KR100742679B1 - Printed wiring board and production thereof - Google Patents

Abstract

The insulating film 31, 41 of the laminated board for multi-layering is extended to the cable portion B of the base substrate so that not only the constituent material of the substrate can be made thin, but also the structure can be further thinned. The printed wiring board which can remove a coverlay, and its manufacturing method are provided by protective-covering the conductor layers 12 and 13 of the cable part B by the extension part 31B, 41B of (31, 41).

Printed, Wiring Boards, Rigid-Flex, Extension, Laminated, Polyimide

Description

Printed wiring board and its manufacturing method {PRINTED WIRING BOARD AND PRODUCTION THEREOF}

1 is a cross-sectional view showing an embodiment in which the printed wiring board according to the present invention is applied to a rigid-flex six-layer substrate.

2 (a) and 2 (b) are process diagrams showing an example (manufacturing of a base substrate) of a manufacturing process of a rigid-flex six-layer substrate according to an embodiment of the present invention.

3 (a) to 3 (e) are process diagrams showing an example of the manufacturing process of the rigid-flex six-layer substrate according to the embodiment of the present invention (manufacturing a laminated plate used for upper multilayering).

4 (a) to 4 (e) are process charts showing an example of the manufacturing process of the rigid-flex six-layer substrate according to the embodiment of the present invention (manufacturing a laminated plate used for lower multilayering).

5 (a) and 5 (b) are process diagrams showing an example (lamination) of a manufacturing process of a rigid-flex six-layer substrate according to an embodiment of the present invention.

6 (c) and 6 (d) are process diagrams showing an example (lamination) of the manufacturing process of the rigid-flex six-layer substrate according to the embodiment of the present invention.

7 (e) and 7 (f) are process charts showing an example (lamination) of a manufacturing process of a rigid-flex six-layer substrate according to an embodiment of the present invention.

8 is an exemplary cross-sectional view of a conventional rigid-flex six-layer substrate.

* Explanation of the sign

10: inner layer CCL, 11, 31, 41: polyimide film,

12, 13, 32, 33, 42, 43: conductor pattern, 14, 15, 44, 45: copper foil,

19, 39, 49 double-sided copper clad laminates, 21, 22: interlayer adhesive sheet;

23, 24: prepreg, 25, 26: plated through hole,

27, 28: surface vias, 30, 40 outer layer CCL,

38, 48: laminate, 51, 52 permanent resist layer,

61, 62 interlayer through holes, 63, 64 surface vias,

65, 66 copper plating layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board and a method for manufacturing the same, and more particularly, to a printed wiring board having a multilayered portion in a partial region of a base substrate such as a rigid-flex substrate and the like and a method for manufacturing the same.

As a kind of printed wiring board used for an electronic device, the rigid-flex board | substrate of the following structures is known.

That is, a rigid-flex board | substrate has a base substrate which has a conductor layer, such as copper foil, on one surface of the insulating base film which has flexibility like polyimide, etc. On the surface, in order to multilayer the partial region, a laminated plate having a conductor layer is laminated on at least one surface of the insulating film, and a rigid multilayer part made of the conductor layer of the substrate substrate and the conductor layer of the laminated plate is formed, and the The flexible cable part for conduction connection which consists of the said conductor layers of a base material board | substrate is formed.

Such a rigid-flex board is a Japanese CMK homepage [search on October 1, 16, 2016] Internet URL: http: //www.cmk-corp.com/html/product/prod_rf_idx.html , http: //www.cmk -corp.com/pdf/products/RigidFlex0306.pdf (Non-Patent Document 1) and Japan Mektron Homepage (searched on October 1, 2016) Internet URL: http: //www.mektron.co.jp/fb/ index.htm1 , http://www.mektron.co.jp/fbb/index.html (Non-Patent Document 2), and the like.

A specific example (six layers) of a conventional rigid-flex substrate will be described with reference to FIG. 8.

