JP2017188552A - Cap for electronic component and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cap for an electronic component having a surface with a brazing material with good durability and a method for manufacturing the same.SOLUTION: In a cap, a brazing material 2 is formed on a surface of a core material 1' having a dome shape. The brazing material 2 is formed by laminating a tin layer 3, an indium layer 4, and a gold layer 5 in this order from the side of the core material 1'. That is, the brazing material 2 has a metal layer of indium between the respective metal layers of gold and tin.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cap for an electronic component and a method for manufacturing the same.

  In order to suppress the deterioration of the vibration characteristics of the crystal unit, the crystal unit is arranged on the substrate, and a dome-shaped cap is joined to the substrate so as to cover the crystal unit, and the cap is sealed together with the substrate. The crystal vibrating device (electronic component) employs a configuration that forms

  Here, a brazing material is generally used for joining the cap and the substrate. Many of the brazing materials are made of gold and tin alloys having good durability. Therefore, a technique has been proposed in which a gold and tin plating layer or a gold and tin alloy plating layer is formed on the surface of the cap (see Patent Documents 1, 2, and 3).

JP2003-163298A JP-A-2002-009186 International Publication WO2008 / 105258 Pamphlet

  It is difficult to arrange the gold and tin plating layers in contact with each other using a plating technique. Further, there is a technique for plating an alloy of gold and tin, but this is an extremely expensive technique and is difficult to use industrially.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cap for an electronic component having a brazing material having a good durability on its surface and a method for manufacturing the same.

  In order to achieve the above object, a cap for an electronic component according to the present invention has a brazing material formed on the surface of a core material of the cap, and the brazing material is composed of indium, bismuth, It has one or more metal layers selected from lead, zinc, and silver.

  Here, one or more metal layers selected from indium, bismuth, lead, zinc, and silver may have a thickness of 0.1 μm or more.

  In order to achieve the above object, a cap for an electronic component according to the present invention has a brazing material formed on the surface of a core material of the cap, and the brazing material is an alloy of gold and tin with indium, bismuth, lead, zinc, silver. One or more metals selected from the group consisting of:

  In order to achieve the above object, a method for manufacturing a cap for electronic components according to the present invention includes at least one metal layer selected from indium, bismuth, lead, zinc, and silver between the metal layers of gold and tin. A low melting point metal layer having a low melting point metal layer is melted in contact with the core material of the cap, and then the melted low melting point metal layer is solidified, and the solidified low melting point metal layer and the core material are combined. It is made to adhere.

  In the present invention, it is possible to provide a cap for an electronic component having a brazing material having good durability on its surface and a method for manufacturing the same.

It is a top view of the cap concerning the 1st embodiment of the present invention. It is AA sectional drawing of FIG. FIG. 3 is an enlarged view of a region B in FIG. 2, illustrating a configuration of a surface layer portion of the cap according to the first embodiment of the present invention. It is sectional drawing which shows the state which comprised the crystal oscillation apparatus (electronic component) using the cap which concerns on the 1st Embodiment of this invention similarly to sectional drawing shown in FIG. It is sectional drawing which shows the cap which concerns on the 2nd Embodiment of this invention similarly to FIG. It is a manufacturing flowchart of the cap which concerns on the 2nd Embodiment of this invention. It is a figure which shows the manufacturing process of the cap which concerns on the 2nd Embodiment of this invention, and is an enlarged view of the part of the area | region C of FIG. 5 before passing through a 2nd heating process. It is a figure which shows the manufacturing process of the cap which concerns on the 2nd Embodiment of this invention, and is the enlarged view of the part of the area | region C of FIG. 5 after passing through a 2nd heating process.

(Configuration of Cap for Electronic Component According to First Embodiment of the Present Invention)
Hereinafter, a cap for an electronic component according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a cap according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is an enlarged view of a region B in FIG. 2 and is a diagram showing a configuration of a surface layer portion of the cap according to the first embodiment of the present invention.

  The cap 1 according to the first embodiment of the present invention has a dome-like shape on the surface of a so-called 42 alloy (nickel-iron alloy, nickel is 42% by weight) core 1 '. A brazing material 2 as shown in FIG. 3 is formed. In the brazing material 2, a tin layer 3, an indium layer 4, and a gold layer 5 are formed in this order from the core material 1 ′ side. That is, the brazing material 2 has an indium metal layer between gold and tin metal layers.

