JP2013140875A - Electronic device and manufacturing method thereof, piezoelectric oscillator, and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, when a peripheral portion of a metal lid is fused on an electroless nickel film formed on an insulating substrate by irradiating laser light thereon, the fused range of the electroless nickel film expands beyond the bottom area of the peripheral portion of the metal lid, part of which is exposed to the inside of a cavity, causing gas to develop.SOLUTION: In an electronic device, a solder material layer 19B and an electroless nickel film 15 are fused by irradiating laser light from a metal lid 19 side across the electroless nickel film to join an insulating substrate 11 and the metal lid together. The electronic device is provided with a covering solder material region 36 which is formed by solidifying part of the other section of the solder material layer after being fused in order to cover an inside fused portion 15b of the electroless nickel film extending to the inside beyond a directly joined region 35 between the electroless nickel film and the peripheral portion of the metal lid.

Description

  The present invention relates to an electronic device in which a metal lid is bonded by locally heating the ceramic substrate to which the electronic component is bonded using laser light or the like to seal the electronic component, a method for manufacturing the electronic device, a piezoelectric oscillator, It relates to electronic equipment.

Conventionally, an electronic device for surface mounting in which an electronic component bonded to a ceramic substrate is sealed with a metal lid has been widely used. For example, as a clock source for electronic circuits of various electronic devices such as OA equipment such as information communication equipment and computers, consumer equipment, etc., a piezoelectric vibrating piece as an electronic component is joined to a ceramic substrate and the piezoelectric vibrating piece is covered. 2. Description of the Related Art Piezoelectric devices are widely used as electronic devices in which a piezoelectric vibrating piece is hermetically sealed in a concave space formed by a ceramic substrate and a metal lid by joining a concave metal lid on the ceramic substrate.
In general, when joining a metal lid and a ceramic (alumina) substrate by laser light or electron beam irradiation, the peripheral portion of the metal lid is placed on a metallized layer formed in advance on the ceramic substrate side via a brazing material. Laser welding or the like is irradiated from above the peripheral edge of the metal lid in a stacked state, and welding is performed by melting and solidifying the brazing material.
Patent Document 1 (Japanese Patent Application Laid-Open No. 11-126850) discloses a surface of a metal lid in a hermetic sealing structure of an electronic device in which a brazing material is heated and melted by electron beam irradiation to join a ceramic substrate and the metal lid. A part of the corrosion-resistant nickel layer previously laminated by electrolytic plating or electroless plating is made to function as a brazing material. For this reason, it is said that the problem of deterioration in airtightness due to oxidative corrosion of silver brazing, which is a problem when silver brazing is used as the brazing material, can be solved, and the electronic component can function stably for a long period of time.

Japanese Patent Laid-Open No. 11-126850

However, a high purity nickel layer formed by electrolytic plating has a melting point of 1450 degrees, and even if a silver wax having a melting point of about 780 ° C. is melted, the nickel layer does not melt, so the nickel layer is melted together with the silver solder. It is impossible to use it as a brazing material.
Further, when the nickel layer is formed by electroless plating, phosphorus (P) is taken into the nickel layer, so that gas is released from the nickel portion into the metal lid body, and the electronic component functions stably. I can't. In the case of a crystal resonator, there is a problem that frequency characteristics and impedance change due to aging.

FIGS. 8A and 8B are a longitudinal sectional view of an electronic device (quartz crystal unit) in which a cap-shaped metal lid 110 is joined on a ceramic substrate 100, and an enlarged sectional view of the joined portion.
This electronic device has a ceramic substrate 100, a piezoelectric vibrating piece 110 bonded on one main surface (upper surface) of the ceramic substrate 100, and a peripheral portion bonded onto the ceramic substrate 100 so as to cover the piezoelectric vibrating piece 110. The piezoelectric vibrating piece 110 is hermetically sealed in a cavity T formed by the ceramic substrate 100 and the metal lid 120.
The ceramic substrate 100 includes a flat ceramic base material (insulating base material) 101 made of alumina, a vibration piece bonding terminal 102 to which a piezoelectric vibration piece formed on the upper surface is bonded, and a metallized layer for bonding a metal lid. 103 and a plurality of external mounting terminals 104 formed on the lower surface of the ceramic substrate.
The metallized layer 103 includes a wiring material 105 such as copper formed on the ceramic substrate 101 and an electroless nickel film 106 formed by electroless plating so as to cover the surface of the wiring material. The electroless nickel film contains phosphorus.
The metal lid 120 has a configuration in which a silver brazing film 120B is laminated on the lower surface of a base material 120A such as Kovar, and a nickel film 120A is laminated on the surface. Further, the metal lid 120 has a horizontal portion 120a in the central portion, is bent at an obtuse angle on the outer peripheral side of the horizontal portion 120a to form a side wall portion 120b, and further horizontally extends from the side wall portion 120b to the outer peripheral side. The contact leg portion 120c is formed by being bent.

