JP2007180701A - Piezoelectric oscillator and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator having a structure of which thickness is suitably reduced, and to provide a method for manufacturing the piezoelectric oscillator which is easy to handle and superior in productivity. <P>SOLUTION: In the piezoelectric oscillator, which is composed of a piezoelectric vibrating element, an integrated circuit element internally having at least an oscillation circuit provided with an electrode pad for mounting the piezoelectric vibrating element, a wiring board on which the integrated circuit element is mounted, and a cover body in a nearly box shape for airtightly sealing the piezoelectric vibrating element and integrated circuit element, a space part is formed between the integrated circuit element and a wiring board, the electrode pad for mounting the piezoelectric vibrating element is formed on an integrated circuit element surface facing the space part, and the piezoelectric vibrating element is mounted on the electrode pad for mounting the piezoelectric vibrating element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric oscillator used in an electronic device such as a portable communication device and a method for manufacturing the same.

  For some time, piezoelectric oscillators such as crystal oscillators (TCXO) having a built-in temperature compensation function have been widely used as timing devices incorporated in electronic devices such as portable communication devices.

  As an outline of such a conventional piezoelectric oscillator, for example, as shown in FIG. 5, a first container body 51 in which a crystal vibration element 54 as a piezoelectric vibration element is accommodated is connected to a plurality of external connections on the outer bottom surface. Electrode terminal 55 is provided on a second container body 53 containing an integrated circuit element 52 in which an oscillation circuit, a temperature compensation circuit, and the like for controlling various oscillation outputs from the crystal oscillation element 53 are housed. It arrange | positions in the form which overlaps, The 2nd container body connection electrode terminal 56 formed in the outer bottom face of the 1st container body 51, and the 1st formed in the side wall part top surface of the 2nd container body 53 There is known a structure in which the container body connection electrode terminal 57 is conductively fixed through a conductive bonding material such as solder.

  During the assembly process of the piezoelectric oscillator having such a structure, the opening of the first container body 51 is formed by attaching a metal lid 58 to the first container body 51 by a conventionally known seam welding (resistance welding) or the like. The quartz vibration element 54 mounted in the first container body 51 is hermetically sealed by being bonded to the top surface of the side wall portion.

  In addition, as a method for manufacturing such a conventional piezoelectric oscillator, normally, only a first container body 51 and a second container body 53 are used, and a container body wafer in which a plurality of container body formation regions are arranged in a matrix. From each of the first container body 51 and the second container body 53 obtained by dividing and cutting along the outer periphery of the container body forming region and simultaneously obtaining a plurality of individual container bodies. A method of assembling a piezoelectric oscillator by mounting the crystal resonator element 54 and the integrated circuit element 52 individually and joining them together after various processes has been used.

The piezoelectric oscillator and the method for manufacturing the piezoelectric oscillator as described above are disclosed in the following prior art documents.
Japanese Patent No. 2974622 JP-A-2005-94241

  In addition, the applicant has not found any prior art documents related to the present invention by the time of filing of the present application other than the prior art documents specified by the information of the above prior art documents.

  However, in the structure like the conventional piezoelectric oscillator described above, the first container body 51 on which the piezoelectric vibration element is mounted and the second container body 53 on which the integrated circuit element 52 is mounted are arranged in the vertical direction. The thickness of the piezoelectric oscillator as a whole may increase. Therefore, there is a drawback that it may be difficult to meet the demand for reducing the height (thinning) of the piezoelectric oscillator while keeping the mounting area of the piezoelectric oscillator small.

  In the piezoelectric oscillator manufacturing method described above, after the second container body is divided and cut into individual pieces, the step of mounting the integrated circuit element inside, or the first container body is placed on the second container body. In the mounting process, it is necessary to individually hold the second container body with a carrier or the like until the process is completed, and the assembly work of the piezoelectric oscillator is complicated, and the manufacturing equipment for the holding carrier and the like However, this has the disadvantage that the productivity of the piezoelectric oscillator may be lowered.

  The present invention has been devised in view of the above-described drawbacks, and an object of the present invention is to provide a piezoelectric oscillator having a structure suitable for thinning and a method for manufacturing the piezoelectric oscillator that is easy to handle and excellent in productivity. is there.

