JP3120793B2 - Method of manufacturing contact pins for printed circuit board inspection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a contact pin for inspecting a printed circuit board used in an inspection apparatus for electrically inspecting a wiring pattern or the like of a high-density printed circuit board. The present invention relates to a method of manufacturing a contact pin for inspection of a printed circuit board, which is compatible and has high conductivity and excellent flexibility.

[0002]

2. Description of the Related Art Generally, elements such as transistors, diodes, and resistors are incorporated in a printed circuit board at a high density in a predetermined wiring pattern. In an inspection device for electrically inspecting such a wiring pattern of a high-density printed circuit board, a contact pin for contacting an inspection location is used.

[0003] This type of contact pin for printed circuit board inspection is required to be electrically stably connected to inspection pads having different heights, and various techniques have been proposed.

For example, Japanese Patent Application Laid-Open No. 6-148237 discloses a cylindrical housing, a spring provided in the cylindrical housing, and a fitting provided in the cylindrical housing.
The movable pin includes a movable pin for breaking through the flux film by a spring pressure. The movable pin has a contact piece that comes into contact with the inspection location and a rotating body having a groove on the surface. There is disclosed a contact pin for printed wiring inspection having a projection for guiding a contact piece to rotate along a groove by a spring pressure when the contact is performed (hereinafter referred to as Conventional Example 1).

According to the contact pin of the prior art 1, the movable pin or the cylindrical housing is provided with a groove, and when the movable pin comes into contact with the inspection position, the movable pin is pushed down. The contact piece comes into contact with the inspection location while pushing away the flux film on the printed circuit board by this rotational force. Therefore, the movable pin and the inspection location surely come into contact with each other.

FIG. 7 is an explanatory view showing a printed circuit board inspection method (hereinafter referred to as Conventional Example 2) disclosed in JP-A-59-75162.

First, an elastic plate 51 having a large number of conductive paths 50 insulated from each other and arranged in a grid pattern is prepared (see FIG. 7A). The elastic plate 51 is made of rubber or the like, and the conductive path 50 of the elastic plate 51 is formed by, for example, a group of many metal particles.

Next, one surface of the elastic plate 51 is overlaid on one surface of the printed board 52, and
The receiving plate 54 is overlaid on the other surface of the device 2 via a buffer material layer 53 made of sponge or the like (see FIG. 7B).

Next, the tip of the contact pin 56 connected to the measuring instrument 55 is pressed against the portion of the elastic plate 51 located in the through hole 52a, which is the inspection location of the printed circuit board 52 (see FIG. 7C). ).

As a result, the tip of the contact pin 56 and the through hole 52a are connected to the conductive path 5 of the elastic plate 51.
Since it is electrically connected via the “0”, it is possible to inspect the inspection location.

[0011]

In the first prior art, since a spring must be provided in the cylindrical housing of the contact pin, the structure of the contact pin becomes complicated and the manufacturing cost increases. Further, it is technically difficult to manufacture minute contact pins, and there is a problem that electrical connection to minute test pads is not sufficient, and it is not possible to cope with inspection of a wiring pattern of a high-density printed circuit board.

In the conventional example 2, the elastic plate 51 having the conductive path 50 formed by a group of many metal particles is used.
Since the tip of the contact pin 56 is electrically connected to the inspection location, it is possible to electrically connect to minute pads, which provides a reasonable effect in high-density printed circuit board wiring pattern inspection.

However, in order to improve the electrical conductivity of the contact pins, Au must be plated on the surface of a metal sphere such as Cr in forming metal particles, so that fine metal particles must be formed uniformly. Difficult, 100μ
It is difficult to stably connect test pads of m □ or less.

Further, when the surface of the elastic plate 51 is physically damaged by the pressing of the contact pins 56 and the metal particles on the surface are lost, the connection resistance increases. There is a problem that the connection cannot be established.

An object of the present invention is to provide a method of manufacturing a contact pin for inspecting a printed circuit board, which can electrically stably connect to a minute inspection portion.

Another object of the present invention is to provide a method of manufacturing a contact pin which prevents damage to the contact pin due to contact with a test pad and improves the reliability of the test apparatus.

