JP2002141637A - Printed-wiring board and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed-wiring board that can be manufactured by a simple process, is inexpensive, and has improved quality in circuit conductivity reliability, connection adhesion strength, and circuit position accuracy, to provide the manufacturing method of the printed-wiring board, and further to provide the printed-wiring board with a wide application range for applying to a multilayer printed-wiring board, a build-up printed-wiring board, a printed-wiring board with a cavity, and a smoothing substrate, and the like. SOLUTION: In the method for manufacturing the printed-wiring board by etching a conductive material layer in two steps, the following processes are executed, namely a first etching process for forming a circuit pattern by partially etching the partial thickness of the conductive material layer, a lamination process for burying a circuit pattern into a resin layer by laminating a circuit formation surface and the insulating resin layer, a process for forming an insulating resin layer at least between circuits of the circuit formation surface, and a second etching process for performing partial etching for leaving a desired section as needed in the remaining thick section of the conductive material on the circuit pattern, or the total surface etching of the remaining thick section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board with fine projections, a method for manufacturing double-sided and multilayer printed wiring boards using the same, a printed wiring board with a cavity, a pattern-on pattern board, and a pattern-on pattern board. The present invention relates to a method for manufacturing a pad substrate. Further, the present invention relates to a method for manufacturing a smooth substrate obtained by performing the second etching on the entire surface of the remaining portion of the conductor. In the present invention, the minute projection is a projection formed on a circuit pattern, and is used to establish an electrical connection with a functional component mounted on a printed wiring board directly or by bonding or the like. In addition, when the printed wiring board is multi-layered, the fine protrusions are formed in the first layer, the subsequent second layer, the third layer, and so on.
Also used to make electrical connections between layers to ...

[0002]

2. Description of the Related Art Conventionally, fine projections have been formed, for example, by the following method after a circuit pattern has been formed in advance. (1) A conductive paste such as a silver paste or a copper paste is printed on a circuit pattern by screen printing to form minute projections. (2) It is formed by metal plating. (3) Formed with solder balls.

[0003] However, the conventional method of forming minute projections has the following disadvantages. (I) The circuit pattern is generally formed of copper or the like. However, since the minute projections are made of a material different from the material of the circuit pattern such as a cured conductive paste or solder, particularly the connection portions between the circuit pattern and the minute projections and the minute projections are formed. At the connection between the projection and the mounted component, unfavorable phenomena such as electrical resistance and thermal resistance have occurred in electrical characteristics. (Ii) Since the fine projections formed by the conductive paste, solder, plating, and the like are additionally formed on the circuit pattern, the adhesion to the circuit pattern surface was poor, and the connection reliability was low. (Iii) It is difficult to obtain a uniform height of the tips of the projections formed by plating, metal balls, conductive paste by screen printing, etc., and therefore, a new conductor layer is formed via an insulating layer. When the conductive connection is achieved by stacking layers, it is difficult to obtain uniform electrical conductivity with the new conductive layer, which is partially incomplete or has a variation in connection resistance. (Iv) In addition, since it is difficult to form the fine protrusions uniformly and firmly in height, it can be applied to a thin plate or a low-layer printed wiring board, but is not suitable for forming a thick plate or a high-layer printed wiring board. Was not applied due to quality variations and lack of connection reliability.

A conventional build-up wiring board has been formed, for example, by the following method. (1) After a circuit pattern is formed on a conductor layer on an insulating resin, a photosensitive photosensitive resin layer is formed thereon, and exposure and development are performed only on a small portion for conducting connection with a conductor layer formed thereon. The resin layer is opened, conduction is formed between the resin surface and the opened hole by plating, and a second circuit pattern is formed in the conductive layer. These steps are repeated for the number of build-up layers. (2) In (1), a thermosetting resin is used in place of the photosensitive resin, holes are formed by drilling or laser processing, and each process is repeated for the number of build-up layers. (3) An eclectic method of laminating a rigid IVH layer with a circuit pattern and perforated conduction on the intermediate layer by the method of (1) or (2). (4) A circuit pattern is formed on the conductor layer on the insulating resin layer, and a conductive paste is formed on a desired conductive portion on the pattern by printing or the like to form Fuji-shaped minute projections and cured.
An insulator layer and a conductor layer are stacked thereon, and the minute projections penetrate the insulator layer to form conduction with the conductor layer. Next, the next circuit pattern is formed on the conductive layer thus conducted, and each step is repeated for the number of layers required as a build-up wiring board.

