JP4151503B2 - Circuit board manufacturing method - Google Patents

Description

  The present invention relates to a continuous processing method at the time of forming a circuit and a method for cutting an edge of a plating power feeding part in a three-dimensional circuit board such as MID (Molded Interconnect Device) in which an electric circuit is formed on the surface of a molded product.

  Conventionally, a metal thin film is formed on a substrate as a conductor for forming a circuit, and a non-circuit portion of the metal thin film is removed by a laser, or at least a contour portion of the non-circuit portion is removed to insulate the circuit. A method for manufacturing a printed circuit board is known in which after a circuit is electrically insulated, a metal thin film pattern of a circuit portion is electroplated to form a circuit pattern. In this circuit board manufacturing method, a metal thin film, for example, a copper thin film, is formed on a base material by sputtering, and then the contour of the non-circuit portion is removed using a laser. Copper plating is performed to increase the thickness of the copper layer to form a circuit pattern, and then the thin metal layer of the non-circuit portion is removed by soft etching, and then the circuit pattern is subjected to electro nickel plating or gold plating. A final circuit pattern is formed. In this manufacturing method, since the circuit pattern can be obtained even if the base material is not flat, a three-dimensionally formed wiring board (MID board) that forms a three-dimensional circuit path pattern on the three-dimensionally formed base material. Is used extensively. In such a manufacturing method, the entire circuit pattern is connected to the power supply electrode for power supply for electroplating. In view of this, a method has been adopted in which a sheet-like molded product in which a plurality of individual pieces are collected is cut after circuit formation, and a feeding portion is cut off to obtain desired pieces (for example, Patent Document 1). reference).

In addition, a method of manufacturing a circuit board using a lead frame as a power feeding circuit and a carrier is known instead of the above-described sheet-like molded product for power supply for electroplating (see, for example, Patent Document 2).
JP 2001-345533 A Japanese Patent Laid-Open No. 2003-068925

  However, the circuit board manufacturing method as described in Patent Document 1 described above has the following problems. That is, it is necessary to perform a cutting process in order to cut the feeding circuit portion. Also, since the circuit board has a three-dimensional shape, unlike cutting on a flat board, it cannot be easily cut. For example, a special cutting method such as cutting after fixing a work packed in ice Is required and the processing cost is high. Furthermore, in a sheet-like molded product in which a plurality of pieces are collected, warping of the sheet often occurs, and it is difficult to maintain the pitch accuracy of the pieces with high accuracy. It is difficult to secure.

  Further, in the method of manufacturing a circuit board as shown in Patent Document 2 described above, a lead frame is used as a power feeding portion, and the surface-to-surface intersection portion from the surface of the lead frame to the surface of the resin molded product However, a gap may occur at the joint between the molded resin and the lead frame due to the shrinkage of the resin or the difference in linear expansion coefficient after insert molding, and disconnection is likely to occur at the plane crossing portion. There is a problem. Further, the plating solution may enter from the gap between the molded product resin and the lead frame to cause corrosion or adversely affect electronic components.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and with a simple configuration, power supply for plating a circuit board can be ensured, and a circuit board manufacturing method and method for improving processing quality and circuit formation efficiency can be achieved. It aims at providing the circuit board by.

  In order to achieve the above object, the invention of claim 1 is characterized in that a lead made of a conductive flat plate is placed in a mold, and a liquid or powder resin is injected into the mold and cured to join the lead. A substrate forming step for forming an insulating substrate, a circuit pattern forming step for forming a desired circuit pattern on the surface of the insulating substrate formed by the substrate forming step so as to be electrically connected to the leads, and the circuit pattern After the forming step, a circuit forming step in which electroplating is performed by supplying power to the circuit pattern through the leads, and after the circuit forming step, the leads are separated from the insulating substrate bonded to the leads at the joints. And a lead separation process.

According to a second aspect of the present invention, in the method for manufacturing a circuit board according to the first aspect, in the substrate forming step, the convex portion is formed by using a lead having a convex portion perpendicular to the main plane of the conductive flat plate material. molding the substrate in a shape penetrating the insulating substrate, when the lead separation step, the main plane perpendicular direction of the lead to the lead or insulating substrate in which the separation by applying a force.

  According to a third aspect of the present invention, in the method for manufacturing a circuit board according to the second aspect, in the substrate forming step, the convex portion is positioned near the central portion in the mold and the lead is disposed.

  According to a fourth aspect of the present invention, in the method of manufacturing a circuit board according to any one of the first to third aspects, the joint between the lead and the insulating substrate is locally heated before the lead separation step. .

