JP2002353358A - Crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome such a problem that when a lid is welded to a substrate, a crack is generated in the substrate, so it is impossible to accommodate hermeti cally a crystal resonator within a container comprising the substrate and lid. SOLUTION: In a crystal device 6 which comprises a substrate 1 having a mounting portion 1a on a top face thereof, and a wiring layer 2 derived from the mounting portion 1a to an external surface; a metal frame 8 which is mounted on the top face of the substrate 1 to surround the mounting portion 1a; a crystal resonator 5 which is firmly fixed to the mounting portion 1a of the substrate with electrodes thereof being electrically connected to the wiring layer 2; and a lid 3 which is welded on the metal frame 8 to hermetically accommodate internally the crystal resonator 5, a coefficient of linear thermal expansion of the substrate 1 is 14×10<-6> / deg.C to 20×10<-6> / deg.C (40 to 400 deg.C), a rigidity modulus of the lid 3 is 50 GPa or below, and at least an area of the metal frame 8 to which the lid 3 is welded is coated with a plated layer of nickel containing 9 to 10 weight percent of phosphorus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal device used as a time and frequency reference source in an information processing device such as a computer or an electronic device such as a mobile phone.

[0002]

2. Description of the Related Art In general, a crystal device used as a time and frequency reference source in an information processing apparatus such as a computer or an electronic apparatus such as a mobile phone is formed by forming electrodes for applying a voltage on a rectangular crystal substrate. The crystal oscillator
It is formed by being hermetically housed in a crystal oscillator housing package.

The package for accommodating the crystal unit is generally made of an electrically insulating material such as an aluminum oxide sintered body, and has a concave portion for forming a space for accommodating the crystal unit at the center of the upper surface, and a concave surface. A base having a wiring layer made of a metal material such as a refractory metal such as tungsten and molybdenum, which is led out to the outer surface, and a lid made of a metal material such as an iron-nickel-cobalt alloy and an iron-nickel alloy. Have been.

[0004] Then, the electrodes of the crystal unit are attached to the wiring layer exposed on the inner surface of the concave portion of the substrate and the peripheral surface of the substrate via a conductive adhesive, whereby the crystal unit is bonded and fixed in the concave portion. And then electrically connected to the wiring layer. Thereafter, a lid is attached to the upper surface of the base, and the crystal resonator is hermetically housed in a container formed of the base and the lid, thereby obtaining a crystal as a product. The device is completed.

In general, the lid is attached to the substrate by forming a metallizing layer for brazing so as to surround the concave portion on the upper surface of the substrate and forming an iron-nickel-cobalt alloy or the like on the metallizing layer for brazing. A metal frame made of an iron-nickel alloy or the like is attached via a brazing material such as silver brazing, and a lid made of a metal material is joined to the metal frame by a welding method such as seam welding or electron beam welding. It is done by means. In this case, on the surface of the metal frame, a nickel plating layer is usually formed in advance by electroplating using a conventionally well-known watt bath, sulfamic acid bath, or the like. Practically, the nickel plating layer is heated and melted by a welding device,
It is performed by joining a lid to a metal frame via nickel.

Further, mounting of the crystal device on an external electric circuit board is performed by connecting a wiring layer led to the outer surface of the base to a wiring conductor of the external electric circuit board via a conductive connecting material such as solder. The crystal oscillator is electrically connected to an external electric circuit via a wiring layer, and vibrates at a predetermined frequency according to a voltage applied from the external electric circuit.

[0007]

However, the conventional crystal device has a linear thermal expansion coefficient of about 18 ×
^10-6 / ° C (40-400 ° C), whereas the linear thermal expansion coefficient of the base made of an aluminum oxide sintered body on which the quartz oscillator is mounted and fixed is about 7 × ^10-6 / ° C (40-400 ° C). ~ 40
0 ° C.), and the conductive adhesive material for fixing the crystal unit to the base is made of a hard epoxy resin and conductive powder and is hardly deformed. When heat is repeatedly applied to both the crystal and the crystal unit, the thermal stress caused by the difference in linear thermal expansion coefficient between the base and the crystal unit repeatedly acts on the conductive adhesive, causing mechanical destruction of the conductive adhesive. As a result, the fixing of the crystal unit via the conductive adhesive is broken, and as a result, the function as a crystal device is lost.