As shown in FIG. 8B, the silver brazing film 120B on the lower surface of the contact leg portion is irradiated with laser light to the contact leg portion (joint portion) 120a of the metal lid body 120, and there is no blank. When the electrolytic nickel film 106 is melted and then solidified, the wiring material 105 and the contact leg can be joined.
However, the melting range 106a of the electroless nickel layer 106 that is melted by the irradiation of the laser light extends inward and outward beyond the bottom area of the contact leg portion 120c, and a part 106b is exposed inside the cavity T. Become.
Since the gas containing the phosphorus component contained in the electroless nickel film leaks into the cavity T from the melting range 106b on the inner side, the above-described problems occur.

  The present invention relates to a melting range of an electroless nickel film when the peripheral part of a metal lid having a brazing material film on the lower surface is melted by laser light irradiation on an electroless nickel film formed on an insulating substrate. The purpose of this is to eliminate the problem that the gas expands inward and outward beyond the bottom area of the peripheral edge of the metal lid, and a part of it is exposed to the inside of the cavity and causes gas generation. .

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 An electronic device according to this application example includes an insulating substrate provided with a metallized layer including an electroless nickel film, an electronic component bonded on one surface of the insulating substrate, and a surface including a peripheral portion. A metal lid that joins the peripheral portion to the metallized layer with the brazing material to form an internal space for housing the electronic component, and is provided in the internal space. The electrolytic nickel film is covered with a brazing material.

  According to the piezoelectric device of this application example, the inner melting site is completely covered by the coating brazing material region formed by partially melting and flowing down the silver brazing film formed on the metal lid. Generation of gas from the inner melting site can be prevented.

  Application Example 2 In the insulating base material, one surface where the electronic components are joined is a flat surface, and the metal lid has a recess for forming the internal space.

  Although there are various types of electronic device packages, the present invention can be applied to a type in which the insulating base surface is flat and the metal lid is inverted.

  Application Example 3 The metallization layer is characterized by being composed of copper and the electroless nickel film covering the outer surface of the copper.

  Since the electroless nickel film can be used as a brazing material, the airtightness of the joint can be improved without increasing the film thickness of the silver brazing film on the metal lid side.

  Application Example 4 The method of manufacturing an electronic device according to any one of Application Examples 1 to 3, wherein the electronic component, the insulating substrate, and the metal lid are prepared, and the insulating substrate. A step of bonding the electronic component thereon, a step of disposing the metal lid on the insulating substrate, and irradiating heating light or an electron beam on the inner side of the peripheral portion to the inner space. And melting a certain brazing material.

  According to this application example, the inner melting part is completely covered by the coating brazing material region formed by partially melting and flowing down the silver brazing film formed on the metal lid, so that the inner melting part The generation of gas from can be prevented.

  [Application Example 5] The step of melting the brazing material in the internal space and the step of joining the lid are performed simultaneously.

  You may implement a joining process by one laser irradiation.

  [Application Example 6] The piezoelectric device according to any one of Application Examples 1 to 3 is a piezoelectric vibrator and includes a semiconductor element.

  The present invention can also be applied to a piezoelectric oscillator.

  Application Example 7 An electronic apparatus including the electronic device according to any one of Application Examples 1 to 3.

  The present invention can also be applied to electronic devices.

It is a top view of one embodiment of a piezoelectric device as an example of an electronic device of the present invention. (A) is the partial cross section top view which looked at the piezoelectric device from the upper side, (b) is the longitudinal cross-sectional view along the AA line of (a). (A) And (b) is a fragmentary sectional view which expands and demonstrates a part (joining part) of FIG.2 (b) in detail. (A) (b) And (c) is the longitudinal cross-sectional view of the piezoelectric device as an example of the electronic device which concerns on other embodiment of this invention, and the principal part enlarged view. It is a flowchart which shows an example of the manufacturing method of the piezoelectric device which concerns on this invention. It is a top view which shows the process in which a ceramic substrate is manufactured with a green sheet. It is sectional drawing which shows the structural example which applied the package junction structure of this invention to the piezoelectric oscillator. (A) And (b) is a longitudinal cross-sectional view of the electronic device (quartz crystal unit) which joined the cap-shaped metal cover body on the ceramic substrate, and the expanded sectional view of the junction part. It is a schematic block diagram which shows the structure of the electronic device which concerns on this invention.

Preferred embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a plan view of an embodiment of a piezoelectric device as an example of an electronic device of the present invention, FIG. 2 (a) is a partial sectional plan view of the piezoelectric device as viewed from above, and FIG. It is a longitudinal cross-sectional view along the AA line. In FIG. 2A, for convenience of explanation of the internal structure of the piezoelectric device, a part of the metal lid (19) provided above the piezoelectric device is cut out. FIGS. 3A and 3B are partial cross-sectional views illustrating in detail a part (joint portion) of FIG.