Still another object of the present invention is to provide a method of manufacturing contact pins which prevents a manufacturing defect due to a displacement between an electrode pad and a contact pin and improves the yield and productivity of an inspection device.

[0018]

According to the present invention, there is provided a method of manufacturing a contact pin for inspecting a printed circuit board, comprising the steps of providing a substrate having an electrode pad on one surface, and providing a thickness from the electrode pad to the other surface of the substrate. A step of forming a through hole penetrating in the direction, a step of forming a photosensitive resin layer on one surface of the substrate, and irradiating the photosensitive resin layer with light through the through hole from the other surface of the substrate, A step of forming a photopolymerized portion on the electrode pad of the substrate, and forming the photopolymerized portion on a conductive polymer molded body, and immersing the photopolymerized portion in a reaction solution for removing a photosensitive resin layer other than the photopolymerized portion, It is characterized by having.

The through hole is preferably formed at a position substantially at the center of the electrode pad and inside the electrode pad.

The photosensitive resin layer mainly comprises, for example, an acrylic compound or a polymer of an acrylic compound.

The conductive polymer is, for example, polypyrrole,
Polyaniline or polyethylene dioxythiophene.

It is preferable to adjust the energy of the irradiated light so that the photosensitive resin layer is not completely photopolymerized in the thickness direction.

The side surface of the formed through hole may be covered with a metal body electrically connected to the electrode pad.

The side surface of the through hole may be covered with a metal body, and the metal body may be electrically connected to the electrode pad.

The photosensitive resin layer may be embedded in the through hole.

According to the present invention, since a photochemical reaction is used, fine contact pins can be formed.

The contact pin can be formed in a truncated cone shape by adjusting the energy of the irradiation light so that the photosensitive resin layer is not completely photopolymerized in the thickness direction.

Further, since the light is radiated through the through-holes, by forming the through-holes at a position substantially at the center of the electrode pad, it is possible to prevent a manufacturing defect due to a positional shift between the electrode pad and the contact pin. .

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a printed circuit board inspection apparatus provided with a printed circuit board inspection contact pin manufactured by the manufacturing method of the present invention.

As shown in FIG. 1, the printed board inspection apparatus includes a glass epoxy board 11, a wiring 13 provided on the glass epoxy board 11, and an electrode pad 12 electrically connected to the wiring 13. , Its electrode pads 12
And a contact pin 14 provided thereon.

The electrode pad 12 is made of a metal such as Cu. The contact pin 14 is made of, for example, a molded body of a conductive polymer such as polypyrrole, polyaniline, or polyethylenedioxythiophene, and is formed in a substantially truncated cone shape.
Then, the wiring pattern is inspected by pressing the contact pins 14 so as to be electrically connected to the inspection pads or the like of the printed circuit board to be inspected.

2 and 3 are sectional views showing a method of manufacturing a contact pin for printed circuit board inspection according to the first embodiment of the present invention in the order of steps.

First, the electrode pad 12 formed on the surface of the glass epoxy substrate 11
A through hole 21 penetrating in the thickness direction up to the back surface of the substrate 1 is formed. The through hole 21 is formed substantially at the center of the electrode pad 12 and inside the electrode pad 12 (see FIG. 2A).

Next, a photosensitive resin layer 31 is applied on the surface of the glass epoxy substrate 11 on which the electrode pads 12 are provided (see FIG. 2B). The photosensitive resin layer 31 mainly includes, for example, an acrylic compound or a polymer of an acrylic compound.

Next, the back surface of the glass epoxy substrate 11 on which the electrode pads 12 are not provided is irradiated with ultraviolet light 32 (see FIG. 3A). As a result, the electrode pad 12 irradiated with the ultraviolet light 32 passing through the through hole 21
The upper photosensitive resin layer 31 forms a photopolymerized portion by a photochemical reaction.

Thereafter, it is immersed in a reaction solution 33 capable of forming a conductive polymer molded body 34 (see FIG. 3B). Thereby, the conductive polymer molded body 34 is formed in the photopolymerized portion,
In addition, the photosensitive resin layer 31 other than the photopolymerized portion is removed.

