JP2008244199A - Method for manufacturing metal core circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate generation of a defective product by disabling generation of short-circuit even if burrs are generated in the process of external shape of a double-sided wiring circuit board on which circuit patterns are formed on both surfaces. <P>SOLUTION: In the method for manufacturing a metal core circuit board, after a material to be processed 41 on which insulating layers 21a, 21a are laminated on both surfaces of a metal core 11 and a circuit pattern 31b is formed on these insulating layers is obtained, the external shape process is conducted to a base material 43 forming a product from the material to be processed 41 by shearing due to relative movement between a die and a punch. Moreover, the external shape process is conducted to the surface, as the die or punch contact surface, where the circuit pattern 31b is not provided at the area near the internal circumference of a virtual shearing line 44 showing a shearing position, among the front and rear surfaces of the part corresponding to the base material 43 in the material to be processed 41. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a metal core substrate in which outer shape processing is performed by punching with a die and a punch, and more particularly to a method for manufacturing a metal core substrate suitable for a double-sided wiring substrate having circuit patterns formed on both sides.

  In a metal core substrate having circuit patterns on both sides, insulating layers made of epoxy or the like are formed on both sides of a metal core made of copper or aluminum, and circuit patterns are formed on these insulating layers. The outline of the manufacturing process will be explained. First, a laminating process for laminating to provide insulating layers on both sides of the metal core, a drilling process for drilling holes such as through holes at predetermined positions of the laminated laminate, and a predetermined on the laminate A circuit pattern forming process for forming the circuit pattern and a resist coating process for protecting the surface and preventing the solder from adhering to unnecessary portions, and for a board (workpiece) formed through these processes. Thus, the metal core substrate is manufactured by performing external processing for separating the substrate material to be a product into circuit patterns.

  However, since the substrate material is separated from the metal core substrate by a shear using a press mold, there is a difficulty in generating burrs from the metal core. The burr is the remaining part of the material that occurs in the final stage of shearing by the die and punch, and can be formed on the side that hits the corner of the die or punch. In extreme cases, the length may protrude from the surface of the insulating layer laminated on the metal core.

  Since the resist is applied to the surface as described above, if the resist is applied normally, there is a metal core burr by punching, and even if the burr protrudes from the surface, the burr and circuit pattern are There is little risk of contact and short circuit. However, leakage along the creepage due to surface moisture absorption and condensation is considered. In addition, in the unlikely event that the resist is not normally applied as desired, or in a land where the resist is not applied, there is a possibility of causing a short circuit.

  In addition, although it is not a metal core board | substrate, there exists a technique in which generation | occurrence | production of the burr | flash was considered like the following patent document 1. FIG. In Patent Document 1, in a semiconductor integrated circuit device in which the size of the semiconductor chip is larger than the size of the die pad of the lead frame, the die pad is punched from above with the chip mounting surface facing upward in order to eliminate chip mounting defects. The burr is formed on the back side of the chip mounting surface, and the burr is prevented from contacting the chip. However, this technique does not consider the occurrence of short circuits.

  Moreover, in the metal core substrate, the possibility of short-circuit due to burrs has not been considered so far.

JP 2002-329829 A

  Therefore, the main object of the present invention is to eliminate the possibility of occurrence of a short circuit and avoid the occurrence of defective products even if burrs occur in the external processing of a double-sided wiring board having circuit patterns formed on both sides. .

  For this purpose, insulating layers are laminated on both surfaces of the metal core, and after obtaining a workpiece on which circuit patterns are formed on these insulating layers, a base material to be a product is die-molded from the workpiece. Is a method of manufacturing a metal core substrate that performs punching by shearing by the relative movement of a punch and a punch, and is an inner circumference of a virtual shear line that is a position where shearing is performed on both the front and back surfaces of the part corresponding to the substrate material in the workpiece This is a method for manufacturing a metal core substrate in which outer shape processing is performed using a surface having no circuit pattern in the vicinity of the side as an abutting surface that contacts a die or punch. The contact surface to be applied to the die or punch has a long distance between the surface opposite to the surface having the shortest distance between the virtual shear line and the circuit pattern, or between the virtual shear line and the circuit pattern. It is good to set it to the surface where the ratio with a part is high.

  When shearing with a die and a punch, burrs of the metal core occur on the side that hits the die and the side that hits the punch, but there is no circuit pattern in the vicinity of the inner peripheral side of the virtual shear line on the side where the burr occurs. The possibility of occurrence of a short circuit can be eliminated. Further, since there is no circuit pattern in the vicinity of the portion where burrs are generated, the possibility of occurrence of a short circuit can be eliminated even when the resist coating is not properly performed.

