JP2004039809A - Multilayered circuit board and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To match impedance by making each thickness of a multilayered circuit board equal. <P>SOLUTION: The multilayered circuit board is provided with a non-compression insulating base material 102 and a wiring pattern 105 between compression insulating base materials 101 with an adhesive layer 101a formed on the surface. When the multilayered circuit board is manufactured by heating and pressurizing the non-compression insulating base material 102, the wiring pattern 105 and the compression insulating base material 101, the thickness before heating and pressurization of the compression insulating base material 101 is set in proportion to size of a pattern gap 110 of the wiring pattern 105. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multilayer circuit board and a method for manufacturing the same.
[0002]
[Prior art]
An ALIVH (Any Layer Inner Via Hole) substrate is known as a multilayer wiring substrate for electrically connecting layers by using a conductive paste (Japanese Patent No. 26001128).
[0003]
The manufacturing process of the ALIVH substrate will be described.
[0004]
As shown in FIG. 4A, a film in which an adhesive layer 402 is formed on one surface of a release film 401 such as polyethylene terephthalate (PET) (hereinafter referred to as an adhesive film) is prepared. Also, a porous substrate (hereinafter, referred to as a prepreg) 403 in which an aromatic polyamide fiber is impregnated with a thermosetting epoxy resin is prepared. Then, as shown in FIG. 4B, the adhesive film is laminated on both surfaces of the prepreg 403.
[0005]
Next, as shown in FIG. 4C, a through hole 404 is formed at a predetermined position of the prepreg 403 by a laser processing method. Next, as shown in FIG. 4D, the through-hole 404 is filled with a conductive paste 405 made of copper powder and epoxy resin.
[0006]
As a method for filling the conductive paste 405, for example, the following method is available. A prepreg 403 having a through hole 404 is set on a table of a screen printing machine, and a conductive pace 405 is formed by printing directly on the release film 401. At that time, the release film 401 on the printing surface plays a role of a print mask and a role of preventing surface contamination of the prepreg 403.
[0007]
Next, the release film 401 is peeled off from both sides of the prepreg 403 as shown in FIG. Next, a metal foil 406 such as a copper foil is laminated on both surfaces of the prepreg 403. In this state, the prepreg 403 and the metal foil 406 are heated and pressed. Thereby, as shown in FIG. 4F, the prepreg 403 and the metal foil 406 are bonded.
[0008]
At this time, the prepreg 403 and the conductive paste 405 in the through holes 404 are compressed by a heating and pressing process. Therefore, the binder component in the conductive paste 405 is extruded into the prepreg 403. Thereby, the bond between the copper powders and between the copper powder and the metal foil 406 are strengthened, the density of the copper powder in the conductive paste 405 is increased, and electrical connection between the layers is obtained. After that, the thermosetting resin, which is a component of the prepreg 403, and the resin component of the conductive paste 405 are cured.
[0009]
Next, as shown in FIG. 4G, the metal foil 406 is selectively etched into a predetermined pattern, thereby completing a double-sided wiring board.
[0010]
Using the prepared double-sided wiring board as a core material (base), the prepreg 403 obtained by the manufacturing method of FIGS. 4A to 4E is aligned on both sides of the core material, and copper Place the foil. Then, the core material (base), the prepreg 403, and the copper foil are again heated and pressed by a hot press machine to perform lamination and multilayering, and finally, the copper foil is etched and patterned. Thus, a four-layer multilayer circuit board is obtained.
[0011]
Further, when multi-layering is required, the four-layered multilayer circuit board is used as a core material (base), and the above-described steps are repeated again to obtain a six-layered or eight-layered multilayer circuit board.
[0012]
[Problems to be solved by the invention]
However, the multilayer circuit board manufactured by the above-described conventional manufacturing method has a problem that it is difficult to achieve impedance matching between wirings. This will be described below.
[0013]
The impedance of the wiring pattern of each layer in the multilayer circuit board depends on the thickness of each insulating layer, which is the spacing between the wiring patterns in the thickness direction of the board. The thickness of each insulating layer is ultimately determined by how much each prepreg 403 constituting the insulating layer is compressed during the manufacturing process. Strictly speaking, the degree of compression of each prepreg 403 depends on the pattern remaining ratio of the wiring pattern facing each prepreg 403. This will be described below.
[0014]
First, the pattern remaining rate will be described. The wiring pattern is formed by forming a metal foil (copper foil or the like) on the entire surface of the substrate and then performing a photolithography process or the like to remove an excess foil portion. Based on such a manufacturing process, an area ratio of the wiring pattern remaining on the substrate per unit area is referred to as a pattern remaining ratio.
[0015]
In a wiring pattern having a low pattern remaining ratio, the volume of a pattern gap existing between wiring patterns adjacent in the planar direction becomes large. Conversely, in a wiring pattern having a high pattern remaining ratio, the volume of the pattern gap becomes small.
