JP2006067552A - Piezoelectric oscillator, manufacturing method therefor and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator which prevents interference caused by electromagnetic waves, a manufacturing method therefor, and electronic equipment with the piezoelectric oscillator packaged therein. <P>SOLUTION: A piezoelectric oscillator 10 includes: a piezoelectric oscillation piece disposed in the vertical direction of a substrate; a circuit for oscillating the piezoelectric oscillation piece; a plurality of packaging terminals 20 which are provided on the substrate, in which one packaging terminal is formed as a ground electrode and which are electrically connected with a pad 26 provided in the circuit; an insulating material 30 sealing the circuit at least; and a conductor layer 32 which is provided at a position corresponding to an active face of the circuit at least on the surface of the insulating material 32, and electrically connected to the pad 26 electrically connected to the packaging terminal 20 as the ground electrode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a piezoelectric oscillator, a piezoelectric oscillator, and an electronic device, and more particularly, to a method for manufacturing a piezoelectric oscillator that prevents interference caused by electromagnetic waves and the influence of an ambient electric field, a piezoelectric oscillator, and an electronic device.

  A piezoelectric oscillator is mounted on an electronic device as a reference signal source or a reference frequency source of the electronic device. The piezoelectric oscillator has a configuration in which, for example, a semiconductor element is mounted on a die pad formed from a lead frame, and a lead terminal formed from the lead frame is provided in parallel with the semiconductor element, and is on one end of the lead terminal. A crystal resonator is bonded to the other end, the other end of the lead terminal and the semiconductor element are electrically connected by a wire, and the periphery of the semiconductor element and the crystal resonator is sealed with resin (for example, a patent) Reference 1).

  The piezoelectric oscillator is mounted with a piezoelectric vibrating piece and a circuit for oscillating the piezoelectric vibrating piece in a package base having a recess, and these are electrically connected, and the upper surface of the package base is sealed with a lid. There are things with different configurations.

Furthermore, in order to obtain a shielding effect, the piezoelectric oscillator includes a piezoelectric vibrator and a circuit component that are mounted on the printed board and a part of the ground plane on the upper surface of the piezoelectric vibrator is removed. There is a structure in which the upper space is covered and integrated with an insulating resin, and a conductive film is formed on the surface of the insulating resin and an exposed ground surface (see Patent Document 2).
JP-A-8-237032 JP 2003-243934 A

  By the way, when an electronic device equipped with a piezoelectric oscillator operates, an electromagnetic wave serving as noise may be radiated from a circuit around the piezoelectric oscillator. In particular, the higher the frequency used by electronic equipment, the easier it is to radiate electromagnetic waves. At this time, since the piezoelectric oscillator is not provided with a shield for shielding electromagnetic waves, there has been a problem in that the signal of the circuit mounted in the piezoelectric oscillator interferes with the electromagnetic waves. When this interference occurs, an unnecessary power spectrum is generated in the output signal power spectrum of the piezoelectric oscillator. Further, when an electric field is applied to the piezoelectric oscillator from the surroundings, the oscillation frequency of the piezoelectric oscillator may be shifted.

  In the case of Patent Document 2, since the piezoelectric vibrators and circuit components are arranged in the plane direction on the printed circuit board, a circuit pattern (wiring) for conducting the piezoelectric vibrators and circuit parts is required on the printed circuit board. Furthermore, since a circuit pattern that conducts to the metal lid of the piezoelectric vibrator is also required, the plane size of the piezoelectric oscillator cannot be reduced.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a method for manufacturing a piezoelectric oscillator and a piezoelectric oscillator that prevent interference due to electromagnetic waves.
It is another object of the present invention to provide an electronic device equipped with a piezoelectric oscillator that prevents interference caused by electromagnetic waves and the influence of surrounding electric fields.

  In order to achieve the above object, a piezoelectric oscillator manufacturing method according to the present invention includes a piezoelectric vibrating piece and a circuit that oscillates the piezoelectric vibrating piece arranged in a vertical direction of the substrate, and the piezoelectric vibrating piece, the circuit, and Electrically connecting, via a conductive member, a mounting terminal provided on the substrate, at least one of which is a ground electrode and joined to the mounting substrate, and a pad provided on the circuit Exposing a part of the conductive member electrically connected to the mounting terminal to be the ground electrode from an insulating material, sealing at least the circuit with the insulating material, and exposing the step Forming a conductive layer electrically connected to the conductive member on the surface of the insulating material.

  Since the piezoelectric vibrating piece and the circuit are arranged in the vertical direction, the plane size of the piezoelectric oscillator can be reduced. Further, since the conductive member exposed from the insulating material is electrically connected to the conductor layer, the conductor layer can be grounded, and an electromagnetic wave or an electric field incident on the circuit can be shielded by the conductor layer. Therefore, the oscillation frequency of the piezoelectric oscillator can be kept constant, and a good power spectrum can be obtained.

  The step of sealing the circuit with the insulating material is performed by bringing the inner surface of the mold covering the circuit into contact with the conductive member that is exposed from the insulating material and injecting the insulating material into the mold. It is characterized by that. Thus, when the circuit is covered with a mold, the mold and the conductive member are in contact with each other, so that even if an insulating material is injected into the mold, the conductive member can be exposed on the surface of the insulating material.

  The conductive member is a bump bonding material or a lead. Thereby, the said conductor layer and the pad provided in the said circuit can be electrically connected. In particular, if the conductive member is a bump bonding material, the plane area secured for the conductive member can be made substantially the pad area of the circuit, so that the plane size of the piezoelectric oscillator can be reduced. If the conductive member is a lead, a wide connection region between the conductive layer and the conductive member can be secured, and the conductive layer can be reliably grounded.

