JP2003318520A - Method of filling hole bored in printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of filling a hole bored in a printed wiring board with resin which is capable of easily filling the hole with the resin, preventing the printed wiring board from deteriorating in quality due to residues of air bubbles, dispensing with a mask material forming process to simplify a filling process, and reducing the manufacturing cost of the printed wiring board. <P>SOLUTION: The method is to fill the holes X2 bored in the printed wiring board X with the resin R, and the resin R is extruded from the tip of a nozzle 23 to fill the hole X2. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of filling a resin into a hole such as a through hole formed in a printed wiring board, and more specifically, it can be easily filled with a resin and bubbles The present invention relates to a method for filling a hole in a printed wiring board that does not cause deterioration of quality due to residue.

[0002]

2. Description of the Related Art In recent years, in order to mount electronic parts at high density on a printed wiring board, through holes (holes) are filled with resin, and pads for mounting electronic parts are arranged on the through holes (so-called pad-on). Holes are being formed. Pads for mounting electronic components are generally provided in the vicinity of through-holes, but by providing them on such buried through-holes, the distance between through-holes can be narrowed, so the number of through-holes should be increased. Therefore, more electronic components can be mounted.

Conventionally, the resin filling into the through holes has been carried out by a screen printing method. With the backing plate arranged on the lower surface of the printed wiring board and the metal mask material having the positions corresponding to the through holes opened on the upper surface,
The screen printing machine imprints the resin into the through holes.

However, in the screen printing method described above, the number of imprints increases sharply (10 to several tens of times) in a printed wiring board having a thickness of more than 3.2 mm. , It takes a long time to fill the resin, and productivity is greatly deteriorated. At the same time, air is entrapped in the resin during imprinting, so more air is entrapped in the resin due to the increase in the number of imprinting, and it becomes bubbles. However, there is a problem in that the quality of the printed wiring board is adversely affected by the residual.

Further, it is necessary to manufacture a mask material for each printed wiring board, and for a design change in which the position of the hole is changed, a new mask material must be manufactured in accordance with the change. As a result, the work of filling the resin becomes complicated, which is one of the causes of increasing the manufacturing cost.

On the other hand, by embedding a plug-in hole (hole) formed in a build-up type printed wiring board with a resin and providing a pad for mounting electronic parts on the plug-in hole, the mounting density of electronic parts is increased. Is being done.

However, since the plug-in hole does not penetrate like the through-hole, when it is attempted to efficiently fill the resin by the screen printing method described above, air must remain in the plug-in hole filled with the resin. Not good, which adversely affects the quality. There is also a problem with the mask material.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for filling a hole in a printed wiring board, which allows easy filling of resin and does not cause quality deterioration due to residual air bubbles. To do.

Another object of the present invention is to provide a method of filling a hole in a printed wiring board, which simplifies the filling step by omitting the step of manufacturing a mask material and reduces the manufacturing cost. .

[0010]

The present invention which achieves the above object is a method of filling a resin into a hole portion of a printed wiring board, wherein the resin is extruded from a tip of a nozzle so that the resin is discharged into the hole. It is characterized in that the hole is filled by injecting into the inside of the part.

According to the above invention, the resin can be filled into the holes at one time even when the printed wiring board has a large thickness of more than 3.2 mm. It can be easily done and does not entrap air bubbles in the resin, and in the case of holes such as plug-in holes, it is possible to fill while letting air escape from the openings of the plug-in holes. Therefore, the quality of the printed wiring board does not deteriorate due to the remaining air bubbles.

Further, since the step of manufacturing the mask material is not required, the resin filling step can be simplified, thereby reducing the manufacturing cost.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The configuration of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an example of an apparatus used in the hole filling method for a printed wiring board according to the present invention, which is a pair of straight members extending in the front-rear direction (X direction) on the upper surface 1a of the base 1. Parallel guide grooves 2A and 2B are formed.
Mounting bodies 3A and 3B on which a printed wiring board filled with resin is mounted are slidably engaged with both guide grooves 2A and 2B. The mounts 3A and 3B are connected in the base 1,
A rodless cylinder (not shown) installed inside can move both in the guide grooves 2A and 2B in the X direction. A table T for mounting a printed wiring board, which is indicated by an alternate long and short dash line, is fixed between the mounting bodies 3A and 3B.

