JP2012234937A - Rigid flexible printed circuit board and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rigid flexible printed circuit board which has a blind via hole that reaches a wiring pattern of a multilayer flexible wiring board from a build-up layer finely formed therein.SOLUTION: A method for manufacturing the rigid flexible printed circuit board includes the steps of: forming a metal pillar intermediate land on the surface of a support film formed over a region of a rigid part and flexible part; forming an inner layer flexible wiring board having a coverlay film laminated on both surfaces of the support film; forming a hole which reaches the metal pillar intermediate land from the both surfaces of the inner layer flexible wiring board; forming a metal plated pillar which is formed integrally with the metal pillar intermediate land by filling the hole with metal plating; forming an alignment mark and a reinforcing metal pattern at a boundary portion of the flexible part and rigid part on the surface of the inner layer flexible wiring board; laminating build-up layers in a region of the rigid part of the inner layer flexible wiring board; adjusting a position to the alignment mark, and vertically forming the side face of the end part of the build-up layer on the reinforcing metal pattern.

Description

  The present invention relates to a rigid flexible printed wiring board comprising a flexible wiring board and a rigid wiring board, and a method for manufacturing the same.

  In recent years, rigid flexible printed wiring boards have been used in portable electronic devices such as folding mobile phones. As such a printed wiring board, the techniques of Patent Document 1 and Patent Document 2 are known. In particular, in Patent Document 2, a rigid rigid part having no flexibility is connected via a flexible flexible part. In the rigid part, the wiring pattern of the flexible wiring board and the wiring pattern of the rigid wiring board are connected to the via fill. A technique for electrically connecting via metal columns by plating is disclosed.

Japanese Patent Laid-Open No. 3-141693 International Publication WO2008 / 050399

  However, in the technique of Patent Document 1, a curable resin is coated with a resin composition mixed with a release agent such as a silicon release agent or a fluorine release agent, and the surface is releasable. A peeling portion formed by applying a resin component that is not compatible with the adhesive tape or the resin component of the prepreg is provided on the rigid flexible printed wiring board. Thereby, since the flexible part is formed by peeling the resin layer formed on the peeled part from the peeled part, there is a problem that the peeled part remains in the flexible part. That is, since the peeled portion remains on the rigid flexible printed wiring board, there is a possibility that the surface insulation of the flexible portion due to the material of the peeled portion may be adversely affected and the electrical characteristics of other substrates may be adversely affected. There was a high problem.

  On the other hand, in the rigid flexible printed wiring board of Patent Document 2, a rigid core substrate having the same thickness is juxtaposed on both sides of a multilayer flexible wiring board on which a wiring pattern is formed, and a part of the core substrate and the multilayer flexible wiring board are arranged. An inner layer flexible wiring board in which an insulating layer of a low flow resin sheet that hardly generates resin flow is laminated on both sides and a copper film is formed on the entire surface of the core substrate and the multilayer flexible wiring board has been manufactured. Then, a build-up layer composed of an insulating layer, a wiring pattern, and a blind via hole is laminated on both surfaces of the inner-layer flexible wiring board, and a processing laser beam is applied to both sides of a part of the multilayer flexible wiring board from the surface of the build-up layer. Irradiation was performed until the copper film at the end of the insulating layer was reached to form a groove. Then, the rigid flexible printed wiring board which formed the flexible part by peeling the buildup layer of the both sides of a multilayer flexible wiring board from the position of the groove | channel was manufactured.

  However, in the technique of Patent Document 2, the insulating layer formed on both sides of a part of the multilayer flexible wiring board is a state in which a desired shape is extracted in advance from a low-flow resin sheet that hardly generates resin flow. This causes the following problems.

  (Problem 1) Since the desired portion where the flexible wiring board is exposed has a recessed shape, pressure is applied uniformly during the heat and pressure molding in the lamination press, and the bonding resin does not flow into the exposed portion of the flexible wiring board. Thus, it is necessary to use a cushioning material having sufficient followability and having a separation formation.

  (Problem 2) Even when the above cushioning material is used, the gap is limited to about 150 μm, and the build-up layer that can be formed on the multilayer flexible wiring board has a problem that the build-up up to two layers is the limit. .

  (Problem 3) Since a low-flow resin sheet is used for the insulating resin of the build layer, followability between inner layer circuit patterns is poor, and laminated voids are likely to occur. Further, since the unevenness of the inner layer circuit pattern affects the surface of the laminate, there is a problem that it is difficult to form a fine pattern (for example, less than L / S = 75/75) on the inner layer circuit pattern.

  (Problem 4) Moreover, a wiring pattern cannot be formed on the surface of the multilayer flexible wiring board exposed under the formed resin layer. Therefore, the height of the blind via hole reaching the wiring pattern of the multilayer flexible wiring board from the build-up layer formed on the multilayer flexible wiring board becomes high, and the blind via hole cannot be formed finely. There has been a problem that becomes an obstacle to increasing the density of patterns.

  The present invention solves the above-described problems, enables a multilayer build-up layer that can be formed on a multilayer flexible wiring board to be formed in multiple layers, and provides a blind via hole that connects the multilayer flexible wiring board and the build-up layer. The present invention provides a rigid flexible printed wiring board in which a wiring pattern is formed at a high density by reducing the height, and a manufacturing method thereof.

  In order to solve the above-described problems, the present invention provides a rigid flexible printed wiring board in which a rigid rigid portion is connected via a flexible flexible portion, and the support film extends over the region of the rigid portion and the flexible portion. A metal pillar intermediate land is formed on the surface of the support film, and an inner layer flexible wiring board is formed by laminating coverlay films on both sides of the support film, and a hole reaching the metal pillar intermediate land from both surfaces of the inner layer flexible wiring board is formed. And having a metal plating column formed integrally with the metal column intermediate land by filling the hole with metal plating, and on the surface of the inner layer flexible wiring board, an alignment mark, the flexible portion and the rigid portion A reinforcing metal pattern is formed at the boundary portion of the inner layer, and a buildup layer is laminated on the region of the rigid portion of the inner layer flexible wiring board. Are combined is positioned in alignment marks, a rigid flexible printed wiring board side of the end of the build-up layer is characterized in that it is vertically formed on the metal reinforcement pattern.

