Metal plate material, laminate, insulated circuit board, and method for manufacturing metal plate material

Abstract

This metal sheet material comprises copper or a copper alloy, and has a main sheet body and a roughening plating layer that is formed on the outermost layer of the main sheet body. Engagement protrusions are formed in the roughening plating layer, said engagement protrusions protruding toward the opposite side from the main sheet body, and comprising widening sections that gradually widen in width toward a tip end side in the protrusion direction. In a cross-section along the thickness direction of the main sheet body, a plurality of said engagement protrusions are formed on a surface layer crystal grain that is located on the outermost surface of the main sheet body. When the protrusion height of the engagement protrusions is H (unit: μm), the maximum width of the surface layer crystal grain is W (unit: μm), and the number of protrusions at the maximum width of the surface layer crystal grain is N, N×H / W is 0.5 or greater.

Description

[Technical field]

[0001] The present invention relates to a metal plate, a laminate having a structure in which a resin member and a metal plate are laminated, an insulating circuit board, and a method for manufacturing a metal plate. This application claims priority based on Japanese Patent Application No. 2021-053445, filed on March 26, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] In power modules, LED modules, and thermoelectric modules, power semiconductor elements, LED elements, and thermoelectric elements are bonded to an insulating circuit board having a circuit layer made of a conductive material formed on one side of an insulating layer. As the insulating layer, those using ceramics or insulating resin have been proposed. Here, as an insulating circuit board having an insulating resin layer, for example, Patent Document 1 proposes a metal base circuit board, and Patent Document 2 proposes a multilayer wiring board.

[0003] In the metal base circuit board described in Patent Document 1, an insulating resin layer is formed on a metal substrate, and a circuit layer having a circuit pattern is formed on the insulating resin layer. Here, the insulating resin layer is made of epoxy resin, which is a thermosetting resin, and the circuit layer is made of copper foil. In this metal-based circuit board, a semiconductor element is bonded onto the circuit layer, and a heat sink is disposed on the side of the metal board opposite the insulating resin layer, so that heat generated by the semiconductor element is transferred to the heat sink side and dissipated.

[0004] Moreover, in the multilayer wiring board described in Patent Document 2, the metal foil adhered to the resin film is etched to make the surface roughness (Ra) of the metal foil 0.2 μm or more, and then further etched into a circuit pattern to form a wiring circuit layer. The wiring circuit layer formed on the surface of the resin film is embedded in the surface of a soft insulating sheet while applying pressure to transfer the wiring circuit layer to the surface of the insulating sheet, and multiple insulating sheets thus obtained are stacked and heat-cured together to produce the board. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-207666 A [Patent Document 2] JP 2000-077850 A Summary of the Invention [Problem to be solved by the invention]

[0006] In an insulating circuit board having a structure in which a circuit layer is formed by bonding a metal plate or the like to an insulating resin layer, it is necessary to ensure adhesion between the insulating resin layer and the circuit layer (metal plate) so that peeling does not occur between the insulating resin layer and the circuit layer (metal plate) during use. Here, in the metal base circuit board described in Patent Document 1, no consideration was given to improving the adhesion between the insulating resin layer and the circuit layer, and there was a risk of peeling between the insulating resin layer and the circuit layer (metal plate) during use.

[0007] On the other hand, in the multilayer wiring board described in Patent Document 2, the surface roughness (Ra) of the wiring circuit layer is set to 0.2 μm or more and the wiring circuit layer is embedded in the insulating sheet, thereby improving the adhesion between the insulating sheet and the wiring circuit layer. Here, when the circuit layer is made of pure copper such as oxygen-free copper, which has excellent thermal and electrical conductivity, the crystal grains tend to become coarse. Also, when the circuit layer is formed thick, the crystal grains tend to become coarse. When the crystal grains of the metal plate constituting the circuit layer are coarse, fine irregularities are not formed even after etching, and even if the surface roughness (Ra) is made 0.2 μm or more, there is a risk that adhesion to the insulating sheet cannot be ensured.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a metal plate material having excellent adhesion to a laminated resin member, a laminate in which this metal plate material and a resin member are laminated, an insulated circuit board, and a method for manufacturing the metal plate material. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the metal sheet material of the present invention has a sheet body and a roughened plating layer formed on the outermost layer of the sheet body, and the roughened plating layer is formed with engaging protrusions that protrude toward the opposite side to the sheet body and have a widening portion whose width gradually increases toward the tip side in the protruding direction, and in a cross section along the thickness direction of the sheet body, a plurality of the engaging protrusions are formed on surface crystal grains located on the outermost surface of the sheet body, and N×H / W is 0.5 or more, where H (unit: μm) is the protruding height of the engaging protrusions, W (unit: μm) is the maximum width of the surface crystal grains, and N is the number of the engaging protrusions at the maximum width of the surface crystal grains.