  The brazing material 2 is formed not only on the end sealing surface 1A of the core material 1 'but also over the entire surface of the core material 1'. The brazing material 2 has a metal layer configuration shown in FIG. 3 at various points on the surface of the core material 1 ′. The thickness of the tin layer 3 of the brazing material 2 at the end sealing surface 1A is 4 μm on average, the thickness of the indium layer 4 is 2.5 μm on average, and the thickness of the gold layer 5 is 13.5 μm on average. .

(Method for manufacturing cap for electronic component according to the first embodiment of the present invention)
The cap 1 is obtained by forming a tin layer 3, an indium layer 4, and a gold layer 5 in this order on the surface of the core material 1 'by a so-called barrel plating method.

(Usage of Cap for Electronic Component According to First Embodiment of the Present Invention)
FIG. 4 is a cross-sectional view showing a state in which the crystal vibration device (electronic component 10) is configured using the cap 1, similar to the cross-sectional view shown in FIG. First, an insulating substrate 6 made of alumina is prepared. Next, a stannous chloride aqueous solution is brought into contact with the surface of the insulating substrate 6 to be joined to the brazing material 2. Next, a catalyst application treatment is performed by bringing a palladium chloride aqueous solution into contact with the surface. Then, the surface subjected to the catalyst application treatment is masked with a resin mask so that the surface is exposed in a ring shape (substantially the same shape as the end sealing surface 1A portion of the core material 1 '). Then, electroless tin plating is performed on the ring-shaped exposed surface. Thereafter, the mask is dissolved and removed with an organic solvent.

  Next, the support member 7 and the crystal resonator 8 are disposed on the surface of the insulating substrate 6. The crystal resonator 8 is fixed to a support member 7 fixed on the surface of the insulating substrate 6 so that vibration is allowed in a cantilever state.

  An external terminal of the crystal unit 8 is formed on the surface of the insulating substrate 6 on the side where the crystal unit 8 is not disposed. However, the conductive path from the crystal resonator 8 to the external terminal is not shown.

  Next, using a pin member that can be pressed by a spring force, the cap 1 (end sealing surface 1A of the core material 1 ′) is pressed against the electroless tin plating layer forming portion of the insulating substrate 6 while the brazing material 2 and By melting and solidifying the electrolytic tin plating layer, the core material 1 ′ and the insulating substrate 6 are joined by the brazing material 2, and the electronic component 10 is manufactured.

The step of melting the brazing material 2 (hereinafter referred to as “heating step”) is performed at a temperature of about 280 ° C. to 350 ° C. for 1 minute in a reduced pressure atmosphere having a pressure of about 10 ⁻³ Pa to 10 ⁻⁴ Pa. Perform for about 60 minutes. Due to the heating process, the sealed space 9 shown in FIG.

(Configuration of Cap for Electronic Component According to Second Embodiment of the Present Invention)
An electronic component cap according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a sectional view showing the cap according to the second embodiment of the present invention in the same manner as FIG.

  The cap 11 according to the second embodiment of the present invention also has a so-called 42 alloy core 11 ′ having the same dome shape as the cap 1. The brazing material 12 is formed in a ring shape over almost the entire area of the end sealing surface 11A of the core material 11 '. The brazing material 12 is an alloy of gold and tin containing indium.

(Method for manufacturing a cap for an electronic component according to the second embodiment of the present invention)
The cap 11 is melted in a state where a ring-shaped low-melting-point metal layer made of an indium metal layer is in contact with the end sealing surface 11A of the core member 11 ′ between the metal layers of gold and tin, and thereafter The melted low melting point metal layer is solidified, and the brazing material 12 that is the solidified low melting point metal layer is fixed to the end sealing surface 11A.

  This manufacturing method will be described with reference to the drawings. FIG. 6 is a manufacturing flow diagram of the cap 11. FIG. 7 is a view showing a manufacturing process of the cap 11, and is an enlarged view of a portion of a region C in FIG. 5 before undergoing the second heating step. FIG. 8 is a view showing a manufacturing process of the cap 11 and is an enlarged view of a portion of a region C in FIG. 5 after the second heating step.

