JP2004080027A - One-side multilayer wiring board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-side multilayer wiring board in which a build-up layer having an insulating layer and a wiring layer is only formed on one main surface of a core substrate and which can be reduced in warping, and to provide a method by which the wiring board can be manufactured appropriately. <P>SOLUTION: In the one-side multilayer wiring board 1 in which the build-up layer having the insulating layer 4 and wiring layer 5 is only formed on one main surface of the core substrate 2, the insulating layer 4 is formed by using a film-like insulating resin material and, at the same time, the content of a solvent component contained in the insulating resin material is adjusted to ≤4 wt%. <P>COPYRIGHT: (C)2004,JPO

Description

{Circle over (1)} The present invention relates to a single-area wiring board and a method of manufacturing the same, and more particularly, to a single-area wiring board capable of reducing warpage and a manufacturing method suitable for manufacturing the same.

ビ ル ド There is a build-up method as a method of manufacturing a multilayer printed wiring board. This is achieved by laminating and forming an insulating layer on a core substrate using an interlayer insulating film made of an insulating resin material, and forming a wiring layer thereon. In addition, the interlayer insulating film made of an insulating resin material becomes a predetermined insulator layer by being subjected to a curing treatment after being formed on the core substrate. That is, by using the build-up method, a build-up layer having an insulator layer and a wiring layer is formed on the core substrate. In recent years, a method of forming a build-up layer by laminating an interlayer insulating film made of an insulating resin material on a core substrate to form a build-up layer has attracted attention as a technique for simplifying a manufacturing process.

{Circle around (2)} In the build-up layer, wiring patterns forming two wiring layers separated by an insulator layer are electrically connected by an interlayer conductor called a via. This via is formed by plating a conductor in a via hole formed in the insulator layer. Two methods are mainly used to form this via hole. One is to add a photosensitive resin component to the interlayer insulator film to impart photosensitivity to the insulator layer, and irradiate the insulator layer with ultraviolet rays through a mask to expose and develop the via hole pattern at a predetermined position. Is formed. The other is to form a pattern of a via hole at a predetermined position of an insulator layer using a laser without positively including a photosensitive resin component in an interlayer insulator film.

Although the build-up layer has the form described above, the multilayer printed wiring board on which the build-up layer is formed has a single-area layer wiring in which the build-up layer is formed only on one main surface of the core substrate. There are a substrate and a double-sided laminated wiring substrate in which build-up layers are formed on both main surfaces of a core substrate. These single-area wiring boards and double-sided laminated wiring boards are manufactured so as to take one of the forms depending on the intended use. In particular, in order to meet the demand for cost reduction of a multilayer printed wiring board, various functions have been designed to be provided by a single area layered wiring board. As a patent document relating to a single-area wiring board, there is, for example, JP-A-2002-290031.

JP-A-2002-290031 (FIG. 1 etc.)

However, when the build-up layer is formed only on one main surface of the core substrate, excessive warpage occurs in the core substrate in the process of laminating and forming the insulator layer and the wiring layer that constitute the build-up layer. For example, there are problems such as deterioration of alignment accuracy when forming a via hole pattern at a predetermined position of an insulator layer, and an increase in misalignment when sequentially forming an insulator layer and a wiring layer. This, as a result, hinders the production of a single-layer wiring board as a desired one and makes it non-defective, and causes a reduction in product yield. Also, if the amount of warpage of the core substrate increases, it also affects the displacement and the like when mounting electronic components and the like on the manufactured single-area wiring board, so controlling the amount of warpage of the core substrate is difficult. In the case of a single-area wiring board, this is an unavoidable problem.

As described above, when the build-up layer is formed on one main surface of the core substrate, it is important to control the amount of warpage of the core substrate, that is, the amount of warpage of the one-layer wiring board. Indeed, the present invention has been made in view of such a problem, that is, the present invention provides a one-area layer wiring board capable of reducing warpage and a manufacturing method suitable for manufacturing the same. Aim.

In order to solve the above problems, a method for manufacturing a single area layer wiring board according to the present invention includes:
Only one main surface of the core substrate, a method for manufacturing a single-area layer wiring board to form a build-up layer having an insulator layer and a wiring layer,
The insulator layer is formed by coating a film-shaped insulating resin material on one main surface of the core substrate and performing a curing process;
In addition, in order to suppress the warpage generated in the one-area layer substrate due to the heat shrinkage of the insulating resin material in the curing treatment, the content of the solvent component contained in the insulating resin material is set to 4% by weight or less. It is characterized by the following.

