JP2006147752A - Printed wiring board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board which is superior in rigidity and three-dimensional circuit arrangement property and is applicable to high-temperature reflow mounting, and to provide its manufacturing method. <P>SOLUTION: The printed wiring board is provided with a resin covered part 3 at least in the uneven structural part of a rigid supporting body 1 having the uneven structur part, as well as a circuit that is formed by conductor plating in the resin covered part. The method for manufacturing the printed wiring board includes a step to form an uneven structure in the rigid supporting body, a step to form a resin covered part at least in the uneven structure of the supporting body, a step to apply conductor plating to the entire surface including the resin covered part, and a step to form a circuit on the conductor plating. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printed wiring board, and more particularly to a printed wiring board excellent in rigidity characteristics and three-dimensional circuit arrangement and a manufacturing method thereof.

  Conventionally, as a method of manufacturing a printed wiring board having a three-dimensional structure and a circuit, for example, there is a method of forming a three-dimensional structure by injection molding into a mold and then forming a circuit on the surface of the structure. It has already been reported (see Patent Document 1).

  That is, in the method of manufacturing this printed wiring board, as shown in FIG. 3, a three-dimensional structure a is formed by injection molding an insulating synthetic resin into a mold by a mold resin processing method (see FIG. 3). 3 (a)), and then the conductor plating 5 is applied to the surface of the structure a (FIG. 3 (b)). Thereafter, the circuit 8 is formed to form a printed wiring board having a three-dimensional structure and circuit. (FIG. 3C).

  However, since the printed wiring board thus obtained has a resin-based composition whose structure a is obtained by a mold resin processing method, the following is required in the context of recent printed wiring board requirements. There was a problem like this.

  First, there is a problem of rigidity required for the printed wiring board. In recent years, demands for printed wiring boards include pursuing thinness and downsizing. From the viewpoint of the physical properties of the printed wiring board, a material that can be used without problems in terms of the quality of the printed wiring board even when it is thin and small is required, and its necessary characteristics include rigidity.

  However, in the printed wiring board having the resin-based composition as described above, the resin itself does not have rigidity as compared with a metal material or an inorganic material, and thus cannot meet the demands of the recent printed wiring board. There was a problem. Further, since the resin itself is generally rich in hygroscopicity compared to a metal material or an inorganic material, and a resin with a large moisture absorption amount is fragile, there is a problem in this respect. That is, a printed wiring board having a resin-based composition cannot meet the recent demand for printed wiring boards, and is actually difficult to use.

Next, there is a problem of reflow mounting at a high temperature against the background of lead-free technology in surface mounting technology, which is required for printed wiring boards. Under these high-temperature reflow conditions, if a resin with a low Tg (glass transition point) temperature or a high CTE (linear expansion coefficient) resin is used, the printed wiring board is warped or deformed. There is a problem that the quality and the yield are lowered. That is, in order to cope with recent printed wiring boards that require a reflow process at a high temperature, the resin that can be used in such a printed wiring board as described above is limited, and the width of use is naturally limited. The actual situation was.
JP-A-11-307909

  In view of the conventional problems and actual situations as described above, the present invention provides a printed wiring board that has excellent rigidity characteristics, can be used for reflow mounting at high temperatures, and has excellent three-dimensional circuit layout, and a method for manufacturing the same. Is an issue.

  The present inventor has made various studies in order to solve the above problems. As a result, a base material made of a metal material or an inorganic material having excellent rigidity is used as a base support, and after providing the concavo-convex structure portion on the support, the resin coating portion is applied using the concavo-convex structure portion. To form a three-dimensional structure by forming a circuit by conductor plating, a printed wiring board having excellent rigidity characteristics and three-dimensional circuit arrangement can be found, and the present invention is completed. It came.

  That is, the present invention is characterized in that at least the concavo-convex structure portion of the rigid support having the concavo-convex structure portion has a resin coating portion, and at least the resin coating portion has a circuit formed by conductor plating. The printed wiring board which solves the said subject.

