KR20150115665A

KR20150115665A - Electronic component

Info

Publication number: KR20150115665A
Application number: KR1020150047170A
Authority: KR
Inventors: 다카야 사카모토; 히데카즈 가토; 히데타카 사토; 구니아키 스즈키; 요시나오 다니구치; 마사카즈 가토
Original assignee: 알프스 덴키 가부시키가이샤
Priority date: 2014-04-04
Filing date: 2015-04-03
Publication date: 2015-10-14
Also published as: CN104973560A; KR101730997B1; CN104973560B; JP2015201495A

Abstract

An electronic component capable of insulating a surface of a metal conductor exposed in an opening formed by an insert molding method.
The molten resin is injected in the mold 20 while the plate portion 11 of the metal conductor is supported by the support protrusion 21 to form the bottom wall portion 3a of the base body 3. [ Therefore, after the molding, the opening portion 3d is formed in the bottom wall portion 3a. The surface 11a of the plate portion 11 exposed in the inside of the opening 3d is covered with the insulating resin layer 31. [ Therefore, even if water or the like intrudes into the opening portion 3d, it can be prevented that the plate portion 11 is electrically short-circuited.

Description

[0001] ELECTRONIC COMPONENT [

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic part in which a metal conductor is inserted into a base made of a synthetic resin constituting a housing or the like.

A gas made of a synthetic resin in which a metal conductor is embedded is often used for a housing or a case of an electronic component, and this kind of gas is manufactured by a so-called insert molding method.

In the electronic component described in Patent Document 1, a lid body in which a metal terminal is embedded by insert molding, and a storage chamber are formed by a housing. In the insert molding process for manufacturing the lid, the resin is injection-molded in the mold with the terminal being pressed by the pressing pin in the mold, so that the position of the terminal in the mold is prevented from being displaced by the resin pressure. In this molding step, a pin hole corresponding to the shape of the pressing pin is formed on the lid body after molding.

Japanese Patent Application Laid-Open No. 10-55906

In the lid body formed by insert molding as described in Patent Document 1, a part of the metal terminal is exposed in the pin hole. Therefore, when water enters the pin hole, water may come into contact with the terminal to cause a short circuit, and if moisture enters the plurality of pin holes at the same time, there is a possibility that the metal terminals are short-circuited. Particularly, even when a small amount of water adheres to an electronic component having a minute dimension, the moisture tends to enter the plurality of pin holes at the same time, and the problem of short-circuiting tends to occur.

As a countermeasure for preventing the short circuit, it is conceivable to insulate the surface of the terminal by filling the inside of the pin hole with an insulating resin such as an adhesive after the lid body is formed. In this measure, however, The number of work processes is increased. In addition, in the case of a minute electronic component, since the opening dimension of the fin hole becomes very small, it is difficult to fill the pin hole with the insulating resin.

It is an object of the present invention to provide an electronic part capable of insulating a metal conductor inside an opening formed by a so-called insert molding process.

The present invention relates to an electronic part in which a metallic conductor is embedded in a base made of a synthetic resin,

Wherein an opening is formed in the base to reach a surface of the metal conductor and a surface of the metal conductor exposed in the opening is covered with an insulating resin layer.

In the present invention, the base is insert-molded, and the opening is formed by a support protrusion for supporting the metal conductor in the metal mold.

In the electronic component of the present invention, since the insulating resin layer is formed on the surface of the metal conductor, the surface of the metal conductor exposed inside the opening can be insulated. Further, after the base body is formed, an operation of supplying an insulating material such as an adhesive to the opening portion becomes unnecessary.

In the electronic component of the present invention, it is preferable that the surface of the metal conductor on which the insulating resin layer is formed is activated.

In the above configuration, the insulating resin layer is firmly fixed to the surface of the metal conductor.

In the present invention, it is preferable that the insulating resin layer is formed continuously from a portion exposed in the opening portion to a peripheral region covered with a gas.

The insulating resin layer formed on the surface of the metal conductor exposed to the inside of the opening portion continuously extends around the insulating resin layer and is disposed between the base and the metal conductor at the peripheral portion, It is hard to cause peeling or the like on the ground layer.

In the present invention, it is preferable that the opening has a portion gradually increasing in cross-sectional area toward the outside of the base from an inner end located on the insulating resin layer side.

In the above configuration, the edges of the support protrusions touching the metal conductor by insert molding disappear, and the insulating resin layer is less likely to be damaged at the edge portions.