A piezoelectric oscillator according to the present invention includes a piezoelectric vibration element, an integrated circuit element including at least an oscillation circuit provided with a piezoelectric vibration element mounting electrode pad for mounting the piezoelectric vibration element, and the integrated circuit element. In a piezoelectric oscillator composed of a wiring board and a substantially box-shaped lid for hermetically sealing the piezoelectric vibration element and the integrated circuit element,
A space portion is formed between the integrated circuit element and the wiring board, and an electrode pad for mounting a piezoelectric vibration element is formed on the surface of the integrated circuit element facing the space portion. A piezoelectric vibration element is mounted on the pad.

In addition, a method for manufacturing a piezoelectric oscillator according to the present invention includes
Each integrated circuit element is formed on an integrated circuit element wafer formed by connecting a plurality of integrated circuit element forming regions in a matrix form on one main surface where electrode pads for substrate connection and electrode pads for mounting piezoelectric vibration elements are formed. Mounting the piezoelectric vibration element on the piezoelectric vibration element mounting electrode pad in the region, and forming a conductive bonding material on the substrate connection electrode pad; and
Cutting the integrated circuit element wafer on which the piezoelectric vibration element is mounted along the periphery of each integrated circuit element forming region to form individual integrated circuit elements on which the piezoelectric vibration element is mounted; and
An integrated circuit element on which a piezoelectric vibration element is mounted on a master substrate having a plurality of wiring board regions is arranged in a form in which the piezoelectric vibration element is directed to the master substrate side while holding the other main surface of the integrated circuit element. A step C in which the individual integrated circuit elements and the master substrate are fixedly connected to each other by a conductive bonding material in a form in which the piezoelectric vibration element surface is not brought into contact with the master substrate surface and the integrated circuit element surface;
Step D for covering the individual integrated circuit elements on which the piezoelectric vibration elements mounted on the master substrate are covered with a substantially box-shaped cover body so as to hermetically seal the lid body in which the integrated circuit elements are embedded. When,
And a step E of individually obtaining a plurality of piezoelectric oscillators by cutting the master substrate along the outer periphery of the wiring board region.

  According to the piezoelectric oscillator of the present invention, the space portion having a predetermined interval is formed between the integrated circuit element and the wiring board by the conductive bonding material, and the piezoelectric vibration element is formed on the surface of the integrated circuit element facing the space portion. A mounting electrode pad is formed, and the piezoelectric vibration element mounted on the electrode pad for mounting the piezoelectric vibration element makes it possible to make the entire structure of the piezoelectric oscillator significantly thinner than the conventional example. It is possible to make the oscillator thinner.

  In addition, since the piezoelectric vibration element is mounted on the surface of the integrated circuit element, the excitation electrode formed on the piezoelectric vibration element is directly connected to the electrode pad for connecting the piezoelectric vibration element of the integrated circuit element. Compared to the case where the integrated circuit element and the piezoelectric vibration element are mounted in different containers, the length of the wiring connecting the piezoelectric vibration element and the electronic circuit in the integrated circuit element is shortened, and the capacitance caused by the wiring resistance. Can be effectively prevented, and an oscillation characteristic close to the design value can be obtained.

  Furthermore, according to the method for manufacturing a piezoelectric device of the present invention, since the master substrate functions as a carrier member during the piezoelectric oscillator manufacturing process, an individual wiring substrate obtained by separately preparing a carrier member and dividing the master substrate into the carrier member No complicated work such as mounting is required, and the productivity of piezoelectric devices can be dramatically improved.

  Further, when the individual integrated circuit elements on which the piezoelectric vibration element and the conductive bonding material are mounted or formed on one main surface are arranged at predetermined positions in each wiring board region of the master substrate, the other of the integrated circuit elements is arranged. Can be transported to the placement position by chucking the main surface (for example, vacuum chucking using a vacuum suction disk), without using a transport method in which the side surface of the integrated circuit element on which the piezoelectric vibration element is mounted is sandwiched In fact, since unnecessary and harmful stress is not applied to the integrated circuit element, it is possible to reduce the occurrence of defective piezoelectric oscillators due to the defect of the integrated circuit element.

