JP4899519B2 - Surface mount type piezoelectric oscillator - Google Patents

Description

  The present invention relates to a piezoelectric oscillator in which an integrated circuit element and a piezoelectric diaphragm are mounted on a ceramic base to constitute an oscillation circuit, and improves the package structure of a surface-mounted piezoelectric oscillator.

  As shown in Patent Document 1, a piezoelectric oscillator has a ceramic base housing portion in which a bank portion is formed and a metal lid on which a brazing material is formed. In general, the cover is hermetically sealed by welding. In recent years, portable electronic devices, such as mobile phones, are becoming lighter, thinner, and smaller. Along with this, a piezoelectric diaphragm having a further reduced size has been developed, and the piezoelectric oscillator has also been reduced in size. Some of such miniaturized piezoelectric diaphragms correspond to the characteristics of a specific circuit as compared with conventional piezoelectric diaphragms. Therefore, there is an increasing need to increase options by combining with a more compact piezoelectric diaphragm while using a conventional package, and to cope with various circuit characteristics.

In particular, miniaturized piezoelectric diaphragms that support higher frequencies are more extensive than conventional piezoelectric diaphragms, and integrated circuit elements are also matched with such compact and high-frequency piezoelectric diaphragms. There are a lot of things done. For this reason, use of a small piezoelectric diaphragm and integrated circuit for which high-frequency design has been completed in advance for a conventional package not only suppresses cost increase, but also provides a more reliable piezoelectric oscillator.
JP 2002-158558 A

  Japanese Patent Application Laid-Open No. 2004-133620 discloses mounting piezoelectric diaphragms of different sizes in one package, but it is impossible to mount a piezoelectric diaphragm of a size that does not contact both the holding base and the pillow portion. In other words, since the miniaturized piezoelectric diaphragm is mounted on a larger conventional package, the piezoelectric diaphragm is inclined and mounted below the holding base. For example, the package and the integrated circuit element are connected by a wire bonding method. In some cases, the wire may be damaged or cut due to the inclination of the piezoelectric diaphragm. In addition, when the miniaturized piezoelectric diaphragm is mounted inclined downward from the holding table, a pair of wiring patterns having different polarities formed on the holding table via the excitation electrode of the piezoelectric diaphragm are short-circuited. There is also a risk of destroying the integrated circuit element. Furthermore, when a miniaturized piezoelectric diaphragm is mounted in a larger conventional package, there are more gaps between the piezoelectric diaphragm and the package, and the electrode is used when adjusting the frequency by increasing or decreasing the mass of the excitation electrode of the piezoelectric diaphragm. A part of the material may adhere to the terminal portion of the integrated circuit element through the gap and adversely affect the characteristics.

  The present invention has been made in view of the above points, and an object of the present invention is to be able to mount piezoelectric diaphragms having different outer sizes, thereby eliminating the problem of inclination of the piezoelectric diaphragm and short-circuiting with the wiring pattern. It is another object of the present invention to provide a more reliable surface-mount piezoelectric oscillator that can suppress adverse effects during frequency adjustment.

  In order to achieve the above object, the present invention can be realized by the following configuration.

That is, in the present invention, a surface-mounted piezoelectric oscillator having an insulating base and a lid,
An integrated circuit element comprising a piezoelectric oscillation circuit and a piezoelectric diaphragm formed with excitation electrodes;
A first storage section that stores the integrated circuit element; a second storage section that stores the piezoelectric diaphragm above the first storage section; and a periphery of the first storage section and the second storage section An insulating base having a bank portion formed in
A lid formed on the insulating base and hermetically sealed;
In the second storage portion of the insulating base, an insulating holding base for holding one end of the piezoelectric diaphragm and a pillow portion are formed at a position facing the holding base via the first storage portion. A pair of wiring patterns for the piezoelectric diaphragm that are electrically and mechanically joined to the piezoelectric diaphragm are formed on the upper surface of the holding table;
The pair of wiring patterns includes a high wiring pattern portion in a region separated from the first storage portion of the holding base and a low wiring pattern portion in a region close to the first storage portion. An electrodeless portion is formed in a central region where each low wiring pattern portion is adjacent between the pair of low wiring pattern portions, and the pair of low wiring pattern portions are separated from each other on the bank portion side. It is formed in a biased way
A ridge portion adjacent to the first storage portion adjacent to the electrodeless portion of the holding table is configured as an insulating auxiliary holding portion.