INDUSTRIAL APPLICABILITY The present invention can prevent the metal conductor from being short-circuited by moisture or the like by insulating the surface of the metal conductor even if the opening is formed in the base by the insert molding process and the metal conductor is exposed in the structure have. Further, after the base body is formed, an operation of supplying an insulating material such as an adhesive to the opening portion becomes unnecessary.

1 is a perspective view showing an example of an electronic component manufactured by the manufacturing method of the present invention.
Fig. 2 is a cross-sectional view of the electronic component shown in Fig. 1 taken along the line II-II.
3 is an enlarged cross-sectional view showing part of FIG.
4 is a partially enlarged cross-sectional view of part IV of Fig.
5 is a partially enlarged cross-sectional view of part V of Fig.
6 is a partially enlarged cross-sectional view of part VI of Fig.
7 is a diagram showing the properties of the adhesive resin layer during the heat treatment.
8 is a cross-sectional photograph showing a junction between the metal conductor and the base body.

The electronic component 1 shown in Figs. 1 and 2 has a housing 2. The housing (2) is composed of a base (3) and a cover body (4). The lid body (4) is made of a synthetic resin material capable of bending deformation. The base 3 is formed of a synthetic resin and has a bottom wall portion 3a and four side wall portions 3b. The base body 3 has an opening surrounded by the upper end of the side wall portion 3b and the opening is closed by the cover body 4 so that the housing space 5, which is a closed space, Respectively. The housing 2 has a minute structure, a cube shape or a rectangular parallelepiped shape, and the maximum value of one side is formed to be 5 mm or less, more specifically 2 mm or less.

The detecting element 6 is housed in the housing space 5 of the housing 2. [ The detecting element 6 is a MEMS (Micro Electro Mechanical Systems) element, and is composed mainly of a silicon substrate. The detecting element 6 is a force sensor, and the deformed portion is warped by an external pressure, and the amount of deflection is detected by the change of the electric charge. The lid body 4 is deformed by the external pressure and the change in the internal pressure of the storage space 5 at that time is detected by the detecting element 6 do. Therefore, the storage space 5 needs to be an airtight space shielded from the outside air.

As shown in Fig. 1, Fig. 2 and Fig. 3, four metal conductors 10 are buried in the bottom wall 3a of the base body 3 by so-called insert molding.

As shown in Figs. 2 and 3, each of the metal conductors 10 has a first plate portion 11 and a second plate portion 12. As shown in Fig. The first plate portion 11 extends parallel to the bottom surface 3c of the bottom wall portion 3a and the second plate portion 12 is bent at a substantially right angle from the first plate portion 11, 3c extending vertically. The boundary between the first plate portion 11 and the second plate portion 12 is the bent portion 15. An external terminal portion 14 continuous to the first plate portion 11 and an internal terminal portion 13 continuous to the second plate portion 12 are formed integrally with the metal conductor 10. The internal terminal portion 13 is bent at a substantially right angle from the second plate portion 12 and extends substantially parallel to the bottom surface 3c.

The first and second plate portions 11 and 12 are buried in the bottom wall portion 3a of the base body 3 in the metal conductor 10. The external terminal portion 14 protrudes laterally of the base body 3. The other portions of the internal terminal portion 13 are buried in the bottom wall portion 3a in a state in which the upper surface 13b thereof is exposed in the accommodating space 5. [ The upper surface 13b of the internal terminal portions 13 of the four metal conductors 10 is exposed in the interior of the storage space 5. [ Electrodes are formed at four locations on the detecting element 6, and each electrode and each internal terminal portion 13 are connected by a solder fillet 7 in a one-to-one relationship.

2 and 3, in the bottom wall portion 3a of the base body 3, the first opening portion 3d extends from the bottom surface 3c to the lower surface 11a of the first plate portion 11, And the second opening portion 3e is opened from the bottom surface 3c to the lower surface 13a of the internal terminal portion 13. [

In the insert forming step of manufacturing the base body 3, the metal conductor 10 is provided inside the metal mold 20 partially shown in Figs. 5 and 6. 5, the first plate portion 11 is supported by the support protrusion 21 provided in the metal mold 20, and the internal terminal portion 13 is supported by the support protrusion 22 The molten resin is injected into the mold 20. The metal conductor 10 is supported by the support protrusions 21 and 22 to accurately position the metal conductor 10 in the cavity of the metal mold 20 and perform injection molding of the base body 3 .

