JP2014175791A - Surface-mounted crystal oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-mounted crystal oscillator improving reliability by avoiding a connection defect caused by direct conduction of high heat of reflow to packaging terminals of a ground along a grounding path of a metal cover and instability in solder fillet formation between the packaging terminals during packaging.SOLUTION: The surface-mounted crystal oscillator comprises: a metal cover 7 sealing a recess 12 in which a crystal vibrator 2 is accommodated, shielding the recess from an external electromagnetic field; and a plurality of packaging terminals 4a, 4b, 4c and 4d including a ground terminal 4b on a surface of a container body 1 opposite to the metal cover 7. An IC chip 3 includes two IC terminals 31c -1 and 31c-2 connected within the IC chip for grounding, and the one IC terminal 31c-1 is connected to the metal cover 7 through an inner layer conductor pattern 18b formed on a bottom wall of the container body 1 and a via hole 13b formed on a frame wall. The other IC terminal 31c-2 is connected to the packaging terminal 4b for grounding through a wiring pattern 16 formed on the bottom wall 1b of the container body 1 and a via hole 13b formed on the frame wall.

Description

  The present invention relates to a surface-mount crystal oscillator, and more particularly to a surface-mount crystal oscillator in which a crystal resonator and an IC chip that constitutes an oscillation circuit and the like together with the crystal resonator are housed in a common container body.

  A surface-mount crystal oscillator (hereinafter referred to as a surface-mount oscillator) is small and lightweight, and is built in as a reference source for frequency and time in portable electronic devices represented by, for example, mobile phones. In such a case, the container main body is formed in an H shape composed of recesses having two opposite cross sections, and the crystal resonator is accommodated in the recess on one main surface, and the IC chip is accommodated in the recess on the other main surface. There is a surface mount oscillator.

  In addition, only one recess is provided in the container body, and the crystal oscillator and the IC chip are arranged vertically in this recess, or the crystal oscillator and the IC chip are arranged side by side in one recess, etc. It has been known. The IC chip is integrated with an oscillation circuit and an output circuit that constitute an oscillator together with a crystal resonator, and a temperature compensation circuit and a temperature control circuit depending on the type of the oscillator.

  In any of the above-mentioned types of crystal oscillators, in order to avoid changing the oscillation frequency due to fluctuations in ambient conditions of external temperature and humidity, dust intrusion, etc., the crystal oscillator is also shielded from external electromagnetic waves. Therefore, after the crystal resonator and the IC chip are accommodated in the container body, at least the recessed space in which the crystal resonator is accommodated is sealed with a lid so as to be shielded from the external atmosphere.

  FIG. 3 is an explanatory diagram of a structural example of a conventional surface mount oscillator. The surface-mount oscillator 100 has a flat box shape with a substantially rectangular shape in plan view. 3A is a longitudinal sectional view of the container main body, FIG. 3B is a plan view of the concave portion in which the IC chip of the container main body is mounted as viewed from the direction of arrow A in FIG. The gold bumps 8 (8a, 8b, 8c, 8d, 8e, 8f) of the IC chip terminals (IC terminals) 31 (31a, 31b, 31c, 31d, 31e, 31f) are shown. And shown in a state of being connected to the electrode pad 17 provided in the wiring pattern provided on the bottom wall. Note that FIG. 3A corresponds to a cut surface taken along the line A-A ′ of FIG.

  The surface mount oscillator 100 is configured by accommodating a crystal resonator 2 and an IC chip 3 in a container body 1 formed by bottom walls 1a and 1b and frame walls 1c, 1d and 1e. The bottom walls 1a, 1b and the frame walls 1c, 1d, 1e are formed of an insulating substrate obtained by laminating and firing ceramic sheets (also referred to as green sheets). When laminating ceramic sheets, each layer has a required shape, and a required conductor layer pattern (inner layer conductor pattern) is provided on the outer surface or the inner surface of the interlayer, and is manufactured by a sintering process. The number of laminated ceramic sheets of the bottom wall and the frame wall is selected according to requirements such as the thickness of the ceramic sheet, Young's modulus, and the size of the surface mount oscillator. The structure shown here shows the number of layers, thickness, and the like for convenience of explanation, and is not essential to the present invention.