[0016]
When manufacturing a multilayer circuit board, the adhesive layer 402 enters into the pattern gap of the wiring pattern and is integrated with the wiring pattern. Therefore, each prepreg 403 is apparently compressed by the adhesive layer 402 entering the pattern gap. When a wiring pattern having a low pattern remaining ratio is provided, the apparent compression amount becomes large. Conversely, when a wiring pattern having a low pattern remaining ratio is provided, the apparent compression amount becomes small.
[0017]
On the other hand, the pattern remaining ratio of the wiring pattern formed on the prepreg 403 is usually not the same in each of the prepregs 403 and inevitably differs. Specifically, when the wiring pattern formed on the core material (double-sided substrate) in contact with the prepreg 403 is a power supply pattern or a ground pattern, the pattern remaining ratio is high. On the other hand, when the wiring pattern is a signal line pattern, the pattern remaining rate decreases.
[0018]
Therefore, such a difference in the pattern remaining ratio causes variations in the thickness of the substrate arranged between the wiring patterns, and as a result, impedance mismatch has occurred between the wirings in each layer.
[0019]
An object of the present invention is to provide a multilayer circuit board in which the impedance is matched in each wiring in consideration of the above conventional problems.
[0020]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a wiring pattern between a compressible insulating base material having an adhesive layer provided on a surface thereof and an incompressible insulating base material, A method for manufacturing a multilayer circuit board, wherein a material, the wiring pattern, and the incompressible insulating base material are heated and pressed to produce a multilayer circuit board.
A step of producing the compressible insulating base material whose thickness before heating and pressing is set according to the pattern remaining ratio of the wiring pattern,
A step of laminating the compressible insulating base material, the wiring pattern, and the non-compressible insulating base material, the thickness of which is set before the overheating and pressurizing by the above-mentioned process, and heating and pressing the same.
It is characterized by including.
[0021]
When the wiring pattern has a low residual pattern ratio, it is preferable to reduce the thickness of the compressible insulating base material before heating and pressing.
[0022]
If the wiring pattern has a high pattern remaining rate,
P0 = A / Cp
P0: thickness of the compressible insulating base material before heating and pressing
A: Thickness of incompressible insulating base material
Cp: compressibility of the compressible insulating substrate by heating and pressing
It is preferable to set the thickness of the compressible insulating base material before heating and pressurizing by the following calculation formula.
[0023]
When the pattern remaining rate of the wiring pattern is low,
P0 = A / Cp + B
P0: thickness of the compressible insulating base material before heating and pressing
A: Thickness of incompressible insulating base material
Cp: compressibility of the compressible insulating substrate by heating and pressing
B: thickness of wiring pattern
It is preferable to set the thickness of the compressible insulating base material before heating and pressurizing by the following calculation formula.
[0024]
In addition, another wiring having a low pattern remaining rate is provided via an adhesive layer on the surface of the compressible insulating base material where the pattern remaining rate of the wiring pattern is low and the incompressible base material is not in contact. When a pattern or metal foil is placed,
P0 = A / Cp + 2B
P0: thickness of the compressible insulating base material before heating and pressing
A: Thickness of incompressible insulating base material
Cp: compressibility of the compressible insulating substrate by heating and pressing
B: thickness of the wiring pattern and another wiring pattern
It is preferable to set the thickness of the compressible insulating base material before heating and pressurizing by the following calculation formula.
[0025]
In the case where another wiring pattern is arranged via an adhesive layer on the surface of the compressible insulating base material where the non-compressible base material is not in contact,
P0 = A / Cp + Bt (1-St) + Bb (1-Sb)
P0: thickness of the compressible insulating base material before hot pressing
A: Thickness of incompressible substrate
Cp: hot press compressibility of compressible substrate
Bt: thickness of wiring pattern
Bb: thickness of another wiring pattern
St: Pattern remaining rate of the wiring pattern
Sb: Pattern remaining rate of another wiring pattern
It is preferable to set the thickness of the compressible insulating base material before heating and pressurizing by the following calculation formula.
[0026]
In the case where another wiring pattern is arranged via an adhesive layer on the surface of the compressible insulating base material where the non-compressible base material is not in contact,
The thickness of the two adhesive layers is such that the relative ratio of the thickness of the two adhesive layers matches the reciprocal of the relative ratio between the pattern remaining ratio of the wiring pattern and the pattern remaining ratio of the another wiring pattern. Is preferably set.
[0027]
Thus, according to the present invention, it is possible to make the thicknesses of the substrates arranged between the respective wiring patterns coincide with each other, thereby suppressing the impedance mismatch between the wirings of the respective layers.