As shown in FIG. 8, the conventional rigid-flex 6-layer board | substrate is an inner layer CCL (Copper Clad Laminate, copper clad laminated board) for FPC as a base substrate in the center (center of a lamination direction) of sectional drawing; 100], that is, a double-sided copper clad inner layer CCL (0000) having conductor patterns 102 and 103 made of copper foil on both sides of the polyimide film 101 is disposed, and CL (coverlay) 110 on the entire surface of both sides thereof. 120 is arranged. CL (110, 120) has adhesive layers (112, 122) on one surface of cover films (111, 121), such as polyimide, and the surface of CCL (l00) by respective adhesive layers (112, 122). It is joined.

In addition, in the partial regions (both left and right in the cross-sectional view) on the outer side (outer layer side), the outer layer CCL 140, 150 having a double-sided copper sheet through the interlayer adhesive sheets (interlayer adhesives 131, 132) and the prepregs 133, 134. ) Is laminated. The outer layer CCLs 140 and 150 are formed with conductor patterns 142, 143, 152 and 153 made of copper foil on both surfaces of the insulating films 141 and 151, respectively.

In this way, the multilayer part A by the inner layer CCL (110), the outer layer CCLs 140 and 150, and the flexible cable part B for conduction connection by the inner layer CCL (110) are comprised.

In the multilayer portion A, interlayer conduction plating through holes l35 and 136 are formed. In the outermost layer, permanent resist layers (insulation layers) 137 and 138 for circuit protection are formed.

The manufacturing process of this rigid-flex 6-layer board | substrate is as follows, for example.

(1) As a base substrate arranged in the center, circuits are formed (formation of conductor patterns 102 and 103) on both surfaces of the inner layer CCL (00) for FPC, and CL (ll0, 120) is bonded to both surfaces thereof.

(2) In the outer layer CCLs 140 and 150, a circuit (conductor patterns 142 and 152) located on the inner layer CCL (l00) side is formed, and the outer layer CCLs 140 and 150 are interlayer adhesive sheets 131 132 and the prepregs 133 and 134 to bond with the inner layer CCL 100 formed in step (1). In this way, the multilayer part A is formed.

(3) A through hole is made in order to mutually conduct the interlayer circuit of the multilayer part A, and copper plating is performed on the copper foil surface and the inside of the through hole, and the plating through holes 135 and 136 are formed.

(4) The circuits of the outermost layers of the outer layers CCL (140, 150) are formed (formation of the conductor patterns 143, 153), and a permanent resist layer (solder resist layers; 137, 138) is formed to be rigid- Complete the Flex 6 layer substrate.

In the case of a rigid-flex six-layer substrate, the prepregs 133 and 134 may be omitted and stacked only through the interlayer adhesive sheets 131 and 132. In the case of the FPC multilayer substrate, the prepregs 133 and 134 are omitted, and the same FPCs as the inner layer CCL 100 are used as the outer layer CCLs 140 and 150.

This kind of multilayer substrate has a special advantage by forming the multilayer portion A and the cable portion B integrally and making the cable portion B flexible.

Although these multilayer board | substrates are laminated | stacked with an interlayer adhesive agent, a prepreg, etc. as demonstrated in the said process, it is necessary to suppress the leaching of the adhesive agent in the boundary part C of the multilayer part A and the cable part B. . It is preferable that an interlayer adhesive agent needs to ensure circuit filling property in the multilayer part A, and it is preferable that melt viscosity at the time of uncuring is low. However, if the melt viscosity of the interlayer adhesive is too low, the amount of leaching at the boundary portion C between the multilayer portion A and the cable portion B is large at the time of lamination, thereby reducing the flexibility of the cable portion B. There is a case.

In order to solve such a problem, a method of preventing this by adjusting the melt viscosity of the adhesive or the prepreg material or combining the cushioning material used at the time of bonding so as to secure the circuit filling property and to suppress the resin flow is common. It is done. In addition to these methods, there is also a proposal to prevent the outflow of resin to the cable part by providing a dummy pattern at the boundary part or by placing a dam material for preventing the resin flow at the boundary part. Such a proposal is described in Japanese Patent Application Laid-Open No. 2001-156445 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2001-185854 (Patent Document 2).