Plate-shaped left and right supports 4A and 4B are provided upright on both rear ends of the base 1.
A plurality of straight guide grooves 5 extending in parallel in the vertical direction are provided on the inner side surfaces 4a, 4b of the supports 4A, 4B that face each other.

A horizontal member 6 slidably engaged with the guide groove 5 is disposed between the left and right supports 4A and 4B, and the horizontal member 6 is guided along the guide groove 5 by an elevating means (not shown). It is possible to move up and down in the vertical direction (Z direction).

A pair of parallel guide grooves 7A and 7B extending straightly to the left and right are formed on the front surface 6a of the lateral body 6, and the resin pushing means 20 shown in FIG. 2 is formed in the guide grooves 7A and 7B. A mounting body 8 to be housed and attached is slidably engaged. The mounting body 8 is movable in the left-right lateral direction (Y direction) along the guide groove 5 by a rodless cylinder (not shown) installed in the horizontal body 6.

The mounting body 8 has a door 8a on its side for inserting and removing the resin pushing means 20. A hose 9 connected to a pressure supply source (not shown) for supplying a gas such as pressurized air to the resin extruding means 20 is connected to the top of the mounting body 8.

The resin extruding means 20, as shown in FIG.
Cylindrical resin container 22 in which piston 21 is slidably mounted
have. The resin container 22 is made of transparent resin, and a resin nozzle 23 is detachably attached to the tip of the resin container 22. The nozzle 23 has a tip inner diameter d
Is larger than the diameter D of the through hole X2 (Fig. 3
reference). The nozzle 23 has a conical shape in which the tip end side is gradually narrowed in the drawing, but may be a columnar shape.

Resin pushing means 20 housed in the mounting body 8
Is a resin container 2 with a cap 10 connected to the hose 9.
2 is attached to the rear part (upper part of the drawing) and set at a predetermined position in the mounting body 8, so that the nozzle 23 is held below the mounting body 8 in a protruding state.

When the pressurized gas is supplied to the resin container 22 through the hose 9, the pressure of the gas applied to the piston 21 moves the piston 21 to the nozzle 23 side, whereby the nozzle 23 The resin R contained in the resin container 22 is pushed out from the tip.

Reference numeral 11 denotes a control unit for controlling the above device,
A rodless cylinder (not shown) for moving the mounting bodies 3A and 3B, an elevating means (not shown) for elevating and lowering the lateral body 6, a rodless cylinder (not shown) for moving the mounting body 8, and a resin extruding means for pressurizing gas. A pressure supply source (not shown) to be supplied to 20 is sequentially controlled by a preset program so that a plurality of through holes formed in each printed wiring board can be sequentially filled with resin.

The method of the present invention for filling the through holes (holes) with the resin using the above-mentioned apparatus will be described below with reference to FIG.

First, the printed wiring board is set on the table T, and then the above device is operated. Placers 3A, 3
When B moves to a position below the mounting body 8 and a sensor (not shown) detects that the printed wiring boards on the mounting bodies 3A and 3B have reached a predetermined position, the horizontal body 6 descends and the nozzle 23 3A, the through hole opening surface X1 of the printed wiring board X is covered with the through hole X2 as shown in FIG. 3A, so that the through hole opening surface X1 and the tip of the nozzle 23 can ensure the sealing property. Low pressure (0.0009
The pressure is about 8 to 0.0098 MPa).

In the figure, S is a conductive layer that is conductively plated on the surface of the printed wiring board X and in the through holes X2.

Subsequently, gas is supplied into the resin container 22 for a predetermined time, and the pressure of the gas causes the piston 21 to descend by a predetermined amount to push out the resin R in the resin container 22 from the tip of the nozzle 23. The extruded resin R is injected into the through hole X2 and fills the through hole X2 as shown in FIG.

When the filling of the resin R is completed, the horizontal member 6 rises, and when the mounting member 8 moves to the position where the next through hole is located next to the horizontal member 6, the horizontal member 6 descends again to carry out the above-mentioned steps. To do.

