KR20060046303A - Method for manufacturing multilayer printed circuit board and multilayer printed circuit board - Google Patents

Abstract

The present invention is a method of manufacturing a multilayer printed wiring board by IVH, which can produce a multilayer printed wiring board with high productivity by a simpler process, and does not cause a problem of warping during bonding, and thus a large interlayer adhesion strength. An object of the present invention is to provide a method for manufacturing a multilayer printed wiring board that can be obtained, and a multilayer printed wiring board manufactured by the manufacturing method. The solution means includes an insulating substrate, a conductive layer circuit formed on one surface thereof, And a one-side wiring board base material having an bump of the conductive material obtained by filling a via hole formed in the insulating substrate with an electrically conductive material and an adhesive sheet, and having a through hole having a diameter larger than that of the via hole at a position corresponding to the via hole. An adhesive sheet layer having a film, and another wiring board base material, so that the bumps are inserted into the through holes, Collectively these are the multilayered printed circuit board produced by the method, and a manufacturing method of the multilayered printed circuit board characterized in that the lamination press.

Description

Manufacturing method of multilayer printed wiring board and multilayer printed wiring board {METHOD FOR MANUFACTURING MULTILAYER PRINTED CIRCUIT BOARD AND MULTILAYER PRINTED CIRCUIT BOARD}

This invention relates to the manufacturing method of the multilayer printed wiring board which laminated | stacked the some printed wiring board, and the multilayer printed wiring board manufactured by the manufacturing method.

BACKGROUND ART A multilayer printed wiring board is known as a technique that enables high-density mounting of components and allows connections between components at the shortest distance (meaning electrical conduction, hereinafter simply referred to as connection). IVH (Interstitial Via Hole) is a technique applied to the manufacture of a multilayer printed wiring board which requires a higher density of mounting, and is characterized in that the adjacent layers are connected by filling a conductive material in an open hole between adjacent layers. According to IVH, the interlayer connection can be formed only in necessary portions, and parts can be mounted on the via holes, thereby enabling high-density wiring with high degree of freedom.

For example, Fujikura Technical Report No. 103, pages 49-51 (announced in October 2002), describes a multilayer printed wiring board produced by laminating a heat-resistant film represented by polyimide by IVH. 8 is a process chart showing a manufacturing process of this multilayer printed wiring board.

First, one side of a copper clad laminated plate 22 (Cupper Crad Laminate: CCL, FIG. 8A), wherein one side of the resin film 20 (insulating substrate) made of polyimide resin is covered with a copper clad layer 21. The copper coating layer 21 is etched to form a circuit (FIG. 8B). Next, after bonding the polyimide adhesive sheet layer 23 to the other surface (FIG. 8C), the hole-hole process is performed by a laser and the via hole 24 is formed (FIG. 8D). In this via hole, the wiring board base material 26 (FIG. 8E) obtained by filling the electrically conductive paste 25 by screen printing, and the copper clad laminated board 27 with a circuit are laminated | stacked and aligned (FIG. 8F), The multilayer printed wiring board 28 can be obtained by pressurizing with a cure press and performing interlayer adhesion (FIG. 8G).

In this method, after bonding the adhesive sheet layer 23 on the resin film 20, the via hole 24 is formed and screen printing is performed. Therefore, when bonding the resin film 20 and the adhesive sheet layer 23 to each other, it is necessary to adhere them, and therefore, it is necessary to heat above the glass transition point Tg of the adhesive sheet layer 23. have. That is, in this method, heating was required twice in the step of bonding the resin film 20 and the adhesive sheet layer 23 and in the step of interlayer adhesion.

In this method, when a thermoplastic resin having a low Tg is used for the adhesive sheet layer 23, after completion as a wiring board, it may be plasticized again by heating such as reflow and peeling may occur. On the other hand, when a thermoplastic resin having a high Tg is used, heating at the time of bonding the resin film 20 and the adhesive sheet layer 23 needs to be performed at a high temperature, thereby causing deterioration of the conductive paste 25. In addition, when a thermosetting resin-based adhesive agent is used, since a part of the adhesive is already cured in the pasting step, there is a problem that it is difficult to obtain sufficient interlayer bonding strength in the step of interlayer bonding.

In addition, in the copper cladding layer 21, the copper clad laminated board 22, and the adhesive sheet layer 23, since the elasticity modulus and thermal expansion coefficient are largely different, it is at the time of bonding the resin film 20 and the adhesive sheet layer 23 together. Curvature or stress deformation occurs. As a result, positional deviations tend to occur in the via hole forming step and the like, and there is a problem that the defective rate increases.

As a method for solving this problem, a thermoplastic polyimide sheet having a thermosetting function is used for the adhesive sheet layer, and when the sheet is bonded to the copper clad laminate, it is equal to or more than the Tg of the thermoplastic polyimide and is also a thermosetting component. A method of heating at a lower temperature than the curing start temperature Ts and heating at a higher temperature than Ts at the time of interlayer adhesion is disclosed in Japanese Patent Laid-Open No. 2004-95963 (claim 12). By this method, peeling by reflow etc. can be prevented and sufficient interlayer adhesion strength can be obtained. Moreover, in Unexamined-Japanese-Patent No. 2004-95963, in order to prevent the bending at the time of pasting, it is proposed to use the film which consists of resin whose Tg is 110 degrees C or less and the normal temperature elasticity modulus is 1300 MPa or less (paragraph 0035).

