JPH1164384A - Manufacture of probe head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily cope with the increase of the number of conductive pads on a printed circuit board and the reduction of the pitch of the pad and to reduce a manufacturing cost. SOLUTION: A through hole is formed at an insulated substrate 10 coated with copper foils 11 and 12 and uncured conductive resin is packed inside the through hole and cured to form a probe terminal 13. Next, the foils 11 and 12 are removed by etching to make the state of projecting the tip of the terminal 13 by the thickness portion of the copper foils.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a probe head, and more particularly to a manufacturing technique suitable for a probe head used in a board inspection apparatus for performing a circuit inspection of a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, in a board inspection apparatus for inspecting a circuit pattern of a printed circuit board, a probe head having a large number of probe pins planted thereon is brought into contact with the printed circuit board to short circuit the circuit and cut the wiring. It is configured to check other electrical states. In this case, the probe pin is generally configured so as to be able to protrude and retract in a state in which a conductive terminal portion provided at the distal end is urged in a protruding direction with respect to the pin body by a spring or the like.

[0003] In the probe head, a large number of mounting holes are formed by drilling or the like on the insulating substrate at positions corresponding to the positions of the conductive pads provided on the circuit pattern of the printed circuit board to be inspected. After the probe pins are implanted, a wiring for connecting to an electric measuring instrument is formed at the base of the probe pins by conductive connection.

[0004]

However, in a probe head having a large number of probe pins implanted therein, it is necessary to provide a terminal portion for each probe pin and a spring structure for biasing the terminal portion. In addition, since a large number of probe pins need to be implanted on the insulating substrate, there is a problem that the production is troublesome and expensive.

In recent years, the number of conductive pads on a printed circuit board has been increased and the pitch has been reduced in accordance with the reduction in the terminal spacing of ICs and LSIs. Since the number of the probe heads is increased, the spacing between the implants is reduced, and the outer diameter of the probe pins themselves must be reduced, the manufacturing cost of the probe head is further increasing. It's getting harder.

SUMMARY OF THE INVENTION Accordingly, the present invention is to solve the above-mentioned problems, and an object of the present invention is to make it possible to easily cope with an increase in the number of conductive pads on a printed circuit board and to reduce the pitch, and to reduce the manufacturing cost. It is an object of the present invention to provide a novel method of manufacturing a probe head which can reduce the number of probe heads.

[0007]

Means taken by the present invention to solve the above-mentioned problem is to provide a composite substrate having a coating layer on the surface of an insulating substrate through a through-hole penetrating through the coating layer. Forming a probe terminal made of a conductive resin, and a step of removing the coating layer. This is a method for manufacturing a probe head.

According to this means, a through hole is formed in a composite base material provided with a coating layer on the surface of an insulating base, and a conductive resin is filled and cured to form a probe terminal. As a result, the probe terminals protruding from the surface of the insulating base by the thickness of the coating layer can be formed. However, it can be easily handled and can be manufactured at low cost.

When the above-mentioned coating layer is formed on the back surface as well as on the front surface of the insulating base, and after forming the probe terminals, both the front and back coating layers are removed. The probe terminals can be easily electrically conductively connected to the terminals of the inspection apparatus. For example, conduction can be achieved by pressing the probe head against a press plate of the inspection apparatus.

Here, in the step of forming the through-hole, it is preferable that the inner surface of the through-hole is made uneven or roughened so as to be an engagement surface for engaging with the probe terminal.

According to this means, since the inner surface of the through hole is made uneven or roughened, it is possible to prevent the probe terminal formed inside the through hole from falling off or being displaced. Yield and durability can be improved.

It is preferable that the insulating base is made of a synthetic resin containing fibers, and a part of the fibers protrudes from the insulating base to an inner surface of the through hole.

According to this means, the insulating resin is composed of synthetic resin containing fibers, and the fibers are protruded from the inner surface of the through-hole, whereby the conductive resin is filled into the through-hole and cured. As a result, the probe terminal is strongly fixed to the insulating base, so that the probe terminal can be prevented from dropping or displacing.

In this case, it is particularly desirable that the insulating base is made of a synthetic resin containing fibers in a woven state.

According to this means, since the insulating base is made of a synthetic resin containing fibers in a woven state, the fixing force between the probe terminal in the through hole and the insulating base can be further increased.

Further, the conductive resin is preferably a synthetic rubber containing conductive particles.