According to a fifth aspect of the present invention, in the method for manufacturing a circuit board according to any one of the first to third aspects, the length of the joint portion between the lead and the insulating substrate is 0.1 mm to 1. A lead of 0 mm is used.

  According to a sixth aspect of the present invention, in the method for manufacturing a circuit board according to any one of the first to third aspects, the insulating substrate in the vicinity of the interface exposed portion of the joint between the lead and the insulating substrate during the substrate forming step. An insulating substrate having a taper shape in which the cross-sectional shape becomes thinner along the lead surface is formed.

  According to a seventh aspect of the present invention, in the method for manufacturing a circuit board according to any one of the first to third aspects, a circuit pattern on the surface of an insulating substrate connected to the lead is applied to the lead in the circuit forming step. In the vicinity of the connecting portion, the width is locally narrowed.

  According to an eighth aspect of the present invention, in the method for manufacturing a circuit board according to any one of the first to third aspects, the circuit pattern on the surface of the insulating substrate connected to the leads is provided before the lead separation step. Cutting is performed in the vicinity of the lead.

  According to a ninth aspect of the present invention, in the method for manufacturing a circuit board according to the eighth aspect, a laser is used for cutting the circuit pattern.

  According to a tenth aspect of the present invention, in the method for manufacturing a circuit board according to any one of the first to third aspects, before the electroplating in the circuit forming step, the circuit pattern on the surface of the insulating substrate to be connected to the lead is formed. A plating prevention mask is provided in the vicinity of the lead.

  According to an eleventh aspect of the present invention, in the method for manufacturing a circuit board according to any one of the first to third aspects, before the circuit forming step, a filler is applied to an exposed portion of the interface between the lead and the insulating substrate. Is applied.

  According to the first aspect of the present invention, the lead made of the conductive flat plate material is arranged in the mold, the insulating substrate bonded to the lead is formed, and the desired circuit pattern is electrically connected to the lead on the surface of the insulating substrate. It is formed so that it is connected to the circuit pattern, power is supplied to the circuit pattern through the lead, electroplating is performed, and then the lead is separated from the insulating substrate at the joint, so that cutting processing from the circuit board is not used. The lead as the power supply electrode can be removed with good work efficiency and good processing quality, and the plating power supply portion can be cut off. In addition, since the lead of the power supply electrode does not remain on the circuit board, a corrosive substance such as a plating solution does not remain in the gap between the lead insert portions, and a circuit board with high processing quality can be obtained.

According to a second aspect of the present invention, a lead having a convex portion perpendicular to the main plane of the lead is used, and the substrate is formed into a shape in which the convex portion penetrates the insulating substrate. since by applying a main plane and a direction perpendicular to the force of the lead substrate to separate the lead and the insulating substrate, it is possible to punch the convex portion of the lead into the through direction, compared with the pressing of a conventional dicing and lead Thus, it is possible to efficiently separate the feeding electrodes, and the processing efficiency (manufacturing efficiency) is improved.

  According to the invention of claim 3, since the lead is disposed and the resin is molded by positioning the convex part in the vicinity of the central part in the mold, the convex part of the central part and the insulating substrate are formed by molding shrinkage of the resin. The bonding between the two becomes strong, the generation of a gap at the bonding portion is suppressed, the feeding circuit is not cut, and reliable electroplating is possible.

  According to the invention of claim 4, since the joint between the lead and the insulating substrate is locally heated and the resin insulating substrate is softened at the joint, both can be separated. And the occurrence of chipping in the insulating substrate can be suppressed.

In addition, according to the invention of claim 5, since the lead having a joint length of 0.1 mm to 1.0 mm is used between the lead and the insulating substrate, the appropriate joint length can cause a problem or plating at the time of separation. Time trouble can be reduced. That is, if the joint length is too long, a large force is required at the time of separation, and the insulating substrate may be chipped, and if it is too short, the lead may fall off from the insulating substrate during electroplating or transportation. However, by using the length of the joint portion, it is difficult to cause such a problem of chipping or dropping.

  According to a sixth aspect of the invention, there is provided an insulating substrate having a tapered shape in which the cross-sectional shape of the insulating substrate in the vicinity of the exposed portion of the interface between the lead and the insulating substrate is thin along the lead surface. Because it is molded, the surface of the lead, which is the feeding electrode, and the conductor layer surface of the circuit pattern formed on the insulating substrate intersect at an obtuse angle, the connection of the surface becomes smooth, for example, the formation of a conductor thin film by sputtering is uniform Thus, the thickness can be formed without any discontinuous portions, and disconnection of the power supply current circuit hardly occurs. Also, when separating the leads from the insulating substrate, the circuit pattern on the insulating substrate is cut due to stress concentration at the tip of the thin part, so the circuit pattern in the vicinity of the joint after separation of the leads has no burr or turning A board is obtained.

