Metal circuit pattern and method for manufacturing the same

Abstract

The present invention provides a metal circuit pattern and a method for manufacturing the metal circuit pattern. A technology capable of efficiently manufacturing a circuit substrate is provided. The metal circuit pattern is a metal circuit pattern for manufacturing a circuit substrate formed by bonding a metal plate forming the circuit pattern to a ceramic substrate, and comprises: a plurality of metal sheets that are each independent and used to form the circuit pattern; and a carrier tape to which the plurality of metal sheets are attached in a state where the circuit pattern is maintained in its original state, and at least any one side of the plurality of metal sheets has a cross section and a shear surface, and also has a friction mark that is different from the shear mark of the shear surface.

Description

Technical Field

[0001] The invention relates to a metal circuit pattern and a method for manufacturing the metal circuit pattern. Background Art

[0002] As a power module substrate, a circuit substrate formed by bonding a metal plate having a circuit pattern to an insulating substrate is widely used. For example, Patent Document 1 proposes a ceramic circuit substrate formed by bonding a copper plate to an alumina plate. In addition, as an insulating substrate, a high heat dissipation resin substrate containing a resin material and a thermally conductive filler is sometimes used.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 3-145748 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] An object of the present invention is to provide a technology capable of efficiently manufacturing a circuit board.

[0008] Solutions for solving problems

[0009] According to one technical solution of the present invention, there is provided a metal circuit pattern, which is a metal circuit pattern for manufacturing a circuit substrate formed by bonding a metal plate forming a circuit pattern to an insulating substrate, wherein:

[0010] The metal circuit pattern has:

[0011] A plurality of metal sheets, each independent of the other, for forming the circuit pattern; and

[0012] a carrier tape to which the plurality of metal sheets are attached while maintaining the circuit pattern,

[0013] At least any one side surface of the plurality of metal sheets has a cross section and a shear surface, and also has a friction mark different from the shear mark of the shear surface.

[0014] According to another technical solution of the present invention, there is provided a method for manufacturing a metal circuit pattern, wherein the method for manufacturing a metal circuit pattern is a method for manufacturing a metal circuit pattern for manufacturing a circuit substrate by bonding a metal plate to a high heat dissipation resin substrate containing a resin material and a thermally conductive filler, wherein:

[0015] The method for manufacturing the metal circuit pattern comprises:

[0016] A stamping process for punching a metal sheet into a plurality of independent metal sheets; and

[0017] A step of attaching the carrier tape to the plurality of metal sheets,

[0018] In the punching process, the plurality of metal sheets punched out at one time are pushed back toward the punching holes of the metal sheet blank, thereby forming friction marks on the side surfaces of the plurality of metal sheets.

[0019] In the pasting step, the plurality of metal pieces are removed from the punched holes of the metal plate blank, and the carrier tape is pasted while the circuit patterns of the plurality of metal pieces are maintained.

[0020] Effects of the Invention

[0021] According to the present invention, a circuit board can be manufactured efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1A It is a plan view of the metal circuit pattern 10 according to the first embodiment of the present invention.

[0023] Figure 1B It is a side view of the metal circuit pattern 10 according to the first embodiment of the present invention.

[0024] Figure 1C It is an enlarged view of the side surface of the metal single piece 12 according to the first embodiment of the present invention.

[0025] Figure 2 This is a flowchart showing an example of a method for manufacturing the metal circuit pattern 10 according to the first embodiment of the present invention.

[0026] Figure 3A It is a schematic cross-sectional view showing a part of the pressing step S2 according to the first embodiment of the present invention.

[0027] Figure 3B It is a schematic cross-sectional view showing a part of the pressing step S2 according to the first embodiment of the present invention.

[0028] Figure 3C It is a schematic cross-sectional view showing a part of the pressing step S2 according to the first embodiment of the present invention.

[0029] Figure 4A It is a schematic cross-sectional view showing a part of the sticking step S3 according to the first embodiment of the present invention.

[0030] Figure 4B It is a schematic cross-sectional view showing a part of the sticking step S3 according to the first embodiment of the present invention.

[0031] Figure 5A It is a plan view of a metal circuit pattern 40 according to a modified example of the first embodiment of the present invention.

[0032] Figure 5B It is a longitudinal sectional view of a metal circuit pattern 40 according to a modified example of the first embodiment of the present invention.

[0033] Fig. 6A It is a plan view of a metal circuit pattern 50 according to a second embodiment of the present invention.

[0034] Figure 6B It is a side view of the metal circuit pattern 50 according to the second embodiment of the present invention.

[0035] Description of Reference Numerals

[0036] 10. Metal circuit pattern; 11. Carrier tape; 12. Metal single piece; 13. Friction mark; 14. Main surface; 15. Main surface; 16. Section; 17. Shear surface; 18. Boundary; 19. Shear mark; 20. Metal sheet; 21. Female mold; 22. Punch; 23. Ejector; 24. Unloader; 25. Forming hole; 26. Punching hole; 30. Rod; 31. First head; 32. Second head; 33. Concave part; 40. Metal circuit pattern; 41. Metal frame; 50. Metal circuit pattern; S1. Roughening process; S2. Stamping process; S3. Pasting process; S4. Inspection and packaging process. DETAILED DESCRIPTION

[0037] [Description of Embodiments of the Invention]

[0038] <Insights Obtained by the Inventor>

[0039] First, the findings obtained by the inventors are described.