  The present invention also includes a step of forming a concavo-convex structure portion on a rigid support, a step of forming a resin coating portion on at least the concavo-convex structure portion of the support, and a step of conductor plating treatment on the entire surface including the resin coating portion. And a process for forming a circuit on the conductor plating, and the above-mentioned problem is solved by a method for producing a printed wiring board.

  In the present invention, a thermosetting resin or a thermoplastic resin is preferably used as the resin.

  In the present invention, a conductive substrate or an insulating substrate is preferably used as the support.

  Here, examples of the conductive substrate include those made of a metal sheet or a metal foil.

  Moreover, what consists of ceramics is mentioned as an insulating base material.

  Moreover, it is advantageous to use the uneven structure portion of the support in the present invention as an interlayer connection portion.

  In the present invention, the uneven structure portion of the support is preferably formed by bending, punching, crushing, drawing, etching, or laser processing.

  Moreover, it is advantageous to use the uneven structure portion of the support in the present invention as a component mounting pad or land.

  Since the printed wiring board according to the present invention uses a rigid support as a base support, it has excellent rigidity characteristics, can be used for reflow mounting at a high temperature, and is provided on the uneven structure portion of the support. Since the three-dimensional structure is obtained by the covering portion, the three-dimensional circuit arrangement is excellent. In addition, by using the concavo-convex structure portion of the support, it is possible to easily form through holes and non-through holes for connecting the front and back layers.

  The best mode for carrying out the invention will be described with reference to FIG.

  In the present invention, at least one support 1 is prepared first. Since the support body 1 has a main role of rigidity, the material of the support body 1 may be either a conductive base material or an insulating base material as long as the base material can bear the rigidity. Examples of such a base material include a conductive base material such as a metal sheet or a metal plate, or an insulating base material such as ceramics. Further, the support 1 may be used as a material as a conductor depending on the required structure of the printed wiring board. In such a case, a conductive substrate such as the metal sheet or the metal plate is suitable. is there.

  Next, the support body 1 is processed into a lead frame to obtain, for example, a structure having a concavo-convex structure portion shown in FIG. Here, as a processing method for the support 1, in addition to cutting to a predetermined dimension, bending, punching, crushing, drawing, thickness, and size for forming a target three-dimensional structure are performed. Examples include adjustment or press working for creating a shape such as a step. Incidentally, FIG. 1A shows an example in which the punched portion 2 is formed.

  Also, in light of the recent background of small-lot, multi-product production, the creation of a mold when forming a lead frame may cause a delay in production time and cost in the production of prototypes or small-quantity products. Therefore, in the lead frame processing, etching processing or laser processing by a circuit forming method can be used as an alternative method of the processing.

  Next, the resin coating portion 3 is formed on at least the concavo-convex structure portion of the support 1 obtained by the above-described processing to obtain, for example, the structure shown in FIG. The material of this resin does not matter whether it is a thermosetting resin or a thermoplastic resin. Here, as thermosetting resin, phenol resin, epoxy resin, polyimide, bismaleimide triazine resin, melamine resin, cyanate resin, benzocyclobutene resin, unsaturated polyester, polybenzoxazole, polyphenylene ether, polyphenylene oxide, diallyl phthalate resin The thermoplastic resin is preferably polyimide, polyester, liquid crystal polymer, fluororesin, polyether ether ketone, polynorbornene, polyethylene terephthalate, cycloolefin resin, polyphenylene sulfide, polyether sulfone, acrylic resin, etc. Preferably used. Moreover, as a method of forming the resin coating portion 3, an injection molding method using a mold capable of forming a three-dimensional concavo-convex structure is suitable.

  Here, the region where the resin coating portion 3 is formed may be only the concavo-convex structure portion of the support 1 or the entire surface including the concavo-convex structure portion. By forming the resin coating portion 3 on the concavo-convex structure portion of the support 1, steps and concavo-convex can be formed between the support 1 and the resin coating 3, which is advantageous in circuit arrangement and the like. Incidentally, FIG.1 (b) has shown the example which made resin 3 adhere to the extraction part 2 and its circumference | surroundings. Moreover, when the resin coating part 3 is formed in the whole surface of the support body 1, since the resin coating part 3 can be used as an interlayer insulation part of a multilayered structure, it is advantageous.