  In the container body 1 of the surface mount oscillator 100 shown in FIG. 3, the crystal resonator 2 is accommodated in the first recess 12 having the bottom wall 1a as the first bottom wall and the frame wall 1c as the first frame wall. Although not shown in the drawings, the crystal resonator 2 is a crystal resonator body in which a crystal piece (crystal blank) is sandwiched between two electrodes (excitation electrodes). Note that a unit in which such a crystal vibrating body 2 is accommodated in a container may be referred to as a crystal resonator. In the crystal resonator 2, the two excitation electrodes are electrically and mechanically fixed to the crystal terminal 11 provided on the bottom surface of the first recess 12 with the conductive adhesive 5.

  The IC chip 3 is housed in the second recess 13 having the bottom wall 1b as the second bottom wall and the frame walls 1d and 1e as the second frame walls. On the opening end surface of the second recess 13 (the upper surface of the frame wall 1e), a plurality of terminals (hereinafter also referred to as mounting terminals) 4 electrically connected to the IC chip 3 (here, four: 4a, 4a, 4b, 4c, 4d). The electrical connection between the IC chip 3 and the mounting terminal 4 is made through an interior conductor pattern 18a or the like provided in the ceramic sheet, the via hole 13a or the like (both are partially shown), or a notch provided on the side wall surface of the container body 1 ( This is done through a connection conductor (also not shown) formed in the castellation. The mounting terminal 4 is formed by baking a base electrode (a refractory metal such as tungsten: W or molybdenum: Mo) on the opening end face of the second recess 13 and then metallizing it, and then nickel (Ni) and gold (Au) by electroplating or the like. ) It is formed by sequentially plating the film.

  As described above, the quartz crystal resonator 2 has excitation electrodes (not shown) formed on both main surfaces, e.g., extended extraction electrodes on both sides of one end thereof, and the bottom surface of the first recess 12 on one main surface of the container body 1. The formed crystal terminal 11 is fixed by, for example, a conductive adhesive 5 in which a conductive filler such as silver particles is mixed in silicone resin. Then, a metal cover 7 is joined to the metal ring 6 provided on the opening end surface of the first frame wall 1c by seam welding and hermetically sealed. On the base of the metal ring 6, a refractory metal metallized layer 61 is provided.

  Thereafter, the vibration characteristics of the crystal resonator 2 are measured by an inspection terminal (not shown) provided on the container body 1 to eliminate defective products, and then the IC chip 3 is accommodated on the other main surface of the container body 1. The surface of the IC chip 3 on which the terminals (IC terminals) 31 (31a-31f) are provided is opposed to the bottom wall 1b, and the IC terminals 31 (31a-31f) are positioned on the electrode pads 17. Gold bumps (Au bumps) 8 (8a-8f) are fixed to the IC terminal 31 by means such as ultrasonic thermocompression bonding. The IC chip 3 is positioned as described above, and ultrasonic waves are applied in a heated and pressurized state to bond the gold bumps 8 (8a-8f) and the electrode pads 17.

  The bottom surface of the container body 1 protects the formation surface of the terminals 31 (31a-31f) of the IC chip 3 and uses an epoxy resin or the like as an underfill layer for fixing the IC chip 3 in the second recess 13. A protective resin (not shown) made of a thermosetting resin material is dropped or injected with an appropriate nozzle or the like. The protective resin is cured in the heat treatment step after dropping or pouring. In some cases, a protective resin is dropped or injected in an appropriate amount so that a resin film for protecting the IC chip is also formed on the back surface of the IC chip 3 (the surface opposite to the surface on which the IC terminals 31 are formed). Or it can also be set as the IC chip which stuck the protective film on the back surface beforehand.