[0040] As a metal plate for a circuit substrate, for example, a copper plate is widely used from the viewpoint of heat dissipation and conductivity. In addition, as an insulating substrate for a circuit substrate, a ceramic substrate and a high heat dissipation resin substrate are used. As a method for joining a copper plate to a ceramic substrate, known methods include a direct joining method and an active metal method. The direct joining method is, for example, a method in which a copper plate is placed in contact with and heated on a ceramic substrate to generate a eutectic liquid phase such as Cu-O, and then the eutectic liquid phase is cooled and solidified, thereby directly joining the ceramic substrate and the copper plate. On the other hand, the active metal method is, for example, a method in which a ceramic substrate and a copper plate are joined by means of a solder layer containing an active metal such as Ti.

[0041] Also, as a method for forming a circuit pattern of a circuit substrate, for example, there are known methods of punching out a copper plate by press working to form a circuit pattern, and a method of forming a circuit pattern by etching after bonding the entire surface of a copper plate.

[0042] In recent years, the output of semiconductor devices using circuit boards has been increasing, and circuit boards are required to have higher heat dissipation properties. Therefore, the copper plate used for the circuit board preferably has a thickness of, for example, 0.5 mm or more.

[0043] When the copper plate has a thickness of 0.5 mm or more, it is difficult to form a circuit pattern by etching. On the other hand, when the circuit pattern is formed by stamping in advance, it is difficult to handle the independent metal single piece after punching. Specifically, for example, it is difficult to position the metal circuit pattern when it is bonded to the insulating substrate. In addition, when the circuit pattern is formed by stamping in advance, there is a problem of burrs.

[0044] The inventors of the present application have conducted in-depth research on the above phenomenon. As a result, they have found the following insights: by using the push-back method in the stamping process, the metal single piece is attached to the carrier tape in a state where the circuit pattern is maintained, so that the independent metal single piece can be easily handled and the circuit substrate can be manufactured efficiently. In addition, they have found insights that can suppress the generation of burrs.

[0045] The present invention is based on the above-mentioned findings found by the inventors.

[0046] [Details of Embodiments of the Invention]

[0047] Next, an embodiment of the present invention will be described below with reference to the accompanying drawings. The present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0048] <First embodiment of the present invention>

[0049] (1) Structure of Metal Circuit Pattern

[0050] The metal circuit pattern 10 of the present embodiment is a part of a component of a circuit substrate for a power module or the like. By joining the metal circuit pattern 10 of the present embodiment to an insulating substrate, a circuit substrate can be manufactured. As an insulating substrate, a ceramic substrate formed of, for example, aluminum oxide or aluminum nitride, or a high heat dissipation resin substrate containing a resin material and a thermally conductive filler can be used. In addition, in this specification, a high heat dissipation resin substrate refers not only to a rigid (hard) substrate, but also includes a flexible substrate, a substrate commonly referred to as a heat dissipation insulating sheet, a heat dissipation grease, a heat dissipation tape, and a heat dissipation adhesive. Below, the structure of the metal circuit pattern 10 of the present embodiment is described.

[0051] Figure 1A It is a top view of the metal circuit pattern 10 according to the present embodiment. Figure 1BIt is a side view of the metal circuit pattern 10 of this embodiment. Figure 1C is an enlarged view of the side of the metal single piece 12. Figure 1A and Figure 1B As shown, the metal circuit pattern 10 of this embodiment includes a carrier tape 11 and a plurality of metal sheets 12 .

[0052] The carrier tape 11 is configured to attach a plurality of metal sheets 12 with the circuit patterns intact. For example, a tape obtained by applying a synthetic resin adhesive to a plastic film such as PET (polyethylene terephthalate), polyester, or polypropylene can be used as the carrier tape 11.

[0053] A plurality of metal sheets 12 are respectively and independently attached to the carrier tape 11 to form a circuit pattern. Examples of the material of the plurality of metal sheets 12 include copper or copper alloy. The thickness of the plurality of metal sheets 12 is preferably, for example, greater than 0.5 mm and less than 4.0 mm. In the case where the thickness of the plurality of metal sheets 12 is less than 0.5 mm, there is a possibility that sufficient heat dissipation equivalent to that required for the substrate for the power module cannot be obtained. In contrast, by setting the thickness of the plurality of metal sheets 12 to greater than 0.5 mm, sufficient heat dissipation equivalent to that required for the substrate for the power module can be obtained. On the other hand, if the thickness of the plurality of metal sheets 12 exceeds 4.0 mm, the productivity is poor. In contrast, by setting the thickness of the plurality of metal sheets 12 to less than 4.0 mm, the productivity can be improved. In addition, if the balance between heat dissipation and productivity is considered, the thickness of the plurality of metal sheets 12 is more preferably greater than 0.7 mm and less than 3.0 mm.

[0054] Since the circuit pattern is held by the carrier tape 11, the metal circuit pattern 10 of this embodiment can easily handle a plurality of metal pieces 12. Specifically, for example, the metal circuit pattern 10 can be easily positioned when being bonded to an insulating substrate. Thus, the circuit substrate can be efficiently manufactured.

[0055] In addition, if Figure 1B As shown, the side surfaces of the plurality of metal sheets 12 have friction marks 13. In this specification, "friction marks" refer to marks formed by, for example, metals rubbing against each other. The friction marks 13 extend, for example, along the thickness direction of the plurality of metal sheets 12 and are interrupted at predetermined positions. In addition, it is not necessarily necessary for all the side surfaces of the plurality of metal sheets 12 to have friction marks 13, and there may also be side surfaces without friction marks 13. At least any one side surface of the plurality of metal sheets 12 has friction marks 13, and among the plurality of metal sheets 12 possessed by the metal circuit pattern 10, preferably more than 50% of the metal sheets 12 have friction marks 13 on their side surfaces, more preferably more than 70% of the metal sheets 12 have friction marks 13 on their side surfaces, and further preferably more than 90% of the metal sheets 12 have friction marks 13 on their side surfaces.