  The conductive member is a wire, and the step of sealing the circuit with the insulating material is performed by bringing the inner surface of the mold covering the circuit into contact with the wire that is exposed from the insulating material, It is characterized in that the height of the wire in contact with the mold is lowered by lowering the height, and then the insulating material is injected into the mold. Thereby, the height direction of the piezoelectric oscillator can be reduced in size. In addition, since the wire can be reliably exposed over a large area on the surface of the insulating material, conduction between the conductor layer and the wire can be ensured. Furthermore, since the conductive member can be formed in the wire bonding formation process of the circuit, the formation process is simple and the production cost can be reduced.

  Also, a step of arranging a piezoelectric vibrating piece and a circuit for oscillating the piezoelectric vibrating piece in the vertical direction of the substrate and electrically connecting them together, provided on the substrate, at least one of which is a ground electrode as a mounting substrate A step of electrically connecting a plurality of mounting terminals joined to the circuit and a pad provided in the circuit; and at least the pad electrically connected to the mounting terminal serving as the ground electrode is exposed. A step of sealing the circuit with an insulating material; and a step of forming a conductor layer on the surface of the insulating material and electrically connecting the exposed pad. In this case, the conductive member is an electrode film.

  Since the piezoelectric vibrating piece and the circuit are arranged in the vertical direction, the plane size of the piezoelectric oscillator can be reduced. Further, since the hole is formed in the insulating material and the conductive member is formed on the side surface, the ground electrode and the conductive layer can be conducted through the pad and the conductive member provided in the circuit. Therefore, since the electromagnetic wave or electric field incident on the circuit can be shielded by the conductor layer, the oscillation frequency of the piezoelectric oscillator can be kept constant and a good power spectrum can be obtained.

A piezoelectric oscillator according to the present invention includes a piezoelectric vibrating piece disposed in a vertical direction of a substrate, a circuit that oscillates the piezoelectric vibrating piece, and provided on the substrate, at least one of which is a ground electrode, and is provided in the circuit. A plurality of mounting terminals electrically connected to the pads, an insulating material sealing at least the circuit, and a surface of the insulating material provided at a position corresponding to at least an active surface of the circuit, and the ground electrode And a conductor layer electrically connected to the pad electrically connected to the mounting terminal. Even if an electromagnetic wave or an electric field is generated outside the piezoelectric oscillator, the electromagnetic wave or the electric field can be shielded by the conductor layer, and the piezoelectric oscillator can be prevented from interference by the electromagnetic wave or the electric field. Therefore, the oscillation frequency of the piezoelectric oscillator can be kept constant, and a good power spectrum can be obtained. Further, since the piezoelectric vibrating piece and the circuit are arranged in the vertical direction, the plane size of the piezoelectric oscillator can be reduced.
In addition, the insulating material is formed by tilting the side surfaces thereof to form a trapezoidal shape in side view. Thereby, the upper part of a piezoelectric oscillator can be made small.

  Also, a piezoelectric vibrating piece disposed in the vertical direction, a circuit for oscillating the piezoelectric vibrating piece, a plurality of leads formed from a lead frame and electrically connected to the circuit, and an insulating material sealing at least the circuit A mounting terminal formed by bending a lead protruding from the insulating material, a conductor layer formed at a position corresponding to at least an active surface of the circuit of the insulating material, and the lead frame, and the circuit, A conductive lead electrically connected to the conductor layer and electrically connected to the conductor layer via the circuit, the lead on which the mounting terminal serving as a ground electrode is formed; It is a feature. That is, the ground electrode and the conductor layer are electrically connected. Since the conductor layer is provided on the surface of the insulating material at least on the side overlapping with the active surface of the circuit, it is possible to prevent electromagnetic waves or electric fields from entering the circuit. Therefore, even if an electromagnetic wave or an electric field is generated outside the piezoelectric oscillator, the electromagnetic wave or the electric field can be shielded by the conductor layer, and the piezoelectric oscillator can be prevented from interference due to the electromagnetic wave or the electric field.

  In addition, the piezoelectric vibrating piece and the circuit are joined to each other with a lead interposed therebetween, and a hook-shaped lid body having a recessed portion inside is covered with the piezoelectric vibrating piece. The signal flowing between the piezoelectric vibrating piece and the circuit is not subject to interference by electromagnetic waves. Further, the parasitic capacitance due to the electric field does not change with respect to the lead to which the piezoelectric vibrating piece and the circuit are connected. Therefore, a highly reliable piezoelectric oscillator can be obtained.

  An electronic apparatus according to the present invention is characterized by mounting the above-described piezoelectric oscillator. Thereby, a highly reliable electronic device can be obtained.

  Hereinafter, preferred embodiments of a method for manufacturing a piezoelectric oscillator, a piezoelectric oscillator, and an electronic device according to the present invention will be described. First, the first embodiment will be described. FIG. 1 is a schematic explanatory diagram of the piezoelectric oscillator according to the first embodiment. FIG. 1A shows a form using a wire for the conductive member, and FIG. 1B shows a form using a bump bonding material for the conductive member. The piezoelectric oscillator 10 according to the first embodiment has a substrate 12 on the bottom surface. A plurality of mounting terminals 20 to be joined to the mounting substrate are formed on the lower surface of the substrate 12, and connection electrodes and circuit patterns (not shown) are formed on the upper surface. At least one of the mounting terminals 20 is a ground electrode. The ground electrode is used for grounding the piezoelectric oscillator 10 when the piezoelectric oscillator 10 is mounted on the mounting substrate. The connection electrode and the circuit pattern are electrically connected to the mounting terminal 20. A piezoelectric vibrator 14 is bonded to the upper surface of the substrate 12. The piezoelectric vibrator 14 has a configuration in which a piezoelectric vibrating piece (not shown) is mounted in a package base 16 and a lid 18 is joined to the upper part of the package base 16 to hermetically seal the inside. The piezoelectric vibrating piece may be a piezoelectric vibrating piece such as an AT cut, a tuning fork type piezoelectric vibrating piece, a surface acoustic wave resonance piece, or the like. An external terminal 22 that is electrically connected to the piezoelectric vibrating piece is provided on the back surface of the piezoelectric vibrator 14. The lid 18 and the substrate 12 are joined, and the piezoelectric vibrator 14 is mounted on the substrate 12.

