JP3906047B2 - Crystal device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a crystal device used as a time and frequency reference source in an information processing apparatus such as a computer and an electronic apparatus such as a mobile phone.
[0002]
[Prior art]
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 generally a crystal resonator in which a voltage application electrode is formed on a rectangular plate-shaped crystal substrate. Is housed in a quartz crystal housing package in an airtight manner.
[0003]
The crystal resonator housing package 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 resonator at the center of the upper surface, and an outer surface from the concave surface. A substrate having a wiring layer made of a metal material such as tungsten or molybdenum derived from tungsten, molybdenum, and the like, and a metal material such as iron-nickel-cobalt alloy or iron-nickel alloy, or an aluminum oxide sintered body, etc. And a lid made of a ceramic material.
[0004]
Then, the quartz resonator is adhered and fixed in the recess and the wiring layer by attaching the electrode of the crystal resonator to the wiring layer exposed on the inner surface of the concave portion of the substrate and the surrounding substrate surface via a fixing material. After that, the lid is attached to the upper surface of the base by bonding means such as adhesive or seam welding, and the crystal unit is hermetically accommodated inside the container composed of the base and the lid. By doing so, a crystal device as a product is completed.
[0005]
In general, as a fixing material for attaching a crystal resonator, a conductive adhesive made by mixing an organic resin such as an epoxy resin and a conductive powder such as silver powder as a main material is used. Yes.
[0006]
Further, when the lid is attached to the base by seam welding, a frame-like brazing metallization layer is usually formed around the recess of the base in advance, and a metal frame is brazed to the metallization layer. A method of seam welding the lid to the frame is used.
[0007]
Further, the mounting of the crystal device on the external electric circuit board is performed by connecting the wiring layer led to the outer surface of the base to the wiring conductor of the external electric circuit board through a conductive connecting material such as solder, The crystal resonator is electrically connected to the external electric circuit via the wiring layer, and vibrates at a predetermined frequency according to a voltage applied from the external electric circuit, and supplies a reference signal to the external electric circuit.
[0008]
[Problems to be solved by the invention]
However, in the conventional quartz device, the wiring layer formed on the base is formed of a refractory metal material such as tungsten, molybdenum or manganese, and the tungsten or the like has a specific electric resistance of 5.4 μΩ · cm (20 ° C. ) When the reference signal is propagated to the wiring layer, the reference signal is greatly attenuated, and the reference signal cannot be propagated accurately and reliably to the external electric circuit.
[0009]
The present invention has been devised in view of the above drawbacks, and an object of the present invention is to provide a crystal device capable of supplying a reference signal of a crystal resonator to an external electric circuit at high speed, accurately and reliably.
[0010]
[Means for Solving the Problems]
The present invention has a mounting portion for the crystal oscillator is mounted, a substrate having a wiring layer is derived toward the outer surface from the mounting portion, the conductive fixing member to the wiring layer of the front Ki搭 mounting portion through is fixed to a quartz crystal device comprising a crystal oscillator electrodes are electrically connected to the wiring layer, 25 to 80 wt% said substrate Si component in terms of SiO _2, Ba component Is 15 to 70% by weight in terms of BaO, 1.5 to 5% by weight in terms of B component in terms of B ₂ O ₃ , 1 to 30% by weight in terms of Al component in terms of Al ₂ O ₃ , and Ca component Is a sintered body containing more than 0 wt% and not more than 30 wt% in terms of CaO, the wiring layer is formed of a metal material having a specific electric resistance of 2.5 μΩ · cm or less, and the fixing material consists added epoxy resin rubber particles and conductive powder, the elastic modulus It is characterized in that .8GPa or less.
[0012]
According to the quartz crystal device of the present invention, the substrate has a Si component converted to SiO ₂ of 25 to 80% by weight, a Ba component converted to BaO of 15 to 70% by weight, and a B component converted to B ₂ O ₃ . A sintered body containing 1.5 to 5% by weight, 1 to 30% by weight of Al component converted to Al ₂ O ₃ , and more than 0% by weight and 30% by weight or less of Ca component converted to CaO. Since the sintering temperature of such a sintered body is as low as 800 to 1000 ° C., the wiring layer formed by simultaneous firing with the base body has a low specific electrical resistance of 2.5 μΩ · cm (20 ° C.) or less, such as copper or silver As a result, when the reference signal of the crystal resonator is propagated to the wiring layer, the reference signal is not greatly attenuated, and the reference signal is accurately and reliably supplied to the external electric circuit. Propagation is possible.