In addition, the one-area layer wiring board of the present invention for solving the above problems,
Only one main surface of the core substrate, a single-area layer wiring board in which a build-up layer having an insulator layer and a wiring layer is formed,
The insulator layer is formed by coating a film-shaped insulating resin material on one main surface of the core substrate and performing a curing process,
In addition, in order to suppress warpage generated in the one-layer substrate due to heat shrinkage of the insulating resin material in the curing treatment, the content of the solvent component contained in the insulating resin material is set to 4% by weight or less. It is characterized by becoming.

The present invention is directed to a single-area wiring board in which a build-up layer having an insulating layer and a wiring layer is formed only on one main surface of a core board. Further, the purpose of the present invention is to control the amount of warpage generated in the one-layer wiring board. The present inventor has repeatedly conducted various experiments and studies, and as a result of intensive studies, found that the composition of a film-shaped insulating resin material (hereinafter, also referred to as a resin film) used when forming an insulating layer as a build-up layer is formed. It has been found that there is a very close dependence on the amount of warpage generated in the one-layer wiring board. The resin film contains many components such as a resin component, a curing agent component, a filler component, and a solvent component in a predetermined ratio. Specifically, the content of the solvent component is a problem. I understood. Therefore, in the present invention, the content of the solvent component contained in the resin film used when forming the insulating layer by lamination is set to 4% by weight or less. By optimizing the solvent component contained in the resin film in this manner, it is possible to effectively suppress the amount of warpage generated in the one-layer substrate.

The solvent component contained in the resin film functions as a solvent. The resin film is formed by laminating (bonding) the resin film on one main surface of the core substrate, and is heated in a predetermined heating atmosphere. When a curing treatment is performed in an exposure atmosphere, the components are substantially vaporized and finally become components that do not remain in the insulator layer. Therefore, the heat shrinkage of the resin film increases during the process of completely curing and deforming the resin film into a desired insulator layer due to the vaporization of the solvent component. It is assumed that this is the main cause of the warpage that occurs in the single-area wiring board. That is, an increase in the solvent component contained in the resin film also increases the amount of warpage generated in the one-layer wiring board. In that sense, in the present invention, the content of the solvent component contained in the resin film used is set to 4% by weight or less, and if it exceeds 4% by weight, the amount of warpage tends to be excessively increased. The upper limit is set at 4% by weight, which is optimized.

As described above, in the present invention, the warpage generated in the one-layer wiring board can be effectively suppressed. Therefore, in the manufacturing method, for example, the position of a via pattern at a predetermined position of an insulator layer can be reduced. The insulating layer and the wiring layer can be formed with high accuracy, and also when the insulating layer and the wiring layer are formed in a stacked manner, it is possible to form the stacked layers in a form in which the occurrence of the displacement is suppressed with high accuracy. As a result, it is easy to improve the single-area layer wiring board as a product having a desired function without suppressing electrical connection and electrical characteristics, and it is possible to increase the product yield. In addition, by reducing the amount of warpage generated in the single-layer wiring board, the mounting reliability of the mounted electronic component can be increased, and the size of the mounted electronic component, the distance between its connection terminals and the connection. The single-area wiring board can be useful, for example, in that the allowable range such as the terminal height can be easily set.

Next, the number of laminated insulator layers in the build-up layer of the present invention is two or more. When forming an insulator layer using a resin film, the warpage of the core substrate, which occurs due to the heat shrinkage of the resin film that increases in the curing process, naturally accompanies the increase in the number of laminated insulator layers. growing. That is, as the number of stacked insulating layers increases, the amount of warpage generated in the one-layer wiring board cannot be ignored. Therefore, in the case of a single-area wiring board in which two or more insulator layers are formed in the build-up layer, when the insulator layer is formed using a resin film in which the amount of solvent is optimized according to the present invention, the effect is reduced. A more effective single-layer wiring board with more obvious and reduced warpage can be obtained. Also, in manufacturing, when the warpage of the core substrate increases with an increase in the number of stacked insulating layers, the alignment accuracy when forming a via pattern at a predetermined position of the insulating layer, and the insulating layer and The deterioration of the positioning accuracy when the wiring layers are stacked is more remarkable. However, even in the case where the number of laminated insulating layers to be formed in the build-up layer is two or more, by forming the insulating layer using a resin film in which the solvent according to the present invention is optimized, The formation of the via pattern and the lamination of the insulator layer and the wiring layer can be accurately performed, and the product yield can be improved.