According to this means, by forming the conductive resin with the synthetic rubber containing the conductive particles, it is possible to impart elasticity to the probe terminals, thereby improving the conductivity and the tolerance to the shape of the inspection object. In addition, by using synthetic rubber containing conductive particles, the elastic characteristics and conduction characteristics of the probe terminals can be appropriately set.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method for manufacturing a probe head according to the present invention will be described with reference to the accompanying drawings. This embodiment relates to a probe head used for a board inspection apparatus for a printed wiring board. However, the present invention is not limited to such an application, and various probes that can be used for various electrical tests and the like are provided. It can be applied to the head.

In this embodiment, as shown in FIG. 1A, a commercially available copper foil base material having copper foils 11 and 12 adhered to the front and back surfaces of an insulating substrate 10 made of glass epoxy resin is used. Using. The insulating substrate 10 is obtained by impregnating and laminating a woven cloth made of glass fiber with an epoxy resin and curing the impregnated cloth.

Next, as shown in FIG. 1B, a large number of through holes 10a are formed by drilling an insulating substrate 10 through copper foils 11 and 12 using a drill or the like. The through hole 10a is
The drilling machine is controlled by a programmable controller or the like in which the positions of the conductive pads of the printed circuit board to be inspected are stored in advance, and drilling is performed continuously. Through hole 1
The formation of Oa can be performed by a laser processing machine.

Next, as shown in FIG. 1C, a probe terminal 13 is formed by filling the inside of the through hole 10a with an uncured conductive resin and curing the resin. As the conductive resin, a resin obtained by mixing conductive particles with synthetic rubber is preferable. However, a resin having sufficient elasticity or flexibility after curing may be used without being a synthetic rubber. Resins and the like can also be used. The curing properties of these conductive resins are, in addition to curing by drying,
Thermal curing or light curing may be used.

Thereafter, the copper foils 11 and 12 on the front and back surfaces of the insulating substrate 10 are removed with an alkaline etching solution, and as shown in FIG. The probe head is formed by making the state where 13 protrude by the thickness of the copper foils 11 and 12.

Here, in the step of forming the through hole 10a shown in FIG. 1B, it is particularly important that the inner surface of the through hole 10a is made uneven or roughened. If the inner surface of the through-hole 10a is roughened or roughened, the probe terminal 13 is firmly fixed to the inner surface of the through-hole 10a by being filled with uncured conductive rubber and then cured. Even if the probe terminal 13 is repeatedly pressed against the circuit board and repeatedly applies stress, the probe terminal 13 is prevented from dropping from the insulating substrate 10 and the protrusion dimension of the probe terminal 13 is not changed due to displacement. Is suppressed.

The roughening and roughening of the inner surface of the through hole 10a
It is preferably formed naturally by drilling or the like. In the present embodiment, since a glass fiber woven fabric immersed in a synthetic resin and laminated is used as the insulating substrate 10, a large number of glass fibers are projected on the inner surface of the through hole 10 a by drilling, and especially the consciousness is increased. It is possible to enhance the adhesion between the insulating substrate 10 and the probe terminals 13 without performing any special processing. As such a fiber-containing resin, silicone resin, phenolic resin and the like are filled with glass fiber, carbon fiber, paper fiber, and the like,
Mixtures and the like can also be used.

The roughening and roughening of the inner surface of the through hole 10a
It is also possible to consciously perform the drilling. For example, by forming a spiral groove or a circumferential groove on the inner surface of the through hole 10a by drilling, the adhesion between the insulating substrate 10 and the probe terminals 13 can be enhanced. Further, even if the inner surface of the through-hole is not intentionally provided with irregularities such as grooves and ribs, the inner surface of the through-hole can obtain the fixing force of the probe terminal 13 depending on the material of the insulating substrate and the processing method such as drilling. It is possible to form a sufficiently rough surface.

Examples of the conductive resin include solid conductive particles such as Ni particles, carbon particles, and Au particles, and conductive particles having a conductive property on at least the surface portion such as resin particles having a gold-plated surface. Can be used. The diameter of the conductive particles can be appropriately adjusted according to conditions such as the diameter and pitch of the probe terminals.
Usually, it is appropriately set depending on the thickness, outer diameter, protrusion amount, and the like of the probe terminal, but is generally in the range of several μm to several hundred μm. In the case of Ni particles, sufficient conductivity as a conductive resin can be obtained by mixing 25% by weight or more.