  The following publications can be cited as prior art documents disclosing the structure of this type of surface mount oscillator and the problem to be described later.

JP 05-235238 A Japanese Patent Application Laid-Open No. 07-297079 Japanese Patent Application Laid-Open No. 07-245474

  As shown in FIG. 3, the IC chip 3 has a Vc (frequency control voltage) terminal 31a connected to the mounting terminal 4a, terminals 31b, 31e connected to the pair of crystal terminals 11 via the inner conductor 18a on the bottom wall, A ground terminal 31c connected to the grounding (GND) mounting terminal 4b via the wiring pattern 16 and a Vcc (power source) terminal 31f connected to the mounting terminal 4d of the power supply voltage Vcc are provided. The mounting terminal 4 a is connected to the terminal 31 a of the IC chip 3 through the via hole 13 c and the wiring pattern 16.

  On the other hand, the metal cover 7 that seals the first recess 12 is connected to the ground (GND) to shield the crystal unit 2 from the external electromagnetic field. The metal cover 7 is connected to the mounting terminal 4b which is the ground terminal through the via hole 13a penetrating the first wall frame 1c and the bottom walls 1a and 1b and the via hole 13b penetrating the second frame walls 1d and 1e and connected to the via hole 13a. doing. As described above, the mounting terminal 4 b is also connected to the ground terminal 31 c of the IC chip via the wiring pattern 16. That is, the ground terminal 31c of the IC chip is connected to the via hole 13a connected to the metal cover 7 through the wiring pattern 16, and is connected to the mounting terminal 4b which is the ground terminal via the via hole 13b.

  When the conventional surface mount oscillator 100 having such a structure is mounted on a circuit board or the like, the surface mount oscillator 100 is positioned on an electrode terminal of the circuit board and heated in a reflow furnace or the like (hereinafter referred to as a reflow furnace). As described above, the metal cover 7 is directly connected to the mounting terminal 4b. Therefore, the heat in the reflow furnace is heated by heating the metal cover 7 having a large area earlier, and the high heat by this heating is directly connected to the metal cover 7 through the via hole 13a among the plurality of mounting terminals. Conducted to the mounting terminal 4b, the mounting terminal 4b is heated before the other mounting terminals, and the temperature is raised earlier than the other mounting terminals.

  FIG. 4 is a schematic diagram for explaining the problems of the prior art. FIG. 4A shows a state in which the so-called Manhattan phenomenon occurs in the surface-mounted oscillator 100 in which one or a plurality of the mounting terminals serves as a fulcrum and the other mounting terminal portion rises from the mounting surface of the circuit board 15. FIG. 4B is a schematic diagram for explaining the state of occurrence of the Manhattan phenomenon in more detail by enlarging the portion surrounded by the circle in FIG.

  In FIG. 4, when the surface mount oscillator 100 having the structure as described above is mounted on the circuit board 15 or the like of the applicable device with the mounting terminals 4, cream solder is applied to the electrode pads 17 formed on the circuit board 15. To do. The mounting terminals 4 of the surface mount oscillator 100 are positioned thereon and passed through a reflow furnace (not shown).

  In the reflow furnace, the solder 19 of the cream solder on the electrode pad 17 melts and wets and adheres to the mounting terminals 4 of the surface mount oscillator 100 to form a solder fillet. After leaving the reflow furnace, the solder cools and hardens. And the mounting terminal 4 are electrically and mechanically connected. As shown in FIG. 4B, when the solder cools and hardens, a shrinkage force F is generated in the solder fillet. In normal reflow, substantially the same solder fillet is formed in all the mounting terminals, and there is no great difference in contraction force when the fillet melts and hardens.

  However, if there is a gradient or variation in the heating temperature in the reflow furnace, the amount of cream solder applied on the electrode pad 17 will be slightly positioned, the electrode pad 17 and the mounting terminal 4 will be positioned, or the cream on the electrode pad 17. Differences in the volume and shape of the melted solder fillet formed between the plurality of mounting terminals are caused by differences in heat transfer to the solder. In the surface mount crystal oscillator having the structure described with reference to FIG. 3, the mounting terminal 4 (4B) directly connected to the metal cover 7 is heated to a temperature higher than other mounting terminals, and the solder 19b of the terminal However, it melts before the solder 19a of the other mounting terminals (here, 4A).