  First, an aqueous stannous chloride solution is brought into contact with the surface of an insulating substrate made of alumina. Next, a catalyst application treatment is performed by bringing a palladium chloride aqueous solution into contact therewith. Then, electroless nickel plating is performed on the insulating substrate surface to form a nickel layer 13 (P1). Next, the surface of the nickel layer 13 is masked with a resin mask so that the nickel layer 13 is exposed in a ring shape (substantially the same shape as the end sealing surface 11A portion of the core member 11 ').

  Next, gold is electrolytically plated on the exposed surface of the nickel layer 13 to form a gold layer 14 (P2). Next, indium is electroplated on the surface of the gold layer 14 to form an indium layer 15 (P3). Next, tin is electrolytically plated on the surface of the indium layer 15 to form a tin layer 16 (P4). The gold layer 14 has a thickness of 13.5 μm, the indium layer 15 has a thickness of 2.5 μm, and the tin layer 16 has a thickness of 4 μm. Thereafter, the mask is dissolved and removed with an organic solvent. As a result, a gold layer 14, an indium layer 15, and a tin layer 16 are stacked in this order on the nickel layer 13 on the surface of the insulating substrate.

  A step of melting the ring-shaped gold layer 14, indium layer 15 and tin layer 16 (these metal layers are low melting point metal layers) (hereinafter referred to as “second heating step”) is performed (P5). This second heating step is performed at a temperature of about 280 ° C. to 350 ° C. while pressing the end sealing surface 11A of the core material 11 ′ and the low melting point metal layer using a pin member that can be pressed by a spring force. It holds for about 1 to 60 minutes.

  In the second heating step, the gold layer 14, the indium layer 15 and the tin layer 16 constituting the low melting point metal layer are respectively melted to become the brazing material 12 as shown in FIG. It adheres to the end sealing surface 11A of the metal by metal bonding. In the second heating step, the nickel layer 13 is not melted and is bonded to the brazing material 12 by metal bonding.

  Then, the nickel layer 13 is dissolved and removed with an aqueous nitric acid solution (P6). By this process P6, the insulating substrate fixed to the nickel layer 13 can be removed from the cap 11. Here, the brazing material 12 hardly dissolves in the nitric acid aqueous solution. By this process P6, the manufacture of the cap 11 is completed. In addition, since the usage method of the cap 11 is the same as the usage method of the above-mentioned cap 1, description is abbreviate | omitted.

(Main effects obtained by the embodiment of the present invention)
The brazing materials 2 and 12 after the heating step or the second heating step are a ternary alloy of gold, tin and indium, or a binary alloy of gold and tin. Since these alloys are excellent in durability such as long-term oxidation resistance, the degree of vacuum of the sealed space 4 is hardly lowered due to the prolonged use period of the electronic component 10 (quartz crystal vibration device). Absent. Therefore, in the caps 1 and 11 for electronic parts according to the embodiment of the present invention, the brazing materials 2 and 12 have good durability.

  Further, since the brazing materials 2 and 12 hardly generate gasification components and the like even after the heating step or the second heating step (P5), it is possible to make it difficult to deteriorate the characteristics of the electronic component 10. Furthermore, the brazing materials 2 and 12 are obtained by laminating metal layers (plating layers), and can be easily manufactured without requiring a particularly difficult technique such as a plating technique.

  The brazing materials 2 and 12 that have undergone the heating process or the second heating process are joined to the end sealing surfaces 1A and 11A of the core materials 1 'and 11' with almost no gap and to the insulating substrate 6 with almost no gap. Therefore, the degree of vacuum of the sealed space 9 can be maintained high for a long period.

  As described above, it is difficult to arrange the tin layer 3 and the gold layer 5 and the gold layer 14 and the tin layer 16 in contact with each other by the plating technique. In addition, there is a technique for electrolytic plating of an alloy of gold and tin, but this is an extremely expensive technique and difficult to industrially use. However, the indium layers 4 and 15 can be interposed between the tin layer 3 and the gold layer 5 and between the gold layer 14 and the tin layer 16 by a plating technique, respectively. Therefore, the metal layer adjacent between the tin layer 3 and the gold layer 5 and between the gold layer 14 and the tin layer 16 can be formed.

  Then, through the heating step or the second heating step, alloying of the tin layer 3 and the gold layer 5, or alloying of the gold layer 14 and the tin layer 16, or the tin layer 3, the gold layer 5, and the indium layer 4 Alloying or alloying of the gold layer 14, the tin layer 16, and the indium layer 15 can be realized at low cost.

