cap 110 by the conductive paste 302. Thus, not only the upper cap 108 but also the potential of the lower cap 110 may be set to the GND potential. In the acceleration sensor device 300 shown in FIGS. 3 and 4A and 4B, not only the upper cap 108 and the lower cap 110 but also the potential of the fixing portion 106c of the sensor 106 in contact with the conductive paste 302 becomes the GND potential. .

  5A and 5B are schematic cross-sectional views of another acceleration sensor device 500 according to the first embodiment of the present invention. The perspective view of the acceleration sensor device 500 viewed from above is substantially the same as that shown in FIG. In the acceleration sensor device 500 shown in FIGS. 5A and 5B, the same or similar elements as those in the acceleration sensor device 100 shown in FIG. 1A are given the same reference numerals, and redundant descriptions are omitted.

  The acceleration sensor device 500 includes a wiring board 102, an IC 104 disposed on the wiring board 102 and having a GND pad 504, and a sensor package 501 disposed on the IC 104. The sensor package 501 includes a sensor 106, an upper cap 108, a lower cap 110, a GND pad 112, a terminal 118, a conductive paste 114, and a conductive paste 506 that electrically connects the GND pad 504 and the lower cap 110. 5A and 5B, only the configuration of the sensor package 501 and the IC 104 of the acceleration sensor device 500 is shown, and elements such as the wiring board 102, terminals, and wiring are omitted.

  In FIG. 5A, the GND pad 112 is disposed on the fixing portion 106c of the sensor 106, the GND pad 112 and the upper cap 108 are electrically connected by the conductive paste 114, and the potential of the upper cap 108 is changed to the GND potential. To do. Furthermore, by arranging the GND pad 504 on the IC 104 and electrically connecting the lower cap 110 and the GND pad 504 with the conductive paste 506, the potential of the lower cap 110 can be set to the GND potential. As a result, even if a charged object that is charged with static electricity from the outside approaches the sensor package 501, electric charges are less likely to be accumulated in the upper cap 108 and the lower cap 110, and charging is difficult. Since the upper cap 108 and the lower cap 110 are less likely to be charged, it is possible to prevent the movable portion 106d of the sensor 106 from being pulled and moved by the upper cap 108 and the lower cap 110, thereby improving the reliability of the acceleration sensor device. It becomes possible to improve.

  As shown in FIG. 5B, the bump 126 is disposed on the GND pad 112 disposed on the fixing portion 106c of the sensor 106, the conductive paste 114 is disposed on the bump 126, and the GND pad 112 and the upper cap are disposed. 108 may be electrically connected. By disposing the conductive paste 114 on the bump 126, the conductive paste 114 can be prevented from coming into contact with the terminals 118 other than the GND pad 112.

  Although not shown, in the acceleration sensor device 500 shown in FIGS. 5A and 5B, the conductive paste 506 that electrically connects the lower cap 110 and the GND pad 504 is extended to the upper cap 108 to The cap 108 and the GND pad 504 may be electrically connected.

(Embodiment 2)
A schematic configuration of an acceleration sensor device 600 according to a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is an example of a perspective view of the acceleration sensor device 600 according to the second embodiment of the present invention as viewed from above. In the acceleration sensor device 600 shown in FIG. 6, the same or similar elements as those in the acceleration sensor device 100 shown in FIG. 1A are denoted by the same reference numerals, and redundant description is omitted.

  The acceleration sensor device 600 according to the second embodiment of the present invention includes a wiring board 102, an IC 104 disposed on the wiring board 102, and a sensor package 601 disposed on the IC 104. The sensor package 601 is disposed on the sensor 106, the upper cap 108, the GND pad 602 disposed on the fixing portion 106 c of the sensor 106, and the GND pad 602, and the conductive adhesive 604 that bonds the sensor 106 and the upper cap 108. including. The conductive adhesive 604 is preferably made of a soft material. For example, Au, Ag, Pd, Ni, Cu, Sn, Ag-coated Cu, silicone-based conductive paste, n, Sn-Pb-based, Sn-- It may be Ag-based, Sn-Zn-based, Bi-based, Sn-Ag-Cu-based solder, or the like. By using a soft material for the conductive adhesive 604, the influence of stress on the sensor 106 can be reduced. The sensor package 601 may include a lower cap 110 disposed between the IC 104 and the sensor. Since the lower cap 110 is disposed below the sensor 106, the illustration thereof is omitted in FIG. Note that when the sensor 106 is directly disposed on the IC 104, the lower cap 110 may be omitted.