1 and 2, a piezoelectric device 1 includes a ceramic substrate 10 as an insulating substrate, a piezoelectric vibrating piece 20 as an electronic component joined on one main surface (upper surface) of the ceramic substrate 10, and a piezoelectric vibrating piece. A concave metal lid 19 joined to the ceramic substrate 10 so as to cover the ceramic substrate 10, and the piezoelectric vibrating reed 20 is hermetically sealed in a cavity T formed by the ceramic substrate 10 and the metal lid 19. It has been stopped.
The ceramic substrate 10 and the metal lid 19 constitute a package.
The ceramic substrate 10 has a resonator element bonding terminal 18 to which the piezoelectric resonator element 20 is bonded to one main surface (upper surface) of a flat ceramic substrate (insulating substrate) 11 made of alumina, and the other main surface. A plurality of external mounting terminals 16 are provided on the (lower surface). The resonator element joining terminal 18 and other terminals (not shown) are formed in a layer wiring (via) 17 formed by embedding a conductive paste containing a refractory metal in a through hole (via hole) provided in the ceramic substrate 11. To the corresponding external mounting terminal 16.

One main surface of the ceramic substrate 10 provided with the external mounting terminals 16 serves as an outer bottom surface of the piezoelectric device 1, and the external mounting terminals 16 provided on the outer bottom surface make the piezoelectric device 1 an external mounting substrate such as an electronic device. Can be implemented. The ceramic substrate 11 constituting the ceramic substrate 10 of the present embodiment is formed by forming and processing a green sheet and firing it.
The piezoelectric vibrating piece 20 has a configuration in which excitation electrodes 25 as counter electrodes are provided on both main surfaces of a flat plate-like piezoelectric substrate made of a piezoelectric material such as quartz. Further, an external connection electrode 26 is provided on one end side of each main surface of the piezoelectric vibrating piece 20, and each is electrically connected by an inter-electrode wiring drawn from the corresponding excitation electrode 25. In addition, as a material of the piezoelectric vibrating piece 20, examples of the piezoelectric material other than quartz include lithium tantalate and lithium niobate, and examples of materials other than the piezoelectric material include silicon. On the ceramic substrate 10 (the other main surface side), the piezoelectric vibrating piece 20 is in a state where the external connection electrode 26 provided on one end side thereof is aligned with the corresponding vibrating piece joining terminal 18 of the ceramic substrate 10, for example. They are joined together while being electrically connected by a joining member 30 such as silver paste, and are cantilevered with the other end as a free end.

The metal lid 19 hermetically seals the mounting area of the piezoelectric vibrating piece 20 by accommodating the piezoelectric vibrating piece 20 in the cavity T surrounded by the recess and the bonding surface of the piezoelectric vibrating piece 20 of the ceramic substrate 10. Is for.
The concave metal lid 19 is formed by forming a plate material made of a metal such as Kovar, 42 alloy, or phosphor bronze by a conventionally well-known sheet metal working, and has a concave portion (internal space) formed on the lower surface of the central portion. Has a ring-shaped contact leg portion 19c. That is, the metal lid body 19 has a horizontal portion 19a at the center, a side wall portion 19b extending downward from the outer peripheral side of the horizontal portion 19a to the oblique outer side is formed, and a lower edge portion of the side wall portion 19b is further formed. By bending toward the outer peripheral side, an annular contact leg portion 19 c substantially parallel to the horizontal portion 19 a is formed on the outer peripheral portion of the metal lid 19.
The metal lid 19 is in contact with a base material 19A made of Kovar (linear expansion coefficient: 5.5 ppm / ° C.), which is a metal material having a linear expansion coefficient close to that of the ceramic substrate (7 ppm / ° C.). A silver brazing film 19B as a brazing material laminated on the lower surface of the base material including the leg portion 19c by the cladding method, and a nickel film 19C as an antioxidant film laminated on the upper surface of the base material 19A by the cladding method Has been.
As the material of the base material 19A, 42 nickel and SUS can be used except for Kovar.