  Further, the present invention is the above-mentioned rigid flexible printed wiring board, wherein the metal plating column portion on one side of the metal column intermediate land has a metal column land in the outermost layer portion, and a first floor in the intermediate portion. A rigid flexible printed wiring board, characterized in that the second floor high via hole has a land, and the diameter of the second floor high via hole on the outer layer side of the first floor land is larger than the diameter on the inner layer side.

  The present invention also relates to a method for manufacturing a rigid flexible printed wiring board in which a rigid rigid portion is connected via a flexible flexible portion, the support film extending over the rigid portion region and the flexible portion region. Forming a metal pillar intermediate land in the region of the rigid portion on at least one surface, manufacturing an inner-layer flexible wiring board by laminating a coverlay film with copper foil on both surfaces of the support film, and the inner layer Forming a hole reaching the metal pillar intermediate land by irradiating laser light for drilling from both sides of the flexible wiring board, and filling the hole with metal plating, and forming the hole integrally with the metal pillar intermediate land A step of forming a metal plating column, an alignment mark on the surface of the inner layer flexible wiring board, the flexible portion and the rigid portion; A step of forming a reinforcing metal pattern at a boundary portion, a step of laminating a build-up layer in the region of the rigid portion of the inner layer flexible wiring board, and a position of the flexible portion and the rigid in alignment with the alignment mark Forming a groove that exposes the side surface of the end of the build-up layer vertically on the reinforcing metal pattern by irradiating the build-up layer at the boundary portion with the processing laser beam; and the groove It is a manufacturing method of the rigid flexible printed wiring board characterized by having the process of isolate | separating and removing the said buildup layer and said thin peeling film on a flexible part on the boundary.

  Further, the present invention is a method of manufacturing the above rigid flexible printed wiring board, wherein in the step of forming the metal pillar intermediate land, a first-floor land facing the metal pillar intermediate land and having a hole in the center is provided. Forming the hole reaching the metal column intermediate land, and forming the hole from the surface far from the metal column intermediate land toward the metal column intermediate land via the first floor land. , The peripheral portion of the laser beam for drilling is blocked by the first-floor land, and only the laser beam for drilling that has passed through the holes reaches the metal column intermediate land. A method for manufacturing a rigid flexible printed wiring board, wherein a step is formed in a diameter of a hole reaching an intermediate land.

  According to the present invention, since the thin release film 31 is peeled off and removed from the flexible portion 102 of the rigid flexible printed wiring board 10, the electrical characteristics of the surface of the flexible portion 102 are not affected by the material of the thin release film 31.

  In the present invention, a thin coverlay film 20 is laminated on the flexible wiring board 1a having a multilayer wiring, and the height of the blind via hole formed by being embedded in the layer of the coverlay film 20 is lowered. By reducing the diameter, the wiring pattern on the coverlay film 20 can be formed with high density.

  In particular, according to the present invention, a reinforcing metal pattern is formed at the boundary between the alignment mark, the flexible portion, and the rigid portion on the outer layer side surface of the coverlay film, and laser processing is performed by aligning the alignment mark with the alignment mark. Then, a groove that overlaps the position of the end of the thin release film on the reinforcing metal pattern is formed at an accurate position. Therefore, the groove is vertically formed on the reinforcing metal pattern at an accurate position. On the other hand, by aligning the position with the alignment mark, the thin release film is formed by accurately aligning the end portion with the groove forming position. Thereby, the groove | channel formed by laser processing can be formed in position so that it may apply | hang | start to the edge part of a thin peeling film correctly. Thereby, there is an effect that the thin release film on the flexible portion can be completely removed from the end portion of the groove so as not to remain on the flexible portion and the rigid portion.

  Moreover, this invention has the effect which presses and reinforces the coverlay film with a flat reinforcing metal pattern from the top. Also, the end of the rigid build-up layer with the wall surface of the groove as the end face is formed by the groove formed by digging the build-up layer vertically on the reinforcing metal pattern at the boundary between the rigid part and the flexible part Is done. Therefore, in the flexible part adjacent to the rigid part, a part of the resin of the buildup layer does not cover the upper surface of the flexible part. As such, since the resin of the build-up layer covering the upper surface of the flexible part does not remain and does not impair the flexibility of the flexible part, the boundary part between the rigid part and the flexible part is flexible, and the bending is repeated. There is an effect that a flexible part having high durability can be obtained.

(A) It is a top view of the rigid flexible printed wiring board of the 1st Embodiment of this invention. (B) It is a sectional side view of the rigid flexible printed wiring board of the 1st Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 1st Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 1st Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 1st Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 1st Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 1st Embodiment of this invention. (P) It is a top view explaining the manufacturing method of the rigid flexible printed wiring board of the 1st Embodiment of this invention. (Q) It is sectional drawing of FIG.7 (p). (R) It is sectional drawing of the front of the rigid flexible printed wiring board of FIG.7 (p). (S) It is front sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 1st Embodiment of this invention. (T) It is a top view explaining the manufacturing method of the rigid flexible printed wiring board of the 1st Embodiment of this invention. (U) It is sectional drawing of FIG.9 (t). It is sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 2nd Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 2nd Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the rigid flexible printed wiring board of the 2nd Embodiment of this invention.

<First Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A shows a plan view of a 10-layer rigid flexible printed wiring board 10 having both a rigid portion 101 and a flexible portion 102 according to the first embodiment of the present invention, and FIG. FIG. 2 to 9 are a side cross-sectional view and a plan view for explaining a method of manufacturing the rigid flexible printed wiring board 10 of the first embodiment.

  As shown in FIG.1 (b), the rigid flexible printed wiring board 10 of 1st Embodiment is flexible with the thickness which consists of organic resins, such as an epoxy resin, a polyimide resin, and a polyester resin, 10 micrometers or more and 100 micrometers or less. It has a film-like support film 1 with a center. A wiring pattern 2 is formed on the front and back surfaces of the support film 1 by etching the copper foil 2a.