However, the method described in Japanese Patent Application Laid-Open No. 2004-95963 also requires two heating steps, namely, bonding and interlayer bonding, and the temperature must be changed, resulting in a complicated process and a cost increase. Becomes Moreover, since resin used is a specific kind and Tg and room temperature elastic modulus are limited to the thing of a specific range, the range of the selection is narrow.

Therefore, as a manufacturing method of the multilayer printed wiring board by IVH, development of the manufacturing method of the multilayer printed wiring board which solved the problem of the said prior art was desired.

[Patent Document 1]

Japanese Patent Laid-Open No. 2004-95963 (claim 12, paragraph 0035)

[Non-Patent Document 1]

Fujikura Technical Report No. 103, pages 49-51 (announced October 2002)

The present invention is a method of manufacturing a multilayer printed wiring board by IVH, which can produce a multilayer printed wiring board by a simpler step, and does not cause a problem of warping during bonding, and also obtains a large interlayer adhesion strength. It is a subject to provide the manufacturing method of the multilayer printed wiring board which exists, and the multilayer printed wiring board manufactured by the manufacturing method.

As a result of the investigation, the inventors have formed a via hole leading to the conductor circuit in the insulating substrate, and further has a wiring board base material having bumps of the conductive material formed in the via hole, and a position larger than the via hole at a position corresponding to the via hole. By stacking the adhesive sheet layer having a through hole and another wiring board base material and laminating and pressing them collectively, a multilayer printed wiring board can be manufactured by a simpler process, and it does not cause the problem of warping during bonding. Therefore, it was found that a large interlayer adhesion strength could also be obtained, and completed the present invention.

Aspect of this invention of Claim 1 is

One-sided wiring board having an insulating substrate, a conductive layer circuit formed on one surface thereof, and a via hole formed in the insulating substrate so as to reach the conductive layer circuit and open at the other surface thereof, the bump of the conductive material obtained by filling a conductive material. materials,

An adhesive sheet layer having a through hole having a diameter larger than that of the via hole at a position corresponding to the via hole;

At least three layers of another wiring board base material having a conductive layer circuit at a position corresponding to the via hole,

The adhesive sheet layer is sandwiched between the wiring board substrates, and the bumps are stacked so as to be inserted into the through holes, and they are collectively laminated and pressed.

The one side wiring board base material can be manufactured by forming a via hole, a bump, and a conductive layer circuit in an insulating substrate on which a conductive layer is attached to one surface. Here, as an insulating board | substrate with which the conductive layer was affixed on one surface, the copper foil adhesion polyimide resin base material (CCL) with which copper foil was affixed on one surface is illustrated.

The via hole (hole at the bottom) can be formed by performing a punching process using a laser or the like at a position where an interlayer connection of the insulating substrate is desired. The via hole penetrates through the insulating substrate, one end of which is opened on the surface opposite to the surface to which the conductive layer is attached, and the other end reaches the conductive layer. Moreover, you may form a hole with a small diameter also in conductive layers, such as copper foil. When the hole is formed, when the conductive material is filled into the via hole by screen printing, the hole functions as an air bleed hole for releasing air in the via hole, and the filling becomes easy.

After formation of the via hole, a conductive material is filled in the via hole, so that a bump is formed. Although the charging method of an electrically conductive material is not specifically limited, For example, the method of charging an electrically conductive material by screen printing is mentioned. Examples of the conductive material include silver paste, paste of copper filler or carbon mixture, solder cream, low melting point metal, and the like.

The bump of an electrically conductive material is a protrusion of the electrically conductive material formed on the via hole, and is formed in order to connect with the electrically conductive layer circuit of another wiring board base material. Although the method of forming the bump of an electrically conductive material is not specifically limited, For example, a release layer is formed on an insulating substrate, the via hole which penetrates this insulating substrate and a release layer is formed, and this via hole was filled with the electrically conductive material. Then, the method of peeling a mold release layer and forming a protrusion part is illustrated. As a mold release layer, the masking film of polyethylene terephthalate (PET), etc. are mentioned, These are stuck on an insulating substrate, and a mold release layer is formed. As another method of forming a bump of an electrically conductive material, the method of filling a via hole with an electrically conductive material, and also apply | coating electrically conductive paste etc. by screen printing on it further is mentioned.

The conductive layer circuit can be formed, for example, by etching the conductive layer. For example, after the circuit pattern of the resist layer is formed on the conductive layer, a chemical etching (wet etching) for immersing the conductive layer in an etching solution that corrodes, removing portions other than the circuit pattern, and then removing the resist layer is performed. Is illustrated. Examples of the etchant in this case include ferric chloride type etching solution containing ferric chloride as a main component, cupric chloride type etching solution and alkali etching solution. Usually, the circuit is formed before the formation of the via hole, but may be performed after the formation of the via hole or after the bump formation.