However, the prevention of resin leakage from the multi-layered part to the cable part requires a different process from the usual case in which a dummy pattern for adjusting the viscosity of the resin or a dam material is provided. There was a problem.

On the other hand, with the miniaturization and thinning of electronic devices, the printed circuit board mounted on the electronic device is required to be further thinned, so that there is a limit in the conventional multilayer substrate structure.

In order to thin a board | substrate with a conventional structure, it is necessary to thin the material to be used. For example, the following materials are used for a multilayer board | substrate.

(1) CCL (polyimide film and circuit copper foil)

Polyimide films are commonly used materials having a thickness of 25 μm (1 mil). As a thin substrate, 12.5 μm (1/2 mil) is also used. Copper foil is available in 35μm (1oz) as standard, 18μm (1 / 2oz), 12μm (1 / 3oz) and 9μm (1 / 4oz). For example, if the polyimide film is 1/2 mil and the copper foil is 1/4 oz, CCL with a total thickness of 21.5 μm is formed, but the thin copper foil is expensive, the production of CCL is difficult, and the material cost is high. Moreover, since it is thin, it is difficult to handle and defects by folding, wrinkles, etc. are easy to produce by hand.

(2) CL (polyimide film and adhesive layer)

Like CCL, polyimide films are commonly used with 1 mil of material, but 1/2 mil of material is also used as a thin substrate. An adhesive agent can be processed to arbitrary thickness and needs to be thicker than a circuit copper foil in order to fill between circuits.

(3) Glass fiber reinforced epoxy resin board (GE board)

Although there exists a thin base material of about 60 micrometers, since glass fiber is clamped in the center, there exists a limit to thinning.

(4) Adhesives for bonding between layers

Similar to the adhesive for CL, it can be processed to an arbitrary thickness and needs to be thicker than the circuit copper foil in order to fill between circuits.

(5) Copper plating to connect between layers

Since connection reliability must be secured, there is a limit in thinning. The limit thickness also depends on the material, thickness of the substrate and the quality of the holes. In general, the thinner the substrate, the thinner the plating thickness can be.

(6) permanent resist layer of surface layer

For the protection of the surface layer circuit, a certain thickness is required, depending on the circuit thickness.

However, any material required a certain thickness or more in order to secure productivity, cost, and performance, and there was a limitation in thinning.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the structure and to further reduce the thickness of the printed circuit board, and to prevent the leakage of resin from the multilayer to the cable. It is to provide a manufacturing method.

The printed wiring board according to the present invention has a conductor layer on at least one surface of the insulating film on the side of the conductor layer side of the base substrate having the conductor layer on at least one surface of the insulating base film in order to multilayer the partial regions of the base substrate. Stacking a laminated plate, the multilayered portion including the conductor layer of the base substrate and the conductor layer of the laminate; And a conductive connection cable portion formed of the conductor layer of the base substrate, wherein the insulating film of the laminate for multilayering extends to the cable portion of the base substrate, and the extension portion of the insulating film is It has the function of the cover film which protective-covers the said conductor layer of a cable part.

In the printed wiring board which concerns on this invention, it is preferable that the said insulating film of the said laminated board is joined to the surface of the conductor layer side of the said base board by an adhesive sheet in the said cable part.

In the printed wiring board according to the present invention, it is preferable that both of the base film of the base substrate and the insulating film of the laminated board are composed of a flexible resin film.

It is preferable that the prepreg is laminated | stacked on the said multilayer part in the printed wiring board by this invention.

The method for manufacturing a printed wiring board according to the present invention is a conductor on at least one surface of an insulating film in order to multilayer the partial region of the base substrate on the surface of the base layer side of the base substrate having a conductor layer on at least one surface of the insulating base film. Stacking a laminated plate having layers to form a multi-layered portion consisting of the conductor layer of the base substrate and the conductor layer of the laminate; In the manufacturing process of the printed wiring board which includes the laminated hardening process of forming parts other than the said multilayer part by the conductive connection cable part which consists of the said conductor layer of the said base substrate, The said insulating film of the said laminated board is the said of the said base substrate. It extends to a cable part, the extension part of the said insulating film is joined with the said cable part in the said lamination | hardening hardening process, and the said extension part protective-coats the said conductor layer of the said cable part.