In order to solve the above-mentioned drawbacks, the linear thermal expansion coefficient of the base is increased so as to approximate the linear thermal expansion coefficient of the quartz oscillator, and a large thermal stress is generated between the base and the quartz oscillator. Means for preventing such a situation can be considered.

However, when the coefficient of linear thermal expansion of the substrate is increased so as to approximate the crystal oscillator, iron-nickel
The cover made of a cobalt alloy, an iron-nickel alloy, or the like has a linear thermal expansion coefficient of about 4 × 10 ⁻⁶ / ° C. to 6 × 10 ⁻⁶ / ° C. (40 to
400 ° C.), and has a large difference (about 10 × 10 ⁻⁶ / ° C. or more) with respect to the coefficient of linear thermal expansion with respect to the base. The lid made of iron-nickel-cobalt alloy, iron-nickel alloy, etc. Since the rigidity is as high as about 80 to 100 GPa and it is difficult to deform, if the heat is repeatedly applied to the base and the lid with the change of the external environment, the difference in the linear thermal expansion coefficient between the base and the lid may be caused. As a result, a large thermal stress is generated, and the thermal stress causes cracks and cracks in the base, and the hermetic sealing of the container formed of the base and the lid is broken. As a result, the base is composed of the lid and the lid. The disadvantage is that the quartz oscillator housed inside the container cannot be operated accurately and stably for a long period of time.

Further, in the conventional crystal device, since the melting point of the nickel plating layer applied to the metal frame by the electrolytic plating method is as high as about 1000 ° C. or more, the nickel plating layer is melted to form the metal frame. When welding the lid,
A large thermal shock at a high temperature exceeding 1000 ° C. is transmitted to the base and causes cracks in the base. As a result, the hermetic seal of the container consisting of the base and the lid is broken, and the quartz oscillator can be accurately and reliably used for a long time. Further, it has a disadvantage that it cannot be operated stably.

The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a highly reliable crystal device capable of operating a crystal oscillator normally and stably for a long period of time. .

[0012]

According to the present invention, there is provided a quartz crystal device having a mounting portion on an upper surface, a base having a wiring layer extending from the mounting portion to an outer surface, and a base attached to the upper surface of the base. A metal frame surrounding the mounting portion, a crystal oscillator fixed to the mounting portion of the base, and having an electrode electrically connected to the wiring layer; and A lid that hermetically accommodates the element therein, wherein the base has a coefficient of linear thermal expansion of 14 ×
10 ⁻⁶ / ° C. to 20 × 10 ⁻⁶ / ° C. (40 to 400 ° C.), the rigidity of the lid is 50 GPa or less, and phosphorus is applied to at least a region of the metal frame to which the lid is welded. 9
A nickel plating layer containing about 12% by weight is applied.

According to the crystal device of the present invention, the coefficient of linear thermal expansion of the substrate is from 14 × 10 ⁻⁶ / ° C. to 20 × 10 ⁻⁶ / ° C.
(40-400 ° C.), and approximated to the linear thermal expansion coefficient of the crystal unit. After fixing the crystal unit to the base, heat was repeatedly applied to both the base and the crystal unit with changes in the external environment. Even if it acts, no large thermal stress is generated between the base and the quartz oscillator due to the difference in linear thermal expansion coefficient between them, and this allows the quartz oscillator to be securely and firmly fixed to the base. As a result, the crystal oscillator can be operated accurately.

At the same time, according to the quartz crystal device of the present invention, since the rigidity of the lid is set to 50 GPa or less, there is a difference in linear thermal expansion coefficient between the base and the lid, and heat acts on both. Even if a large thermal stress is generated between the two, the thermal stress is effectively absorbed by appropriately deforming the lid, and as a result, the lid is securely and firmly attached to the base, and the The hermetic sealing is completed, whereby the quartz oscillator accommodated in the container can be operated stably and accurately for a long period of time.