Through the above steps, as shown in FIG. 3C, the contact pins 14 made of the conductive polymer molded body are formed only on the electrode pads 12.

The contact pin 14 has a truncated cone shape. The reason will be described with reference to FIG. The energy of the ultraviolet light 32 to be applied is adjusted so that the photosensitive resin layer 31 is not completely photopolymerized in the thickness direction. Therefore, as shown in FIG. 4A, the photosensitive resin layer 31 in the vicinity of the through hole 21 can be sufficiently photopolymerized, but the irradiation intensity of the ultraviolet light 32 decreases along the thickness direction. The ultraviolet light 32 reaches the surface of the resin layer 31 at the central portion of the photosensitive resin layer 31, but is reflected and scattered at other portions. Therefore, due to the reflected scattered light, a light-cured portion is also formed outside the through-hole 21, and the light-cured region near the electrode pad 12 has a diameter larger than the diameter of the through-hole 21. As a result, FIG.
As shown in (B), the shape of the contact pin 14 is a truncated cone with the electrode pad 12 as the bottom surface.

According to the present invention, since the photochemical reaction is used, fine contact pins 14 can be formed. Therefore, it is possible to inspect a high-density printed circuit board having minute inspection pads.

Further, since the contact pin 14 has a truncated cone shape, it is possible to prevent the contact pin 14 from being broken by pressure when the contact pin 14 is brought into contact with the inspection pad. As a result, the reliability of the inspection device can be improved.

Further, since the photosensitive resin layer 31 is irradiated with the ultraviolet light 32 through the through hole 21 located substantially at the center of the electrode pad 12, a manufacturing defect due to a displacement between the electrode pad 12 and the contact pin 14 is prevented. be able to. As a result, the yield and productivity of the inspection device can be improved.

Next, a second embodiment of the present invention will be described with reference to the drawings. 5 and 6 are sectional views showing a method of manufacturing a contact pin for printed circuit board inspection according to the second embodiment of the present invention in the order of steps.

First, the substrate 1 is placed on the glass epoxy substrate 11 at a position substantially at the center of the electrode pad 12.
A through hole 21 is formed to penetrate to the back surface of No. 1. The through hole 21 is formed inside the electrode pad 12.
Further, since the metal body 41 covers the side surface of the through hole 21, the contact resistance is reduced. The electrode pad 12 and the metal body 41 are electrically connected (see FIG. 5).
(A)).

Next, a photosensitive resin layer 31 is applied on the surface of the glass epoxy substrate 11 on which the electrode pads 12 are provided, and the photosensitive resin layer 3 is also provided in the through holes 21.
1 is embedded (see FIG. 5B).

Next, the back surface of the glass epoxy substrate 11 on which the electrode pads 12 are not provided is irradiated with ultraviolet light 32 (see FIG. 6A). As a result, the photosensitive resin layer 31 embedded in the through hole 21 and the photosensitive resin layer 31 on the electrode pad 21 form a photopolymerized portion by a photochemical reaction caused by irradiation of the ultraviolet light 32.

Thereafter, it is immersed in a reaction solution 33 capable of forming a conductive polymer molded body 34 (see FIG. 6B). As a result, the conductive polymer molded body 34 is formed in the photopolymerized portion, the photosensitive resin layer 31 other than the photopolymerized portion is removed, and the conductive polymer molded body is formed only in the through hole 21 and on the electrode pad 12. 34 are formed.

Through the above steps, a contact pin 14 having the shape shown in FIG. 6C is obtained. Contact pin 14
Have a shape embedded in the through hole 21.

According to the second embodiment, since the contact pins 14 partially buried in the through holes 21 are obtained, it is possible to further prevent the contact pins 14 from being broken by pressure. The present invention is not limited to the above embodiments, and various changes can be made within the scope of the technical matters described in the claims.

[0049]

Embodiments of the present invention will be described below. FIG.
1 shows a printed board inspection apparatus provided with a contact pin for inspecting a wiring pattern of a printed board manufactured by the manufacturing method of the present invention.