The novel features of the invention are set forth in the claims. However, the invention itself and other features and effects can be easily understood from the detailed description of specific embodiments with reference to the accompanying drawings.

An embodiment in which the printed wiring board according to the present invention is applied to a rigid-flex six-layer substrate will be described with reference to FIG. 1.

As shown in Fig. 1, the rigid-flex six-layer substrate of the present embodiment has an inner layer CCL (copper laminate) 10 for FPC as a base substrate at the center (center in the stacking direction) of the cross section. Conductor patterns 12 and 13 are formed with copper foil on both surfaces of the polyimide film (polyimide base material) 11 which is this flexible layer CCL (10).

In the partial regions (both left and right in the cross-sectional view) of both surfaces of the inner layer CCL10, the outer layer CCL 30 of the double-sided copper sheet is formed through the interlayer adhesive sheets 21 and 22 by epoxy adhesive and the epoxy prepregs 23 and 24. 40 are laminated.

Outer layer CCL (30, 40) is a copper clad laminated board for multilayering, respectively, and the conductor pattern (32, 33, 42) of copper foil on both surfaces of the polyimide film (polyimide base material; 31, 41) which is an insulating and flexible resin film, respectively. , 43).

In this way, the multilayered part A which consists of inner layer CCL10, the outer layer CCLs 30 and 40, and the flexible cable part B for conductive connection which consists of inner layer CCL10 are formed.

In the multilayer part A, plating through-holes 25 and 26 and surface vias 27 and 28 for interlayer conduction are formed. In the outermost layer, permanent resist layers (insulating layers) 51 and 52 for circuit protection are formed.

The polyimide films 31 and 41 of the outer layer CCLs 30 and 40 extend up to the cable portion B of the inner layer CCL 10 made of a base substrate, and the cable corresponding portions of the polyimide films 31 and 41. (Extension part) 31B, 41B is joined to the surface of the cable correspondence part 21B, 22B of the interlayer adhesive sheet 21, 22 provided in the both surfaces whole surface of the inner layer CCL10.

In this way, the cable correspondence part (extension part 31B, 41B) of the polyimide film 31, 41 of the outer layer CCL (30, 40) forms the conductor pattern (conductor layer; 12, 13) of the cable part B. It has the function of the cover film which protective-covers.

In the rigid-flex board | substrate of such a structure, CL (coverlay) for protective coating of the conductor pattern of the cable part B is unnecessary. That is, in the conventional rigid-flex substrate shown in FIG. 8, since the CLs 110 and 120 stacked in the same manner in the multilayered portion A and the cable portion B can be omitted, the multilayered portion A can be omitted. I can thin it.

Compared with the conventional example, when the CL of the polyimide film 25 micrometers and the adhesive bond layer 25 micrometers is used conventionally, in this Example, the multilayer part A can be made thin by 100 micrometers in total on both surfaces. In addition, when CL is not required, the material cost can be naturally saved.

In addition, since the interlayer adhesive sheets 21 and 22 are both disposed inside the outer layers CCL 30 and 40, they are not exposed to the outside of the substrate. Therefore, under normal lamination conditions, leaching at the boundary portion C of the interlayer adhesive sheets 21 and 22 can be suppressed, thereby improving the flexibility of the boundary portion.

The prepregs 23 and 24 are used when the mechanical strength of the multilayer part A is needed (rigidization), and can be made thin as needed. It may also be omitted. Or the interlayer adhesive sheet for removing the interlayer adhesive sheets 21 and 22 of the multilayer part A, leaving only the prepregs 23 and 24, and sticking the polyimide films 31 and 41 only to the cable part B ( 21 and 22 (parts 21B and 22B only) may be provided.

Below, an example of the manufacturing process of the rigid-flex 6-layer substrate of a present Example is demonstrated with reference to FIGS.

(Manufacture of Base Board)

As shown in Fig. 2A, a double-sided copper clad laminate 19 having copper foils 14 and 15 on both sides of the polyimide film 11 is used as a starting material, and as shown in Fig. 2B. The copper foils 14 and 15 are etched to form the conductor patterns 12 and 13 to complete the inner layer CCL10 as a base substrate.