As shown in FIG. 3, a metallized layer 13 made of the same material as that of the resonator element joining terminal 18 is formed on the outer peripheral upper surface 12 of the ceramic substrate 10 to which the lower surface of the contact leg 19 c is bonded.
The metal lid 19 has the contact leg 19c facing the metallized layer 13 of the ceramic substrate 10 with the opening side of the recess formed by the horizontal portion 19a and the side wall portion 19b facing the ceramic substrate 10 side. Let them join.
The metallized layer 13 is composed of a wiring material 14 such as copper laminated on a ceramic base material, and an electroless nickel film 15 laminated and formed by electroless plating to cover the outer surface of the wiring material 14. Yes.
As shown in FIG. 3, the silver brazing film 19B and the electroless nickel layer 15 are formed by irradiating a laser beam or an electron beam from the contact leg 19c side of the metal lid with the metallized layer 13 interposed therebetween. At the same time, the insulating base and the metal lid can be joined by melting.
In the above-described embodiment, the electroless nickel film 15 is laminated on the outer surface of the wiring material 14 such as copper as the metallized film 13, but the electroless nickel film is directly formed on the ceramic substrate as the wiring material. It is good also as a structure.
The present invention has an insulating substrate 10 provided with a metallized layer 13 including an electroless nickel film, an electronic component 20 bonded on one surface of the insulating substrate, and a brazing material layer on one surface including a peripheral portion, A metal lid that joins the metallization layer with a brazing material to form an internal space (not included in the joint) that accommodates electronic components, and the electroless nickel film in the internal space is brazed. The point covered with the material is characteristic.

In the present embodiment, a configuration example in which an electroless nickel film is directly formed on a wiring material 14 formed on a ceramic substrate will be described.
In this embodiment, as shown in FIGS. 2 and 3, the metallized layer 13 on the upper surface of the ceramic substrate 10 and the lower surface of the contact leg 19 c of the metal lid 19 are made of, for example, a relatively low melting point alloy. It joins via the silver brazing film 19B as a joining member.
The metal lid 19 is preferably electrically connected to a ground terminal (not shown) of the ceramic substrate 10 through the metallized layer 13. In this way, when the piezoelectric device 1 is used, the metal lid body 19 made of metal is held at the ground potential, so that the piezoelectric vibrating piece 20 can be electrically connected to the outside due to the shielding effect of the metal lid body 19. It is possible to protect from effects such as noise.
Thus, the piezoelectric device 1 described above applies a variable voltage from the outside between the excitation electrodes 25 provided on both main surfaces of the piezoelectric vibrating piece 20 via the external mounting terminals 16 provided on the bottom surface of the ceramic substrate 10. It functions as the piezoelectric device 1 by causing vibration at a predetermined frequency according to the characteristics of the piezoelectric vibrating piece 20, and oscillates and outputs a reference signal having a predetermined frequency by an external oscillation circuit based on the resonance frequency of the piezoelectric device 1. can do. Such a reference signal can be used as a clock signal in an electronic device such as a portable communication device.

  Incidentally, the silver brazing film 19B is made of silver and copper as is well known, and has a melting point of about 700 to 800 degrees. On the other hand, electroless nickel as the material of the surface layer portion of the metallized layer 13 also has a melting point close to that of silver solder. For this reason, when the silver solder 19B is melted by irradiating the laser beam, the electroless nickel constituting the metallized layer located at the irradiated site is also melted and contributes to the bonding. In this manner, the contact leg 19c and the ceramic substrate can be hermetically joined by the cooperation of the silver brazing provided on the metal lid side and the electroless nickel film provided on the ceramic substrate side. Since silver solder is expensive, by using the electroless nickel film 15 as a brazing material, the amount of silver solder used can be reduced and the price of the metal lid can be reduced.

By the way, when the electroless nickel film 15 is used as a part of the metallized layer 13 in this way, it has been confirmed that a gas composed of a phosphorus (P) component is released from the molten nickel portion by laser light irradiation. ing. This is because phosphorus must be mixed when producing a nickel film by electroless plating. When this gas is discharged into the cavity T formed between the ceramic substrate and the metal lid, if the electronic device is a crystal resonator, the frequency characteristics and impedance due to aging change. Cause problems.
As shown in FIG. 3B, the characteristic configuration of the piezoelectric device 1 of the present invention that solves such a problem is that the electroless nickel film 15 and the peripheral edge portion (contact leg portion) of the metal lid body. A coating formed by melting and solidifying another part of the silver brazing film 19B in order to cover the inner melting portion 15b of the electroless nickel film extending to the inside of the cavity T beyond the bonding region 35 to be directly bonded The brazing material region 36 is provided.
The direct bonding region 35 is a region corresponding to the range of the electroless nickel film corresponding to the area of the lower surface of the contact leg portion 19c, and is used for heating light, for example, laser light 1, halogen lamp light, or electron beam. When the upper surface of the contact leg 19c is irradiated as shown in FIG. 3A, the range 15a where the electroless nickel film melts beyond the direct joining region 35 is expanded. A portion (inner melting portion) 15b located on the inner side of the metal lid in the electroless nickel film range 15a that melts beyond the direct joining region 35 serves as a source of gas composed of a phosphorus component and is contained in the cavity T. The generated gas causes deterioration of the characteristics of the electronic component.