[0056] Here, for a conventional power module, a semiconductor element is soldered to a circuit substrate, a metal circuit pattern and the semiconductor element are connected to an external terminal with a welding wire, and then, in order to ensure insulation, it is sealed with a resin such as silicone (hereinafter referred to as a sealing resin). Such a power module is also called a package module. In the case where the metal circuit pattern 10 of the present embodiment is used in such a package module as described above, since the side surfaces of the plurality of metal sheets 12 have friction marks 13, the closeness between the circuit substrate and the sealing resin can be improved. Thus, for example, when vibration is applied to the package module, the vibration of the circuit substrate can be suppressed. As a result, the breakage of the welding wire can be suppressed, and the reliability of the semiconductor device can be improved.

[0057] Furthermore, when the metal circuit pattern 10 of the present embodiment is used in the above-mentioned package module, the side surfaces of the plurality of metal pieces 12 have the friction marks 13, so the solder wettability of the side surfaces of the plurality of metal pieces 12 is reduced. Thus, for example, when a semiconductor element is soldered to a circuit board, the risk of excess solder overflowing and flowing out can be reduced.

[0058] The metal circuit pattern 10 of this embodiment is as follows Figure 1B As shown, the main surface 14 of the plurality of metal sheets 12 close to the friction mark 13 is attached to the carrier tape 11. On the other hand, the main surface 15 of the plurality of metal sheets 12 away from the friction mark 13 is exposed. Figure 1C As shown in FIG. 1 , the peripheral edge of the main surface 15 on the side away from the friction mark 13 is a so-called rounded surface having a smooth R shape. The maximum height Rz2 of the peripheral edge of the main surface 15 on the side away from the friction mark 13 is smaller than the maximum height Rz1 of the peripheral edge of the main surface 14 on the side close to the friction mark 13. In addition, the maximum height Rz is specified by Japanese Industrial Standard JIS B0601-2001. In addition, in this specification, the rounded corner refers to the smooth R shape generated on the cross section of the flat plate when the flat plate is sheared. In addition, the main surface on the side where the rounded corner is generated is called a rounded corner surface.

[0059] like Figure 1CAs shown, the side surfaces of the plurality of metal sheets 12 have cross sections 16 and shear surfaces 17. The cross section 16 is a surface with severe unevenness located on the side of the main surface 14, and the shear surface 17 is a smooth surface located on the side of the main surface 15. In addition, it is not necessary that all the side surfaces of the plurality of metal sheets 12 have cross sections 16 and shear surfaces 17, and there may be side surfaces without cross sections 16 and shear surfaces 17. At least any one side surface of the plurality of metal sheets 12 has cross sections 16 and shear surfaces 17, and preferably more than 50% of the side surfaces of the plurality of metal sheets 12 included in the metal circuit pattern 10 have cross sections 16 and shear surfaces 17, more preferably more than 70% of the side surfaces of the metal sheets 12 have cross sections 16 and shear surfaces 17, and further preferably more than 90% of the side surfaces of the metal sheets 12 have cross sections 16 and shear surfaces 17.

[0060] like Figure 1C As shown in the figure, there is a case where a scratch (hereinafter referred to as a shear scratch 19) caused by shearing is formed in the thickness direction of the metal single piece 12 on the shear surface 17, but the friction scratch 13 of the metal circuit pattern 10 of the present embodiment is different from such a shear scratch 19. That is, the side surfaces of the plurality of metal single pieces 12 have a friction scratch 13 that is different from the shear scratch 19 of the shear surface 17. Specifically, for example, the length of the friction scratch 13 is shorter than the length of the shear scratch 19. The shear scratch 19 has a length that is substantially the same as the thickness of the shear surface 17, whereas the length of the friction scratch 13 is shorter than the thickness of the shear surface 17. It is preferred that the length of the friction scratch 13 is shorter than half the thickness of the shear surface 17. Thus, it is easy to suppress the generation of burrs when manufacturing the metal circuit pattern 10.

[0061] In the metal circuit pattern 10 of the present embodiment, the friction mark 13 is preferably formed near the boundary 18 between the cross section 16 and the shear surface 17, and more preferably formed on the shear surface 17 side from the boundary 18. On the side surfaces of the plurality of metal monoliths 12, the surface roughness decreases sharply from the cross section 16 to the shear surface 17, and therefore, the vicinity of the boundary 18 is a location where the adhesion between the circuit substrate and the sealing resin is easily reduced. By forming the friction mark 13 at such a location, the reduction in the surface roughness of the side surfaces of the plurality of metal monoliths 12 can be suppressed, and the adhesion between the circuit substrate and the sealing resin can be improved.

[0062] When the metal circuit pattern 10 of the present embodiment is bonded to an insulating substrate, the main surface 15 on the side away from the friction mark 13 is bonded to the insulating substrate, so that the bonding can be performed while the circuit pattern is maintained in its original state. That is, by bonding the main surface 15 on the side not attached to the carrier tape 11 to the insulating substrate, the carrier tape 11 can be used to bond while the circuit pattern is maintained in its original state. In this case, since the main surface 15 on the side away from the friction mark 13 is a rounded surface, the contact surface between the main surface 15 and the insulating substrate is flat. That is, the peripheral portion of the main surface 15 on the side away from the friction mark 13 does not have protrusions that hinder contact with the insulating substrate, so the contact surface with the insulating substrate can be made flat. As a result, for example, when the metal circuit pattern 10 is bonded to a ceramic substrate, the bonding between the metal circuit pattern 10 and the ceramic substrate can be improved.