  In addition to the above configuration, the pair of lower wiring pattern portions are formed with a narrow portion close to the high wiring pattern portion and a wide portion close to the first storage portion. And

  Further, in addition to the above configuration, the pair of wiring patterns is formed so that the height gradually decreases as the upper surfaces of the wiring patterns come closer to each other.

  According to the present invention, it is possible to mount piezoelectric diaphragms having different outer sizes on the pair of wiring patterns for the piezoelectric vibrator plate. At this time, the size of the piezoelectric storage plate that is larger than the first storage portion and that contacts both the holding base and the pillow portion can be suppressed by positioning the piezoelectric vibration plate on the pillow portion. Further, by disposing each of the pair of wiring patterns in the high wiring pattern portion and the low wiring pattern portion, it is possible to selectively mount piezoelectric diaphragms having different outer sizes. At this time, the piezoelectric diaphragm having a size larger than that of the first storage part corresponds to the dimension from the lower wiring pattern part to the pillow part, and corresponds to the dimension from the higher part wiring pattern part to the pillow part. Two types can be mounted, and the inclination can be suppressed by positioning each piezoelectric diaphragm on the pillow portion. For this reason, the integrated circuit element housed in the first housing part and the piezoelectric diaphragm do not come into contact with each other, and the terminal part and the wire of the integrated circuit element are not damaged. A short circuit between wiring patterns having different polarities does not cause destruction of the integrated circuit element.

In addition, the holding base is made of an insulating material, and between the pair of lower wiring pattern portions, an electrodeless portion is formed in a central region where each lower wiring pattern portion is adjacent, and the pair of lower wiring patterns Since the pattern portion is formed to be biased toward the bank portions separated from each other, and the ridge portion adjacent to the first storage portion adjacent to the non-electrode portion of the holding base is configured as an insulating auxiliary holding portion. One end of the piezoelectric diaphragm that is smaller in size than the first storage part and does not contact the pillow part can be mounted on the high wiring pattern part. Then, the pair of lower wiring pattern portions are not short-circuited with each other via the excitation electrode of the piezoelectric diaphragm, and the ridge portion adjacent to the first storage portion of the holding stand is not subjected to special processing. Available as Further, by mounting one end of the piezoelectric diaphragm that is smaller in size than the first storage part and does not contact the pillow part on the high wiring pattern part, the mass is increased or decreased with respect to the excitation electrode of the piezoelectric diaphragm. When the frequency adjustment is performed, the center portion of the excitation electrode can be shifted in a direction to be isolated from the first storage portion. Therefore, the electrode material is prevented from scattering through the gap with the piezoelectric diaphragm to the first storage portion, and as a result, the electrode material related to frequency adjustment does not adhere to the integrated circuit element, which adversely affects the characteristics. Never give.

  In addition, the pair of lower wiring pattern portions are formed with a narrow portion close to the high wiring pattern portion and a wide portion close to the first storage portion, so that the low wiring pattern portion is mounted on the low wiring pattern portion. It is easy to recognize the positional deviation of the piezoelectric diaphragm. Further, it is possible to suppress the conductive bonding material S applied to the lower wiring pattern portion from flowing out to the higher wiring pattern portion. For this reason, the bonding strength variation of the piezoelectric diaphragm is eliminated, and the excess conductive bonding material S does not wrap around the upper part of the piezoelectric diaphragm. Since the electrodes at the lead electrode portion and the low wiring pattern portion of the piezoelectric diaphragm mounted on the high wiring pattern portion can be prevented from facing each other, the influence of stray capacitance can be reduced.