The adhesive sheet layer can be obtained by forming a through hole having a diameter larger than the diameter of the via hole in the adhesive sheet at a position corresponding to the via hole. The formation of the through hole at a position corresponding to the via hole means that when the one side wiring board base material and the adhesive sheet layer are stacked, the outlet of each via hole is included in the opening of the through hole, that is, the bump penetrates. It means forming a through hole so as to be inserted into the hole. The method for forming the through hole is not particularly limited, and a method of drilling through a laser, mechanically drilling using a drill, or the like can be adopted. As an adhesive sheet for forming an adhesive sheet layer, the thing of thickness of about 100 micrometers-about 100 micrometers is normally used, Preferably it is 15 micrometers-70 micrometers. If the thickness is less than 10 µm, the adhesive sheet layer is not sufficiently expanded during the lamination press of the interlayer adhesion, and the gap between the bump and the adhesive sheet is difficult to be eliminated. On the other hand, when it exceeds 100 micrometers, it becomes difficult to form the bump which has the length of the processus | protrusion corresponding to this thickness.

The adhesive sheet layer is stacked on the bump side of one side wiring board substrate having the above bumps, and is further stacked on top of another wiring board substrate having a conductive layer circuit at a position corresponding to the via hole. By pressing, a multilayer printed wiring board is produced. That is, one side wiring board base material which bump was formed, and another wiring board base material which has a conductive layer circuit are adhere | attached by the adhesive sheet layer interposed between them, and a multilayer printed wiring board is manufactured. The other wiring board base material which has a conductive layer circuit is an wiring board base material which has an insulating substrate and the conductive layer circuit formed on the one surface or both surfaces, and a part of this conductive layer circuit is formed in the position corresponding to the said bump.

Another wiring board base material can be manufactured by etching, for example, copper foil of the polyimide resin film by which copper foil was affixed on one side or both surfaces, and forming a circuit. In addition, as will be described later, another wiring board base material has an insulating substrate and conductive layer circuits formed on both surfaces thereof, and the conductive layer circuits on both surfaces are connected to each other by a conductive material filled in a through hole. A wiring board base material can also be illustrated.

In the multilayer printed wiring board of the present invention, the adhesive sheet layer is sandwiched between the wiring board substrate and at least three layers of the one side wiring board substrate, the adhesive sheet layer, and the other wiring board substrate, and the bumps are formed in the through holes. They are stacked so as to be inserted, and they are manufactured by laminating | stacking them collectively. That is, since the multilayer printed wiring board of this invention can be manufactured by one lamination press, high productivity can be obtained.

The lamination press can be performed by heating and pressurizing with a cure press or the like. Since the diameter of the through-hole formed in the adhesive sheet layer is larger than the diameter of the via hole, there is a gap between the adhesive sheet layer and the bump before the lamination press starts, but the adhesive sheet layer is applied to the conductive material of the bump by the lamination press. This gap is eliminated by expanding until contact. In the case where the bumps undergo plastic deformation, the bumps are also deformed by the lamination press, so that the gap may be eliminated. In this way, the wiring board base material with bumps and another insulating substrate having a conductive layer circuit are firmly bonded by the adhesive sheet layer.

When laminating one side wiring board base material, an adhesive sheet layer, and another wiring board base material, it is preferable to carry out temporary adhesion which is simple adhesion, in order to prevent the shift | offset | difference during lamination | stacking or a lamination | pressing press, but temporary attachment is a paste in the prior art. In comparison, it is carried out in much milder conditions. For example, in the case of an epoxy adhesive, a heating time of about 10 to 60 seconds is sufficient at a temperature of about 120 to 140 ° C, and in the case of a polyimide adhesive, it is 10 to a temperature of about 170 to 200 ° C. A heating time of around 60 seconds is sufficient. As a result, the number of times of heating decreases compared with said conventional method, and a multilayer printed wiring board can be manufactured by a simpler process. Moreover, the warpage does not occur due to the heating at the time of joining, which has been a problem of the above prior art. In addition, even when a thermosetting resin is used as the adhesive, since it is not heated and partially cured in the bonding step, a large adhesive strength can be obtained at the time of interlayer adhesion.

The manufacturing method of the multilayer printed wiring board of this invention is applicable also when there are many said one side wiring board base materials, an adhesive sheet layer, etc. In this case, the said adhesive sheet layer and the said wiring board base material are laminated | stacked alternately, these are collectively press-laminated. Here, a wiring board base material is a meaning including both the said one side wiring board base material and the said other wiring board base material. That is, the said adhesive sheet layer is sandwiched so that the said bump may be inserted in the said through hole between the said one side wiring board base material, or between the said one side wiring board base material, and the said other wiring board base material, and a laminated press is performed collectively. Claim 2 corresponds to this aspect.

According to the manufacturing method of this invention, adhesion by heating is only once of a lamination | stacking press, and it does not need to perform the bonding by heating for every formation of each wiring board base material like the conventional method. Therefore, the manufacturing process can be greatly simplified, and warping or the like does not occur, so that problems such as misalignment do not occur.