[0063] In addition, as described above, when the main surface 15 on the side away from the friction mark 13 is bonded to the ceramic substrate, the semiconductor element is soldered on the main surface 14 on the side close to the friction mark 13. In this case, the friction mark 13 exists at a position close to the surface to be soldered, so the risk of excess solder overflowing and flowing out can be reduced.

[0064] When the metal circuit pattern 10 of the present embodiment is bonded to a high heat dissipation resin substrate, it is preferred that at least one main surface (preferably the main surface on the side not attached to the carrier tape 11, in the present embodiment, the main surface 15) of the plurality of metal sheets 12 be a roughened surface. In this case, by bonding the roughened surface to the high heat dissipation resin substrate, the bonding between the metal circuit pattern 10 and the high heat dissipation resin substrate can be improved. In addition, it is preferred that the arithmetic mean roughness Ra (Japanese Industrial Standard JIS B0601-2001) of the roughened surface is 0.15 μm or more and 5 μm or less.

[0065] (2) Method for manufacturing metal circuit pattern

[0066] Next, a method for manufacturing the metal circuit pattern 10 according to the present embodiment will be described.

[0067] Figure 2 1 is a flowchart showing an example of a method for producing the metal circuit pattern 10 of the present embodiment. The method for producing the metal circuit pattern 10 of the present embodiment includes, for example, a roughening step S1, a punching step S2, a pasting step S3, and an inspection and packaging step S4.

[0068] (Roughening process S1)

[0069] In the roughening process step S1, at least one main surface of the metal plate blank 20 is roughened. For the metal plate blank 20, a metal material having a predetermined thermal conductivity and a predetermined electrical conductivity corresponding to the characteristics of the semiconductor element to be mounted on the circuit board, such as copper or a copper alloy, can be used. In addition, in order to make the metal circuit pattern 10 have predetermined strength, heat resistance and other characteristics, a predetermined amount of additional elements such as iron, zinc, phosphorus, tin, nickel, etc. can also be added to the above-mentioned metal material.

[0070] In the roughening process step S1, for example, a sulfuric acid-based etching solution is used to roughen at least one main surface of the metal sheet blank 20 to form a roughened surface. In the roughening process step S1, the roughening process is preferably performed so that the arithmetic mean roughness Ra of the roughened surface becomes 0.15 μm or more and 5 μm or less. Thus, by bonding the roughened surface to the high heat dissipation resin substrate, the bonding between the metal circuit pattern 10 and the high heat dissipation resin substrate can be improved. In addition, the roughening process step S1 can also be omitted.

[0071] (Pressing process S2)

[0072] In the punching step S2 , the metal plate blank 20 is punched out to form a plurality of independent metal pieces 12 for forming a circuit pattern.

[0073] Figure 3A , Figure 3B as well as Figure 3C FIG. 2 is a schematic cross-sectional view showing a portion of the stamping process S2. In the stamping process S2, first, the metal sheet blank 20 is fed into the press. Figure 3A As shown, for example, a die 21, a punch 22, an ejector 23 and a stripper 24 are provided in the press.

[0074] The female die 21 has a forming hole 25 for forming the metal sheet blank 20 into a predetermined circuit pattern shape. And, after the metal sheet blank 20 is fed between the female die 21 and the punch 22, as shown in FIG. Figure 3B As shown, the punch 22 is lowered to press down the ejector 23 in the forming hole 25, and a plurality of metal pieces 12 are punched out from the metal sheet blank 20 into the forming hole 25. At this time, the discharger 24 plays the role of a pressing plate to suppress the metal sheet blank 20. When the metal piece 12 is punched out, a section 16 and a shear surface 17 are formed on the side of the metal piece 12. The section 16 is formed on the punch 22 side, and the shear surface 17 is formed on the ejector 23 side.

[0075] After punching out a plurality of metal sheets 12 from the metal sheet blank 20, Figure 3CAs shown, the ejector 23 is raised to push the punch 22 upward, and the plurality of metal sheets 12 punched out at one time are pushed back into the punching holes 26 of the original metal sheet blank 20. Such a forming method is also called a push-back method. By adopting the push-back method, the generation of burrs can be suppressed. In addition, the next process can be carried out with the circuit pattern intact.

[0076] In addition, when the punched metal pieces 12 are pushed back into the punching holes 26, for example, by appropriately controlling the gap between the female die 21 and the punch 22, the inner peripheral surface of the punching holes 26 of the metal sheet blank 20 and the outer peripheral surface of the punched metal pieces 12 can be rubbed against each other. Thus, friction marks 13 can be formed on the side surfaces of the metal pieces 12. More specifically, friction marks 13 can be formed on the side surfaces of the metal pieces 12 in the region close to the punch 22. The friction marks 13 are formed along the punching direction of the press, that is, along the thickness direction of the metal pieces 12.

[0077] The friction marks 13 are preferably formed to have a length shorter than half the thickness of the shear surface 17. By forming the friction marks 13 in this way, the generation of burrs can be suppressed. In addition, the friction marks 13 are preferably formed near the boundary 18 between the cross section 16 and the shear surface 17 on the side surface of the plurality of metal pieces 12, and more preferably formed on the shear surface 17 side from the boundary 18. Thereby, the adhesion between the circuit board and the sealing resin can be improved.