  As shown in FIG. 2C, both surfaces of the support film 1 made of a flexible insulating resin on which the wiring pattern 2 is formed are covered with a coverlay film 20 with a copper foil. The cover lay film 20 with a copper foil has a copper foil 20a having a thickness of about 12 μm attached to one surface, and an insulating resin film 21 such as a polyimide film having a thickness of 8 μm to 13 μm, which is a lower layer of the copper foil 20a. An adhesive layer 22 is formed on the insulating resin film 21 to a thickness of about 20 μm. The coverlay film 20 with a copper foil is a film having an overall thickness of 40 μm to 50 μm. The coverlay film 20 with copper foil is adhered to both surfaces of the support film 1 to form the inner layer flexible wiring board 30.

As shown in FIG. 3 (e), the inner layer flexible wiring board 30 has a metal pillar intermediate land 3 on the lower surface of the flexible wiring board 1 a, and a coverlay film 20 with copper foil from the upper surface of the inner layer flexible wiring board 30. The second via hole 3a is formed through the layer of the support film 1 and the metal pillar intermediate land 3, and the coverlay film 20 with copper foil is formed from the lower surface of the inner flexible wiring board 30. A metal pillar via hole 23a that penetrates the layer and reaches the metal pillar intermediate land 3 is formed. Further, the metal pillar intermediate land 4 on the upper surface of the flexible wiring board 1a penetrates the layer of the coverlay film 20 with copper foil and the layer of the support film 1 from the lower surface of the inner flexible wiring board 30 to the middle of the metal pillar. A metal pillar via that forms a second via hole 4a leading to the land 4 and penetrates the layer of the cover foil film 20 with copper foil from the upper surface of the inner flexible wiring board 30 to the metal pillar intermediate land 4 Hole hole 23a is formed.

  Then, as shown in FIG. 3 (f), the second floor high via holes 3a, 4a and the metal pillar via hole 23a are filled with an electrolytic copper plating layer, and the second floor high via holes 3b, 4b By forming the blind via hole 23, the first metal plating column connecting the second floor high via hole 3b, the metal pillar intermediate land 3, and the blind via hole 23 is formed from the upper surface to the lower surface of the inner layer flexible wiring board 30. Then, the second metal plating column connecting the second-floor high via hole 4b, the metal column intermediate land 4, and the blind via hole 23 is formed from the lower surface to the upper surface of the inner layer flexible wiring board 30.

  And the rigid part 101 is laminated | stacked on the surface of the front side of the area | region containing the 1st metal plating pillar or the 2nd metal plating pillar of a part of this inner-layer flexible wiring board 30, and a back side surface, Other than the rigid part 101 The rigid flexible printed wiring board 10 in which the flexible layer 102 is the portion of the inner layer flexible wiring board 30 is manufactured.

  In this rigid flexible printed wiring board 10, in particular, the first metal plating column and the second metal plating column formed on the inner layer flexible wiring board 30 are filled with metal plating in a columnar shape in the upper and lower buildup layers 40d. Thus, a strong multilayer metal plating column connected to the blind via hole 41 is formed.

  The multi-layer metal plating pillars are bitten into the rigid portion 101 and are firmly held, and the metal pillar lands 3c and the metal pillar intermediate lands 3 formed above and below the second-floor high via hole 3b are connected to the inner flexible wiring board 30. The upper layer of the coverlay film 20 and the layer of the support film 1 are sandwiched and held from above and below. In addition, the metal pillar intermediate lands 4 and the metal pillar lands 4c formed above and below the second-floor high via hole 4b connect the upper support film 1 layer and the coverlay film 20 layer of the inner flexible wiring board 30 to each other. Hold it from above and below. Thereby, the cover lay film 20 is firmly bonded to the resin layer of the support film 1, and there is an effect of improving the reliability of joining between the cover lay film 20 and the support film 1.

(Production method)
Below, with reference to FIGS. 2-9, the manufacturing method of the 10-layer rigid flexible printed wiring board 10 of embodiment of this invention is demonstrated.

(Inner layer flexible wiring board manufacturing method)
First, the manufacturing method of the inner layer flexible wiring board 30 which comprises the rigid flexible printed wiring board 10 is demonstrated.

(Process 1)
As shown in FIG. 2A, a normal flexible wiring board 1a is prepared as a material for forming the flexible portion 102. The flexible wiring board 1a is a flexible wiring board 1a having a copper foil 2a on both sides and the base material of the support film 1 holding the copper foil 2a made of a flexible heat-resistant resin such as polyimide. . The flexible wiring board 1a used here preferably has no adhesive layer between the copper foil 2a constituting the flexible wiring board 1a and the support film 1 in order to improve bendability and bendability. It is also possible to use the flexible wiring board 1a having a layer.

(Process 2)
Next, as shown in FIG. 2B, by etching the copper foil 2a of the flexible wiring board 1a, the wiring pattern 2 is formed on both surfaces of the flexible wiring board 1a, and the metal pillar intermediate land 3 is formed on the lower surface. The metal pillar intermediate land 4 is formed on the upper surface, and the land 2b is formed at the position of the blind via hole 24 to be formed later.

(Process 3)
As shown in FIG. 2 (c), a coverlay film 20 with a copper foil comprising a copper foil 20a, an insulating resin film 21 such as a polyimide film, and a thermosetting adhesive layer 22 is laminated on both surfaces of the flexible wiring board 1a. Then, the inner layer flexible wiring board 30 as shown in FIG.

(Process 4)
Next, as shown in FIG. 3 (e), the copper foil 20a of the coverlay film 20 with the copper foil of the inner layer flexible wiring board 30 is connected to the front and back portions of the inner metal pillar intermediate lands 3 and 4 and the land. The portion on the outer layer side of 2b is removed by etching, and the underlying insulating resin film 21 is exposed.

(Process 5)
And the metal of the lower surface of the flexible wiring board 1a is irradiated from the surface of the insulating resin film 21 exposed on the front and back of the substrate using a laser drilling device such as a carbon dioxide laser or a YAG laser. A hole for a second floor high via hole that extends from the upper surface of the inner layer flexible wiring board 30 to the intermediate intermediate land 3 through the layer of the coverlay film 20 with copper foil and the layer of the support film 1 in the intermediate intermediate land 3. 3a is formed, and a metal pillar via hole 23a extending from the lower surface of the inner flexible wiring board 30 to the metal pillar intermediate land 3 through the layer of the cover foil film 20 with copper foil is formed.

