JP3749201B2 - Method for manufacturing printed wiring board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a printed wiring board, which is mainly used in electronic equipment and the like, and is formed by laminating a plurality of insulating substrates having a conductor pattern on the surface.
[0002]
[Prior art]
Currently, printed wiring boards are used in all types of electronic equipment, from mass production equipment such as TVs to equipment that requires high reliability such as rockets, for the purpose of improving productivity, ensuring mass production quality, and improving reliability. Has been. In recent years, miniaturization and high-density mounting of electronic devices have progressed, and accordingly, there has been a demand for higher precision and higher density of printed wiring boards. A multilayer printed wiring board having a conductor pattern formed therein is also provided.
[0003]
Generally, this multilayer printed wiring board is formed as follows.
First, a plurality of large inner layer substrates having a plurality of conductor patterns are formed in advance on the surface of a large insulating substrate, and a prepreg and other large inner layers are formed on the surface of the large inner layer substrate. A board | substrate is mounted in order. Thereafter, the heating means is brought into contact with the peripheral portion of the surface, that is, the peripheral portion of the surface of the large insulating substrate on which the conductive pattern is not formed, the peripheral portion is heated, and the prepreg of the portion is cured. And temporarily fix. After that, the prepreg and the conductive material foil are sequentially placed on the temporarily fixed inner layer substrate surface, and then the entire surface of the prepreg is pressed and heated by a pressure bonding means such as a hydraulic press. It is melted and cured to form a large substrate. Further, the conductive material foil provided on the surface of the large substrate is subjected to a process such as forming a plurality of conductor patterns by an appropriate method such as a subtractive method, and then forming a solder resist pattern, and then a predetermined pattern. The printed wiring board is formed by cutting at a position.
[0004]
Here, the temporary fixing is the above-mentioned large inner layer substrate, the prepreg, and the conductive material foil stacked in a plurality of layers and simply placed, and when placed under high temperature and high pressure by a crimping means, the molten This is for determining the position after stacking to some extent because a positional shift or the like is caused due to the flow of the prepreg and the like and it cannot be formed with high accuracy.
[0005]
[Problems to be solved by the invention]
However, according to the conventional method for manufacturing a printed wiring board, when the temporary fixing is performed, the heating means is brought into direct contact with the peripheral portion of the insulating substrate on the surface of the inner layer substrate. Due to the surface roughness of the part, it was difficult to maintain the contact state uniformly. As a result, the melted and cured state of the prepreg at the peripheral edge portion of the insulating substrate becomes non-uniform, and it is difficult to form the thickness of the entire printed wiring board in the stacking direction substantially uniformly, that is, with high accuracy. There was a problem that there was.
[0006]
Further, in the portion where the prepreg has been melted due to the non-uniform contact state, the melted resin reaches the vicinity of the conductor pattern, that is, the portion that becomes the printed wiring board by the cutting. There was a case. In this case, there has been a problem that delamination occurs due to the thermal strain generated in the product because the cured state of the insulating substrate constituting the printed wiring board becomes uneven.
[0007]
Further, even if the melted and cured state is not uniform, even if it is uniform, there is a difference in the cured state between the peripheral portion of the prepreg and the insulating substrate. For this reason, in the process after crimping by the crimping means, due to the thermal strain generated in the large substrate, a crack occurs in a portion having a difference in the cured state, and further, between the insulating substrates. There was a problem that peeling occurred.
[0008]
The present invention has been made in view of such circumstances, and provides a method for manufacturing a printed wiring board that can be satisfactorily formed without causing manufacturing defects when the printed wiring board is manufactured. The purpose is to do.
[0009]
[Means for Solving the Problems]
In order to solve the above problems and achieve such an object, the present invention proposes the following means.
According to a first aspect of the present invention, there is provided a step of manufacturing a plurality of first substrates each having a first conductor pattern formed inside the surface of the first insulating substrate, and a step between the first substrates. After placing one prepreg, the outer peripheral edge on the first substrate and the surface of the first prepreg is heated by a heating means, thereby melting the first prepreg at the outer peripheral edge. A printed wiring board comprising: curing, temporarily fixing the first substrates at the outer peripheral edge, and cutting a predetermined position between the first conductor pattern and the outer peripheral edge In the manufacturing method, one or a plurality of protrusions are formed at substantially the same height on the outer peripheral edge of at least one surface of the first insulating substrate, and when heating, with placing the heating means on said protrusion, said first insulating substrate Between the projections of the surface and the predetermined position, and forming a wall member which continuously arranged substantially in parallel with the side surface of the first insulating substrate.