  Therefore, the balance between the melting rate and the curing rate of the solder between the mounting terminals is lost, and as shown in FIG. 4B, the force F at the time of melting and shrinking of the solder at the mounting terminal 4B is equal to that of the solder at the mounting terminal 4A. By winning, the surface-mounted oscillator 100 receives the rotational force R with the mounting terminal 4B as a fulcrum, and the above-described Manhattan phenomenon occurs.

  The object of the present invention is to seal the housing of the crystal resonator and to conduct high heat of reflow directly to the grounding mounting terminal along the ground path of the metal cover that shields the external electromagnetic field to the crystal resonator. An object of the present invention is to provide a surface-mount crystal oscillator that has improved reliability by avoiding poor connection due to unstable solder fillet formation between mounting terminals during mounting.

  (1) A surface-mount crystal oscillator according to the present invention includes a container body having a recess formed by laminating a bottom wall and a frame wall having a rectangular shape made of ceramics, and a crystal resonator and the crystal vibration in the recess. And an IC chip in which a circuit constituting an oscillation circuit and the like are integrated together with a child, and a metal cover that seals a concave portion in which the crystal resonator is accommodated and shields it from an external electromagnetic field, and the metal of the container body A surface-mount crystal oscillator having a plurality of mounting terminals including a ground terminal on the opposite side of the cover.

  (2) The IC chip housed in the surface-mount crystal oscillator according to the present invention has two ground terminals commonly connected therein, one of which is formed on the bottom wall of the container body. The first conductive path connected to the ground terminal of the mounting terminal through a wiring pattern and a via hole formed in the frame wall.

  (3) The other of the ground terminals of the IC chip is connected to the metal cover through a wiring pattern different from the wiring pattern formed on the bottom wall of the container body and a via hole formed in the frame wall. 2 conductive paths.

  (4) The frame wall may be laminated on one main surface and the other main surface of the bottom wall. In this case, the crystal frame is housed in a first recess formed by the bottom wall and a first frame wall stacked on one main surface thereof, and a second frame wall stacked on the bottom wall and the other main surface. The IC chip is accommodated in the second recess formed in step (b).

  (5) The frame wall may be laminated only on one main surface of the bottom wall. In this case, both the crystal resonator and the IC chip are accommodated in a recess formed by the bottom wall and the frame wall laminated on one main surface thereof.

  (6) The routing length of the second conductive path is formed longer than the routing length of the first conductive path, and reduces the amount of heat transfer from the metal cover to the terminals of the IC chip and the mounting terminals. .

  (7) As the IC chip, an IC chip in which a temperature compensation circuit is integrated in addition to the oscillation circuit can be used. In addition, as said IC chip, the various incidental circuits which flourish a known crystal oscillator, such as a temperature control circuit, can also be integrated.

  (8) It goes without saying that the present invention can be variously modified without departing from the technical idea of the invention described in the claims.

  According to the surface-mounted crystal oscillator according to the present invention having the above-described configuration, the quartz resonator housing is sealed, and the ground path of the metal cover and the ground path of the IC chip that shield the external electromagnetic field to the crystal resonator This prevents the connection failure between the mounting terminal and the electrode pad of the circuit board at the time of heat mounting using reflow or the like due to the same.

  Further, it can be avoided that the solder joining the terminals of the IC chip is remelted by the heat treatment in the reflow or the like for mounting the surface mount crystal oscillator to cause a defect in the joining of the terminals.