As described above, when two or more insulator layers are laminated on the build-up layer, the effect of the resin sheet in which the amount of solvent is optimized according to the present invention is particularly remarkable, and the single-area layer wiring The warpage reduction for the substrate is also more effective. Note that the upper limit of the number of stacked insulating layers in the build-up layer is a common-sense numerical range when shared as a product, and is, for example, about four layers.

Next, the insulating resin material according to the present invention is characterized in that the insulating resin material contains a thermoplastic resin component and the content is 10% by weight or less. The content of the solvent component contained in the resin sheet used in the present invention is 4% by weight or less. Since this solvent component functions as a solvent, as the amount of the solvent component increases, the fluidity of other components is increased during the production of the resin sheet, and the resin sheet is formed without applying a pressure or reducing the applied pressure. Can be produced. Further, a resin sheet having excellent flexibility can be obtained. Therefore, if the applied pressure at the time of producing the resin sheet is increased, the resin sheet used in the present invention can be produced, so that there is no problem. However, since the flexibility of the resin sheet is related to the handling property, there is a problem in operation. It is possible that When taking into account such a viewpoint of improving the handling property in work, it is desirable that the resin sheet of the present invention contains a thermoplastic resin component. As a result, even when the build-up layer is manufactured, the work can be performed with good handling and high efficiency. In addition, by including the thermoplastic resin component in the resin sheet, it becomes possible to increase the adhesion when the resin sheet is formed on the core substrate, and thus, the insulator layer and the core of the insulator layer can be formed. It is also possible to increase the adhesion between the adjacent layers on the substrate side and the bonding strength. Therefore, the content of the thermoplastic resin component contained in the resin sheet is 10% by weight or less because the effect can be sufficiently obtained if it is 10% by weight. In addition, when the amount exceeds the upper limit, the amount of the resin component or the hardener component to be hardened in the hardening process may not be sufficiently obtained, and as a result, the properties such as the mechanical strength of the insulator layer may be reduced. In this sense, the content of the thermoplastic resin component contained in the resin sheet is preferably set to 10% by weight or less. By including a thermoplastic resin component in the resin sheet, an effect of increasing the fluidity of other components during the production of the resin sheet can be expected.

By including the thermoplastic resin component in the resin sheet as described above, it is also possible to increase the bonding strength between the insulator layer in the build-up layer and a layer adjacent to the insulator layer on the core substrate side. He mentioned what is possible. As described above, the bonding strength is increased, and the thermoplastic resin component such as the solvent component does not evaporate and remains in the insulator layer. Therefore, the warpage generated in the core substrate, that is, the one-layer wiring Warpage occurring in the substrate can be further suppressed. Therefore, the content of the thermoplastic resin component contained in the insulator layer of the build-up layer is about 10% by weight or less in consideration that the content contained in the resin sheet is 10% by weight or less. It is desirable to be.

Next, the insulating resin material of the present invention is characterized in that the filler component is contained in a content range of 5 to 30% by weight (5 to 30% by weight). Since the film-shaped insulating resin material used in the present invention, that is, the resin film, has a reduced content of the solvent component, an increase in the content of other components is allowed. Therefore, it is desirable that the filler component be one component that forms the increment. The filler component suppresses the occurrence of prominent fluidity in other components such as the resin component during the curing treatment of the resin sheet. In order to be contained. Further, by increasing the content of the filler component, the usefulness of the effect is increased. This means that by increasing the filler component, it is possible to further suppress the heat shrinkage of components other than the solvent component when the resin sheet is cured. That is, by increasing the filler component, it is possible to further reduce the amount of warpage of the core substrate, and thus the amount of warpage of the one-layer wiring board. The content of the filler component in the resin sheet is preferably in the range of 5 to 30% by weight. If the amount is less than 5% by weight, the effect may not be sufficiently useful. On the other hand, if the amount exceeds 30% by weight, the fluidity of other components is excessively increased when the resin sheet is cured. This is suppressed, and the surface smoothness of the insulator layer may deteriorate. As described above, it is useful to select a filler component as an incremental component that is allowed by a reduced amount of the solvent component in the resin sheet.
Further, when the thermoplastic resin component and the filler component are positively added in the above-mentioned content range, it is possible to further reduce the warpage of the core substrate, and furthermore, the warpage of the one-layer wiring board, in particular. The range of the content of the filler component contained in the insulator layer is about 5 to 30% by weight in consideration of the content of the resin sheet being in the range of 5 to 30% by weight. Good to do.