  If alloying of the tin layer 3, the gold layer 5, and the indium layer 4 or the alloying of the gold layer 14, the tin layer 16, and the indium layer 15 is realized, the alloy is the tin layer 3 and the gold layer 5. As in the case of the alloy of the above, or the alloy of the gold layer 14 and the tin layer 16, the sealing between the insulating substrate 6 and the caps 1 and 11 is ensured. The reason is that it has been proved that the brazing materials 2 and 12 actually ensure the sealing between the insulating substrate 6 and the caps 1 and 11.

  The formation of the brazing material 2 employs a barrel plating method. The brazing material 2 only needs to be formed at least in the portion of the end sealing surface 1A of the core material 1 ′, and the brazing material 2 formed in the other portion is difficult to be used for joining the insulating substrate 6 and the cap 1. it is conceivable that. The portion of the end sealing surface 1A is a portion that protrudes (becomes an edge) in the core material 1 ', and it is considered that the metal to be plated is easily deposited by an electrolytic plating method such as a barrel plating method. For this reason, it is considered that the plating efficiency (at least part of the end sealing surface 1A) is high, and a sufficiently thick plating layer (metal layer) can be obtained in a short time.

(Other forms)
The electronic component caps 1 and 11 and the manufacturing method thereof according to the embodiments of the present invention described above are examples of the preferred embodiments of the present invention, but are not limited thereto, and the gist of the present invention is changed. Various modifications can be made without departing from the scope.

  For example, the electronic component 10 is a crystal vibration device using the crystal resonator 8, but is not limited to this. For example, a so-called SAW (Surface Acoustic Wave) filter in which a piezoelectric element is sealed with an insulating substrate 6 and caps 1 and 11 or a light-emitting component in which an LED (light emitting diode) element is sealed with an insulating substrate 6 and caps 1 and 11 is used. Moreover, the caps 1 and 11 for electronic components which concern on embodiment of this invention can be used.

  The brazing materials 2 and 12 are manufactured through a process of forming a metal layer by a plating technique. However, one or more of the tin layers 3 and 16, the indium layers 4 and 15, and the gold layers 5 and 14 are metal layers formed by arrangement of metal powder or metal foil, sputtering, vapor deposition, or the like. Also good. The brazing material 2 has each metal layer formed by barrel plating, but other plating methods may be employed.

  In particular, since the indium layers 4 and 15 may be thin, it is easy to obtain a merit of forming by a sputtering method or a vapor deposition method. For example, when the cap 1 is manufactured, if the indium layer 4 is formed only on the end sealing surface 1A of the core material 1 ', the indium layer on the end sealing surface 1A is used in the subsequent gold plating by the barrel plating method. Since the gold layer 5 is formed only on 4, the gold layer 5 can be formed only in a necessary portion, and there is an advantage that the gold layer 5 does not need to be formed wastefully. In order to obtain the same merit, portions other than the end sealing surface 1A may be masked when the indium layer 4 is formed by the barrel plating method.

  Moreover, the thickness of the tin layers 3 and 16, the indium layers 4 and 15, and the gold layers 5 and 14 can be changed as appropriate. However, it has been found that the thickness of the indium layers 4 and 15 is preferably 0.1 μm or more, and more preferably 1 μm or more, by the inventors' investigation. Further, the thicknesses of the gold layer 14 and the tin layer 16 are gold: tin = A: B (A is 80 to 85, B is 20 to 15, and A + B as a ratio that tends to be an eutectic alloy when they are alloyed). = 100) is preferable.

  Moreover, although the nickel layer 13 is used when manufacturing the cap 11, the raw material can be changed suitably. For example, a copper layer or the like may be employed. However, the nickel layer 13 has an advantage that it can be easily removed by peeling or the like as compared with the copper layer. The nickel layer 13 is formed by electroless nickel plating. After the electroless nickel plating, an electrolytic nickel plating layer is formed on top of each other, and the electroless nickel plating layer and the electrolytic nickel plating layer are combined. The nickel layer 13 may be used. Moreover, it is good also as forming the metal layer which replaces the nickel layer 13 with the metallizing method on the surface of the ceramic insulating substrate. As the metal layer formed by the metallization method, for example, a metal layer such as tungsten, molybdenum, manganese, nickel plating layer or the like, or a molybdenum-manganese method, a molten titanium metallization method, or the like can be employed.

