JP2001057399A - Metal cap insulating film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a method which is capable of easily insulating the terminal electrode of a board from a metal cap. SOLUTION: This method is carried out through such a manner where an electronic component sealing metal cap 1 is mounted on the surface of a board 10 so as to cover and seal up an element 20 mounted on the surface of the board 10 where terminal electrodes 11 and 12 are provided, and an insulating film is formed on the metal cap 1 so as to insulate the terminal electrodes 11 and 12 from the metal cap 1. At this point, the metal cap 1 is made of aluminum or its alloy and formed into a cap shape, and the cap is subjected to an anodizing treatment, by which an insulating film 2 is formed on the surface of the metal cap 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an insulating film on a surface of a metal cap for sealing electronic parts for covering and sealing elements such as piezoelectric ceramic elements mounted on the surface of a substrate such as a capacitor substrate. It is about the method.

[0002]

2. Description of the Related Art In a chip-type electronic component in which an element such as a piezoelectric resonance element is mounted on a substrate, a piezoelectric vibrating portion vibrates. Is used. Specifically, after mounting the element on the substrate surface,
A cap is mounted on the substrate surface to cover and seal the device.

FIG. 13 is a cross-sectional view showing an example of a conventional electronic component sealed with such a cap. FIG.
In the conventional electronic component shown in FIG.
0 is used. This is because the cap 30 is mounted on the terminal electrodes 11 and 12 formed on the substrate 10, so that insulation is required to prevent a short circuit between the terminal electrodes 11 and 12. . An element 20 such as a piezoelectric resonance element is mounted on the upper surface side of the substrate 10. The element 20 is joined to the terminal electrode 11 by solder 21, and is joined to the terminal electrode 12 by solder 22. A terminal electrode 13 for forming a capacitor between the terminal electrodes 11 and 12 is provided between the terminal electrodes 11 and 12 on the lower surface side of the substrate 10.

As the insulating cap 30, a ceramic cap or a resin cap is used. However, these caps need to have a thickness of 0.25 mm or more in consideration of moldability, so that a reduction in height cannot be achieved, and there is a problem that the substrate area increases.

In order to reduce the height and increase the degree of integration of the circuit board, it is preferable to use a metal cap as the cap. However, if the metal cap is directly mounted on the substrate, a short circuit occurs between the terminal electrodes as described above.

In order to prevent such a short circuit between the terminal electrodes, as shown in FIG. 14, an insulating layer 31 is formed on the substrate 10 on which the metal cap 32 is mounted and the terminal electrodes 11 and 12.
Is formed, and a cap 32 is placed on the insulating layer 31. In FIG. 14, elements such as a piezoelectric resonance element mounted on the substrate 10 are not shown.

According to such a method, a metal cap can be used, so that the height can be reduced. However, as electronic components become smaller, it is necessary to form an insulating layer on a substrate with high precision. The problem arises that it becomes difficult.

Japanese Utility Model Application Laid-Open No. Sho 62-158828 and JP-A-8-204449 disclose electronic components using a metal cap formed by using an aluminum plate having an anodic oxide film formed on its surface. I have.
However, since these metal caps have been subjected to anodizing treatment in the state of a plate material, when formed into a cap shape, an anodic oxide film is not formed on the end face of the substrate that contacts the terminal electrode, and the terminal It is not possible to prevent a short circuit between the electrodes.

It is an object of the present invention to provide a method for forming an insulating film of a metal cap, which can realize insulation between a terminal electrode of a substrate and a metal cap by a simple method.

[0010]

According to the present invention, there is provided a metal cap for electronic component sealing which is mounted on a substrate surface for covering and sealing an element mounted on the substrate surface on which a terminal electrode is formed. A method of forming an insulating film for electrically insulating between a terminal electrode and a metal cap.The metal cap is made of aluminum or an alloy thereof, and is subjected to anodizing treatment in a state of being formed in a cap shape. In addition, an insulating film is formed on the surface of the metal cap.

According to the present invention, since the anodizing treatment is performed in the state of being formed into a cap shape, when it is mounted on the substrate surface, the insulating film by the anodizing treatment is formed on the surface in contact with the terminal electrode. Can be formed. Therefore, if such a metal cap is used, it can be mounted and sealed on the substrate surface as it is using an adhesive or the like.

The anodic oxidation treatment in the present invention can be performed under general anodic oxidation treatment conditions, and an oxide film can be formed by electrolysis using a metal cap as an anode. As the electrolyte, a common acidic electrolyte such as sulfuric acid, oxalic acid, and chromic acid can be used.