 Further, the metal pillar intermediate land 4 on the upper surface of the flexible wiring board 1a penetrates the layer of the coverlay film 20 with copper foil and the layer of the support film 1 from the lower surface of the inner flexible wiring board 30 to the middle of the metal pillar. A metal pillar via that forms a second via hole 4a leading to the land 4 and penetrates the layer of the cover foil film 20 with copper foil from the upper surface of the inner flexible wiring board 30 to the metal pillar intermediate land 4 Hole hole 23a is formed. Further, a blind via hole hole 24a reaching the land 2b is formed from the outer layer side portion of the land 2b.

  The shape of the metal pillar via hole 23a and the blind via hole 24a is a hole having a diameter of 50 to 150 μm on the surface of the substrate on the side where the drilling laser light is incident. The diameter of the metal pillar via hole 23a at the position of the metal pillar intermediate lands 3 and 4 is formed as a frustum-shaped metal pillar via hole 23a having a diameter of 50 μm, which is about 30 μm smaller than the diameter on the surface of the substrate. To do.

(Step 6)
Next, after the substrate is immersed in a desmear solution, the second-floor high via hole holes 3a and 4a, the metal pillar via hole 23a, and the blind via hole 24a are subjected to a desmear process. By immersing the substrate in an electroless copper plating solution, the second floor high via hole holes 3a and 4a, the metal pillar via hole 23a, and the blind via hole hole 24a are electroless copper plated. Form a film.

(Step 7)
Next, as shown in FIG. 3 (f), the cathode of the electrolytic copper plating apparatus is connected to the copper foil 20a underlying the substrate, and the substrate is immersed in an electrolytic copper plating bath to which a smoothing agent is added. Is sufficiently stirred to increase the flow rate of the copper plating bath on both surfaces of the inner flexible wiring board 30 to perform a panel plating process for electrolytic copper plating on the entire surface of the substrate.

  Thereby, the smoothing agent suppresses the growth of the copper plating layer on both surfaces of the inner layer flexible wiring board 30, while the second floor high via hole 3a and 4a, the metal pillar via hole 23a, and the blind via hole. The growth of the electrolytic copper plating layer filling the hole 24a for use is not suppressed. Therefore, second floor high via holes 3a and 4a, metal pillar via hole 23a, and blind via hole 24a filled with electrolytic copper plating, second floor high via holes 3b and 4b, and blind via While the ahos 23 and 24 are formed, the thickness of the copper plating layer formed on both surfaces of the inner layer flexible wiring board 30 can be made thinner than the radius of the second floor high via holes 3b and 4b. By the above processing, a copper plating layer having a thickness of about 16 μm, which is 40% of the radius of the second-floor high via hole 3a and 4a, is formed on both surfaces of the inner-layer flexible wiring board 30.

  Thus, as shown in FIG. 3 (f), the second floor high via holes 3a, 4a and the metal pillar via hole holes 23a are filled with an electrolytic copper plating layer, and the second floor high via holes 3b, 4b. By forming the blind via hole 23, the first metal plating column connecting the second floor high via hole 3b, the metal column intermediate land 3, and the blind via hole 23 from the upper surface to the lower surface of the inner layer flexible wiring board 30 is formed. The second metal plating column is formed by connecting the second floor high via hole 4b, the metal column intermediate land 4, and the blind via hole 23 from the lower surface to the upper surface of the inner layer flexible wiring board 30. Further, the blind via hole 24 is formed by filling the hole 24a for the blind via hole with copper plating.

(Process 8)
Next, the copper plating layer on the surface of the substrate is protected and etched with the etching resist pattern, and the etching resist is peeled off after the etching.

  By etching the copper plating layer, as shown in FIG. 3G, the metal column land 3c, the second-floor high via hole 3b, and the metal column intermediate land are formed on the rigid portion 101 from the upper surface to the lower surface of the inner layer flexible wiring board 30. 3. Form a first metal plating column connecting the blind via hole 23 and the land 23b, and from the lower surface to the upper surface of the inner layer flexible wiring board 30, the metal column land 4c, the second floor high via hole 4b, and the metal column intermediate land 4. A second metal plating column connecting the blind via hole 23 and the land 23b is formed. Further, on the surface of the insulating resin film 21 of the rigid portion 101, lands 24b connected to the blind via holes 24, a pattern of alignment marks 26, a reinforcing metal pattern 25, and other wiring patterns are formed.

  In particular, the reinforcing metal pattern 25 is formed at the boundary portion between the rigid portion 101 and the flexible portion 102. The reinforcing metal pattern 25 is used as a stopper layer that blocks the processing laser light L to be irradiated later on the boundary portion between the flexible portion 102 and the rigid portion 101 at that position.

  In step 8, the blind via holes 23 and 24 formed by embedding in the thin coverlay film 20 layer laminated on the multilayered flexible wiring board 1a are connected to the wiring pattern of the flexible wiring board 1a. As the blind via hole is formed and the height of the blind via hole is reduced, the blind via holes 23 and 24 can be formed finely by reducing the diameters of the lands 23b and 24b. Therefore, the wiring pattern can be formed with high density on the insulating resin film 21 of the cover lay.

  Further, the metal pillar lands 3c and the metal pillar intermediate lands 3 formed above and below the second-floor high via hole 3b connect the layer of the coverlay film 20 on the upper layer of the inner flexible wiring board 30 and the layer of the support film 1 to each other. Hold it from above and below. In addition, the metal pillar intermediate lands 4 and the metal pillar lands 4c formed above and below the second-floor high via hole 4b connect the upper support film 1 layer and the coverlay film 20 layer of the inner flexible wiring board 30 to each other. Hold it from above and below. Thereby, the cover lay film 20 is firmly bonded to the resin layer of the support film 1, and there is an effect of improving the reliability of joining between the cover lay film 20 and the support film 1.

