JP2001057400A - Metal cap insulating film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a method through which an insulating film is easily formed on the surface of a metal cap. SOLUTION: This method is carried out through such a manner where an electronic component sealing metal cap 1 is provided to cover and seal up an element 20 mounted on the surface of a board 10 where terminal electrodes 11 and 12 are formed, and an insulating film 2 is formed on the surface of a metal cap 1 through electrodeposition coating. It is preferable that an insulating film is formed through an electrodeposition coating process holding the metal cap 1 with a jig and keeping it electrically conductive.

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. 12 is a sectional view showing an example of a conventional electronic component sealed by such a cap. FIG.
In the conventional electronic component shown in FIG.
0 is used. This is because the cap 40 is attached 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.

[0004] As the insulating cap 40, a ceramic cap, a resin cap, or the like 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. 13, an insulating layer 41 is formed on the substrate 10 on which the metal cap 42 is mounted and the terminal electrodes 11 and 12.
Is formed, and a cap 42 is placed on the insulating layer 41. In FIG. 13, 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 Patent Application Laid-Open No. 6-132762 discloses a metal cap having an insulating layer provided on the inner surface. In such a metal cap, an end in contact with the substrate is bent outward, and an inner surface thereof is formed so as to be in contact with the terminal electrode, and an insulating layer provided on the inner surface is in contact with the terminal electrode. Since the insulating layer is interposed between the metal cap and the terminal electrode in this manner, a short circuit between the terminal electrodes can be prevented. The gazette does not describe a specific method of forming the insulating layer, but it is presumed that the insulating layer is pre-coated in a state of the plate material before forming the metal cap, and the pre-coated plate material is formed into a cap shape. Seem. In such a metal cap, it is necessary to bend its end outward in order to locate the insulating layer in a position in contact with the terminal electrode. In addition, during such bending, the insulating layer may be peeled off, resulting in insufficient insulation.

In some cases, an insulating layer is also provided outside the metal cap to maintain electrical insulation from other components when mounted on a circuit board. Only the disclosed metal cap is disclosed, and there is no disclosure of a method of providing an insulating layer outside the metal cap.

An object of the present invention is to provide a method for forming an insulating film of a metal cap, which can easily form an insulating film in a state of being formed into a cap shape.

[0011]

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. This is a method of forming an insulating film for electrically insulating between a terminal electrode and a metal cap, and is characterized in that the insulating film is formed on the surface of the metal cap by electrodeposition coating.

According to the present invention, an insulating film can be formed on a surface of a metal cap in a state where the insulating film is formed into a cap shape. Therefore, regardless of the cap shape, the insulating film can be formed on the surface of the portion that comes into contact with the terminal electrode when it is mounted on the substrate surface. If such a metal cap is used, it can be mounted and sealed on the substrate surface using an adhesive or the like as it is.

As the electrodeposition coating in the present invention, a conventional general electrodeposition coating method can be adopted. A cationic electrodeposition coating or an anion type electrodeposition coating is used, and a metal cap is used as a cathode or an anode. Can be electrodeposited.

In one preferred embodiment according to the present invention, a state in which a conductive double-sided tape is stuck on a conductive support plate, and a metal cap is stuck on the conductive double-sided tape to make it electrically conductive. It is characterized in that it is supported by an electrodeposition coating. According to such a method, a large number of arranged metal caps can be simultaneously adhered to the conductive double-sided tape, supported and fixed, and the large number of metal caps can be simultaneously electrodeposited efficiently.

Another preferred embodiment according to the present invention is characterized in that the electrodeposition coating is performed with the metal cap held by a jig and electrically connected. According to such a method, the metal cap can be held and fixed with a simple jig.

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, and is in contact with at least the terminal electrode. An insulating film formed by electrodeposition coating is formed on the surface of the portion.

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 on at least the surface in contact with the terminal electrode, even if the metal cap 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 is formed Can ensure the insulation properties of the substrate. Therefore, it is possible to efficiently manufacture a low-profile electronic component.

[0018]

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
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 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. An insulating film 2 is formed on the surface of the metal cap 1. This insulating film 2 is an insulating film formed by electrodepositing the surface of the metal cap 1. The thickness of the insulating film is 3 to 30 μm
It is preferred that it is about.

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 places 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 excluding 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. 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 sectional view for explaining a method of forming an insulating film in the first embodiment according to the present invention. A conductive double-sided tape 31 is attached on a conductive support plate 30 made of a metal plate or the like. The conductive double-sided tape 31 is a double-sided tape provided with conductivity by containing, for example, metal powder or carbon black. A plurality of metal caps 1 are stuck on the conductive double-sided tape 31. The conductive support plate 30 is held by a conductive holder 32 made of metal or the like.

FIG. 8 is a sectional view showing a support state of the metal cap 1 shown in FIG. As shown in FIG. 8, the metal cap 1 is stuck on the upper surface so as to adhere to the conductive double-sided tape 31. Metal cap 1
It is electrically connected to the conductive support plate 30 via the conductive double-sided tape 31. Therefore, by using the conductive support plate 30 as a cathode or an anode via the holder 32, the metal cap 1 can be used as a cathode or an anode.