In the present invention, in order to cope with such a problem, as shown in FIG. 3B, it is laminated on the back surface of the side wall portion 19b closer to the inner side than the silver brazing film 19B ′ laminated on the back surface of the contact leg portion 19c. In addition, a part of the silver brazing film 19B ″ was melted, and the silver wax whose fluidity was increased by melting was caused to flow down on the inner melting part 13b to completely cover the inner melting part 13b.
In order to melt the silver brazing film 19B ″ in this way, for example, after the laser beam 1 is irradiated as shown in (a), the laser beam 2 is applied to the side wall portion 19b as shown in (b). Irradiate the outer surface to melt a sufficient amount of silver wax to cover the inner melting portion 13b.
Alternatively, the spot diameter of the laser beam may be increased and the outer surfaces of the contact leg portion 19c and the side wall portion 19b may be simultaneously heated by a single irradiation to melt the silver braze laminated on the respective back surfaces. .

  In the piezoelectric device 1 of the present embodiment, the surface of the wiring material 14 to be joined to the metal lid 19 is covered with the electroless ceramic film 15 having a melting point equivalent to that of silver brazing. It can cooperate and contribute to joining, and the amount of expensive silver solder used can be reduced. In other words, the surface of the ceramic substrate formed by firing the green sheet is inherently formed with minute irregularities, and when the wiring material is formed on the irregularities, the irregularities are reflected on the wiring material surface. Is formed. Further, since the metal lid is a cap formed by drawing a thin metal plate, there are warps in various places. When such a metal lid is bonded to the surface of the wiring material and the silver brazing film 19B on the metal lid side is melted and bonded, defective melting and poor adhesion are likely to occur due to unevenness and warpage. In order to solve such a problem, it is effective to make the silver brazing film 19B on the metal lid side thick. However, since the silver brazing is expensive, the cost of the metal lid is increased. In the present invention, since the electroless nickel film 15 coated on the wiring material 14 can be used as a brazing material, the airtightness of the joint can be increased without increasing the film thickness of the silver brazing film 19B on the metal lid side. Can be increased.

Instead of the electroless nickel film, an electroless palladium film (Pd-P) may be used, and the electroless palladium can function as a brazing material in the same manner as the electroless nickel.
Further, when the contact leg 19c is bonded to the electroless ceramic film 15 by irradiating the laser beam, the melting range of the electroless nickel film is expanded on the inner side of the cavity T, and the inner melting exposed in the cavity. The portion 15b is formed, but the coated brazing material region 36 formed by partially melting and flowing down the silver brazing film 19B "formed inside the side wall portion 19b rising from the inner end portion of the contact leg portion. Thus, the inner melted portion 15b is completely covered, so that generation of gas from the inner melted portion can be prevented.

Next, FIGS. 4A, 4 </ b> B, and 4 </ b> C are a longitudinal sectional view and an enlarged view of a main part of a piezoelectric device as an example of an electronic device according to another embodiment of the present invention.
The piezoelectric device 40 is different from the piezoelectric device according to the above embodiment in that the ceramic substrate 10 is not flat and has a recessed portion 41 at the center of the upper surface, and an annular outer frame 42 surrounds the recessed portion 41. It is in the structure formed. The same members as those in the piezoelectric device of FIG.
The ceramic substrate 10 has a plurality of external mounting terminals 16 on the lower surface of the ceramic substrate 11, and the resonator element bonding terminal 18 to which the piezoelectric resonator element 20 is bonded to the inner bottom surface of the recessed portion 41 provided on the other main surface. Have. The resonator element joining terminals 18 and other terminals (not shown) are connected to corresponding external mounting terminals 16 by intra-layer wirings (vias) 17.
The piezoelectric vibrating piece 20 is bonded while being electrically connected by a bonding member 30 such as a silver paste in a state where the external connection electrode provided on one end side thereof is aligned with the corresponding vibrating piece bonding terminal 18. The other end side is cantilevered as a free end.

The flat metal lid 19 is made of a metal such as Kovar, 42 alloy, or phosphor bronze.
The metal lid 19 includes a base material 19A made of Kovar (linear expansion coefficient: 5.5 ppm / ° C.), which is a metal material having a linear expansion coefficient close to that of the ceramic substrate (7 ppm / ° C.), and a base material A silver solder 19B as a brazing material laminated on the lower surface of the substrate by a clad method, and a nickel film 19C as an antioxidant film laminated on the upper surface of the base material 19A by a clad method. As the material of the base material 19A, 42 nickel and SUS can be used except for Kovar.
On the upper surface of the annular outer frame 42 of the ceramic substrate, the metallized layer 13 made of the electroless nickel film 15 formed by electroless plating is formed.