Next, the core substrate of the present invention is characterized by being made of ceramic. When the core substrate is made of ceramic, the amount of warpage of the core substrate itself, which occurs as compared with the case where the core substrate is made of an organic material, can be effectively suppressed. As a result, it is possible to more effectively suppress the amount of warpage generated in the one-layer substrate. Further, also in the manufacturing method, for example, when forming a via pattern at a predetermined position of the insulator layer, it can be formed with higher positional accuracy, and also when forming an insulating layer and a wiring layer in a stacked manner. It is possible to form the layers in a form in which the occurrence of the displacement is suppressed with higher positional accuracy.

Hereinafter, an embodiment of a one-area wiring board according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view showing one embodiment of a one-area layer wiring board of the present invention. The single-area wiring board 1 has the following structure. On both surfaces of a plate-shaped core substrate 2 (for example, 800 μm in thickness) made of a heat-resistant resin plate (for example, a bismaleimide-triazine resin plate) or a fiber reinforced resin plate (for example, a glass fiber reinforced epoxy resin), The core wiring pattern layers 3 and 13 (for example, a thickness of 20 μm) are formed in a predetermined pattern. These core wiring pattern layers 3 and 13 are formed so as to cover most of the surface of the core substrate 2 and are used as power supply layers or ground layers. On the other hand, a through hole 12 formed by a drill or a laser or the like is formed in the core substrate 2, and a through hole conductor 30 for conducting the core wiring pattern layers 3 and 13 to each other is formed on the inner wall surface. The through hole 12 is filled with a resin filling material 31 such as an epoxy resin.

{Circle around (1)} On the upper layer of the core wiring pattern layer 3, a first insulating layer 4 (for example, a thickness of 30 μm) using the resin sheet shown in the present invention is formed. Further, a first wiring layer 5 (for example, a thickness of 15 μm) is formed on the surface by Cu plating. The core wiring pattern layers 3 and 13 and the wiring layer 5 are interconnected by via conductors 32. Similarly, a second insulator layer 4 using the resin sheet according to the present invention is further formed on the first wiring layer 5. A second wiring layer 5 is formed on the surface by Cu plating. The first and second wiring layers 5 are connected to each other by via conductors 32. The surfaces of the core wiring pattern layer 3 and the first and second wiring layers 5 are formed of a resin film used for forming the upper insulating layer 4 and the insulating layer 4 to be formed. Has been subjected to a surface roughening treatment (for example, a treatment based on a chemical treatment such as a blackening treatment or a chelate etching) in order to increase the adhesion strength.

Next, on the second insulator layer 4, a number of underlying conductive pads 10 that are electrically connected to the second wiring layer 5 are provided. These underlying conductive pads 10 are provided with an electroless Ni—P plating and an Au plating (not shown) on the surface of the wiring layer 5, are arranged in a square shape at a substantially central portion of the substrate, and have solder bumps 11 formed thereon. In addition, it serves as a mounting portion for mounting electronic components such as an IC chip. On the side where the second wiring layer 5 is formed and on the side where the core wiring pattern layer 13 is formed, the solder resist layers 8 and 18 are formed so as to cover the wiring layer 5 and the core wiring pattern layer 13. Is formed. Similarly, a large number of underlying conductive pads 10 electrically connected to the core wiring pattern layer 13 are also provided on the core wiring pattern layer 13 side. The single-layer wiring board 1 can be connected to a motherboard or another wiring board via the base conductive pad 10.

Now, in order to form the insulator layer 4 in the single-area layer wiring board 1 in which the build-up layer having the insulator layer 4 and the wiring layer 5 is formed on one main surface of the core substrate 2 as described above. The content of the solvent component contained in the resin sheet used is set to 4% by weight or less. The insulator layer 4 is formed by laminating a resin sheet on the core substrate 2 by roll lamination or a laminating press, and performing a curing treatment on the resin sheet at a predetermined heating temperature. At this time, if the resin sheet is a photosensitive resin sheet, the curing treatment is performed in a predetermined exposure atmosphere, a heating atmosphere, or both atmospheres. During this curing treatment, the solvent component is substantially vaporized, so that excessive heat shrinkage occurs during a deformation process in which the resin sheet is completely cured and becomes an insulator layer. As shown in the schematic diagram of FIG. 2, the resin sheet 71 laminated on the substrate main body 70 having the core substrate as a base contracts toward the inside of the substrate main body 70 during the curing treatment. Then, a concave warp occurs on the upper side. In addition, the amount of warpage basically increases according to the number of insulator layers to be formed, although the rate of increase decreases. Therefore, in the present invention, the content of the solvent component contained in the resin sheet used for forming the insulator layer is optimized to 4% by weight or less. As a result, the one-area layer wiring board of the present invention can be made such that warpage is effectively suppressed. In addition, even in the manufacture thereof, it is possible to increase the product yield and the like, for example, in which the alignment accuracy in each step is prevented from being deteriorated by the warpage of the core substrate.