  Further, since the pair of wiring patterns are formed so that the height gradually decreases as the upper surfaces of the mutual wiring patterns come close to each other, even if a piezoelectric diaphragm having a different size is mounted on the wiring pattern, the pair of wiring patterns A piezoelectric diaphragm is positioned between the wiring patterns. For this reason, the piezoelectric diaphragm can be stably mounted without being laterally displaced in the center of the holding table. In particular, when a piezoelectric diaphragm having a size smaller than that of the first storage part and not in contact with the pillow part is mounted on the high wiring pattern part, the piezoelectric diaphragm is not mounted on the bank side. The excitation electrode is positioned at the electrodeless portion between the lower wiring pattern portions, and there is no short circuit with the lower wiring pattern portion. Furthermore, if the size of the piezoelectric diaphragm is increased, the distance in the height direction from the integrated circuit element in the first housing portion can be increased, so that the large piezoelectric diaphragm having a high possibility of contact, The terminal part and the wire of the integrated circuit element are not damaged. A short circuit between wiring patterns having different polarities does not cause destruction of the integrated circuit element. In addition, since the wiring pattern and the ridge portion of the piezoelectric diaphragm are mounted in a line contact state, the conductive bonding material accumulates in the gap below the piezoelectric diaphragm, and the bonding strength can be improved.

  According to the present invention, a more reliable surface-mount type piezoelectric oscillator that can be mounted with piezoelectric diaphragms having different outer sizes, can eliminate the inclination of the piezoelectric diaphragm, and can suppress adverse effects when adjusting the frequency. It is to provide.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. A first embodiment of the present invention will be described with reference to FIGS. 1 to 3 by taking a surface-mounted crystal oscillator as an example. FIG. 1 is a plan view showing the first embodiment. 2A is a plan view of a state in which a large piezoelectric diaphragm is mounted on the ceramic base of FIG. 1, and FIG. 2B is a cross-sectional view taken along line AA of the plan view. 3A is a plan view of a state in which a small piezoelectric diaphragm is mounted on the ceramic base of FIG. 1, and FIG. 3B is a cross-sectional view taken along line BB of the plan view. The surface-mount type crystal oscillator is housed in a ceramic base (insulating base) 1 having a recess having an upper opening, an integrated circuit element 2 housed in the ceramic base, and the upper part in the ceramic base. The piezoelectric diaphragm 3 and a lid (not shown) joined to the opening of the ceramic base.

  The ceramic base 1 is a rectangular parallelepiped as a whole, and has a configuration in which a ceramic such as alumina and a conductive material such as tungsten are appropriately laminated, and has a concave storage portion 10 when viewed in cross section. The storage unit 10 includes a first storage unit 10a (lower storage unit) and a second storage unit 10b (upper storage unit), in which the piezoelectric diaphragm 3 and the integrated circuit element 2 are stored. A bank portion 11 is formed around the storage portion, and the top surface of the bank portion 11 is flat, and a circumferential first metal layer 11a (a sealing member) is formed on the bank portion. The upper surface of the first metal layer 11a is also formed to be flat, and the metal film layers are formed in the order of tungsten, nickel, and gold. Tungsten is formed integrally during ceramic firing by metallization technology using thick film printing technology, and each layer of nickel and gold is formed by plating technology.

  A plurality of castellations extending in the vertical direction are formed on the end portion on the ceramic base side. The castellation has a configuration in which arc-shaped cutouts are formed in the vertical direction. The first metal layer 11a is electrically derived to an external connection electrode (not shown) formed on the lower surface of the ceramic base by a conductive via (not shown) that vertically connects the corners of the ceramic base. Has been. By grounding the external lead electrode, a metal lid described later is grounded through the metal layer 11a and the conductive via, and an electromagnetic shielding effect of the electronic component can be obtained. As described above, the conductive via can be formed by a known ceramic lamination technique.