[0005] However, these build-up methods have the following disadvantages. (I) Photocurable insulating resin is inferior in heat resistance and bending strength,
In addition, there is a limit to the thickness of the insulating resin layer in opening a hole by light exposure, and although it is applicable to a thin printed wiring board, it is not suitable to be thick. (Ii) When drilling holes in an insulating resin layer, it is extremely difficult to drill holes in only a thin insulating layer and drill them without scratching the conductor layer underneath. It is difficult to clean the drilled hole wall cleanly and it is difficult to eliminate the residual insulating resin on the conductive layer at the bottom of the hole. Poor reliability. (Iii) The process is complicated and costly. (Iv) If the opening of the hole and the continuity with the upper circuit pattern are formed by the formation of minute projections of the conductive resin, the conduction resistance is high and the electrical reliability is poor. Is difficult to process and has poor conduction reliability.

Further, the cavities of a conventional printed wiring board with a cavity are formed by the following method. (1) After creating a double-sided or multilayer printed wiring board or a build-up wiring board, the cavity is counterbored as post-processing. (2) A desired cavity is formed in the photosensitive insulating resin layer by exposure and development.

[0007] However, these conventional methods have the following disadvantages. (I) Counterboring by post-processing has poor processing accuracy, the shape of the cavity is limited, and it is difficult to process a thin cavity layer. (Ii) A photosensitive insulating resin is not suitable for processing a printed wiring board having a thick insulating resin layer because it is difficult to form a cavity in a thick insulating layer, and is inferior in heat resistance and mechanical strength.

Conventional pattern-on-pattern printed wiring boards and pattern-on-pad printed wiring boards have been formed by the following method. (1) The connection between the lower layer pattern and the pattern or pad provided in the upper conductor layer is determined by printing a conductive paste on the lower layer pattern or forming an insulating layer and then forming a conduction hole in a desired portion. An upper layer pattern or pad is provided by plating.

[0009] However, these conventional methods have the following disadvantages. (I) Poor electrical connection reliability. (Ii) The process is complicated, productivity is low, and cost is high.

On the other hand, a conventional smooth printed wiring board has been formed by the following method. (1) This method is called a transfer method. One side of a thin metal plate such as stainless steel is plated thinly, a plating resist is formed on the plated surface, and a circuit pattern is formed by plating to remove the resist. Then, the pattern surface is embedded in the insulating resin layer by lamination under heat and pressure, and then the thin metal plate and the thin plating layer are removed by peeling or etching with a chemical. (2) This method is called a resin coating method. A circuit is formed by etching on a copper foil surface such as a copper-clad laminate, and an insulating resin layer is formed on the upper surface by coating or the like, cured and dried, and then protruded from the circuit surface. The resin in the removed portion is removed by mechanical polishing or the like. (3) This is called the resin-coated copper foil method. A resin-coated copper foil, which is thicker than the thickness of the copper foil and does not contain fillers and is laminated with a copper foil, is used to form a circuit pattern on the copper foil surface. Is formed, if necessary, a prepreg or a rigid layer is laid up on the resin surface, and the circuit pattern is embedded in the semi-curable insulating resin under heat and pressure.

However, these conventional methods have the following disadvantages. (I) In the transfer method, the circuit is likely to be displaced or deformed, the circuit accuracy is deteriorated, and the circuit is easily damaged in the step of removing the thin metal plate. (Ii) In the resin coating method, since there is a step between the circuit and the resin surface etched out, it is difficult to uniformly coat the insulating resin thereon, and the extra resin thickness on the circuit surface after the coating resin is cured. Damage the circuit when mechanically polishing and removing parts. (Iii) Although the resin-coated copper foil method has an advantage that the circuit is damaged and the circuit accuracy is good, it is limited to the material of the resin-coated copper foil. Therefore, it is suitable for a thin copper foil, that is, a thin circuit pattern. Not suitable for thick copper foil, that is, thick circuit patterns.

[0012]

SUMMARY OF THE INVENTION The present invention solves many of these problems and provides a printed wiring board with microprojections excellent in strength, electrical characteristics and inter-layer connection reliability by a two-stage etching method. It is intended to provide a manufacturing method. The present invention also provides a double-sided or multilayer printed wiring board to which the above-mentioned printed wiring board with minute projections is applied or utilized, and a method for producing the same. The present invention also provides a build-up printed wiring board using the printed wiring board with minute projections and a method for manufacturing the same. The present invention further provides a printed wiring board with a cavity and a method for manufacturing the same using the printed wiring board with minute projections. The present invention further provides a pattern-on-pattern printed wiring board, a pattern-on-pad printed wiring board, and a method of manufacturing the same, using the printed wiring board with minute projections. The present invention also provides a smooth printed wiring board to which a two-stage etching method is applied and a method for manufacturing the same.