[0028]
Note that, in the present invention, the thickness of the compressible insulating base material is not limited to the thickness of the compressible insulating base material set by each of the above-described formulas, but may be a thickness close to the thickness set by each of the above-described formulas. It may be set as the thickness before hot pressing. As a category of the approximation here, a range of ± 10% of the thickness set by each equation is appropriate.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
1 (a) to 1 (c) are cross-sectional views illustrating the steps of manufacturing a multilayer circuit board having four layers according to Embodiment 1 of the method of manufacturing a multilayer circuit board of the present invention.
[0030]
In the present embodiment, the present invention is implemented in a method for manufacturing a multilayer circuit board described below. That is, a prepreg (compressible insulating base material having an adhesive layer 101a on both sides) 101 is placed between a pair of core materials (non-compressible insulating base material) 102 manufactured in advance based on a conventional ALIVH manufacturing method. The present embodiment embodies the present invention in a method of manufacturing a four-layer multilayer circuit board by laminating and bonding the core members 102 and 102 and the prepreg 101 with the interposition therebetween. The compression ratio Cp of the prepreg 101 by hot pressing (hereinafter, referred to as hot press compressibility) is defined by the following equation (1).
Cp = P / P0 (1)
P: thickness of the prepreg 101 after hot pressing
P0: thickness of prepreg 101 before hot pressing
In the present embodiment, first, a pair of core materials 102 and 102 and a single prepreg 101 are prepared. As the core members 102, a wiring pattern 105 having a high pattern remaining ratio such as a power supply pattern or a ground pattern (hereinafter, referred to as a power supply / ground pattern) is formed on one surface in advance, and a metal such as copper foil is formed on the other surface substantially on the front surface. The one on which the foil 104 is adhered is prepared. Note that the wiring pattern 105 having a high pattern remaining ratio in the present invention specifically refers to the wiring pattern 105 having a pattern remaining ratio of 50% or more. The wiring pattern 105 is formed, for example, by attaching a metal foil to the core material 102 and performing a photolithography process or the like on the attached metal foil. As the prepreg 101, one having an adhesive layer 101a formed on both surfaces is prepared. Note that the thickness P0 of the prepreg 101 before the hot pressing includes the thickness of the adhesive layer 101a. The pattern remaining ratio refers to the ratio of the area remaining as the wiring pattern to the area of the metal foil formed on the entire surface of the core material 102 or the like.
[0031]
Next, as shown in FIG. 1B, the prepreg 101 and the core material (double-sided substrate) 102 obtained by the above method are stacked and arranged. Here, the prepreg 101 and the core material 102 are stacked such that the wiring pattern 105 of each core material 102 faces the prepreg 101.
[0032]
A predetermined temperature and pressure are applied to the prepreg 101 and the core material 102 arranged in a stack for a predetermined time by a heating press or the like. By performing this step, the prepreg 101 is compressed to a completely cured state. For example, when an aramid epoxy resin is used as the prepreg 101, pressurization: 30 kg / cm ² The heating and pressurizing treatment is performed for one hour under the condition of heating and 180 ° C., so that the prepreg 101 is completely cured.
[0033]
Next, as shown in FIG. 1C, the surface layer wiring pattern 106 is formed by subjecting the metal foil 104 of the core material (double-sided substrate) 102 disposed on the outermost layer to a photolithography process or the like, which is a well-known technique. It is formed. Thus, a four-layered multilayer circuit board is completed.
[0034]
In the present embodiment in which a multilayer circuit board is manufactured through the above manufacturing steps, the thickness of the prepreg 101 is set as follows.
[0035]
In the present embodiment, a wiring pattern 105 having a high pattern remaining ratio, such as a power supply / ground pattern, is disposed on both sides of the prepreg 101 so as to face each other. Therefore, in the present embodiment, the thickness P0 of the prepreg 101 before hot pressing is set based on the following equation (2).
P0 = A / Cp (2)
P0: thickness of prepreg 101 before heating and pressing
A: thickness of core material 102
Cp: Hot press compression ratio of prepreg 101
In the equation (2), the thickness P0 of the prepreg 101 before hot pressing is set based on the following theory. First, the principle of compression of the prepreg 101 will be described. In the prepreg 101, the prepreg 101 itself is compressed by the heating and pressurizing treatment, and apparently compressed as follows.
[0036]
When the prepreg 101 and the core material 102 are pressed, the adhesive layer 101a provided on both surfaces of the prepreg 101 and the wiring pattern 105 facing the prepreg 101 are adhered to each other. At this time, the adhesive layer 101a comes into close contact with the wiring pattern 105 while entering the pattern gap 110 existing between the wiring patterns 105 adjacent in the planar direction. The prepreg 101 is apparently compressed by the penetration of the adhesive layer 101a into the pattern gap 110 as described above.