According to the present invention described above, the resin R is extruded from the tip of the nozzle 23 so as to be injected into the through hole X2 of the printed wiring board X to fill the hole, so that the wall thickness is 3.2 mm. Even if the printed wiring board is thicker than the above, the resin R can be filled into the through hole X2 at one time, so that the resin R can be easily filled, and bubbles can be formed in the resin R. Since it is not caught, the quality of the printed wiring board X is not adversely affected.

Further, since the step of manufacturing the mask material can be omitted, the resin filling step can be simplified and the manufacturing cost can be reduced.

Further, the inner diameter d of the tip of the nozzle 23 is made larger than the diameter D of the through hole X2, the tip of the nozzle 23 is contacted so as to cover the through hole X2, and then the resin R is injected. Since it is possible to fill the through hole X2 with the resin R without causing a wide leak to the periphery of the through hole X2, the subsequent polishing process for removing the leaked resin by polishing is not complicated. In addition, resin R is applied to the through holes around the through hole X2 that are not filled.
Can be avoided.

In the above embodiment, when one through hole X2 is filled with the nozzle 23 as described above, the relationship between the inner diameter d of the tip of the nozzle 23 and the diameter D of the through hole X2 is D <d ≦. It is preferably 2D. If the tip inner diameter d is D or less, the resin may leak around the through hole X2 filled with the resin R. On the contrary, if the tip inner diameter d exceeds 2D, there is a risk that the tip of the nozzle 23 is applied to the adjacent through hole. is there.

As the resin R filled in the through hole X2, any resin may be used as long as it is a resin conventionally used for filling a hole in a through hole, for example, a thermosetting resin or an ultraviolet ray. Curable resin etc. can be mentioned.

As the thermosetting resin, for example, epoxy resin can be preferably used. As the ultraviolet curable resin, an epoxy resin that is cured by ultraviolet rays can be preferably used.

Further, it may be a composite resin containing fine hollow spheres made of glass or the like in the resin, or a composite resin in which alumina powder is dispersed in the resin. Further, a conductive type resin in which the above resin is used as a binder for metal fine particles such as copper powder or silver powder can also be used.

The viscosity of the resin is 15 to 105 Pa.
It can be s / 25 ° C. Viscosity is 15 Pa · s /
If the temperature is lower than 25 ° C, the viscosity becomes too low, and the liquid (resin) cannot be cut off at the nozzle tip after filling the hole, and as a result, the through hole opening from the nozzle tip while moving to the position where the next through hole is located. Resin drips on the surface X1,
The post-treatment polishing step becomes complicated. Conversely, 105 Pa · s /
If the temperature is higher than 25 ° C, the viscosity is too high, and it becomes difficult to efficiently fill the resin into the through hole X2. It is preferably 30 to 50 Pa · s / 25 ° C.

The discharge pressure of resin at the tip of the nozzle is
It is preferable to set it to 1.0 × 10 ^{5 to} 3.0 × 10 ⁵ Pa.
When the discharge pressure is lower than 1.0 × 10 ⁵ Pa, it becomes difficult to discharge the resin when the viscosity of the resin is set in the high range above. On the contrary, when the viscosity is higher than 3.0 × 10 ⁵ Pa, the resin tends to be excessively ejected when the viscosity of the resin is set in the low range. This discharge pressure is preferably selected as appropriate depending on the thickness of the printed wiring board, the diameter of the through hole, and the viscosity.

In the above embodiment, the resin R is filled in one through hole X2 by the nozzle 23.
A plurality of adjacent (for example, 2 to 3) through holes may be filled at the same time, whereby the filling efficiency of the resin R can be increased. In that case, the inner diameter d of the tip of the nozzle 23 should be long enough to cover the plurality of through holes.

FIG. 4 shows a case in which the plug-in hole (hole portion) Y1 formed in the build-up type printed wiring board Y by the filling method of the present invention is filled with resin by using the above-mentioned apparatus.