  Further, when forming the resin coating portion 3 on the support 1, it is possible to form steps or irregularities on the resin coating portion 3 itself by designing the mold in three dimensions, which is the same as described above. It is advantageous in circuit arrangement. Furthermore, it is possible to form a punch in the resin coating 3 itself to form a resin penetration 4 as shown in FIG.

  Next, conductor plating 5 treatment is performed on the structure shown in FIG. 1B obtained as described above to obtain a structure shown in FIG. 1C, for example. The conductor plating 5 is preferably copper plating, nickel plating, or a combination of copper plating and nickel plating, which is performed by sequentially using chemical copper and electrolytic copper, and is applied to the entire surface of the structure. Here, the through copper through-hole 6 can also be formed by attaching conductive copper plating to the wall surface portion of the resin penetrating portion 4 of the structure shown in FIG.

  Next, circuit formation is performed on the structure shown in FIG. 1C obtained as described above to obtain, for example, the structure shown in FIG. As this circuit forming method, an ED (electrodeposition coating) circuit forming method capable of forming a circuit in a three-dimensional structure is suitably used. After the ED etching resist is attached, the circuit 8 and the through-hole 7 after the circuit formation are formed through steps of exposure, development, etching, and peeling.

  Next, surface treatment of nickel / gold plating 9 is performed on the conductor surface of the structure shown in FIG. 1 (d) obtained above to obtain a printed wiring board shown in FIG. 1 (e), for example.

  Hereinafter, the present invention will be further described with reference to examples.

Example 1
A first embodiment of the present invention will be described with reference to FIG. First, as shown to Fig.1 (a), the lead frame process was carried out with the metal mold | die, using the copper plate (thickness: 100 micrometers) as the support body 1. As shown in FIG. Here, the die 2 shown in FIG. 1A was formed using a model that can punch the support 1 as a mold. Moreover, the three-dimensional level | step difference was formed in the support body 1 using the metal mold | die and press work.

  Subsequently, the resin coating part 3 was formed in the support body 1 obtained above, and the structure shown in FIG.1 (b) was obtained. Here, as the resin, an epoxy-containing heat-curable resin widely used for printed wiring boards was used. Further, an injection molding machine was used for forming the resin coating portion 3. At this time, the mold used for injection molding was designed so that a penetration structure could be formed, and the resin penetration part 4 was provided in the resin coating part 3 itself.

  Next, copper plating (thickness: 20 μm) was applied as the conductor plating 5 to the structure shown in FIG. 1B obtained above to obtain the structure shown in FIG. This conductor plating (copper plating) 5 was performed using chemical copper and electrolytic copper sequentially, and was applied to the entire surface of the structure shown in FIG. Here, conductor plating (copper plating) 5 was attached to the wall surface portion of the resin penetration portion 4 of the structure shown in FIG.

  Next, circuit formation was performed on the structure shown in FIG. 1C obtained above, and the structure shown in FIG. 1D was obtained. Here, as a circuit formation method, an ED (electrodeposition coating) circuit formation method is used, and after the ED etching resist is attached, the circuit 8 and the through hole 7 after the circuit formation are formed through the steps of exposure, development, etching, and peeling. Formed.

  Next, the surface treatment of the nickel / gold plating 9 was performed on the conductor surface of the structure shown in FIG. 1D obtained above to obtain the printed wiring board shown in FIG.

Example 2
A second embodiment of the present invention will be described with reference to FIG. First, as shown in FIG. 2A, a copper plate (thickness: 100 μm) was used as the support 1, and a lead frame was processed by a mold. Here, a bending part 10 shown in FIG. 2A was formed using a model that can bend and bend the support 1 as a mold.