Further, according to the quartz crystal device of the present invention, phosphorus is applied to at least a region of the metal frame to which the lid is welded.
Since a nickel plating layer containing 12% by weight and having a melting point of as low as about 850 ° C. was applied, when this nickel plating layer was melted and the lid was welded to the metal frame, a large thermal shock was transmitted to the base and cracks were generated. Occurs little, and as a result, the hermetic sealing of the container consisting of the base and the lid is completed, and the quartz oscillator housed inside the container can be operated accurately and stably for a long period of time. .

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a crystal device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of the crystal device of the present invention. In FIG. 1, reference numeral 1 denotes a base, 2 denotes a wiring layer, and 3 denotes a lid. A quartz crystal device 6 is formed by hermetically housing a quartz oscillator 5 in a container 4 formed by the base 1 and the lid 3.

The substrate 1 has a linear thermal expansion coefficient of 14 × 10
^A concave portion 1a made of a glass-ceramic sintered body or crystalline glass of ^-6 / ° C. to 20 × 10 ^-6 / ° C. (40 to 400 ° C.), and serving as a cavity for accommodating the quartz oscillator 5 on its upper surface
Is provided, and the quartz oscillator 5 is accommodated in the concave portion 1a.

The substrate 1 has a coefficient of linear thermal expansion of 14 × 1.
0 ⁻⁶ / ° C. to 20 × 10 ⁻⁶ / ° C. (40 to 400 ° C.), and the coefficient of linear thermal expansion of the crystal unit 5 (about 18 × 10 ⁻⁶ /
(° C .: 40 to 400 ° C.), so that even after the quartz resonator 5 is mounted and accommodated in the concave portion 1a of the base 1, even if heat acts on both, no large thermal stress is generated between them. As a result, the quartz oscillator 5 can be securely and firmly fixed in the concave portion 1a of the base 1.

The coefficient of linear thermal expansion is 14 × 10 ⁻⁶ / ° C. to 2
The substrate 1 at 0 × 10 ⁻⁶ / ° C. (40 to 400 ° C.) is, specifically, a glass containing 5 to 60% by weight of barium oxide and a linear thermal expansion coefficient at 40 to 400 ° C. of 8 × 10 ^{− 6}
/ Filler containing metal oxide particles of at least / ° C,
0.1 to 25% by weight of a zirconium (Zr) compound in the glass and / or filler in terms of ZrO ₂
Is preferably used.

It is important for the glass ceramic sintered body to use glass containing 5 to 60% by weight of barium oxide as a glass component. Since the barium oxide-containing glass has a low softening point and a relatively high coefficient of linear thermal expansion, it is possible to reduce the amount of glass and to add a large amount of filler having a high thermal expansion, so that a high linear heat A sintered body having an expansion coefficient can be easily obtained. When the amount of barium oxide is in the range of 5 to 60% by weight, if the amount is less than 5% by weight, it becomes difficult to lower the softening point of the glass and the linear thermal expansion coefficient becomes low. If it is more than 60% by weight, vitrification is difficult, characteristics are likely to be unstable, and chemical resistance is significantly reduced. In particular, the amount of barium oxide is desirably 20 to 40% by weight.

It is desirable that lead (Pb) is not substantially contained in the glass. This is because lead has toxicity and requires special equipment and control for preventing poisoning during the manufacturing process, so that a sintered body cannot be manufactured at low cost. Considering the case where lead is inevitably mixed as an impurity, the content of lead is desirably 0.05% by weight or less.

Further, the linear thermal expansion coefficient of the glass at 40 to 400 ° C. is 7 × 10 ⁻⁶ / ° C. to 18 × 10 ⁻⁶ / ° C., particularly 8 × 10 ⁻⁶ / ° C. to 13 × 10 ⁻⁶ / ° C. Desirably. This is because if the coefficient of linear thermal expansion deviates from the above range, a difference in linear thermal expansion with the filler occurs, which causes a reduction in the strength of the glass ceramic sintered body.