  Inside the ceramic base 1, on the lower surface, as described above, the first storage portion 10a for storing the integrated circuit element 2, the holding base 10c for holding one end of a piezoelectric diaphragm described later, and the first storage portion are provided. A pillow portion 10d is formed so as to face the holding table, and a second storage portion 10b is formed above the first storage portion 10a. A dummy pattern 14 that is not connected to an external terminal is formed on the upper surface of the pillow portion. On the upper surface of the holding table, wiring patterns 12 and 13 for the piezoelectric vibrator plate are formed side by side in the short side direction so as to be biased only in a region separated from the first storage portion 10a. For this reason, the edge part 101c adjacent to the 1st accommodating part of a holding stand can be utilized as an auxiliary | assistant holding | maintenance part, without giving a special process. The auxiliary holding portion 101c is set to have a height lower than the dummy pattern 14 and the wiring patterns 12 and 13 of the pillow portion 10d by the amount that the pattern is not formed.

  Each wiring pattern is led out as an input / output terminal to an external connection terminal electrode (not shown) formed on the lower surface of the ceramic base on the opposite surface by a conductive via. In addition, a plurality of wiring patterns 16a for the integrated circuit element 2 are formed side by side between the holding base and the pillow portion in the peripheral portion of the first storage portion 10a. The ceramic base having such a structure is formed by using a known ceramic lamination technique and metallization technique, and the wiring pattern is formed of a nickel plating layer and a gold plating layer on the upper surface of the metallization layer made of tungsten or the like, similar to the formation of the metal layer 11a described above. Is formed. The dummy pattern 14 has a structure in which only a metallized layer made of tungsten or the like is formed.

  The integrated circuit element 2 mounted in the lower housing part is a one-chip integrated circuit element that constitutes an oscillation circuit together with the piezoelectric diaphragm 3, and a plurality of connection terminals (not shown) are formed on the upper surface thereof. In the integrated circuit element 2, a plurality of connection terminals of the integrated circuit element and a plurality of connection pads 16a formed on the ceramic base are respectively connected by a wire bonding method.

  A piezoelectric diaphragm 3 is mounted above the integrated circuit element 2 with a predetermined interval. The piezoelectric diaphragm 3 is, for example, a rectangular AT-cut quartz diaphragm, a pair of rectangular excitation electrodes 31 and 32 (only 31 is shown) facing the front and back surfaces, and the excitation electrode on the outer periphery of the quartz diaphragm. Lead-out electrodes 33 and 34 are formed. Each of these electrodes can be formed by a thin film forming means such as a vacuum deposition method or a sputtering method.

  For bonding the piezoelectric diaphragm and the ceramic base, for example, an appropriate amount of conductive bonding material S is supplied to the upper surfaces of the wiring patterns 12 and 13 from the application nozzle of the dispenser. Thereafter, the piezoelectric diaphragm 2 is mounted on the wiring patterns 12 and 13. As a result, the lead electrode of the piezoelectric diaphragm and the wiring pattern are electrically and mechanically connected. However, if necessary, a conductive bonding material (not shown) is applied again to the lead electrode part of the mounted piezoelectric diaphragm. May be. The conductive bonding material S is in the form of a paste, and examples thereof include a silicone-based conductive resin adhesive containing metal fine pieces such as silver filler. In addition to the silicone-based adhesive, for example, urethane-based, imide-based, polyimide And epoxy conductive resin adhesives can be used.