[0078] In addition, when the punched metal pieces 12 are pushed back into the punching holes 26, for example, a portion of the thickness of the metal pieces 12 is pushed back to fit into the punching holes 26. By pushing back to fit a portion of the thickness of the metal pieces 12 to fit into the punching holes 26, the friction marks 13 are formed to be interrupted at predetermined positions.

[0079] The peripheral edge of the main surface 14 of the plurality of metal single pieces 12 on the side close to the friction mark 13 (the punch 22 side) is an area where burrs are easily generated. On the other hand, the main surface 15 of the plurality of metal single pieces 12 on the side away from the friction mark 13 (the ejector 23 side) is a so-called rounded surface having a smooth R-shaped peripheral edge. In the stamping step S2, the plurality of metal single pieces 12 are formed in such a manner that the maximum height Rz2 of the peripheral edge of the main surface 15 on the side away from the friction mark 13 is smaller than the maximum height Rz1 of the peripheral edge of the main surface 14 on the side close to the friction mark 13.

[0080] Furthermore, when punching out a plurality of metal pieces 12 from the metal sheet blank 20, it is preferred that the descent of the punch 22 be stopped at a stage where the tip of the punch 22 has not yet reached the opening end of the forming hole 25 of the female die 21, and the punch 22 be pushed back in this state. This can suppress the generation of burrs.

[0081] (Pasting process S3)

[0082] In the pasting step S3, the carrier tape 11 is pasted to the plurality of metal pieces 12. First, the plurality of metal pieces 12 are kept fitted in the punched holes 26 of the metal plate blank 20 and are fed into a pasting device with the circuit pattern still thereon.

[0083] Figure 4A and Figure 4B 2 is a schematic cross-sectional view showing a portion of the pasting step S3. Figure 4A and Figure 4B As shown, for example, the sticking device is provided with a rod 30, a first head 31, and a second head 32.

[0084] like Figure 4A As shown, the rod 30 is provided with a recess 33 for holding the plurality of metal sheets 12. The position of the rod 30 is adjusted so that the recess 33 is located below the plurality of metal sheets 12. Then, the first head 31 is lowered to remove the plurality of metal sheets 12 engaged with the punching holes 26. The removed plurality of metal sheets 12 can be moved using the recess 33 of the rod 30 while maintaining the circuit pattern.

[0085] Next, the rod 30 is moved downward from the second head 32, and the carrier tape 11 is fed between the second head 32 and the rod 30. After that, the second head 32 is lowered, the carrier tape 11 is punched into a predetermined size, and is attached to the plurality of metal sheets 12. That is, the carrier tape 11 is attached while the circuit patterns of the plurality of metal sheets 12 are maintained. Thus, the plurality of metal sheets 12 can be easily handled. As a result, the circuit board can be efficiently manufactured.

[0086] In addition, as described above, the peripheral edge of the main surface 14 of the plurality of metal sheets 12 near the friction mark 13 is an area where burrs are easily generated. In the case where burrs are generated on the peripheral edge of the main surface 14 of the plurality of metal sheets 12 near the friction mark 13, the burrs can be compressed and reduced by adjusting the load of the second head 32 when attaching the carrier tape 11.

[0087] In the pasting step S3, the carrier tape 11 is pasted to the main surface 14 of the plurality of metal sheets 12 on the side close to the friction mark 13. Thus, the main surface 15 on the side not pasted to the carrier tape 11 can be joined to the insulating substrate in a state where the circuit pattern is maintained. In addition, in this case, since the main surface 15 on the side away from the friction mark 13 is a rounded surface, the contact surface between the main surface 15 and the insulating substrate is flat. Thus, for example, when the metal circuit pattern 10 is joined to a ceramic substrate, the bonding between the metal circuit pattern 10 and the ceramic substrate can be improved.

[0088] (Inspection and packaging process S4)

[0089] In the inspection and packaging step S4, first, the appearance inspection of the metal circuit pattern 10 to which the carrier tape 11 is attached is performed. In the appearance inspection, for example, it is inspected whether there are scratches, deformations, pits, etc. on the metal circuit pattern 10. Next, the metal circuit pattern 10 is packaged. The metal circuit pattern 10 judged as a qualified product in the appearance inspection is stored in a packaging container, for example, in units of a predetermined number of pieces, so that the metal circuit pattern 10 is packaged.

[0090] The finished metal circuit pattern 10 is manufactured through the above steps.

[0091] In the method for manufacturing the metal circuit pattern 10 of the present embodiment, as described above, the push-back method is adopted in the punching step S2, and the carrier tape 11 is pasted in the pasting step S3 while the circuit patterns of the plurality of metal pieces 12 are maintained, so that the plurality of metal pieces 12 can be easily handled. As a result, the circuit board can be efficiently manufactured.

[0092] In addition, in the method for manufacturing the metal circuit pattern 10 of the present embodiment, as described above, by appropriately controlling the gap between the female mold 21 and the punch 22 in the punching step S2, it is possible to form friction marks 13 on the side surfaces of the plurality of metal pieces 12. This can improve the adhesion between the circuit board and the sealing resin, for example.

[0093] (3) Effects of this embodiment

[0094] According to the present embodiment, one or more of the following effects are achieved.

[0095] (a) The metal circuit pattern 10 of this embodiment can easily handle a plurality of metal pieces 12 because the circuit pattern is held by the carrier tape 11. Specifically, for example, the metal circuit pattern 10 can be easily positioned when bonding an insulating substrate to the metal circuit pattern 10.