As said another wiring board base material, the double-sided wiring board base material which has an electrically conductive layer circuit on the insulating substrate and its both surfaces, and is connected between the conductive layer circuits on both surfaces by the electrically conductive material filled in the through-hole which penetrates the said insulating substrate. Can be used. Claim 3 corresponds to this aspect.

Such a double-sided wiring board base material is, for example, a step of etching a copper foil of a polyimide resin film coated with copper foil on both surfaces to form a circuit, and copper foil (conductive layer) on both surfaces, and It can manufacture by the method which has a process which forms the through-hole which penetrates a polyimide resin film (insulating board | substrate), fills this through-hole, and connects copper foil of both surfaces. Either one may be sufficient as the process of forming a circuit and the process of the connection between copper foil. In addition, formation of a circuit, formation of a through hole, and filling of an electrically conductive material can be performed similarly to the above.

When the said other wiring board base material is a single-sided wiring board base material, and is a double-sided wiring board base material which is not connected between the conductive layer circuits on both surfaces, this other wiring board base material is piled up on the uppermost adhesive sheet layer, and collectively Lamination is pressed. The uppermost adhesive sheet layer means a layer closest to the outer side among the adhesive sheet layers used for the adhesion between the multilayers in which circuits are connected to each other.

When the said other wiring board base material is a double-sided wiring board base material with which between the conductive layer circuits on both surfaces are connected, this other wiring board base material may be piled up on the adhesive agent layer of the upper part, and may be piled on the adhesive sheet layer other than the uppermost. do. Another adhesive sheet layer is superimposed on the double-sided wiring board substrate superimposed on the adhesive sheet layer other than the uppermost one, and the one side wiring board substrate is superimposed so that the bumps are inserted into the through-holes of the other adhesive sheet layer. Furthermore, the overlap of the adhesive sheet layer and the said one side wiring board base material is repeated, and these are collectively pressed by lamination | stacking after that.

The diameter of the through hole of the adhesive sheet layer is preferably 1.5 to 5 times the diameter of the via hole of the wiring board substrate, that is, the diameter of the bump, and more preferably 3 to 5 times. If it is less than 1.5 times, the alignment at the time of lapping | stacking an adhesive sheet layer and a wiring board base material will not become easy, and it will be easy to produce a bump which will not insert in the through-hole of an adhesive sheet layer. On the other hand, when it is 5 times or more, it becomes difficult to expand until an adhesive sheet layer contacts a bump at the time of a laminated press, and there exists a possibility that the space | interval between both may not be eliminated. Claim 4 corresponds to this preferable aspect.

As a material which forms the conductive layer circuit of the said one side wiring board base material and the other wiring board base material, the material which mainly uses copper is used normally. Claim 5 provides the manufacturing method of the multilayer printed wiring board which concerns on this aspect. As a material mainly containing copper, the alloy which has copper or copper as a main component is illustrated. As the material of the conductive layer circuit, in addition to copper, a silver paste, a copper plated copper paste, or the like is used.

As an insulating board which comprises the said one side wiring board base material, the resin film which mainly uses PET and polyimide is illustrated. A resin film mainly composed of polyimide is a heat resistant film, and may be subject to the demand for high heat resistance corresponding to the adoption of solder containing no lead. Moreover, the loss in high frequency transmission is small compared with resin contained in ceramic and glass fabric, and thickness reduction and high strength of an insulating substrate can be achieved. Claim 6 corresponds to this preferable aspect. Moreover, also about the insulating board which comprises the said other wiring board base material, the resin film mainly containing polyimide is illustrated preferably.

Examples of the material (adhesive) of the adhesive sheet for forming the adhesive sheet layer include thermoplastic polyimide resins, thermoplastic polyimide resins mainly having thermosetting functions, and thermosetting resins such as epoxy resins and imide resins. Claim 7 corresponds to this aspect. Among the above examples, a resin, a thermosetting epoxy resin, and a thermosetting imide-based resin having a thermosetting function mainly as the thermoplastic polyimide mainly is preferable since sufficient adhesive strength is secured after heat curing.

In the case of using an adhesive sheet formed mainly of a thermosetting epoxy resin, since they have low water absorption, the resistance (contact resistance between the conductive material filled in the empty hole and the conductive layer) does not increase most after exposure to a high temperature, high humidity atmosphere. . Therefore, after being completed as a multilayer printed wiring board, it is exposed to a high temperature, high humidity atmosphere, and the resistance of the entire circuit is not raised to significantly affect the function of the multilayer printed wiring board. From this point of view, the adhesive mainly comprising a thermosetting epoxy resin It is preferable to use a sheet. Claim 8 corresponds to this more preferable aspect.

In addition, the adhesive sheet which forms an adhesive sheet layer may laminate | stack two or more types of resin layers. For example, the adhesive sheet which consists of three layers which laminated | stacked the high Tg (200 degreeC or more) hardening | curing agent polyimide resin used for copper clad laminated board etc. to thermosetting epoxy resin, and further laminated | stacked the thermosetting epoxy resin on it is illustrated. .