  FIG. 7 is a cross-sectional view taken along line AA of the acceleration sensor device 600 shown in FIG. In FIG. 7, only the configuration of the sensor package 601 is shown, and elements such as the wiring board 102, the IC 104, terminals, and wiring are omitted. In the sensor package 601 shown in FIGS. 6 and 7, the upper cap 108 is formed by a conductive adhesive 604 that is disposed on the GND pad 602 disposed on the fixing portion 106 c of the sensor 106 and bonds the sensor 106 and the upper cap 108. Are electrically connected to the GND pad 602 to set the potential of the upper cap 108 to the GND potential. As a result, even if a charged object charged with static electricity approaches the sensor package 601 from the outside, it is difficult for electric charges to be accumulated in the upper cap 108 and it is difficult to be charged. Since the upper cap 108 is less likely to be charged, the movable portion 106d of the sensor 106 can be prevented from being pulled and moved by the upper cap 108, and the reliability of the acceleration sensor device can be improved.

  In addition to electrically connecting the upper cap 108 of the sensor package 601 to the GND pad 602 to set the potential of the upper cap 108 to GND, the potential of the lower cap 110 may also be set to GND potential. Hereinafter, the configuration of the acceleration sensor device when the potential of not only the upper cap 108 but also the lower cap 110 is set to the GND potential will be described.

  A schematic configuration of another acceleration sensor device 800 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of another acceleration sensor device 800 according to the second embodiment of the present invention. A perspective view of the acceleration sensor device 800 shown in FIG. 8 as viewed from above is substantially the same as the acceleration sensor device 600 shown in FIG. In the acceleration sensor device 800 shown in FIG. 8, the same or similar elements as those of the acceleration sensor device 600 shown in FIG. In FIG. 8, elements such as the wiring board 102, terminals, and wiring are omitted.

  An acceleration sensor device 800 shown in FIG. 8 includes a wiring board 102, an IC 802 on which a GND pad 804 is arranged, and a sensor package 801 arranged on the IC 802. The sensor package 801 is disposed on the sensor 106, the upper cap 108, the GND pad 602 disposed on the fixing portion 106 c of the sensor 106, and the GND pad 602, and the conductive adhesive 604 that bonds the sensor 106 and the upper cap 108. A lower cap 110. Further, the sensor package 801 includes a conductive adhesive 806 that is disposed on the GND pad 804 and adheres the IC 802 and the sensor package 601. Except for the point that the GND pad 804 of the IC 802 and the lower cap 110 are electrically connected by a conductive adhesive 806, the configuration is substantially the same as that of the acceleration sensor device 600 shown in FIG. According to the present embodiment, the attachment of the sensor 106 to the IC 802 and the potential regulation of the lower cap 110 can be performed simultaneously. For the conductive adhesive 806, a material similar to that of the conductive adhesive 604 may be used.

  In the sensor package 801 shown in FIG. 8, similarly to the sensor package 601 shown in FIG. 6, the conductive package is disposed on the GND pad 602 disposed on the fixing portion 106 c of the sensor 106 and bonds the sensor 106 and the upper cap 108. The upper cap 108 and the GND pad 602 are electrically connected by the adhesive 604, and the potential of the upper cap 108 is set to the GND potential. Further, in the sensor package 801, the lower cap 110 and the GND pad 804 are disposed on the GND pad 804 disposed on the IC 802 by a conductive adhesive 806 that bonds the lower cap 110 of the sensor package 801 and the IC 802. Are electrically connected, and the potential of the lower cap 110 is set to the GND potential. As a result, even if a charged object charged with static electricity approaches the sensor package 801 from the outside, it is difficult for electric charges to accumulate in the upper cap 108 and the lower cap 110, and it becomes difficult to charge. Since the upper cap 108 and the lower cap 110 are less likely to be charged, it is possible to prevent the movable portion 106d of the sensor 106 from being pulled and moved by the upper cap 108 and the lower cap 110, thereby improving the reliability of the acceleration sensor device. It becomes possible to improve.

(Embodiment 3)
A schematic configuration of an acceleration sensor device 900 according to a third embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is an example of a perspective view of the acceleration sensor device 900 according to the third embodiment of the present invention as seen from above. In the acceleration sensor device 900 shown in FIG. 9, the same or similar elements as those in the acceleration sensor device 100 shown in FIG. 1A are denoted by the same reference numerals, and redundant description is omitted.