As shown in FIG. 1, a printed board inspection apparatus comprises a glass epoxy board 11 and a glass epoxy board 1.
1, an electrode pad 1 made of Cu and arranged at the size and position of an inspection pad on a printed circuit board to be inspected.
2 and wiring 13 electrically connected to electrode pad 12
And a contact pin 14 provided on the electrode pad 12
And Then, the contact pins 14 are pressed against the inspection pads of the printed circuit board to be electrically connected, and the wiring pattern is inspected. Next, an example of the first embodiment of the present invention will be described in detail with reference to the drawings.

First, the substrate 1 is moved from the electrode pad 12 to a position substantially at the center of the electrode pad 12 on the glass epoxy substrate 11.
A through hole 21 penetrating in the thickness direction up to the back surface of the substrate 1 is formed. The through hole 21 is smaller than the size of the electrode pad 12, for example, when the size of the electrode pad 12 is 60 μm.
In the case of m □, it is formed in a circular shape having a diameter of about 40 μm.

The through holes 21 are formed by laser processing or the like generally used in the manufacture of the printed circuit board 11. The surface of the electrode pad 12 is preferably plated with Au. In addition, through hole 2
The shape of 1 is not limited to a circle, but may be a polygon.

Next, a urethane acrylate photosensitive solution containing 50% by weight of an ethanol solution (concentration: 20 to 30% by weight) in which ferric dodecylbenzenesulfonate is dissolved is provided on the surface of the glass epoxy substrate 11 provided with the electrode pads 12. Resin layer 31 (KAYARAD UX manufactured by Nippon Kayaku Co., Ltd.)
-3204, hexamethylene diisocyanate, Alonix M-5700 manufactured by Toa Gosei Co., Ltd.) were heated and dropped at 60 ° C., a resin layer of about 100 μm was formed using a bar coater, and dried under reduced pressure at room temperature for 24 hours (FIG. 2
(B)).

Next, the ultraviolet light 32 is applied to the back surface of the glass epoxy substrate 11 on which the electrode pads 12 are not provided.
Irradiation is performed at an irradiation intensity of 0 mW / cm 2 for 60 minutes to form a corrosion-resistant image (see FIG. 3A). Here, the corrosion-resistant image refers to a portion in which a portion irradiated with light (photopolymerized portion) and a portion not irradiated with light are combined.

The ultraviolet light 32 passes through the through hole 21 and irradiates only the photosensitive resin layer 31 on the electrode pad 12. At that time, the ultraviolet light 32 is partially reflected by ferric dodecylbenzenesulfonate. When the absorption coefficient of the ultraviolet light 32 was measured, it was 2.4E3 at a light wavelength of 360 nm. The thickness at which the resin layer 31 can be sufficiently photopolymerized is about 50 μm, and the irradiation intensity of the ultraviolet light 32 in the remaining 50 μm decreases in the thickness direction. In addition, through-holes 2 are formed in the photopolymerized region near the electrode pad 12 due to the reflected scattered light.
1 (see FIGS. 4A and 4B). As a result, the shape of the corrosion-resistant image is a truncated cone with the electrode pad 12 as the bottom surface.

Thereafter, the substrate 11 is immersed in a reaction solution 33 which is butyl alcohol or isopropyl alcohol containing 5% by weight of pyrrole, and is kept at room temperature for 15 to 30 minutes to simultaneously develop a corrosion-resistant image and polymerize polypyrrole. A urethane acrylate-based conductive polymer molded body 34 on which conductive polypyrrole was formed was obtained (see FIG. 3B). The molded body 34 was a truncated cone having a bottom surface diameter of 60 μm, an upper surface diameter of 30 μm, and a height of 100 μm, and had a shape suitable for a contact pin for inspecting a printed wiring board.
Through the above steps, as shown in FIG. 3C, the shape of the contact pin 14 was a circular truncated cone having a bottom surface of 60 μm in diameter and a top surface of 30 μm in diameter. Since the obtained contact pin 14 can be elastically deformed up to 20% of its height, it can be brought into close contact with wiring pads of different heights. Further, since the electric resistance is 5Ω, not only the open / short inspection of the printed wiring board 11 but also the operation test can be performed.