[0037]
In the wiring pattern 105 having a high pattern remaining ratio, the volume of the pattern gap 110 is small. Therefore, when the wiring pattern 105 whose pattern gap 110 is small in volume is opposed to both surfaces of the prepreg 101, the adhesive layer 101 a is less likely to be embedded in the wiring pattern 105. As a result, the apparent compression amount of the prepreg 101 due to the penetration of the adhesive layer 101a into the pattern gap 110 is reduced.
[0038]
Based on the compression theory of the prepreg 101, in a state where the wiring pattern 105 having a high pattern remaining ratio is arranged to face the prepreg 101, it can be considered that the apparent compression of the prepreg 101 hardly occurs. The compression amount of the prepreg 101 in this case can be regarded as almost only the compression amount caused by the compression of the prepreg 101 itself.
[0039]
Therefore, in the prepreg 101 in which such wiring patterns 105 are arranged to face each other, the amount of compression of the prepreg 101 by hot pressing is defined only by the thickness P of the prepreg 101 before hot pressing and the compression ratio Cp of the prepreg 101. Conceivable. The above equation (2) is set based on such a compression theory.
[0040]
For example, when the hot press compression ratio Cp of the prepreg 101 is 98% (0.98) and the thickness A of the insulating base material 103 in the core material (double-sided substrate) 102 is 98 μm, the prepreg 101 is obtained by the equation (2). The thickness P0 before hot pressing is
P0 = A / Cp = 98 / 0.98 = 100 (μm)
It becomes.
[0041]
Based on this calculation result, a prepreg 101 having a thickness P0 of 100 μm before hot pressing is prepared. By thus laminating and integrating the prepreg 101 and the core material 102 each having the thickness P0 before the hot pressing, a four-layer multilayer in which the thickness of each insulating base material 103 becomes uniform as designed. A circuit board is obtained.
[0042]
Furthermore, a multilayer circuit board having four or more layers can be formed using the multilayer circuit board having four layers obtained by the above method. In this case, first, the four-layer multilayer circuit board obtained by the above method is used as the core material 102, and the prepreg 101 is further laminated. Then, after the laminate is hot-pressed collectively, a pattern forming method such as a photolithography method is performed on the metal foil 104 located on the outermost layer, thereby forming the surface wiring pattern 106. . As a result, a five-layer or six-layer multilayer circuit board is obtained. When a multi-layered circuit board is required, the above manufacturing method is repeatedly performed.
[0043]
In the present embodiment, not only the thickness P0 before hot pressing set by the equation (2) but also the thickness P0 ′ close to the thickness P0 set by the equation (2) before the hot pressing of the prepreg 101 is used. May be set as the thickness. As the category of the approximation here, a range of ± 10% of the thickness P set by the equation (2) is appropriate.
[0044]
(Embodiment 2)
2 (a) to 2 (c) are cross-sectional views of a manufacturing process of a four-layer multilayer circuit board which is Embodiment 2 of the method of manufacturing a multilayer circuit board of the present invention.
[0045]
This embodiment is basically a method for manufacturing a multilayer circuit board similar to that of the first embodiment. However, the reference numerals assigned to the respective parts are in the 200s. That is, 201 is a prepreg, 201a is an adhesive layer, 202 is a core material, 203 is an insulating base material, 204 is a metal foil, 205 is a wiring pattern, and 210 is a pattern gap. is there.
[0046]
In the present embodiment, the thickness P0 of the prepreg 201 before hot pressing is set as follows.
[0047]
In this embodiment, a wiring pattern 205 having a low pattern remaining ratio, such as a signal line pattern, is disposed on both sides of the prepreg 201 so as to face each other. Therefore, in this embodiment, the thickness P0 of the prepreg 201 before hot pressing is set based on the following equation (3).
P0 = A / Cp + 2B (3)
P0: thickness of prepreg 201 before hot pressing
A: thickness of core material 102
Cp: Hot press compression ratio of prepreg 101
B: thickness of the wiring pattern 205
In the equation (3), the thickness of the prepreg 201 is set based on the following theory. As described in the first embodiment, the adhesive layer 201a comes into close contact with the wiring pattern 205 while entering the pattern gap 210 existing between the wiring patterns 205 adjacent in the plane direction. The prepreg 201 is apparently compressed by the adhesive layer 201a entering the pattern gap 210.
[0048]
In a wiring pattern 205 such as a signal line pattern having a low pattern remaining ratio, the pattern gap 210 is large in volume. Note that the wiring pattern 205 having a low pattern remaining ratio in the present invention specifically refers to the wiring pattern 205 having a pattern remaining ratio of less than 50%. Therefore, when the wiring pattern 205 having a large volume of the pattern gap 210 is opposed to both surfaces of the prepreg 201, the wiring pattern is easily embedded in the 205 adhesive layer 201a. As a result, the apparent compression amount of the prepreg 201 caused by the penetration of the adhesive layer 201a into the pattern gap 210 increases.
