JPH0476991A - Manufacture of printed circuit board - Google Patents

Abstract

PURPOSE:To uniformly fill conductive substance in a through hole, etc., of a printed circuit board stably by filling a filler in the hole of the board, and simultaneously coating a shielding layer with compressed air. CONSTITUTION:If conductive substance 8 is filled in a through hole 5 and coats a shield coating part 58, a nozzle end 15 is brought into contact with the upper surface of a mask 13, and horizontally moved. And, it is scanned at the hole 5 and the part 58 of a printed circuit board. An operating lever 22 is raised at the corresponding position against the elastic force of a spring 25 to open a discharge valve 23, the substance 8 to be fed under pressure is discharged from the end 15, the mask 13 is filled in, and the substance 8 is filled in the hole 5 and coats the part 58 through a coating hole 12 under pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a printed wiring board in which through-holes in the printed wiring board are filled with a conductive substance and a shield layer is applied simultaneously.

[Conventional technology]

Conventionally, conductive holes (through holes) in printed wiring boards
The filling method for filling a conductive substance with a conductive substance is to attach a conductive substance to a filling pin, and then insert it into a through hole formed in a printed wiring board so that it adheres to the outer periphery of the filling bottle. A method of attaching and filling a conductive substance into the through-holes, producing a silk plate for printing corresponding to the circuit design of a printed wiring board, and applying a conductive substance to the printed wiring board through this silk plate. A method of filling each through hole is adopted.

Furthermore, in the manufacture of conventional printed wiring boards, in addition to filling the through-holes with a conductive material, the deposition of shield layers, overcoats, etc. is performed in separate and independent operations.

That is, as shown in FIG. 4, printed circuits 61 and 62 of a desired circuit pattern are formed on both sides of an insulating substrate 60, and solder resists 63 and 64 are applied.

In addition, to form the through holes necessary for conduction between the printed circuits 61 and 62 between both surfaces of the substrate 60, the conductive holes 65 are opened by a process such as punching, and the through holes are formed in the conductive holes 65 by the method described above. Conductive substance 6
By filling G, printed circuits 61 and 62 on both sides of the insulating substrate 60 are electrically connected and formed.

Furthermore, when applying the shield layer 67 to the printed circuit 61, the solder resist 67 is applied by a printing method.
3. Apply a shielding material to the upper side and harden it to form a bulge.

Note that 68 is a ground circuit, and 69 is an overcoat that protects the shield layer 66.

[Problem to be solved by the invention]

However, in the former filling method using the bottle method in the conventional printed wiring board manufacturing method, the amount of conductive material adhering to the filling bottle is extremely small, and the through-hole In order to fill the inside with conductive material, the process of attaching the conductive substance to the filling bottle and inserting the attached bottle into each through hole of the printed wiring board must be repeated several times. However, in addition to the complexity of the work, the work efficiency is low.

Furthermore, in the above-mentioned work, the conductive material deposited in the through-hole in a filling bottle must be cured each time, which causes significant thermal damage to the material of the printed wiring board board. However, it has the disadvantage that the dimensional stability of the printed wiring board is significantly deteriorated.

Furthermore, if the printed wiring board has a large number of through holes, a large number of vials are required at a time, and it is usually impossible to use more than 1,000 vials, and the number of pins is limited due to the design. There are also restrictions on the size of the wiring board (
(Usually, it is not possible to use a cable with a size larger than 300m/m").

Therefore, the equipment 2 work process, such as manufacturing a bottle jig in which bottles are placed corresponding to each through hole of a printed wiring board, is difficult in terms of process and work, and has the disadvantage of being poor in mass production. have

In addition, in the case of the silk screen method, which is the conventional latter filling method, there is non-uniformity in the squeegee pressure against the screen, and when normal squeegee pressure is used, each through hole of the printed wiring board is completely conductive. It is difficult to fill the material with the substance, for example, if the thickness of the printed wiring board becomes thick or the diameter of the through hole becomes small, filling becomes impossible. (For example, with current technology, the plate thickness is 1
．． In the case of 6s, the diameter of the through hole is limited to 0.7 mmφ, and if the diameter becomes smaller than this, it is impossible to fill it with a conductive material).