Further, the barium oxide-containing glass preferably has a sag point of 400 to 800 ° C., particularly preferably 400 to 700 ° C. This is because when forming a mixture comprising barium oxide-containing glass and a filler, a molding binder such as an organic resin is added. It is necessary to match the firing conditions of the above. If the yield point is lower than 400 ° C., the sintering of the glass starts at a low temperature. For example, the sintering of silver (Ag), copper (Cu), or the like starts. Simultaneous firing with the wiring layer 2 at a temperature of 600 to 800 ° C. cannot be performed, and densification of the molded body starts at a low temperature, so that the binder cannot be decomposed and volatilized, resulting in a binder component remaining and affecting properties. That's why. If the yield point is higher than 800 ° C., sintering becomes difficult unless the amount of glass is increased, so that a large amount of expensive glass is required, which increases the cost of the sintered body.

As the glass satisfying the above-mentioned characteristics, at least silicon oxide (Si)
O ₂ ) in a proportion of 25 to 60% by weight, with the balance being boron oxide (B ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), calcium oxide (CaO), magnesium oxide (MgO),
It is composed of at least one selected from the group consisting of titanium oxide (TiO ₂ ) and zinc oxide (ZnO).

On the other hand, as a filler component to be combined with the glass, at least a metal oxide having a linear thermal expansion coefficient of at least 8 × 10 ⁻⁶ / ° C. at 40 to 400 ° C. is required to increase the thermal expansion of the sintered body. This is important for planning. If a metal oxide having a linear thermal expansion coefficient of not less than 8 × 10 ⁻⁶ / ° C. is contained, the linear thermal expansion coefficient of the glass ceramic sintered body is 14 ×
This is because the temperature cannot be increased to 10 ⁻⁶ / ° C. or more.

Such a linear thermal expansion coefficient is 8 × 10 ⁻⁶ / ° C.
The above metal oxides include cristobalite (SiO
₂ ), quartz (SiO ₂ ), tridymite (Si
O _2), forsterite (2MgO · SiO _2), wollastonite (CaO · SiO _2), Monty Sera Knight _{(CaO · MgO · SiO 2)} , nepheline (Na ₂ O
・ Al ₂ O ₃・ SiO ₂ ), melvinite (3CaO ・ M)
gO.2SiO ₂ ), Akermite (2CaO.MgO)
· 2SiO ₂₎ magnesia (MgO), Kanegiaito _{(Na 2 O · Al 2 O} 3 · 2SiO 2), enstatite (MgO · SiO _2), petalite (LiAlSi
₄ O _10), at least one or more can be mentioned from the group of jade _{(Na 2 O · Al 2 O} 3 · 4SiO 2). Among them, one selected from the group consisting of SiO ₂ -based materials such as cristobalite, quartz, and tridymite, and forsterite and enstatite is desirable for achieving high thermal expansion.

The glass and filler are mixed in an appropriate ratio according to the purpose such as the firing temperature and the thermal expansion characteristics of the finally obtained glass ceramic sintered body. The barium oxide-containing glass has a shrinkage initiation temperature of 700 ° C. or lower when no filler is added, and melts at 850 ° C. or higher, so that the wiring layer 2 and the like cannot be provided. However, by mixing the filler, precipitation of crystals occurs during the firing process, and a liquid phase for liquid phase sintering of the filler component can be formed at an appropriate temperature. In addition, since the shrinkage start temperature of the entire molded body can be increased, by adjusting the content of the filler, it is possible to match the simultaneous firing conditions with the wiring layer 2.

The ratio of the glass to the filler is 20 to 80% by volume of the glass powder and 80 to 20% by volume of the filler powder.
It is preferable to set the ratio to volume%. The reason that the amounts of the glass and the filler component are in the above range is that the amount of the glass component is less than 20% by volume, in other words, the amount of the filler is 80%
When the content is more than the volume percentage, it is difficult to perform liquid phase sintering, and the firing temperature becomes high, and the wiring layer 2 may be melted at the same time as the simultaneous firing with the wiring layer 2. If the content of the glass is more than 80% by volume, in other words, if the content of the filler is less than 20% by volume, the characteristics of the sintered body greatly depend on the characteristics of the glass, and it becomes difficult to control the material characteristics. This causes a problem that simultaneous firing with the wiring layer 2 becomes difficult due to the lowering. In addition, the cost of raw materials tends to increase due to the large amount of glass.