[0049]
Based on such a compression theory of the prepreg 201, in a state where the wiring pattern 205 such as a signal line pattern is arranged to face the prepreg 201, it can be considered that the apparent compression of the prepreg 201 is sufficiently generated. The amount of compression of the prepreg 201 in this case is the amount of compression caused by the compression of the prepreg 201 itself, and the amount of prepreg caused by the adhesive layers 101 a provided on both surfaces of the prepreg 201 entering the pattern gap 210. This is considered to be the sum of the apparent compression amounts 201. Here, the apparent compression amount of the prepreg 201 due to the penetration of the adhesive layer 201 a corresponds to the pattern thickness of the wiring pattern 205.
[0050]
Therefore, in the prepreg 201 in which such wiring patterns 205 are arranged to face each other, the amount of compression of the prepreg 201 by hot pressing depends on the thickness P of the prepreg 201 before hot pressing, the compression ratio Cp of the prepreg 201, and the adhesive layer 201a. This is considered to be the sum of the apparent compression amount of the prepreg 201 caused by the intrusion. The above equation (3) is set based on such a compression theory.
[0051]
For example, when the compression ratio Cp of the prepreg 201 is 98% (0.98), the thickness A of the base material 203 of the core material (double-sided substrate) 202 is 98 μm, and the thickness B of the wiring pattern 205 is 20 μm, According to the expression 3), the thickness of the prepreg 201 is
P = A / Cp + 2B = 98 / 0.98 + 2 × 20 = 140 (μm)
It becomes.
[0052]
Based on the calculation result, a prepreg 201 having a thickness P0 of 140 μm before hot pressing is prepared. Then, the prepreg 201 having the thickness P set before the hot pressing and the core material 202 are laminated and integrated to form a four-layer multilayer circuit board in which the interlayer thickness of each insulating base material 203 is uniform. Is obtained.
[0053]
Further, a method for manufacturing a multilayer circuit board having four or more layers using the multilayer circuit board having four layers obtained by the above method is the same as that described in the first embodiment. Also in the present embodiment, not only the thickness P set by the equation (3) but also the thickness P ′ approximate to the thickness set by the equation (3) is set as the thickness of the prepreg 201 before hot pressing. You may. As a category of the approximation here, a range of ± 10% of the thickness P set by the equation (3) is appropriate.
[0054]
(Embodiment 3)
3 (a) to 3 (c) are cross-sectional views illustrating a process for manufacturing a four-layered multilayer circuit board which is Embodiment 3 of the method for manufacturing a multilayer circuit board of the present invention.
[0055]
This embodiment is basically a method for manufacturing a multilayer circuit board similar to that of the first embodiment. However, the reference numerals assigned to the respective parts are in the 300s. That is, 301 is a prepreg, 301a is an adhesive layer, 302 is a core material, 303 is an insulating base material, 304 is a metal foil, and 305A is a wiring pattern such as a power / ground pattern. , 305B are wiring patterns such as signal line patterns, and 310 is a pattern gap.
[0056]
In the present embodiment, the thickness of the prepreg 301 is set as follows.
[0057]
In the present embodiment, a wiring pattern 305A having a high pattern retention ratio such as a power supply / ground pattern is disposed on one surface of the prepreg 301 and a wiring pattern 305B having a low pattern retention ratio such as a signal line pattern is disposed on the other surface. Be placed. Therefore, in the present embodiment, the thickness P0 of the prepreg 301 before hot pressing is set based on the following equation (4).
P0 = A / Cp + B (4)
P0: thickness of prepreg 301 before hot pressing
A: thickness of core material 302
Cp: hot press compressibility of prepreg 301
B: thickness of wiring patterns 305A and 305B
In the equation (4), the thickness of the prepreg 301 is set based on the following theory. As described in the first embodiment, the adhesive layer 301a comes into close contact with the wiring patterns 305A and 305B while entering the pattern gap 310 existing between the wiring patterns 305A and 305B adjacent in the plane direction. The prepreg 301 is apparently compressed by the penetration of the adhesive layer 301a into the pattern gap 310 as described above.
[0058]
In a wiring pattern 305B such as a signal line pattern having a low pattern remaining ratio, the pattern gap 310 is large in volume. On the other hand, in the wiring pattern 305A such as a power supply / pattern having a high pattern remaining ratio, the pattern gap 310 is small in volume. For this reason, in the configuration of the present embodiment in which the wiring pattern 305A is disposed to face one surface of the prepreg 301 and the wiring pattern 305B is disposed to face the other surface of the prepreg 301, the wiring pattern 305A is formed of the adhesive layer 301a. And the wiring pattern 305B is easily embedded in the adhesive layer 301a. As a result, the apparent compression amount of the prepreg 301 due to the entry of the adhesive layer 301a into the pattern gap 310 is about half the apparent compression amount in the second embodiment.