In the case of such a method, the fluidity of the conductive substance greatly affects the uniformity of filling, which further increases the complexity of the work. Therefore, the fluidity of the conductive material is usually made uniform by adding a solvent to the conductive material, but on the other hand, the solvent is heated inside the through-hole when the conductive material hardens after filling. The solvent evaporates, causing a bubble accumulation phenomenon and the occurrence of cracks, resulting in poor conductivity and other problems, which poses a major problem in removing the solvent.

In other words, the solvent used to maintain the fluidity of the conductive material is a higher alcohol-based solvent that has a high boiling point and is difficult to vaporize. Time is required for complete evaporation of the solvent, and complete removal of the abrasion affects the integrity of the printed wiring board.

Furthermore, in addition to the method for manufacturing the through-holes, the application of the shield layer 67 is performed in a separate process, which increases the number of work steps.
0 and printed circuits 61, 62, etc., and it is desired to simplify the production of printed wiring boards.

Therefore, the present invention was developed in view of the shortcomings in the conventional printed wiring board manufacturing method, and it is possible to produce a conductive material without being affected by the thickness of the printed wiring board, the number of through holes, the diameter, etc. The object of the present invention is to provide a method for manufacturing a printed wiring board that can be filled uniformly and simultaneously form a shield layer.

[Means and effects for solving the problem] A method for manufacturing a printed wiring board of the present invention is a method for manufacturing a printed wiring board having through holes and a shield layer, in which the filling is performed in the through holes and the shield layer through a mask. The method is characterized in that compressed air is applied to the coating material, and the coating material is filled and coated while being press-fitted from a filling and coating nozzle, thereby simultaneously filling the through-hole with the filling material and depositing the shield layer.

〔Example〕

Embodiments of the method for manufacturing a printed wiring board of the present invention will be described below with reference to the drawings.

(First example) FIG. 1 is an explanatory diagram showing a first embodiment of the present invention.

In FIG. Connection lands 3 and 4 for electrically connecting the printed wiring circuit are arranged in the printed wiring circuit on both the front and back surfaces of the base Fi2, and both connection lands 3 and 4
It is constructed by punching (pressing) or drilling a through hole 5 in between.

Furthermore, under resists (solder resists) 6 and 7 are applied to the printed wiring circuits 56 on both the front and back surfaces of the substrate 2, but not to the ground circuit 57 of the shield layer.

Therefore, when filling the through holes 5 of the printed wiring board 1 having the above structure with the conductive substance 8 and applying the conductive substance 8 as a shielding material for forming a shield layer, the upper side of the pedestal 9 is The printed wiring board 1 is mounted and set on the upper side of the laid backing plate 10.

At this time, as shown in FIG. 1, the escape hole 11 of the backing plate 1o is aligned (aligned) with the through hole 5 of the printed wiring board l, and then the plate is inserted.

Further, on the upper side of the printed wiring board 1, a mask 13 having a through hole 12 for filling and coating is provided, and the through hole 12 for filling and coating is connected to the through hole 5 of the printed wiring Fj,1.
and the shield coating section 58 and set on board.

After that, a nozzle 14 for filling and applying the conductive substance 8 is installed above the mask 13 so as to be movable in the horizontal direction.
The conductive substance 8 is discharged from the nozzle end 15 of the mask 13 through the through hole 12 for filling and coating into the through hole 5 of the printed wiring board 1 and the shield coating section 58.
A conductive substance 8 is filled and applied to the conductive material 8.