[0013]

According to the method of manufacturing a printed wiring board with minute projections of the present invention, a printed circuit board with minute projections is formed by integrally forming a circuit pattern and minute projections by etching a conductive layer in two steps. A first etching step of partially etching a part of the thickness of the conductor layer to form a circuit pattern; and laminating a circuit formation surface and an insulating resin layer to form a circuit pattern in the resin layer. A laminating step of embedding a circuit pattern, or a step of forming an insulating resin layer at least between circuits on a circuit forming surface, and a partial etching for selectively leaving a desired portion of the conductor remaining thickness portion on the circuit pattern as necessary. The method is characterized in that a second etching step is performed to form a minute projection remaining integrally with the circuit pattern.

In the double-sided or multi-layer printed wiring board of the present invention, the second conductor layer is integrated with the fine projection-formed surface of the printed wiring board with fine projections via an insulating layer. The micro-protrusion is penetrated through the insulating layer, and the micro-protrusion conductor is brought into contact with the second conductor layer to form an electrical continuity. Is characterized in that it is electrically connected to the power supply. At this time, a circuit pattern or fine projections may be formed in advance on the conductor layer, or they may be formed after lamination. Further, the present invention can be carried out on one side of a printed wiring board having microprojections as a base, or can be carried out on both sides.

According to the method of manufacturing a build-up printed wiring board of the present invention, a conductive layer is laminated on a printed wiring board having fine projections via an insulating layer, and electrically connected to the conductive layer laminated by the fine projections. It forms conduction.

In the method of manufacturing a multilayer printed wiring board with a cavity according to the present invention, one or more layers having a cavity are laminated, and electrical conduction between the layers is obtained by the fine projections manufactured in claim 2. The cavity is formed in the multilayer printed wiring board manufactured by the third and fourth aspects by post-processing.

The method of manufacturing a pattern-on-pattern printed wiring board and a pattern-on-pad printed wiring board according to the present invention comprises the steps of:
The shape of a desired portion left in the conductor remaining thickness portion by the partial etching is a pattern shape or a pad shape by the partial etching.

Further, in any of the build-up printed wiring board, the printed wiring board with a cavity, the pattern-on-pattern printed wiring board and the pattern-on-pad printed wiring board of the present invention, when conducting, a circuit pattern and Fine projections may be formed,
They may be formed after lamination, or they may be formed on one side of the underlying printed wiring board with microprojections, or may be formed on both sides.

According to the method of manufacturing a smooth printed wiring board of the present invention, in the printed wiring board manufactured according to the first aspect, the second etching is an entire surface etching.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIGS.
As shown in FIG. 9, an etching resist 2 is formed on both surfaces of the conductor layer 1 and exposed and developed so as to form a required circuit pattern 3 on one surface, and then a semi-curable insulating film is formed on the formed circuit pattern 3 surface. By laminating the resin layer 5 and, if necessary, the rigid insulating resin layer 6 under heat and pressure and embedding the circuit pattern 3 in the semi-cured insulating resin 5, the insulating resin 5
The circuit pattern 3 is completely buried and fixed in the cured insulating resin layer 7 in which the circuit patterns 3 and 6 are integrated. Then, as shown in FIG. 7, an etching resist is applied to the surface of the conductor layer remaining portion 4 and exposed and developed to form an etching resist 8 for the minute projections 9 and then the conductor residue is formed by etching. An unnecessary surface of the thick portion 4 is etched out and removed, and minute projections 9 as shown in FIG. 8 are formed integrally with the circuit pattern 3 to form a printed wiring board with minute projections. FIG. 8 shows the obtained single-sided printed wiring board with minute projections.

In the second embodiment of the present invention, after FIG. 4, the surface of the circuit pattern 3 is coated with an insulating resin to a thickness at which the height of the circuit pattern 3 can be embedded at least, and after curing, the surface of the circuit pattern 3 shown in FIG.
By performing the same steps as those described below, a printed wiring board with fine projections is formed, as shown in FIG. 9, in which the circuit surface and the insulating resin surface become smooth. At the time of resin coating, if the thickness is made larger than the height of the circuit pattern 3 as necessary, a printed wiring board with minute projections as shown in FIG. 8 can be formed by the coating method.