In one preferred embodiment according to the present invention, the anodizing treatment is performed while the metal cap is held by a jig and is electrically connected. A conductive jig is used as the jig, and is electrically connected to the metal cap, and electrolytic treatment is performed using the metal cap as an anode. This method is suitable for the case where the metal caps are individually separated and are in a disjointed state.

In another preferred embodiment according to the present invention, the anodizing treatment is performed in a state where the metal cap is connected as a hoop. The state of the hoop is a state after the plate material is punched out and formed into a cap shape, and the plate material and the cap are partially connected.

In such a hoop state, anodic oxidation treatment can be continuously performed. That is, the hoop wound around one roll or the like is pulled out, sent out to an anodizing treatment bath, and after the anodizing treatment, the hoop can be wound around the other roll or the like to continuously perform anodizing treatment. In this case, the contact for electrically conducting the hoop can be moved together with the movement of the hoop to maintain the conduction state.

Further, the hoop cut in predetermined units may be immersed in an anodizing bath to perform anodizing. In this case, the portion holding the hoop can be electrically connected as a contact.

The metal cap of the present invention is a metal cap for sealing electronic components mounted on a substrate to cover and seal an element mounted on the surface of the substrate on which the terminal electrode is formed, wherein the metal cap is made of aluminum or aluminum. It is characterized in that an insulating film is formed by anodic oxidation treatment on at least the surface of the portion made of the alloy and in contact with the terminal electrode.

The metal cap of the present invention is a cap that can be formed by the above-described method of forming an insulating film of the present invention. Since the metal cap of the present invention has an insulating film formed at least on the surface in contact with the terminal electrode, even if it is mounted on the substrate surface using an adhesive or the like as it is, the gap between the terminal electrode of the substrate and the metal cap Insulation can be ensured. Therefore, it is possible to efficiently manufacture a low-profile electronic component.

[0019]

FIG. 1 is a cross-sectional view showing an electronic component using a metal cap on which an insulating film is formed according to one embodiment of the present invention.

A terminal electrode 11 and a terminal electrode 1 are provided on an end surface, an upper surface, and a lower surface of both ends of a substrate 10 such as a dielectric substrate.
2 are formed. Terminal electrodes 13 are further formed in the center of the lower surface of the substrate 10, and capacitors are respectively formed between the terminal electrodes 11 and 13 and between the terminal electrodes 12 and 13. Separate capacitors are formed between the terminal electrodes 11 and 12.
In the substrate 10, an internal electrode whose end is in contact with the terminal electrode 11 or the terminal electrode 12 may be formed, and a capacitor may be formed between such internal electrodes.

An element 20 such as a piezoelectric resonance element is mounted on the upper surface side of the substrate. One end of the element 20 is solder 21
To the terminal electrode 11 and the other end is solder 2
2 are joined to the terminal electrode 12. Further, a metal cap 1 is attached to the upper surface side of the substrate 10 so as to cover and seal the element 20. The metal cap 1 is made of aluminum or its alloy. An insulating film 2 is formed on the surface of the metal cap 1. This insulating film 2 is an insulating film formed by subjecting the surface of the metal cap 1 to an anodic oxidation treatment. The thickness of the insulating film is preferably about 3 to 30 μm.

As shown in FIG. 1, the terminal electrodes 11 and 12
Since the insulating film 2 is interposed between the metal cap 1 and the metal cap 1, the metal cap 1 does not come into direct contact with the terminal electrode 11 or 12, and good insulation is secured. The metal cap 1 can be bonded onto the substrate 10 using a suitable adhesive or the like.

FIGS. 2 to 6 are views showing examples of locations where an insulating film is formed on the surface of the metal cap. In each figure, (a) is a perspective view, (b) is a cross-sectional view taken along the line AA shown in (a), and (c) is the bottom surface of the metal cap, that is, the surface in contact with the substrate. Is shown. In each drawing, a portion where an insulating film is formed is hatched.

As shown in FIG. 2, the insulating film 12 may be formed on the entire surface of the metal cap 1. In the embodiment shown in FIG. 2, the insulating film 2 is formed on all of the outer and inner surfaces of the metal cap 1 and the bottom surface which is in contact with the metal cap 1 when it is attached to the substrate. By providing the insulating film 2 on the entire surface of the metal cap 1 as described above, when this electronic component is mounted on a circuit board, electrical insulation can be maintained even when the electronic component comes into contact with other components, and the electrical characteristics deteriorate. Can be prevented. Since the insulating film 2 is also formed on the inner surface of the metal cap 1,
Insulation with elements, solder, and the like inside can be maintained.