  According to the invention of claim 7, since the circuit pattern on the surface of the insulating substrate connected to the lead is formed with a locally narrow width in the vicinity of the connecting portion to the lead, the lead is separated from the insulating substrate. In this case, it is possible to easily cut the circuit pattern at a portion where the width is locally narrowed. Therefore, it is possible to prevent the circuit in the vicinity of the joint portion of the insulating substrate from being pulled by the lead during separation.

  According to the invention of claim 8, since the circuit pattern on the surface of the insulating substrate connected to the lead is cut in the vicinity of the lead before the separation of the lead, the circuit pattern in the vicinity of the joint portion of the insulating substrate is peeled off. Can be prevented.

  According to the invention of claim 9, since the laser is used for cutting the circuit pattern, the circuit pattern can be easily cut even with a three-dimensional insulating substrate, and the same effect as described above can be obtained.

  According to the invention of claim 10, since the plating prevention mask is applied in the vicinity of the lead of the circuit pattern on the surface of the insulating substrate connected to the lead for power feeding before the electroplating, the portion covered with the mask The plating pattern is not formed and the circuit pattern remains in a thin state, and when the lead is separated from the insulating substrate, it is cut at the thin circuit pattern portion, and the circuit pattern in the vicinity of the joint portion does not peel off, A circuit board with good processing quality can be obtained.

  According to the eleventh aspect of the present invention, since the filler is applied to the exposed portion of the interface between the lead and the insulating substrate before the circuit pattern is formed, the gap between the lead and the insulating substrate is filled and insulated from the lead. In the case where the surface of the conductive substrate is made smoothly continuous and a conductive thin film is formed on the surface by, for example, sputtering film formation, the continuous conductive thin film is formed to reduce problems caused by disconnection of the plating power supply circuit.

  A circuit board manufacturing method and a circuit board according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a circuit board according to the present invention and its usage. As shown in FIGS. 1 (a1) and (a2), the circuit board 1 has, for example, a substantially rectangular parallelepiped shape, and has a recess 11 for mounting an electronic element on one surface (referred to as an upper surface). ing. The external dimension of the circuit board 1 is 5-15 mm, for example. On the back surface of the circuit board 1, there is a concave portion 10 that terminates on the side surface. In the case of the circuit board 1, the concave portion 10 is formed in such a manner that it is interposed between the side surfaces facing each other. The circuit pattern 2 is formed on the side surface where the recess 10 terminates in a manner that continues to the bottom surface of the recess 10. The circuit pattern 2 is three-dimensionally drawn from the outer wall surface of the circuit board 1 to the inner wall surface and terminates in the recess 11.

  As shown in FIG. 1B, an electronic element 12 is mounted in the recess 11, and the electronic element 12 is electrically connected to the circuit pattern 2 by a bonding wire 13 such as a gold wire. The circuit board 1 on which the electronic elements are mounted is sealed with a sealing resin 14 as shown in FIG. As shown in FIG. 1D, the circuit board 1 on which the electronic elements are mounted and resin-sealed is opposed to the circuit pattern 151 on the printed board 15 so that the circuit pattern 2 on the circuit board 1 and the printed circuit board 1 are printed. The circuit pattern 155 of the substrate 15 is electrically connected by solder 155 and mounted on the printed circuit board 15. The circuit board 1 is a three-dimensional circuit board used as a package or the like for surface mounting electronic elements on the printed circuit board 15 or the like such as a capacitor 153. The three-dimensional circuit board is formed by, for example, a MID (Molded Interconnect Device) forming method.

The recess 10 in the circuit board 1 will be described. FIG. 2 shows the final stage of the process of forming the circuit pattern 2 on the circuit board 1. Circuit board 1, as shown in FIG. 2 (a) (c), in the final stage of forming the circuit pattern 2, and a power supply lead 301 for electroplating on the back. The lead 301 from circuit board 1, and separated as shown in FIG. 2 (b) (d), the concave portion 10 as shown in FIG. 2 (d) is formed as a trace of the lead 301.