The third embodiment of the present invention is shown in FIG. 10, in which two circuit patterns 3 are formed on the conductor layer 1 as obtained in FIG. As shown in FIG.
A double-sided printed wiring board with fine projections is formed by performing lamination and forming fine projections as shown in FIGS. Here, the two circuit patterns need not necessarily be the same pattern, but rather are usually different, and FIG. 10 is merely model-wise provided, and the circuit and the way of providing the circuit are not limited at all. Absent. Note that the insulating resin layer is not limited to the semi-curable insulating resin, and a rigid base material 6 may be provided as shown in FIG. These non-limiting items are the same in the following embodiments.

In the fourth embodiment of the present invention, as shown in FIGS. 11 and 12, a multi-layer printed wiring board with fine projections is formed. That is, in the process of forming the double-sided printed wiring board with fine projections obtained in FIG. 10, a double-sided printed wiring board with circuits is provided alongside the inner layer to form a multilayer printed wiring board with fine projections as shown in FIG. is there.

In the fifth embodiment of the present invention, as shown in FIG. 12, a desired portion of each of the inner layer and the outer layer is formed with an IVH substrate in the inner layer by plating or the like, and a through hole is formed in the outer layer-inner layer connection. Thus, a multilayer printed wiring board with minute projections is formed. In any of the embodiments, the double-sided printed wiring board provided in the inner layer may be a smooth substrate as shown in FIG. 21, and the method of manufacturing the smooth substrate is not limited. Further, the conduction method for the inner layer IVH, BVH, through hole, and the like is applied to any embodiment of the present invention, and is not limited to the implementation.

In the sixth embodiment of the present invention, as shown in FIG. 12, an outer layer pattern 17 is formed at a desired portion at the time of forming an outer layer minute projection to form a multilayer printed wiring board with minute projections.

A seventh embodiment of the present invention is shown in FIGS. 13 to 17 and is connected to an upper conductive layer without applying a microprojection and performing drilling or through-hole plating for conduction. A multilayer printed wiring board formed by forming continuity is formed. First, the inner layer circuit board having the microprojections 9 formed on the inner layer circuit 3 is overlapped with the upper conductor layer 15 via the semi-cured insulating resin layer 16 and laminated under heat and pressure, as shown in FIG. A multilayer printed wiring board is formed by forming a pattern 17 and a pad 18 on a desired portion of the outer layer other than the fine protrusions as necessary by etching the outer layer circuit. At this time, the microprojections 9 formed in the inner layer by lamination under heating and pressure are applied to the semi-curable insulating resin layer 1.
In order to pierce through the conductive layer 6 and to form a conductive connection with the upper conductive layer 15 with higher reliability, the shape of the minute projection must be changed as shown in FIG.
It is desirable to exhibit a Fuji type or a sharp type as shown in FIGS. However, even if the shape of the minute projection is a straight type as shown in FIG. 13, the connection reliability is not impaired at all. The microprojections can be easily formed by selecting the type of etching solution and etching conditions, or by performing two-step etching of the straight microprojections in order to form the Fuji type or the sharp type.

In the eighth embodiment of the present invention, as shown in FIG. 18, a build-up multilayer printed wiring board is formed by utilizing minute projections for conduction. That is, the inner circuit pattern 3 formed by the first etching is laminated and embedded in the semi-curable insulating resin layer 5, and then the second circuit pattern 3 is formed.
Micro-projections 9 at desired portions on pattern 3 by etching
First, a first layer is formed as a basic form of the present invention as shown in FIG. 8, and then a circuit pattern of an upper layer as a second layer is similarly formed as shown in FIG.
To form a conductive connection with the minute projections 9 on the first layer by heating and pressing on the first layer. Thereafter, by repeating the same lamination conduction for the required number of layers, a build-up high multilayer printed wiring board as shown in FIG. 18 is formed with high accuracy and efficiency. At this time, the shape of the tip of the minute projection may be an acute angle like the minute projections 9 'and 9''shown in FIGS.