Moreover, since the stress at the time of a reflow test becomes small when the vertical elastic modulus of an adhesive sheet is 3 GPa or less, it is advantageous. On the other hand, when the vertical elastic modulus is less than 0.001 GPa, the growth may be too large and handling may be difficult. Therefore, from this viewpoint, it is preferable to use the adhesive sheet whose longitudinal modulus (Young's modulus) is 0.001 GPa or more and 3 GPa or less. Claim 9 corresponds to this preferred embodiment.

In addition, in order to facilitate the mounting of parts, it is desired that the multilayer printed wiring board be flat, but using an adhesive sheet having a small elastic modulus causes a large deformation such as warpage during pressing, resulting in the occurrence of concave portions in the multilayer printed wiring board. . Therefore, an adhesive sheet which does not cause this problem is desired, and this request is particularly strong for the outermost adhesive sheet close to the mounting portion of the part. In this respect, an adhesive sheet made of a material having high rigidity and difficult to deform and having a high elastic modulus is preferably used.

On the other hand, however, the adhesive sheet formed of a single member of a material having high rigidity has a problem that the growth is small and the thermal stress is weak. This problem can be solved by a composite material combining a high rigidity material with a flexible adhesive. Claim 10 and Claim 11 correspond to the form using the adhesive sheet formed by this composite material, and it is easy to form a flat multilayer printed wiring board, and also provides the preferable aspect which solved the problem that the growth was small and weak against thermal stress. will be.

That is, Claim 10 is a manufacturing method of said multilayer printed wiring board, Comprising: The adhesive sheet is a sheet | seat formed by impregnating an adhesive agent with a highly rigid porous material, It is providing the manufacturing method of the multilayer printed wiring board, Claim 11 Silver is a manufacturing method of the said multilayer printed wiring board, The adhesive sheet is a sheet | seat formed by sandwiching a highly rigid insulating film layer between two adhesive layers, It is providing the manufacturing method of the multilayer printed wiring board.

Also in this case, the adhesive agent same as the above can be used as an adhesive agent. As a porous material having high rigidity, a material having an elastic modulus of 50 GPa to 200 GPa is preferable. Specifically, what consists of fiber, glass fiber, etc. which have rigidity, such as aramid, for example, nonwoven fabric is mentioned. Although it does not specifically limit as a method of impregnation, For example, after melt | dissolving an adhesive in a solvent and making it impregnate, the method of evaporating and removing a solvent is mentioned.

The highly rigid insulating film layer is insulating and preferably a film made of a material having an elastic modulus of 5 GPa to 10 GPa. Specifically, the polyimide film marketed by brand names, such as UPILEX 25S (made by Ube Industries), is mentioned, for example.

The present invention also provides a multilayer printed wiring board, which is produced by the above method for producing a multilayer printed wiring board (claim 12). The multilayer printed wiring board of this invention is a wiring board which can mount the component of high density, and is used for manufacture of various electrical products.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Next, the best form for implementing this invention is demonstrated using drawing. In addition, this invention is not limited to this form, A change to other forms is also possible, unless the meaning of this invention is impaired.

1 is a process chart showing an example of a manufacturing process of one side wiring board base material used for forming a multilayer printed wiring board. One side copper clad laminated board 3 forming copper cladding layer 2 (copper foil, conductive layer) having a thickness of 12.5 μm on one side of polyimide resin sheet 1 (insulating substrate) having a thickness of 25 μm ( Using CCL and FIG. 1A), the copper coating layer 2 is masked and wet etched to form a circuit pattern on the copper coating layer 2 (FIG. 1B).

Next, a release layer 4 having a thickness of 50 µm made of PET was attached to the surface of the polyimide resin sheet 1 opposite to the surface on which the copper clad layer 2 was formed (FIG. 1C). By laser processing, via holes 5 (bottom holes, blind vias) having a diameter of 100 µm are formed at predetermined positions at 1 to 8 positions (FIG. 1D). Although the UV-YAG laser was used for laser processing of this example, it is not limited to this, Another laser can also be used, and via holes can also be formed by methods other than laser processing.

Next, after the desmear process which removes smears, such as resin of copper hole and oxide of copper foil which remain | survives in the via hole 5, is performed and the inside of the via hole 5 is cleaned, A conductive material made of silver paste is filled by filling a hole in the via hole 5 by squeezing from the surface side of the release layer 4 by using a squeegee plate used for screen printing. 6) (FIG. 1E). Thereafter, by removing the release layer 4, the bumps 7 of the conductive material having the projections of 40 μm are formed (FIG. 1F) to obtain one side wiring board base material A. In addition, even if the above release layer 4 is not pasted, the bumps 7 can be formed by filling the via holes 5 by filling them with holes, followed by drying, bump printing and drying. .