It is desirable that the amount of the filler component is appropriately adjusted according to the yield point of barium oxide.
That is, when the yield point of the glass is as low as 400 to 700 ° C., the sinterability at a low temperature is enhanced, so that the content of the filler is 4%.
A relatively large amount of 0 to 80% by volume can be blended. On the other hand, when the yield point of the glass is as high as 700 to 800 ° C., the sinterability is reduced. Therefore, the content of the filler is desirably relatively low, that is, 20 to 50% by volume.

The glass ceramic sintered body further comprises a zirconium compound (Zr compound) in the filler component and / or the glass component.
₂ ) It is important that the content is 0.1 to 25% by weight in conversion. The Zr compound melts into the barium oxide-containing glass and acts to increase the oxidation resistance of the glass, whereby the chemical resistance of the glass ceramic sintered body can be improved, and after the treatment with an acidic solution or an alkaline solution. It is possible to suppress a change in the appearance of the glass ceramic sintered body and a deterioration in the adhesion strength of the wiring layer 2.

As the Zr compound, for example, ZrO
_Two, ZrSiO_Four, CaO / ZrO_Two, ZrB_Two, ZrP_Two
O₇And at least one selected from the group of ZrB.
It is. This Zr compound is a filler component as a compound powder.
Mix as one of the ingredients. In this case, Zr conversion at the time of addition
Compound, especially ZrO_TwoDepending on the BET specific surface area of the glass
The chemical resistance of the ceramic sintered body tends to change.
ET specific surface area is 25m ^Two/ G or more
And BET specific surface area is 25m^TwoLess than / g
The effect of improving the quality tends to be small. Also other formulations
As a form, barium oxide (Ba) is used as glass powder.
O), silicon oxide (SiO_TwoGill oxide as an ingredient other than
Conium (ZrO_Two) May be used.
No.

When the Zr compound is in the above range, the effect of improving the chemical resistance is low when the amount is less than 0.1%, and the linear thermal expansion coefficient is 14 × 10 when the amount is more than 25% by weight.
^This is because it is lower than ^-6 / ° C. In particular, the Zr compound is Z
0.2 to 10% by weight in terms of rO ₂ is desirable.

In addition, chromium oxide,
At least one selected from the group consisting of cobalt oxide, manganese oxide, and nickel oxide may be blended. The glass ceramic sintered body is prepared by adding a suitable molding organic resin binder to a mixture of the glass powder and the filler powder prepared as described above, and then forming the mixture by a doctor blade method, a rolling method, a mold pressing method, or the like. It is manufactured by molding into an arbitrary shape, for example, a sheet by means, and then firing.

In the substrate 1, the wiring layer 2 is extended from the surface of the concave portion 1a to the outer surface, and the electrode of the crystal unit 5 is electrically connected to the conductive adhesive 7 at the portion of the wiring layer 2 exposed on the surface of the concave portion 1a. The portion led out to the outer surface is connected to the wiring conductor of the external electric circuit board via a brazing material such as solder.

The wiring layer 2 functions to electrically connect the crystal resonator 5 housed in the recess 1a to the wiring conductor of the external electric circuit board, and is made of copper, silver, nickel, palladium or gold. In the case of copper, a metal paste obtained by adding and mixing an appropriate organic solvent, an organic binder, and the like to copper powder is used to form a green sheet for the base 1. It is formed by printing and applying a predetermined pattern on the surface by a screen printing method or the like.

If the exposed surface of the wiring layer 2 is covered with a plating layer (not shown) made of a metal having good corrosion resistance such as nickel, copper, gold and the like and good wettability of the brazing material, the wiring Oxidation and corrosion of the layer 2 can be favorably prevented, and the wettability of a brazing material such as solder to the wiring layer 2 can be improved. It can be made easier and more reliable. Accordingly, the wiring layer 2 has a surface exposed to a plating layer of nickel, copper, gold, or the like, for example,
It is preferable to coat with a nickel or nickel alloy plating layer having a thickness of 1 μm to 10 μm and a gold plating layer having a thickness of 0.1 to 3 μm which are sequentially applied.