  In this way, the circuit is formed by electroplating without cutting the power supply lead 301 for electroplating and without processing the circuit board body for cutting the power supply circuit to the circuit board 1. Obtaining a circuit board on which a pattern is formed is one of the features of the circuit board of the present invention and its manufacturing method. According to the present invention, the lead can be removed efficiently, and the lead of the power supply electrode does not remain on the circuit board, so that a corrosive substance such as a plating solution does not remain in the gap between the lead insert portions. A high circuit board is obtained.

  Next, an outline of the circuit board manufacturing process will be described. FIG. 3 shows a manufacturing flow. First, in the substrate molding step (S1), a lead for power supply for electroplating is placed in a mold, and an insulating substrate bonded to the lead is molded by injecting a liquid or powder resin into the mold and curing it. To do.

  Subsequently, in the circuit pattern forming step (S2), the surface of the insulating substrate is metallized, and a desired circuit pattern is formed on the metallized layer so as to be electrically connected to the leads. In other words, a circuit portion connected to the lead and a non-circuit portion insulated from the lead are formed.

  Subsequently, in a circuit formation step (S3), a circuit pattern serving as a circuit portion is supplied with power through a lead and electroplating is performed to form a circuit pattern thickened to a predetermined pattern thickness. Thereafter, surface treatment such as gold plating is performed as necessary, and the thin metallized layer of the non-circuit portion is removed by etching.

  Subsequently, in the lead separation step (S4), the three-dimensional circuit board on which the three-dimensional circuit pattern is formed is obtained by separating the insulating substrate bonded to the lead from the lead.

  Next, the circuit board manufacturing process will be described in order. FIG. 4 shows a circuit board manufacturing process according to a plan view. First, as shown in FIG. 4A, a lead frame 3 having a lead 301 for electroplating is prepared. As a material of the lead frame 3, for example, a metal hoop material (conductive plate material) such as copper, phosphor bronze, brass, nickel, 42 alloy is used. The thickness of the metal hoop material is, for example, 0.1 mm to 0.5 mm. A pilot hole 302 for positioning, a lead 301 as a power feeding pattern portion, and the like are formed by pressing or etching the metal hoop material. The lead frame 3 shown in the drawing is shown by extracting two pattern portions from a belt-like lead frame in which the same pattern is repeated on the left and right sides. In the manufacturing process, the lead frame 3 has a function as a carrier in addition to the function of the power feeding electrode.

  Subsequently, as shown in FIG. 4B, the lead 301 is subjected to a surface treatment so that the lead 301 and the molding resin are brought into close contact with each other. As the treatment, treatment with coupling materials such as amino silane and imidazole silane, organic plating treatment using triazine thiol salt, polyimide coating treatment, surface roughening with liquid such as ferric chloride, phoscoat, CPE, etc. Processing etc. are suitably performed.

  Subsequently, as shown in FIG. 4C, the insulating substrate 101 is resin-formed as an MID substrate. As the resin, liquid crystal polymer, polyphthalamide, polyphthalsulfone, epoxy, SPS, PBT or the like is used. For the molding, injection molding, transfer molding, or the like is used. After the lead 301 of the lead frame 3 is inserted, the molding is performed.

  Subsequently, as shown in FIG. 4D, a conductive film made of a copper thin film serving as a plating base layer is formed on the surface of the insulating substrate 101 and the leads 301 by using vacuum deposition, DC sputtering, RF sputtering, or the like. 42 is formed. The film thickness of the conductive film 42 is, for example, 0.3 μm.

  The plating base layer on the surface of the insulating substrate 101 may be formed at least in a region where a circuit pattern is to be formed and a region where the circuit pattern is electrically connected to the lead frame 3 which is a power supply electrode for electroplating. For example, when a circuit pattern is formed only on the upper portion excluding the back surface of the insulating substrate 101 formed on the upper surface side of the lead frame 3, it is necessary to form a plating base layer on the back surface of the insulating substrate 101. Absent. If an unnecessary plating base layer is formed on the back surface of the insulating substrate 101, a region where the non-circuit region and the lead frame 3 are electrically connected increases, and a new effort to insulate and separate them occurs. .

  Subsequently, as shown in FIG. 4E, the surface of the MID substrate on which the conductive film is formed is irradiated with an energy beam such as a laser to evaporate and remove the irradiated copper thin film. As this laser, a laser that is easily absorbed by the conductive film (plating base film), such as second and third harmonic YAG lasers and YAG lasers, is preferable because of its high removal efficiency. By scanning the laser with a galvanometer mirror, a linear insulating space 201 is formed along the outer periphery of the circuit pattern region 200, and the circuit pattern region 200 is insulated from the non-circuit region 202. The circuit pattern region 200 is electrically connected to the lead 301, and the non-circuit region 202 is insulated from the lead 301 and the circuit portion region 200. Therefore, the linear insulating space 201 is formed by scanning with a laser so as to surround the lead 301 (and the circuit pattern region 200) at the joint between the lead 301 and the insulating substrate 101.