[0096] Here, in the conventional circuit substrate, when joining the metal circuit pattern to the insulating substrate, for example, a plate-shaped jig punched into the shape of the circuit pattern needs to be placed on the insulating substrate, and the metal pieces are arranged one by one, so the workability is poor. In addition, there is a possibility that the accuracy of the circuit pattern is reduced due to vibration when the jig is removed or when it is transported to the heating furnace. In addition, when the metal circuit pattern is formed by stamping, there is a problem of burrs.

[0097] In contrast, when the metal circuit pattern 10 of the present embodiment is bonded to the insulating substrate, the metal circuit pattern 10 can be laminated on the insulating substrate in units of the carrier tape 11, so that the operability can be greatly improved compared to the conventional method. In addition, the accuracy of the circuit pattern can be improved. Moreover, since the push-back method is adopted, the generation of burrs can be suppressed. Therefore, the circuit substrate can be manufactured efficiently.

[0098] (b) When the metal circuit pattern 10 of the present embodiment is used in the above-mentioned package module, the side surfaces of the plurality of metal sheets 12 have the friction marks 13, so that the adhesion between the circuit substrate and the sealing resin can be improved. Thus, for example, when the package module is vibrated, the vibration of the circuit substrate can be suppressed. As a result, the breakage of the bonding wire can be suppressed, and the reliability of the semiconductor device can be improved.

[0099] (c) When the metal circuit pattern 10 of the present embodiment is used in the above-mentioned package module, the side surfaces of the plurality of metal sheets 12 have the friction marks 13, so the solder wettability of the side surfaces of the plurality of metal sheets 12 is reduced. Thus, for example, when a semiconductor element is soldered to a circuit board, the risk of excess solder overflowing and flowing out can be reduced.

[0100] (d) In the metal circuit pattern 10 of the present embodiment, the length of the friction mark 13 is preferably shorter than the length of the shearing mark 19 and shorter than half the thickness of the shearing surface 17. This can suppress the generation of burrs.

[0101] (e) In the metal circuit pattern 10 of the present embodiment, the friction mark 13 is preferably formed near the boundary 18 between the cross section 16 and the shear surface 17, and more preferably formed on the shear surface 17 side from the boundary 18. Thus, the change in the surface roughness of the side surfaces of the plurality of metal pieces 12 can be made gentle, and the adhesion between the circuit board and the sealing resin can be improved.

[0102] (f) When the metal circuit pattern 10 of the present embodiment is bonded to an insulating substrate, the main surface 15 on the side away from the friction mark 13 is bonded to the insulating substrate, so that the bonding can be carried out in a state where the circuit pattern is maintained in its original state. That is, by bonding the main surface 15 on the side not attached to the carrier tape 11 to the insulating substrate, the carrier tape 11 can be used to bond the circuit pattern in a state where the circuit pattern is maintained in its original state. In addition, in this case, since the main surface 15 on the side away from the friction mark 13 is a rounded surface, the contact surface between the main surface 15 and the ceramic substrate is flat. Thus, for example, when the metal circuit pattern 10 is bonded to a ceramic substrate, the bonding between the metal circuit pattern 10 and the ceramic substrate can be improved. Therefore, the metal circuit pattern 10 of the present embodiment can be appropriately used in, for example, a ceramic circuit substrate formed by a direct bonding method in which a copper plate is directly bonded to a ceramic substrate.

[0103] (g) When the metal circuit pattern 10 of the present embodiment is bonded to a high heat dissipation resin substrate, it is preferred that at least one main surface (preferably the main surface on the side not attached to the carrier tape 11, in the present embodiment, the main surface 15) of the plurality of metal sheets 12 be a roughened surface. In this case, by bonding the roughened surface to the high heat dissipation resin substrate, the bonding between the metal circuit pattern 10 and the high heat dissipation resin substrate can be improved. Therefore, the metal circuit pattern 10 of the present embodiment can also be appropriately used in a circuit substrate formed by bonding a metal plate to a high heat dissipation resin substrate.

[0104] (h) In the method for manufacturing the metal circuit pattern 10 of the present embodiment, the push-back method is adopted in the punching step S2, and the carrier tape 11 is pasted in the pasting step S3 while the circuit patterns of the plurality of metal pieces 12 are maintained, so that the plurality of metal pieces 12 can be easily handled. As a result, the circuit board can be manufactured efficiently.

[0105] (i) In the method for manufacturing the metal circuit pattern 10 of the present embodiment, by appropriately controlling the gap between the female die 21 and the punch 22 in the punching step S2, the friction marks 13 can be formed on the side surfaces of the plurality of metal pieces 12. This can improve the adhesion between the circuit board and the sealing resin, for example.

[0106] (4) Modification of the First Embodiment

[0107] The above-described embodiment can be modified into the following modified examples as needed. Hereinafter, only elements different from those of the above-described embodiment will be described, and elements substantially the same as those described in the above-described embodiment will be denoted by the same reference numerals and their description will be omitted.

[0108] Figure 5AIt is a top view of the metal circuit pattern 40 according to this modification. Figure 5B 4 is a longitudinal cross-sectional view of the metal circuit pattern 40 of this modification. Figure 5A and Figure 5B As shown, the metal circuit pattern 40 of this modification is different from the metal circuit pattern 10 of the first embodiment in that it has a metal frame 41 .