  An acceleration sensor device 900 according to the third embodiment of the present invention includes a wiring board 102, an IC 104 disposed on the wiring board 102, and a sensor package 901 disposed on the IC 104. The sensor package 901 electrically connects the sensor 106, the upper cap 108, the GND pad 902 disposed on the fixing portion 106c of the sensor 106, the pad 906 disposed on the upper cap 108, and the GND pad 902 and the pad 906. Wiring 904 to be included. The sensor package 901 may include a lower cap 110 disposed between the IC 104 and the sensor 106. Since the lower cap 110 is disposed on the lower side of the sensor 106, the illustration thereof is omitted in FIG. Note that when the sensor 106 is directly disposed on the IC 104, the lower cap 110 may be omitted.

  FIG. 10 is a cross-sectional view taken along line AA of the acceleration sensor device 900 shown in FIG. In FIG. 10, only the configuration of the sensor package 901 is shown, and elements such as the wiring board 102, the IC 104, terminals, and wiring are omitted. In the sensor package 901 shown in FIGS. 9 and 10, the GND pad 902 disposed on the fixing portion 106 c of the sensor 106 and the pad 906 disposed on the upper cap 108 are electrically connected by the wiring 904, thereby The cap 108 and the GND pad 902 are electrically connected so that the potential of the upper cap 108 becomes the GND potential. As a result, even if a charged object charged with static electricity approaches the sensor package 901 from the outside, it is difficult for electric charge to accumulate in the upper cap 108 and it is difficult to be charged. Since the upper cap 108 is less likely to be charged, the movable portion 106d of the sensor 106 can be prevented from being pulled and moved by the upper cap 108, and the reliability of the acceleration sensor device can be improved.

  The wiring board 102 and the IC 104, and the IC 104 and the sensor 106 are usually electrically connected by wire bonding using a metal wiring. In this embodiment, since the pad 906 and the GND pad 902 are electrically connected by the wiring 904, the electrical connection can be simultaneously performed at the time of another wire bonding. Therefore, it can be set as a simpler manufacturing process.

  The upper cap 108 of the sensor 106 and the GND pad 902 may be electrically connected to change the potential of the upper cap 108 to the GND potential, and the potential of the lower cap 110 may be set to the GND potential. Hereinafter, the configuration of the acceleration sensor device when the potential of not only the upper cap 108 but also the lower cap 110 is set to the GND potential will be described.

  A schematic configuration of another acceleration sensor device 1100 according to the third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a cross-sectional view of another acceleration sensor device 1100 according to the third embodiment of the present invention. A perspective view of the acceleration sensor device 1100 shown in FIG. 11 as viewed from above is substantially the same as the acceleration sensor device 900 shown in FIG. In the acceleration sensor device 1100 shown in FIG. 11, the same or similar elements as those in the acceleration sensor device 900 shown in FIG. In FIG. 11, only the configuration of the sensor package 901 ′ is shown, and elements such as the wiring board 102, IC 104, terminals, and wiring are omitted.

  A sensor package 901 ′ shown in FIG. 11 has a GND pad 1102 disposed on the fixing portion 106 c of the sensor 106, and extends a lower cap 110 ′ disposed below the sensor 106. The pad 1106 is disposed on the sensor 106, the GND pad 1102 disposed on the fixing portion 106 c of the sensor 106 and the pad 1106 are electrically connected by the wiring 1104, and the lower cap 110 ′ and the GND pad 1102 are electrically connected. Thus, the sensor package 901 has the same configuration as the sensor package 901 shown in FIG. 10 except that the potential of the lower cap 110 ′ is set to the GND potential. Although not shown, in the sensor package 901 ′ shown in FIG. 11, as with the sensor package 901 shown in FIG. 10, the GND pad 902 arranged on the fixing portion 106 c of the sensor 106 and the pad arranged on the upper cap 108. By electrically connecting 906 to the wiring 904, the upper cap 108 and the GND pad 902 are electrically connected, and the potential of the upper cap 108 is set to the GND potential.