  A circuit that oscillates the piezoelectric vibrating piece (piezoelectric vibrator 14) is bonded to the back surface of the piezoelectric vibrator 14. This circuit is formed as an integrated circuit (IC) chip, and a pad 26 to which wire bonding is applied is formed on one surface of the IC chip 24. The surface (back surface) opposite to the active surface on which the pad 26 is formed is bonded to the piezoelectric vibrator 14. At this time, the active surface of the IC chip 24 and the external terminal 22 of the piezoelectric vibrator 14 are oriented in the same direction. Note that a temperature compensation circuit, a voltage compensation circuit, or the like can be added to the IC chip 24. The pads 26 of the IC chip 24 and the external terminals 22 of the piezoelectric vibrator 14, and the pads 26 of the IC chip 24 and the connection electrodes formed on the substrate 12 are wire-bonded, so The vibrator 14, the IC chip 24, and the substrate 12 are electrically connected. In the electrical connection between the IC chip 24 and the substrate 12, at least one connection is conducted with the ground electrode and the IC chip 24, and the wire 28a for conducting them is higher than the height of the other wires 28b. It has been subjected.

  Wire bonding is usually performed in the steps described below. FIG. 2 is an explanatory diagram of wire bonding. As shown in FIG. 2A, first, the tip of the wire 28 is joined to the first pad 27 using a wire bonder, and then the wire 28 is pulled upward by a predetermined amount as shown by an arrow A in FIG. increase. This pull-up amount is set in advance in the wire bonder. Next, as shown by an arrow B in FIG. 2B, the wire 28 is pulled out sideways toward the second pad 29 provided on the side, and the wire 28 is joined to the second pad 29 with a wire bonder. Cut excess wire. Therefore, when the first pad 27 is higher than the second pad 29, for example, the first pad 27 is the pad 26 provided on the IC chip 24, and the second pad 29 is provided on the substrate 12. In the case of the connection electrode, when the forward bonding is performed by dropping from the first pad 27 to the second pad 29, the second pad 29 is separated from the IC chip 24 in order to prevent the wire 28 from contacting the IC chip 24. It is necessary to provide a high pulling amount after bonding the wire 28 to the first pad 27.

  However, as shown in FIG. 2C, when reverse bonding is performed from the second pad 29 to the first pad 27, the loop height of the wire 28 can be made lower than in the forward bonding, and the second pad 29 And the first pad 27 can be shortened. Therefore, in the first embodiment, it is preferable to perform reverse bonding on the connection electrode provided on the substrate 12 and the pad 26 provided on the IC chip 24. Thereby, the piezoelectric oscillator 10 can be reduced in size in the height direction and the plane direction.

  As shown in FIG. 1, the periphery of the piezoelectric vibrator 14 and the IC chip 24 is sealed with an insulating material 30. For the insulating material 30, for example, a resin such as epoxy can be used. At this time, the piezoelectric vibrator 14 and the IC chip 24 are sealed so that the wire 28a for conducting the IC chip 24 and the ground electrode is exposed on the upper surface of the insulating material 30. The sealing with the insulating material 30 may be performed as follows, for example. That is, the piezoelectric vibrator 14 and the IC chip 24 bonded to the substrate 12 and wire-bonded may be placed in a mold, and resin may be injected into the mold. At this time, the mold may have a height at which the upper surface of the mold contacts with the wire 28a for conducting the IC chip 24 and the ground electrode. When sealing with resin, the wire 28a for conducting the IC chip 24 and the ground electrode may not be exposed on the surface of the resin. In this case, the resin above the wire 28a is removed by photoetching or laser light. And the wire 28a may be exposed on the resin surface. Although only the wire 28a is higher than the other wires 28b and exposed on the resin surface, the height of the wire 28a is the same as that of the other wires 28b, and only the wire 28a is in contact with the upper surface of the mold. It may be formed by providing protrusions.

  Then, the conductor layer 32 is formed on the upper surface of the insulating material 30 while being electrically connected to the wire 28a for conducting the IC chip 24 and the ground electrode. The conductor layer 32 only needs to be formed of a conductive material, and may be formed using, for example, plating or a film forming method such as vapor deposition or sputtering. The conductor layer 32 may be made of a material having excellent adhesion with the insulating material 30. Further, a material that adheres well to the insulating material 30 and a material excellent in oxidation resistance or corrosion resistance may be used. For example, the conductor layer 32 may have a one-layer structure made of a material having good adhesion to the insulating material 30, or a two-layer structure in which a material having good oxidation resistance or corrosion resistance is provided on a material having good adhesion to the insulating material 30. It is good. As a result, the conductor layer 32 is electrically connected to the ground electrode via the conductive member (wire 28a). The conductor layer 32 may be provided at least at a location overlapping with the active surface of the IC chip 24. Further, when the conductor layer 32 is provided at a position overlapping the external terminal 22 of the piezoelectric vibrator 14, it is possible to prevent interference of electromagnetic waves on the piezoelectric vibrator 14 or an electric field generated from the outside. Further, the conductor layer 32 may be provided on the upper surface and side surfaces of the insulating material 30.