When the molten resin injected into the mold 20 is cooled and solidified, the support protrusions 21 and 22 retract in the mold 20 and are extracted from the bottom wall 3a. So that the molded body 3 is taken out. The base 3 has a first opening 3d at a position where the support protrusion 21 is extracted and a second aperture 3e at a position where the support protrusion 22 is withdrawn.

5 has an inclined surface (tapered surface) formed around the distal end portion 21a that touches the metal conductor 10 so that no edge at a right angle is formed in the distal end portion have. Likewise, the distal end portion 22a of the support projection 22 shown in Fig. 5 is also formed with an inclined surface around it. The inclined surface around the distal ends 21a and 22a may be a convex curve when viewed in cross section or may be inclined in a straight line. By using the support protrusions 21 and 22, both the first openings 3d and the second openings 3e have the smallest cross-sectional area at the inner ends of the holes located on the insulating resin layer 31 side, Sectional shape becomes gradually larger toward the open end of the bottom surface 3c of the base body 3. [

As shown in Fig. 3, the metal conductor 10 has different surface treatment conditions depending on the place. The metal conductor 10 can be divided into sections (i), (ii), (iii) and (iv) according to the difference in the conditions.

3, the lower surface 11a of the first plate portion 11, the left surface 12a of the second plate portion 12, and the lower surface 13a of the internal terminal portion 13 are identical to each other in the section (i) Surface treatment is carried out.

Figs. 4, 5, and 6 are enlarged views of portions IV, V, and VI in Fig. As shown in these figures, in the section (i), the lower surface 11a of the first plate portion 11 and the left surface 12a of the second plate portion 12 and the lower surface 12a of the internal terminal portion 13 An insulating resin layer 31 is formed on the surface 13a and an adhesive resin layer 32 is formed on the insulating resin layer 31. [ 4 and 5, in the section (ii), the adhesive resin layer 32 is formed on the upper surface 11b of the first plate portion 11 and the right surface 12b of the second plate portion 12 .

It is necessary to increase the adhesion between the surfaces 11a, 12a and 13a of the metal conductor 10 and the insulating resin layer 31 in the section (i). In the section (ii) It is necessary to improve adhesion between the adhesive resin layer (11b, 12b) and the adhesive resin layer (32). Therefore, with respect to the surfaces 11a, 12a and 13a in the section (i) and the surfaces 11b and 12b in the section (ii), in the step before the resin layers 31 and 32 are formed An activation process is performed.

In the metal conductor 10 in the embodiment, silver plating is applied to both surfaces of the phosphor bronze plate, and various kinds of protective agents such as a fluorine-based anti-sulphide and rust preventive are applied to the surface of the silver plating. As the activation treatment, vacuum ultraviolet light is irradiated on the surface of the metal plate forming the metal conductor 10. As a light source of vacuum ultraviolet light, an excimer UV lamp (wavelength: 172 nm) in which xenon gas is enclosed is suitably used. Since the vacuum ultraviolet light has a large attenuation in the atmosphere, the distance between the metal conductor 10 and the lamp is reduced from several millimeters to several tens millimeters. When vacuum ultraviolet light is irradiated, the bond of the organic matter on the surface of the metal conductor 10 is cut by ultraviolet light having a low wavelength, and oxygen in the air between the lamp and the metal conductor 10 is decomposed to form ozone The protective agent on the surface is removed. At the same time, the polarity of the surface of the metal conductor 10 is promoted, so that the surface free energy is increased and the wettability is improved.

In the molding step of the insulating resin layer 31 and the adhesive resin layer 32, a resin material having affinity with each other is selected and used. After the insulating resin layer 31 is formed, the surface of the insulating resin layer 31 is irradiated with vacuum ultraviolet light to increase the surface free energy, and then the adhesive resin layer 32 is formed thereon. The adhesion between the layer 31 and the adhesive resin layer 32 can be enhanced.

The adhesive resin layer 32 has compatibility with the synthetic resin constituting the base body 3 and the synthetic resin constituting the adhesive resin layer 32 and the base body 3 is selected and used in the same system do. In the embodiment, the synthetic resin constituting the base 3 is polyamide-based, and so-called nylon 9T which is one type of engineer plastic is used. The adhesive resin layer 32 is formed using a two-liquid mixing type adhesive resin. In the resin for bonding in the embodiment, a nylon-based main agent is mixed with an isocyanate-based curing agent to form a polyamide, and a crosslinking reaction is caused by heat treatment.