The ninth embodiment of the present invention is an application of the build-up multilayer printed wiring board of the eighth embodiment shown in FIG.
The multilayer printed wiring board with a cavity as shown in FIG. One or more layers 16 ′ having the cavities 22 are laminated, and electrical continuity between the respective layers is achieved by the minute projections 9 formed at desired portions on the circuit pattern 3 according to claim 1 and 2. It is formed like a form. After the build-up wiring board as shown in FIG. 18 is formed, the necessary portions of each layer are counterbored by a conventional method as a post-process, and a similar printed wiring board with a cavity can be formed as a cavity. The electronic components 23 mounted in the cavities are connected 24 to the microprojections 9 on the bottom of the cavity, or connected to the respective layers such as the microprojections 9 in the respective layers.
Is connected by wire bonding 25 or the like. Also,
As a countermeasure against heat generation from electronic components and wiring, for example, the heat dissipation conductor layer 21 can be formed in the bottommost layer at the time of the first etching, or the component itself can be resin-sealed 26 in each cavity.

In the tenth embodiment of the present invention, a smooth printed wiring board as shown in FIG. 20 is formed. That is, as shown in FIG. 6, after the circuit pattern 3 obtained by the first etching is embedded in the insulating resin layer 7 and hardened, the remaining portion 4 of the conductor layer is entirely etched by the second etching. This forms a smooth printed wiring board in which the plane of the circuit pattern 3 and the plane of the insulating resin layer 7 are completely smoothed.

In the eleventh embodiment of the present invention, as shown in FIG. 21, a tenth embodiment is applied to a two-sided printed wiring board to form a two-sided smooth printed wiring board.

[0031]

EXAMPLE 1 Using a 70 μm thick copper foil for the conductor layer, using a dry film as an etching resist, exposing and developing through a pattern mask film, and forming a circuit pattern of 30 μm with an iron chloride type etching solution. After etching to a depth and subjecting the circuit pattern surface to a blackening treatment,
130 ° C x 3 via 2mm thick epoxy prepreg
A circuit pattern is buried and fixed in an insulating resin by laminating under 20 kg / cm ^{2 for} 0 minutes, and then a dry film is laminated again on the remaining copper foil having a conductor thickness of 40 μm and a thickness of 1.0 mm. After exposure and development to form fine protrusions having a diameter, a second etching was performed with an iron chloride etching solution, and the resist was peeled off to form a printed wiring board with fine protrusions.

Example 2 In the first example, an ink-like epoxy resin was used as a semi-curable insulating resin, and the circuit pattern surface was subjected to a printing method so that the entire circuit pattern height was buried, and was cured by heating.
A smooth printed wiring board having a uniform circuit pattern surface and an insulating resin surface was formed.

Embodiment 3 In the first embodiment, two sets of an epoxy-based semi-curable sheet not containing a filler such as glass fiber were prepared on the circuit pattern side, inserted into a laminator with the sheet faces facing each other, and heated. The two layers were laminated under pressure to form a double-sided printed wiring board with fine projections as shown in FIG.

Embodiment 4 In the third embodiment, a smooth printed wiring board having a pattern thickness of 35 μm of a copper circuit pattern formed by a transfer method is sandwiched between two sets provided with an epoxy resin prepreg as an insulating resin layer. 170 ° C. × 60 minutes in a laminating press, 20
After laminating under the condition of kg / cm ² , the second etching was performed with an alkaline etching solution so that the fine protrusions had a diameter of 0.5 mm, thereby forming a four-layer printed wiring board with fine protrusions.

Embodiment 5 In the fourth embodiment, after laminating the inner layer using a core substrate with a 0.3 mm diameter IVH, a second etching is performed on the outer layer so that the pattern and the minute projections are provided together, and then a necessary portion is drilled. A hole having a diameter of 0.5 mm was opened by processing, and a through hole plating of a copper sulfate type was performed on the opening to form a four-layer printed wiring board with minute protrusions having an IVH and a through hole.

Example 6 In the third example, a double-sided printed wiring board with fine projections was prepared, and on the other hand, iron chloride etching was performed so that a circuit pattern, pads, and fine projections were provided on the copper surface of the copper foil with resin. The resin surface of the copper foil with resin is attached to the micro-projection surface, 170 ° C. × 30 minutes, 40 kg / cm in a laminating press.
Laminated under the conditions of ² , the microprojections pierced the insulating resin layer and connected the microprojections with the circuit patterns, pads, and microprojections of the outer layer to form a 4-layer printed wiring board with patterns, pads, and microprojections. .

Example 7 A printed wiring board having fine projections as shown in FIGS.
A 50 micron deep circuit pattern was formed on a 00 micron conductor layer by first etching with iron chloride to form an etched conductor as shown in FIG. 4, and each layer was laminated via an epoxy-type prepreg to form fine protrusions. 18 pierced the prepreg to form a conductive hole and simultaneously form a strong conductive connection with the upper 50 micron circuit pattern surface. This was repeated five times to form a build-up printed wiring board as shown in FIG.