While the metal cap 1 is supported as described above, the metal cap 1 is immersed in an electrodeposition paint, and the metal cap 1 is used as a cathode or an anode, so that the metal cap 1 is electrodeposited on the exposed surface. Thus, an insulating film can be formed by electrodeposition coating. In the supporting method of the present embodiment, the upper surface of the metal cap 1 is
No insulating film is formed on the upper surface of the metal cap 1. Therefore, the insulating film pattern of the embodiment as shown in FIG. 3 can be formed.

FIG. 9 is a front view for explaining an insulating film forming method in the second embodiment according to the present invention. FIG. 10 is a cross-sectional view showing a support state of the metal cap shown in FIG.

Referring to FIGS. 9 and 10, a conductive support plate 33 made of a metal plate or the like has a laterally extending protrusion 33a as shown in FIG. A conductive double-sided tape 34 is attached on the protruding portion 33a. Similar to the conductive double-sided tape 31 shown in FIGS. 7 and 8, the conductive double-sided tape 34 has conductivity by containing, for example, metal powder or carbon black. The metal cap 1 is attached on the conductive double-sided tape 34. As shown in FIG. 10, the metal cap 1 is attached so as to adhere to the conductive double-sided tape 34 at the bottom surface. Conductive support plate 33
Are held by a conductive holder 35 made of metal or the like.

The metal cap 1 is made of a conductive double-sided tape 34
Are electrically connected to the conductive support plate 33 through the. Therefore, by using the conductive support plate 33 as a cathode or an anode via the holder 35, the metal cap 1 can be used as a cathode or an anode. In such a supported state, the metal cap 1 is immersed in an electrodeposition paint and the metal cap 1 is used as a cathode or an anode, so that the surface of the metal cap 1 can be electrodeposited.

Since the electrodeposition coating is easy to cover, it can be applied not only to the outer surface of the metal cap 1 but also to the inner surface. However, since the portion to be bonded to the conductive double-sided tape 34 is not coated, the metal cap 1
No coating film is formed at the center of the bottom surface of. Accordingly, the pattern of the insulating film on the bottom surface of the metal cap 1 is in a state as shown in FIG. Care must be taken so that a region where such an insulating film is not formed does not overlap with a region in contact with the terminal region.

FIG. 11 is a sectional view showing a method of forming an insulating film in a third embodiment according to the present invention. In this embodiment, a spring-like member 37 made of a conductive material such as metal is provided on a conductive support plate 36 made of a metal plate or the like, and the metal cap 1 is pushed and supported so as to be sandwiched between the spring-like members 37. The metal cap 1 is electrically connected to the conductive support plate 36 via the spring member 37. Therefore, by using the conductive support plate 36 as a cathode or an anode, the metal cap 1 can be used as a cathode or an anode.

In such a supported state, the metal cap 1 is immersed in an electrodeposition paint, and the metal cap 1 is used as a cathode or an anode, so that an insulating film made of an electrodeposition coating film is formed on the exposed surface of the metal cap 1. be able to. According to the present embodiment, an insulating film can be formed on the surface of the metal cap 1 other than the portion where the spring-like member 37 and the metal cap 1 are in contact.

As described above, according to the present invention, an insulating film can be formed in a state of being formed into a cap shape. Therefore, it is not necessary to perform bending or the like after forming the insulating film as in the related art, and a good insulating film can be formed on the surface in contact with the terminal electrode.

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. Is also good.

[0040]

According to the method for forming an insulating film of the present invention, the insulating film can be easily formed in a state of being formed into a cap shape. Therefore, a good insulating film can be formed on the surface of the portion in contact with the terminal electrode. Since such a metal cap can be directly attached to a substrate using 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 front view showing a support state of the metal cap in one of the preferred embodiments according to the present invention.

FIG. 8 is a sectional view showing a support state of the metal cap shown in FIG. 7;

FIG. 9 is a front view showing a support state of a metal cap in another preferred embodiment according to the present invention.

FIG. 10 is a sectional view showing a support state of the metal cap shown in FIG. 9;

FIG. 11 is a cross-sectional view showing a support state of a metal cap in still another preferred embodiment according to the present invention.

FIG. 12 is a sectional view showing an example of a conventional electronic component.

FIG. 13 is a perspective view showing another example of a conventional electronic component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal cap 2 ... Insulating film 10 ... Substrate 11-13 ... Terminal electrode 20 ... Element 21, 22 ... Solder 30, 33 ... Conductive support plate 31, 34 ... Conductive double-sided tape 32, 35 ... Holder

Continued on the front page (72) Inventor Shoichi Kawabata 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (reference) 5F058 AA10 AB05 AD01 AF10 AH10 BA20 BB05 BF42 BF80 BJ10

Claims (4)

[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. A method for forming an insulating film for electrically insulating between the metal cap and the metal cap, wherein an insulating film is formed on the surface of the metal cap by electrodeposition coating. 2. A method in which a conductive double-sided tape is stuck on a conductive support plate, a metal cap is stuck on the conductive double-sided tape, and the conductive double-sided tape is supported in an electrically conductive state. The method for forming an insulating film of a metal cap according to claim 1, wherein: 3. The method for forming an insulating film on a metal cap according to claim 1, wherein the electrodeposition coating is performed while the metal cap is held by a jig and is electrically connected. 4. A metal cap for sealing an electronic component mounted on a surface of a substrate for covering and sealing an element mounted on the surface of the substrate on which the terminal electrode is formed, at least a portion in contact with the terminal electrode. A metal cap for sealing electronic parts, characterized in that an insulating film is formed on the surface of the substrate by electrodeposition coating.