In the embodiment shown in FIG. 3, an insulating film 2 is formed on the surface of the metal cap 1 except for the outer upper surface. When the insulating film is not formed on the outer upper surface of the metal cap 1 as described above, it is possible to check whether the metal cap and the terminal electrode are insulated by using this portion.

In the embodiment shown in FIG. 4, a portion where the insulating film 2 is not formed is provided below the center of the side surface of the metal cap 1. In this portion, the insulating film 2 is not formed even on the bottom surface of the metal cap 1. Care must be taken that the region where such an insulating film is not formed is a region that does not contact the terminal electrode. In addition, such an insulating film pattern of the metal cap can be manufactured, for example, in the case of anodic oxidation in a hoop state as described later. By connecting the ground to a region where the insulating film 2 is not formed, the metal cap 1 can be provided with a shielding function.

In the embodiment shown in FIG. 5, a region where the insulating film 2 is not formed is provided at the center of the side surface. In such a metal cap as well, a region where the insulating film 2 is not formed can be connected to the ground to provide the metal cap 1 with a shielding function.

In the embodiment shown in FIG. 6, the insulating film 2 is formed only on the lower end of the metal cap 1. The insulating film 2 is formed outside and inside the lower end of the metal cap 1 and on the bottom surface. Also in these metal caps, a portion where the insulating film 2 is not formed can be connected to the ground to provide a shielding function.

As described above, the region where the insulating film is formed in the present invention is not particularly limited, as long as the insulating film is provided at least on the surface in contact with the terminal electrode.

FIG. 7 is a cross-sectional view for explaining a method of forming an insulating film in the first embodiment according to the present invention. In the present embodiment, the metal cap 1 is electrically conducted while being held by the jig 3, and anodization is performed using the metal cap 1 as an anode. As the jig 3, a metal spring-like member that can fix the metal cap 1 from the inside can be used. Anodizing treatment in such a state,
It is suitable when the metal cap 1 is separated and in a disjointed state.

FIG. 8 is a perspective view showing a state of the anodic oxidation treatment in the second embodiment according to the present invention. In the present embodiment, the cap 1 is connected to and connected to the hoop 4. Such a hoop 4 is in a state after the plate material has been punched and formed into a cap shape and before the cap 1 is removed from the punched portion. Such a hoop 4
For example, in order to electrically conduct the metal cap 1 in (1), for example, a conduction roll 5 as shown in FIG.

FIG. 9 shows an embodiment in which the hoop 4 in the state shown in FIG. 8 is continuously anodized. The hoop 4 is wound around a delivery roll 6, from which the hoop 4 is delivered to an anodizing bath 8. The hoop 4 is electrically conducted by being in contact with the conduction roll 5. In the anodizing bath 8, the hoop 4
That is, the metal cap 1 is anodized, and an oxide film is formed on the surface. Hoop after anodizing 4
Is taken up by a take-up roll 7. In this manner, the metal cap 1 can be continuously anodized in the state of the hoop 4.

FIG. 10 is a front view showing a state of the anodic oxidation treatment in the third embodiment according to the present invention. In the present embodiment, the hoop 4 cut into predetermined units is used, and the hoop 4 is immersed in an anodizing bath to perform anodizing. That is, the hoop 4 is anodized in a batch mode. The hoop 4 is held by a holder 9 that maintains electrical continuity. In this state, the hoop 4 is immersed in an anodizing bath, anodized, and an insulating film made of an oxide film is provided on the surface.

After performing the anodic oxidation treatment in the state of the hoop as described above, the metal cap 1 is removed from the hoop 4.
At this time, it is cut off at the connection point in the hoop 4,
No insulating film is formed at the location where the separation was performed. Therefore, a metal cap having an insulating film pattern as shown in FIG. 4 can be manufactured.

FIG. 11 is a cross-sectional view showing a state in which cuts 4a and 4b are formed in a connection portion between the hoop 4 and the metal cap 1. As shown in FIG. The cuts 4a and 4
By forming b and reducing the thickness of the connecting portion in advance, the metal cap 1 can be easily removed from the hoop 4 after the anodizing treatment.

FIG. 12 shows a state after the anodic oxidation treatment. As shown in FIG. 12, the insulating film 2, which is an oxide film, is formed on the front and back surfaces of the hoop 4, respectively. Since the insulating film 2 is formed with a substantially uniform thickness as a whole, the thickness of the metal plate becomes extremely thin at the portions where the cuts 4a and 4b are formed. Therefore, the metal cap 1 can be removed with a weak external force.