  Further, a land 2b connected to the blind via hole 24 on the inner layer side, a metal pillar intermediate land 3 or 4 connected to the blind via hole 23 on the inner layer side, and lands 23b and 24b connected to the blind via holes 23 and 24 on the outer layer side. However, there is an effect that the insulating resin film 21 and the adhesive layer 22 are sandwiched and held from above and below, and the insulating resin film 21 and the adhesive layer 22 can be directly and firmly held.

  In particular, since the metal pillar lands 3c, 4c and lands 23b, 24b are formed from the copper foil 20a of the layer in contact with the insulating resin film 21 of the coverlay, the layers of the lands 23b, 24b and the inner metal pillar intermediate land 3 or 4 or the space between the land 2b and the upper and lower layers can be reduced. Accordingly, there is an effect that the insulating resin film 21 and the adhesive layer 22 sandwiched between the lands of those layers can be sandwiched between the upper and lower lands and strongly held.

  In addition, it is desirable to mix the first metal plating column and the second metal plating column in the left and right rigid portions 101 in FIG. As described above, when the first metal plating column and the second metal plating column are mixed in one rigid part, the mechanical stress applied to the rigid part is the metal column intermediate land 3 or 4 connecting the upper and lower blind via holes 23. The stress is distributed to the lower surface and the upper surface of the flexible wiring board 1a in the metal pillar intermediate land 3 on the lower surface of the flexible wiring board 1a and the metal pillar intermediate land 4 on the upper surface of the flexible wiring board 1a. Thereby, the mechanical stress applied to the rigid portion is distributed to the lower surface and the upper surface of the flexible wiring board 1a, so that the rigid portion can be strengthened against the mechanical stress, and the reliability of the rigid flexible printed wiring board 10 can be increased. effective.

(Step 9)
Next, as shown in FIG. 4H, a thin release film 31 is placed on the insulating resin film 21 of the coverlay of the inner layer flexible wiring board 30 and the reinforcing metal pattern 25 thereon. The thin release film 31 covers the region of the flexible portion 102 of the rigid flexible printed wiring board 10 and is installed in the region over the reinforcing metal pattern 25. The positions of the end portions of the thin release film 31 are accurately aligned with the positions of the first groove 27a and the second groove 27b to be formed later on the reinforcing metal pattern 25 with reference to the alignment mark 26. Install.

  The flexible portion 102 covered with the thin release film 31 is exposed when the rigid flexible printed wiring board 10 is completed. As the thin release film 31, a fluorine-based resin film, a PBT film, a PP stretched film, a PET film, a polyolefin film, or the like that can be easily peeled off from the coverlay film 20 on the surface of the flexible portion 101 is used.

(Process 10)
Next, as shown in FIG. 4 (i), the melt viscosity excellent in embedding between circuit patterns and surface smoothness after lamination on both surfaces of the inner layer flexible wiring board 30 is 1000 poise (10000 Pa · s) or less. The prepreg 40a and the thin copper foil 40b are combined and heated and pressed to form the buildup layer 40d as shown in FIG. 4 (j).

(Step 11)
Next, as shown in FIG. 5 (k), by using a carbon dioxide laser processing device, blind drilling is performed from above the thin copper foil 40b by laser drilling in which the laser beam irradiation position is aligned based on the alignment mark 26. Holes 41a and 42a for via holes 41 and 42 are formed. The holes 41 a and 42 a have a diameter of about 70 to 150 μm and form holes reaching the second floor high via holes 3 b and 4 b and the blind via holes 23 and 24.

(Step 12)
Next, as shown in FIG. 5 (l), by performing a panel plating process for copper plating on the entire surface of the substrate, the holes 41a and 42a for the blind via holes 41 and 42 of the substrate are filled with the copper plating and the blind via holes are formed. 41 and 42 are formed.

(Step 13)
Next, as shown in FIG. 5M, by etching the copper plating layer on the surface of the substrate, the blind via holes 41 and 42 connected to the second floor high via holes 3b and 4b and the blind via holes 23 and 24 are formed. A wiring pattern including the pattern and the copper foil pattern 43 for processing laser stopper is formed.

  Thereby, the blind via hole 24 is connected to the blind via hole 42 of the front-side buildup layer 40d, and the columnar copper plating composed of the blind via holes 42 and 24 is embedded and supported in the buildup layer 40d. There is an effect to be supported more firmly.

  The processing laser stopper copper foil pattern 43 formed below the inner layer flexible wiring board 30 is later processed laser light L irradiated from the upper surface side of the rigid flexible printed wiring board 10 as shown in FIG. The pattern of the copper foil pattern 43 for a laser stopper for processing is formed at a position where it is cut off at a position on the lower surface side of the inner layer flexible wiring board 30.

  The copper foil pattern 43 for processing laser stopper formed here is used as follows. That is, in a later step, a groove that separates the surface build-up layer of the flexible portion 102 and the rigid portion 101 by irradiating the processing laser beam on the reinforcing metal pattern 25 between the flexible portion 102 and the rigid portion 101. Form. At that time, the laser beam for processing is stopped at the copper foil pattern 43 for processing laser stopper, and the resin for the build-up layer between the lower layer and the reinforcing metal pattern 25 has a processing laser stopper. There is an effect that the processing laser light can be accurately aligned and irradiated on the area other than the copper foil pattern 43 for processing.

(Step 14)
Next, by repeating the same process as the process from the process 10 to the process 13, the build-up layers 50d and 60d are sequentially formed from the inner layer side to the outer layer side of both surfaces of the substrate as shown in FIG. 6 (n). To do. A blind via hole 51 connected to the blind via hole 41 is formed in the buildup layer 50d, and a blind via hole 61 connected to the blind via hole 51 is formed in the buildup layer 60d.
(Step 15)
Next, the solder resist 70 is printed on the rigid portion 101 as shown in FIG.

(Step 16)
Next, as shown in the plan view of FIG. 7 (p), the side view of FIG. 7 (q), and the side view of FIG. 8 (r), a carbon dioxide laser or the like aligned with the alignment mark 26 as a reference. The processing laser beam L is irradiated from the surface buildup layer on the reinforcing metal pattern 25 at the boundary between the flexible portion 102 and the rigid portion 101 until the reinforcing metal pattern 25 is reached. That is, by the processing laser beam L, the first groove 27a that separates the build-up layer on the surface of the flexible portion 102 from the left rigid portion 101 in FIG. 7 (q), and the right rigid portion 101 in FIG. 7 (q). A second groove 27b is formed to separate the.