It is explanatory drawing of the structure of Example 1 of the surface mount oscillator which concerns on this invention. It is explanatory drawing of the structure of Example 2 of the surface mount oscillator which concerns on this invention. It is explanatory drawing of the structural example of the conventional surface mount oscillator. It is a schematic diagram of the surface mount oscillator explaining the problem of the prior art.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram of Embodiment 1 of a surface mount oscillator according to the present invention. 1A is a longitudinal sectional view, and FIG. 1B is a bottom view of the surface-mounted oscillator as viewed from the direction of the thick arrow A in FIG. This bottom surface is a mounting surface of the applied device on a circuit board or the like. The surface-mounted oscillator 100 according to the first embodiment includes a container body including bottom walls 1a and 1b, a first frame wall 1c, and second frame walls 1d and 1e that are formed of a laminated ceramic sheet (green sheet) having a rectangular shape in plan view. 1 includes a crystal resonator 2 and an IC chip 3. In addition, the said number of lamination | stacking of a bottom wall or a frame wall is an example.

  The container body 1 is formed by a first frame wall 1c on one main surface (upper side surface of the paper in FIG. 1: the bottom wall 1a side) of the bottom walls 1a and 1b formed of a laminated ceramic sheet similar to the above-described conventional example. A first recess 12 is provided. The crystal resonator 2 is accommodated in the first recess 12.

  The other main surface of the bottom walls 1a and 1b (the lower side of the paper in FIG. 1: the bottom wall 1b side) has a second recess 13 formed by the second frame walls 1d and 1e. As shown in FIG. 1B, the IC chip 3 is accommodated. A plurality of mounting terminals 4 for planar mounting electrically connected to the IC chip 3 are provided on the opening end surfaces of the second frame walls 1d and 1e (in the first embodiment, one each at the four corners, a total of four: 4a, 4b). , 4c, 4d). Electricity between the terminals 31a, 31b, 31c-1, 31c-2, 31d, 31e, 31f of the IC chip 3 and terminals for plane mounting (hereinafter also simply referred to as mounting terminals) 4 (4a, 4b, 4c, 4d) The connection is made through a wiring pattern 16 provided in the ceramic sheet and via holes 13b and 13c, or through a connection conductor (also not shown) formed in a notch (castellation) provided in the side wall surface of the container body 1. .

  The container body 1 is formed by firing such a laminate of ceramic sheets. The mounting terminal 4 is formed of a metal (a high melting point metal such as tungsten: W or molybdenum: Mo) on the opening end face of the second frame wall 1e to form a metallized layer, and then a nickel (Ni) film is formed by electroplating or the like. It is formed by sequentially plating a gold (Au) film.

  The quartz crystal resonator 2 has excitation electrodes formed on both main surfaces of a crystal piece (crystal blank), for example, extending extraction electrodes on both sides of one end thereof, and is formed on the bottom surface of the first recess 12 on one main surface of the container body 1. The formed crystal terminal 11 is fixed by, for example, a conductive adhesive 5 in which a conductive filler such as silver particles is mixed in silicone resin. Then, a metal cover 7 is joined to the metal ring 6 provided on the opening end surface of the first frame wall 1c by seam welding and hermetically sealed. A refractory metal metallized layer 61 is formed on the base of the metal ring 6 on the opening end face. Such a structure is the same as the conventional one described above.

  The inner walls of the IC chip 3 and the second recess 13 are filled and filled with a so-called underfill resin (not shown). This resin can also be applied as a protective resin to the back surface of the IC chip 3 (the opening side surface of the second recess 13). Further, instead of the resin on the back surface, a protective resin film can be provided in advance on the back surface of the IC chip 3.

  Thereafter, the vibration characteristics of the crystal resonator 2 are measured by an inspection terminal (not shown) provided on the container body 1 to eliminate defective products, and then the IC chip 3 is mounted and accommodated in the second recess 13 of the container body 1. On the IC chip 3, terminals (IC terminals) 31 (31a, 31b, 31c-1, 31c-2, 31d, 31e, 31f) are formed in the illustrated arrangement. The IC terminal 31a is a Vc terminal, the IC terminals 31b and 31e are crystal connection terminals connected to the crystal terminal 11, and the IC terminals 31c-1 and 31c-2 are the same potential with the IC internal wiring 20 provided inside the IC chip 3. The connected ground (GND) terminal, IC terminal 31d is an output terminal, and IC terminal 31f is a Vcc terminal.