Fig. 7 shows the relationship between the temperature rise and the state change of the nylon-based adhesive resin. The horizontal axis represents the heating temperature, the vertical axis represents the thermal change, the plus side of the vertical axis represents the exothermic reaction, and the minus side represents the endothermic reaction.

The range (a) in Fig. 7 is a process of drying the adhesive resin, and the adhesive resin is in a so-called hot melt state. When the solvent is heated to about 109 캜 and the solvent evaporates, it falls into the range of (b) to be in a dry state, and the crosslinking reaction starts with the temperature rise. When the temperature exceeds 150 占 폚 or 160 占 폚 and falls within the range of (c), the three-dimensional crosslinking is promoted and water becomes insoluble.

The adhesive resin layer 32 is applied to the surface of a metal plate constituting the metal conductor 10 by using an adhesive resin and is used in a state of being heated under the temperature condition in the range shown in Fig. 7 (b) . That is, a state in which the adhesive resin is dried under a heating condition of 110 ° C to 150 ° C or 110 ° C to 160 ° C, and is used in a partially cured state that is not completely cured. In the insert molding method, the adhesive resin layer 32 is heated and melted by contact with the molten resin injected into the mold, and the synthetic resin forming the adhesive resin layer 32 and the base 3 is in a commercial state. Therefore, the molded body 3 is fixed to the metal conductor 10.

As described above, the insulating resin layer 31 and the adhesive resin layer 32 are formed of a resin material having affinity with each other and good adhesion. In the embodiment, the insulating resin layer 31 is made of urethane resin, and isocyanate is used as a curing agent. It is known that the nylon resin and the urethane resin forming the adhesive resin layer 32 have a similar chemical structure and the same isocyanate-based curing agent is used for the insulating resin layer 31 and the adhesive resin layer 32. By selecting the resin as the insulating resin layer 31 and the adhesive resin layer 32, the adhesion between the resin layers is improved.

The insulating resin layer 31 is formed in a state in which it is not in the same hardened state as the adhesive resin layer 32 but is substantially insoluble since the three-dimensional crosslinking is promoted. That is, the adhesive resin layer 32 is formed in a state of hardened state with a low degree of crosslinking, but the insulating resin layer 31 is used in which the three-dimensional crosslinking is promoted more than the adhesive resin layer 32. Therefore, the insulating resin layer 31 is heated and used at a temperature higher than that of the adhesive resin layer 32. The heat treatment temperature of the insulating resin layer 31 is preferably 180 ° C or higher, for example. In the insert molding method, the adhesive resin layer 32 is in a state of compatibility with the synthetic resin constituting the base 3 as described above, but the insulating resin layer 31 is in a state of complete commercial use with the synthetic resin constituting the base 3 And is left on the surface of the metal conductor 10 as the insulating resin layer 31. [

Fig. 8 is an electron microscope photograph of a part of the cross-section of the substrate 3 on which the metal conductor 10 is inserted. The metal conductor 10 is formed by forming the insulating resin layer 31 after the surface is activated by vacuum ultraviolet light irradiation and activating the surface of the insulating resin layer 31 by irradiation with vacuum ultraviolet light to form the adhesive resin layer 32 ). This picture is 50,000 times. In Fig. 8, reference numeral 10 denotes a metal conductor and 10a denotes a plating layer. A structure is shown in which the insulating resin layer 31 is adhered to the surface of the plating layer 10a and the adhesive resin layer 32 is in a state of being in common use with the synthetic resin of the base body 3. [

The adhesive resin layer 32 formed on the two surfaces 11a and 11b of the first plate portion 11 of the metal conductor 10 in the base body 3 after the insert molding is bonded with the synthetic resin constituting the base body 3 And the adhesive resin layer 32 formed on the two surfaces 12a and 12b of the second plate portion 12 is in a commercial state with the synthetic resin constituting the base 3. [ This makes it difficult to form a gap in the contact portion between the metal conductor 10 and the bottom wall portion 3a of the base body 3 to increase the airtightness of the housing space 5 inside the housing 2 shown in Fig. . As a result, it is possible to reduce the possibility that the solvent, such as water or flux, or other liquid penetrates into the interior of the storage space 5 from the gap.

Since the adhesive resin layer 32 is also formed on both sides of the bending portion 15 at the boundary between the first plate portion 11 and the second plate portion 12 in the metal conductor 10, The synthetic resin constituting the metal conductor 10 and the base 3 can be firmly fixed.