  As described above, the piezoelectric oscillator and the manufacturing method thereof according to the present invention provide a thin piezoelectric oscillator with good characteristics while keeping the mounting area of the piezoelectric oscillator small, and further improve the productivity and the manufacturing yield. There exists an effect which can provide the manufacturing method of a good piezoelectric oscillator.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol in each figure shall show the same object. Moreover, in each figure, in order to clarify explanation, a part of a part or a structure is not shown, and the illustrated dimension is also exaggerated in part. In particular, the thickness dimension of each drawing is greatly exaggerated.

  FIG. 1 is an exploded perspective view showing an example in which a piezoelectric oscillator according to an embodiment of the present invention is applied to a surface-mount type crystal oscillator, and FIG. 2 shows an integrated circuit element 2 shown in FIG. It is the external appearance perspective view shown from. FIG. 3 is a schematic sectional view when the crystal oscillator shown in FIG. 1 is assembled. The crystal oscillators shown in these drawings are roughly composed of a wiring board 1, an integrated circuit element 2, a crystal vibration element 3 as a piezoelectric vibration element, a lid 4, and a conductive bonding material 5. Yes.

  A plurality of external connection electrode terminals 6 are provided on the other main surface (the surface facing the external mounting substrate) of the flat wiring board 1 having a rectangular main surface. In the present embodiment, four external connection electrode terminals 6 formed at the four corners of the other main surface of the wiring board 1 are provided, respectively, as a power supply voltage terminal, a ground terminal, an oscillation output terminal, and an oscillation control terminal. Function. These external connection electrode terminals 6 are electrically connected to circuit wiring of the external electric circuit by soldering or the like when the crystal oscillator is mounted on an external electric circuit such as an external mounting substrate (motherboard).

  The main structural material of the wiring board 1 is formed of, for example, a ceramic material such as glass-ceramic or alumina ceramic, or an organic material such as resin.

  Further, the integrated circuit element 2 is arranged on one main surface of the wiring board 1 in a form in which a space portion 14 having a desired interval is formed via a conductive bonding material 5 made of bumps. Is mounted on the main surface of the integrated circuit element 2 facing the wiring board and is disposed so as to be positioned in the space 14. Excitation electrodes formed on the crystal vibration element 3 are electrically connected to the piezoelectric vibration element mounting electrode pads 7 provided on the main surface of the integrated circuit element 2 facing the wiring board via a conductive adhesive. Further, a sealing conductor pattern 9 is deposited on the entire outer peripheral edge of one main surface of the wiring board 1.

  When the wiring board 1 is made of alumina ceramic, for example, an appropriate organic solvent is added to and mixed with the raw material powder of the alumina ceramic, and then formed into a predetermined shape by a conventionally known doctor blade method or the like. It is manufactured by obtaining ceramic green sheets, applying conductive paste to be a connection pad or sealing conductor pattern on the surface, etc. to a predetermined pattern, laminating a plurality of them, press molding, and firing at high temperature Yes.

  On one main surface of the wiring board 1, a flip-chip type integrated circuit element 2 is mounted. A crystal resonator element 3 is mounted on the main surface of the integrated circuit element 2 facing the wiring board, and the crystal resonator element 3 is a rectangular plate-shaped crystal piece that is cut out from the artificial crystal at a predetermined cut angle and processed in outline. A pair of excitation electrodes are deposited on both main surfaces, and when an externally varying voltage is applied to the crystal piece via the pair of excitation electrodes, vibration occurs in a predetermined vibration mode and frequency. The quartz resonator element 3 is electrically connected to a corresponding piezoelectric resonator element mounting electrode pad 7 provided with a pair of excitation electrodes on the main surface of the integrated circuit element 2 facing the wiring board via a conductive adhesive. As a result, it is mounted on the main surface of the integrated circuit element 2 facing the wiring board, and in this state, it is disposed in the space 14 formed between the integrated circuit board 2 and the wiring board 1.