  In this way, the piezoelectric oscillator 10 forms the conductor layer 32 corresponding to the active surface of the IC chip 24 provided therein, and the conductor layer 32 is electrically connected to the ground electrode. The interference of the electric field generated from can be prevented. That is, when the piezoelectric oscillator 10 is mounted on a mounting board mounted on an electronic device and the ground electrode of the piezoelectric oscillator 10 is grounded to the electronic device, the conductor layer 32 is grounded to the electronic device. Therefore, even when electromagnetic waves that become noise are emitted from an electronic component or the like mounted around the piezoelectric oscillator 10 or an electric field is generated, the grounded conductor layer 32 prevents the interference of the electromagnetic waves or the electric field, and the oscillation frequency of the piezoelectric oscillator 10 is increased. It can be kept constant, and a good power spectrum of the output signal can be obtained.

  In the embodiment described above, the step of sealing the piezoelectric vibrator 14 and the IC chip 24 with the insulating material 30 has been described as a step of sealing while exposing a part of the wire 28 from the insulating material 30. Such a process may be used. That is, after the piezoelectric vibrator 14, the IC chip 24, and the wire 28 are sealed with the insulating material 30, the insulating material 30 above the wire 28 is removed, and the wire 28 is exposed from the insulating material 30. . Further, the step of sealing the piezoelectric vibrator 14 and the IC chip 24 with the insulating material 30 is performed by bringing the wire 28a serving as a conductive member into contact with the inner surface of the mold that covers the IC chip 24 and then contacting the wire 28a. It may be a step of lowering the height of the mold to lower the height of the wire 28a and then injecting the insulating material 30 into the mold. Thus, as the mold height decreases, the contact area between the apex of the wire 28a and the mold increases, so that the wire 28a is exposed from the insulating material 30 when sealed by the insulating material 30. The area to be increased. Therefore, in such a process, the wire 28a can be reliably exposed on the surface of the insulating material 30, and can be exposed in a wide area.

  In the embodiment described above, the wire 28 is used as the conductive member for electrically connecting the IC chip 24 and the conductor layer 32 as shown in FIG. 1A. However, FIG. As shown in the figure, the bump bonding material 34 may be used as the conductive member. In this case, the pad 26 of the IC chip 24 to which the bump bonding material 34 is bonded may be electrically connected to the ground electrode formed on the substrate 12. Further, as in the modification of the piezoelectric oscillator according to the first embodiment shown in FIG. 3, a hole 36 is provided above the pad 26 of the IC chip 24 for conducting the IC chip 24 and the conductor layer 32. The electrode film 38 may be formed on the side surface of the portion 36 and the portion of the pad 26 exposed from the insulating material 30 to make the pad 26 and the conductor layer 32 conductive. The hole 36 may be formed by providing a protrusion on a mold used to seal the periphery of the piezoelectric vibrator 14 and the IC chip 24 with the insulating material 30. It may be formed by sealing the periphery with the insulating material 30 and then performing an etching process or irradiating laser light. Alternatively, the hole 36 may be filled with a conductive material, and the pad 26 of the IC chip 24 and the conductor layer 32 may be conducted through this conductive material. The conductive member may be any means as long as it can electrically connect the pad 26 of the IC chip 24 and the conductor layer 32.

  In the embodiment described above, the substrate 12 is provided on the bottom surface of the piezoelectric oscillator 10, but a lead frame may be used instead of the substrate 12. Specifically, the piezoelectric oscillator includes a plurality of mounting terminals formed of a lead frame, and at least one of the mounting terminals is used as a ground electrode, and the mounting terminal, the piezoelectric vibrator, and the IC chip are electrically connected by wires. Wire that becomes a conductor layer and a conductive member by sealing the periphery of the piezoelectric vibrator, IC chip and wire with an insulating material and forming a conductor layer on the surface of the insulating material corresponding to at least the side overlapping the IC chip And the lead frame protruding from the insulating material may be cut and formed.

  Next, a second embodiment will be described. In the second embodiment, the same components as those of the piezoelectric oscillator according to the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified. FIG. 4 is a schematic explanatory diagram of the piezoelectric oscillator according to the second embodiment. FIG. 4A is a plan view of the piezoelectric oscillator in which the conductor layer and the insulating material are omitted, and FIG. 4B is a cross-sectional view taken along line AA in FIG. The piezoelectric oscillator 40 according to the second embodiment has a piezoelectric vibrator 14. An external terminal (not shown) is provided on the back surface of the piezoelectric vibrator 14, and the lower surface of the connection terminal 42 formed from a lead frame and the external terminal are electrically and mechanically connected. Further, the back surface of the IC chip 24 is bonded to the back surface of the piezoelectric vibrator 14, and wire bonding is applied to the pads 26 provided on the active surface of the IC chip 24 and the upper surface of the connection terminal 42, thereby the IC chip 24 and the piezoelectric vibrator. 14 (piezoelectric vibrating piece) is electrically connected. One end of a mounting terminal forming lead 44 formed from the lead frame extends in the vicinity of the IC chip 24, and wire bonding is applied to the pad 26 of the IC chip 24 and the mounting terminal forming lead 44.

  The piezoelectric oscillator 40 has a conductive member (conductive lead) 48 formed from a lead frame. One end of the conductive member 48 is extended in the vicinity of the IC chip 24, and wire bonding is applied to the one end and the pad 26 of the IC chip 24 to be electrically connected. Further, the other end side is formed to rise toward the pad 26 side (upward) of the IC chip 24. The conductive member 48 is formed higher than the highest position of the wire 50 applied to the IC chip 24, the conductive member 48, the connection terminal 42, and the mounting terminal forming lead 44. The conductive member 48 is electrically connected to a ground electrode (not shown). The conductive member 48 is independent of the mounting terminal forming lead 44, but may be integrated with the lead serving as the internal ground electrode of the mounting terminal forming lead 44.