(Production of the upper multilayered laminate)

As shown in Fig. 3A, a double-sided copper clad laminate 39 having copper foils 34 and 35 on both sides of the polyimide film 31 is used as a starting material, and as shown in Fig. 3B. The lower copper foil 35 is etched to form a conductor pattern 33. The double-sided copper-clad laminate 39 has the same size as the double-sided copper-clad laminate 19 for the base substrate, and the conductor pattern 33 of the double-sided copper-clad laminate 39 is formed only in the multilayered corresponding portion Aa, and the cable-compatible portion Ba ), All copper foil 35 is removed.

And as shown in FIG.3 (c), the prepreg of the magnitude | size corresponding to the magnitude | size of the multilayered corresponding | corresponding part Aa on the conductor pattern 33 side of the multilayered corresponding | correspondence part Aa of the double-sided copper clad laminated board 39 is shown. (23) is laminated. The prepreg 23 exists only in the multilayer correspondence part Aa.

Next, as shown in FIGS. 3D and 3E, the prepreg 23 side of the double-sided copper clad laminate 39 has the same size as that of the double-sided copper clad laminate 39, that is, the double-sided copper sheet for the base substrate. The interlayer adhesive sheet 21 having the same size as the laminated plate 19 is laminated. And the interlayer adhesive sheet 21 may be laminated on the conductor pattern 12 side of the inner layer CCL10.

(Manufacture of Laminated Plates for Bottom Multilayering)

As shown in Fig. 4A, a double-sided copper clad laminate 49 having copper foils 44 and 45 on both sides of the polyimide film 41 is used as a starting material, and as shown in Fig. 4B. The upper copper foil 44 is etched to form a conductor pattern 42. The double-sided copper-clad laminate 49 also has the same size as the double-sided copper-clad laminate 19 for the base substrate, and the conductor pattern 42 of the double-sided copper-clad laminate 49 is formed only in the multilayered corresponding portion Ab, and the cable-compatible portion Bb. ) All copper foils 44) are removed.

And as shown to Fig.4 (c), the prepreg of the magnitude | size corresponding to the magnitude | size of the multilayered corresponding | corresponding part Ab is on the conductor pattern 42 side of the multilayered corresponding | corresponding part Ab of the double-sided copper clad laminated board 49. As shown to FIG. (24) is laminated. The prepreg 24 is present only in the multilayered counterpart Ab. Incidentally, the multilayered counterparts Aa and Ab have the same size.

Next, as shown in FIGS. 4D and 4E, the prepreg 24 side of the double-sided copper clad laminate 49 has the same size as the double-sided copper clad laminate 49, that is, the double-sided copper clad laminate for the base substrate. The interlayer adhesive sheet 22 having the same size as that of (19) is laminated. And the interlayer adhesive sheet 22 may be laminated on the conductor pattern 13 side of the inner layer CCL10.

(Stacked)

As shown in Fig. 5A, the laminated plate 38 of Fig. 3E is placed above the inner layer CCL10, and the laminated plate of Fig. 4E is placed below the inner layer CCL10. Each of 48 is placed, and as shown in FIG. 5B, these are collectively laminated and cured. This lamination | hardening hardening heats and presses the laminated body of the laminated board 38, the inner layer CCL 10, and the laminated board 48 using a hot press machine, and the interlayer adhesive sheets 21 and 22 and the prepregs 23 and 24. ) Is hardened to the C stage state.

In this way, the multilayer connection part A which consists of an inner layer CCL (10), the laminated boards 38 and 48, and the flexible cable part B for conductive connection which consists of an inner layer CCL10 is comprised.

By this lamination hardening, the cable correspondence part 31B of the polyimide film 31 of the upper laminated board 38 is an inner layer by the cable correspondence part 21B of the interlayer adhesive sheet 21 in the cable part B part. It is strongly bonded to the upper surface of CCL10. Moreover, the polyimide film 41 (cable correspondence part 41B) of the lower laminated board 48 is an inner layer CCL (at the cable part B part by the cable correspondence part 22B of the interlayer adhesive sheet 22). Strongly bonded to the lower surface of 10).