  At this time, in FIG. 2, the size is larger than that of the first storage portion, and the piezoelectric diaphragm in contact with both the wiring patterns 12 and 13 of the holding base and the pillow portion 10 d is mounted on the ceramic base of the embodiment of the present invention. Is shown. By positioning the piezoelectric diaphragm 3 on the wiring patterns 12 and 13 and the dummy pattern 14 of the pillow part, the auxiliary holding part 101c and the piezoelectric diaphragm 3 are not in contact with each other, and the inclination of the piezoelectric diaphragm 3 is suppressed. Can do. FIG. 3 shows a state in which a piezoelectric diaphragm that is smaller in size than the first storage part and does not contact the pillow part 10d is mounted on the ceramic base of the embodiment of the present invention. By mounting one end of the piezoelectric diaphragm 3 on the wiring patterns 12 and 13, the inclination of the piezoelectric diaphragm 3 can be suppressed at the ridge portion 101 c close to the first storage portion of the holding base. As a result, the integrated circuit element housed in the first housing portion does not come into contact with the piezoelectric diaphragm, and the terminal portions and wires of the integrated circuit element are not damaged at all. Further, the auxiliary holding portion 101c is set to have a height lower than the dummy pattern 14 and the wiring patterns 12 and 13 of the pillow portion 10d by the amount of no pattern. For this reason, even when the piezoelectric diaphragm is mounted on the wiring patterns 12 and 13, a gap with the holding base 10c is secured, so that the characteristics of the piezoelectric diaphragm 3 may be deteriorated without impeding the vibration. Absent.

  The lid (not shown) that hermetically seals the ceramic base has a configuration in which a metal brazing material (sealing material) is formed on a core material made of, for example, Kovar. More specifically, for example, a nickel layer, A Kovar core material, a copper layer, and a silver brazing layer are arranged in this order, and the silver brazing layer is joined to the ceramic-based first metal layer. The external shape of the metal lid in plan view is substantially the same as or slightly smaller than that of the ceramic base.

  The integrated circuit element 2 and the piezoelectric diaphragm 3 are stored in the storage portion 10 of the ceramic base 1 and covered with the metal lid, and the sealing material for the metal lid and the sealing member for the ceramic base are melt-cured and hermetically sealed. Stop. In this embodiment, airtight sealing is performed by seam welding without using a metal ring for sealing, and the seam roller runs along the ridges of the long side and the short side of the metal lid, The silver brazing (sealing material) formed on the lid and the first metal layer 11a (sealing member) of the ceramic base 1 are welded to perform hermetic sealing.

  Next, a second embodiment of the present invention will be described with reference to FIGS. 4 to 7 by taking a surface mount type crystal oscillator as an example. FIG. 4 is a plan view showing the second embodiment. FIG. 5A is a plan view of a state in which a large piezoelectric diaphragm is mounted on the ceramic base of FIG. 4, and FIG. 5B is a cross-sectional view taken along line CC of the plan view. 6 is a plan view (a) of a state in which a medium-sized piezoelectric diaphragm is mounted on the ceramic base of FIG. 4, and a cross-sectional view (b) along the line DD of the plan view. 7 is a plan view (a) of a state in which a small piezoelectric diaphragm is mounted on the ceramic base of FIG. 4, and a cross-sectional view (b) along the line EE of the plan view. Since the basic configuration is the same as that of the first embodiment, the same reference numerals are used for the same components, and a part of the description is omitted.

  Inside the ceramic base 1, on the lower surface, as described above, the first storage portion 10a (lower storage portion) that stores the integrated circuit element 2, the holding base 10c that holds one end of a piezoelectric diaphragm described later, and the first A pillow portion 10d is formed so as to face the holding table via one storage portion, and a second storage portion 10b (upper storage portion) is formed above the first storage portion 10a. Yes. A dummy pattern 14 that is not connected to an external terminal is formed on the upper surface of the pillow portion. On the upper surface of the holding table, wiring patterns 12 and 13 for the piezoelectric vibrator plate are formed side by side in the short side direction. The wiring patterns 12 and 13 are divided into a high wiring pattern portion 121 and 131 in a region separated from the first storage portion 10a, and a low wiring pattern portion 122 and 131 in a region close to the first storage portion 10a. In the lower wiring pattern portion, electrodeless portions 123 and 133 are formed in the central region where the wiring patterns are close to each other.