The surface of the wiring layer 2 is made of nickel, copper,
When coating with a plating layer such as gold, the arithmetic average roughness (Ra) of the outermost surface is 1.5 μm or less, and the root mean square roughness (R)
If ms) is set to 1.8 μm or less, the reflectance of light on the outermost surface becomes 40% or more, and when bonding the crystal unit 5 to the wiring layer 2 via the conductive adhesive 7, work such as positioning thereof is performed. Becomes easier. Therefore, when the surface of the wiring layer 2 is coated with a plating layer of nickel, copper, gold, or the like, the arithmetic mean roughness (Ra) of the outermost surface is 1.5 μm or less, and the root mean square roughness (Rms) is 1 μm. 0.8 μm or less.

Furthermore, the arithmetic average roughness (Ra) of the outermost surface of the plating layer made of nickel, copper, gold or the like which covers the surface of the wiring layer 2 is 1.5 μm or less, and the root mean square roughness (Rm)
In order to make s) 1.8 μm or less, for example, the wiring layer 2 is immersed in an electrolytic nickel plating solution in which a brightener such as a sulfur compound is added to a conventionally well-known watt bath, and a nickel plating layer is formed on the surface of the wiring layer 2. And then immersed in a cyan-based electrolytic gold plating solution to apply a gold plating layer on the nickel plating layer surface.

Further, a quartz oscillator 5 is adhered and fixed to the wiring layer 2 via a conductive adhesive 7, and at the same time, the quartz oscillator 5
Are electrically connected to the wiring layer 2.

The conductive adhesive 7 is generally formed by adding a conductive powder such as a silver powder to a thermosetting resin such as an epoxy resin. Positioning and setting is performed via an uncured adhesive made by adding a conductive powder to an uncured thermosetting resin, and the uncured thermosetting resin is heated and cured to place the crystal unit 5 in the concave portion 1a. And the electrodes of the crystal unit 5 are electrically connected to the wiring layer 2.

The base 1 on which the crystal unit 5 is adhered and fixed via a conductive adhesive 7 has a cover 3 attached to the upper surface thereof via a metal frame 8, whereby the base 1 and the cover A quartz oscillator 5 is hermetically accommodated inside a container 4 composed of the body 3 to form a quartz device 6.

The metal frame 8 acts as a base metal material when the lid 3 is joined to the base 1, and is first attached to the upper surface of the base 1 so as to surround the recess 1 a on the upper surface of the base 1. A frame-shaped metallizing layer 9 for brazing is applied,
This is performed by brazing the metal frame 8 to the brazing metallization layer 9 via a brazing material such as silver brazing.

The brazing metallization layer 9 is
For example, the base 1 is made of the same material and the same method as the wiring layer 2.
It is formed at a position surrounding the recess 1a on the upper surface.

The joining of the lid 3 to the metal frame 8 is as follows.
For example, this is performed by employing seam welding. Specifically, as shown in FIG. 2, a nickel plating layer 10 is previously applied to at least a region of the metal frame 8 where the lid 3 is joined. , Nickel plating layer 10 on metal frame 8
The lid 3 is placed and brought into contact with the
Rolling while contacting a roller electrode along the outer edge of the lid 3 and applying a large current through the roller electrode to melt the nickel plating layer 10 located between the metal frame 8 and the lid 3. Done by

When the lid 3 is joined to the metal frame 8 by seam welding, the corner between the upper surface and the side surface of the metal frame 8 is formed to have a radius of curvature of 5 to 30 μm. Burrs are not formed on the upper surface side of the metal frame 8, and the metal frame 8 and the lid 3 are securely and firmly joined to make the reliability of hermetic sealing of the container 4 extremely high. Can be. Therefore, it is preferable that the metal frame 8 be rounded at the corner between the upper surface and the side surface with a radius of curvature of 5 to 30 μm.

Further, the lid 3 joined to the metal frame 8
Is a material having a rigidity of 50 GPa or less, specifically, copper,
It is made of a metal composed of one or more of gold and silver, or an alloy obtained by adding a metal such as nickel, aluminum, tin, zinc, or the like, or phosphorus, silicon, or the like. It is formed by performing well-known metal working such as working.