  In the sensor package 901 ′ shown in FIG. 11, the GND pad 902 and the upper cap 108 arranged on the fixing portion 106c of the sensor 106 are electrically connected by the wiring 904, similarly to the sensor package 901 shown in FIG. The potential of the upper cap 108 is set to the GND potential. Further, in the sensor package 901 ′, the GND pad 1102 disposed on the fixing portion 106 c of the sensor 106 and the pad 1106 disposed on the lower cap 110 ′ are electrically connected by the wiring 1104, and the lower cap 110 ′ is electrically connected. The potential is set to the GND potential. As a result, even when a charged object charged with static electricity approaches the sensor package 901 ′ from the outside, charges are not easily accumulated in the upper cap 108 and the lower cap 110 ′, and charging is difficult. Since the upper cap 108 and the lower cap 110 ′ are less likely to be charged, the movable portion 106 d of the sensor 106 can be prevented from moving by being pulled by the upper cap 108 and the lower cap 110 ′. It becomes possible to improve the property.

(Embodiment 4)
A schematic configuration of an acceleration sensor device 1200 according to the fourth embodiment of the present invention will be described with reference to FIGS. 12 and 13. FIG. 12 is an example of a perspective view of an acceleration sensor device 1200 according to the fourth embodiment of the present invention as seen from above. In the acceleration sensor device 1200 shown in FIG. 12, the same or similar elements as those in the acceleration sensor device 100 shown in FIG. 1A are denoted by the same reference numerals, and redundant description is omitted.

  An acceleration sensor device 1200 according to the fourth embodiment of the present invention includes a wiring board 102, a sensor package 1201 disposed on the wiring board 102, and an IC 1202 that covers the sensor package 1201. The sensor package 1201 includes a sensor 106, a GND pad 1204 disposed on the fixing portion 106 c of the sensor 106, a conductive adhesive 1206 disposed on the GND pad 1204 to bond the IC 1202 and the sensor 106, and a GND pad 1214. Including. The IC 1202 has a pad 1208 disposed on the IC 1202. The wiring 1210 electrically connects the pad 1212 and the pad 1208 arranged on the fixing portion 106 c of the sensor 106. The IC 1202 has a pad 1218 disposed on the IC 1202. The GND pad 1214 and the pad 1218 are electrically connected by the wiring 1216. The conductive adhesive 1206 is preferably made of a soft material. For example, Au, Ag, Pd, Ni, Cu, Sn, Ag-coated Cu, silicone-based conductive paste, n, Sn-Pb-based, Sn-- It may be Ag-based, Sn-Zn-based, Bi-based, Sn-Ag-Cu-based solder, or the like. In the acceleration sensor device 1200 according to the fourth embodiment of the present invention, the upper cap of the sensor package 1201 is omitted, and instead of the upper cap, the IC 1202 covers the movable part 106d of the sensor 106 at a predetermined interval. The excessive displacement of the movable portion 106d in the upward direction is limited, and the movable portion 106d is prevented from being damaged. A signal from the sensor 106 is transmitted to the IC 1202 through the pad 1212, the wiring 1210, and the pad 1208. The number of GND pads 1214 is not limited to one, and a plurality of GND pads 1214 may be arranged.

  13 is a cross-sectional view taken along line AA of the acceleration sensor device 1200 shown in FIG. In the sensor package 1201 shown in FIGS. 12 and 13, the IC 1202 and the GND pad 1204 are disposed on the GND pad 1204 disposed on the fixing portion 106 c of the sensor 106, and the conductive adhesive 1206 that bonds the sensor 106 and the IC 1202. And DIE of the IC 1202 can be connected to GND. As a result, the DIE potential becomes the same potential as GND and the potential of the IC is stabilized, so that signal noise can be reduced. Further, the IC 1202 and the GND of the sensor 106 can be connected to each other through the GND pad 1214, the wiring 1216, and the pad 1218. Even if a charged object that is charged with static electricity from the outside approaches the sensor package 1201, it is difficult for the charge to be accumulated in the IC 1202. It becomes difficult to be charged. Since the IC 1202 is less likely to be charged, the movable portion 106d of the sensor 106 can be prevented from moving by being pulled by the upper cap 108, and the reliability of the acceleration sensor device can be improved. Further, according to this embodiment, since the IC 1202 also serves as the upper cap, the acceleration sensor device can be thinned.