  Moreover, the lamination position of the tin layer 3 and the gold layer 5 or the lamination position of the gold layer 14 and the tin layer 16 can be reversed. Further, another plating layer (metal layer) may be formed between the tin layers 3 and 16 and the core materials 1 ′ and 11 ′.

  Further, in place of the indium layers 4 and 15, one or more plating layers (metal layers) selected from indium, bismuth, lead, zinc, and silver may be employed.

  The core materials 1 'and 11' are made of 42 alloy, but other materials, for example, made of Kovar (an alloy in which nickel and cobalt are mixed in iron) may be used. However, the 42 alloy has a thermal expansion coefficient close to that of alumina of the insulating substrate 6. Therefore, the combination of the insulating substrate 6 and the caps 1 and 11 can reduce the thermal stress applied to the brazing materials 2 and 12 even if there is a temperature change in the manufacturing process of the electronic component 10. The substrate 2 is made of alumina, but it may be made of other materials such as aluminum nitride. Furthermore, although the core materials 1 'and 11' have a dome shape, the shape can be changed as appropriate, and for example, a plate shape may be used.

Further, while pressing the core materials 1 ′ and 11 ′ against the brazing materials 2 and 12, the brazing materials 2 and 12 are melted in the heating process and the second heating process. Using a reflow furnace or the like, the core materials 1 ′, 11 ′ and the brazing materials 2, 12 may be brought into close contact with only the own weight of the core materials 1 ′, 11 ′. Furthermore, although the heating step and the second heating step are performed in a reduced pressure atmosphere having a pressure of about 10 ⁻³ Pa to 10 ⁻⁴ Pa, this condition can be changed as appropriate. Further, in the second heating process, the tin layer 16 of the low melting point metal layer is made to contact the end sealing surface 11A of the core material 11 ′, but the gold layer 14 is the end sealing surface 11A. You may carry out so that it may contact | abut.

  Further, when the caps 1 and 11 are used, the exposed surface of the insulating substrate 6 is subjected to electroless tin plating. Instead of the electroless tin plating, gold, indium, bismuth, lead, zinc, silver, copper, nickel For example, electroless plating of other metals may be performed. Furthermore, instead of forming the metal layer by electroless tin plating, the metal layer may be formed on the exposed surface of the insulating substrate 6 by the metallization method described above.

  Further, the ring-shaped low melting point metal layer (a laminate of the gold layer 14, the indium layer 15, and the tin layer 16) becomes the brazing material 12 by the second heating process, and peels off from the nickel layer 13 after adhering to the core material 11 ′. (Removal of the nickel layer 13). However, the ring-shaped low melting point metal layer is peeled off from the nickel layer 13 before being attached to the core material 11 ′ (dissolution removal of the nickel layer 13 with an aqueous nitric acid solution or mechanical peeling of the nickel layer 13), and then the core material 11. The brazing material 12 can be formed in contact with the end sealing surface 11A. In that case, the same step as the second heating step is performed such that the gold layer 14 (the tin layer 16 in the second heating step) of the low melting point metal layer is in contact with the end sealing surface 11A of the core material 11 ′. You can go.

1,11 cap 1 ', 11' core material 2,12 brazing material 3,16 tin layer (a kind of metal layer)
4,15 Indium layer (a kind of metal layer)
5,14 Gold layer (a kind of metal layer)
10 Electronic components

Claims (4)

In caps for electronic components,
A brazing material is formed on the surface of the core of the cap,
The cap for electronic parts, wherein the brazing material has one or more metal layers selected from indium, bismuth, lead, zinc, and silver between the metal layers of gold and tin. In the cap for electronic components of Claim 1,
One or more metal layers selected from indium, bismuth, lead, zinc, and silver have a thickness of 0.1 μm or more, and a cap for electronic parts. In caps for electronic components,
A brazing material is formed on the surface of the core of the cap,
A cap for electronic parts, wherein the brazing material includes an alloy of gold and tin containing one or more metals selected from indium, bismuth, lead, zinc, and silver. In the manufacturing method of caps for electronic components,
Forming a low melting point metal layer having at least one metal layer selected from indium, bismuth, lead, zinc, and silver between each metal layer of gold and tin;
The low melting point metal layer is melted in contact with the core of the cap, and then the melted low melting point metal layer is solidified,
A method of manufacturing a cap for an electronic component, wherein the solidified low melting point metal layer and the core material are fixed.