[0059]
Therefore, the prepreg 301 in the configuration of the present embodiment in which the wiring pattern 305 </ b> B such as a signal line pattern having a feature that the pattern gap 310 is large in volume due to a low pattern remaining rate is disposed only on one surface of the prepreg 301. Can be regarded as about half of the case where the wiring pattern 305B is provided on both sides.
[0060]
Therefore, the amount of compression of the prepreg 301 in this case is the amount of compression caused by the compression of the prepreg 301 itself, and the amount of compression of the prepreg 301 caused by the wiring pattern 305B entering the adhesive layer 301a on one side of the prepreg 301. It is considered that this is the sum of the apparent compression amounts 301. Here, the apparent compression amount of the prepreg 301 due to the entry of the wiring pattern 305B corresponds to the thickness of the wiring pattern 305B.
[0061]
Therefore, the compression amount of the prepreg 301 in the configuration of the present embodiment is obtained by adding the compression amount of the prepreg 301 itself and the apparent compression amount of the prepreg 301 caused by the wiring pattern 305B entering the adhesive layer 301a. It is considered something. The above equation (4) is set based on such a compression theory.
[0062]
For example, when the compression ratio Cp of the prepreg 301 is 98% (0.98), the thickness A of the base material 303 of the core material (double-sided substrate) 302 is 98 μm, and the thickness B of the wiring patterns 30A and 305B is 20 μm. According to the formula (4), the thickness P0 of the prepreg 301 before hot pressing is
P0 = A / Cp + B = 98 / 0.98 + 20 = 120 (μm)
It becomes.
[0063]
Based on the calculation result, a prepreg 301 having a thickness P0 of 120 μm before hot pressing is prepared. Then, the prepreg 301 having the thickness P0 before hot pressing and the core material 302 are laminated and integrated in this manner, so that a four-layer multilayer circuit board in which the interlayer thickness of each insulating base material 303 is uniform. Is obtained.
[0064]
Further, a method for manufacturing a multilayer circuit board having four or more layers using the multilayer circuit board having four layers obtained by the above method is the same as that described in the first embodiment. Also in the present embodiment, not only the thickness P0 before hot pressing set by equation (4) but also the thickness P0 ′ close to the thickness P0 set by equation (4) before hot pressing of the prepreg 301. May be set as the thickness. As a category of the approximation here, it is appropriate that the thickness is within ± 10% of the thickness P0 set by the equation (4).
[0065]
In the above-described embodiments, when fabricating a multi-layer circuit board having five or more layers, the pattern gaps of the wiring patterns of each layer may be of various sizes. In that case, the above-described formulas (2) to (4) are selected according to the combination of the pattern gaps of the wiring patterns facing each prepreg, and the selected formulas (2) to (4) are selected. ) May be used to calculate the thickness of each prepreg. By doing so, it is possible to obtain a multilayer circuit board in which the thickness between the respective layers (the thickness of the insulating base material) is uniformly controlled.
[0066]
(Embodiment 4)
The present embodiment is basically a method of manufacturing a multilayer circuit board similar to the above-described second embodiment. Therefore, in the following description, the same reference numerals are given to the respective parts as in the second embodiment. That is, 201 is a prepreg, 201a is an adhesive layer, 202 is a core material, 203 is an insulating base material, 204 is a metal foil, 205 is a wiring pattern, and 210 is a pattern gap. is there.
[0067]
In the present embodiment, the thickness of the prepreg 201 is set as follows.
[0068]
In the present embodiment, a wiring pattern 205A having a thickness Bt with a pattern remaining ratio of St is disposed opposite to one surface of the prepreg 201, and a wiring pattern 205B having a thickness Bb with a pattern remaining ratio of Sb is disposed on the other surface. Are arranged facing each other. Therefore, in the present embodiment, the thickness P0 of the prepreg 201 before hot pressing is set based on the following equation (5).
P0 = A / Cp + Bt (1-St) + Bb (1-Sb) (5)
P0: thickness of prepreg 201 before hot pressing
A: thickness of core material 202
Cp: hot press compression ratio of prepreg 201
Bt: thickness of the wiring pattern 205A
Bb: thickness of the wiring pattern 205B
St: Pattern remaining rate of the wiring pattern 205A
Sb: Pattern remaining rate of wiring pattern 205B
In the expression (5), the thickness of the prepreg 201 is set based on the following theory. As described in the first embodiment, the adhesive layer 201a enters the pattern gap 210 existing between the wiring patterns 205A and 205B adjacent to each other in the planar direction, and comes into close contact with the wiring patterns 205A and 205B. The prepreg 201 is apparently compressed by the penetration of the adhesive layer 201a into the pattern gap 210 as described above.