  Subsequently, by supplying power to the circuit pattern region through the lead frame 3, as shown in FIG. 4F, for example, copper plating 43 is performed only on the region. The plating configuration and plating thickness are not limited, and plating other than copper plating can also be performed. If necessary, nickel, silver, gold, etc. can be formed in multiple layers. Thereafter, the plating base film in the non-circuit region is removed by soft etching or the like.

  Subsequently, as shown in FIG. 4G, the lead 301 and the circuit board 1 are separated at the joint portion. By this separation, the circuit patterns 2 are automatically electrically insulated from each other, and a desired circuit board 1 is obtained.

  Next, separation of leads and circuit boards will be described. FIG. 5 shows a lead separation process. The circuit board 1 shown in FIG. 5A is the same as that described above. As a method of separating the lead 301 from the circuit board 1 after a circuit formation process such as electroplating, the lead 301 can be separated by simply applying a force in a direction in which both are separated. Separation is performed as follows in order to make the circuit board 1 after separation free from burrs, chipping, warping, and the like, and to make the circuit board of higher quality and easy to separate. That is, after the lead 301 is heated to soften the molding resin, the lead 301 is separated from the circuit board 1.

  The lead 301 is heated by sandwiching the lead 301 from both sides using heater blocks 541 and 542 in which the cartridge heater 56 is embedded, as shown in FIG.

  The upper heater block 542 is vertically movable and fixes the lead 301 when the lead 301 is heated and when the circuit board 1 is separated. The circuit board 1 is gripped by a chuck 55 that can be opened and closed and moved up and down from above. At the time of separation of the circuit board 1, the chuck 55 grasps the circuit board 1 and rises, and the circuit board 1 is pulled upward from the lead 301. The overall operation flow is, for example, that the circuit board 1 and the lead frame are set in the lower heater block 541 → the upper heater block 542 is lowered to clamp the lead 301 → the heater 56 is turned on → the chuck 55 is lowered and the circuit board 1 is lowered. The chuck 55 is lifted, the circuit board 1 is transferred, the heater 56 is turned off, the upper heater block 542 is lifted, and the lead frame 3 is forwarded.

  Separation of the circuit board 1 may be performed on a plurality of circuit boards at the same time, and the heating temperature of the lead 301 is desirably a temperature that is about 10 to 30 ° C. higher than the glass phase transition temperature (Tg) of the molding resin. Further, since the thermal conductivity of the molding resin forming the circuit board 1 is much smaller than the thermal conductivity of the lead 301, the circuit board 1 is only locally heated when the lead 301 is heated. Separation is carried out without causing heat damage to the main part. By softening the molding resin and weakening the adhesion with the leads 301, the force required for separation can be reduced, and the occurrence of chipping of the circuit board 1 can be suppressed during separation.

  Next, another example of the circuit board and the manufacturing method thereof will be described. FIG. 6 shows a circuit board manufacturing method using a lead frame having a convex portion having a shape different from that of the lead frame described above. As shown in FIGS. 6A to 6C, the lead frame 3 has convex portions 313 and 315 substantially perpendicular to the main plane of the conductive flat plate material forming the lead frame 3, and the convex portion 313. , 315 are formed in a shape penetrating the circuit board 1. Therefore, the circuit board 1 separated from the leads 312 and 313 has through holes 330 and 350 as shown in FIG.

  The convex portions 313 and 315 of the lead frame 3 are formed by bending the tips of the leads 312 and 314 so as to be exposed through the circuit board 1 on the center line of the circuit board 1, for example. Power supply for plating on the circuit patterns 203 and 205 is performed through convex portions 313 and 315 exposed at the center of the circuit board 1.

  Resin shrinkage at the time of molding shrinks in the direction of the approximate center of gravity of the molded body, so that the convex portions 313 and 315 that are passed through and exposed to the substantially central portion of the circuit board 1 and the peripheral resin are firmly adhered by the resin shrinkage force. Join. Therefore, the generation of a gap at the joint is suppressed, and the power supply circuit is not cut off, thereby enabling reliable electroplating. There may be a plurality of such penetrating / exposed leads depending on the shape of the circuit pattern and the shape of the circuit board itself. Further, the surface treatment for improving the adhesion of the lead frame before the insert molding as shown in FIG.