[0010] With this metal plate material having such a configuration, the roughened plating layer formed on the outermost surface has an engaging protrusion that protrudes toward the side opposite the plate body and has a widening portion that gradually becomes wider toward the tip side in the protruding direction. Therefore, when a resin member is laminated on the plate surface of this metal plate material, the engaging protrusion engages with the resin member, making it possible to improve adhesion with the laminated resin member. Furthermore, when the protruding height of the engaging protrusion is H (unit: μm), the maximum width of the surface crystal grain is W (unit: μm), and N is the number of the engaging protrusions at the maximum width of the surface crystal grain, N×H / W is 0.5 or more. Therefore, even if the crystal grains of the plate body are coarse, the engaging protrusions can be sufficiently formed, and adhesion with the laminated resin member can be improved.

[0011] In the metal sheet material of the present invention, the surface layer crystal grains may have a maximum width of 3 μm or more. In this case, even if the maximum width of the surface crystal grains of the plate body is coarsened to 3 μm or more, they can sufficiently engage with the laminated resin material, thereby making it possible to improve adhesion with the resin material.

[0012] In the metal plate material of the present invention, it is preferable that the engaging protrusions have a protruding height of 0.1 μm or more. In this case, since the protruding height of the engaging convex portion is set to 0.1 μm or more, it is possible to reliably improve the adhesion with the laminated resin member.

[0013] Furthermore, in the metal sheet material of the present invention, the sheet body is preferably made of copper or a copper alloy. In this case, since the plate body is made of copper or a copper alloy, it has excellent electrical and thermal conductivity. In addition, even if the crystal grain size of the plate body becomes coarse, it can sufficiently engage with the laminated resin member, and it is possible to improve the adhesion with the resin member.

[0014] The laminate of the present invention is a laminate in which a resin member is laminated on the plate surface of the above-mentioned metal plate material, and is characterized in that at the joint interface between the resin member and the metal plate material, the resin member engages with the engaging protrusion of the metal plate material.

[0015] With this configuration of laminate, a resin member is laminated on the plate surface of a metal plate on which an engaging protrusion having a widening portion whose width gradually increases toward the tip side in the protruding direction is formed, and at the joint interface between the resin member and the metal plate, the resin member engages with the engaging protrusion of the metal plate, making it possible to improve adhesion between the resin member and the metal plate.

[0016] The insulated circuit board of the present invention is an insulated circuit board comprising an insulating resin layer and a circuit layer formed on one side of the insulating resin layer, wherein the circuit layer is formed by bonding the above-mentioned metal plate material to one side of the insulating resin layer, and the insulating resin layer engages with the engaging protrusion of the metal plate material at the bonding interface between the insulating resin layer and the circuit layer.

[0017] In an insulating circuit board of this configuration, a circuit layer is formed by bonding a metal plate material having an engaging protrusion with a widening portion that gradually becomes wider toward the tip side in the protruding direction to one side of an insulating resin layer, and at the bonding interface between the insulating resin layer and the circuit layer, the insulating resin layer engages with the engaging protrusion of the circuit layer (copper member), thereby improving adhesion between the circuit layer and the insulating resin layer.

[0018] The manufacturing method of the metal sheet material of the present invention is a manufacturing method of the metal sheet material for manufacturing the above-mentioned metal sheet material, and is characterized in that the roughened plating layer is formed on the outermost layer of the sheet body by performing DC electrolytic plating on the sheet body and then performing PR pulse electrolytic plating.