  As described above, according to the present invention, even if burrs are generated, there is no circuit pattern in the vicinity of the burrs, so the risk of short circuit can be eliminated. For this reason, in the final stage of manufacture, the occurrence of a defective product is not inadvertently caused, and a product with high quality and stable quality can be provided.

  The purpose of eliminating the possibility of short-circuiting due to metal core burr protrusion in the outer shape processing of the metal core substrate and avoiding the occurrence of defective products has been realized with the configuration of punching and circuit pattern.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing a process before external processing in a manufacturing process of a metal core substrate. The outline processing will be described after the outline will be described with reference to FIGS.

  As a material of the metal core 11, a rectangular metal plate made of copper or aluminum (hereinafter referred to as “base material 12”) is used (a).

  The metal core 11 is obtained by mechanically making holes 13 in the base material 12 (see FIG. 2), and performing a degreasing process such as washing with water, followed by roughening to roughen the surface (b).

  Next, the resin sheet 21 (for example, prepreg like FR-4) and the electrolytic copper foil 22 are disposed on both surfaces of the metal core 11. The resin sheet 21 is on the metal core 11 side, and the electrolytic copper foil 22 is on the front side (c).

  In this state, heat is applied and pressing is performed while evacuating, and the resin in which the resin sheet 21 is melted is injected and filled into the holes 13 of the metal core 11. When the resin is solidified, it becomes a single laminated plate 31 in which insulating layers 21a are formed on both surfaces of the metal core 11 (d).

  Thereafter, a through hole 31a having a smaller diameter than the hole 13 of the metal core 11 and penetrating in the thickness direction is opened in the resin filling portion of the laminated plate 31 (e).

  Subsequently, a copper plating layer 32 is formed on the electrolytic copper foil 22 located on the surface. A layer formed of the copper plating layer 32 and the electrolytic copper foil 22 is a circuit pattern 31b (f).

  A predetermined portion on the circuit pattern 31b is covered with a mask 33 (g), and a portion of the circuit pattern 31b not covered with the mask 33 is removed (h).

  Thereafter, the mask 33 is removed (i), and a solder resist 34 for internal protection is formed at a predetermined portion of the surface (j).

  Subsequently, the outer shape is processed as shown in FIG. That is, the substrate material 43 is obtained by punching each circuit pattern 31b so as to cut off the unnecessary portion 42 from the workpiece 41 obtained as shown in FIGS. A virtual line in FIGS. 2 and 3 is a virtual shear line 44 that is a position where punching is performed. Finally, a coating such as a preflux or a solder leveler is appropriately applied to complete the substrate material 43 as a metal core substrate.

The external shape processing is performed using a press die 51 as shown in FIG.
The press die 51 is moved up and down along the stripper 54 beside the stripper 54, a punch 53 fixed on the lower plate 52, a stripper 54 disposed above the punch 53 across the workpiece 41. And a stripper 56 disposed below the die 55 with the workpiece 41 interposed therebetween. Since the circuit pattern layer 31b exists within a range between the punch 53 and the stripper 54 in the workpiece 41, the punch 53 and the stopper 54 are provided with spaces 53a and 54a for escape.

  In such a press die 51, the workpiece 41 can be punched by placing the workpiece 41 on the punch 53, sandwiching the workpiece 41 with the stripper 54, and pressing down the die 55 positioned beside the stripper 54. At this time, between the punch 53 and the die 55, a gap (external shape processing gap c) is required as shown in FIG. 5 in order to protect the press die and appropriately shear.

At the time of punching, first, the outer shape machining gap c is set.
The outer shape processing gap c is set so as to suppress the occurrence of burrs 11a (see the phantom line in FIG. 5) of the metal core 11, but in addition to the burrs 11a, “done” 11b (see the phantom line in FIG. 5). ) Is also preferably suppressed. The “sag” 11b is generated when the die 55 and the punch 53 are sandwiched and crushed, and the corner portion of the surface of the metal core 11 opposite to the die 55 or the punch 53 is curved or inclined. . This is because the portion where the “sag” 11b is generated is a portion separated from the insulating layer 21a, and if the “sag” 11b increases, delamination (delamination) may occur. In addition, 11c shown by the virtual line in FIG. 5 is a shear surface, 11d is a torn surface.

  The external processing gap c that suppresses the generation of both the burr 11a and the “sag” 11b is smaller than the appropriate gap determined based on the material and thickness of the metal core 11, and is determined based on the material and thickness of the insulating layer 21a. Set to a value larger than the appropriate clearance.

  Each of the above-mentioned proper gaps is a gap that enables ideal shearing so that the end face after processing is relatively clean, and an approximate value can be found by a known method based on the material and thickness. From these values, the burr 11a and the “sag” 11b of the metal core 11 are suppressed to an allowable size within a range that is smaller than the appropriate gap value of the metal core 11 and larger than the appropriate gap value of the insulating layer 21a. Is set.