[0109] The metal frame 41 is provided to protect the circuit pattern, and is, for example, attached to the outer periphery of the carrier tape 11. The metal frame 41 can be removed from the carrier tape 11 at any time before the metal circuit pattern 40 is bonded to the insulating substrate.

[0110] Since the metal circuit pattern 40 of this modification has the metal outer frame 41, it is easy to handle a plurality of metal pieces 12. In addition, for example, the circuit pattern can be protected from vibration during packaging or transportation, and the accuracy of the circuit pattern can be improved.

[0111] <Second embodiment of the present invention>

[0112] Next, a second embodiment of the present invention will be described focusing on differences from the first embodiment.

[0113] Fig. 6A 1 is a plan view of the metal circuit pattern 50 according to the present embodiment. Figure 6B is a side view of the metal circuit pattern 50 of this embodiment. Figure 6B As shown, in the metal circuit pattern 50 of this embodiment, the main surface 15 of the plurality of metal pieces 12 on the side away from the friction mark 13 is attached to the carrier tape 11. That is, the surface attached to the carrier tape 11 is opposite to that of the first embodiment.

[0114] The metal circuit pattern 50 of the present embodiment can be manufactured, for example, by placing the carrier tape 11 on the rod 30 in advance when removing the plurality of metal pieces 12 fitted into the punched holes 26 in the pasting step S3 .

[0115] When the metal circuit pattern 50 of the present embodiment is bonded to an insulating substrate, the main surface 14 on the side close to the friction mark 13 is bonded to the insulating substrate, so that the bonding can be performed while the circuit pattern is maintained. In other words, by bonding the main surface 14 on the side not attached to the carrier tape 11 to the insulating substrate, the carrier tape 11 can be used to bond the circuit pattern while the circuit pattern is maintained. In this case, since the main surface 15 on the side away from the friction mark 13 is a rounded surface, when the semiconductor element is mounted on the main surface 15, the risk of damaging the semiconductor element can be reduced.

[0116] In addition, the peripheral portion of the main surface 14 on the side close to the friction mark 13 is an area where burrs are easily generated. When the metal circuit pattern 50 of this embodiment is used in a ceramic circuit substrate formed by, for example, an active metal method in which a copper plate is bonded to a ceramic substrate via a solder layer, the burrs on the peripheral portion of the main surface 14 are in contact with or close to the solder layer. As a result, the burrs become walls, and the seepage of solder to the circuit pattern surface can be suppressed. Therefore, the metal circuit pattern 50 of this embodiment can be appropriately used in, for example, a ceramic circuit substrate formed by an active metal method.

[0117] In addition, when the metal circuit pattern 50 of this embodiment is bonded to a high heat dissipation resin substrate, the burrs on the peripheral portion of the main surface 14 contact the high heat dissipation resin substrate, bringing about an anchoring effect. As a result, the bonding between the metal circuit pattern 10 and the high heat dissipation resin substrate can be improved. Therefore, the metal circuit pattern 10 of this embodiment can also be appropriately used in a circuit substrate formed by bonding a metal plate to a high heat dissipation resin substrate.

[0118] <Other embodiments of the present invention>

[0119] As mentioned above, although embodiment of this invention is specifically described, this invention is not limited to the said embodiment, Various changes are possible within the range which does not deviate from the summary.

[0120] For example, in the above-mentioned embodiment, the following situation is described: in the stamping process S2, when the multiple metal sheets 12 that have been punched out are pushed back into the punching hole 26, they are pushed back in a manner such that a portion of the thickness of the multiple metal sheets 12 is engaged with the punching hole 26, but they can also be pushed back in a manner such that the entire thickness of the multiple metal sheets 12 is engaged with the punching hole 26.

[0121] For example, in the above-mentioned embodiment, the following situation is described: in the stamping process S2, when a plurality of metal sheets 12 are punched out from the metal sheet blank 20, the descent of the punch 22 is stopped at a stage where the top end of the punch 22 has not reached the opening end of the forming hole 25 of the die 21, and push-back is started in this state, but the push-back may also be started after the plurality of metal sheets 12 are completely punched out.

[0122] <Preferred embodiment of the present invention>

[0123] Hereinafter, preferred aspects of the present invention will be described.

[0124] (Appendix 1)

[0125] According to one aspect of the present invention, there is provided a metal circuit pattern, which is a metal circuit pattern for manufacturing a circuit substrate formed by bonding a metal plate forming a circuit pattern to an insulating substrate, wherein:

[0126] The metal circuit pattern has:

[0127] A plurality of metal sheets, each independent of the other, for forming the circuit pattern; and

[0128] a carrier tape to which the plurality of metal sheets are attached while maintaining the circuit pattern,

[0129] At least any one side surface of the plurality of metal sheets has a cross section and a shear surface, and also has a friction mark different from the shear mark of the shear surface.

[0130] (Appendix 2)

[0131] The metal circuit pattern according to Appendix 1, wherein:

[0132] The length of the friction mark is shorter than the length of the shear mark.

[0133] Preferably, the length of the friction mark is shorter than half the thickness of the shear surface.

[0134] (Appendix 3)

[0135] The metal circuit pattern according to Appendix 1 or Appendix 2, wherein:

[0136] The friction marks are formed near the boundaries between the cross sections and the shear surfaces of the plurality of metal sheets.

[0137] Preferably, the friction mark is formed on the shear surface side from the boundary.

[0138] (Appendix 4)

[0139] The metal circuit pattern according to any one of Appendix 1 to Appendix 3, wherein:

[0140] The insulating substrate is a high heat dissipation resin substrate containing a resin material and a thermally conductive filler.