The solvent component contained in the resin sheet according to the present invention is not particularly limited and may be a known solvent component. Examples thereof include xylene, ethylene glycol monoethyl ether acetate, and ethylene glycol monomethyl ether acetate. , Diethylene glycol monomethyl ether, N, N'-dimethylacetamide, cyclohexanone, C4 alkylbenzene, N, N-dimethylformamide and the like. What is illustrated here is that which is substantially vaporized at a heating temperature of 150 to 200 ° C. when the curing treatment is performed on the resin sheet. In this sense, a known material having a boiling point not higher than the heating temperature range and functioning as a solvent in the resin sheet is appropriately selected as the solvent component.

Now, the content of the solvent component contained in the resin sheet according to the present invention is set to 4% by weight or less, but the lower limit is not particularly limited. That is, the range in which the solvent component is 0 is also included. Here, examples of the resin sheet having a solvent component of 0 include a prepreg (for example, a glass fiber reinforced epoxy resin) in which a glass substrate such as a glass cloth is impregnated with a resin, a known dry film, and the like. .

(4) The resin sheet has a proper content of the solvent component as described above, and particularly preferably contains a thermoplastic resin component. By including this component, the flexibility of the resin sheet due to the reduction of the solvent component can be compensated for. Furthermore, when the one-layer wiring board is used for an application corresponding to a high-frequency signal, it contributes as a useful component from the viewpoint of reducing the dielectric constant of the insulator layer. The thermoplastic resin component may be appropriately selected from known thermoplastic resins, and examples thereof include butadiene oxide and polyether sulfone. Next, the content of the filler component contained in the resin sheet is preferably 5 to 30% by weight. By reducing the solvent component, it becomes possible to widen the range of the content of the filler component that can be contained in this manner. As a result, the content of the filler component can be increased, and furthermore, it is possible to further reduce the amount of warpage generated in the one-layer wiring board. Here, as the filler component, a known one such as a silica filler, an epoxy filler, and bentonite may be appropriately selected and used.

Next, the resin component contained in the resin sheet used in the present invention is a main component (for example, a content of 70 to 90% by weight) of the resin sheet, and It is a fundamental component for ensuring mechanical and electrical properties such as strength, heat resistance and insulation. Therefore, an epoxy resin is particularly preferably used as the resin as the resin component, and it is preferable that the resin sheet contains the epoxy resin as a main component. Examples of the resin that forms the resin component and is the main component in the resin sheet include polyimide, polytetrafluoroethylene, brominated bisphenol A epoxy resin, bisphenol A epoxy resin, and bisphenol F epoxy resin. In particular, it is preferable that the resin sheet contains an epoxy resin as a main component because it is inexpensive and is excellent in securing mechanical and electrical characteristics of the insulator layer. In this specification, the main component means that the weight content of the main component is higher than the weight content of any other substance alone. Further, the epoxy resin is a general term for a substance having two or more epoxy rings composed of two carbon atoms and one oxygen atom in one molecule and capable of forming a three-dimensional structure.

As described above, it is desirable that the resin sheet contains an epoxy resin as a main component.In addition to the epoxy resin, for example, polyimide is used for various purposes such as polyimide from the viewpoint of further increasing heat resistance. It may be contained as a component. When the above-mentioned thermoplastic resin components are contained, these are also regarded as resin components.

よ う As described above, the resin sheet contains a resin component, a filler component, a solvent component, and the like at a predetermined ratio according to each purpose. Various components such as a curing agent component, a flame retardant component, and a photosensitive component may be added to the resin sheet.

In addition, the resin sheet is roughly classified into a photosensitive resin sheet, a thermosetting resin sheet, and a resin sheet with a copper foil in a form depending on a manufacturing method at the time of forming the build-up layer. Can be. The photosensitive resin sheet is used for the purpose of performing the curing process in an exposure atmosphere, a heating atmosphere, or both atmospheres, and performing the through-hole formation in the insulator layer by the exposure process using ultraviolet irradiation through a mask. Is done. The thermosetting resin sheet is used for the purpose of performing a curing process in a heated atmosphere and forming a through hole in the insulator layer by a laser irradiation process. Finally, the resin sheet with copper foil is cured in the same manner as the thermosetting resin sheet, but the copper layer located on the upper layer is etched by using the subtractive method to form a wiring layer. And can be used for such purposes.