  Subsequently, the resin coating part 3 was formed in the support body 1 obtained above, and the structure shown in FIG.2 (b) was obtained. Here, as the resin, an epoxy-containing heat-curable resin widely used for printed wiring boards was used. Further, an injection molding machine was used for forming the resin coating portion 3. At this time, the resin was adhered so as to follow the support 1, and was further adhered so as to follow the uneven portion of the bent portion 10.

  Next, the structure shown in FIG. 2B was subjected to copper plating (thickness: 20 μm) treatment as the conductor plating 5 to obtain the structure shown in FIG. This conductor plating (copper plating) 5 was performed using chemical copper and electrolytic copper sequentially, and was applied to the entire surface of the structure shown in FIG. Here, conductor plating (copper plating) 5 is also attached to a part of the bent portion 10 of the support 1, and the bent portion 10 is used as an interlayer connection portion 11, thereby obtaining conduction between the front and back of the printed wiring board. It was a possible structure.

  Next, a circuit was formed on the structure shown in FIG. 2C obtained above, and the printed wiring board shown in FIG. 2D was obtained. Here, as a circuit formation method, an ED (electrodeposition coating) circuit formation method was used. After the ED etching resist was attached, the circuit 8 was formed through the steps of exposure, development, etching, and peeling.

The schematic process explanatory drawing which shows the 1st manufacture example of the printed wiring board of this invention. Schematic process explanatory drawing which shows the 2nd manufacture example of the printed wiring board of this invention. Schematic process explanatory drawing which shows the example of manufacture of the conventional printed wiring board.

Explanation of symbols

1: Support body 2: Extraction part 3: Resin coating part 4: Resin penetration part 5: Conductor plating 6: Through hole 7: Through hole 8 after circuit formation: Circuit 9: Nickel / gold plating 10: Bending part 11: Interlayer Connection part a: three-dimensional structure

Claims (18)

  A printed wiring board comprising: a rigid support having a concavo-convex structure portion; a resin coating portion formed at least on the concavo-convex structure portion; and a circuit formed on at least the resin coating portion by conductor plating.   The printed wiring board according to claim 1, wherein the resin is a thermosetting resin.   The printed wiring board according to claim 1, wherein the resin is a thermoplastic resin.   The printed wiring board according to claim 1, wherein the support is a conductive substrate.   The printed wiring board according to claim 4, wherein the conductive substrate is made of a metal sheet or a metal foil.   6. The printed wiring board according to claim 1, wherein the concavo-convex structure portion of the support is an interlayer connection portion.   The printed wiring board according to claim 1, wherein the support is an insulating substrate.   The printed wiring board according to claim 7, wherein the insulating substrate is made of ceramics.   A step of forming a concavo-convex structure portion on a rigid support, a step of forming a resin coating portion on at least the concavo-convex structure portion of the support, a step of conducting conductor plating on the entire surface including the resin coating portion, and the conductor plating. And a process for forming a circuit.   The method for manufacturing a printed wiring board according to claim 9, wherein the resin coating portion is formed by an injection molding machine.   The method for producing a printed wiring board according to claim 9 or 10, wherein the resin is a thermosetting resin.   The method for producing a printed wiring board according to claim 9 or 10, wherein the resin is a thermoplastic resin.   The method for manufacturing a printed wiring board according to claim 9, wherein the support is a conductive substrate.   The method for producing a printed wiring board according to claim 13, wherein the conductive substrate is made of a metal sheet or a metal foil.   The method for producing a printed wiring board according to any one of claims 9 to 14, wherein the concavo-convex structure portion of the support is formed by bending, punching, crushing, or drawing.   The method for manufacturing a printed wiring board according to any one of claims 9 to 14, wherein the concavo-convex structure portion of the support is formed by etching or laser processing.   The method for producing a printed wiring board according to any one of claims 9 to 16, wherein the uneven structure portion of the support is used as an interlayer connection portion.   The method for producing a printed wiring board according to any one of claims 9 to 17, wherein the uneven structure portion of the support is used as a component mounting pad or a land.