  In this processing, an alignment mark 26 is formed on the outer layer side surface of the cover lay film 20, and the thin release film 31 placed over the reinforcing metal pattern 25 with reference to the alignment mark 26. The first groove 27a and the second groove 27b are formed by irradiating the end portion with the processing laser beam L with its position accurately aligned. Thereby, the thin release film 31 remains only between the first groove 27a and the second groove 27b, and the thin release film 31 can remain only in the build-up layer on the flexible region. Therefore, when removing the build-up layer on the area of the flexible part 102, the thin release film 31 is also completely removed so that it does not remain on the rigid flexible printed wiring board 10.

  Further, the processing laser beam L is irradiated from the upper surface side and the lower surface side of the substrate, and the individual rigid flexible printed wiring boards 10 are cut out from the substrate. For example, as shown in FIG. 8 (r), the processing laser beam L irradiated from the upper surface side of the substrate is grooved until reaching the processing laser stopper copper foil pattern 43 at the position on the lower surface side of the inner layer flexible wiring board 30. And the flexible portion 102 of the rigid flexible printed wiring board 10 is cut out from the substrate.

(Modification 1)
As a first modification, the outer shape processing for cutting out each rigid flexible printed wiring board 10 from the substrate can be performed by mechanical outer shape router processing.

(Step 17)
After cutting out the flexible portion 102 of the rigid flexible printed wiring board 10 from the substrate in which grooves are formed in the substrate with the processing laser light L, as shown in FIGS. 8 (s) and 9 (u), from the upper surface of the substrate, The thin release film 31 and the buildup layers 40d, 50d, and 60d between the first groove 27a and the second groove 27b thereon are peeled off. Further, the resin layer on the lower surface is peeled off from the rigid flexible printed wiring board 10. That is, the build-up layer 40d that is connected to the outer frame portion of the substrate between the first release groove 27a and the second release groove 27b below the thin release film 31 on the lower surface of the rigid flexible printed wiring board 10. , 50d, 60d. Thereby, the flexible part 102 of the rigid flexible printed wiring board 10 can be peeled off from the buildup layers 40d, 50d, and 60d, and the individual rigid flexible printed wiring board 10 can be separated from the outer frame portion of the substrate.

  Here, the thin release film 31 is peeled off and removed from the flexible portion 102 of the rigid flexible printed wiring board 10, and the thin release film 31 does not remain, so that the electrical characteristics of the surface of the flexible portion are the material of the thin release film 31. There is an effect that is not affected.

  Further, the cross sections of the build-up layers 40 d, 50 d, and 60 d exposed in the grooves formed by the processing laser beam L form the end portion of the rigid portion 101. The rigid flexible printed wiring board 10 manufactured in the present embodiment performs an inspection for comparing the position of the end portion of the rigid portion 101 with the position of the alignment mark 26, thereby shifting the position of the end portion of the rigid portion 101. The amount can be inspected with the finished product.

In the first embodiment, the second-floor high via holes 3b and 4b and the blind via holes 23 and 24 formed in the inner layer flexible wiring board 30 are connected to the blind via holes 41 and 42, and the blind via holes 41 and 42 are connected to each other. It bites into the rigid part 101 and is firmly held. At the same time, the lands 23b and 3 or 4 connected to the blind via hole 23 with a narrow space and the lands 24b and 2b connected to the via hole 24 with a small space are bonded to the insulating resin film 21 of the coverlay film 20. The agent layer 22 is held from above and below. Since the structure firmly bonds the coverlay film 20 to the support film 1 and the buildup layer 40d of the rigid portion 101, there is an effect that the reliability of bonding between the coverlay film 20 and the upper and lower resin layers can be increased.

  In particular, the flat coverlay film 20 on the outer layer side of the inner layer flexible wiring board 30 is held by pressing the coverlay film 20 from above and below with the reinforcing metal pattern 25 formed directly on the outer layer. There is an effect that the plate 30 is reinforced so that a large stress is not concentrated on the boundary portion between the rigid portion 101 and the flexible portion 102 with a small curvature radius.

  The boundary portion between the rigid portion 101 and the flexible portion 102 is separated by grooves 27 a and 27 b formed by the processing laser light L reaching the upper surface of the reinforcing metal pattern 25, and covers the surface of the flexible portion 102. Since the thin release film 31 is removed from the flexible portion 102 together with the buildup layer, the resin is not covered on the upper surface of the reinforcing metal pattern 25. Thus, on the rigid portion 101 side, the end of the build-up layer is formed vertically on the reinforcing metal pattern 25 as the side surfaces of the grooves 27a and 27b formed by the processing laser beam L, and the reinforcing metal pattern Since the upper surface of 25 is not covered with resin, the boundary portion between the rigid portion 101 and the flexible portion 102 is flexible, and there is an effect that the durability to repeated bending is high.

  In the prior art, a build-up layer of the rigid portion 101 is formed by laminating a low-flow resin sheet on the inner layer flexible wiring board 30, and each time the build-up layer is formed, the pattern and via hole of the rigid portion 101 are formed. In many cases, a technique of performing a copper plating process for forming the film is used. In that case, the copper plating remained on the surface of the flexible portion 102, and the problem of hindering the bendability of the flexible portion 102 occurred. On the other hand, in this embodiment, since the buildup layers 40d, 50d, and 60d on the flexible portion 102 are removed after the buildup layers 40d, 50d, and 60d are formed on the inner layer flexible wiring board 30, the rigid portion Excess copper plating is not formed on the surface of the flexible portion 102 by the copper plating process in forming the pattern 101 and the via hole. Therefore, in this embodiment, there is no problem of hindering the bendability of the flexible portion 102 that occurs when copper plating remains on the surface of the flexible portion 102, and the rigid flexible printed wiring board 10 having excellent bendability is provided. There is an effect to be obtained.