  The IC terminal 31c-1 of the IC chip 3 is connected to the metal cover 7 through the via hole 13d provided in the bottom wall, the inner layer conductor 18b, and the via hole 13a provided in the first frame wall. The IC terminal 31c-2 of the IC chip 3 is connected to the mounting terminal 4b through the wiring pattern 16 provided on the bottom surface of the second recess 13 and the via hole 13b provided in the second frame wall. The IC terminal 31c-1 and the IC terminal 31c-2 of the IC chip 3 are connected to each other at the same potential inside the IC chip 3, and the metal cover 7 is connected to the mounting terminal 4b.

  When the IC chip 3 is mounted and accommodated in the second recess 13 of the container body 1, the IC terminals 31 (31a, 31b, 31c-1, 31c-2) of the IC chip 3 are placed with the second recess 13 facing upward. , 31d, 31e, 31f) are made to face the bottom wall 1b, and IC terminals 31 (31a, 31b, 31c-1, 31c-2, 31d, 31e, 31f). Gold bumps (Au bumps) 8 (8a, 8b, 8c-1, 8c-2, 8d, 8e, 8f) are fixed to the IC terminal 31 by means such as ultrasonic thermocompression bonding. Each electrode corresponding to the gold bumps 8 (8a, 8b, 8c-1, 8c-2, 8d, 8e, 8f) is obtained by positioning the IC chip 3 as described above and applying ultrasonic waves in a heated and pressurized state. The pad 17 is joined.

  When the surface-mounted oscillator 100 configured in this way is mounted on a circuit board or the like of an applied device, as described with reference to FIG. 4, cream solder is applied to the electrode pads formed on the circuit board or the like. Reflow process. In the surface mount oscillator 100 according to the present embodiment, the configuration described above, that is, the configuration in which heat from the metal cover 7 at the time of reflow is directly transmitted to a specific terminal of the mounting terminal 4 and there is no non-uniform solder melting between the terminals. As a result, the occurrence of mounting defects such as the Manhattan phenomenon described above is prevented.

  As described above, according to the first embodiment, the second conductive path from the metal cover 7 through the IC terminals 31c-1 and 31c-2 to the ground terminal 4b passes through the IC terminal 31c-2 and the ground terminal 4b. It is longer than the first conductive path leading to. The soldering failure such as the Manhattan phenomenon as described in the prior art does not occur. Further, since high heat from the metal cover 7 is not transmitted to the specific IC terminal, it is possible to provide a highly reliable surface mount oscillator that does not cause poor soldering to the IC terminal of the IC chip.

  FIG. 2 is an explanatory diagram of Embodiment 2 of the surface mount oscillator according to the present invention. 2A is a vertical cross-sectional view, and FIG. 2B is a bottom view of the surface mount oscillator as viewed from the direction of the thick arrow A in FIG. 2A. This bottom surface is a mounting surface of the applied device on a circuit board or the like. In the surface-mounted crystal oscillator according to the second embodiment, the mounting surface on which the mounting terminals are provided is the bottom wall plane itself. Therefore, as shown in FIG. Is not exposed on the mounting surface. Therefore, in FIG. 2B, an IC chip or the like is virtually shown by a chain line.

  Similar to the first embodiment, the surface-mounted oscillator 100 according to the second embodiment includes bottom walls 1a and 1b and first frame walls 1c, 1d, and 1e formed of a laminated ceramic sheet (green sheet) having a rectangular shape in plan view. The quartz resonator 2 and the IC chip 3 are accommodated in the common recess 14 of the container body 1 in the vertical direction. In addition, the said number of lamination | stacking of a bottom wall or a frame wall is an example.