In the present invention, the electroless nickel film 15 functioning as a brazing material is interposed between the ceramic substrate 11 and the metal lid, so that the thickness of the silver braze 19B on the lower surface of the metal lid is not increased. Bonding strength and airtightness between the material 11 and the metal lid 19 can be enhanced. For this reason, it is possible to reduce the cost by reducing the thickness of the silver solder on the lower surface of the metal lid.
The metal lid 19 is irradiated with a laser beam or an electron beam as shown in FIG. 4B in a state where the outer peripheral lower surface is in contact with the electroless nickel film 15, and the silver solder 19B and the electroless nickel. By melting and solidifying the film 15, it is joined and integrated with the upper surface of the annular outer frame 42.
At this time, the lower surface of the outer periphery of the metal lid 19 is in contact with the electroless nickel film 15. However, when the laser beam 1 is irradiated on the upper surface of the metal lid as shown in FIG. 4A, the electroless nickel film is melted. The area 15a to be expanded extends beyond the direct joining region 35 that is in direct contact with the metal lid.
Since the inner end portion (inner melting portion) 15c in the melting range 15a is exposed inside the cavity T, it becomes a gas generation source composed of a phosphorus component, and the gas generated in the cavity T is an electronic component. It becomes a cause of deteriorating characteristics.

In the present invention, in order to cope with such a problem, as shown in FIG. 4C, it is laminated on the back surface of the base material 19A closer to the inner side than the silver brazing film 19B ′ laminated on the lower surface of the outer periphery of the metal lid. A part of the silver brazing film 19B ″ is melted, and the inner end portion 15c is formed by the covering brazing material region 36 formed by flowing the molten brazing material having increased fluidity upon flowing onto the exposed inner end portion 15c. It was made to completely coat.
In order to melt the silver brazing film 19B ″ in this way, for example, after the laser beam 1 is irradiated as shown in (b), the laser beam 2 is irradiated with the laser beam 1 as shown in (c). An amount of brazing material sufficient to cover the inner end portion 15c is melted by irradiating the outer surface of the metal lid body inside the range to form the coated brazing material region 36.

Alternatively, the surface diameter of the silver brazing films 19B ′ and 19B ″ may be simultaneously heated by increasing the spot diameter of the laser beam and melting each brazing material.
Thus, when the outer peripheral lower surface of the metal lid is joined to the electroless ceramic film 15 by irradiating the laser beam, the melting range of the electroless nickel film is expanded inside the cavity T and exposed in the cavity. The inner end portion 15c is formed, and the inner end portion 15c is covered by partially melting and flowing down the silver brazing film 19B "formed on the inner side of the metal lid at a position corresponding to the inner end portion 15c. Since the brazing material region 36 is completely covered, generation of gas from the inner end can be prevented.

Next, FIG. 5 is a flowchart showing an example of a method for manufacturing a piezoelectric device according to the present invention. FIG. 6 is a plan view showing a process of manufacturing a ceramic substrate using a green sheet.
In this example, the manufacturing method of the electronic device shown in FIGS. 1 and 2 will be described. However, the electronic device according to FIG. 4 can be manufactured by the same procedure.
The manufacturing process of the piezoelectric device 1 includes a pre-process for preparing the piezoelectric vibrating piece 20, the ceramic substrate 10, and the metal lid 19, and joining the piezoelectric vibrating piece 20 on the ceramic substrate 10 and then joining the metal lid 19. Thus, it can be roughly divided into a post-process (assembly process) for hermetically sealing the piezoelectric vibrating piece 20. First, an outline of the preparation of the piezoelectric vibrating piece 20 and the metal lid 19 in the previous process will be described.

In the preparation of the piezoelectric vibrating piece 20 shown in step S1-1, the piezoelectric vibrating piece 20 is manufactured so that the piezoelectric device 1 can be assembled. A plurality of piezoelectric vibrating reeds 20 can be collectively formed by arranging a plurality of large-size wafers obtained by cutting and polishing a piezoelectric material such as quartz into a predetermined size. The outline will be described. First, a large crystal substrate (crystal wafer) that is cut out at a predetermined cut angle with respect to the crystal axis and then polished to have a desired thickness and surface state is prepared. Then, the outer shape of the plurality of piezoelectric vibrating pieces 20 is formed on the quartz substrate by wet etching using photolithography. In addition, the outer shape of the piezoelectric vibrating piece 20 is efficiently connected to the crystal wafer (wafer) while being connected to the crystal wafer by a perforated break-off portion or the like so as not to be completely separated from the crystal substrate. It is preferable to flow. Then, by forming electrodes such as the excitation electrode 25 and the external connection electrode 26 by sputtering or vapor deposition, a plurality of piezoelectric vibrating reeds 20 are formed in a matrix on the quartz wafer.
In the preparation of the metal lid 19 shown in step S1-3, the metal lid 19 is manufactured so that the piezoelectric device 1 can be assembled. The metal lid 19 has a structure in which, for example, a nickel film 19C is laminated on the surface of a plate-like base material 19A made of a metal such as 42 alloy, Kovar, or phosphor bronze, and a silver solder 19B is laminated and integrated on the back surface by a cladding method. And forming a metal lid body 19 having a concave portion formed in the central portion and a contact leg portion 19c provided in an annular shape on the outer peripheral portion.