  The periphery of the piezoelectric vibrator 14 and the IC chip 24 is sealed with an insulating material 30. At this time, the piezoelectric vibrator 14 and the IC chip 24 are arranged such that the other end of the conductive member 48 is exposed on the surface of the insulating material 30 and the other end side of the mounting terminal forming lead 44 protrudes from the insulating material 30. Sealed. What is necessary is just to perform sealing by this insulating material 30 similarly to 1st Embodiment. Thereafter, the conductor layer 32 is formed on the surface of the insulating material 30 while being electrically connected to the conductive member 48. The conductor layer 32 may be formed on the surface of the insulating material 30 on the IC chip 24 side as shown in FIG. 4, but may be formed on at least the upper surface of the IC chip 24, and the upper surface of the IC chip 24 and the piezoelectric layer It may be formed on the upper surface of the vibrator 14 with the external terminal. The conductor layer 32 is a part of the mounting terminal forming lead 44 not electrically connected to the ground electrode, or the surface and side surfaces of the insulating material 30 on the IC chip 24 side so as not to be electrically connected to the connection terminal 42. It may be formed on all surfaces of the insulating material 30.

  Further, the process of sealing the piezoelectric vibrator 14 and the IC chip 24 with the insulating material 30 may be the following process in addition to the process described above. In other words, after the other end of the conductive member 48 is sealed with the insulating material 30 together with the piezoelectric vibrator 14 and the IC chip 24, the insulating material 30 above the conductive member 48 is removed by etching or laser light irradiation. The other end of the insulating material 30 may be exposed from the insulating material 30.

  Thereafter, the other end of the mounting terminal forming lead 44 protruding from the insulating material 30 is bent below the insulating material 30 on the piezoelectric vibrator 14 side, and the mounting terminal 46 is formed at the other end.

  As described above, the piezoelectric oscillator 40 has the conductor layer 32 formed above the pad 26 (active surface) of the IC chip 24 provided therein, and the conductor layer 32 is electrically connected to the ground electrode. The interference of electromagnetic waves or external electric fields can be prevented. That is, when the piezoelectric oscillator 40 is mounted on a mounting board mounted on an electronic device and the ground electrode of the piezoelectric oscillator 40 is grounded to the electronic device, the conductor layer 32 is grounded to the electronic device. Therefore, even if electromagnetic waves that become noise or an electric field from the outside are generated from an electronic component or the like mounted around the piezoelectric oscillator 40, the grounded conductor layer 32 prevents the electromagnetic wave or the electric field from interfering with each other. The oscillation frequency can be kept constant and a good power spectrum can be obtained.

  When the piezoelectric oscillator 40 is mounted on a mounting board, the circuit pattern may pass below the piezoelectric oscillator 40 depending on the circuit pattern configuration of the mounting board. However, interference of electromagnetic waves or electric fields is prevented above the circuit pattern. Since the shield, that is, the conductor layer 32 is provided, interference into the piezoelectric oscillator 40 can be reduced by an electromagnetic wave or an electric field generated from the circuit pattern.

  In the above-described embodiment, the conductive member 48 is described as being configured from a lead frame. However, the conductive member 48 may be the conductive member such as the wire or the bump bonding material described in the first embodiment. That is, the conductive member 48 may be any means that can electrically connect the IC chip 24 and the conductor layer 32. In addition, the back surface of the piezoelectric vibrator 14 and the back surface of the IC chip 24 have been described. However, the back surface of the piezoelectric vibrator 14 and the back surface of the IC chip 24 are bonded through a die pad formed from a lead frame. It may be. In addition, the conductive member, the connection terminal, and the mounting terminal forming lead can be formed not only from one lead frame but also from two or more lead frames. Alternatively, the mounting terminal forming lead 44 may be bent toward the IC chip 24 to form the mounting terminal 46 below the IC chip 24.

  In the piezoelectric oscillator 40, one end of an adjustment terminal formed from a lead frame is extended in the vicinity of the IC chip 24, and wire bonding is applied to the adjustment terminal and the pad 26 of the IC chip 24 to adjust the adjustment terminal and the IC chip. 24 may be electrically connected. The adjustment terminal is used when writing a program to the IC chip 24, and is used for characteristic inspection and characteristic adjustment of electronic components. Here, the characteristic inspection means an operation check of the IC chip 24 after the piezoelectric oscillator 40 is formed, a characteristic inspection for the piezoelectric oscillator 40, and the like. The characteristic adjustment means that when a temperature compensation circuit is added to the IC chip 24, a function of correcting the frequency change due to the temperature of the piezoelectric oscillator 40 or a function of changing the frequency by the input voltage is added to the IC chip 24. In addition, it means adjusting the change sensitivity.

  In the above-described embodiment, the piezoelectric vibrator 14 is mounted on the piezoelectric oscillator. However, a piezoelectric vibrating piece may be mounted. FIG. 5 shows a modification of the piezoelectric oscillator according to the second embodiment. FIG. 5A is a plan view of the piezoelectric oscillator in which the description of the conductor layer and the insulating material is omitted, and FIG. 5B is a cross-sectional view taken along the line BB in FIG. ) Is a bottom view of the piezoelectric oscillator in which the description of the lid and the mounting terminal is omitted. The piezoelectric oscillator according to this modification has a die pad 52 formed from a lead frame. The IC chip 24 is bonded to the upper surface of the die pad 52. Around the die pad 52, a connection terminal 42 formed from a lead frame and mounting the piezoelectric vibrating piece 54 on the lower surface and one end of a mounting terminal forming lead 44 are extended. Further, one end of the conductive member 48 formed from the lead frame is extended in the vicinity of the die pad 52, and the other end side is raised toward the active surface side of the IC chip 24. The upper side of the lead frame, that is, the periphery of the IC chip 24 is sealed with an insulating material 30. At this time, the other end of the conductive member 48 is exposed on the surface of the insulating material 30 and the periphery of the IC chip 24 is sealed. A conductor layer 32 is formed on the upper surface of the insulating material 30 while being electrically connected to the conductive member 48.