  In this way, if the crystal resonator element 3 is mounted on the main surface of the oscillation integrated circuit element 2 facing the wiring board, the excitation electrode of the crystal oscillator element 3 is the electrode pad for mounting the piezoelectric resonator element of the integrated circuit element 2. 7, the integrated circuit element 2 and the crystal vibration element 3 are built in the crystal vibration element 3 and the integrated circuit element 2 as compared with the piezoelectric oscillator in the case where the integrated circuit element 2 and the crystal vibration element 3 are mounted in separate containers. The length of the wiring that electrically connects the electronic circuit such as the oscillation circuit is remarkably shortened, and the generation of capacitance due to the wiring resistance can be effectively prevented. Thereby, an oscillation characteristic close to the design value theoretical value can be obtained.

  In the integrated circuit element 2, temperature compensation data for compensating the temperature characteristics of the temperature sensing element (thermistor) for detecting the ambient temperature state and the crystal vibration element 3 are stored on the lower surface of the substrate made of single crystal silicon or the like. An electronic circuit such as a temperature compensation circuit that corrects the vibration characteristics of the crystal resonator element 3 according to a temperature change based on the temperature compensation data and an oscillation circuit that is connected to the temperature compensation circuit and generates a predetermined oscillation output is provided. The oscillation output generated by the oscillation circuit described above is output to the external mounting board side and then used as a reference signal such as a clock signal or timing signal of another electronic component or electronic device. It becomes.

  The integrated circuit element 2 is obtained by slicing a single crystal silicon ingot to a predetermined thickness to obtain a silicon wafer, and adopting a well-known semiconductor manufacturing technique on one main surface thereof, an electronic circuit such as an oscillation circuit and various electrode pads. And the like are obtained by cutting and dividing the integrated integrated circuit element wafer 10 manufactured for each of the plurality of integrated circuit element forming regions arranged in a matrix along the outer periphery of each integrated circuit element forming region. A conductive bonding material 5 such as a bump is disposed on the substrate connection electrode pad 11 formed on the integrated circuit element 2, and the conductive bonding material 5 is formed on the main surface of the integrated circuit element 2 facing the wiring board. The substrate connection electrode pads 11 and the integrated circuit element connection electrode pads 12 formed on one main surface of the wiring substrate 1 are electrically and mechanically connected.

  The conductive bonding material 5 is used for mechanically and electrically connecting the wiring board 1 and the integrated circuit element 2, and at the same time, mounted on the integrated circuit element 2 between the wiring board 1 and the integrated circuit element 2. The crystal resonator element 3 that has been provided has a function of maintaining a space portion 14 that is not in contact with the surface of the wiring substrate 1 and the surface of the integrated circuit element 2. The conductive bonding material 5 may be a brazing material or a metal member in addition to the bump.

  In this way, by arranging the crystal resonator element 3 in the space portion 14 formed between the integrated circuit element 2 and the wiring substrate 1, the entire piezoelectric (crystal) oscillator can be formed thinner than in the conventional example. Therefore, the piezoelectric (crystal) oscillator can be thinned.

  The lid 4 is an outline having, for example, a metal plate made of metal such as 42 alloy, Kovar, phosphor bronze, etc., having a thickness of 60 μm to 100 μm, and having a brim-like wiring board joint around the opening by a conventionally known sheet metal processing. Manufactured by processing into a box shape. The lid 4 is for accommodating the integrated circuit element 2 on which the crystal resonator element 5 arranged and fixed on the wiring substrate 1 is mounted and hermetically sealed. Further, the lid 4 is a wiring of the lid 4. Electrically connected to the ground terminal of the external connection electrode terminals 6 formed on the other main surface of the wiring board 1 through the sealing member 13 and the sealing conductor pattern 9 formed on the substrate bonding portion surface. The As a result, the lid 4 is held at the ground potential when the crystal oscillator is used, and the quartz resonator element 3 is well protected from unnecessary external electrical action such as noise due to the electromagnetic shielding effect of the lid 4. Is done. As the sealing member 13, for example, a brazing material made of metal such as Au, Au—Sn alloy, or solder is preferably used.

  Next, the manufacturing method of the above-described crystal oscillator (piezoelectric oscillator) will be described with reference to FIGS. 4A to 4E.