[0013]
Further, according to the quartz crystal device of the present invention, as the fixing material for fixing the quartz crystal resonator to the substrate, for example, an elastic material made of an epoxy resin or the like to which rubber particles are added has an elastic modulus of 2.8 GPa or less. Even if heat is repeatedly applied to the base and the crystal unit as a result of the change in temperature, and thermal stress due to the difference in the thermal expansion coefficient between the base and the crystal unit is repeatedly generated, It is absorbed by being deformed appropriately, and mechanical damage is not caused to the fixing material. As a result, it is possible to securely and firmly fix the crystal unit to the base for a long period of time. High reliability can be achieved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, the crystal device of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a sectional view showing an embodiment of a quartz crystal device according to the present invention. In FIG. 1, 1 is a substrate, 2 is a wiring layer, and 3 is a lid. The quartz crystal device 6 is formed by airtightly accommodating the quartz crystal resonator 5 in the container 4 formed by the base 1 and the lid 3.
[0015]
The substrate 1 is 25 to 80 wt% Si component in terms of SiO _2, 15 to 70 wt% Ba component in terms of BaO, B component in terms of B ₂ O ₃ 1.5 to 5 It is formed of a sintered body containing 1% by weight to 30% by weight, Al component converted to Al ₂ O ₃ and 1 to 30% by weight, and Ca component converted to CaO and exceeding 0% by weight and 30% by weight or less. A recess 1a serving as a space for accommodating the crystal resonator 5 is provided in the recess 1a, and the crystal resonator 5 is accommodated in the recess 1a.
[0016]
In the base 1, a wiring layer 2 is led out from the surface of the recess 1a to the outer surface, and the electrode of the crystal unit 5 is fixed to a portion exposed on the surface of the recess 1a of the wiring layer 2 such as a conductive adhesive. The portion that is bonded and fixed via 7 and led to the outer surface is connected to the wiring conductor of the external electric circuit board via a brazing material such as solder.
[0017]
The substrate 1 made of the sintered body includes, for example, a binder and a dispersant, a plasticizer, and an organic solvent mainly composed of an acrylic resin in a raw material powder such as SiO ₂ , BaO, B ₂ O ₃ , Al ₂ O ₃ , and CaO. The slurry is made into a green sheet (raw sheet) by adopting a doctor blade method or a calender roll method, and then the green sheet is subjected to appropriate punching processing and a plurality of these are formed. It is manufactured by laminating and baking at a temperature of about 800 ° C. to 1000 ° C.
[0018]
Since the firing temperature of the substrate 1 is as low as about 800 ° C. to 1000 ° C., the wiring layer 2 formed by simultaneous firing with the substrate 1 has a low specific electrical resistance of 2.5 μΩ · cm (20 ° C.) or less. As a result, when the reference signal of the crystal unit 5 is propagated to the wiring layer 2, the reference signal is not greatly attenuated, and the reference signal is accurately transmitted to the external electric circuit. And it becomes possible to propagate reliably.
[0019]
If the sintered body constituting the substrate 1 is less than 25% by weight of SiO ₂ , the dielectric loss becomes large, causing attenuation or delay in the reference signal of the crystal resonator propagating through the wiring layer 2. On the other hand, if it exceeds 80% by weight, the mechanical strength of the substrate 1 is greatly reduced, and at the same time, the firing temperature becomes high, making it difficult to fire simultaneously with the wiring layer 2 made of a metal material such as copper. Therefore, the amount of SiO ₂ is specified in the range of 25 to 80% by weight.
[0020]
Further, if the sintered body constituting the substrate 1 has a BaO content of less than 15% by weight, the firing temperature becomes high and it becomes difficult to fire simultaneously with the wiring layer 2 made of a metal material such as copper. When the weight percentage is exceeded, the dielectric loss increases and attenuation or delay is caused in the reference signal of the crystal resonator that propagates through the wiring layer 2. Therefore, the amount of BaO is specified in the range of 15 to 70% by weight.
[0021]
Further, the sintered body constituting the substrate 1 has a high firing temperature when B ₂ O ₃ is less than 1.5% by weight, and is difficult to be fired simultaneously with the wiring layer 2 made of a metal material such as copper. Further, if it exceeds 5% by weight, the mechanical strength of the substrate 1 is greatly reduced. Therefore, the amount of B ₂ O ₃ is specified in the range of 1.5 to 5% by weight.