Embodiment 8 In the seventh embodiment, each layer with fine projections is 25 mm × 2
5mm, 30mm × 30mm, 35mm × 35mm, 4
After punching and forming each cavity 22 having a size of 0 mm × 40 mm by pressing, each layer is laminated via an epoxy type prepreg so that each layer is built-up, and minute projections penetrate the prepreg to form a conductive hole, and at the same time 50 μm of the upper layer is opened. A strong conductive connection with the circuit pattern surface was formed, and this was repeated four times to form a printed wiring board with a cavity as shown in FIG.

Embodiment 9 In the first embodiment, a second etching is performed on the remaining portion of the conductor layer having a thickness of 50 μm and a thickness of 100 μm of the copper foil, and the remaining portion is completely etched. A printed wiring board with the insulating resin surface completely smoothed was formed. 20 and 21 are a completely smooth single-sided plate and a double-sided plate formed similarly.

In the above-described method of manufacturing each pudding wiring board according to the present invention, various conditions are not limited at all.
That is, (1) The material of the conductor layer is not limited as long as it is an electric conductor, and is not limited as long as it is a conductor layer such as copper, nickel, iron, cobalt and alloy conductors of these, and can be widely used. (2) The thickness of the conductor layer can be widely used from 5 microns to 5 mm. (3) The etching resist can be widely used without being limited to a dry film, a liquid resist, a resist ink and the like. In addition to these organic resists, gold, Sn / Pb,
Sn, Ni, their alloys, and other metal resists that resist etching can be used without limitation. As the organic resist, either a positive type or a negative type is applied. (4) The width of the circuit pattern, the interval between circuits, and the conductor thickness of the pattern are all not limited. (5) The semi-curable resin is not limited at all, as long as the semi-curable state is thermosetting or thermoplastic, and the curing reaction proceeds by application of energy such as heat or light. (6) The resin of the rigid substrate is not limited at all, as long as it has electrical insulation properties, regardless of thermosetting properties or thermoplastic properties. (7) The shape of the microprojection is necessary for conductor connection, and is not limited to the examples described in this specification and is not limited at all, as long as the strength capable of forming conduction via the semi-curable insulating resin can be maintained. There is no particular limitation on the location or layer where the microprojections are provided. (8) The material of the coating insulating resin is not particularly limited as long as the coating process can be performed regardless of the method and electrical insulation can be maintained. (9) The substrate laminated on the inner layer is not limited by the presence or absence of a circuit pattern, nor by the thickness or resin material. (10) There are no restrictions on the present invention, such as the pattern of the outer layer, the shape of the pads and the minute projections, and the way of conducting the thickness. (11) There is no limitation on the material and thickness of the cured resin, the presence or absence of the conductor layer, and the like. (12) The method of laminating and electrically connecting conductor layers, insulating resin layers, circuit patterns and pads, microconductor protrusions, core substrates, etc. is achieved with appropriate heating and pressing. There is no limitation as long as it is a method that can be performed, for example, a general method such as a steam press, an oil type heat transfer press, a laminator, etc. , Is not limited at all. (13) The heat radiation layer is not limited at all by the material, shape, layer to be laid, location, number of layers, and the like. (14) Regarding the cavity, its opening shape, location,
There is no limitation on the number, the opening method or the like. (15) There is no restriction on the electronic components mounted on the printed wiring board of the present invention. (16) The method of electrical connection with the electronic component, the method of sealing the electronic component in the cavity or on the substrate, the material, the connection location, and the like are not limited at all.

[0041]

As described above, the present invention is directed to a method of manufacturing a printed wiring board by etching a conductive layer in two steps, wherein the conductive layer has a partial thickness. A first etching step of partially etching the substrate to form a circuit pattern, a laminating step of laminating a circuit forming surface and an insulating resin layer and embedding a circuit pattern in the resin layer, or at least a circuit of the circuit forming surface. A step of forming an insulating resin layer therebetween, and a second etching step of selectively etching a remaining portion of the conductor on the circuit pattern as necessary and selectively etching a desired portion or an entire surface of the remaining thick portion. By using a circuit pattern and a conductor integrally formed on the circuit pattern by a two-step etching method, a fine protrusion can be obtained with high precision and high reliability. The reliability of connection with electronic components using micro projections is significantly improved, there is no circuit pattern shift, no circuit damage occurs, good workability is achieved, the process can be simplified, and the thickness of the material and substrate is reduced. Build-up multilayer printed wiring boards, multilayer printed wiring boards with cavities, pattern-on-pattern boards, pattern-on-pad boards, smooth boards, etc. under a wide range of manufacturing conditions without restrictions, with high density, high precision, high reliability, and low cost There is an effect that it can be obtained.