  The piezoelectric vibrating piece 54 is mounted on the lower surface of the insulating material 30. At this time, the piezoelectric vibrating piece 54 and the IC chip 24 are joined with the lead interposed therebetween. Specifically, the terminal 56 of the piezoelectric vibrating piece 54 and the lower surface of the connection terminal 42 are electrically and mechanically connected via the conductive bonding material 58. Therefore, the piezoelectric vibrating piece 54 and the IC chip 24 are electrically connected via the connection terminal 42 and the wire 50. A lid 60 is bonded to the lower surface of the insulating material 30 on which the piezoelectric vibrating piece 54 is mounted, and the piezoelectric vibrating piece 54 is hermetically sealed. The lid 60 has a bowl shape formed by raising the side edge of the flat substrate, and is joined to the lower surface of the insulating material 30 so that the piezoelectric vibrating piece 54 is disposed in the recess.

Thereafter, the mounting terminal forming lead 44 provided on the lower surface of the insulating material 30 and projecting sideways is bent below the lid body 60 that hermetically seals the piezoelectric vibrating piece 54 to form the mounting terminal forming lead 44. A mounting terminal 46 is formed at the other end.
Even in such a modification, the same effects as those of the above-described embodiment can be obtained.

  Next, a third embodiment will be described. In the third embodiment, parts having the same configuration as those of the piezoelectric oscillators according to the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted or simplified. FIG. 6 is a schematic explanatory diagram of the piezoelectric oscillator according to the third embodiment. A piezoelectric oscillator 70 according to the third embodiment has a package base 72 composed of a planar substrate and side portions formed by raising the periphery of the substrate upward and downward. That is, the package base 72 is configured to include the recessed portions 74 and 82 at the upper and lower portions. A mount electrode 76 is formed on the bottom surface of the upper recessed portion 74 of the package base 72, and the piezoelectric vibrating piece 54 is mounted on the mount electrode 76 via a conductive bonding material 58. The lid body 78 is bonded to the upper surface of the side portion 80 raised upward from the flat substrate, and hermetically seals the upper recessed portion 74.

  Further, the back surface of the IC chip 24 is joined to the lower recessed portion 82 of the package base 72. Then, wire bonding is applied to the pad 26 of the IC chip 24 and the connection electrode 84 formed in the lower recessed portion 82. A part of the connection electrode 84 formed in the lower recess 82 is electrically connected to the mount electrode 76. Therefore, the IC chip 24 and the piezoelectric vibrating piece 54 are electrically connected. A plurality of mounting terminals 88 to be bonded to the mounting substrate are provided on the back surface of the package base. At least one of the mounting terminals 88 is a ground electrode. In the electrical connection between the IC chip 24 and the connection electrode 84 formed in the lower recessed portion 82, at least one connection is electrically connected to the ground electrode. At this time, the wire 86a that is electrically connected to the ground electrode is provided so as to be higher than the height of the other wire 86b.

  The insulating material 30 is injected into the lower concave portion 82 to seal the periphery of the IC chip 24. At this time, the IC chip 24 is sealed so that the wire 86 a that conducts the IC chip 24 and the ground electrode is exposed on the surface of the insulating material 30. A wire 86a for conducting the IC chip 24 and the ground electrode is a conductive member. The conductor layer 32 is formed on the surface of the insulating material 30 while being electrically connected to the conductive member (wire 86a). The conductor layer 32 may be formed on the surface of the insulating material 30 that overlaps at least the IC chip 24.

  In this way, the piezoelectric oscillator 70 has the conductor layer 32 formed on the surface of the insulating material 30 corresponding to the position overlapping the IC chip 24, and the conductor layer 32 is electrically connected to the ground electrode. The interference of the electric field can be prevented. That is, when the piezoelectric oscillator 70 is mounted on a mounting board mounted on an electronic device and the ground electrode of the piezoelectric oscillator 70 is grounded to the electronic device, the conductor layer 32 is grounded to the electronic device. Therefore, even if an electromagnetic wave that becomes noise or an external electric field is generated from an electronic component or the like mounted around the piezoelectric oscillator 70, the grounded conductor layer 32 prevents the electromagnetic wave or the electric field from interfering with each other. The oscillation frequency can be kept constant and a good power spectrum can be obtained.

  When the piezoelectric oscillator 70 is mounted on a mounting board, the circuit pattern may pass below the piezoelectric oscillator 70 depending on the circuit pattern configuration of the mounting board. However, interference of electromagnetic waves or electric fields is prevented above the circuit pattern. Since the shield, that is, the conductor layer 32 is provided, no interference occurs in the piezoelectric oscillator 70 by the electromagnetic wave or electric field generated from the circuit pattern.

  The process of sealing the IC chip 24 with the insulating material 30 may be a process described below. In other words, the periphery of the IC chip 24 and the conductive member may be sealed with the insulating material 30, and then the insulating material 30 above the conductive member may be removed to expose the conductive member from the insulating material 30. The conductive member is not limited to the form used for the wire, and any means can be used as long as it can electrically connect the IC chip 24 and the conductor layer 32.

  Next, a fourth embodiment will be described. In the fourth embodiment, parts having the same configurations as those of the piezoelectric oscillators according to the first to third embodiments are denoted by the same reference numerals, and description thereof is omitted or simplified. FIG. 7 shows a schematic sectional view of a piezoelectric oscillator according to the fourth embodiment. A piezoelectric oscillator 100 according to the fourth embodiment includes a piezoelectric vibrator 14. The piezoelectric vibrator 14 has a package base 108 having a recessed portion 106, and a mount electrode 76 is provided inside the recessed portion 106. A piezoelectric vibrating piece 54 is mounted on the mount electrode 76 via a conductive bonding material 58. The lid 110 is joined to the opening of the recessed portion 106, and the piezoelectric vibrating piece 54 is hermetically sealed. Such a piezoelectric vibrator 14 is disposed with the recessed portion 106 facing downward.