  In setting, the degree of difference in material and thickness of the metal core 11 and the insulating layer 21a is taken into consideration.

  Specifically, the value of the external processing clearance c is an intermediate value between the appropriate clearance determined based on the material and thickness of the metal core 11 and the appropriate clearance determined based on the material and thickness of the insulating layer 21a. It can be obtained by making corrections based on the material and / or thickness of the metal core 11 and the material and / or thickness of the insulating layer 21a. The correction is performed, for example, so that the insulating layer 21a is smaller than the intermediate value if the thickness is large, and is larger than the intermediate value if the thickness is small. This is because the shearing force applied to the insulating layer 21a at the time of shearing does not act on the metal core 11 at the same position, but is refracted by the difference in hardness between the insulating layer 21a and the metal core 11, particularly at the interface portion. It seems that this is because a phenomenon similar to the above occurs, and the shearing force applied from the die 55 and the punch 53 is shifted in the separating direction. The thicker the insulating layer 21a and the softer the material of the insulating layer 21a, the greater the deviation.

  From such a point of view, a 0.4 mm thick copper plate is used as a metal core, and an insulating layer 21a made of 0.2 mm thick resin (FR-4 (flame resistant glass base epoxy resin laminate)) is formed on both sides. About the processed material 41, the outer shape clearance c was 0.03 mm or more and smaller than 0.08 mm. In particular, an outer shape processing gap c of 0.05 mm was obtained for the following reason.

  That is, the appropriate gap determined based on the material and thickness of the metal core 11 is 0.08 mm, and the appropriate gap determined based on the material and thickness of the insulating layer 21a is 0.01 mm. Therefore, although the intermediate value of these is 0.045 mm, the ratio (insulating layer thickness / metal core thickness) between the thicknesses of the insulating layers 21a and 21a on both sides and the thickness of the metal core 11 is 1: 2. That is, two insulating layers 21a and 21a having the same thickness as the metal core 11 are formed. However, as described above, the thickness of each insulating layer 21a is 0.2 mm, which is half of the metal core, and since the hardness of the insulating layer 21a made of epoxy is relatively high, the insulating layer 21a is considered to be relatively thin, The intermediate value of 0.045 mm was corrected upward to 0.05 mm.

  This 0.05 mm is 12.5% for a metal core thickness of 0.4 mm, and 25% for an insulating layer thickness of 0.2 mm. In the case where the materials are the same and the thicknesses are different, the outer shape processing gap c can be obtained from the thicknesses of the respective parts using the above ratio.

  After setting the outer shape machining gap c in this manner, the front and back of the workpiece 41 are confirmed, and then punching with the press die 51 is performed. That is, the surface that does not have the circuit pattern 31b (see FIG. 6) in the vicinity of the inner peripheral side of the virtual shear line 44, which is the position to perform shearing, of the front and back surfaces of the portion of the workpiece 41 with respect to the substrate material 43. Is processed as an abutment surface 43 a that hits the punch 53. The press mold 51 shown in FIG. 5 is an apparatus in which the portion corresponding to the substrate material 43 to be punched is applied to the punch 53, so that the contact surface 43 a is applied to the punch 53. In the apparatus in which the portion corresponding to is applied to the die 55, the contact surface 43a is applied to the die 55 to perform punching.

  “There is no circuit pattern 31b in the vicinity of the inner peripheral side of the virtual shear line 44” means that the portion without the circuit pattern 31b is longer and wider on the inner peripheral side of the virtual shear line 44 as shown in FIG. In the example of FIG. 6, the length of the virtual shear line 44 and the end of the circuit pattern 31 b can be made longer than the case where the back surface (lower surface) is the front surface (upper surface) ( L1> L2). For this reason, the outer shape is processed as the contact surface 43 a that contacts the back surface with the punch 53.

  Depending on the shape of the circuit pattern 31b, the surface opposite to the surface having the shortest distance between the virtual shear line 44 and the circuit pattern 31b may be the contact surface 43a, or the virtual shear line 44 and the circuit pattern A surface having a higher ratio of a portion having a long distance to 31b may be used as the contact surface 43a. In other words, even if the burr 11a is formed on the metal core 11, the front and back during the outer shape processing are set so as to reduce the possibility of a short circuit.

  In addition, after setting one of the front and back surfaces of the workpiece 41 to be formed as a contact surface 43a that contacts the die 55 or the punch 53 during the outer shape processing, It is desirable to form the circuit pattern 31b designed so that the circuit pattern 31b does not exist.