<Second Embodiment>
10-12 is a sectional side view explaining the manufacturing method of the rigid flexible printed wiring board 10 of the 2nd Embodiment of this invention. FIG. 12H is a side sectional view of the rigid flexible printed wiring board 10 according to the second embodiment. The rigid flexible printed wiring board 10 of the second embodiment has a second floor high via hole 3f that extends from the upper surface of the inner layer flexible wiring board 30 to the metal pillar intermediate land 3 on the lower surface of the flexible wiring board 1a. From the lower surface of the inner layer flexible wiring board 30, there are blind via holes 23 that penetrate the insulating resin film 21 and the adhesive layer 22 of the coverlay film 20 with copper foil and reach the metal pillar intermediate lands 3. Thus, the first-layer metal wiring pillar 30 having the second-floor high via hole 3f, the metal pillar intermediate land 3, and the blind via hole 23 is provided from the upper surface to the lower surface of the inner layer flexible wiring board 30.

Similarly, it has a second-floor high via hole 4f that extends from the lower surface of the inner layer flexible wiring board 30 to the metal pillar intermediate land 4 on the upper surface of the flexible wiring board 1a, while from the upper surface of the inner layer flexible wiring board 30. Has a blind via hole 23 that penetrates through the insulating resin film 21 and the adhesive layer 22 of the coverlay film 20 with copper foil and reaches the metal pillar intermediate land 4. Thereby, from the lower surface to the upper surface of the inner-layer flexible wiring board 30, the second-floor high via hole 4f
, The metal column intermediate land 4 and the second metal plating column connected to the blind via hole 23.

  The second embodiment is different from the first embodiment in that the second-floor high via hole 3f and the second-floor high via hole 4f have metal pillar lands 3g and 4g in their outermost layers, and the second-floor high In the middle part of the via hole, there are first floor lands 3d and 4d formed with holes 3e and 4e in the center. The diameters of the second floor high via holes 3f and 4f on the inner layer side of the first floor lands 3d and 4d are as follows. The diameter of the holes 3e and 4e of the first-floor lands 3d and 4d. The diameter of the second floor high via hole formed on the outer layer side of the first floor lands 3d and 4d is larger than the diameter on the inner layer side.

  In the second embodiment, the first floor lands 3d and 4d having holes 3e and 4e formed at the center are provided in the middle part of the second floor high via hole, so that the outermost layer portion of the second floor high via hole 3f is provided. The connected metal pillar lands 3g and 4g and the first-floor lands 3d and 4d connected to the middle part of the second-floor high via hole sandwich and hold the insulating resin film 21 and the adhesive layer 22 therebetween. In addition, there is an effect that the insulating resin film 21 and the adhesive layer 22 can be directly and firmly held. Thereby, the reliability of bonding between the adhesive layer 22 of the cover lay film 20 and the resin layer of the support film 1 and the reliability of bonding between the insulating resin film 21 of the cover lay film 20 and the buildup layer 40d are improved. There is an effect to make.

(Production method)
In the method of manufacturing the rigid flexible printed wiring board 10 of the second embodiment, the process 1 uses the same flexible wiring board 1a as the process 1 of the first embodiment as shown in FIG.
(Process 2)
In step 2, as shown in FIG. 10B, the copper foil 2a of the flexible wiring board 1a is etched to form the wiring pattern 2 on both surfaces of the flexible wiring board 1a as in the first embodiment. The metal column intermediate land 3 is formed on the upper surface, the metal column intermediate land 4 is formed on the upper surface, and the land 2b is formed at the position of the blind via hole 24 to be formed later. In the second embodiment, the first floor land 3d having a hole 3e formed at the center is formed on the upper surface of the flexible wiring board 1a at a position corresponding to the metal pillar intermediate land 3 on the lower surface. On the lower surface of 1a, a first-floor land 4d having a hole 4e in the center is formed at a position corresponding to the metal pillar intermediate land 4 on the upper surface.

In step 3 and step 4 of the second embodiment, as in the first embodiment, a substrate is formed as shown in FIGS.
(Process 5)
In step 5, as in step 5 of the first embodiment, as shown in FIG. 11E, a laser drilling device such as a carbon dioxide gas laser or a YAG laser is formed from the surface of the insulating resin film 21 exposed on the front and back of the substrate. Irradiate a laser beam for drilling. As a result, the metal pillar intermediate land 3 on the lower surface of the flexible wiring board 1a passes through the layer of the coverlay film 20 with copper foil and the layer of the support film 1 from the upper surface of the inner flexible wiring board 30 to the middle of the metal pillar. A hole 2a for a second floor high via hole reaching the land 3 is formed. In the second embodiment, the drilling laser light is blocked by the first-floor land 3d, and only the light that has passed through the holes 3e of the first-floor land 3d reaches the metal pillar intermediate land 3. As a result, the hole 2a for the second floor high via hole has the diameter of the hole 3e at the center of the first floor land 3d in the lower layer portion of the first floor land 3d, the diameter is smaller than the upper layer portion, and the diameter is stepped. A second-floor high via hole 3a having a step is formed.

Similarly, from the lower surface of the inner layer flexible wiring board 30, a second-floor high via-hole hole 4 a that penetrates the layer of the coverlay film 20 with copper foil and the layer of the support film 1 and reaches the metal pillar intermediate land 4 is formed. Form. Similarly to the second floor high via hole 3a, the second floor high via hole 4a is blocked by the first floor land 4d and the light passing through the hole 4e of the first floor land 4d only in the surrounding laser beam for drilling. However, it reaches the metal pillar intermediate land 4. Thereby, the hole 4a for the second floor high via hole has the diameter of the hole 4e at the center of the first floor land 4d in the upper layer portion of the first floor land 4d, and has a diameter smaller than that of the lower layer portion and has a stepped diameter. A second-floor high via hole 4a having a step is formed.

(Step 6 and Step 7)
As shown in FIG. 11 (f), the second floor high via hole 3f can be obtained by filling the second floor high via hole holes 3a and 4a with electrolytic copper plating in the same manner as in steps 6 and 7 of the first embodiment. And 4f and other blind via holes 23 and 24 are formed.