In the insert molding method using the metal conductor 10 having the bent portion 15, the flow of the molten resin around the bent portion 15 is deteriorated. Therefore, when the resin is cooled and solidified, a deformation called a sink mark is likely to occur. If the bottom wall portion 3a is thin, the resin strength tends to decrease at the portion where the bent portion 15 is embedded. However, the adhesive resin layer 32 is provided on both sides of the first plate portion 11 and the second plate portion 12 located on both sides of the bent portion 15 and the adhesive resin layer 32 is also adhered to the surface of the bent portion 15. [ The metal conductor 10 and the base body 3 are firmly fixed to each other in the region including the bent portion 15 and the problem of the sink mark and the problem of the strength reduction are less likely to occur.

4, the adhesive resin layer 32 formed on the two surfaces 11a, 11b of the first plate portion 11 protrudes from the base body 3 at the portion where the external terminal portion 14 protrudes from the base body 3 3, so that the first plate portion 11 and the base body 3 are firmly fixed to each other. Therefore, no gap is formed between the metal conductor 10 and the base body 3 at the protruding base portion of the external terminal portion 14, and the airtightness of the storage space 5 can be maintained in a high state. It is also possible to increase the strength of the base body 3 around the protruding base portion of the external terminal portion 14.

The metal conductor 10 is cut off from the metal plate 10 having the insulating resin layer 31 and the adhesive resin layer 32 formed on the two surfaces thereof The insulating resin layer 31 and the adhesive resin layer 32 are formed on the upper surfaces 11a and 12a and the adhesive resin layer 32 is formed on the upper surfaces 11b and 12b. (The side where the plate thickness is shown), no resin layer is formed. Since the metal conductor 10 is heated in the insert molding step, the two surfaces 11a and 11b of the plate portion 11 and the two surfaces 12a and 12b of the plate portion 12 and the two surfaces 12a and 12b of the plate portion 12 The adhesive resin layer 32 formed on the surface 13a is heated and melted and part of the adhesive resin 32 that has been melted by the pressure of the molten resin during injection molding is pressed against the metal conductor 10 I go back to the side. Thereby, at least a part of the adhesive resin layer 32 is present between the side surface of the metal conductor 10 and the bottom wall portion 3a of the base body 3 and the side surface of the metal conductor 10 and the bottom wall portion 3a of the housing 2, and the airtightness of the housing space 5 inside the housing 2 can be enhanced.

3, the lower surface 13a of the internal terminal portion 13 is adhered to the synthetic resin constituting the base body 3 by the adhesive resin layer 32. In the section (iii) shown in Fig. On the other hand, as shown in Fig. 6, the upper surface 13b of the internal terminal portion 13 is exposed from the bottom wall 3a. The insulating resin layer 31 and the adhesive resin layer 32 are not formed on the upper surface 13b and the activation treatment using the vacuum ultraviolet light is not performed and the silver plating is performed under the protection of the anti- It is covered with zero.

The external terminal portion 14 is projected laterally of the base body 3 in the section iv but the insulating resin layer 31 and the adhesive layer 31 are also formed on the upper surface 14b and the lower surface 14a of the external terminal portion 14. [ The resin layer 32 is not formed and the activation treatment using vacuum ultraviolet light is not performed. Therefore, the surfaces 14a and 14b remain as they are covered with a protective agent such as an anti-sulphide agent.

The upper surface 13b of the internal terminal portion 13 and the lower surface 14a and the upper surface 14b of the external terminal portion 14 can be maintained in a state in which the silver plating is not easily corroded.

5 and 6, in the step of insert molding the base member 3, the lower surface 11a of the first plate member 11 abuts against the support projection 21 and is supported The mold and the support protrusions 21 and 22 are heated while the lower surface 13a of the internal terminal portion 13 is held in contact with the support protrusion 22. [ At this time, the adhesive resin layer 32 in the hardened state is melted at the portion where the support protrusions 21 and 22 abut and the adhesive resin layer 32 is peeled from the portion where the support protrusions 21 and 22 abut Removed. The adhesive resin layer 32 is heat-treated in the range of (b) in FIG. 7, and the adhesiveness is lowered compared with the hot-melt state in the range of (a). Therefore, the molten adhesive resin layer 32 hardly adheres to the distal end face or the like of the support protrusions 21, 22.