  A plurality of connection electrodes 102 are provided on one surface of the piezoelectric vibrator 14, that is, in the case shown in FIG. Further, a plurality of mounting terminals 104 are provided on the other surface of the piezoelectric vibrator 14, that is, in the case shown in FIG. At least one of the mounting terminals 104 is a ground electrode 112. In addition, at least two of the plurality of connection electrodes 102 are electrically connected to the mount electrode 76, and the other is electrically connected to the mounting terminal 104. Of these connection electrodes 102, those that are electrically connected to the ground electrode 112 are ground pads 114.

  The IC chip 24 that oscillates the piezoelectric vibrator 14 is bonded to one surface of the piezoelectric vibrator 14, and the piezoelectric vibrating piece 54 and the IC chip 24 are arranged in the vertical direction. The IC chip 24 is electrically connected to each connection electrode 102 using wires 28 (28a, 28b). The wire 28a wire-bonded to the grounding pad 114 serves as a conductive member, and the apex thereof is arranged at a position higher than the other wires 28b. That is, the apex of the wire 28 a serving as a conductive member is arranged at a position higher than the upper surface of the IC chip 24.

  The periphery of the IC chip 24 is covered with an insulating material 30. That is, the periphery of the connection electrode 102, the IC chip 24, and the wire 28 provided on one surface of the piezoelectric vibrator 14 is sealed with the insulating material 30. Note that the apex of the wire 28 a serving as a conductive member is exposed on the surface of the insulating material 30. In addition, the side surface of the insulating material 30 is formed obliquely and has a trapezoidal shape when viewed from the side. A conductor layer 32 is provided on the surface of the insulating material 30, and the conductor layer 32 and a wire 28a serving as a conductive member are connected. Thereby, the ground electrode 112 and the conductor layer 32 are electrically connected via the conductive member and the ground pad 114.

  Next, a method for manufacturing the piezoelectric oscillator 100 according to the fourth embodiment will be described. FIG. 8 is an explanatory diagram of the manufacturing process of the piezoelectric oscillator according to the fourth embodiment. First, as shown in FIG. 8A, a package base sheet 116 in which a plurality of package bases 108 are connected in a planar direction is formed. In the package base sheet 116, a mount electrode 76 is formed in each recess 106, and a connection electrode 102 is formed on one surface (upper surface) of the package base 108, and mounted on the other surface (lower surface). A terminal 104 is formed.

  Next, as shown in FIG. 8B, the piezoelectric vibrating piece 54 is bonded onto the mount electrode 76 of each recessed portion 106 using the conductive bonding material 58. Thereafter, the lid 110 is joined to the opening of each recess 106. Thereby, each recess 106 is hermetically sealed. Next, as shown in FIG. 8C, the IC chip 24 is bonded to one surface of the package base sheet 116 corresponding to the position where each piezoelectric oscillator 100 is formed. Thereafter, wire bonding is applied to the IC chip 24 and the connection electrode 102, and the IC chip 24 and the connection electrode 102 are electrically connected by the wire 28. At this time, the wire 28a serving as the conductive member is applied so that the position of the apex is higher than that of the other wire 28b.

  Next, after the package base sheet 116 to which the IC chip 24 is bonded is placed in the mold, the insulating material 30 is injected into the mold, and the periphery of the IC chip 24, the connection electrode 102, and the wire 28 is shown in FIG. Seal as shown in d). At this time, the wire 28 a serving as the conductive member is in a state where the vicinity of the apex is exposed on the surface of the insulating material 30. Next, as shown in FIG. 8E, after the conductive layer 32 and the conductive member are made conductive by forming the conductive layer 32 on the surface of the insulating material 30, that is, above and on the side of the IC chip 24, Cut into individual piezoelectric oscillators 100.

According to the piezoelectric oscillator 100 according to the fourth embodiment as described above, the conductor layer 32 is provided above or on the side of the IC chip 24, and the conductor layer 32 is electrically connected to the ground electrode 112. The interference of the electric field can be prevented. That is, when the piezoelectric oscillator 100 is mounted on a mounting board mounted on the electronic device and the ground electrode 112 of the piezoelectric oscillator 100 is grounded to the electronic device, the conductor layer 32 is grounded to the electronic device. Therefore, even if an electromagnetic wave that becomes noise or an external electric field is generated from an electronic component or the like mounted around the piezoelectric oscillator 100, the electromagnetic wave or electric field that is incident from above or from the side by the grounded conductor layer 32. Therefore, the oscillation frequency of the piezoelectric oscillator 100 can be kept constant, and a good power spectrum can be obtained.
In addition, since the side surface of the insulating material 30 is formed obliquely and formed into a trapezoidal shape when viewed from the side, the upper portion of the piezoelectric oscillator 100 can be particularly small.

  In the fourth embodiment described above, the conductive member is a wire 28. However, as described in the first embodiment, the IC chip 24 and the conductor layer 32 are made conductive by using a bump bonding material. Alternatively, a hole may be formed in the insulating material 30 to form an electrode film on the side surface thereof, and the IC chip 24 and the conductor layer 32 may be conducted through the electrode film.

  Further, in the above-described fourth embodiment, the side surface of the insulating material 30 is formed obliquely and formed into a trapezoidal shape as viewed from the side, but is not limited to this mode. FIG. 9 shows a modification of the piezoelectric oscillator according to the fourth embodiment. The piezoelectric oscillator 100 can be configured such that the side surface of the insulating material 30 is formed along the vertical direction of the piezoelectric oscillator 100 and the conductor layer 32 is provided along this side surface. In order to form such a piezoelectric oscillator 100, as shown in FIG. 9, an insulating material 30 is provided on one surface of the package base sheet 116 except for a portion where the package base sheet 116 is cut, and then the insulating material is formed. The conductor layer 32 may be provided on the upper and side surfaces of the substrate 30 and the package base sheet 116 on which the insulating material 30 is not provided, and then the package base sheet 116 and the conductor layer 32 may be cut along the cut portions.