材料 The above materials can be selected as the resin sheet. In the photosensitive resin sheet, the photosensitive resin component must be contained, and therefore, the characteristics of other resin components may be sacrificed, and depending on the selection of the component to be contained including the photosensitive resin component. It is assumed that the reduction of the content of the solvent component is hindered. The resin sheet with a copper foil is produced by applying a thermosetting resin contained in an insulating resin material to a copper foil in a B-stage (semi-cured) state. Therefore, it is necessary to ensure adhesion and stability between the insulating resin material and the copper foil, and in consideration of the aspect, it is assumed that reduction of the content of the solvent component is hindered. However, in comparison with these, in the thermosetting resin sheet, the components to be contained and the content thereof can be freely selected. Therefore, the resin sheet used in the present invention should be a thermosetting resin sheet. Is particularly preferred.

Next, an example of the manufacturing method including the single-area wiring board shown in FIG. 1 will be described below.
First, a plate-shaped core substrate made of a heat-resistant resin material (for example, bismaleimide-triazine resin material) or a fiber-reinforced resin material (for example, glass fiber-reinforced epoxy resin) is formed. Then, through holes are drilled at predetermined positions on the core substrate with a drill or laser. Next, a core wiring pattern layer composed of a predetermined wiring pattern is formed on both main surfaces of the core substrate, and a through-hole conductor that is electrically connected to the core wiring pattern layer is formed on the inner wall surface of the through-hole. These core wiring pattern layers and through-hole conductors are formed from metal conductors such as copper, and a subtractive method is used when a conductor foil such as copper foil is previously formed on the main surface of the core substrate, and an additive method otherwise. Formed at In addition, as shown in FIG. 1, the core substrate on which the core wiring pattern layer and the through-hole conductor are formed is not used only in one layer, but when a plurality of layers are used, as shown in the upper part of the schematic diagram of FIG. For example, the core substrate 2 on which the core wiring pattern layer 3 having a predetermined wiring pattern is formed on the core substrate 2 having the conductor foil 72 such as a copper foil formed on the surface thereof, with the prepreg 71 interposed therebetween. By performing the laminating press process in the sandwiched shape, the core substrate 2 having the core wiring pattern layer 3 formed therein as shown in the figure below can be obtained. Then, through holes are drilled at predetermined positions of the core substrate 2 with a drill or a laser, and a core wiring pattern layer is further formed on both main surfaces of the core substrate 2 by a subtractive method. Conductors are respectively formed. Thus, the core wiring pattern layer is formed on both main surfaces of the core substrate in the same manner as in FIG. 1 only by the difference between the presence or absence of the core wiring pattern layer inside the core substrate.

(4) After forming the core wiring pattern layer and the through-hole conductor on the core substrate as described above, the through-hole is filled with, for example, a resin filling material. Thus, a substrate main body for forming a build-up layer is formed. Thereafter, a resin sheet is formed by lamination on one main surface of the substrate body, that is, on one main surface of the core substrate. The lamination is performed by a lamination press method, a roll lamination method, or the like. Particularly, it is performed in a vacuum chamber. Then, by performing these laminations and performing a curing treatment, an insulator layer is obtained. This curing treatment is carried out at the time of lamination, at a time after lamination under a predetermined atmosphere, or both. After forming the insulator layer in this manner, a via hole is formed at a predetermined position of the insulator layer, and a wiring layer and a via conductor having a predetermined wiring pattern are formed by Cu plating, whereby the insulator layer is formed. A wiring layer is formed on the surface. In the case where a plurality of insulator layers and wiring layers are formed, this operation is repeated so that the build-up layers are multi-layered.

ビ ル ド As described above, a build-up layer having an insulator layer and a wiring layer is formed on one main surface of the core substrate. Further, when laminating the resin sheet on one main surface of the substrate main body including the core substrate and performing the curing treatment, it is also possible to fill the through holes of the substrate main body with the resin component of the resin sheet. In this case, the resin sheet is laminated on the substrate body that is not filled with the through-holes, so that the working efficiency can be improved. Furthermore, by using the resin sheet according to the present invention, it is possible to suppress the warpage generated in the core substrate during the curing treatment, so that the through holes can be more uniformly filled with the resin component.