The filling and coating nozzle 14 also includes a nozzle body 17 having a filling and coating portion 16 for the conductive substance 8, and a discharge valve operating portion 18 having an upper portion C of the filling and coating portion 16 of the nozzle body 17. It consists of

The filling and application section 16 is supplied with conductive material 8 through a supply port 19 from a supply section (not shown) for the conductive material 8.
is supplied to the discharge hole 2 of the filling and application section 16.
The nozzle end 15 is attached to the screw 21 in a removable manner.

Furthermore, a discharge pulp 23 is attached to the discharge hole 20 of the filling and application section 16 via an operating rod 22, and the upper end of the operating rod 22 is attached to a spring 25 in an operation chamber 24 provided at the upper part of the nozzle body 17. Operation valve 26 that is loaded with
is connected to.

Further, the operating chamber 24 of the operating section 18 is connected to an operating air pressure # (not shown) through a connecting port 27 via a control section (not shown).

Note that 28 is a slide bearing of the operating rod 22.

Therefore, the filling and coating nozzle 14 having the above configuration
When applying the conductive substance 8 to the inside of the through hole 5 and the shield application part 58 through the mask 13, the filling and application nozzle 14 is connected to the nozzle end 15 through the operation part (not shown). 13 to make contact with the upper surface and move it in the horizontal direction.

Then, while moving in the horizontal direction, the through holes 5 and the shield coating section 58 of the printed wiring board 1 are scanned, and the operating rod 22 of the operating section 1B is moved at the corresponding position.
The conductive substance 8 is raised against the bullet cam of the spring 25 to open the discharge valve 23 and open the discharge hole 20, and the conductive substance 8 is pumped into the filling and application section 16 from the connecting port 19 via the supply source. is discharged from nozzle #515, and the conductive material 8 is press-fitted into the through hole 5 and the shield coating portion 58 through the filling and coating hole 12 of the mask 13, and is filled and coated.

Incidentally, the conductive substance 8 press-fitted into the through hole 5 is exposed on the back side of the substrate 2 (8b), but this is not connected to the backing plate 10.
Since the exposed portion 8b is exposed in the relief hole 11, the bonding state between the exposed portion 8b and the connection land 4 on the back surface is completely ensured, and it is possible to avoid occurrence of electrical connection failure.

Further, it is desirable that the relief hole 11 of the backing plate IO has an inner diameter slightly larger than the diameter of the through hole 5.

Further, the mask 13 is made of a silk plate (for example, #180-3
00), other masks designed to prevent the conductive material 8 discharged from the filling and coating nozzle 14 from flowing out to positions other than those corresponding to the through holes 5 and the shield coating portion 58. can also be implemented.

Furthermore, in FIG. 1, one through hole 5 to be opened in the printed wiring Fi, l has been described, but it is also possible to fill and coat a plurality of through holes 5 in succession by the same method as described above. can.

Further, an example of filling conditions using the filling nozzle 14 will be listed below.

Scanning speed of filling nozzle: 10 ro/sec Printed wiring board thickness: 1.6 ■Through hole diameter
0.4 kakuφ injection pressure 6
．． 0 kg/cr1 Viscosity of conductive material 100
0 cps/25° C. Solvent-free copper paste was used as the conductive material.

Further, after filling under the above conditions, the conductive substance 8 in the through hole 5 was cured by drying in an oven heater at 150''C for 130 minutes, thereby forming a conductive circuit in the through hole 5.

(Second example) The second part is an explanatory diagram showing a second embodiment of the present invention.

In the case of this embodiment, the configuration of the filling and coating nozzle I4 used in the first embodiment is different,
Since the other methods are the same, the same reference numerals are given to the same constituent parts in the drawings, and a detailed explanation of the method will be omitted.

Thus, a squeegee 29 is attached to the side of the nozzle end 150 during the construction of the filling and coating nozzle 14.

This squeegee 29 also connects the filling and coating nozzle 14.
It is installed at the rear side in the horizontal movement direction of the vehicle.