[0010]
According to the method of manufacturing a printed wiring board according to the present invention, since the protrusion comes into contact with the heating unit, the gap between the heating unit and the first substrate is set at the outer peripheral edge. It becomes possible to keep substantially constant, and it becomes possible to heat this outer periphery part uniformly. That is, the melted and cured state of the first prepreg can be made substantially uniform at the outer peripheral edge. Furthermore, since the heating means makes point contact with the protrusions, the heating from the heating means to the first substrate and the first prepreg can be efficiently and reliably performed.
Moreover, according to the method for manufacturing a printed wiring board according to the present invention, the first prepreg is provided between the first substrates, and the outer peripheral edge portions of these surfaces are heated to thereby provide the first prepreg. When the substrates are bonded together, the wall surface body prevents the molten first prepreg from flowing into the first conductor pattern side. Therefore, when forming the printed wiring board by cutting the large printed wiring board at a predetermined position, if the wall surface body is provided between the protrusion and the predetermined position, the printed wiring Since it becomes possible to make the cured state uniform in the insulating substrate constituting the board, it is possible to suppress delamination caused by thermal strain applied to the printed wiring board.
[0013]
The invention according to claim 2 is the method for manufacturing a printed wiring board according to claim 1, wherein a plurality of the first substrates are manufactured separately, and the first substrate is interposed between the first substrates. The first prepreg is placed so as to come into contact with the other surface of the substrate, the heating means is brought into contact with the protrusion, and the outer peripheral edge on the surface of the first substrate and the first prepreg A first substrate is heated, the first prepreg at the outer peripheral edge is melted and cured, and the outer peripheral edge between the first substrates is temporarily fixed to form a second substrate. To do.
[0014]
According to the method for manufacturing a printed wiring board according to the present invention, the heating means is brought into contact with the plurality of protrusions, and the first prepreg at the outer peripheral edge is heated and melted. For this reason, it becomes possible to make the said 1st prepreg the melting | fusing and hardening state in the said outer periphery part uniform. Therefore, since the thickness of the first substrate in the stacking direction can be formed substantially uniformly, a printed wiring board can be manufactured with high accuracy.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram for explaining a method of manufacturing a printed wiring board shown as one embodiment of the present invention, FIG. 2 is a plan view in the process shown in FIG. 1 (A), and FIG. The top view in the process shown to E) is shown.
[0020]
First, as shown in FIG. 1 (A) and FIG. 2, a plurality of inner layer conductor patterns 2 are formed on the surface of the first insulating substrate 1 having a copper foil attached to the surface by an appropriate method such as a subtractive method. At the same time, a plurality of protrusions 3 are formed on one surface of the first insulating substrate 1 at approximately the same height at each of the outer peripheral edge portions of the plurality of inner layer conductor patterns 2. At this time, a wall surface body 4 is formed between the inner layer conductor pattern 2 and the protrusions 3 so as to be connected substantially parallel to the side surface of the first insulating substrate 1, thereby forming the inner layer substrate 10.
[0021]
After the plurality of inner layer substrates 10 are formed separately, as shown in FIG. 1B, the first prepreg 11 is formed between the other surfaces of the inner layer substrate 10, that is, the surfaces where the protrusions 3 are not formed. After that, the heating means 20 is brought into contact with the protrusion 3. At this time, on the surfaces of the inner layer substrate 10 and the first prepreg 11, the outer peripheral edge portion of the inner layer conductor pattern 2 is heated to melt and harden the first prepreg 11 of the portion, and the inner layer substrates 10 of the portion Is attached to form a temporary fixing substrate 12.