2 is a process chart showing an example of a manufacturing process of the adhesive sheet layer used in the method for producing a multilayer printed wiring board of the present invention. An adhesive sheet layer is opened using a drill at a position corresponding to the bump 7 of the wiring board base material A of the adhesive sheet 11 (FIG. 2A) having a thickness of 25 μm using a drill. Obtain B (FIG. 2B). In addition, when the thickness of an adhesive sheet is about 100 micrometers or less, it is also possible to use a laser instead of a drill for formation of such a through hole.

FIG. 3 is a process diagram showing a manufacturing process of another wiring board substrate laminated with the one side wiring board substrate A and the adhesive sheet layer B. FIG. In this example, a double-sided copper clad laminate (CCL) forming a copper cladding layer 13 (copper foil, conductive layer) having a thickness of 12.5 μm on both sides of a polyimide resin sheet 14 (insulating substrate) having a thickness of 25 μm is formed. (FIG. 3A). The double-sided wiring board base material C in which the circuit which consists of a copper-coated layer 13 was formed in both surfaces of the polyimide resin sheet 14 by masking both surfaces of the copper-coated layer 13 and wet-etching, respectively (FIG. 3B). For example, it is also possible to obtain and use the one side wiring board base material which formed the circuit only in one side using the one side copper clad laminated board instead of the double-side copper clad laminated board.

FIG. 4 is a process diagram showing a step of stacking the one side wiring board base material A, the adhesive sheet layer B, and the double-sided wiring board base material C obtained as described above to manufacture the multilayer printed wiring board of the present invention. First, the bump 7 of the one side wiring board base material A (via hole), the through-hole 12 of the adhesive sheet layer B, and the copper cladding layer 13 (copper land) which formed the circuit of the double-sided wiring board base material C are each, respectively. In order to be in series at the position, the hole for positioning is superimposed through the positioning pin, and a temporary attachment is performed within a temperature range in which the adhesive does not completely cure (FIG. 4A). The hole for positioning (not shown) is opened in one side wiring board base material A, adhesive sheet layer B, and double-sided wiring board base material C by laser processing etc. before lamination | stacking.

Then, it heats and pressurizes at 180-220 degreeC and 10-40Kg / cm <2> by the machine similar to a vacuum press machine or a vacuum press machine. Since the through-hole 12 of the adhesive sheet layer B is larger than the diameter (empty hole diameter) of the bump 7, in the initial stage of pressing, the adhesive sheet 11 and the bump 7 do not come into contact with each other. Both the sheet 11 and the conductive material forming the bump 7 flow, and the adhesive sheet 11 and the bump 7 come into contact with each other to form the multilayer printed wiring board 15 of the present invention (FIG. 4B). Since the pressurization continues while cooling after completion | finish of heating, curvature etc. do not arise.

Although the example of FIG. 4 is an example which manufactures the multilayer printed wiring board of this invention by bonding one side wiring board base material of one layer, and another wiring board base material using an adhesive sheet layer, the manufacturing method of the multilayer printed wiring board of this invention is It is also applicable to the case where one side wiring board base material of two or more layers is used. FIG. 5: is a process drawing which shows the process of manufacturing the multilayer printed wiring board of this invention using the one side wiring board base material of two layers.

Both sides manufactured in the same manner as the one side wiring board base material A1, A2 manufactured in the same manner as the one side wiring board base material A, the adhesive sheet layer Bl, B2, and the double sided wiring board base material C produced in the same manner. Multilayer printing of this invention by laminating | stacking wiring board base material C 'as shown to FIG. 5A, and pressurizing and heating collectively by the machine according to the vacuum press machine or the vacuum press machine similarly to the case of the example of FIG. The wiring board 16 is formed (FIG. 5B).

FIG. 6 is a process diagram showing a step of manufacturing a multilayer printed wiring board of the present invention using a two-layered single-sided wiring board substrate similar to the example of FIG. 5, but is a double-sided wiring board substrate C 'in the case of the example of FIG. 5. Instead, the example using C "which is a double-sided wiring board base material connected between the conductive layer circuits (copper coating layer) on both surfaces by the electrically conductive material filled in the via hole which penetrates an insulating substrate is shown. Instead of C '. A multilayer printed wiring board 17 of the present invention is formed in the same manner as in the example of FIG. 5 except that C ″ is used (FIG. 6B).

FIG. 7 is a process diagram showing a step of manufacturing a multilayer printed wiring board of the present invention using a double-sided wiring board substrate, wherein the one-side wiring board substrate of three layers and the conductive layer circuits on both surfaces are connected, but FIG. Unlike the example, the double-sided wiring board base material C "is used for the inner side of the cross section. In order of the single-sided wiring board base material A1, the adhesive sheet layer B1, the one side wiring board base material A2, the adhesive sheet layer B2, and the double-sided wiring board base material C". The same as in the example of FIG. Then, the adhesive sheet layer B3 and one side wiring board base material A3 are piled up on double-sided wiring board base material C "so that the bump of A3 may be inserted into the through hole of B3, and these are collectively collectively, in the case of the example of FIGS. 4-6 mentioned above. Similarly, the multilayer printed wiring board 18 of this invention is formed by pressurizing and heating by the machine similar to a vacuum press machine or a vacuum press machine (FIG. 7B).