According to the second aspect of the present invention, since the circuit pattern and the minute projection can be integrally formed by two-step etching, there is an effect that a highly reliable printed wiring board with minute projections can be obtained at low cost.

According to the third aspect of the present invention, since the circuit pattern and the minute projection can be integrally formed by two-step etching, the minute projection penetrates the insulating layer to form a conductive connection between the layers, thereby forming a hole. This eliminates the need for drilling and plating conductive processing between layers, and has the effect that a highly reliable double-sided and multilayer printed wiring board can be obtained at low cost.

According to the fourth aspect of the present invention, since the circuit pattern and the minute projection can be integrally formed by two-step etching, the minute projection penetrates the insulating layer and the conductive connection between the layers is repeated by the number of layers. Accordingly, there is an effect that a build-up multilayer printed wiring board can be obtained with high density, high accuracy, high reliability, and low cost.

According to the fifth and sixth aspects of the present invention, since the circuit pattern and the minute projection can be integrally formed by two-step etching, the minute projection penetrates the insulating layer and the conductive connection between the layers is repeated by the number of layers. By doing so, there is an effect that a multilayer printed wiring board with a cavity can be obtained with high density, high accuracy, high reliability, and low cost.

The invention according to claim 7 has the effect that a pattern-on pattern or a pattern-on-pad printed wiring board can be obtained with high density, high accuracy, high reliability and low cost.

According to the eighth aspect of the present invention, a circuit pattern is formed in a part of the thickness of the conductor layer by two-step etching, and the pattern is laminated and embedded in the insulating resin. There are effects that high accuracy, a thick circuit can be easily formed, and perfect smoothness between the insulating resin surface and the circuit pattern can be obtained at low cost.

According to the ninth aspect of the present invention, the circuit pattern and the minute projection can be integrally formed by two-stage etching.
There is an effect that a core substrate or the like can be easily provided between layers.

According to the tenth aspect of the present invention, since a circuit pattern and minute projections can be integrally formed on the conductor layer by two-step etching, there are various restrictions on the material and processing of other build-up methods and the like. However, there were restrictions such as difficult, but the plating can be easily used together without any restrictions,
This has the effect.

According to the eleventh aspect of the present invention, it is becoming difficult to meet the needs of the world with a conventional printed wiring board, as electronic devices are rapidly becoming faster, more accurate, smaller, and less expensive. On the other hand, the printed wiring board according to the present invention has an advantage that it has a great advantage that can sufficiently meet these needs.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a conductor layer.

FIG. 2 is a longitudinal sectional view in which an etching resist is formed on a conductor layer.

FIG. 3 is a vertical sectional view showing an etching resist on a circuit pattern surface exposed and developed.

FIG. 4 is a longitudinal sectional view in which a circuit pattern is formed by etching and resist peeling.

FIG. 5 is a longitudinal sectional view showing a state in which a semi-curable insulating resin and a rigid resin as required are laid up on a circuit pattern surface.

FIG. 6 is a longitudinal sectional view in which a circuit pattern is laminated and embedded in an insulating resin layer.

FIG. 7 is a longitudinal sectional view in which an etching resist for obtaining minute projections is formed on the remaining thickness portion surface of the conductor layer.

FIG. 8 is a longitudinal sectional view of the first embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of a second embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of a third embodiment of the present invention.

FIG. 11 is a longitudinal sectional view of a fourth embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of the fifth and sixth embodiments of the present invention.

FIG. 13 is a longitudinal sectional view of a lay-up state in a forming process according to a seventh embodiment of the present invention.

FIG. 14 is a longitudinal sectional view showing the shape of a minute projection.

FIG. 15 is a longitudinal sectional view showing the shape of a minute projection.

FIG. 16 is a vertical cross-sectional view of a conductive layer in a forming process according to a seventh embodiment of the present invention.

FIG. 17 is a longitudinal sectional view of a seventh embodiment of the present invention.

FIG. 18 is a longitudinal sectional view of an eighth embodiment of the present invention.

FIG. 19 is a longitudinal sectional view of a ninth embodiment of the present invention.

FIG. 20 is a longitudinal sectional view of a tenth embodiment of the present invention.