Next, the manufacturing process from manufacturing the ceramic substrate 10 to assembling the piezoelectric device 1 will be described.
In the present embodiment, a ceramic green sheet 51 is used as a base material of the ceramic substrate 10, and in manufacturing the ceramic substrate 10, the green sheet prepared in step S1-2 is fired in step S2. Next, in step S3, the wiring material 14, the resonator element joining terminal 18, and the external mounting terminal 19 are respectively formed on the fired green sheet by using a semi-additive method using copper. An electroless nickel film 15 is laminated on the surface of the wiring material 14 made of copper by electroless plating.
As described above, a green sheet in which a plurality of ceramic substrates 10 are formed in a matrix is completed by the steps from preparation of the green sheet 51 in step S1-2 to steps S2 and S3 (see FIG. 6).
At this stage, the green sheet 51 can be divided into individual ceramic substrates 10. For example, the green sheet 51 in which the plurality of piezoelectric device forming regions 1A are formed in a matrix is diced along vertical and horizontal dicing lines formed between the piezoelectric device forming regions 1A, and the like, for example. Can be obtained.

In the present embodiment, a method for efficiently assembling the piezoelectric device 1 in the state of the green sheet 51 on which the plurality of ceramic substrates 10 are formed will be described below.
In the piezoelectric device assembly process, first, as shown in step S4, the piezoelectric vibrating reed 20 prepared in step S1-1 is joined to each piezoelectric device forming region 1A of the green sheet 51. Specifically, first, a bonding member 39 such as a silver paste is applied to the vibrating piece bonding terminal 18 in each piezoelectric device forming region 1A by a dispenser or screen printing, and then provided on one end side of the piezoelectric vibrating piece 20. The formed external connection electrode 26 is positioned and temporarily fixed to the corresponding resonator element joining terminal 18. Then, a process according to the curing method of the joining member 39, for example, if the thermosetting joining member 39 is heated at a predetermined temperature, and if it is an ultraviolet curable joining member, the joining is performed by irradiating with ultraviolet rays. The member 39 is solidified, and the piezoelectric vibrating piece 20 is joined in a cantilevered manner.

Next, in step S5, the metal lid 19 is disposed in each piezoelectric device forming region 1A of the green sheet 51 to which the piezoelectric vibrating piece 20 is bonded. The silver brazing 19B on the lower surface of the contact leg 19c of the metal lid 19 is positioned in a positional relationship that is aligned with the metallized layer 13 (wiring material 14, electroless nickel film 15) on the ceramic substrate.
Next, in the metal lid joining process of step S6, as shown in FIG. 3A, the laser beam 1 having a required spot diameter is irradiated toward the upper surface of the contact leg 19c to silver brazing 19B. Is heated and melted to hermetically bond the contact leg and the metallized layer. At this time, since the electroless nickel film 15 constituting the surface layer of the metallized layer is melted together with the silver wax and then solidified, the airtightness can be further improved.
Furthermore, in this embodiment, after irradiating the laser beam 1, as shown in FIG. 3B, the laser beam 2 is irradiated on the outer surface of the metal lid inside the irradiation range by the laser beam 1, and the inner side A sufficient amount of brazing material for covering the end portion 15c is melted to form the covering brazing material region.
Alternatively, the surface diameter of the silver brazing films 19B ′ and 19B ″ may be simultaneously heated by increasing the spot diameter of the laser beam and melting each brazing material.

Thus, when the outer peripheral lower surface of the metal lid is joined to the electroless ceramic film 15 by irradiating the laser beam, the melting range of the electroless nickel film is expanded inside the cavity T and exposed in the cavity. The inner end portion 15c is formed, and a part of the silver brazing film 19B "formed on the inner side of the metal lid at a position corresponding to the inner end portion 15c is partially melted and allowed to flow down to thereby form the covering brazing material region 36. Since the inner end 15c is formed so as to be completely covered, generation of gas from the inner end can be prevented.
In addition, the above-described series of metal lid joining steps to the ceramic substrate 10 (metal lid arrangement in step S5 and metal lid joining in step S6) include, for example, an inert gas atmosphere such as nitrogen gas or argon gas. Alternatively, it is preferable to carry out in a reduced pressure space. As a result, the inside of the cavity T formed by the ceramic substrate 10 in which the piezoelectric vibrating piece 20 is accommodated and the metal lid 19 is filled with an inert gas, or is sealed and sealed in a decompression space. It is possible to effectively prevent the resonator element 20 from being corroded or deteriorated by oxygen or moisture in the atmosphere.
As described above, the plurality of piezoelectric devices 1 are formed in a matrix on the green sheet 51 through the series of steps described above.