[0019] According to this manufacturing method for metal plate material, first, DC electrolytic plating is performed on the plate body, and then PR pulse electrolytic plating is performed. Therefore, even if the surface crystal grains of the plate body are large, multiple fine engaging protrusions can be formed in a dispersed manner on the surface of the large surface crystal grains. Effect of the Invention

[0020] According to the present invention, it is possible to provide a metal plate material having excellent adhesion to a laminated resin member, a laminate in which this metal plate material and a resin member are laminated, an insulated circuit board, and a method for manufacturing the metal plate material. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic explanatory diagram of a power module including an insulating circuit board according to an embodiment of the present invention. [Diagram 2] 1A and 1B are explanatory views of a metal plate according to an embodiment of the present invention, in which (a) is an observation photograph of the vicinity of the surface, and (b) is a schematic diagram of an engaging protrusion. [Diagram 3] 4 is an observation photograph of a bonding interface between a circuit layer and an insulating resin layer of the insulating circuit board according to the embodiment of the present invention. [Figure 4] FIG. 2 is a flow diagram showing a method for manufacturing an insulating circuit board according to an embodiment of the present invention. [Diagram 5] 5 is a schematic explanatory diagram of a method for producing the insulating circuit board shown in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a metal plate, a laminate, and an insulating circuit board according to embodiments of the present invention will be described with reference to the accompanying drawings. The laminate of this embodiment is an insulating circuit board 10 formed by joining an insulating resin layer 12, which is a resin member, to a metal plate material 30 (circuit layer 13) and a metal substrate 11 of this embodiment. FIG. 1 shows an insulating circuit board 10 according to an embodiment of the present invention and a power module 1 using this insulating circuit board 10.

[0023] The power module 1 shown in FIG. 1 includes an insulating circuit board 10, a semiconductor element 3 joined to one surface (the upper surface in FIG. 1) of the insulating circuit board 10 via a first solder layer 2, and a heat sink 41 joined to the other side (the lower surface in FIG. 1) of the insulating circuit board 10 via a second solder layer 42.

[0024] The semiconductor element 3 is made of a semiconductor material such as Si. The first solder layer 2 that joins the insulating circuit board 10 and the semiconductor element 3 is made of, for example, a Sn-Ag based, Sn-Cu based, Sn-In based, or Sn-Ag-Cu based solder material (so-called lead-free solder material).

[0025] The heat sink 41 is for dissipating heat on the insulating circuit board 10 side. The heat sink 41 is made of copper or a copper alloy, aluminum or an aluminum alloy, or the like, which has good thermal conductivity. In this embodiment, the heat sink 41 is a heat sink made of oxygen-free copper. The thickness of the heat sink 41 is set within a range of 3 mm to 10 mm. Here, the insulating circuit board 10 and the heat sink 41 are joined via a second solder layer 42. This second solder layer 42 can have the same configuration as the first solder layer 2 described above.

[0026] As shown in FIG. 1, the insulating circuit board 10 of this embodiment comprises a metal substrate 11, an insulating resin layer 12 formed on one surface (the upper surface in FIG. 1) of the metal substrate 11, and a circuit layer 13 formed on one surface (the upper surface in FIG. 1) of the insulating resin layer 12.

[0027] Metal substrate 11 has the effect of improving heat dissipation characteristics by spreading heat generated in semiconductor element 3 mounted on insulating circuit substrate 10 in the planar direction. For this reason, metal substrate 11 is made of a metal with excellent thermal conductivity, such as copper or a copper alloy, aluminum or an aluminum alloy. In this embodiment, it is made of a rolled sheet of oxygen-free copper. The thickness of metal substrate 11 is set within the range of 0.05 mm to 3 mm, and in this embodiment, it is set to 2.0 mm.