  For this reason, it is possible to mount piezoelectric diaphragms having different outer sizes by disposing the high wiring pattern portions 121 and 131 and the low wiring pattern portions 122 and 132, respectively. At this time, as shown in FIG. 5 and FIG. 6, the piezoelectric diaphragm 3 that is larger in size than the first storage part and is in contact with both the wiring patterns 12 and 13 of the holding base and the pillow part 10 d has a high wiring pattern. Two types can be mounted: a large one corresponding to the dimension from the part 121, 131 to the dummy pattern 14 of the pillow part, and a medium type corresponding to the dimension from the low part wiring pattern part 122, 132 to the pillow part 10d, And inclination can be suppressed by positioning each piezoelectric diaphragm in a pillow part.

  In addition, the holding base 10d is made of an insulating material, and electrodeless parts 123 and 133 are formed between the pair of lower wiring pattern parts 122 and 132, and the pair of lower wiring pattern parts 122 and 132 are It is formed so as to be biased toward the bank portions that are separated from each other. At this time, the electrodeless portions 123 and 133 are formed larger than the excitation electrode of the small piezoelectric diaphragm to be mounted, and dimension adjustment is required according to the dimensions of the excitation electrode of the small piezoelectric diaphragm to be mounted. . For this reason, as shown in FIG. 7, one end of the piezoelectric diaphragm 3 which is smaller in size than the first storage part and does not contact the pillow part 10d can be mounted on the high wiring pattern parts 121 and 131. Since the ridge portion 101c adjacent to the first storage portion of the holding base can be used as an auxiliary holding portion without short-circuiting with the lower wiring pattern portions 122 and 132 and without performing special processing, the piezoelectric diaphragm 3 Can be suppressed. As a result, the integrated circuit element housed in the first housing portion does not come into contact with the piezoelectric diaphragm, and the terminal portions and wires of the integrated circuit element are not damaged at all. The lower wiring pattern portions 122 and 132 having different polarities are not short-circuited with each other via the excitation electrode 32 on the bottom surface side of the piezoelectric diaphragm, and the integrated circuit element is never destroyed. In addition, by mounting one end of the piezoelectric diaphragm 3 smaller in size than the first storage part and not in contact with the pillow part on the high wiring pattern parts 121 and 131, the excitation electrode 31 of the piezoelectric diaphragm is mounted. When adjusting the frequency to increase / decrease the mass, the central portion of the excitation electrode 31 can be shifted in a direction to be isolated from the first storage portion 10a. Accordingly, the electrode material is prevented from scattering through the gap with the piezoelectric diaphragm to the lower housing portion 10a, and as a result, the electrode material related to frequency adjustment is not attached to the integrated circuit element 2 and the characteristics are adversely affected. Never give.

  Each of these wiring patterns 12 and 13 is made of metallization such as tungsten, and by using a thick film printing technique, the low wiring pattern portions 122 and 132 and the high wiring pattern portions 121 and 131 can be made extremely easy. Can be created. For example, a single-layer metallization is formed for the whole of the lower wiring pattern portions 122 and 132 and the higher wiring pattern portions 121 and 131, and the region of the higher wiring pattern portions 121 and 131 is formed on the upper surface of the metallization. Further, metallized bumps are formed by laminating one or more metallized layers. The height of these metallizations can be adjusted very easily by changing the number of laminations. With this configuration, the auxiliary holding portion 101c which is the electrodeless portions 123 and 133 is the lowest, the lower wiring pattern portions 122 and 132 are next lower, and the higher wiring pattern portions 121 and 131 are the highest. It is comprised so that it may become. The dummy pattern 14 of the pillow portion 10d is set to the same height as the high wiring pattern portions 121 and 131. As described above, even when the piezoelectric diaphragm is mounted on the wiring patterns 12 and 13, a gap with the holding base 10c is ensured, so that the characteristics of the piezoelectric diaphragm 3 are deteriorated without impeding the vibration. Nor.