Therefore, after the filling and coating nozzle 14 fills and coats the inside of the through hole 5 and the shield coating portion 58 with the conductive substance 8, the filling and coating nozzle 14 is horizontally moved. The conductive material 8 exposed above the through hole 5 and the shield coating section 5B through the squeegee 21 to which the squeegee 15 is attached can be removed by filling the mask 13 and applying through the coating hole 1242.

Note that the nozzle end 15 is attached using a screw 21 and can be replaced to select the size of the discharge hole 15a, but in consideration of the abrasion resistance of the surface that contacts the mask 13 and the protection of the mask 13. It is preferable to use plastic material or synthetic rubber, and the squeegee 2
It is desirable that consideration should also be given to material No. 9.

(Third example) FIG. 3 is an explanatory diagram showing a third embodiment of the present invention.

In the case of this embodiment, three substrates 31, 32 and 33 are used instead of the through holes 5 and shield coating portions 58 of the printed wiring board 1 having printed wiring circuits on both sides of the first embodiment. Through holes 3435 and connection holes 3 in a multilayer printed wiring board 30 laminated with
6 and a method for filling and applying the conductive substance 8 into the silt application section 58.

Now, each board 3132 and 33 of the printed wiring board 30 has printed wiring circuits 37, 38, 39 on both the front and back sides.
and 40, and connecting lands 4142, 43 and 44 for connecting the printed wiring circuits of each board 31, 32 and 33 to each other are arranged in the printed wiring circuit of each board 31, 32 and 33. , the respective through holes 34 and 35 connect to the connection lands 42.43 and connection lands 41.4 of the respective boards 31.32 and 33.
2.43 and 44, and the connection hole 36 is for electrically connecting the printed wiring circuit of the board 31, the connecting land 41 of the printed wiring circuit 37 on the front side, and the printed wiring circuit 38 on the back side. This is for electrical connection to the connection circuit 45.

Further, solder resists 46 and 47 covering the respective printed wiring circuits 37 and 40 are applied to the uppermost substrate 31 and the lowermost substrate 33 of the printed wiring board 30.

Furthermore, each of the through holes 34 and 35 are processed by punching or trilling, and the connecting hole 3
6 is processed by drilling a hole with a drill.

Therefore, when filling and applying the conductive substance 8 in each through hole 34, 35 and connection hole 36 and in the shield coating part 58 of the printed wiring board 30 having each of the above configurations, the same method as in the first embodiment is applied. A temporary plate 48 is mounted on the upper side of the stand 9, and a printed wiring board 3 is mounted on the upper side of this plate 48.
After setting the mask 49 on top of the printed wiring board 30, the filling and coating nozzle 14 is inserted through the mask 49 in the same manner as in the first embodiment.
and the through hole 35 from the shield application part 58 side.
It moves horizontally in the direction of the connection hole 36 to fill and apply the conductive substance 8 into the shield application portion 58, each through hole 34, 35, and the connection hole 36.

The patch plate 48 and the mask 49 also include through holes 34 and 35 of the printed wiring board 30 and connection holes 36.
An escape hole 5'0.51 and through holes 5253 and 54 for filling and coating are respectively arranged at positions corresponding to the arrangement positions of the relief hole 5'0.51 and filling and coating through holes 5253 and 54, respectively. 50, 51 and through holes 52, 53 and 54 for filling and coating on printed wiring board 3o.
The through holes 34, 35 and connection holes 36 are aligned with the shield application section 5 and set.

Further, as in the second embodiment, since the filling and coating nozzle 14 is equipped with a squeegee 29, the conductive material is filled in each through hole 34, 35 and connection hole 36 and in the shield coating portion 58. 8, the conductive material 8a exposed on the upper side can be filled and coated along each filling and coating through hole 52, 53, and 54 of the mask 49 while removing excess conductive material 8. .

Incidentally, in each of the above embodiments, filling with a conductive substance has been described, but other filling materials, such as a filling material for filling holes, can be similarly implemented.