[0022]
Furthermore, when the Al ₂ O ₃ content is less than 1% by weight, the sintered body constituting the substrate 1 has a high firing temperature and is difficult to be fired simultaneously with the wiring layer 2 made of a metal material such as copper. Further, if it exceeds 30% by weight, the dielectric loss increases and the reference signal of the crystal resonator that propagates through the wiring layer 2 is attenuated or delayed. Therefore, the amount of Al ₂ O ₃ is specified in the range of 1 to 30% by weight.
[0023]
Furthermore, the sintered body constituting the substrate 1 has a low sinterability and a low mechanical strength when CaO is not contained, and when it exceeds 30% by weight, the firing temperature becomes high. It becomes difficult to fire simultaneously with the wiring layer 2 made of a metal material such as. Therefore, the amount of CaO is specified in the range of more than 0% by weight and not more than 30% by weight.
[0024]
Further, the wiring layer 2 formed on the base body 1 has an action of electrically connecting the crystal resonator 5 accommodated in the recess 1a and the wiring conductor of the external electric circuit board, for example, gold, silver, If it is made of a metal material having a specific electric resistance of 2.5 μΩ · cm (20 ° C.) or less, such as copper, and if it is made of copper, add an appropriate organic solvent, organic binder, etc. to the copper powder. The obtained metal paste is formed by printing and applying a predetermined pattern on the surface of the green sheet to be the base 1 by a screen printing method or the like.
[0025]
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 and gold and good wettability with the brazing material, the wiring layer 2 is subject to oxidative corrosion. In addition to being able to prevent it well, it is possible to improve the wettability of the brazing material such as solder to the wiring layer 2, and the connection of the wiring layer 2 to the wiring conductor of the external electric circuit board is made easier and more reliable. Can be. Therefore, the wiring layer 2 has an exposed surface plated with nickel, gold or the like, for example, a nickel or nickel alloy plating layer with a thickness of 1 μm to 10 μm, and a gold plating layer with a thickness of 0.1 to 3 μm. It is preferable to coat with.
[0026]
When the surface of the wiring layer 2 is covered with a plating layer such as nickel or gold, the arithmetic average roughness (Ra) of the outermost surface is 1.5 μm or less and the root mean square roughness (Rms) is 1.8 μm or less. As a result, the reflectance of light on the outermost surface is 40% or more, and when the crystal unit 5 is fixed to the wiring layer 2 via the fixing member 7, the work such as positioning is facilitated. Therefore, when the surface of the wiring layer 2 is covered with a plating layer such as nickel or gold, the arithmetic average roughness (Ra) of the outermost surface is 1.5 μm or less and the root mean square roughness (Rms) is 1.8 μm. The following is preferable.
[0027]
Further, the arithmetic average roughness (Ra) of the outermost surface of the plating layer made of nickel, gold, or the like covering the surface of the wiring layer 2 is 1.5 μm or less, and the root mean square roughness (Rms) is 1.8 μm or less. In this case, the wiring layer 2 is immersed in an electrolytic nickel plating solution in which a brightening agent such as a sulfur compound is added to a well-known Watt bath so that the nickel plating layer is deposited on the surface of the wiring layer 2, and then the cyan electrolysis is performed. It is carried out by dipping in a gold plating solution and depositing a gold plating layer on the surface of the nickel plating layer.
[0028]
The wiring layer 2 is also the crystal oscillator 5 that a part (region exposed to the inner surface of the recess 1a) are fixed through the fixing member 7, the fixing member 7, rubber particles and conductive An epoxy resin added with a conductive powder and having an elastic modulus of 2.8 GPa or less.
[0029]
Since the elastic modulus of the fixing material 7 is 2.8 GPa or less and is easily deformed, heat repeatedly acts on the base 1 and the crystal resonator 5 in accordance with a change in the external environment. Even if thermal stress due to the difference in thermal expansion coefficient between the two is repeatedly generated during this period, the thermal stress is absorbed by appropriately deforming the fixing material 7, and mechanical damage is caused to the fixing material 7. As a result, the crystal resonator 5 can be securely and firmly fixed to the substrate 1 for a long period of time, and the long-term reliability of the crystal device 6 can be improved.