Next, in the dividing step of step S7, the green sheet 51 that has undergone the steps up to step S6 described above is divided to obtain a plurality of pieces of piezoelectric devices 1 simultaneously.
The piezoelectric device 1 obtained by the dividing step is completed by inspecting electrical characteristics and appearance quality in step S8, and a series of manufacturing processes of the piezoelectric device 1 is completed.
The specific form described in the above embodiment and the modification, for example, the shape of the ceramic substrate 10 or the piezoelectric vibrating piece 20 as an electronic component is not limited.
Similarly, the position and shape of each electrode, wiring, terminal, etc. are not limited to the above embodiment.

Moreover, in the said embodiment and modification, the piezoelectric devices 1 and 40 which mounted the piezoelectric vibrating piece 20 as an electronic component were demonstrated as an example of an electronic device. However, the configuration shown in the above embodiment and the modification is not limited to this, and various configurations of structures in which various electronic components such as a semiconductor circuit element are bonded to a substrate as an electronic component and the electronic component is hermetically sealed with a metal lid. It can be applied to a package structure of an electronic device.
Specifically, for example, as shown in FIG. 7, the package structure of a piezoelectric oscillator 60 in which a semiconductor circuit element 61 constituting an oscillation circuit is incorporated inside a cavity T of a package of a piezoelectric vibrator such as a crystal vibrator or outside the package. The present invention can also be applied to.
Also in this piezoelectric oscillator, the coated brazing material region 36 formed by partially melting and flowing down the silver brazing film 19B "formed inside the side wall 19b standing from the inner end of the contact leg 19c. Since the inner melting portion 15b is completely covered, generation of gas from the inner melting portion can be prevented.

  Next, FIG. 9 is a schematic configuration diagram showing the configuration of the electronic apparatus according to the present invention. The electronic apparatus 70 includes the piezoelectric devices 1 and 40 described above. Examples of the electronic device 70 using the piezoelectric devices 1 and 40 include a transmission device. In these electronic devices 70, the piezoelectric device is used as a reference signal source, a voltage variable piezoelectric oscillator (VCXO), or the like, and can provide a small and favorable electronic device.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric device, 10 ... Ceramic substrate, 11 ... Ceramic base material, 12 ... Outer peripheral upper surface, 13 ... Metallized layer, 14 ... Wiring material, 15 ... Electroless nickel film, 15a ... Range where electroless nickel film melts, 15b , 15c ... inner melting part, 16 ... external mounting terminal, 18 ... vibrating piece joint terminal, 19 ... metal lid, 19A ... base material, 19B, 19B ', 19B "... brazing material (silver brazing), 19C ... nickel film , 19a ... horizontal part, 19b ... side wall part, 19c ... contact leg part, 20 ... piezoelectric vibrating piece, 25 ... excitation electrode, 26 ... external connection electrode, 30 ... joining member, 35 ... direct joining region, 36 ... covering brazing Material region, 40 ... electronic device, 41 ... concave portion, 42 ... annular outer frame, 51 ... green sheet, 60 ... piezoelectric oscillator, 61 ... oscillation circuit element, 70 ... electronic device

Claims (7)

An insulating substrate comprising a metallized layer comprising an electroless nickel film;
An electronic component bonded on one surface of the insulating substrate;
A metal lid that has a brazing material layer on one surface including a peripheral edge, and joins the peripheral edge to the metallized layer with the brazing material to form an internal space for accommodating the electronic component;
The electronic device, wherein the electroless nickel film in the internal space is covered with a brazing material. One surface where the electronic component is joined to the insulating base is a flat surface,
The electronic device according to claim 1, wherein the metal lid has a recess for forming the internal space.   The electronic device according to claim 1, wherein the metallized layer is composed of copper and the electroless nickel film covering an outer surface of the copper. A method for manufacturing an electronic device according to any one of claims 1 to 3,
Preparing the electronic component, the insulating substrate, and the metal lid, respectively;
Bonding the electronic component on the insulating substrate;
Disposing the metal lid on the insulating substrate;
Irradiating a heating light or an electron beam inside the peripheral edge to melt the brazing material in the internal space; and
The manufacturing method of the electronic device characterized by the above-mentioned.   The method of manufacturing an electronic device according to claim 4, wherein the step of melting the brazing material in the internal space and the step of joining the lid are performed simultaneously. The electronic device according to any one of claims 1 to 3 is a piezoelectric vibrator,
A piezoelectric oscillator comprising a semiconductor element.   The electronic device carrying the electronic device as described in any one of Claims 1 thru | or 3.

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