  Although not shown in the acceleration sensor device 1200 shown in FIGS. 12 and 13, the sensor package 1201 may include a lower cap 110 that is disposed with a predetermined distance from the movable portion 106 d of the sensor 106. When the lower cap 110 is included, the lower cap 110 and the IC 1202 may be electrically connected via a conductive paste, and the potential of the lower cap 110 may be set to the GND potential, or a separate GND pad may be provided on the wiring board 102. Alternatively, the potential of the lower cap 110 may be set to the GND potential by being electrically connected to the lower cap 110. As a method of connecting the lower cap 110 and a GND pad separately provided on the wiring board 102, the lower cap 110 and the wiring board 102 may be bonded by a conductive adhesive such as solder disposed on the GND pad. The lower cap and the GND pad may be electrically connected with a conductive paste.

  FIG. 14 is an example of a perspective view seen from above of the acceleration sensor device 1400 showing a schematic configuration of another acceleration sensor device 1400 according to the fourth embodiment of the present invention. FIG. 15 is a cross-sectional view taken along line AA of the acceleration sensor device 1400 shown in FIG. In the acceleration sensor device 1400 shown in FIGS. 14 and 15, the same or similar elements as those in the acceleration sensor device 1200 shown in FIGS. 12 and 13 are denoted by the same reference numerals, and redundant description is omitted.

  14 and 15 includes a wiring board 102 having a GND pad 1402, a sensor package 1401 disposed on the wiring board 102, and an IC 1202 covering the sensor package. The sensor package 1401 includes the sensor 106 and bumps 1410 that connect the sensor 106 and the IC 1202. The IC 1202 includes pads 1406a, 1406b, and 1416, and a through electrode 1412 that electrically connects the pad 1406a and the pad 1416. The IC 1202 covers the movable portion 106d of the sensor 106 with a predetermined interval, restricts excessive displacement of the movable portion 106d of the sensor 106 in the upward direction, and prevents the movable portion 106d from being damaged. The GND pad 1402 and the pad 1406a are electrically connected by a wiring 1404. In the acceleration sensor device 1400, the sensor 106 and the IC 1202 are connected by a bump 1410, and a signal from the sensor 106 is formed on the bump 1410, a pad (not shown) connected to the bump 1410, and the IC 1202, and the pad. The signal is transmitted to the IC 1202 through a through electrode (not shown) connected to the first electrode and a pad 1406b connected to the through electrode.

  In the acceleration sensor device 1400 shown in FIGS. 14 and 15, the GND pad 1402 disposed on the wiring substrate 102 and the pad 1406 a disposed on the IC 1202 are electrically connected by the wiring 1404 to be connected to the GND of the IC 1202. It becomes possible to do. Further, the through-electrode 1412 electrically connects the pad 1406a and the pad 1416 connected to the bump 1410 which is disposed on the side opposite to the side where the pad 1406a of the IC 1202 is disposed and is electrically connected to the sensor 106. By doing so, the GND of the substrate 102 and the IC 1202 is connected to the GND of the sensor 106. Further, the DIE potential of the IC 1202 may be set to the GND potential by electrically connecting the bump 1418 connected to the GND of the sensor 106 and the pad 1414 disposed in the IC 1202. As a result, even if a charged object charged with static electricity approaches the sensor package 1401 from the outside, it is difficult for the charge to be accumulated in the IC 1202, and it is difficult to be charged. Since the IC 1202 is less likely to be charged, the movable portion 106d of the sensor 106 can be prevented from moving by being pulled by the upper cap 108, and the reliability of the acceleration sensor device can be improved.

  As described above, the signal from the sensor 106 electrically connects the pad (not shown) electrically connected to the bump 1410 connected to the sensor 106 and the pad 1406b disposed in the IC 1202. Is transmitted to the IC 1202 through a through electrode (not shown). A signal from the IC 1202 is connected to the pad 122 arranged in the IC, the wiring 124 connected to the pad 122, and the wiring 124, and is transmitted to the substrate 102 through the pad 126 arranged in the substrate 102.

  Although not shown in the acceleration sensor device 1400 shown in FIGS. 14 and 15, the sensor package 1401 may include a lower cap 110 that is disposed with a predetermined distance from the movable portion 106 d of the sensor 106. When the lower cap 110 disposed between the substrate 102 and the sensor 106 is included, a separate GND pad is provided on the wiring substrate 102 and electrically connected to the lower cap 110 so that the potential of the lower cap 110 is set to the GND potential. It may be. As a method of connecting the lower cap 110 and a GND pad separately provided on the wiring board 102, the lower cap 110 and the wiring board 102 may be bonded by a conductive adhesive such as solder disposed on the GND pad. Alternatively, the lower cap and the GND pad may be electrically connected with a conductive paste. Alternatively, the potential of the lower cap 110 may be set to the GND potential by electrically connecting the IC 1202 having the GND potential and the lower cap 110 with a conductive paste.