  The container body 1 is formed of frame walls 1c, 1d, and 1e on one main surface (upper side surface of the paper in FIG. 1: the bottom wall 1a side) of the bottom walls 1a and 1b formed of the same laminated ceramic sheet as in the conventional example described above. Common recesses 14 are provided. The IC chip 3 is accommodated on the bottom side of the common recess 14, and one end of the crystal resonator 2 is fixedly supported by a step formed by the frame walls 1d and 1c.

  On the other main surface of the bottom walls 1a and 1b (mounting surface, lower side surface of FIG. 2: bottom wall 1b side), a plurality of mounting terminals 4 for planar mounting electrically connected to the IC chip 3 are provided (Example 1). Then, each of the four corners has a total of four: 4a, 4b, 4c, 4d). The electrical connection between the IC chip 3 and the flat mounting terminal (mounting terminal) 4 is made through the conductor patterns 16 and 18 and the via holes 13b and 13c provided in the ceramic sheet, or in the notch provided on the side wall surface of the container body 1 ( This is done through a connection conductor (also not shown) formed in the castellation.

  The container body 1 is formed by firing such a laminate of ceramic sheets. The mounting terminal 4 is formed by baking a metal (a refractory metal such as tungsten: W or molybdenum: Mo) near the edge of the bottom wall 1b to form a metallized layer, and then a nickel (Ni) film and a gold by electroplating or the like. (Au) A film is formed by sequentially plating.

  The crystal resonator 2 is the same as that of the first embodiment, and a conductive adhesive 5 in which a conductive filler such as silver particles is mixed in a crystal terminal 11 provided at a step formed on the frame wall 1d, for example, in a silicone resin. Fixed by. Then, after adjusting the vibration frequency (oscillation frequency) of the crystal resonator 2, the metal cover 7 is joined to the metal ring 6 provided on the opening end surface of the first frame wall 1c by seam welding and hermetically sealed. A refractory metal metallized layer 61 is formed on the base of the metal ring 6 on the opening end face. Such a structure is the same as described above.

  A so-called underfill resin is provided to fill the space between the bottom surface of the common recess 14 and the IC chip 3 (not shown).

  On the IC chip 3, IC terminals 31a, 31b, 31c-1, 31c-2, 31d, 31e, 31f are formed in the illustrated arrangement. IC terminal 31a is a Vc terminal, IC terminals 31b and 31e are crystal connection terminals connected to crystal terminal 11, IC terminals 31c-1 and 31c-2 are ground (GND) terminals connected to each other at the same potential, and IC terminals 31d is an output terminal, and IC terminal 31f is a Vcc terminal. This is the same as that of the first embodiment.

  The IC terminal 31c-1 of the IC chip 3 is connected to the metal cover 7 through the via hole 13c provided in the bottom wall, the inner layer conductor 18, and the via hole 13a provided in the frame wall. The IC terminal 31c-2 of the IC chip 3 is connected to the mounting terminal 4b which is a ground terminal through the wiring pattern 16 provided on the bottom surface of the common recess 14 and the via hole 13b provided in the frame wall. The IC terminal 31 c-1 and the IC terminal 31 c-2 of the IC chip 3 are connected to each other at the same potential by the IC internal wiring 20 inside the IC chip 3. That is, the metal cover 7 is connected to the mounting terminal 4b which is a ground terminal through the via hole 13a, the interior conductor 18, the via hole 13c, the IC terminal 31c-1, the IC internal wiring 20, the IC terminal 31c-2, the wiring pattern 16, and the via hole 13b. Therefore, the high heat of the metal cover 7 is not directly conducted to the mounting terminal 4b.

  The IC chip 3 has the common recess 14 facing upward, and the surface of the IC chip 3 on which the IC terminals 31 (31a, 31b, 31c-1, 31c-2, 31d, 31e, 31f) are provided is the bottom of the common recess 14 The IC terminals 31 (31a, 31b, 31c-1, 31c-2, 31d, 31e, 31f) are positioned on the corresponding electrode pads 17 provided on the wall 1a. Gold bumps (Au bumps) 8 (8a, 8b, 8c-1, 8c-2, 8d, 8e, 8f) are fixed to the IC terminal 31 by means such as ultrasonic thermocompression bonding. With the IC chip 3 positioned, heat and pressure are applied, and ultrasonic waves are applied to join the electrode pads 17 corresponding to the gold bumps 8 (8a, 8b, 8c-1, 8c-2, 8d, 8e, 8f). To do.