(Process A)
First, as shown in FIG. 4 (a), a plurality of integrated circuit element formation regions are arranged in a matrix, and on one main surface of each of the integrated circuit element formation regions, a piezoelectric vibration element is mounted. An integrated integrated circuit element wafer 10 on which electrode pads 7 and substrate connection electrode pads 11 are formed is prepared. The integrated circuit element wafer 10 is obtained by slicing a single crystal silicon ingot to a predetermined thickness to obtain a silicon wafer, and adopting a well-known semiconductor manufacturing technique on one main surface thereof, mounting an electronic circuit such as an oscillation circuit or a piezoelectric vibration element. This is manufactured by forming electrode pads 7 and substrate connection electrode pads 11.

  Then, the crystal vibration element 3 is mounted on the piezoelectric vibration element mounting electrode pad 7 formed on one main surface of each integrated circuit element formation region of the integrated circuit element wafer 10, and the excitation electrode of the crystal vibration element 3 is mounted. (Not shown) and the piezoelectric vibration element mounting electrode pad 7 on the upper surface of the integrated circuit element wafer 10 are electrically and mechanically connected via a conductive adhesive. Further, a conductive bonding material 5 is formed by bumps on each substrate connection electrode pad 11. In the present embodiment, predetermined spare areas are provided between the individual integrated circuit element formation areas arranged in a matrix.

(Process B)
Next, as shown in FIG. 4B, the integrated circuit element wafer 10 on which the crystal resonator element 3 is mounted in each integrated circuit element formation region is cut with a dicer along the outer periphery of the integrated circuit element formation region and discarded. A plurality of integrated circuit elements 2 on which the crystal resonator element 3 and the conductive bonding material 5 are mounted on the surface are obtained by separating the substitution area.

(Process C)
Next, as shown in FIG. 4C, a plurality of wiring board formation regions are arranged in a matrix and an integrated circuit element mounting electrode pad 12 is formed on one main surface of each wiring board formation region. And an integrated master substrate 15 in which the external connection electrode terminal 6 is formed on the other main surface, and the integrated circuit element 2 on which the crystal resonator element 3 is mounted is integrated circuit While holding the other main surface of the element 2, the crystal resonator element 3 is individually arranged in each wiring board region in a form facing the master substrate 15, and between the integrated circuit element 2 and the wiring board forming region. The integrated circuit element 2 and the master substrate 15 are fixedly connected by the conductive bonding material 5 in a form in which the space portion 14 is formed and the surface of the crystal resonator element 3 is not brought into contact with the surface of the master substrate 15 and the surface of the integrated circuit element 2. In the present embodiment, a predetermined spare area is provided between the individual wiring board forming areas arranged in a matrix.

  The master substrate 15 is a flat substrate made of the same material as the wiring substrate 1 described above, that is, a ceramic material such as glass-ceramic and alumina ceramics. For example, an organic solvent suitable for a ceramic material powder made of alumina ceramics or the like. A conductive paste to be used as a connection electrode pad, external connection electrode terminal 6, sealing conductor pattern 9 or the like is printed and applied in a predetermined pattern on the surface of the ceramic green sheet obtained by adding and mixing It is manufactured by laminating a plurality of sheets and press-molding them, followed by firing at a high temperature.

  In the present embodiment, each integrated circuit element 2 in which the crystal resonator element 3 and the conductive bonding material 5 are mounted or formed on one main surface has the other main surface of the integrated circuit element 2 attached to the vacuum suction disk. 16 is held by vacuum chucking, and transported to a predetermined position in each wiring board region of the master board 15 and arranged. This method eliminates the need to use a transport method in which the side surface of the integrated circuit element 2 on which the crystal resonator element 3 is mounted is sandwiched, and eliminates unnecessary and harmful stress on the integrated circuit element 2. The generation of defective piezoelectric oscillators due to the above problems can be reduced.