  The separation of the lead frame having the convex portion and the circuit board will be described. FIG. 7 shows the state before and after separation. As shown in FIG. 7A, the protrusion 315 of the lead 314 exposed on the center surface of the circuit board 1 is separated from the main plane of the lead 314 (left and right in the figure) in a direction (in the figure). For example, the punch 53 is punched from top to bottom along the vertical direction. As shown in FIG. 7B, the circuit board separated from the leads 312 and 314 is formed with a through hole 350 after the protrusion 315 is removed, and the circuit pattern 205 is left and right by the through hole 350. The circuit patterns 205 are separated from each other and electrically insulated from each other.

  Next, still another example of the circuit board and the manufacturing method thereof will be described. FIG. 8 shows a circuit board manufacturing method in which leads are joined to left and right side walls of a circuit board using a lead frame having a shape different from that of the above-described lead frame. As shown in FIG. 8A, electrical connection between the lead 320 and the circuit pattern 2 is performed by slightly inserting the tip portions 321 of the leads 320 into the left and right side walls of the circuit board 1 and through the side walls. Is called. The insertion depth, that is, the junction length d is set to a range of about 0.1 to 1.0 mm. That is, if the joint length is too long, a large force is required at the time of separation, and the insulating substrate may be chipped, and if it is too short, the lead may fall off from the insulating substrate during electroplating or transportation. However, by using the length of the joint portion, it is difficult to cause such a problem of chipping or dropping.

  As shown in FIGS. 8B and 8C, the lead 320 and the circuit board 1 are separated by pulling the lead 320 left and right. That is, when separating the leads, the leads 320 and the circuit board 1 are chucked in the same manner as shown in FIG. A plurality of circuit boards 1 may be separated at the same time. Further, in order to prevent the conductor film of the circuit pattern from being pulled and peeled off by the lead 320 when the lead is extracted, it is desirable to chuck the circuit board 1 with the circuit pattern sandwiched in the immediate vicinity of the lead 320.

  Next, still another example of the circuit board and the manufacturing method thereof will be described. FIG. 9 shows a method for manufacturing a circuit board having a thin taper at the joint with the lead. The cross-sectional shape of the insulating substrate 101 in the vicinity of the joint interface exposed portion between the lead 301 and the insulating substrate 101 includes a taper portion 17 whose thickness decreases along the surface of the lead 301. The surface of the lead 301 serving as the power supply electrode and the conductor layer surface of the circuit pattern 2 formed on the insulating substrate 101 intersect at an obtuse angle θ, and the connection between the surfaces is smooth. Therefore, for example, the conductor thin film can be formed by sputtering with a uniform thickness and without any discontinuous portion, so that disconnection of the power supply current circuit is less likely to occur.

  The lead 301 is separated by chucking the circuit board 1 with the chuck 55 and pressing the lead 301 downward with a jig 58 in the drawing. When the leads 301 are separated from the insulating substrate 101, the circuit pattern 2 on the insulating substrate 101 is not cut in a state having a peeled portion. This is because the circuit pattern 2 is cut by the stress concentration at the tip P of the tapered portion 17 of the thin portion, as shown in FIG. A circuit board having no burrs or turning over in the circuit pattern in the vicinity of the joint after separating the leads 301 is obtained.

  Next, still another example of the circuit board and the manufacturing method thereof will be described. FIG. 10 shows an example in which the circuit pattern at the junction with the lead is constricted. As shown in FIG. 10A, the circuit pattern 2 has a tapered shape 21 that becomes narrower toward the lead 301 at the joint portion between the lead 301 and the circuit board 1, and the width is locally narrowed. Pattern 2 is formed.

  In this way, when the lead 301 is separated from the circuit board 1, the circuit pattern 2 is cut at a portion where the width is locally narrowed as shown in FIG. A minute circuit portion existing around the lead 301 is attached to the lead 301 and separated from the circuit board 1 together with the lead 301. This is a phenomenon that occurs because the adhesion between the metal lead 301 and the plating film is higher than the adhesion between the molding resin of the insulating substrate and the plating film. Therefore, it is possible to prevent the circuit wave end 2 from being peeled off in the vicinity of the joint portion of the circuit board 1 due to the circuit pattern 2 being pulled by the lead 301 at the time of separation.