[0030]
When the elastic modulus of the fixing material 7 exceeds 2.8 GPa, thermal expansion of both the base 1 and the crystal unit 5 occurs when heat is repeatedly applied to both the base 1 and the crystal unit 5 in accordance with a change in the external environment. The thermal stress caused by the coefficient difference repeatedly acts on the fixing material 7, causing mechanical damage to the fixing material 7, and the fixing of the crystal unit 5 via the fixing material 7 is broken. Will drop significantly. Therefore, the fixing material 7 is specified to have an elastic modulus of 2.8 GPa or less, and more preferably 2 GPa or less.
[0031]
The fixing material 7 having an elastic modulus of 2.8 GPa or less is, for example, a ratio of 15 to 60% by weight of conductive powder such as silver powder with respect to an epoxy resin to which rubber particles such as acrylic rubber and isoprene rubber are added. Those added are preferably used.
[0032]
As the epoxy resin, epoxy resins such as bisphenol A type, bisphenol F type, rubber modified type, urethane modified type, etc., particularly those that are viscous (room temperature) when uncured are preferably used.
[0033]
In this case, the elastic modulus of the fixing material 7 can be reduced by increasing the amount of rubber particles added to the epoxy resin, and the state of the epoxy resin (structure, degree of crosslinking, degree of polymerization, type of curing agent, etc.) can be reduced. Accordingly, the elastic modulus of the fixing material 7 can be reduced to 2.8 GPa or less by appropriately controlling the addition amount of the rubber particles. When the amount of the rubber particles added to the epoxy resin exceeds 50% by weight, the fluidity of the uncured resin composition is greatly reduced, and the fixing material 7 is interposed between the electrode of the crystal unit 5 and the wiring layer 2. Are difficult to interpose uniformly, and it tends to be difficult to firmly fix the crystal unit 5 to the base 1. Therefore, when rubber particles are added to the epoxy resin, the addition amount is preferably 50% by weight or less within a range where the elastic modulus of the fixing material 7 is 2.8 GPa or less.
[0034]
When the elastic modulus of the fixing member 7 is less than 0.1 GPa, the fixing member 7 is easily deformed, so that it is difficult to securely bond and fix the crystal unit 5 to a predetermined position in the recess 1a of the base 1. Tend. Therefore, the elastic modulus of the fixing material 7 is preferably set to 0.1 GPa or more in the range of 2.8 GPa or less.
[0035]
The fixing material 7 having an elastic modulus of 2.8 GPa or less is not limited to the above-mentioned epoxy resin composition, but a low elastic modulus thermosetting resin such as a silicone resin, or a filler component such as silica in a silicone resin or the like. You may form by adding electroconductive powder to the added resin composition.
[0036]
The base body 1 to which the crystal resonator 5 is bonded and fixed via a fixing material 7 has a lid 3 attached to the upper surface thereof, so that the crystal vibration is placed inside the container 4 composed of the base body 1 and the lid body 3. The child 5 is housed in an airtight manner to form the crystal device 6.
[0037]
The lid 3 is formed of a metal material such as an iron-nickel-cobalt alloy or an iron-nickel alloy, or a ceramic material such as an aluminum oxide sintered body. For example, an iron-nickel-cobalt alloy ingot Is formed by performing known metal processing such as rolling and punching.
[0038]
Further, the lid 3 can be attached to the base body 1 by a method using a bonding material such as a brazing material, glass, or an organic resin adhesive, or by a welding method such as seam welding. When attaching 3 by seam welding, a frame-like brazing metallization layer 8 is usually applied around the recess 1a of the substrate 1 in the same manner as the wiring layer 2, and the brazing metallization is applied. A metal frame 9 is brazed to the layer 8 via a brazing material such as silver brazing, and then the metal lid 3 is placed on the metal frame 9 and the outer edge of the lid 3 is seam welded. Is done by doing. In this case, if the metal frame 9 is rounded with a radius of curvature of 5 to 30 μm at the corner between the upper surface and the side surface, no burr is formed on the upper surface side of the metal frame 9. When the lid 3 is seam-welded to the upper surface of the metal frame 9, both can be reliably and airtightly bonded. Therefore, it is preferable that the metal frame body 9 has a corner between the upper surface and the side surface thereof to have a roundness with a radius of curvature of 5 to 30 μm.