Subsequently, as shown in FIG.6 (c), the interlayer conduction holes 61 and 62 which penetrate the multilayer part A are formed. If necessary, holes 63 and 64 for partial interlayer conduction are formed.

Subsequently, as shown in Fig. 6D, copper plating causes interlayer conduction holes 61 and 62 and surface via vias 63 and 64 to be electrically intercalated by the copper plating layers 65 and 66. .

Next, as shown in FIG. 7E, the copper foil 34 and the copper plating layer 65 of the upper laminated plate 38 are etched to form the uppermost outermost conductor pattern 32, and the lower laminated plate. The copper foil 45 of 38 and the copper plating layer 66 are etched, and the outermost layer conductor pattern 42 below is formed. At the same time, the plated through holes 25 and 26 for interlayer conduction and the surface vias 27 and 28 in the multilayer portion A are completed.

The copper foil 34 and the copper plating layer 65 of the upper laminated board 38 and the copper foil 45 and the copper plating layer 66 of the lower laminated board 38 are all removed by the cable part B. As shown in FIG. In this way, the polyimide films 31 and 41 remain | survive in the cable part B, and the polyimide films 31 and 41 become the cover film which protective-covers the cable part B, and the cable part B Flexibility is ensured.

Next, as shown in FIG.7 (f), the outermost layer surface is coat | covered with the permanent resist layers 51 and 52, and surface treatment required for an exposed part is performed, and a rigid-flex 6 layer board | substrate is completed.

The rigid-flex substrate manufactured in such a configuration can be made as thin as CL × 2 sheets in the case of the cable part B double-sided structure, and the leaching at the boundary C of the interlayer adhesive sheets 21 and 22 is prevented. Since it can suppress, flexibility in a boundary part improves.

EXAMPLE

The characteristic of the board | substrate manufactured as follows was evaluated. Characteristic evaluation was performed about the leaching amount of the adhesive agent in a cable part, flexible interlayer connection reliability, and migration resistance.

Evaluation of flexibility performed the flex resistance test (JIS C5016). The number of times of bending and disconnection at the boundary between the multi-layer part and the cable part was measured at a radius of radius of 3 mm. This is a relative evaluation with the number of Comparative Examples 2 as 1. The interlayer connection reliability evaluation was conducted by a vapor phase heat shock test (-25 ° C., 125 ° C./60 min cycle × l000 times). The conductor resistance was measured by measuring the conductor resistance of the through-through part. Evaluation of migration resistance is insulation resistance measurement by comb electrode pattern (circuit total length 2m) of L / S = 100μm / 100μm at high temperature, high humidity DC voltage application test (85 degrees Celsius / 85RH% / DC50V X 1000 hours) It was 10 M (ohm) or more.

(Example 1)

Structure: Rigid-Flex 6 Layer Substrate Shown in FIG.

Material composition used

Permanent resist layer: alkali developing dry film type solder resist (38 μm thick)

Outer layer CCL: electrolytic copper foil (12 μm thick), polyimide substrate (25 μm thick)

Prepreg: epoxy-based prepreg material (60μm thick)

Interlayer adhesive sheet: epoxy adhesive (25 μm thick)

Inner layer CCL: rolled copper foil (12 μm thick), polyimide substrate (25 μm thick)

Interlayer connection: copper plating (25 μm thick)

(Example 2)

Structure: FPC 6-layer substrate excluding prepreg layer in rigid-flex 6-layer substrate shown in FIG.

Material composition used

Permanent resist layer: same as Example 1

Outer layer CCL: same as Example 1

Interlayer adhesive sheet: epoxy adhesive (40 μm thick)

Inner layer CCL: same as Example 1

Interlayer connection: same as Example 1

(Example 3)

Structure: Rigid-Flex 6-layer substrate in the rigid-flex 6-layer substrate shown in FIG.