  Next, still another example of the circuit board and the manufacturing method thereof will be described. FIG. 11 shows an example in which a plating prevention mask 80 is provided at the joint between the lead 301 and the circuit pattern 2. When a plating prevention mask (resist) 80 is applied to the joint between the lead 301 and the circuit board 1 after the patterning process and then electroplating is performed, the plating current flows through the conductive film 42 which is the plating base film. For example, a copper plating 43 grows on the plating base film. However, no plating film grows on the surface of the plating prevention mask 80. Therefore, if the plating prevention mask 80 is peeled after plating, only the thin film at the time of metallization remains after the plating prevention mask 80 is peeled off. When the leads 301 are separated from the circuit board 1, the circuit pattern of the joint portion is thin. Since it is cut by (conductive film 42), the circuit pattern 2 in the vicinity of the joint is not peeled off, and a circuit board with good processing quality is obtained.

  Next, still another example of the circuit board and the manufacturing method thereof will be described. FIG. 12 shows an example of pre-processing in the circuit pattern forming process. When the lead frame is insert-molded to form the insulating substrate 101 on the lead 301, the joint portion 82 between the lead 301 and the insulating substrate 101 is formed by resin molding shrinkage as shown in FIG. A gap 83 may occur. Therefore, as shown in FIG. 12C, after filling and filling the gap 83 between the insulating substrate 101 and the lead 301 with a filler 84 made of a resin having good permeability such as an epoxy resin, Perform metallization processing.

  By performing such a pretreatment, as shown in FIG. 12D, a conductive film 42 serving as a plating base layer that continuously covers the surfaces of the leads 301 and the insulating substrate 101 can be formed. That is, when the metallization process is performed in the state shown in FIG. 12B, the problem that the conductive film 42 becomes discontinuous at the point Q shown in FIG. 12D can be avoided. Note that a silver paste using an epoxy resin can be used as the filler 84 so as to improve conduction.

  Next, still another example of the circuit board and the manufacturing method thereof will be described. FIG. 13 shows an example of mechanically cutting the circuit pattern in the vicinity of the joint before the separation step, and FIG. 14 shows an example of cutting with a laser. In FIG. 13, when the circuit board 1 and the lead 301 are separated, the circuit board 1 is sent between a slitter blade 60 having a sharp tip so that the circuit pattern 2 can be easily cut without causing peeling. Cut pattern 2 completely. In addition to the thickness of the circuit pattern 2, the slitter blade 60 cuts the molded product slightly so as to cut the circuit board 1 with a constant size or a constant pressure. Note that the slitter blade 60 rotates in accordance with the progressive feeding of the circuit board 1.

In FIG. 14, the circuit pattern 2 is cut in the same manner as described above, and a laser 70 is used for the cutting. The circuit board 1 is sequentially fed into a space facing the laser 70 and the circuit pattern 2 at the joint between the lead 301 and the circuit board 1 is laser-cut. As the laser 70, a laser similar to the laser used in the circuit pattern forming step, a CO ₂ laser, or the like is preferably used. By limiting the portion irradiated with the laser 70 to the portion where the circuit pattern 2 exists, the insulating substrate forming resin of the circuit board 1 can be prevented from being damaged as much as possible.

  Adjustment of the irradiated portion of the laser 70 may be performed by mechanically feeding the circuit board 1 or by scanning laser light with a galvano mirror. The strength of the laser 70 is adjusted so that the molded product is cut slightly in addition to the thickness of the circuit pattern. After the circuit pattern near the joint is cut by such a simple cutting method, the circuit pattern can be prevented from being peeled by separating the leads from the circuit board.

  The present invention is not limited to the above-described configuration, and various modifications can be made. In the example of the circuit board described above, the case where there are four circuit patterns is illustrated and described. However, the present invention can be applied to any other number of circuit patterns and shapes. In the embodiment, the case where the laser method is used as the circuit forming method has been described. However, the present invention can also be applied to a method of forming a circuit using a two-shot method or the like.