The outer diameter d'of the tip of the nozzle 23 is smaller than the opening diameter D'of the plug-in hole Y1.
Then, the tip of the nozzle 23 is inserted into the plug-in hole Y1 of the printed wiring board Y set on the mounting bodies 3A and 3B, and then the resin is injected into the plug-in hole Y1 to fill the hole. In the figure, M is a conductive layer formed on the surface of the plug-in hole Y1 and inside the substrate.

Unlike the through hole, the plug-in hole Y1 does not penetrate, so that it was difficult for air to remain in the plug-in hole Y1 and to fill the resin without a gap in the screen printing method. By extruding the resin from the tip and injecting it into the plug-in hole Y1, it is possible to fill the air in the plug-in hole Y1 while letting it escape from the opening, so that the resin is not left in the plug-in hole Y1. Can be easily filled.

Further, since the step of manufacturing the mask material can be omitted, the resin filling step can be simplified and the manufacturing cost can be reduced.

The same resin as described above can be used as the resin with which the plug-in hole Y1 is filled. Further, the viscosity and discharge pressure of the resin can be the same as described above, and can be appropriately selected depending on the diameter and depth of the plug-in hole Y1.

The present invention can be preferably used for filling the resin into the holes formed of the above-mentioned through holes and plug-in holes, but is not limited to this, and the resin is filled into the holes of the printed wiring board. If it exists, it can be suitably used for any of the holes.

[0044]

As described above, according to the present invention, the resin is extruded from the tip of the nozzle so that the resin is injected and filled in the hole portion. Therefore, the resin can be easily filled, and It is possible to avoid the deterioration of the quality of the printed wiring board due to the residual air bubbles, and to further reduce the manufacturing cost by omitting the step of manufacturing the mask material.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an apparatus used for a hole filling method for a printed wiring board according to the present invention.

FIG. 2 is an enlarged front view showing an example of a resin extruding means used in the hole filling method for the printed wiring board of the present invention.

FIG. 3 shows a case where a through hole is filled by a hole filling method for a printed wiring board according to the present invention, and FIG. 3A is an enlarged view of a main part showing a state in which a tip of a nozzle is brought into contact with a through hole portion of the printed wiring board. A sectional view, (b) is an enlarged sectional view of an essential part showing a state in which a through hole is filled with resin.

FIG. 4 is an enlarged sectional view of an essential part showing a case where a plug-in hole is filled by the hole filling method for a printed wiring board according to the present invention, showing a state in which the tip of the nozzle is inserted into the plug-in hole.

[Explanation of symbols]

1 base stand 2A, 2B guide groove 3A, 3B mounting body 4A, 4B support body 5 guide groove 6 lateral body 7A, 7B guide groove 8 mounting body 20 resin pushing means 21 piston 22 resin container 23 nozzle D through hole Diameter D'Plug-in hole opening diameter R Resin X, Y Printed wiring board X1 Through-hole opening surface X2 Through-hole (hole) Y1 Plug-in hole (hole) d Nozzle tip inner diameter d'Nozzle tip outer diameter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Osamu Kinoshita             141 Komakura, Kamakura City, Kanagawa Prefecture F-term (reference) 5E314 AA25 AA27 AA32 BB06 CC01                       EE01 FF08 GG17

Claims (4)

[Claims] 1. A method of filling a resin into a hole of a printed wiring board, the resin being extruded from the tip of a nozzle to inject the resin into the hole to fill the hole. Hole filling method. 2. The hole is a through hole, the inner diameter of the tip of the nozzle is made larger than the diameter of the through hole, and the tip of the nozzle is covered with the through hole opening surface of the printed wiring board to cover the through hole. 2. The resin is injected into the through hole after the contact is made as described above.
The method for filling a hole in a printed wiring board according to [4]. 3. The hole portion is a plug-in hole, the outer diameter of the tip of the nozzle is made smaller than the opening diameter of the plug-in hole, and the tip of the nozzle is inserted into the plug-in hole. The hole filling method for a printed wiring board according to claim 1, wherein resin is injected into the plug-in hole. 4. A resin extruding means having the nozzle attached to the tip of a cylindrical resin container containing a piston is used to apply gas pressure to the piston so that the resin container is housed in the resin container. The hole filling method for a printed wiring board according to claim 1, wherein resin is extruded from the tip of the nozzle.