The cuts 4a and 4b formed in FIG. 11 can be formed to have a depth, for example, about half the thickness of the metal plate. In the above embodiments, a substrate such as a dielectric substrate has been described as an example of a substrate on which elements are mounted. However, the present invention is not limited to this, and for example, an insulating substrate may be used.

[0038]

According to the method of forming an insulating film of the present invention, an anodizing treatment is performed in a state of being formed into a cap shape, so that an insulating film is formed on the surface in contact with the terminal electrode by the anodizing treatment. Can be. Since such a metal cap can be directly attached to a substrate with an adhesive or the like, an electronic component whose height can be reduced can be efficiently manufactured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an electronic component using a metal cap having an insulating film formed according to the present invention.

FIGS. 2A and 2B are views showing a metal cap according to an embodiment of the present invention, wherein FIG. 2A is a perspective view and FIG.
Sectional drawing along a line, (c) is a bottom view.

3A and 3B are views showing a metal cap of another embodiment according to the present invention, wherein FIG. 3A is a perspective view, and FIG.
Sectional drawing along line A, (c) is a bottom view.

4A and 4B are diagrams showing a metal cap of still another embodiment according to the present invention, wherein FIG. 4A is a perspective view, FIG. 4B is a cross-sectional view taken along line AA shown in FIG. Bottom view.

5A and 5B are views showing a metal cap of still another embodiment according to the present invention, wherein FIG. 5A is a perspective view, FIG. 5B is a cross-sectional view taken along the line AA shown in FIG. Bottom view.

FIGS. 6A and 6B are views showing a metal cap of still another embodiment according to the present invention, wherein FIG. 6A is a perspective view, FIG. 6B is a cross-sectional view taken along the line AA shown in FIG. Bottom view.

FIG. 7 is a cross-sectional view showing a holding state of the metal cap 1 at the time of anodizing treatment in one of preferred embodiments according to the present invention.

FIG. 8 is a perspective view for explaining another preferred embodiment according to the present invention.

FIG. 9 is a sectional view for explaining another preferred embodiment according to the present invention.

FIG. 10 is a front view for explaining still another preferred embodiment according to the present invention.

FIG. 11 is a cross-sectional view showing a state where a cut is formed in a connection portion between the hoop and the metal cap 1 in the present invention.

FIG. 12 is a sectional view showing a state after anodizing the hoop shown in FIG. 11;

FIG. 13 is a sectional view showing an example of a conventional electronic component.

FIG. 14 is a perspective view showing another example of a conventional electronic component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal cap 2 ... Insulating film 3 ... Jig 4 ... Hoop 5 ... Conducting roll 6 ... Sending roll 7 ... Winding roll 8 ... Anodizing bath 9 ... Holder 10 ... Substrate 11-13 ... Terminal electrode 20 ... Element 21, 22, ... solder

Claims (6)

[Claims] The terminal electrode and the metal cap are provided on a surface of a metal cap for electronic component sealing mounted on the substrate surface to cover and seal an element mounted on the substrate surface on which the terminal electrode is formed. Forming an insulating film for electrically insulating between the metal cap and the metal cap, the metal cap is made of aluminum or an alloy thereof, and anodized in a state of being formed in a cap shape, the metal cap A method for forming an insulating film on a metal cap, comprising forming an insulating film on a surface of the cap. 2. The method for forming an insulating film on a metal cap according to claim 1, wherein the anodizing treatment is performed in a state where the metal cap is held by a jig and is electrically connected. 3. The metal according to claim 1, wherein the anodic oxidation treatment is performed in a state of a hoop partially connected to the plate after the plate is punched and formed into a cap shape. A method for forming an insulating film of a cap. 4. The formation of an insulating film on a metal cap according to claim 3, wherein the hoop is sent out to an anodizing treatment bath, and the hoop after the anodizing treatment is wound up to perform anodizing treatment continuously. Method. 5. The method according to claim 3, wherein the hoop cut in predetermined units is immersed in an anodizing bath to perform anodizing. 6. A metal cap for sealing electronic components mounted on a surface of a substrate for covering and sealing an element mounted on the surface of the substrate on which a terminal electrode is formed, wherein the metal cap is made of aluminum or the same. A metal cap for electronic component sealing, wherein an insulating film is formed by an anodizing treatment at least on a surface of a portion which is in contact with the terminal electrode, which is made of an alloy.