On the other hand, since the insulating resin layer 31 is formed in a three-dimensional cross-linked state, the surface of the metal conductor 10 is not insulated by the mold temperature even at the portion where the support protrusions 21, And is kept covered with the resin layer (31).

5 and 6, the insulating resin layer 31 is exposed inside the openings 3d and 3e, but the insulating layer 31 is widened outward beyond the openings 3d and 3e The insulating resin layer 31 is placed between the metal conductor 10 and the base 3 on the outer peripheral side of the openings 3d and 3e. Therefore, the surface of the metal conductor 10 exposed at the inner ends of the openings 3d and 3e can be insulated over the entire opening diameter. In addition, separation of the insulating resin layer 31 formed inside the openings 3d and 3e is also unlikely to occur.

The inclined surfaces are formed around the distal ends 21a and 22a of the support protrusions 21 and 22 so that the insulating resin layer 31 is formed at the tip of the support protrusions 21 and 22 It is hard to get damaged.

2 and 3, in the base body 3 after the insert molding, openings 3d and 3e passing from the bottom face 3c to the metal conductor 10 are formed in the bottom wall portion 3a of the base body 3, Are formed at a plurality of locations. 5 and 6, since the resin constituting the adhesive resin layer 32 and the base body 3 is cured after the resin is in a commercial state, the openings 3d and 3e The metal conductor 10 and the base 3 are closely adhered to each other. Therefore, no clearance is formed in the peripheral portion, and the airtightness in the storage space 5 can be further enhanced.

The metal conductors 10 are exposed inside the openings 3d and 3e opened on the bottom surface 3c of the bottom wall 3a. However, as shown in Figs. 5 and 6, the openings 3d and 3e, The surface of the metal conductor 10 is covered with the insulating resin layer 31 so that the insulation of the metal conductor 10 is maintained.

Since the housing 2 is a minute cube or a rectangular parallelepiped having a length of 5 mm or less and a length of 2 mm or less, liquid (including solvent such as flux) is attached to the bottom surface 3c of the base 3 , The liquid easily enters the openings 3d and 3e at a plurality of positions. However, since the surfaces of the metal conductors 10 shown at the bottoms of the openings 3d and 3e are covered with the insulating resin layer 31 and are insulated from each other, the metal conductors 10 are short- .

In the above embodiment, the nylon 9T is used as the synthetic resin constituting the base body 3, the nylon resin as the adhesive resin constituting the adhesive resin layer 32, and the resin constituting the insulating resin layer 31 as the urethane resin However, these resins are not limited to the above-mentioned combinations as long as they have mutual compatibility and affinity with each other. Based materials such as urethane-based, urethane-based, urethane-based, isocyanate-based, epoxy-based, isocyanate-based, urethane-based, Can be combined. The activation treatment for promoting the polarization is not limited to the irradiation of vacuum ultraviolet light, but may be plasma treatment, UV ozone treatment, corona treatment, chemical treatment, flame treatment, heat treatment, anodic oxidation treatment or the like.

1: Electronic component 2: Housing
3: gas 3a: bottom wall portion
3d, 3e: opening 5: storage space
6: Detecting element 10: metal conductor
11: first plate portion 11a: lower surface
11b: upper surface 12: second plate
12a: left surface 12b: right surface
13: internal terminal portion 13a: lower surface
13b: upper surface 14: external terminal portion
15: Bend 20: Mold
21, 22: support protruding body 31: insulating resin layer
32: Adhesive resin layer

Claims

An electronic component in which a metal conductor is embedded in a base made of a synthetic resin,
Wherein an opening is formed in the base to reach the surface of the metal conductor and a surface of the metal conductor exposed in the opening is covered with an insulating resin layer.

The method according to claim 1,
Wherein the base is insert-molded, and the opening is formed by a support protrusion for supporting the metal conductor in the metal mold.

The method according to claim 1,
Wherein the surface of the metal conductor on which the insulating resin layer is formed is activated.

3. The method of claim 2,
Wherein the surface of the metal conductor on which the insulating resin layer is formed is activated.

5. The method according to any one of claims 1 to 4,
Wherein the insulating resin layer is continuously formed from a portion exposed in the opening portion to a peripheral region covered with the base body.

5. The method according to any one of claims 1 to 4,
Wherein the opening has a portion gradually increasing in cross section from the inner end located on the insulating resin layer side toward the outside of the base.

6. The method of claim 5,
Wherein the opening has a portion gradually increasing in cross section from the inner end located on the insulating resin layer side toward the outside of the base.