[0039]
Furthermore, when the metal frame 9 is rounded with a radius of curvature of 40 to 80 μm at the corner between its lower surface and side surface, the metal frame 9 is brazed to the brazing metallization layer 8. When joining via the material, a space is formed between the brazing metallized layer 8 and the lower surface side corner of the metal frame 9, and a large pool of brazing material is formed in the space, so that the metal frame 9 The bonding to the brazing metallization layer 8 becomes strong. Therefore, in order to firmly bond the metal frame 9 to the brazing metallization layer 8 via the brazing material, the corner between the lower surface and the side surface of the metal frame 9 is rounded with a curvature radius of 40 to 80 μm. It is preferable to form it.
[0040]
Thus, according to the crystal device 6 described above, by connecting the wiring layer 2 to an external electric circuit and applying a predetermined voltage to the electrodes of the crystal resonator 5, the crystal resonator 5 vibrates at a predetermined frequency, and the computer It is used as a reference source for time and frequency in information processing apparatuses such as mobile phones and electronic devices such as mobile phones.
[0041]
Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, as shown in FIG. If the protrusion 10 is formed in the portion, the protrusion 10 serves as a spacer to secure a certain space between the wiring layer 2 and the crystal resonator 5, and a sufficient fixing material 7 enters the space so that the crystal The vibrator 5 can be bonded and fixed to the wiring layer 2 very firmly.
[0042]
In the crystal device 6 described above, the substrate 1 is provided with the recess 1a and the crystal resonator 5 is accommodated in the recess 1a. As shown in FIG. 5 is also applicable to the crystal device 6 in which the fixed crystal unit 5 is hermetically sealed by the bowl-shaped lid 3.
[0043]
【The invention's effect】
According to the quartz crystal device of the present invention, the substrate has a Si component converted to SiO ₂ of 25 to 80% by weight, a Ba component converted to BaO of 15 to 70% by weight, and a B component converted to B ₂ O ₃ . A sintered body containing 1.5 to 5% by weight, 1 to 30% by weight of Al component converted to Al ₂ O ₃ , and more than 0% by weight and 30% by weight or less of Ca component converted to CaO. Since the sintering temperature of the sintered body is as low as 800 to 1000 ° C., the wiring layer formed by co-firing with the substrate has a low specific electrical resistance of 2.5 μΩ · cm (20 ° C.) or less, such as copper or silver. As a result, when the reference signal of the crystal resonator is propagated to the wiring layer, the reference signal is not greatly attenuated, and the reference signal is accurately and reliably supplied to the external electric circuit. Propagation is possible.
[0044]
Further, according to the quartz crystal device of the present invention, as the fixing material for fixing the quartz crystal resonator to the substrate, for example, an elastic material made of an epoxy resin or the like to which rubber particles are added has an elastic modulus of 2.8 GPa or less. Even if heat is repeatedly applied to the base and the crystal unit as a result of the change in temperature, and thermal stress due to the difference in the thermal expansion coefficient between the base and the crystal unit is repeatedly generated, It is absorbed by being deformed appropriately, and mechanical damage is not caused to the fixing material. As a result, it is possible to securely and firmly fix the crystal unit to the base for a long period of time. High reliability can be achieved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a quartz crystal device of the present invention.
FIG. 2 is a cross-sectional view of an essential part showing another embodiment of the quartz crystal device of the present invention.
FIG. 3 is a cross-sectional view showing another embodiment of the quartz crystal device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Base | substrate 1a ... Recessed part 2 ... Wiring layer 3 ... Cover body 4 ... Container 5 ... Crystal oscillator 6 ...・ Crystal device 7... Fixing material 8... Brazing metallized layer 9... Metal frame 10.

Claims (1)

Having a mounting portion for the crystal oscillator is mounted, it is fixed through a substrate having a wiring layer that is derived toward the outer surface, a conductive fixing material to the wiring layer of the front Ki搭 mounting portion from the mounting portion , a quartz crystal device comprising a crystal oscillator electrodes are electrically connected to the wiring layer, wherein the substrate is 25 to 80 wt% Si component in terms of SiO _2, in terms of Ba component in BaO to 15 to 70 wt%, 1.5-5 wt% B component in terms of _B 2 _{O 3,} 1 to 30 wt% Al component in terms of _Al 2 _{O 3,} Ca component terms of CaO a sintered body that contains less than 30 wt% more than 0% by weight, the wiring layer is formed of a metal material having a specific electric resistance of less 2.5μΩ · cm, and the fixing material, rubber particles and made of a conductive powder added with epoxy resin, the elastic modulus 2.8GP Crystal devices, wherein the or less.

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