Although the embodiments according to the present invention have been described above, the present invention is not limited to these embodiments. For example, regarding the material of the core substrate, a ceramic material can be used in addition to the organic material. The former organic material may be a material containing glass fiber or carbon fiber.Specifically, in addition to the above-mentioned bismaleimide-triazine resin and glass fiber reinforced epoxy resin, a polyimide-based resin and continuous pores It is also possible to use a composite material in which a glass fiber or the like is contained in a fluororesin having a three-dimensional network structure such as PTFE having a three-dimensional network structure. As the latter ceramic material, for example, a material containing alumina, silicic acid, glass ceramic, aluminum nitride, or the like can be used, and further, a material that can be fired at a relatively low temperature of about 1000 ° C. or less is used. You can also. Even when a ceramic substrate is used as a core substrate, including a low-temperature fired substrate made of a ceramic material that can be fired at a low temperature, if the substrate is regarded as the core substrate 2 in FIG. Can be used to form a similar build-up layer.

As described above, as the material of the core substrate, an organic material or a ceramic material can be used. In particular, it is desirable that the core substrate be made of ceramic. By making the core substrate made of ceramic, the core substrate itself can be made less likely to warp, and thus the amount of warpage generated in the single-layer substrate can be more effectively suppressed. Further, also in the manufacturing method, for example, when forming a via pattern at a predetermined position of the insulator layer, it can be formed with higher positional accuracy, and also when forming an insulating layer and a wiring layer in a stacked manner. It is possible to form the layers in a form in which the occurrence of the displacement is suppressed with higher positional accuracy.

The production of the core substrate, which is a ceramic substrate, can be performed, for example, as follows. First, through holes are formed in a ceramic green sheet made of unfired alumina or the like by laser processing or metal processing. Next, a conductive paste containing a metal powder such as W is printed and filled in the through holes. The conductive paste is simultaneously fired when the ceramic green sheets are fired to form through-hole conductors. Also, a conductive paste is printed in a predetermined wiring pattern at a predetermined position on the surface of the ceramic green sheet. The conductive paste printed on the surface is simultaneously fired at the time of firing the ceramic green sheet to form a core wiring pattern layer.
Further, a single or multiple layers of unfired ceramic green sheets on which the conductive paste is printed are laminated and thermocompression-bonded to form an unfired core substrate. Then, by firing the unfired core substrate at about 1300 ° C., a single-layer or multiple-layer core substrate is obtained. When the ceramic substrate is used as the core substrate, the resin filling material 31 is not formed inside the through hole 12 as shown in FIG. Then, an insulating layer made of a resin film or the like is sequentially formed on the surface of the core substrate thus formed, whereby a build-up layer similar to the above is formed.
In addition, as a material of the above-mentioned conductive paste, in addition to W, for example, Mo or Cu, furthermore, Ag, Au, Ag-Pt, Ag-Pd, or the like can be used. In addition to the Cu, Ag, Ni, and Ni—Au-based materials can be used as the material of the through-hole conductor and the core wiring pattern layer, including the core substrate made of an organic material. A method such as applying a conductive resin without using a resin can be used.

実 施 Examples performed to confirm the effects of the present invention are shown below.

First, a core substrate made of a bismaleimide-triazine resin was prepared. Further, it was formed so as to be a rectangular body having a height of 0.8 mm and an area of 400 × 500 mm ² . Further, a conductor foil made of copper foil was laminated on only one main surface of the core substrate by a lamination press. The layer thickness of this conductor foil was 12 μm. After preparing the substrate body in this manner, a resin sheet having various compositions is coated on the surface of the conductor foil of the substrate body by roll lamination, and the resin component is heated under a heating atmosphere at 150 to 175 ° C. It was completely cured to form an insulator layer. Further, in order to make the number of stacked insulating layers various, insulating layers were sequentially formed under the same method and conditions. As shown in the schematic diagram of FIG. 4A, test pieces in which various numbers (1 to 3 layers) of the insulating layers 4 were formed on the surface of the substrate main body 70 were prepared. The thickness of each of these insulator layers was 33 μm. Further, the insulator layer in one test article was formed using a resin sheet adjusted to the same composition. Table 1 shows the composition of the resin sheet used in the test sample thus formed.