[0069]
The amount of compression of the prepreg 201 in the apparent compression depends on the pattern remaining rates St and Sb. That is, when the pattern remaining ratios St and Sb are close to 0%, the prepreg 201 is apparently compressed over a thickness corresponding to almost 100% of the thicknesses Bt and Bb of the wiring patterns 205A and 205B. On the other hand, when the pattern remaining rates St and Sb are close to 100%, the prepreg 201 is apparently hardly compressed.
[0070]
From this viewpoint, in the present embodiment, two parameters, ie, the pattern remaining ratios St and Sb and the thicknesses Bt and Bb of the wiring patterns 205A and 205B are further added to the above-described equations (2) to (4). The thickness P0 of the prepreg 201 before hot pressing is set on the basis of the above equation (5) to which is added.
[0071]
For example, the compression ratio Cp of the prepreg 201 is 98% (0.98), the thickness A of the base material 203 of the core material (double-sided substrate) 202 is 98 μm, and the wiring pattern 205A facing the one surface side of the prepreg 201 is formed. The thickness Bt is 20 μm, the pattern remaining ratio St is 50% (0.5), the thickness Bb of the wiring pattern 205B facing the other surface of the prepreg 201 is 18 μm, and the pattern remaining ratio Sb is 65% (0.65). If there is
P0 = A / Cp + Bt (1-St) + Bb (1-Sb)
= 98 / 0.98 + 20 × (1-0.5) + 18 × (1-0.65)
= 116.3 (μm)
It becomes.
[0072]
Based on the calculation result, a prepreg 201 having a thickness P0 of 116.3 μm before hot pressing is prepared. Then, the prepreg 201 having the thickness P0 set before the hot pressing and the core material 202 are laminated and integrated to form a four-layer multilayer circuit board in which the interlayer thickness of each insulating base material 203 is uniform. Is obtained.
[0073]
Further, a method for manufacturing a multilayer circuit board having four or more layers using the multilayer circuit board having four layers obtained by the above method is the same as that described in the first embodiment. Also in the present embodiment, not only the thickness P0 before hot pressing set by the equation (5) but also the thickness P0 ′ close to the thickness P0 set by the equation (5) before the hot pressing of the prepreg 201 is used. May be set as the thickness P0. As the category of the approximation here, a range of ± 10% of the thickness P set by the equation (5) is appropriate.
[0074]
(Embodiment 5)
In the present embodiment, in the manufacturing method of the above-described first to fourth embodiments, the ratio of the thickness of each wiring pattern (105, 205, 205A, 205B, 305) is added to the parameter, and the adhesive layer (101a, 201a, 301a) are set as follows.
[0075]
First, the pattern remaining ratio St of the wiring pattern (105, 205, 205A, 305) facing the adhesive layer (101a, 201a, 301a) on one side of the prepreg (101, 201, 301) and the other side, The pattern ratio (St / Sb) is calculated based on the pattern remaining ratio Sb of the wiring patterns (105, 205, 205B, 305) facing the adhesive layers (101a, 201a, 301a).
[0076]
Then, based on the calculated ratio (St / Sb), the thickness ht of the adhesive layer (101a, 201a, 301a) provided on one surface of the prepreg (101, 201, 301) and the adhesive layer ( 101a, 201a, and 301a) are set as follows.
[0077]
First, a thickness ratio (ht / hb) based on the thicknesses ht and hb is assumed. Then, the thicknesses ht, hb of the adhesive layers (101a, 201a, 301a) are changed so that the reciprocal 1 / (ht / hb) of the assumed thickness ratio (ht / hb) matches the pattern ratio (St / Sb). Set.
[0078]
More specifically, for example, the relative ratio of the pattern remaining ratio of the wiring patterns (105, 205, 205A, 205B, 305) that are arranged oppositely to both surfaces of the prepreg (101, 201, 301) is one surface side: the other surface side = In the case of 2: 1, the pattern ratio (St / Sb) is (2/1), and the reciprocal thereof is (1/2).
[0079]
In this case, each of the adhesives on both sides is so set that the thickness ratio (ht / hb) of the adhesive layer (101a, 201a, 301a) of the prepreg (101, 201, 301) is the same as the reciprocal (1/2). The relative ratio of the thickness of the layers (101a, 201a, 301a) is set.
[0080]
This makes it possible to obtain a multilayer circuit board in which the intervals between the layers (the thicknesses of the insulating bases 103, 203, and 303) are more uniformly controlled.
[0081]
Further, a method for manufacturing a multilayer circuit board having four or more layers using the multilayer circuit board having four layers obtained by the above method is the same as that described in the first embodiment. Also in the present embodiment, not only the thicknesses of the adhesive layers 101a, 201a, and 301a set by the above-described setting method, but also the thicknesses approximate to the thicknesses set by the above-described setting method. It may be set as the thickness of 201a and 301a. As a category of the approximation here, a value within ± 10% of a value set by the above setting method is appropriate.