  The low wiring pattern portions 122 and 132 are formed with narrow portions 124 and 134 that are close to the high wiring pattern portion and wide portions 125 and 135 that are close to the first storage portion. For this reason, the positional deviation of the piezoelectric diaphragm 3 mounted on the lower wiring pattern portions 122 and 132 can be easily recognized. It is possible to suppress the conductive bonding material S applied to the low wiring pattern portions 122 and 132 from flowing out to the high wiring pattern portions 121 and 131. For this reason, the bonding strength variation of the piezoelectric diaphragm is eliminated, and the excess conductive bonding material S does not wrap around the upper part of the piezoelectric diaphragm. Since the lead-out electrodes 33 and 34 of the piezoelectric diaphragm 3 mounted on the high wiring pattern portions 121 and 131 and the low wiring pattern portions 122 and 132 are avoided from facing each other, The effect of stray capacitance can be reduced.

  The integrated circuit element 2 and the piezoelectric diaphragm 3 are housed in the housing portion 10 of the ceramic base 1 and covered with the metal lid, and the silver solder (sealing material) of the metal lid and the first metal layer 11a of the ceramic base ( The sealing member is melt-cured and hermetically sealed by seam welding.

  A modification of the above embodiment will be described with reference to FIGS. FIG. 8 is a plan view (a) showing a first modification of the ceramic base of FIG. 4, a cross-sectional view (b) along the line FF of the plan view, and a line GG of the plan view. It is sectional drawing (c) along. 9 is a plan view (a) showing a second modification of the ceramic base of FIG. 4, a cross-sectional view (b) along the line HH of the plan view, and a line II of the plan view. It is sectional drawing (c) along. Since the basic configuration is the same as that of the second embodiment, the same reference numerals are used for the same components, and only the differences will be described.

  In FIG. 8, the height of the holding base 10c is constant, and only the upper surfaces of the wiring patterns 12 and 13 are formed to be inclined so that the height gradually decreases as they approach each other. In FIG. 9, the thickness of the wiring patterns 12 and 13 is constant, and the upper surface of the upper holding table 10 c is inclined so that the height gradually decreases as the wiring patterns 12 and 13 approach each other. The method of providing the inclination in the wiring pattern is, for example, that the thickness is gradually reduced as the wiring pattern is formed by thick film printing, or the thickness is gradually increased as the wiring pattern is approached. Metal etching is preferably performed so as to be thin. For example, when the ceramic base is laminated, the holding base is inclined so that the height decreases in a fine step shape as the wiring pattern approaches, or the height gradually decreases as the wiring pattern approaches. This can be achieved by using a mold and pressing. In these modified examples, the pair of wiring patterns 12 and 13 are arranged so that the height gradually decreases as the wiring patterns come closer to each other. Even if the piezoelectric diaphragm 3 is mounted, the piezoelectric diaphragm 3 is positioned between the pair of wiring patterns 12 and 13. For this reason, the piezoelectric diaphragm 3 can be stably mounted without laterally shifting to the center of the holding table 10c. In particular, when the piezoelectric diaphragm 3 that is smaller in size than the first storage part and is not in contact with the pillow part 10d is mounted on the high wiring pattern parts 121 and 131, the excitation electrode 32 of the piezoelectric vibration plate is the low wiring pattern part. Positioned at the non-electrode portions 125 and 135 between 122 and 132, there is no short circuit with the lower wiring pattern portions 122 and 132. Further, if the size of the piezoelectric diaphragm 3 is increased, the distance in the height direction from the integrated circuit element 2 in the first housing portion can be increased, so that a large piezoelectric diaphragm having a high possibility of contact. The terminal 3 and the wire of the integrated circuit element 2 are not damaged by 3. A short circuit between wiring patterns having different polarities does not cause destruction of the integrated circuit element. In addition, since the wiring patterns 12 and 13 and the ridges of the piezoelectric diaphragm 3 are mounted in a line contact state, the conductive bonding material S accumulates in the lower gap of the piezoelectric diaphragm 3 to improve the bonding strength. Can do. It is also possible to combine the configurations of FIGS.