  FIG. 16 is an example of a perspective view seen from above of the acceleration sensor device 1600, showing a schematic configuration of still another acceleration sensor device 1600 according to the fourth embodiment of the present invention. FIG. 17 is a cross-sectional view taken along line AA of the acceleration sensor device 1600 shown in FIG. In the acceleration sensor device 1700 shown in FIGS. 16 and 17, the same or similar elements as those in the acceleration sensor device 1400 shown in FIGS. 14 and 15 are denoted by the same reference numerals, and redundant description is omitted.

  The acceleration sensor device 1600 shown in FIGS. 16 and 17 includes a wiring board 102 having a GND pad 1402, a sensor package 1601 disposed on the wiring board 102, and an IC 1202 that covers the sensor package 1601. The sensor package 1601 includes a sensor 106, bumps 1612 and 1616 that connect the sensor 106 and the IC 1202, and a conductive paste 1602 that is disposed on the GND pad 1402 and connects the GND pad 1402 and the IC 1202. The conductive paste 1602 is Au, Ag, Pd, Ni, Cu, Sn, Ag-coated Cu, silicone-based conductive paste, n, Sn-Pb-based, Sn-Ag-based, Sn-Zn-based, Bi-based, Sn-- Ag-Cu solder may be used. In the acceleration sensor device 1600, the sensor 106 and the IC 1202 are flip-chip (FC) connected by bumps 1612 and 1616. A signal from the sensor 106 may be transmitted to the IC 1202 via a bump 1612 disposed on the fixing portion 106 c of the sensor 106 and a pad 1610 disposed on the IC 1202. A signal from the IC 1202 is transmitted to the sensor 106 by a pad 1614 of the IC 1202 and a bump 1616 connected to the pad 1614. The signal transmitted to the sensor 106 is connected to a wiring (not shown) formed on the fixing portion 106c of the sensor 106 and the wiring, and a pad 1608 and a pad 1608 arranged on the fixing portion 106c of the sensor 106. Are connected to the wiring 1606 and the wiring 1606, and are transmitted to the substrate 102 through the pads 1604 disposed on the substrate 102. Although not shown, a signal from the IC 1202 may be transmitted to the substrate 102 from the DIE side of the IC 1202 via a wiring by providing a through electrode in the IC 1202.

  In the acceleration sensor device 1600 shown in FIGS. 16 and 17, the potential of the DIE of the IC 1202 can be set to the GND potential by electrically connecting the GND pad 1402 and the IC 1202 with the conductive paste 1602. As a result, even if a charged object charged with static electricity approaches the sensor package 1401 from the outside, it is difficult for the charge to be accumulated in the IC 1202, and it is difficult to be charged. Since the IC 1202 is less likely to be charged, the movable portion 106d of the sensor 106 can be prevented from moving by being pulled by the upper cap 108, and the reliability of the acceleration sensor device can be improved. Further, the conductive paste 1602 and the fixing portion 106c of the sensor 106 may be connected, and the potential of the fixing portion 106c of the sensor 106 may be set to the GND potential.

  Although not shown in the acceleration sensor device 1600 shown in FIGS. 16 and 17, the sensor package 1601 is disposed between the substrate 102 and the sensor 106, and is a lower cap disposed with a predetermined distance from the movable portion 106 d of the sensor 106. 110 may be included. When the lower cap 110 disposed between the substrate 102 and the sensor 106 is included, the GND pad 1402 and the lower cap 110 may be connected by the conductive paste 1602 so that the lower cap 110 has a GND potential.

(Embodiment 5)
A schematic configuration of an acceleration sensor device 1800 according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 18 is a cross-sectional view of an acceleration sensor device 1800 according to the fifth embodiment of the present invention. In the acceleration sensor device 1800 shown in FIG. 18, the same or similar elements as those in the acceleration sensor device 100 shown in FIG. 1A are denoted by the same reference numerals, and redundant description is omitted.