In the step of filling the conductive resin, FIG.
As shown in (a), first, a conductive resin 15 is applied on the front and back surfaces of the copper foil base material, respectively, and the conductive resin 15 applied on the front surfaces of the copper foils 11 and 12 is penetrated by a squeegee 16. While pushing the copper foils 11 and 12 into the holes 10a,
The conductive resin remaining on the surface of the substrate is scraped off. This filling operation is performed on each of the front surface and the back surface of the copper foil substrate, and preferably, the squeegee 16 is run on the front surface and the back surface twice or more.

Next, the copper foil base material filled with the conductive resin 15 is accommodated in a chamber, and the inside of the chamber is decompressed.
Perform defoaming treatment. The viscosity of the conductive resin 15 is adjusted in advance so that air bubbles remaining inside by the defoaming treatment are sufficiently removed. Fig. 2
As shown in (b), the release surface of the copper foil base material (in the illustrated state, the back surface of the copper foil base material is in contact with a support base or the like, and the surface of the copper foil base material is released into the chamber. ), Bubbles inside the conductive resin 15 are released, and the surface thereof rises slightly.

Further, the copper foil substrate subjected to the defoaming treatment is taken out of the chamber, and as shown in FIG. While pressing in, the surface is made to match the surface of the copper foil 11.

In the step of filling the conductive resin, if the conductive resin adheres to the surface of the copper foil, a film residue may be generated in the etching of the copper foil. It is desirable to cut or polish the surface of the foil, or to sharpen the tip of the squeegee 16 to prevent the conductive resin from adhering.

Finally, when the conductive resin 15 is a thermosetting resin, as shown in FIG. 2D, a copper foil base material is sandwiched between the heating plates 17 with built-in heaters. And press blocks 18, 19 from above and below the heating plate 17.
To cure the thermosetting resin 15 to form the probe terminals 13. Here, press block 1
By performing thermosetting while applying a magnetic field in a direction perpendicular to the surface of the insulating substrate 10 while applying pressure by 8 and 19, the conductivity of the probe terminals 13 in the vertical direction can be increased.

As a result of actually manufacturing the probe head according to the above-described embodiment, it was possible to form a probe head that can cope with a printed circuit board (substrate to be inspected, described later) having a much finer pitch than before.

FIG. 3 is a cross-sectional view of FIG. 1 formed as described above.
FIG. 9D shows a method of inspecting the probe head shown in FIG. A conductive plate 20 is brought into contact with one surface of a probe head including an insulating substrate 10 and a probe terminal 13, and a test substrate 21 having a plurality of conductive pads 21 a at a position where the probe terminal 13 is formed is brought into contact with the other surface. As a result, the protruding ends of the probe terminals 13 are
And the conductive pad 21a.

The test board 21 has individual conductive pads 2
A wiring pattern (not shown) constituting the lead wiring connected to 1a is formed, and through this wiring pattern,
The probe terminal 13 is electrically connected to a test device (not shown).

In the state shown in the drawing, it is possible to know which of the probe terminals 13 has a conduction failure by checking whether or not there is conduction between the probe terminals 13. Further, when the conductive plate 20 is separated from the probe terminals 13 and the conduction between the probe terminals 13 is checked again, the presence or absence of a short circuit between the probe terminals 13 can be known.

FIG. 4 is a schematic sectional view showing a situation in which the above-described probe head is mounted on a substrate inspection apparatus and used. Here, a plurality of guide holes 10b are formed in the periphery of the probe head shown in FIG. On the back side of the probe head, a press plate 22 attached to the substrate inspection device is arranged so as to be able to move up and down. This press plate 2
A tapered guide shaft 22b is attached and fixed to a peripheral portion of the guide member 2 at a position corresponding to the guide hole 10b. A conductive terminal 22a is embedded in the press plate 22 at a position corresponding to the position where the probe terminal 13 is formed, and a test wiring 22 is provided on the back side of the conductive terminal 22a.
c is conductively connected.

A predetermined circuit pattern (not shown) is formed on the surface of the substrate 23 to be inspected.
Many conductive pads 23a are provided. When inspecting the substrate 23 to be inspected, the press plate 22 is moved to fit the guide shaft 22b into the guide hole 10b of the probe head, and the press plate 22 and the probe head are integrated with the substrate 23 to be inspected. Pressed. The probe terminals 13 of the probe head contact the corresponding conductive pads 23a, and are conductively connected to the conductive terminals 22a via the probe terminals 13.