[0141] (Appendix 5)

[0142] The metal circuit pattern according to Appendix 4, wherein:

[0143] At least one main surface of the plurality of metal sheets is a roughened surface.

[0144] Preferably, the main surfaces of the plurality of metal sheets that are not attached to the carrier tape are roughened surfaces.

[0145] Preferably, the arithmetic mean roughness Ra of the roughened surface is 0.15 μm or more and 5 μm or less.

[0146] (Appendix 6)

[0147] The metal circuit pattern according to any one of Appendix 1 to Appendix 5, wherein:

[0148] The main surfaces of the plurality of metal sheets on the side close to the friction mark are adhered to the carrier tape.

[0149] (Appendix 7)

[0150] The metal circuit pattern according to any one of Appendix 1 to Appendix 5, wherein:

[0151] The main surfaces of the plurality of metal sheets on the side away from the friction mark are adhered to the carrier tape.

[0152] (Appendix 8)

[0153] The metal circuit pattern according to any one of Appendix 1 to Appendix 7, wherein:

[0154] The friction marks extend along a thickness direction of the plurality of metal sheets.

[0155] (Appendix 9)

[0156] The metal circuit pattern according to any one of Appendix 1 to Appendix 8, wherein:

[0157] The friction mark is interrupted at a predetermined position.

[0158] (Appendix 10)

[0159] The metal circuit pattern according to any one of Appendix 1 to Appendix 9, wherein:

[0160] The plurality of metal single pieces are formed of copper or a copper alloy and have a thickness of 0.5 mm or more and 4.0 mm or less.

[0161] Preferably, the thickness of the plurality of metal sheets is greater than or equal to 0.7 mm and less than or equal to 3.0 mm.

[0162] (Appendix 11)

[0163] The metal circuit pattern according to any one of Appendix 1 to Appendix 10, wherein:

[0164] The metal circuit pattern further includes a metal outer frame adhered to the outer periphery of the carrier tape.

[0165] (Appendix 12)

[0166] According to another aspect of the present invention, there is provided a method for manufacturing a metal circuit pattern, wherein the method is a method for manufacturing a metal circuit pattern for manufacturing a circuit substrate by bonding a metal plate to a high heat dissipation resin substrate containing a resin material and a thermally conductive filler, wherein:

[0167] The method for manufacturing the metal circuit pattern comprises:

[0168] A stamping process for punching a metal sheet into a plurality of independent metal sheets; and

[0169] A step of attaching the carrier tape to the plurality of metal sheets,

[0170] In the punching process, the plurality of metal sheets punched out at one time are pushed back toward the punching holes of the metal sheet blank, thereby forming friction marks on the side surfaces of the plurality of metal sheets.

[0171] In the pasting step, the plurality of metal pieces are removed from the punched holes of the metal plate blank, and the carrier tape is pasted while the circuit patterns of the plurality of metal pieces are maintained.

[0172] (Appendix 13)

[0173] The method for manufacturing a metal circuit pattern according to Appendix 12, wherein:

[0174] The method for manufacturing a metal circuit pattern further includes a roughening step of roughening at least one main surface of the metal plate blank.

Claims

1. A metal circuit pattern, which is a metal circuit pattern for manufacturing a circuit substrate formed by bonding a metal plate forming a circuit pattern to an insulating substrate, wherein: The metal circuit pattern has: A plurality of metal sheets, each independent of the other, used to form the circuit pattern; as well as a carrier tape to which the plurality of metal sheets are attached while maintaining the circuit pattern, At least one side surface of the plurality of metal sheets has a cross section and a shear surface, and also has a friction mark different from the shear mark of the shear surface. The friction mark is formed on the shear surface side from the boundary between the cross section and the shear surface.

2. The metal circuit pattern according to claim 1, wherein: The length of the friction mark is shorter than the length of the shear mark.

3. The metal circuit pattern according to claim 1 or 2, wherein: The friction mark is formed near the boundary between the cross section and the shear surface.

4. The metal circuit pattern according to claim 1, wherein: The insulating substrate is a high heat dissipation resin substrate containing a resin material and a thermally conductive filler.

5. The metal circuit pattern according to claim 4, wherein: At least one main surface of the plurality of metal sheets is a roughened surface.

6. The metal circuit pattern according to claim 1, wherein: The main surfaces of the plurality of metal sheets on the side close to the friction mark are adhered to the carrier tape.

7. The metal circuit pattern according to claim 1, wherein: The main surfaces of the plurality of metal sheets on the side away from the friction mark are adhered to the carrier tape.

8. A method for producing a metal circuit pattern, which is a method for producing a metal circuit pattern for a circuit substrate, wherein a metal plate is bonded to a high heat dissipation resin substrate containing a resin material and a thermally conductive filler, wherein: The method for manufacturing the metal circuit pattern comprises: A stamping process for punching a metal sheet into a plurality of independent metal sheets; and A step of attaching the carrier tape to the plurality of metal sheets, In the punching process, the plurality of metal pieces punched out at one time are pushed back toward the punching holes of the metal sheet blank, thereby forming friction marks on the shearing surface side from the boundary between the cross section existing on the side surface of the plurality of metal pieces and the shearing surface, In the pasting step, the plurality of metal pieces are removed from the punched holes of the metal plate blank, and the carrier tape is pasted while the circuit patterns of the plurality of metal pieces are maintained.

9. The method for manufacturing a metal circuit pattern according to claim 8, wherein: The method for manufacturing a metal circuit pattern further includes a roughening step of roughening at least one main surface of the metal plate blank.

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