At this time, the gap between the heating means 20 and the surface of the inner layer substrate 10 is substantially uniform over the entire outer peripheral edge because the heating means 20 is in contact with the protrusion 3. Furthermore, since the wall surface body 4 is provided between the inner layer conductor pattern 2 and the protrusions 3, the melted first prepreg 11 does not flow from the wall surface body 4 to the inner layer conductor pattern 2 side.
[0022]
Then, after the heating means 20 is separated from the protrusion 3, the second prepreg 13 and the copper foil 14 are sequentially placed on the surface of the temporary fixing substrate 12 as shown in FIG. These surfaces are pressurized and heated by a crimping means (not shown). As a result, the entire first and second prepregs 11 and 13 are melted and cured to form second and third insulating substrates 21 and 22, respectively, and the inner layer substrates 10 and the copper foil 14 are respectively applied to the entire surface. The laminated substrate 15 is formed.
[0023]
Thereafter, as shown in FIGS. 1D and 3, a plurality of through holes 16 arranged along the side surface of the multilayer substrate 15 between the protrusions 3 and the inner conductor pattern 2 on the surface of the multilayer substrate 15. After that, electroless copper plating is performed to form a copper plating layer 17 on the inner wall surface of the through hole 16 (the through hole 16 provided with the copper plating layer 17 on the inner wall surface is hereinafter referred to as “plating through hole 23”. "). Thereafter, on the surface of the multilayer substrate 15 by an appropriate method such as a subtractive method, the main outer layer conductor pattern 18 and the opening peripheral edge of the through hole 16 are formed on the surface of the third insulating substrate 22 as shown in FIG. Then, the sub-outer layer conductor pattern 19 is formed, and a large printed wiring board 30 is formed. Here, the sub-outer layer conductor pattern 19 and the copper plating layer 17 are electrically connected.
[0024]
And after giving predetermined processes, such as forming a soldering resist pattern, to the surface of large printed wiring board 30, as shown in Drawing 1 (E) and Drawing 3, inner layer conductor pattern 2 and main outer layer conductor pattern A printed wiring board 40 is formed by cutting at a predetermined position L1 between the conductor pattern 18 and the sub-outer layer conductor pattern 19 and by cutting a predetermined position L2 of the outer peripheral edge of the conductor patterns 2 and 18. The
[0025]
As described above, according to the method for manufacturing a printed wiring board according to the present embodiment, the plurality of protrusions 3 are provided at substantially the same height at various locations on the outer peripheral edge of the inner layer conductor pattern 2 in the inner layer substrate 10. Form with. For this reason, when the temporary fixing substrate 12 shown in FIG. 1B is formed, the heating means 20 is in contact with the protrusion 3, and the gap between the heating means 20 and the surface of the inner layer substrate 10 is the temporary fixing substrate 12. It becomes substantially uniform over the entire periphery of the surface. Accordingly, it is possible to make the melted and cured state of the first prepreg 11 at the peripheral edge uniform. Thereby, it becomes possible to form the thickness of the printed wiring board 40 to be formed in a substantially uniform thickness.
[0026]
Further, since the wall surface body 4 is formed between the inner layer conductor pattern 2 and the protrusion 3 on the surface of the inner layer substrate 10 so as to be substantially parallel to the side surface of the first insulating substrate 1, FIG. In forming the temporary fixing substrate 12 and the laminated substrate 15 shown in B) and (C), the melted first and second prepregs 11 and 13 are formed from the wall surface body 4 on the inner layer conductor pattern 2 side, that is, by the above cutting. It does not flow into the printed wiring board 40. Accordingly, the portion that is cured when the temporary fixing substrate 12 is formed is not included in the second insulating substrate 21 that constitutes the printed wiring board 40, so that the cured state of the insulating substrate 21 can be made substantially uniform. It becomes possible. Thereby, it becomes possible to suppress the occurrence of delamination due to thermal strain that occurs when the printed wiring board 40 is used.