  An acceleration sensor device 1800 shown in FIG. 18 includes a wiring board 102, a sealing cap 1802, an IC 104 and a sensor package 1806 arranged in a hollow space formed by the wiring board 102 and the sealing cap 1802. The sensor package 1806 includes an upper cap 108 and a lower cap 110 that cover the sensor 106 and the movable portion 106d of the sensor 106 and restrict the movement of the movable portion 106d in the vertical direction. Further, the sealing cap 1802 is provided with a shield film 1804 that shields the inside thereof. For the sealing cap 1802, plastic, ceramic, or the like can be used.

  The shield film 1804 may be a conductive film, for example, Al, Al-Si, Cr, Ni, Cu, Au, TiN, In, Pt, Ta, W, Ru, Fe, Zn, Mo, Co, TiW. , Zr, Fe—Ni, ITO, Y, Nb, Ag, Hf, Ir, Mg, Pd, Sn, V, Ge, and the like, or an alloy thereof. Further, C, Si or conductive resin may be used. The shield film 1804 is preferably formed of metal in order to prevent moisture from entering. The shield film 1804 may be formed of a single layer or a multilayer using the above-described materials. The shield film 1804 may be formed on the sealing cap 1802 by sputtering, vapor deposition, CVD, metal coating, or the like in the manufacturing process of the sealing cap 1802.

  The sealed cap 1802 shielded by the shield film 1804 is adhered to the wiring substrate 102 with the shield film 1804 inside, and the sensor package 1806 is sealed, so that a charged object charged with static electricity from the outside of the acceleration sensor device 1800 is obtained. Even if they are close to each other, the shield film 1804 shields the static electricity of the charged material, so that charges are not easily accumulated in the upper cap 108 of the sensor package 1806, and charging is difficult. Since the upper cap 108 is less likely to be charged, the weight portion 106a of the sensor 106 can be prevented from being pulled and moved by the upper cap 108, and the reliability of the acceleration sensor device can be improved. In the case where the sealing cap 1802 is made of plastic, the moisture-proof effect can be improved by disposing the shield film 1804.

  Although not shown, in the acceleration sensor device 1800, the shield film 1804 is extended to the outside of the sealing cap 1802 and connected to the GND electrode provided outside, and the potential of the shield film 1804 is set to GND. Good. By setting the potential of the shield film 1804 to GND, the upper cap 108 of the sensor package 1806 is affected by static electricity due to the shield film 1804 having the GND potential even when a charged object charged with static electricity is brought close to the outside of the acceleration sensor device 1800. It becomes difficult to receive. Since the upper cap 108 is not affected by static electricity, it is possible to prevent the movable portion of the sensor 106 from being pulled and moved by the upper cap 108.

  In the present embodiment, an example in which the shield film 1804 is arranged inside the sealing cap 1802 has been described, but the arrangement of the shield film 1804 is not limited thereto. The shield film 1804 only needs to shield the sensor package 1806, and may be disposed outside the sealing cap 1802, or may be disposed so as to entirely surround the sealing cap 1802 and the wiring substrate 102. . Further, the shield film 1804 may be disposed both inside and outside the sealing cap 1802.

(Example)
Hereinafter, the acceleration sensor device of the present invention will be described in more detail with reference to examples. The measurement of the offset voltage when a charged object charged with static electricity is brought close to the acceleration sensor device of the present invention will be described.

  First, the offset voltage was measured with the acceleration sensor package A using a 3.5 mm × 3.5 mm, 1 mm thick piezoresistor as a detection element in a socket in a stationary state. As the movable part of the sensor included in the acceleration sensor package A, a part covered with an upper cap and a lower cap made of silicon was used. At this time, offset voltages at 0G, 0G, and 1G were measured for the X axis, the Y axis, and the Z axis. The offset voltage measured at this time is set as a reference offset voltage.

  Next, the acceleration sensor package A was mounted on a measurement printed board via lead-free solder. The acrylic resin plate charged by rubbing about 20 times on the nonwoven fabric was brought close to the acceleration sensor package A to about 1 mm, and the maximum offset voltage was measured using a measurement pin arranged on the measurement printed board. As a result, the difference between the measured offset voltage and the reference offset voltage of the acceleration sensor package A was 3.2 mV.