(A1)-(d) is a perspective view which shows the circuit board which concerns on one Embodiment of this invention, and its use condition. (A)-(d) is a perspective view explaining the isolation | separation process in a circuit board manufacturing process same as the above. The flowchart of the manufacturing process of a circuit board same as the above. (A)-(g) is a top view of the lead | read | reed and circuit board which illustrate the manufacturing process of a circuit board same as the above. (A) is a top view which shows the state before the isolation | separation process of a circuit board same as the above, (b) (c) is AA sectional drawing in (a) explaining the isolation | separation process of the circuit board in (a). (A) is a top view explaining the circuit board which shows the other example which concerns on one Embodiment of this invention, and its manufacturing method, (b) is BB sectional drawing in (a), (c) is (a). The top view of the lead | read | reed isolate | separated from the state shown to (d), (d) is the top view of the circuit board isolate | separated from the state shown to (a). (A) and (b) are the cross sections explaining the process of isolate | separating a lead and a circuit board from the state shown to Fig.5 (a). (A) is the top view before the circuit board isolation | separation process explaining the circuit board which shows further others concerning one Embodiment of this invention, and its manufacturing method, (b) (c) is isolation | separation of the circuit board in (a). CC sectional drawing in (a) explaining a process. (A) is the top view before the circuit board isolation | separation process explaining the circuit board which shows further others concerning one Embodiment of this invention, and its manufacturing method, (b) (c) is isolation | separation of the circuit board in (a). D-d sectional drawing in (a) explaining a process. (A) is the side view before the separation process of the circuit board explaining the manufacturing method of the circuit board which shows further others concerning one embodiment of the present invention, (b) explains the separation state of the circuit board in (a). Side view. (A) is the side view before the separation process of the circuit board explaining the manufacturing method of the circuit board which shows further others concerning one embodiment of the present invention, (b) is an EE sectional view of the circuit board in (a) . (A) is the side view before the circuit formation process of the circuit board explaining the manufacturing method of the circuit board which shows further others concerning one embodiment of the present invention, (b) is the FF section of the circuit board in (a) FIG. 4C is a cross-sectional view of a state in which a conductive thin film is formed on the circuit board in FIG. (A) is the top view before the isolation | separation process of the circuit board explaining the manufacturing method of the circuit board which shows further others concerning one Embodiment of this invention, (b) is FF sectional drawing of the circuit board in (a). . (A) is the top view before the isolation | separation process of the circuit board explaining the manufacturing method of the circuit board which shows further others concerning one Embodiment of this invention, (b) is GG sectional drawing of the circuit board in (a). .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board 2 Circuit pattern 3 Lead | read | reed 80 Anti-plating mask 101 Insulation board | substrate 315 Convex part d Junction length

Claims (11)

A substrate molding step of forming an insulating substrate bonded to the lead by placing a lead made of a conductive flat plate in the mold, and injecting and curing a liquid or powder resin in the mold;
A circuit pattern forming step of forming a desired circuit pattern on the surface of the insulating substrate formed by the substrate forming step so as to be electrically connected to the leads;
After the circuit pattern forming step, a circuit forming step of performing electroplating by supplying power to the circuit pattern through the leads;
A method of manufacturing a circuit board, comprising: a lead separation step of separating the leads from the insulating substrate joined to the leads at the joint after the circuit formation step. During the substrate molding step, using a lead having a projection perpendicular to the main plane of the conductive flat plate, the projection is molded into a shape penetrating the insulating substrate,
2. The method of manufacturing a circuit board according to claim 1, wherein, in the lead separation step, the lead or the insulating substrate is separated by applying a force in a direction perpendicular to a main plane of the lead.   3. The method of manufacturing a circuit board according to claim 2, wherein, in the substrate forming step, the lead is disposed with the convex portion being positioned in the vicinity of a central portion in the mold.   4. The circuit board manufacturing method according to claim 1, wherein a joint portion between the lead and the insulating substrate is locally heated before the lead separation step. 5.   The circuit board according to any one of claims 1 to 3, wherein a lead having a joint length of 0.1 mm to 1.0 mm between the lead and the insulating substrate is used in the substrate forming step. Production method.   Forming an insulating substrate having a tapered shape in which the cross-sectional shape of the insulating substrate in the vicinity of the interface exposed portion of the joint between the lead and the insulating substrate is thinned along the lead surface during the substrate forming step; The method for manufacturing a circuit board according to claim 1, wherein the circuit board is a manufacturing method of the circuit board.   4. The circuit pattern on the surface of the insulating substrate connected to the lead is formed with a locally narrow width in the vicinity of the connection portion to the lead during the circuit forming step. A method for producing a circuit board according to any one of the above.   4. The circuit board according to claim 1, wherein the circuit pattern on the surface of the insulating substrate connected to the lead is cut in the vicinity of the lead before the lead separation step. 5. Manufacturing method.   The method for manufacturing a circuit board according to claim 8, wherein a laser is used for cutting the circuit pattern.   The plating prevention mask is applied to the vicinity of the lead of the circuit pattern on the surface of the insulating substrate connected to the lead before electroplating in the circuit forming step. Production method.   The method for manufacturing a circuit board according to claim 1, wherein a filler is applied to a joint interface exposed portion between the lead and the insulating substrate before the circuit pattern forming step. .

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