  The piezoelectric oscillators 10, 40, 70, 100 according to the first to fourth embodiments generate a clock signal for control by a piezoelectric oscillator, such as a digital cellular phone device, a personal computer, a workstation, or a portable information terminal. Can be mounted on the electronic equipment to obtain. As described above, by mounting the piezoelectric oscillators 10, 40, 70, and 100 according to the above-described embodiments on an electronic device, a highly reliable electronic device can be realized.

It is a schematic explanatory drawing of the piezoelectric oscillator which concerns on 1st Embodiment. It is explanatory drawing of wire bonding. It is a modification of the piezoelectric oscillator which concerns on 1st Embodiment. It is a schematic explanatory drawing of the piezoelectric oscillator which concerns on 2nd Embodiment. It is a modification of the piezoelectric oscillator which concerns on 2nd Embodiment. It is a schematic explanatory drawing of the piezoelectric oscillator which concerns on 3rd Embodiment. It is a schematic sectional drawing of the piezoelectric oscillator which concerns on 4th Embodiment. It is explanatory drawing of the manufacturing process of the piezoelectric oscillator which concerns on 4th Embodiment. It is a modification of the piezoelectric oscillator which concerns on 4th Embodiment.

Explanation of symbols

10 ......... Piezoelectric oscillator, 14 ......... Piezoelectric vibrator, 24 ......... IC chip, 30 ......... Insulating material, 32 ......... Conductive layer, 40 ......... Piezoelectric oscillator, 48 ......... Conductive member, 54... Piezoelectric vibrating piece, 70... Piezoelectric oscillator, 100.

Claims (12)

Disposing a piezoelectric vibrating piece and a circuit for oscillating the piezoelectric vibrating piece in a vertical direction of the substrate, and electrically connecting the piezoelectric vibrating piece and the circuit;
A step of electrically connecting via a conductive member a mounting terminal that is provided on the substrate and at least one of which is a ground electrode and is bonded to the mounting substrate, and a pad provided on the circuit;
Exposing a part of the conductive member electrically connected to the mounting terminal to be the ground electrode from an insulating material, and sealing at least the circuit with the insulating material;
Forming a conductive layer electrically connected to the exposed conductive member on the surface of the insulating material;
A method for manufacturing a piezoelectric oscillator, comprising:   The step of sealing the circuit with the insulating material is performed by bringing the inner surface of the mold covering the circuit into contact with the conductive member that is exposed from the insulating material and injecting the insulating material into the mold. The method for manufacturing a piezoelectric oscillator according to claim 1. The conductive member is a wire;
The step of sealing the circuit with the insulating material is performed by bringing the inner surface of the mold covering the circuit into contact with the wire exposing the insulating material, and then reducing the height of the mold. 2. The method of manufacturing a piezoelectric oscillator according to claim 1, wherein the height of the wire in contact with the wire is lowered, and then the insulating material is injected into the mold. Arranging the piezoelectric vibrating piece and a circuit for oscillating the piezoelectric vibrating piece in the vertical direction of the substrate, and electrically connecting them;
A step of electrically connecting a plurality of mounting terminals provided on the substrate, at least one of which is a ground electrode and bonded to the mounting substrate, and a pad provided on the circuit;
Sealing the circuit with an insulating material so that at least the pad electrically connected to the mounting terminal to be the ground electrode is exposed;
Forming a conductor layer on the surface of the insulating material and electrically connecting the exposed pad;
A method for manufacturing a piezoelectric oscillator, comprising:   5. The method of manufacturing a piezoelectric oscillator according to claim 1, wherein the piezoelectric vibrating piece is a piezoelectric vibrator housed in a package. A piezoelectric vibrating piece disposed in the vertical direction of the substrate and a circuit for oscillating the piezoelectric vibrating piece;
A plurality of mounting terminals provided on the substrate, at least one of which is a ground electrode, and electrically connected to pads provided in the circuit;
An insulating material that seals at least the circuit;
A conductor layer electrically connected to the pad, which is provided at a position corresponding to at least the active surface of the circuit on the surface of the insulating material and is electrically connected to the mounting terminal serving as the ground electrode;
A piezoelectric oscillator comprising: The piezoelectric vibrating piece is a piezoelectric vibrator housed in a package,
The insulating material seals the piezoelectric vibrator together with the circuit.
The piezoelectric oscillator according to claim 6.   The piezoelectric oscillator according to claim 6 or 7, wherein a side surface of the insulating material is inclined and formed into a trapezoidal shape in a side view. A piezoelectric vibrating piece disposed in the vertical direction and a circuit for oscillating the piezoelectric vibrating piece;
A plurality of leads formed from a lead frame and electrically connected to the circuit;
An insulating material that seals at least the circuit;
A mounting terminal provided by bending a lead protruding from the insulating material;
A conductor layer formed at a position corresponding to at least an active surface of the circuit of the insulating material;
The lead formed of the lead frame, electrically connecting the circuit and the conductor layer, and formed with the mounting terminal serving as a ground electrode, is electrically connected to the conductor layer via the circuit. Conductive leads to connect;
A piezoelectric oscillator comprising:   The piezoelectric oscillator according to claim 9, wherein the piezoelectric vibrating piece is housed in a package to form a piezoelectric vibrator, and the circuit is bonded to one surface of the piezoelectric vibrator.   10. The piezoelectric oscillator according to claim 9, wherein the piezoelectric vibrating piece and the circuit are joined to each other with a lead interposed therebetween, and a hook-shaped lid body having a recessed portion is covered on the piezoelectric vibrating piece. .   An electronic apparatus comprising the piezoelectric oscillator according to claim 6.

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