  Next, a sample in which the upper cap covering the movable part of the sensor included in the acceleration sensor package was set to the GND potential was created, and this sample was designated as the acceleration sensor package B. In the acceleration sensor package B, the upper cap is bumped and electrically conductive on the GND pad arranged in the sensor fixing portion, similarly to the acceleration sensor device according to the first embodiment of the present invention shown in FIG. The paste was placed, the GND pad and the upper cap were electrically connected, and the upper cap was set to the GND potential. Ag paste was used as the conductive paste. Like the acceleration sensor package A, the acceleration sensor device package B has a size of 3.5 mm × 3.5 mm and a thickness of 1 mm, and was mounted on a measurement printed board via lead-free solder. The acrylic resin plate charged by rubbing about 20 times on the nonwoven fabric was brought close to the acceleration sensor package B to about 1 mm, and the maximum offset voltage was measured using a measuring pin arranged on the printed circuit board for measurement. As a result, the difference between the measured offset voltage of the acceleration sensor package B and the reference offset voltage of the acceleration sensor package A was 1.2 mV.

  Next, a sample in which the upper cap and the lower cap covering the movable part of the sensor included in the acceleration sensor package were set to the GND potential was created, and this sample was used as the acceleration sensor package C. In the acceleration sensor package C, the upper cap and the lower cap are placed on the GND pad arranged in the sensor fixing portion, similarly to the acceleration sensor device according to the first embodiment of the present invention shown in FIG. Bumps and conductive paste are arranged, the GND pad and the upper cap are electrically connected, the upper cap is set to the GND potential, the upper cap and the lower cap are connected by the conductive paste, and the lower cap is set to the GND potential. . Ag paste was used as the conductive paste. The acceleration sensor device package C, like the acceleration sensor packages A and B, has a size of 3.5 mm × 3.5 mm and a thickness of 1 mm, and was mounted on a measurement printed board via lead-free solder. The acrylic resin plate charged by rubbing about 20 times on the non-woven fabric was brought close to the acceleration sensor package C to about 1 mm, and the maximum offset voltage was measured using the measurement pin arranged on the measurement printed board. As a result, the difference between the measured offset voltage of the acceleration sensor package C and the reference offset voltage of the acceleration sensor package A was 0.6 mV.

  Referring to the above measurement results, even if an electrostatically charged object comes close to the acceleration sensor package, the potential of the upper cap that covers the movable portion of the sensor, or the potential of the upper cap and the lower cap is set to GND, thereby moving the sensor. It can be seen that it is possible to reduce the movement of the portion by being pulled by the upper cap or the upper cap and the lower cap, and to improve the reliability of the apparatus.

100 Acceleration sensor device 102 Wiring board 104 IC
105 Sensor package 108 Upper cap 110 Lower cap 112 GND pad 114 Conductive paste

Claims (8)

A MEMS element having a fixed part and a movable part;
A first cap that covers the movable part at a predetermined interval and is fixed to the MEMS element by the fixed part;
A MEMS device comprising: a first ground pad electrically connected to the first cap by a conductive member, disposed on the fixed portion, and supplied with a ground potential.   2. The MEMS device according to claim 1, further comprising a second cap that is disposed at a predetermined interval from the movable portion and is fixed to the MEMS element on a side opposite to the fixing side of the first cap of the fixing portion.   The MEMS device according to claim 2, wherein the first cap and the second cap are electrically connected by a conductive member. An IC including a second ground pad to which a ground potential is supplied;
The second cap is disposed on the IC;
The MEMS device according to claim 2, wherein the second cap is electrically connected to the second ground pad through a conductive member.   The MEMS device according to claim 2, further comprising a second ground pad that is electrically connected to the second cap by a conductive member, is disposed on the fixed portion, and is supplied with a ground potential. A MEMS element having a fixed part and a movable part;
An IC that covers the movable part at a predetermined interval and is fixed to the MEMS element on the fixed part;
A MEMS device comprising: a first ground pad electrically connected to the IC by a conductive member, disposed on the fixed portion, and supplied with a ground potential. A substrate having a first ground pad to which a ground potential is supplied;
A MEMS element disposed on the substrate and having a fixed part and a movable part;
A MEMS device comprising: an IC that covers the movable part at a predetermined interval, is fixed to the MEMS element on the fixed part, and is electrically connected to the first ground pad by a conductive member. A substrate,
A sealing cap fixed to the substrate and forming a hollow space with the substrate;
An IC and a MEMS element disposed in the hollow space,
A MEMS device, wherein a conductive film is disposed on at least one of the inside and the outside of the sealing cap.

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