反 The amount of warpage was measured for each of the test pieces (Nos. 1 to 9) prepared as described above. As shown in the schematic diagram of FIG. 4B, the test specimen 73 having a concave warp on the insulator layer 4 side was supported by a support 74 using a height gauge, and then measured in a layer thickness direction. Was measured for the maximum height h1. The layer thickness h2 at that position was measured, and the value obtained by dividing h2 from h1 was defined as the amount of warpage.

FIG. 5 is a diagram in which the amount of warpage obtained in the above measurement is plotted against the amount of solvent contained in the resin sheet for each number of laminated insulating layers. The amount of warpage is standardized by the amount of warpage of each of Test Samples 1 to 3, with the amount of solvent contained in the resin sheet being 13.2% by weight. As is clear from the figure, the amount of warpage decreases as the amount of solvent contained in the resin sheet decreases. By setting the amount of the solvent to at least 4% by weight or less, the generated warpage can be effectively reduced. In addition, the rate of decrease in the amount of warpage due to the decrease in the amount of solvent increases as the number of stacked insulating layers increases. In other words, the effect of reducing the amount of generated warpage becomes more remarkable by setting the amount of the solvent to at least 4% by weight with respect to the increase in the number of stacked insulating layers.

According to the above-described embodiment, by optimizing the content of the solvent component contained in the resin sheet to 4% by weight or less, it is possible to effectively reduce the amount of warpage generated in the core substrate and, consequently, the one-layer wiring board. It was proved. No. 4 to 9 were formed using a resin sheet containing a thermoplastic resin component, but no decrease in flexibility due to a decrease in the solvent component was observed in the work, and the work could be performed with good handleability. Was. In addition, even when the resin sheet was laminated on the substrate body, the resin sheet could be covered without lowering the adhesiveness.

Finally, No. 4, no. Composition analysis was performed on the surface of the insulator layer of No. 7 by EPMA (Electron Probe Microanalysis) measurement. As a result, no. The content of the thermoplastic resin component contained in the insulator layer of No. 4 was 5% by weight, and the content of the filler component was 11.6% by weight. The content of the thermoplastic resin component contained in the insulator layer of No. 7 was 5% by weight, and the content of the filler component was 10.7% by weight.

Note that the present invention is not limited to the above-described embodiments and examples. In a single-area wiring board requiring warpage reduction, the insulating layer of the build-up layer is formed with a solvent component of 4% by weight. What is formed using the following resin sheets is included in the present invention.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a single area layer wiring board of the present invention. Schematic diagram for explaining the effect of the resin sheet according to the present invention FIG. 4 is a schematic diagram for explaining a manufacturing process relating to the one-area wiring board of the present invention. FIG. 2 is a schematic diagram for explaining a test article and a measurement method according to the present embodiment. FIG. 7 is a diagram showing measurement results of the present example.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Single-layer wiring board 2 Core board 3 Core wiring pattern layer 4 Insulator layer 5 Wiring layer

Claims (9)

Only one main surface of the core substrate, a method for manufacturing a single-area layer wiring board to form a build-up layer having an insulator layer and a wiring layer,
The insulator layer is formed by coating a film-shaped insulating resin material on one main surface of the core substrate and performing a curing process;
In addition, in order to suppress warpage generated in the one-layer wiring board due to thermal shrinkage of the insulating resin material in the curing treatment, the content of the solvent component contained in the insulating resin material is set to 4% by weight or less. A method for manufacturing a single-area wiring board, comprising: 2. The method according to claim 1, wherein the number of the insulating layers laminated in the build-up layer is two or more. The method according to claim 1, wherein the insulating resin material contains a thermoplastic resin component, and a content of the thermoplastic resin component is 10% by weight or less. 4. 4. The single-layer wiring board according to claim 1, wherein the insulating resin material contains a filler component in a content range of 5 to 30% by weight. Method. 5. The method according to claim 3, wherein the insulating resin material contains an epoxy resin as a main component. The method according to any one of claims 1 to 5, wherein the film-shaped insulating resin material is a thermosetting resin film. 7. The method according to claim 1, wherein the core substrate is made of ceramic. A single-area layer wiring board in which a buildup layer having an insulator layer and a wiring layer is formed only on one main surface of the core substrate,
The insulator layer is formed by coating a film-shaped insulating resin material on one main surface of the core substrate and performing a curing process,
In addition, in order to suppress warpage generated in the one-layer substrate due to heat shrinkage of the insulating resin material in the curing treatment, the content of the solvent component contained in the insulating resin material is set to 4% by weight or less. A single-layer wiring board, comprising: The single-layer wiring board according to claim 8, wherein the core substrate is made of ceramic.

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