[0027]
Furthermore, on the surface of the large printed wiring board 30 shown in FIG. 1E, a plurality of lines arranged along the side surface of the large printed wiring board 30 between the inner layer conductor pattern 2 and the protrusions 3. The plated through hole 23 is formed. As a result, the first insulating substrate 1 and the second insulating substrate at the peripheral edge due to thermal strain generated in the large printed wiring board 30 in a predetermined process after the large printed wiring board 30 is formed. The copper plating layer 17 acts as a resistance against delamination with 21. Accordingly, the first insulating substrate 1 and the second insulating substrate 1 at the peripheral edge due to the difference in the cured state between the peripheral edge of the second insulating substrate 21 and the portion other than the peripheral edge that occurs when the temporary fixing substrate 12 is formed. It becomes possible to suppress delamination from the insulating substrate 21.
In addition, since the sub-outer layer conductor pattern 19 that is electrically connected to the copper plating layer 17 is formed on the peripheral edge of the opening of the plating through hole 23 on the surface of the third insulating substrate 22, a further effect of suppressing the peeling is obtained. It is done.
[0028]
In the present embodiment, when the protrusion 3 and the wall surface body 4 are formed on the surface of the inner layer substrate 10, the inner layer conductor pattern 2 is formed simultaneously with the copper foil adhered to the surface of the insulating substrate 1. However, the present invention is not limited to this embodiment, and the function of the heating means 20 is not changed as long as the protrusion is in contact with the surface of the inner layer substrate 10 and the wall surface body in which the molten prepreg does not flow into the conductor pattern side.
[0029]
【The invention's effect】
As is clear from the above description, according to the invention of claim 1, the melted and cured state of the first prepreg can be made substantially uniform at the outer peripheral edge. Furthermore, since the heating means makes point contact with the protrusions, the heating from the heating means to the first substrate and the first prepreg can be efficiently and reliably performed.
Further, according to the invention according to claim 1, since it becomes possible to make the cured state uniform in each insulating substrate constituting the printed wiring board, delamination due to thermal strain received by the printed wiring board Can be suppressed.
[0031]
According to the second aspect of the present invention, it is possible to make the first prepreg melted and cured in the outer peripheral edge portion uniform. Therefore, since the thickness of the first substrate in the stacking direction can be formed substantially uniformly, a printed wiring board can be manufactured with high accuracy.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining a method of manufacturing a printed wiring board shown as an embodiment of the present invention.
FIG. 2 is a plan view of FIG.
FIG. 3 is a plan view of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st insulating substrate 2 Inner layer conductor pattern (1st conductor pattern) 3 Protrusion body 4 Wall surface body 10 Inner layer board | substrate (1st board | substrate) 11 1st prepreg 12 Temporary fix board | substrate (2nd board | substrate) 13 2nd Pre-preg 14 Copper foil (conductive material foil) 15 Laminated substrate 16 Through hole 17 Copper plating layer (plating layer) 18 Main outer layer conductor pattern (second conductor pattern) 19 Sub outer layer conductor pattern (third conductor pattern) 20 Heating Means 21 Second insulating substrate 22 Third insulating substrate 40 Printed wiring board

Claims (2)

After manufacturing a plurality of first substrates each having a first conductor pattern formed inside the surface of the first insulating substrate, and placing the first prepreg between the first substrates The outer peripheral edge on the surface of the first substrate and the first prepreg is heated by a heating means to melt and cure the first prepreg of the outer peripheral edge, and the outer peripheral edge A method of manufacturing a printed wiring board including a step of temporarily fixing the first substrates to each other and a step of cutting a predetermined position between the first conductor pattern and the outer peripheral edge,
One or a plurality of protrusions are formed at substantially the same height on the outer peripheral edge of at least one surface of the first insulating substrate, and the heating is performed on the protrusions during the heating. A heating means is mounted , and a wall surface body is formed between the protrusion on the surface of the first insulating substrate and the predetermined position so as to be connected substantially in parallel with the side surface of the first insulating substrate. A method for producing a printed wiring board. It is a manufacturing method of the printed wiring board according to claim 1,
A plurality of the first substrates are manufactured separately,
Between the first substrates, the first prepreg is placed so as to be in contact with the other surface of the first substrate,
The heating means is brought into contact with the protrusion, the outer peripheral edge portion on the surface of the first substrate and the first prepreg is heated, and the first prepreg at the outer peripheral edge portion is melted, A method of manufacturing a printed wiring board, comprising: curing and temporarily fixing the outer peripheral edges of the first substrates to form a second substrate.

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