[0082]
【The invention's effect】
As is apparent from the above description, according to the present invention, the thickness between the layers of the multilayer wiring board can be uniformly controlled, whereby the impedance matching between the wiring patterns of each layer can be easily achieved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a method for manufacturing a multilayer circuit board according to Embodiments 1 and 5 of the present invention.
FIG. 2 is an explanatory diagram of a method for manufacturing a multilayer circuit board according to Embodiments 2, 4, and 5 of the present invention.
FIG. 3 is an explanatory diagram of a method for manufacturing a multilayer circuit board according to Embodiments 3 and 5 of the present invention.
FIG. 4 is an explanatory diagram of a conventional method for manufacturing a multilayer circuit board.
[Explanation of symbols]
101, 201, 301 Pre-preg 101a, 201a, 301a Adhesive layer
102, 202, 302 Core material 103, 203, 303 Insulating base material
104, 204, 304 Metal foil 105, 205, 305 Wiring pattern
305A, 305B wiring pattern
106, 206, 306 Surface wiring pattern 110, 210 Pattern gap

Claims (8)

After providing a wiring pattern between the compressible insulating base material provided with an adhesive layer on its surface and the non-compressible insulating base material, the compressible insulating base material, the wiring pattern, and the incompressible insulating base A method of manufacturing a multilayer circuit board to produce a multilayer circuit board by heating and pressing the material,
A step of producing the compressible insulating base material whose thickness before heating and pressing is set according to the pattern remaining ratio of the wiring pattern,
A step of laminating the compressible insulating base material, the wiring pattern, and the non-compressible insulating base material, the thickness of which is set before the overheating and pressurizing by the above-mentioned process, and heating and pressing the same.
A method for manufacturing a multilayer circuit board, comprising: The method for manufacturing a multilayer circuit board according to claim 1,
When the pattern remaining ratio of the wiring pattern is low, reduce the thickness of the compressible insulating base material before heating and pressing,
A method for manufacturing a multilayer circuit board, comprising: The method for manufacturing a multilayer circuit board according to claim 1,
When the pattern remaining rate of the wiring pattern is high,
P0 = A / Cp
P0: Thickness of the compressible insulating base material before heating and pressing A: Thickness of the non-compressible insulating base material Cp: Heating of the compressible insulating base material according to a calculation formula of a compressibility by heating and pressing the compressible insulating base material Set the thickness before pressing,
A method for manufacturing a multilayer circuit board, comprising: The method for manufacturing a multilayer circuit board according to claim 1,
When the pattern remaining rate of the wiring pattern is low,
P0 = A / Cp + B
P0: Thickness of the compressible insulating base material before heating and pressing A: Thickness of incompressible insulating base material Cp: Compressibility of the compressible insulating base material by heating and pressing B: Compression by the calculation formula of wiring pattern thickness To set the thickness of the insulating insulating substrate before heating and pressing,
A method for manufacturing a multilayer circuit board, comprising: The method for manufacturing a multilayer circuit board according to claim 1,
Another wiring pattern having a low pattern remaining rate of the wiring pattern, and a low pattern remaining rate via an adhesive layer, on the surface of the compressible insulating base material not in contact with the incompressible base material, Or if metal foil is placed,
P0 = A / Cp + 2B
P0: thickness of compressible insulating base material before heating and pressing A: thickness of incompressible insulating base material Cp: compressibility of heating and pressing of compressible insulating base material B: thickness of wiring pattern and another wiring pattern Set the thickness of the compressible insulating base material before heating and pressurizing by the calculation formula,
A method for manufacturing a multilayer circuit board, comprising: The method for manufacturing a multilayer circuit board according to claim 1,
On the surface of the compressible insulating base material that the non-compressible base material is not in contact with, when another wiring pattern is arranged via an adhesive layer,
P0 = A / Cp + Bt (1-St) + Bb (1-Sb)
P0: Thickness of the compressible insulating base material before hot pressing A: Thickness of the non-compressible base material Cp: Hot press compressibility of the compressible base material Bt: Thickness of the wiring pattern Bb: Thickness of another wiring pattern St: Wiring pattern residual ratio Sb: The thickness of the compressible insulating base material before heating and pressing is set by an equation for calculating the pattern remaining ratio of another wiring pattern.
A method for manufacturing a multilayer circuit board, comprising: The method for manufacturing a multilayer circuit board according to claim 1,
On the surface of the compressible insulating base material that the non-compressible base material is not in contact with, when another wiring pattern is arranged via an adhesive layer,
The thickness of the two adhesive layers is such that the relative ratio of the thickness of the two adhesive layers matches the reciprocal of the relative ratio between the pattern remaining ratio of the wiring pattern and the pattern remaining ratio of the another wiring pattern. Set,
A method for manufacturing a multilayer circuit board, comprising: A multilayer circuit board manufactured by the method for manufacturing a multilayer circuit board according to claim 1.

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