  In the first embodiment and the second embodiment, hermetic sealing by seam welding without using a metal ring for sealing is taken as an example, but a metal ring for sealing may be used, and laser Further, beam sealing such as electron beam or glass sealing using glass as a sealing material may be used. The conductive bonding material used for bonding the piezoelectric diaphragm and the ceramic base is not limited to the resin adhesive, and may be a plating bump, a metal bump, a metal brazing material, or the like. Furthermore, the electrical connection between the integrated circuit element and the ceramic base is not limited to the wire bonding method, and a flip chip bonding method or the like may be employed.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof, and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not limited by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

It is a top view which shows 1st Embodiment. FIG. 2A is a plan view of a state in which a large piezoelectric diaphragm is mounted on the ceramic base of FIG. 1 and a cross-sectional view taken along line AA of the plan view. FIG. 2 is a plan view (a) of a state in which a small piezoelectric diaphragm is mounted on the ceramic base of FIG. 1 and a cross-sectional view (b) along the line BB of the plan view. It is a top view which shows 2nd Embodiment. FIG. 5A is a plan view of a state in which a large piezoelectric diaphragm is mounted on the ceramic base of FIG. 4, and FIG. 5B is a cross-sectional view taken along line CC of the plan view. FIG. 5A is a plan view of a state in which a medium-sized piezoelectric diaphragm is mounted on the ceramic base of FIG. 4 and a cross-sectional view taken along line DD of the plan view. FIG. 5A is a plan view of a state in which a small piezoelectric diaphragm is mounted on the ceramic base of FIG. 4, and FIG. 5B is a cross-sectional view taken along line EE of the plan view. The top view (a) which shows the 1st modification of the form of the ceramic base of FIG. 4, sectional drawing (b) along the FF line of the top view, and along the GG line of the top view It is a sectional view (c). The top view (a) which shows the 2nd modification of the form of the ceramic base of FIG. 4, sectional drawing (b) along the HH line of the top view, and along the II line of the top view It is a sectional view (c).

DESCRIPTION OF SYMBOLS 1 Ceramic base 2 Integrated circuit element 3 Piezoelectric diaphragm S Conductive joining material

Claims (3)

A surface mount piezoelectric oscillator having an insulating base and a lid,
An integrated circuit element comprising a piezoelectric oscillation circuit and a piezoelectric diaphragm formed with excitation electrodes;
A first storage section that stores the integrated circuit element; a second storage section that stores the piezoelectric diaphragm above the first storage section; and a periphery of the first storage section and the second storage section An insulating base having a bank portion formed in
A lid formed on the insulating base and hermetically sealed;
In the second storage portion of the insulating base, an insulating holding base for holding one end of the piezoelectric diaphragm and a pillow portion are formed at a position facing the holding base via the first storage portion. A pair of wiring patterns for the piezoelectric diaphragm that are electrically and mechanically joined to the piezoelectric diaphragm are formed on the upper surface of the holding table;
The pair of wiring patterns includes a high wiring pattern portion in a region separated from the first storage portion of the holding base and a low wiring pattern portion in a region close to the first storage portion. An electrodeless portion is formed in a central region where each low wiring pattern portion is adjacent between the pair of low wiring pattern portions, and the pair of low wiring pattern portions are separated from each other on the bank portion side. It is formed in a biased way
A surface-mount type piezoelectric oscillator characterized in that an edge portion adjacent to the first storage portion adjacent to the electrodeless portion of the holding base is configured as an insulating auxiliary holding portion. The pair of low part wiring pattern parts are formed with a narrow part close to the high part wiring pattern part and a wide part close to the first storage part. Surface mount type piezoelectric oscillator. 3. The surface-mount type piezoelectric device according to claim 1, wherein the pair of wiring patterns are formed such that the height gradually decreases as the upper surfaces of the wiring patterns come closer to each other. Oscillator.

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