Since the lid 3 has a rigidity of 50 GPa or less, the coefficient of linear thermal expansion of the base 1 and the coefficient of linear thermal expansion of the lid 3 are greatly different. Even if a large thermal stress is generated due to the coefficient difference, the thermal stress is effectively absorbed by appropriately deforming the lid 3, thereby preventing the substrate 1 from cracking or cracking. The lid 3 is firmly attached to the container 4 to completely seal the container tightly, and the quartz oscillator 5 housed inside the container 4 can be operated stably and accurately for a long period of time.

The cover 3 has a rigidity of 50 GP.
a, the cover 3 is hardly deformed, and the base 1 and the cover 3
And the lid 3 cannot sufficiently absorb the thermal stress generated between the substrate 1 and the base 1, causing cracks or cracks, or the hermetic sealing of the container 4 including the base 1 and the lid 3 is broken. Or Therefore, the lid 3 has a rigidity of 5
It is specified below 0 GPa. When the rigidity of the cover 3 is 15 GPa or less, the cover 3 is easily deformed, so that the cover 3 cannot be firmly joined to the base 1 by seam welding or the like. There is a risk that it may be difficult to normally operate the crystal oscillator 5 by contacting the crystal oscillator 5 or the like. Therefore, it is preferable that the rigidity of the cover 3 is set to 15 GPa to 50 GPa.

In the crystal device 6 of the present invention,
It is important that the nickel plating layer 10 attached to the metal frame 8 contains 9 to 12% by weight of phosphorus.

The nickel plating layer 10 containing 9 to 12% by weight of phosphorus has a melting point of about 850 due to the action of phosphorus.
It is as low as about ° C. For this reason, when the lid 3 is placed on the metal frame 8 and abutted and the roller electrode is rolled along the outer edge of the lid 3 to apply a large current to perform welding,
Cracks are hardly generated in the base 1 due to the transmission of a large thermal shock to the quartz resonator. As a result, the container 4 including the base 1 and the lid 3 is completely airtightly sealed, and 5 can be operated accurately and stably over a long period of time.

The nickel plating layer 10 containing 9 to 12% by weight of phosphorus contains, for example, nickel sulfate as a nickel supply source and sodium hypophosphite as a reducing agent as main components, and EDTA (ethylenediaminetetraacetic acid). ), An organic acid such as acetic acid and tartaric acid or a complexing agent such as a sodium salt thereof, and an electroless nickel plating solution obtained by adding a stabilizer such as a sulfur compound to a predetermined temperature and pH.
It is formed by immersing at least a region of the metal frame 8 to which the lid 3 is bonded in the plating solution for a predetermined time. In this case, the phosphorus content in the nickel plating layer 10 is set to a predetermined range by adjusting conditions such as the concentration of a reducing agent in the plating solution, the amount of a complexing agent, a stabilizer, or the like, or the pH and temperature. be able to.

When the content of phosphorus is less than 9% by weight, the melting point of the nickel plating layer 10 cannot be sufficiently lowered, and when the lid 3 is joined to the metal frame 8 by welding, cracks are formed on the base 1. If the content exceeds 12% by weight, it becomes hard and brittle, so that the reliability of joining the lid 3 to the metal frame 8 via the nickel plating layer 10 becomes low. Therefore, the content of phosphorus in the nickel plating layer 10 needs to be 9 to 12% by weight.
It is even more preferred that the content be 1% by weight.

When the lid 3 is welded to the metal frame 8, the nickel plating layer 10 has a thickness of 0.5 μm.
If it is less than 5 mm, the amount of nickel is small, so that it is difficult to firmly weld the lid 3 to the metal frame 8. If it exceeds 5 μm, the internal stress of the nickel plating layer 10 causes the metal frame 8 to be hardly welded.
There is a risk that the adhesion strength of the nickel plating layer 10 to the coating may decrease. Therefore, the nickel plating layer 10
Is preferably in the range of 0.5 μm to 5 μm.