Permanent resist layer: same as Example 1

Outer layer CCL: same as Example 1

Interlayer adhesive sheet: same as Example 1

Inner layer CCL: same as Example 1

Prepreg: same as Example 1

Interlayer connection: same as Example 1

(Comparative Example 1): Rigid-Flex 6-Layer Substrate Shown in FIG. 8

Material composition used

Permanent resist layer: same as Example 1

Outer layer CCL: same as Example 1

Prepreg: same as Example 1

Interlayer adhesive sheet: same as Example 1

CL: epoxy adhesive (25 μm thick), polyimide substrate (25 μm thick)

Inner layer CCL: same as Example 1

Interlayer connection: same as Example 1

Comparative Example 2 FPC 6-layer Substrate Excluding Prepreg Layer

Material composition used

Permanent resist layer: same as Example 1

Outer layer CCL: same as Example 1

Interlayer adhesive sheet: same as Example 1

CL: same as Example 1

Inner layer CCL: same as Example 1

Interlayer connection: same as Example 1

Table 1 shows the evaluation results of Examples 1 to 3 and Comparative Examples 1 and 2.

TABLE 1

Board thickness Adhesive leaching amount to cable part Flexibility Interlayer connection reliability Migration resistance Example 1 420㎛ none 1.4 ○ ○ Example 2 330㎛ none 1.8 ○ ○ Example 3 370 ㎛ none 1.3 ○ ○ Comparative Example 1 520㎛ About 1mm 0.5 ○ ○ Comparative Example 2 400 μm 0.3 mm One ○ ○

As can be clearly seen in Table 1, in Examples 1 to 3, the substrate thickness (thickness of the multi-layered part) is thinner than Comparative Examples 1 and 2, there is no leaching of the adhesive to the cable part, and the flexibility at the boundary between the multi-layered part and the cable part. (Flexibility) has been improved. Interlayer connection reliability and migration resistance obtained the same result in Examples 1-3 and Comparative Examples 1 and 2.

In the printed wiring board according to the present invention, in the printed wiring board in which the multilayered portion and the cable portion are formed integrally, the insulating film constituting the multilayered portion is extended to be a protective film of the cable portion, and a cover lay of the protective coating of the cable portion is not necessary. It is possible to reduce the material cost as much as the cover lay, to facilitate the thinning of the substrate, and to prevent the resin from leaking from the multilayer to the cable.

Claims (5)

The base substrate on which a laminated plate having a conductor layer is laminated on at least one surface of the insulating film on at least one surface of the insulating film in order to multilayer the partial region of the base substrate on the side of the conductor layer side of the base substrate having the conductor layer on at least one surface of the insulating base film. A multilayer portion consisting of the conductor layer of and the conductor layer of the laminate; And Conductive connection cable part consisting of said conductor layer of said base substrate In the printed wiring board comprising: And the insulating film of the laminate for multilayering extends to the cable portion of the base substrate, and the extension portion of the insulating film has the function of a cover film for protective coating the conductor layer of the cable portion. The method of claim 1, The said insulating film of the said laminated board is bonded by the adhesive sheet in the said cable part to the surface of the conductor layer side of the said base board, The printed wiring board characterized by the above-mentioned. The method according to claim 1 or 2, Both the said base film of the said base substrate and the said insulating film of the said laminated board are comprised from the flexible resin film, The printed wiring board characterized by the above-mentioned. The method of claim 3, Prepreg is laminated | stacked on the said multilayer part, The printed wiring board characterized by the above-mentioned. On the side of the conductor layer side of the base substrate having the conductor layer on at least one surface of the insulating base film, a laminated plate having the conductor layer is laminated on at least one surface of the insulating film in order to multilayer the partial region of the base substrate, and the base substrate A multilayer curing step of forming a multilayered portion comprising the conductor layer and the conductor layer of the laminated plate, and forming a portion other than the multilayered portion into a conductive connection cable portion formed of the conductor layer of the base substrate, Extending the insulating film of the laminated plate to the cable portion of the base substrate, bonding the extension portion of the insulating film to the cable portion in the lamination curing process, and protecting the conductor layer of the cable portion with the extension portion. The manufacturing method of the printed wiring board characterized by the above-mentioned.

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