As a result, the strength of the contact pin 14 against the pressure applied when the contact pin 14 is brought into contact with the test pad is improved as compared with the cylindrical shape, and the contact pin 14 can be brought into contact with a small test pad having a size of 30 μm square. Becomes

Since the resin layer 31 is irradiated with the ultraviolet light 32 through the through hole 21 located at the center of the electrode pad 12, a photomask used for patterning by the conventional photochemical reaction is not required, and the electrode pad 12 and the The effect of preventing a manufacturing defect due to a displacement of the contact pin 14 is obtained. Next, an example of the second embodiment of the present invention will be described in detail with reference to the drawings.
First, as shown in FIG.
At a position substantially at the center of the electrode pad 12 formed on the surface of the substrate 1, a through hole 21 is formed that penetrates from the electrode pad 12 to the back surface of the substrate 11 in the thickness direction. Through hole 2
1 is smaller than the size of the electrode pad 12. For example, when the size of the electrode pad 12 is 60 μm
It is formed in a circular shape of about μm.

The side surface of the through hole 21 is covered with a metal body 41 such as Cu or Au with a thickness of about 3 to 5 μm. The electrode pad 12 and the metal body 41 are electrically connected. The shape of the through hole 21 is not limited to a circle, but may be a polygon.

Next, a urethane acrylate photosensitive solution containing 50% by weight of an ethanol solution (concentration: 20 to 30% by weight) in which ferric dodecylbenzenesulfonate is dissolved is formed on the surface of the glass epoxy substrate 11 provided with the electrode pads 12. Resin layer 31 (KAYARAD UX manufactured by Nippon Kayaku Co., Ltd.)
-3204, hexamethylene diisocyanate, Aronix M-5700 manufactured by Toagosei Co., Ltd.) are heated and dropped at 60 ° C., and a resin layer 31 of about 100 μm is formed using a bar coater. At this time, since the resin layer 31 is embedded in the through hole 21, it is preferable to form the through hole 21 in a vacuum.

Thereafter, drying was performed under reduced pressure at room temperature for 24 hours. Thereafter, as in the example of the first embodiment, the back surface of the glass epoxy substrate 11 on which the electrode pads 12 are not provided is irradiated with ultraviolet light 32 at an irradiation intensity of 60 mW / cm 2 for 60 minutes to obtain a corrosion-resistant image. Was formed. Since the resin layer 31 in the through-hole 21 and the resin layer 31 on the electrode pad 12 passing through the through-hole 21 are also irradiated with the light 32, the intensity of the ultraviolet light 32 is less than that of the example of the first embodiment. I made it higher. At this time, the ultraviolet light 32 is partially reflected by ferric dodecylbenzenesulfonate. When the absorption coefficient of the ultraviolet light 32 was measured, it was 2.4E3 at a light wavelength of 360 nm. Although the resin layer 31 in the through hole 21 is completely photopolymerized, the resin layer 31 on the electrode pad 12 is sufficiently photopolymerized to have a thickness of about 50 μm, and the remaining 50 μm corresponds to the ultraviolet light 32 in the thickness direction. Irradiation intensity decreases.
The diameter of the through-hole 21 is larger than the diameter of the through hole 21 in the photopolymerization region near the electrode pad 12 due to the reflected scattered light. As a result, the shape of the corrosion resistance image was a truncated cone with the electrode pad 12 as the bottom surface.

Thereafter, the substrate 11 is immersed in a reaction solution of butyl alcohol or isopropyl alcohol containing 5% by weight of pyrrole, and kept at room temperature for 15 to 30 minutes to simultaneously develop the corrosion-resistant image and polymerize the polypyrrole, A urethane acrylate-based conductive polymer molded article on which a conductive polypyrrole was formed was obtained. This molded body was a truncated cone having a diameter of 60 μm on the bottom surface, a diameter of 30 μm on the top surface, and a height of 100 μm, and had a shape suitable for the contact pins 14 for inspecting a printed wiring board. Through the above steps, FIG.
The contact pin 14 having the shape shown in FIG. The shape of the contact pin 14 is a circular truncated cone having a bottom surface having a diameter of 60 μm and an upper surface portion having a diameter of 30 μm, and a part of the bottom surface portion is embedded in the through hole 21. Since the obtained contact pin 14 can be elastically deformed up to 20% of its height, it can be brought into close contact with wiring pads of different heights. Further, since the electric resistance is 5Ω, not only the open / short inspection of the printed wiring board 11 but also the operation test can be performed. As compared with the example of the first embodiment, a part of the contact pin 14 is buried in the through hole 21, so that the contact pin 14 can be more prevented from being broken by pressure. The present invention
The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the technical matters described in the claims.