In this embodiment, the press plate 22 has a structure in which the conductive terminals 22c are buried. However, the press plate 22 is formed of a wiring pattern formed on the surface or the like as in the test substrate 21 of FIG. May be constituted by printed wiring boards provided with conductive pads respectively connected to the printed circuit boards. However, when such a printed wiring board is a single-layer board, since the wiring pattern must be routed in the plane of the board, there is a limit in increasing the formation density of the conductive pads and reducing the formation pitch. is there. Therefore, it is desirable to use a laminated substrate having a plurality of pattern layers in the substrate.

In any case, the probe head of this embodiment is configured to be used by positioning it on an electrode member (conductive mediating member) having an electrode having no spring property, such as a rigid pin head. Things.

Various fibers can be contained in the insulating substrate as described above. In particular, high strength and high elasticity such as glass fiber, carbon fiber, aramid fiber, silicone fiber, silicon carbide fiber, and boron fiber are used. What contains the reinforcing fiber of the above is preferable. These fibers may be included in the insulating resin in a mixed and dispersed state, but are included in various woven states such as a plain woven cloth, a satin woven cloth, a roving cloth, and a filament winding. Is preferred. Also,
It is more preferable to form by laminating resin layers in which these fibers are woven.

The coating layer is preferably made of a material that can be easily removed by a method such as etching since it will be removed later. The coating layer may be an insulator or a conductor. When the covering layer is made of a conductor, the test can be performed using the conductive plate 20 shown in FIG.

As the conductive resin, a resin having elasticity as a probe terminal after curing is preferable. As described above, it is preferable to use a polymer rubber. In the step of filling the conductive resin, it is preferable to perform the above-described push-in process using a squeegee or the like or a defoaming process by reducing pressure in order to prevent conduction failure or drop-off of the probe terminals, and can control the curing characteristics. It is preferable to use a thermosetting resin or a photo-setting resin. Further, it is particularly effective to increase the conductivity in a desired conduction direction by applying a magnetic field after containing the conductive particles.

In the probe terminal described above, the conductive contact with a conductive pad (for example, one formed of aluminum, one formed by coating a copper pattern with gold plating, etc.) formed on the surface of the substrate to be inspected, etc. It is preferable to cover the protruding and exposed end surfaces with a conductive material such as gold plating in order to improve the quality. Such coating with a conductive material can be easily applied by photolithography or the like.

The protruding amount of the probe terminal is determined by the coating layer (copper foil).
The thickness can be easily adjusted by changing the thickness. It is preferable that the protruding amount of the probe terminal is appropriately optimized according to the material of the probe terminal, the terminal interval, the terminal diameter, and the like.

[0045]

According to the present invention, a through hole is formed in a composite base material provided with a coating layer on the surface of an insulating base, and a conductive resin is filled therein and cured to form a probe terminal. By removing the coating layer, a probe terminal protruding from the surface of the insulating substrate by the thickness of the coating layer can be formed. However, it is possible to easily cope with this, and it is possible to manufacture at low cost.

[Brief description of the drawings]

FIGS. 1A to 1D are process explanatory views showing an embodiment of a method for manufacturing a probe head according to the present invention.

FIG. 2 is process explanatory diagrams (a) to (d) showing a filling step and a curing step of a conductive resin in the same embodiment.

FIG. 3 is a schematic cross-sectional view showing a test process of the probe head of the embodiment.

FIG. 4 is a schematic sectional view showing a state of inspection of a printed wiring board using the probe head manufactured according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Insulating substrate 11, 12 Copper foil 13 Probe terminal 15 Conductive resin 16 Squeegee 17 Heating plate 18, 19 Press block 20 Conductive plate 21 Test substrate 22 Press plate 23 Inspection board (printed circuit board)

Claims (5)

[Claims] 1. A step of forming a through-hole in the insulating base through the covering layer in a composite base having a coating layer on the surface of the insulating base, and applying a conductive resin to the through-hole. A method for manufacturing a probe head, comprising: a step of filling and curing to form a probe terminal made of a conductive resin; and a step of removing the coating layer. 2. The method according to claim 1, wherein, in the step of forming the through-hole, the inner surface of the through-hole is made uneven or roughened so as to be an engagement surface for engaging with the probe terminal. A method for manufacturing a probe head, comprising: 3. The method of manufacturing a probe head according to claim 1, wherein the insulating base is made of a synthetic resin containing fibers, and a part of the fibers protrudes from an inner surface of the through hole. . 4. The method according to claim 3, wherein the insulating base is made of a synthetic resin containing fibers woven therein. 5. The method according to claim 1, wherein the conductive resin is a synthetic rubber containing conductive particles.