Test Example

10 cm sample prepared by the steps shown in FIGS. 1A and B (without bonding of the adhesive sheet layer) and 10 cm sample prepared by the steps shown in FIGS. 8A, b and c (adhesive sheet layer Dimensional change rate (10-point average) after pressing at 180 degreeC, 30Kg / cm <2>, and 30 minutes conditions was measured, and the state of curvature was visually determined.

The dimensional change rate of the sample without adhesion of an adhesive sheet layer was 0.01%, and curvature was not seen. On the other hand, the dimensional change rate of the sample with the adhesion of the adhesive sheet layer was 0.12%, and curvature was seen. This result indicates that when there is no bonding of an adhesive sheet layer, a dimensional change is small and there is no curvature and it is excellent.

<Example>

As a conductive material made of silver paste, epoxy paste resin (55% by volume of scale silver having an average particle diameter of 2.6 µm was added to a mixture of 70 parts by weight of bisphenol A and 30 parts by weight of bisphenol F). And latent hardener), and the same as in the above-described embodiment shown in Figs. 1 to 4, except that those shown in Table 1 are used as the adhesive sheet (but the release layer 4). Was not carried out, and the number of the via holes 5 was 8 and the diameter of the through holes 12 was 300 µm) to create a multilayer printed wiring board. About the obtained multilayer printed wiring board, the result of having measured the reflow excellent product rate and the reliability (resistance change after high temperature, high humidity standing) after reflow is shown in Table 1. In addition, the result of having measured the longitudinal elastic modulus (Young's modulus) of an adhesive sheet is also shown in Table 1.

In addition, each evaluation value was measured and evaluated as follows.

Reflow excellent product rate: The multilayer printed wiring board was heated at 300 degreeC in total heating time for 5 second at the temperature of 260 degreeC at the time of peak, and the ratio of the multilayer printed wiring board whose resistance change is less than 10% was calculated | required.

Reliability after reflow (resistance change after high temperature, high humidity): The range of resistance change rate (%) after holding for 1000 hours in an atmosphere of 85 ° C. and 85% humidity was obtained. Here, the resistance value is a value measured by the four-terminal method of the resistance value of the circuit combined with the silver paste filled in eight via holes, and the resistance of a silver paste, the resistance of a conductive layer (circuit), and a silver paste and a conductive It is assumed to be the sum of the contact resistances of the layers. In addition, using a multilayer printed wiring board having a resistance change of 20% or less as a good product, the range of the resistance change rate and the ratio of the good product are shown in Table 1.

Longitudinal elastic modulus (Young's modulus): Based on IPC-TM-650 2. 4. 19, Tenshiron method, it measured at the tensile velocity of 50 mm / min.

Resin of adhesive sheet Longitudinal modulus of elasticity: room temperature GPa Reflow excellent article rate (the number of the quality goods / the number of tests) Reliability after reflow: Range of resistance change rate (good quality / test number) Espenex SPB-035A ^{* 1} Thermoplastic Polyimide Resin 1.66 100% (12/12) 10 to 100% (4/12) TLF-Y ^{* 2} Thermosetting Epoxy Resin 0.033 100% (12/12) 0-10% (12/12) TLF-B ^{* 3} Thermosetting Imide Resin 1.7 100% (12/12) 0 to 150% (1/12) GX ^{* 4} - 3.5 50% (6/12) 0 to 100% (1/6)

* 1: Thermoplastic polyimide bonding sheet manufactured by Shin-Etsu Chemical Co., Ltd.

* 2: Tomogawa Paper Co., Ltd. thermosetting epoxy bonding sheet (low elastic high adhesive film)

* 3: Tomoegawa Paper Co., Ltd. thermosetting imide bonding sheet (high heat resistant adhesive film)

* 4: AJINOMOTO-FINE-TECHNO Bonding Sheet

Moreover, although the following evaluation was also performed about the reliability after the reflow of the said multilayer printed wiring board, all 100% of excellent quality products are obtained.

Heat cycle: The multilayer printed wiring board with a resistance change of less than 10% after repeating 1000 cycles which hold | maintained 30 minutes at -40 degreeC, and temperature-rise and hold | maintained at 125 degreeC for 30 minutes was made into a superior product.

High temperature standing: The multilayer printed wiring board with a resistance change within 10% after leaving 1000 hours at 85 degreeC was made into the top quality.

Low temperature: A multilayer printed wiring board having a resistance change of less than 10% after being left for 1000 hours at −40 ° C. was used as a good product.

Movement after high temperature, high humidity standing: The multilayer printed wiring board with a resistance of 10 ⁸ ohms or more after 1000 hours standing at 85 degreeC and 85% of humidity was made into the top quality.

As a result of the above test example, in the multilayer printed wiring board of the present invention, it is clear that the problem of warping does not cause during bonding of the manufacturing process. Moreover, although the multilayer printed wiring board of this invention has a big interlayer adhesive strength, as is clear from the result shown in Table 1, etc., it also has the outstanding reflow quality part and the reliability after reflow. Particularly, even when a thermosetting epoxy resin is used as the adhesive sheet, excellent reflow superior product rate and reliability after reflow are obtained, which are equivalent to those when using a thermoplastic polyimide resin or a thermosetting polyimide resin. It is clear from the results.