  In particular, the second-floor high via hole 3f is formed in an electrolytic copper-plated metal column having a stepped step whose diameter is larger than that of the lower layer portion in the upper layer portion of the first-floor land 3d, and the upper layer portion has a lower layer diameter. The second-floor high via hole 3f is connected to the first-floor land 3d in a larger area by an amount larger than the diameter of the portion, and there is an effect that the connection reliability between the second-floor high via hole 3f and the first-floor land 3d is high.

(Process 8)
Next, a wiring pattern is formed by etching. As shown in FIG. 12G, the metal pillar land 3g, the second-floor high via hole 3f, the metal are formed on the rigid portion 101 from the upper surface to the lower surface of the inner layer flexible wiring board 30. A first metal plating column connecting the column intermediate land 3, the blind via hole 23, and the land 23b is formed, and the metal column land 4g, the second-floor high via hole 4f, the metal are formed from the lower surface to the upper surface of the inner layer flexible wiring board 30. A second metal plating column connecting the column intermediate land 4, the blind via hole 23, and the land 23b is formed.

(From step 9 to step 17)
The rigid flexible printed wiring board 10 shown in FIG. 12H is manufactured by the same processes as the processes 8 to 17 of the first embodiment.

  In addition, this invention is not limited to said embodiment, The position of the alignment mark 26 formed on the insulating resin film 21 of a coverlay is not limited to the rigid part 101, The alignment mark 26 is set to the flexible part 102. Can also be formed. When the alignment mark 26 is formed on the flexible portion 102, the alignment mark 26 is exposed to the flexible portion 102, and the position can be easily observed. Therefore, the rigid flexible print formed by aligning the position with the alignment mark 26 is provided. There is an effect that the measurement of the positional deviation from each part of the wiring board 10 becomes easy. For example, it is easy to measure the amount of deviation between the position of the side surface of the end of the build-up layers 40d, 50d, and 60d formed vertically by the grooves 27a and 27b on the reinforcing metal pattern 25 and the alignment mark 26. There is an effect to become.

DESCRIPTION OF SYMBOLS 1 ... Support film 1a ... Flexible wiring board 2 ... Wiring pattern 2a ... Copper foil 2b, 23b, 24b ... Land 3, 4 ... Metal pillar intermediate land 3a, 4a ... 2nd floor high via holes 3b, 4b, 3f, 4f ... 2nd floor high via holes 3c, 4c, 3g, 4g ... Metal pillar lands 3d, 4d ... 1st floor lands 3e, 4e ... -Hole 10 ... Rigid flexible printed wiring board 20 ... Coverlay film 20a with copper foil ... Copper foil 21 ... Insulating resin film 22 ... Adhesive layer 23, 24, 41, 42, 51, 61 ... Blind via hole 23a ... Metal pillar via hole 24a ... Blind via hole 25 ... Reinforcing metal pattern 26 ... Alignment mark 27a ... No. 1 groove 2 b ... 2nd groove | channel 30 ... Inner layer flexible wiring board 31 ... Thin peeling film 40a ... Prepreg 40b ... Thin copper foil 40d, 50d, 60d ... Build-up layer 43 ... Copper foil pattern 101 for processing laser stopper ... Rigid portion 102 ... Flexible portion L ... Laser beam for processing

Claims (4)

  A rigid flexible printed wiring board in which a rigid rigid part is connected via a flexible flexible part, and a metal column intermediate land is formed on a surface of a support film that extends over the region of the rigid part and the flexible part. It has an inner layer flexible wiring board formed by laminating coverlay films on both sides of the film, has a hole reaching the metal pillar intermediate land from both sides of the inner layer flexible wiring board, and filled with metal plating in the hole A metal plating column formed integrally with the metal column intermediate land, and a metal pattern for reinforcement at a boundary portion between the alignment mark and the flexible portion and the rigid portion is formed on the surface of the inner layer flexible wiring board, A build-up layer is laminated in the region of the rigid portion of the inner layer flexible wiring board, and the position is aligned with the alignment mark, Rigid flexible printed wiring board, wherein a side surface of the end portion of the buildup layer is vertically formed on the metal reinforcement pattern.   2. The rigid flexible printed wiring board according to claim 1, wherein a portion of the metal plating column on one side of the metal column intermediate land has a metal column land in an outermost layer portion and a first floor land in an intermediate portion. A rigid flexible printed wiring board, being a second-floor high via hole, wherein a diameter of the second-floor high via hole on the outer layer side of the first-floor land is larger than a diameter on the inner layer side.   A rigid flexible printed wiring board manufacturing method in which a rigid rigid part is connected via a flexible flexible part, wherein the rigid film part and the support film spanning the flexible part area are provided on the at least one side of the support film. From the step of forming the metal pillar intermediate land in the region of the rigid part, the step of manufacturing the inner layer flexible wiring board by laminating the coverlay film with copper foil on both sides of the support film, and the both sides of the inner layer flexible wiring board A step of forming a hole reaching the metal column intermediate land by irradiating a laser beam for drilling, and a metal plating column formed integrally with the metal column intermediate land by filling the hole with metal plating A step of reinforcing the alignment mark on the surface of the inner layer flexible wiring board and the boundary between the flexible portion and the rigid portion; A step of forming a metal pattern, a step of laminating a buildup layer in the region of the rigid portion of the inner layer flexible wiring board, and a boundary portion between the flexible portion and the rigid portion in alignment with the alignment mark Irradiating the build-up layer with a processing laser beam to form a groove that vertically exposes the side surface of the end of the build-up layer on the reinforcing metal pattern; The manufacturing method of the rigid flexible printed wiring board characterized by having the process of isolate | separating and removing the said buildup layer and the said thin peeling film on a part. It is a manufacturing method of the rigid flexible printed wiring board according to claim 3,
In the step of forming the metal column intermediate land, in the step of forming a first floor land facing the metal column intermediate land and having a hole in the center, and forming a hole reaching the metal column intermediate land, the metal column intermediate land By irradiating the laser beam for drilling from the surface far from the intermediate land toward the metal pillar intermediate land via the first floor land, the peripheral portion of the drilling laser light is the first floor land. Rigid flexible print characterized in that a step is formed in the diameter of the hole reaching the metal column intermediate land by blocking only the laser beam for drilling that has passed through the hole to reach the metal column intermediate land. A method for manufacturing a wiring board.

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