  The front and back set as described above are identified by a front and back identifier 45 (see FIG. 2) attached in advance to the workpiece 41 before the outer shape processing.

  The front / back identifier 45 may be configured as shown in FIG. 2 by the presence or arrangement of holes formed in the portion corresponding to the unnecessary portion 42 in the metal core 11 in the drilling step. It may be configured by the presence or shape of a non-application portion where no resist is applied in the process. In addition, various configurations can be appropriately employed as long as the configuration has discriminating power.

  When the front and back surfaces of the workpiece 41 are set in this way and then sheared by the die 55 and the punch 53 of the press die 51, the burr 11a of the metal core 11 is generated on the side of the substrate material 43 that contacts the punch 53 (FIG. 5). Virtual line reference). However, since there is no circuit pattern 31b near the inner peripheral side of the virtual shear line 44 on the surface where the burr 11a is generated, as shown in FIG. 6, in other words, the circuit pattern 31b is kept as far away as possible. Since it takes long, the possibility that a short circuit occurs can be eliminated. Further, since the circuit pattern 31b is not in the vicinity, the possibility of occurrence of a short circuit can be eliminated even if the resist is not properly applied.

  This effect is further enhanced because the outer shape processing gap c is set appropriately to suppress the generation of the burr 11a.

  In this way, since the risk of occurrence of a short circuit can be eliminated, it is possible to provide a product with high quality and stable quality without unexpected occurrence of defective products in the final stage of production. In addition to the burrs 11a, the occurrence of “sag” 11b can be suppressed by the above-described outer shape processing gap c, so that a high-quality product can be stably obtained from this point.

  The above-described configuration is one embodiment of the present invention, and the present invention is not limited to the above-described configuration, and other forms can be adopted.

Sectional drawing which shows before the external shape process in the manufacturing process of a metal core board | substrate. The top view of a metal core. Explanatory drawing of external shape processing. Sectional drawing of a press die. Sectional drawing which shows operation | movement of external shape processing. Sectional drawing of a workpiece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Metal core 21a ... Insulating layer 31b ... Circuit pattern 41 ... Work material 43 ... Substrate material 43a ... Contact surface 44 ... Virtual shear line 45 ... Front / back identifier 53 ... Punch 55 ... Die

Claims (5)

Insulating layers are laminated on both sides of the metal core, and after obtaining workpieces with circuit patterns formed on these insulating layers, the base material that is the product from the workpieces is moved relative to the die and punch. A method of manufacturing a metal core substrate that performs outer shape punching by shearing with,
Of the front and back surfaces of the part corresponding to the substrate material in the work material, the contact surface that hits the die or punch with the surface that does not have the circuit pattern in the vicinity of the inner peripheral side of the virtual shear line that is the position to perform shearing As a manufacturing method of a metal core substrate that performs external processing. Insulating layers are laminated on both sides of the metal core, and after obtaining workpieces with circuit patterns formed on these insulating layers, the base material that is the product from the workpieces is moved relative to the die and punch. A method of manufacturing a metal core substrate that performs outer shape punching by shearing with,
Of the front and back surfaces of the part corresponding to the substrate material in the workpiece, the surface on the opposite side to the surface having the part with the shortest distance between the virtual shear line that is the position to perform shearing and the circuit pattern is die or A method for manufacturing a metal core substrate, in which an outer shape is processed as an abutting surface to be applied to a punch. Insulating layers are laminated on both sides of the metal core, and after obtaining workpieces with circuit patterns formed on these insulating layers, the base material that is the product from the workpieces is moved relative to the die and punch. A method of manufacturing a metal core substrate that performs outer shape punching by shearing with,
Of the front and back surfaces of the part corresponding to the substrate material in the work material, the surface with the higher ratio of the part where the distance between the virtual shear line, which is the shearing position, and the circuit pattern is long is applied to the die or punch. A method of manufacturing a metal core substrate that performs external processing as a contact surface. Insulating layers are laminated on both sides of the metal core, and after obtaining workpieces with circuit patterns formed on these insulating layers, the base material that is the product from the workpieces is moved relative to the die and punch. A method of manufacturing a metal core substrate that performs outer shape punching by shearing with,
The circuit pattern exists in the vicinity of the inner circumference side of the virtual shear line, which is the position to perform shearing, after setting either the front or back surface of the workpiece to the contact surface that contacts the die or punch during external processing Form the above circuit pattern designed not to
A method of manufacturing a metal core substrate in which the contact surface is applied to a die or a punch to perform external processing. The front-and-back identifier which identifies the front and back at the time of the external shape process defined based on the positional relationship of the said circuit pattern and a virtual shear line is previously attached | subjected with respect to the workpiece before an external shape process. The manufacturing method of the metal core board | substrate as described in any one of these.

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