(Process D)
As shown in FIG. 4D, a sealing member 13 and a master substrate in which a substantially box-shaped lid 4 having a brim-like wiring board joint around the opening is formed at the wiring board joint of the lid 4. The box-shaped portion of the lid 4 is placed on the integrated circuit element 2 on which the crystal resonator element 3 placed on each wiring board formation region is mounted while matching the sealing conductive pattern 9 formed on each wiring board formation area. By bonding the sealing member 13 and the conductive pattern 9 for sealing, the crystal resonator element 3 and the integrated circuit element 2 in the lid 4 are hermetically sealed.

  The lid 4 is manufactured, for example, by processing a metal plate having a thickness of 60 μm to 100 μm made of metal such as 42 alloy, Kovar, or phosphor bronze into the above-described shape by a conventionally known sheet metal processing. Further, a sealing member 13 made of a nickel (Ni) layer and a gold tin (Au—Sn) layer is formed at the wiring board joint portion of the lid 4. The sealing member 13 functions as a brazing material layer for bonding the lid 4 to each wiring board forming region of the master substrate 15. The composition ratio of gold tin is, for example, 80% gold, tin The thickness is set to 20%, and the thickness is set to, for example, 10 μm to 30 μm.

  Further, the specific bonding method between the individual lid 4 and the wiring board formation region is that each of the wiring board formations of the sealing member 13 and the master board 15 in which the lid 4 is formed at the wiring board bonding portion of the lid 4. The box-shaped portion of the lid 4 is put on the integrated circuit element 2 on which the crystal resonator element 3 placed on each wiring board forming area is covered while the sealing conductive pattern 9 formed in the area is matched, and then this is applied to 300 ° C. Each lid 4 is bonded to the master substrate 15 by placing it in a heating furnace maintained at a temperature of ˜350 ° C. and heating and melting the sealing member 13 at a high temperature and bonding it to the conductive pattern 9 for sealing. Is done. Thereafter, the master substrate 15 and the lid 4 are gradually cooled to room temperature.

  As another bonding method between the lid and the wiring board formation region, the lid 4 is bonded to the master board by irradiating a light beam to the wiring board joint of the lid 4 and melting the sealing member 13. There is a method of sealing each wiring board formation region. At this time, a plurality can be sealed simultaneously.

In the crystal oscillator as described above, the crystal resonator element 3 is first mounted on the lower surface of the oscillation integrated circuit element 2, and then the crystal resonator element 3 having the oscillation integrated circuit element 2 mounted on the lower surface provides an accommodation space. Then, it is placed on the wiring substrate 1 via the conductive member 5, and then heat-treated in an inert gas atmosphere such as N ₂ gas or Ar gas or in a vacuum maintained at a predetermined degree of vacuum, The lid 4 is assembled to the upper surface of the wiring board 1 with the sealing member 13.

  The sealing step described above is preferably performed in a vacuum or in an inert gas atmosphere. It is possible to stabilize the electrical characteristics of the crystal resonator element 3 by filling the space inside the lid 4 in which the crystal resonator element 3 is accommodated with an inert gas. In addition, when sealing is performed in a vacuum, the electrical characteristics of the crystal resonator element 3 can be stabilized, and the crystal impedance of the crystal resonator element 3 can be kept low.

  When using solder as the conductive bonding material 5 or the sealing member 13, it is preferable to use a conventionally known hydrogen reduction method in order to remove the oxide film satisfactorily without using contaminants such as flux. .

(Process E)
Then, as shown in FIG. 4E, the integrated circuit element 2 hermetically sealed with the crystal resonator element 3 is hermetically sealed in each wiring board forming area along the outer periphery of each wiring board forming area. A plurality of piezoelectric oscillators in which the integrated circuit element 2 on which the crystal resonator element 3 is mounted is hermetically sealed by the lid 4 are obtained at the same time by cutting with a dicer or the like.

  In the case of a piezoelectric (quartz) oscillator having a temperature compensation function, a probe needle of a temperature compensation data writing device is connected to a write control terminal (not shown) provided on the outer surface of the wiring board 1 after the above process. The temperature compensation data is stored in the memory of the oscillation integrated circuit element 2 by writing the temperature compensation data corresponding to the temperature characteristics of the crystal resonator element 3 measured in advance, and then externally mounted on an external mounting board or the like. Mounted on the wiring board by soldering or the like, and outputs a predetermined oscillation signal corresponding to the resonance frequency of the crystal resonator element 3 while correcting the oscillation output by the temperature compensation circuit of the integrated circuit element 2 according to the temperature state. .