FIG. 21 is a longitudinal sectional view of an eleventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive layer 2 Etching resist 3 Circuit pattern 4 Remaining thickness of conductive layer 5 Semi-curable insulating resin layer 6 Rigid insulating resin layer 7 Cured insulating resin layer 8 Etching resist for micro projections 9 Micro projections 10 Resin coating layer 11 Cured insulation Resin layer 12 Double-sided printed wiring board with circuit 13 Inner layer circuit 14 IVH and through hole conduction 15 Upper layer conductor layer 16 Semi-curable insulating resin layer 16 ′ Cavity layer 17 Outer layer circuit pattern 18 Outer pad 19 Outer layer micro projection 20 Insulating resin 21 Heat dissipation Conductive layer 22 Cavity 23 Electronic component 24 Electrical connection 25 Wire bonding 26 Resin sealing

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H05K 3/46 H05K 3/46 NF term (reference) 5E317 AA24 BB01 BB11 CC53 CC60 CD25 GG16 5E339 AB02 AD01 AD03 AD05 BC01 BD02 BD06 BD07 BD11 BE11 CE11 CE12 CE15 5E343 AA02 AA12 BB02 BB15 BB22 BB66 DD55 DD56 DD62 DD76 ER49 GG11 5E346 AA12 AA15 AA43 AA60 BB01 CC08 CC31 DD01 DD32 DD48 EE31 FF24 FF45 GG22 GG28 HH32 HH33

Claims (11)

[Claims] 1. A method for manufacturing a printed wiring board by etching a conductor layer in two steps, comprising: a first etching step of partially etching a partial thickness of the conductor layer to form a circuit pattern; A laminating step of laminating a circuit forming surface and an insulating resin layer and embedding a circuit pattern in the resin layer, or a step of forming an insulating resin layer at least between circuits on the circuit forming surface; A method for manufacturing a printed wiring board, comprising: performing a partial etching process for selectively leaving a desired portion of a thick portion as needed or a second etching step of etching the entire remaining thick portion. 2. The printed wiring board manufactured according to claim 1, wherein the desired portion left integrally with the circuit pattern on the conductor remaining thickness portion by the partial etching of the second etching is a minute projection. A method for producing a printed wiring board with fine projections, characterized by the following. 3. The second conductor layer is integrated with the fine projection forming surface of the printed wiring board with micro projections manufactured in claim 2 via an insulating layer, and the fine projections are made to penetrate the insulating layer. A method for manufacturing a double-sided or multi-layer printed wiring board, comprising: electrically connecting a projecting conductor to a second conductor layer to form an electrical connection; and repeating the conductive formation as necessary a plurality of times. 4. A method for manufacturing a printed wiring board, wherein the multilayer printed wiring board manufactured in claim 3 is a build-up wiring board formed by sequentially repeating conduction formation. 5. A method for manufacturing a multilayer printed wiring board having cavities, wherein one or more layers having cavities are laminated, and electrical conduction between the layers is obtained by the fine projections according to claim 2. A method for manufacturing a multilayer printed wiring board with a cavity, which is characterized by the following. 6. A method of manufacturing a multilayer printed wiring board having a cavity, wherein a cavity is formed in the multilayer printed wiring board manufactured in claim 3 by post-processing. Plate manufacturing method. 7. The printed wiring board manufactured according to claim 1, wherein a desired portion left in the remaining portion of the conductor by the partial etching in the second etching is in a pattern shape or a pad shape. A method for manufacturing a printed wiring board, wherein a pattern-on pattern or a pattern-on pad is formed. 8. The method for manufacturing a smooth printed wiring board according to claim 1, wherein the printed wiring board is smoothened by performing the second etching on the entire surface of the printed wiring board manufactured in claim 1. 9. A method for manufacturing a printed wiring board according to claim 1, wherein a required number of rigid core wiring boards with circuits or adhesive layers are laminated between the layers. 10. A method for manufacturing a printed wiring board, wherein the printed wiring board manufactured according to claim 1 is used together with conduction formation such as through holes, IVH, and BVH. 11. A method for manufacturing a printed wiring board by two-stage etching of a conductor layer, comprising: a first etching step of partially etching a part of the thickness of the conductor layer to form a circuit pattern; A laminating step of laminating a circuit forming surface and an insulating resin layer and embedding a circuit pattern in the resin layer, or a step of forming an insulating resin layer at least between circuits on the circuit forming surface; A printed wiring board obtained by performing a second etching step of partially etching a thick portion to leave a desired portion as necessary or etching the entire remaining thick portion.