Moreover, especially when the adhesive sheet which consists of Espenex SPB-035A, TLF-Y, and TLF-B whose vertical elastic modulus exists in the range of 0.001 GPa or more and 3 GPa or less is used, the outstanding reflow-quality ratio is especially obtained. have. Moreover, especially when the adhesive sheet which consists of TLF-Y of a thermosetting epoxy resin is used, the outstanding reliability after reflow is acquired.

According to the manufacturing method of the multilayer printed wiring board by IVH of this invention, since the multilayer printed wiring board which consists of several wiring board base materials can be manufactured by one lamination | stacking press, compared with the conventional manufacturing method by IVH, in a simple process As a result, a multilayer printed wiring board can be manufactured with high productivity. In addition, it is possible to obtain a large interlayer adhesion strength without causing problems such as warping when the insulating substrate on which the conductive layer is formed and the adhesive sheet layer are bonded together. In particular, even when manufacturing a multilayer printed wiring board made up of a plurality of wiring board substrates, such as stacking two or more of the one side wiring board substrates, the heating lamination step is performed in one circuit. The improvement effect is big.

1 is a process chart showing one step of an example of the manufacturing method of the present invention.

2 is a process chart showing one step of an example of the manufacturing method of the present invention.

3 is a process chart showing one step of an example of the manufacturing method of the present invention;

4 is a flowchart showing one step of an example of the manufacturing method of the present invention.

5 is a flowchart showing one step of another example of the manufacturing method of the present invention.

6 is a process chart showing one step of another example of the manufacturing method of the present invention.

7 is a process chart showing one step of another example of the manufacturing method of the present invention.

8 is a process diagram showing a step in the conventional method for manufacturing a multilayer printed wiring board.

<Description of Symbols for Main Parts of Drawings>

1, 14: polyimide resin sheet 2, 13, 21: copper clad layer

3, 22: copper clad laminate 4: release layer

5, 24: Beer Hall 6: Challenger Part

7: bump 11: adhesive sheet

12: through hole 20: resin film

25: conductive paste 27: copper clad laminate

26, A, A1, A2, A3: one side wiring board substrate

23, B, B1, B2, B3: adhesive sheet layer C, C ', C ": double-sided wiring board base material

15, 16, 17, 18, 28: multilayer printed wiring board

Claims (12)

One-sided wiring board having an insulating substrate, a conductive layer circuit formed on one surface thereof, and a via hole formed in the insulating substrate so as to reach the conductive layer circuit and open at the other surface thereof, the bump of the conductive material obtained by filling a conductive material. materials, An adhesive sheet layer having a through hole having a diameter larger than that of the via hole at a position corresponding to the via hole; At least three layers of another wiring board base material having a conductive layer circuit at a position corresponding to the via hole, The adhesive sheet layer is sandwiched between the wiring board substrates, and the bumps are stacked so as to be inserted into the through-holes, and these are collectively laminated and pressed. The method of claim 1, Two or more of the one side wiring board substrate, two or more of the adhesive sheet layer, and the other wiring board substrate are alternately stacked so that the adhesive sheet layer is sandwiched between the wiring board substrate and the bump is inserted into the through hole, Laminated | multilayer press of these are carried out collectively, The manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. The method according to claim 1 or 2, The said other wiring board base material has a conductive layer circuit on an insulating board and its both surfaces, and is connected between the conductive layer circuits on both surfaces by the electrically conductive material filled in the through-hole which penetrates the said insulating board. The manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. The method according to any one of claims 1 to 3, The diameter of the through-hole of an adhesive bond sheet layer is 1.5-5 times the diameter of the via hole of one side wiring board base material, The manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. The method according to any one of claims 1 to 4, A conductive layer circuit is made of a material mainly composed of copper. The method according to any one of claims 1 to 5, The insulating substrate is a resin film mainly containing polyimide, The manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. The method according to any one of claims 1 to 6, An adhesive sheet mainly comprises a thermoplastic polyimide resin, a thermosetting epoxy resin or a thermosetting imide resin, and the manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. The method of claim 7, wherein An adhesive sheet mainly comprises a thermosetting epoxy resin, The manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. The method according to claim 7 or 8, The longitudinal elastic modulus of an adhesive sheet is 0.001 GPa or more and 3 GPa or less, The manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. The method according to any one of claims 1 to 9, An adhesive sheet is a sheet | seat formed by impregnating an adhesive agent with a highly rigid porous material, The manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. The method according to any one of claims 1 to 9, An adhesive sheet is a sheet | seat formed by sandwiching a highly rigid insulating film layer between two adhesive layers, The manufacturing method of the multilayer printed wiring board characterized by the above-mentioned. It is manufactured by the manufacturing method of the multilayer printed wiring board in any one of Claims 1-11, The multilayer printed wiring board characterized by the above-mentioned.