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. For example, in the above embodiment, a crystal oscillator using a crystal as a piezoelectric material of a piezoelectric vibration element mounted in the oscillator is illustrated, but in addition to the crystal, lithium tantalate, Other piezoelectric materials such as lithium niobate and piezoelectric ceramic may be used as the main material of the piezoelectric vibration element.

  In the above-described embodiment, a surface-mount type crystal oscillator using a crystal resonator element as the piezoelectric resonator element 3 has been described as an example, but instead of this, as the resonator element, other surface acoustic wave resonator elements or the like are used. The present invention can also be applied when a vibration element is used.

FIG. 1 is a schematic exploded perspective view showing an example of a piezoelectric oscillator according to an embodiment of the present invention as a crystal oscillator that is one of the piezoelectric oscillators. FIG. 2 is an external perspective view showing the integrated circuit element 2 shown in FIG. 1 from the main surface facing the wiring board. FIG. 3 is a schematic cross-sectional view when the crystal oscillator shown in FIG. 1 is assembled. 4 (a) to 4 (e) are explanatory views showing a schematic form of the structure of the present invention in each step in a cross-sectional view in order to explain each step in the manufacturing method of the present invention. FIG. 5 is a schematic sectional view showing an embodiment of a conventional piezoelectric oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wiring board 2 ... Integrated circuit element 3 ... Piezoelectric vibration element (crystal vibration element)
DESCRIPTION OF SYMBOLS 4 ... Lid 5 ... Conductive joining material 6 ... Electrode terminal for external connection 7 ... Electrode pad for piezoelectric vibration element mounting 9 ... Conductive pattern for sealing 10 ... Integrated circuit element Wafer 11 ... Electrode pad for substrate connection 12 ... Electrode pad for integrated circuit element connection 13 ... Sealing member 14 ... Space 15 ... Master substrate

Claims (2)

A piezoelectric vibration element;
An integrated circuit element including at least an oscillation circuit provided with an electrode pad for mounting the piezoelectric vibration element for mounting the piezoelectric vibration element;
A wiring board on which the integrated circuit element is mounted;
In the piezoelectric oscillator composed of the piezoelectric vibration element and the substantially box-shaped lid for hermetically sealing the integrated circuit element,
A space portion is formed between the integrated circuit element and the wiring board, and the electrode pad for mounting the piezoelectric vibration element is formed on the surface of the integrated circuit element facing the space portion, and the piezoelectric vibration element A piezoelectric oscillator characterized in that the piezoelectric vibration element is mounted on a mounting electrode pad. On an integrated circuit element wafer formed by connecting a plurality of integrated circuit element forming regions in which a substrate connection electrode pad and a piezoelectric vibration element mounting electrode pad are formed on one main surface in a matrix, each integrated circuit element A step A of mounting a piezoelectric vibration element on the electrode pad for mounting a piezoelectric vibration element in a formation region and forming a conductive bonding material on the electrode pad for substrate connection;
Cutting the integrated circuit element wafer on which the piezoelectric vibration element is mounted along the outer periphery of each integrated circuit element forming region to form individual integrated circuit elements on which the piezoelectric vibration element is mounted; and
The integrated circuit element on which the piezoelectric vibration element is mounted on a master substrate having a plurality of wiring board regions is directed toward the master substrate while holding the other main surface of the integrated circuit element. The integrated circuit element and the master substrate are individually arranged in each wiring board region in the form of the conductive bonding material so that the surface of the piezoelectric vibration element is not in contact with the surface of the master substrate and the surface of the integrated circuit element. Step C for secure connection;
A substantially box-shaped lid is covered in a form to cover each integrated circuit element on which the piezoelectric vibration element mounted on the master substrate is mounted, and the lid in which the integrated circuit element is built is hermetically sealed. Step D to be performed
A step E for cutting the master substrate along the outer periphery of the wiring board region to individually obtain a plurality of piezoelectric oscillators.

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