Thus, according to the crystal device 6 described above,
When the wiring layer 2 is connected to an external electric circuit and a predetermined voltage is applied to the electrodes of the crystal oscillator 5, the crystal oscillator 5 vibrates at a predetermined frequency, and an information processing device such as a computer or an electronic device such as a mobile phone. Used as a time and frequency reference source in the device.

It should be noted that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention. For example, as shown in FIG.
If a projection 11 having a height of about 30 μm to 100 μm is formed on a part of the wiring layer 2, the projection 11 serves as a spacer to secure a certain space between the wiring layer 2 and the crystal unit 5. In this case, a sufficient amount of the conductive adhesive 7 enters the space, and the crystal unit 5 can be extremely firmly bonded and fixed to the wiring layer 2.

In the above-described quartz crystal device 6, the concave portion 1a is provided on the upper surface of the base 1, and the quartz resonator 5 is accommodated in the concave portion 1a. As shown in FIG. The present invention can also be applied to a crystal device 6 in which a quartz oscillator 5 is mounted and fixed thereon, and the fixed quartz oscillator 5 is hermetically sealed with a bowl-shaped lid 3.

In the above-described embodiment, the lid 3 is welded to the metal frame 8 by seam welding. However, this is irradiated with an electron beam along the outer edge of the lid 3, and the thermal energy May be performed by electron beam welding.

[0059]

According to the quartz crystal device of the present invention, the coefficient of linear thermal expansion of the substrate is 14 × 10 ⁻⁶ / ° C. to 20 × 10 ⁻⁶ / ° C.
(40-400 ° C.), and approximated to the linear thermal expansion coefficient of the crystal unit. After fixing the crystal unit to the base, heat was repeatedly applied to both the base and the crystal unit with changes in the external environment. Even if it acts, no large thermal stress is generated between the base and the quartz oscillator due to the difference in linear thermal expansion coefficient between them, and this allows the quartz oscillator to be securely and firmly fixed to the base. As a result, the crystal oscillator can be operated accurately.

At the same time, according to the quartz crystal device of the present invention, since the rigidity of the lid is set to 50 GPa or less, there is a difference in linear thermal expansion coefficient between the base and the lid, and heat acts on both. Even if a large thermal stress is generated between the two, the thermal stress is effectively absorbed by appropriately deforming the lid, and as a result, the lid is securely and firmly attached to the base, and the The hermetic sealing is completed, whereby the quartz oscillator accommodated in the container can be operated stably and accurately for a long period of time.

Further, according to the quartz crystal device of the present invention, phosphorus is applied to at least a region of the metal frame to which the lid is welded.
Since a nickel plating layer containing 12% by weight and having a melting point of as low as about 850 ° C. was applied, when this nickel plating layer was melted and the lid was welded to the metal frame, a large thermal shock was transmitted to the base and cracks were generated. Occurs little, and as a result, the hermetic sealing of the container consisting of the base and the lid is completed, and the quartz oscillator housed inside the container can be operated accurately and stably for a long period of time. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a crystal device of the present invention.

FIG. 2 is a sectional view of a main part of the crystal device of the present invention.

FIG. 3 is a sectional view of a main part showing another embodiment of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base 1a ... Depression 2 ... Wiring layer 3 ... Lid 4 ... Container 5 ... Crystal oscillator 6 ... · Quartz device 7 ····· Conductive adhesive 8 ···· Metal frame 9 ···· Metallizing layer for brazing 10 ··· Nickel plating layer 11 ···

Claims (1)

[Claims] A base having a mounting portion on an upper surface and a wiring layer extending from the mounting portion to an outer surface; a metal frame attached to the upper surface of the base and surrounding the mounting portion; A quartz oscillator fixed to the mounting portion of the base body and having an electrode electrically connected to the wiring layer, and a lid that is welded onto the metal frame and hermetically accommodates the quartz oscillator therein. A linear device having a coefficient of linear thermal expansion of 14 × 10 ⁻⁶ / ° C. to 20 ×
^10-6 / ° C. (40 to 400 ° C.), nickel having a rigidity of 50 GPa or less and containing 9 to 12% by weight of phosphorus in at least a region of the metal frame to which the lid is welded. A quartz device having a plating layer applied thereto.