According to the first to third embodiments described above, the filling and coating through-hole 12 of the mask 13 or 49 is filled and coated by the filling and coating nozzle 14. 52. The conductive substance 8 is press-fitted into the through holes 5, 34, 35 or the connection hole 36 and the shield coating part 58 through 53 and 54 while applying compressed air. By adjusting and controlling this, it becomes possible to fill small diameter holes without being influenced by the fluidity of the filler or the thickness of the substrate, and it is possible to improve the density of the circuit.

Furthermore, since the filling can be performed without being affected by the fluidity of the filler, there is no need to take measures such as adding a solvent to obtain appropriate fluidity of the conductive material; In other words, non-molten type filling can be achieved by press-fitting using a filling nozzle.

The nozzle end 15 of the filling and coating nozzle 14 is replaceable, and press-fitting can be performed uniformly and stably in accordance with the conditions for discharging the filler material, the diameter of the through hole, the thickness of the plate, etc.

Furthermore, since the filling is applied through a mask, it is possible to prevent filling into unnecessary areas and preventing the shielding material from adhering.

Further, it is possible to perform continuous filling and coating on the filling and coating locations corresponding to the circuit design of the printed wiring board, and it is possible to improve the workability of the filling and coating work.

〔Effect of the invention〕

As is clear from the above explanation, according to the method of manufacturing a printed wiring board of the present invention, there is no problem that is affected by the thickness of the printed wiring board, the diameter of the through hole, or the fluidity of the filler such as a conductive material. It is possible to uniformly and stably fill through holes and the like with a filler such as a conductive material, and at the same time, to apply a shield layer, thereby improving workability in manufacturing printed wiring boards.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams showing first to third embodiments of the filling method of the present invention, and FIG. 4 is an explanatory diagram showing a conventional printed wiring board. l, 30... Printed wiring board 2.31.32.33... Board 3.4, 41, 42, 43.44... Connection land 5.
34.35... Through hole 6.7... Under resist 8... Conductive material 9... Frame 10.48... Backing plate 11.50.51... Relief hole 12.52, 53,54.55 ...Filling and coating through hole 13.49...Mask 14...Filling and coating nozzle 15...Nozzle end 16...Filling and coating section 17...Nozzle body 18...Operation unit 19...Supply port 20...Discharge hole 21...Mounting with screw 22...Operation rod 23...Discharge valve 24...Operation chamber 25...Spring 26... ... Operation valve 27 ... Connection port 28 ... Slide bearing 29 ... Squeegee 36 ... Connection hole 37.38.39.40.56 ... Printed wiring circuit 45 ... Connection circuit 46. 47...Solder resist 57...Earth circuit 58...Shield application part

Claims (1)

[Scope of Claims] (1) A method for manufacturing a printed wiring board having through holes and a shield layer, the method comprising: inserting a mask into the through holes and the shield layer,
A printed wiring board characterized in that compressed air is applied to the filling and coating material, and the filling and coating material is filled and coated while being press-fitted from a filling and coating nozzle, and filling of the filler material in the through hole and application of the shield layer are performed simultaneously. Production method. (2) The printed wiring according to claim 1, wherein the mask uses a silk plate having through holes for filling and coating at positions corresponding to filling and coating positions of through holes etc. in the printed wiring board. Method of manufacturing the board. (3) The nozzle includes a filling and applying part for filling and applying material, a nozzle end at the tip of the filling and applying part, and an operation part for discharging the filling and applying material to the nozzle end in the filling and applying part. 2. The method of manufacturing a printed wiring board according to claim 1, further comprising using a nozzle having a filling part and a supply part for the coating material connected to each other. (4) The method for manufacturing a printed wiring board according to claim 1, characterized in that a patch plate corresponding to the mask is used. (5) The method for manufacturing a printed wiring board according to claim 1, wherein the filling and coating material is a solvent-free filling and coating material.