[0063]

According to the present invention, since a photochemical reaction is used, fine contact pins can be formed. Therefore, it is possible to inspect a high-density printed circuit board having minute inspection pads. In addition, by adjusting the energy of the irradiated light so that the photosensitive resin layer is not completely photopolymerized in the thickness direction, the contact pin can be formed in a truncated cone shape. It is possible to prevent the contact pin from being broken due to the pressurization at the time of contact. As a result, the reliability of the inspection device can be improved.

Further, since the light is radiated through the through-hole, by forming the through-hole substantially at the center of the electrode pad, it is possible to prevent a manufacturing defect due to a positional shift between the electrode pad and the contact pin. . As a result, the yield and productivity of the inspection device can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a printed circuit board inspection apparatus provided with a printed circuit board inspection contact pin manufactured by the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view illustrating a method for manufacturing a contact pin for printed circuit board inspection according to the first embodiment of the present invention in the order of steps.

FIG. 3 is a cross-sectional view illustrating a method of manufacturing a printed circuit board inspection contact pin according to the first embodiment of the present invention in the order of steps.

FIG. 4 is an explanatory diagram for explaining the reason why the contact pin has a truncated cone shape.

FIG. 5 is a sectional view illustrating a method of manufacturing a contact pin for printed circuit board inspection according to a second embodiment of the present invention in the order of steps.

FIG. 6 is a sectional view illustrating a method of manufacturing a contact pin for printed circuit board inspection according to a second embodiment of the present invention in the order of steps.

7A is a plan view of an elastic plate used in a conventional printed circuit board inspection method, and FIGS. 7B and 7C are cross-sectional views illustrating a conventional printed circuit board inspection method.

[Explanation of symbols]

 11: Glass epoxy substrate 12: Electrode pad 13: Wiring 14: Contact pin 21: Through hole 31: Photosensitive resin layer 32: Ultraviolet light 33: Reaction solution 34: Conductive polymer molded body 41: Metal body

Continuation of the front page (72) Inventor Yosuke Itagaki 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (56) References JP-A-11-326380 (JP, A) (58) Fields surveyed ( Int.Cl. ⁷ , DB name) G01R 1/06-1/073 G01R 31/26 H01L 21/66

Claims (7)

(57) [Claims] A step of preparing a substrate having an electrode pad on one surface; a step of forming a through hole extending in a thickness direction from the electrode pad to the other surface of the substrate; Forming a photosensitive resin layer on a surface; and irradiating the photosensitive resin layer with light from the other surface of the substrate via the through hole to form a photopolymerized portion on the electrode pad of the substrate. A printed circuit board comprising: a step of forming the photopolymerized portion on a conductive polymer molded body, and immersing the photopolymerized portion in a reaction solution for removing the photosensitive resin layer other than the photopolymerized portion. Manufacturing method of contact pins for inspection. 2. The method according to claim 1, wherein the through hole is formed at a position substantially at the center of the electrode pad and inside the electrode pad. 3. The method according to claim 1, wherein the photosensitive resin layer mainly comprises an acrylic compound or a polymer of an acrylic compound. 4. The method according to claim 1, wherein the conductive polymer is a substance selected from the group consisting of polypyrrole, polyaniline, and polyethylenedioxythiophene.
4. The method for manufacturing a contact pin for printed circuit board inspection according to any one of Items 3 to 3. 5. The energy of the irradiating light is adjusted so that the photosensitive resin layer is not completely photopolymerized in the thickness direction. A method for manufacturing a contact pin for printed circuit board inspection according to one item. 6. The printed circuit board inspection according to claim 1, wherein a side surface of the formed through hole is covered with a metal body electrically connected to the electrode pad. Of manufacturing contact pins for semiconductors. 7. The method according to claim 1, wherein the photosensitive resin layer is embedded in the through hole.