  When the surface-mounted oscillator 100 configured in this way is mounted on a circuit board or the like of an applied device, as described with reference to FIG. 4, cream solder is applied to the electrode pads formed on the circuit board or the like. Reflow process. In the surface mount oscillator 100 according to the present embodiment, since the above-described configuration is used, high heat from the metal cover 7 is not directly transmitted to any mounting terminal including the mounting terminal 4b during reflow.

  Also in the second embodiment, the second conductive path from the metal cover 7 through the IC terminals 31c-1 and 31c-2 to the ground terminal 4b is the first conductive path from the IC terminal 31c-2 to the ground terminal 4b. Longer than. The soldering failure such as the Manhattan phenomenon as described in the prior art does not occur.

  The present invention is not limited to the crystal oscillator described in the above embodiment, but can also be applied to piezoelectric parts using the same underfill, MEMS, and other microelectronic parts for planar mounting.

  1 .. Container body, 2 .. Crystal resonator, 3 .. IC chip, 4 .. Mounting terminal, 5 .. Conductive adhesive, 6 .. Metal ring, 7 .. Metal cover (lid), 8 ··· Gold bumps, 11 ·· Crystal terminals, 12 · · First recess, 13 · · Second recess, 14 · · Common recess, 16 · · Wiring pattern, 17 · · Electrode pad, 18 · · Inner layer conductor, 19 .. Solder, 20 ... IC internal wiring, 31 ... IC terminal, 100 ... Surface mount oscillator.

As described above, according to the first embodiment, the second conductive path from the metal cover 7 through the IC terminals 31c-1 and 31c-2 to the ground terminal 4b passes through the IC terminal 31c-2 and the ground terminal 4b. It is longer than the first conductive path leading to. The soldering failure such as the Manhattan phenomenon as described in the prior art does not occur.

Claims (5)

An IC in which a container body having a recess formed by laminating a bottom wall having a rectangular shape in plan view and a frame wall made of ceramics, and a crystal oscillator and a circuit constituting an oscillation circuit together with the crystal oscillator are integrated in the recess A plurality of mountings including a metal cover that contains a chip, seals a recess in which the crystal resonator is housed and shields it from an external electromagnetic field, and a ground terminal on the opposite surface of the container body from the metal cover A surface mount crystal oscillator having a terminal,
The IC chip has two IC terminals for grounding connected therein, one of which is the mounting terminal through a wiring pattern formed on the bottom wall of the container body and a via hole formed on the frame wall. The other of the ground terminals is connected to a wiring pattern different from the wiring pattern formed on the bottom wall of the container body and a via hole formed on the frame wall. A crystal oscillator for surface mounting, which is connected to a second conductive path connected to the metal cover. In claim 1,
The frame wall is laminated on one main surface and the other main surface of the bottom wall, and the quartz crystal vibration is formed in a first recess formed by the bottom wall and a first frame wall laminated on the one main surface. A crystal oscillator for surface mounting, wherein a child is housed, and the IC chip is housed in a second recess formed by a second frame wall laminated on the bottom wall and the other main surface. In claim 1,
The frame wall is laminated only on one main surface of the bottom wall, and both the crystal resonator and the IC chip are accommodated in a recess formed by the bottom wall and the frame wall laminated on the one main surface. A crystal oscillator for surface mounting, characterized in that In claim 1,
The surface-mount crystal oscillator, wherein the length of the second conductive path is longer than the length of the first conductive path. In claim 1,
The surface-mount crystal oscillator according to claim 1, wherein the IC chip includes a temperature compensation circuit.

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