[0028] The insulating resin layer 12 prevents electrical connection between the circuit layer 13 and the metal substrate 11, and is made of an insulating thermosetting resin. In this embodiment, in order to ensure the strength of the insulating resin layer 12 and to ensure thermal conductivity, a thermosetting resin containing a filler may be used. Here, for example, alumina, boron nitride, aluminum nitride, etc. can be used as the filler. Also, epoxy resin, polyimide resin, etc. can be used as the thermosetting resin. In this embodiment shown in FIG. 3, the insulating resin layer 12 is made of an epoxy resin that does not use a filler. In other embodiments, it is made of an epoxy resin that contains boron nitride as a filler. Also, the thickness of the insulating resin layer 12 is set to a range of 20 μm to 250 μm, and is set to 150 μm in this embodiment.

[0029] As shown in FIG. 5(a), the circuit layer 13 is formed by joining a metal plate material 30 (circuit layer 13) of this embodiment to one surface (the upper surface in FIG. 5(a)) of the insulating resin layer 12. A circuit pattern is formed on this circuit layer 13, and one surface thereof (the upper surface in FIG. 1) serves as a mounting surface on which a semiconductor element 3 is mounted. Here, the thickness of the circuit layer 13 is set within a range of 0.3 mm to 3 mm, and is set to 0.5 mm in this embodiment.

[0030] Here, the metal plate 30 according to this embodiment on which the above-mentioned circuit layer 13 is formed will be described with reference to Figs. 2(a) and 2(b). The metal plate material 30 in this embodiment is made of a metal having excellent electrical conductivity and thermal conductivity, and in this embodiment, is made of copper or a copper alloy, and specifically, is made of oxygen-free copper. As shown in FIG. 2(a), the metal plate 30 according to this embodiment includes a plate body 31 and a roughened plating layer 35 formed on the outermost surface of the plate body 31.

[0031] As shown in FIG. 2(a), this roughened plating layer 35 has an engaging protrusion 36 formed therein, which protrudes toward the opposite side to the plate body 31 (the upper side in FIG. 2(a)) and has a widening portion 36a whose width gradually increases toward the tip side in the protruding direction. The roughened plating layer 35 may be made of a different material from that of the metal sheet material 30, and is preferably made of a material having better thermal conductivity than the insulating resin layer 12. In this embodiment, the roughened plating layer 35 is made of copper or a copper alloy having the same composition as that of the metal sheet material 30. Here, in a cross section along the thickness direction of the plate body 31, as shown in Figure 2(a), a plurality of engaging protrusions 36 are formed on the surface crystal grains 32 located on the outermost surface of the plate surface, and when the protruding height of the engaging protrusions 36 is H (unit: μm), the maximum width of the surface crystal grains 32 is W (unit: μm), and the number of engaging protrusions 36 at the maximum width W of the surface crystal grains 32 is N, N × H / W is 0.5 or more. The maximum width W of the surface crystal grain 32 is measured at the interface between the sheet body 31 and the roughened plating layer 35, as shown in FIG. 2(a).

[0032] In the metal sheet 30 according to the present embodiment, the maximum width W of the surface crystal grains 32 located on the outermost surface of the sheet may be 3 μm or more. There is no particular upper limit to the maximum width W, but it is generally 200 μm or less, and is at most 1000 μm. The maximum width W of the surface crystal grains 32 located on the outermost surface of the sheet surface can be determined by observing a cross section along the thickness direction of the sheet body 31 using a scanning electron microscope (SEM) and measuring the width of the crystal grains in contact with the roughened plating layer 35 in a direction perpendicular to the thickness direction, as shown in FIG. 2(a). That is, the interface between the plate body 31 and the roughened plating layer 35, observed at a cross section along the thickness direction of the plate body 31 and the roughened plating layer 35, was observed with a scanning electron microscope (SEM) (magnification 1000x), and the maximum width of the surface crystal grains 32 in a field of view of 85 μm x 120 μm was measured three times, and the maximum value among the three measurements was taken as the maximum width W.

[0033] Furthermore, in the metal plate 30 of this embodiment, the protruding height H of the engaging protrusion 36 is set to 0.1 μm or more. The protruding height H of the engaging protrusion 36 can be measured by observing a cross section along the thickness direction of the plate body 31, as shown in Figure 2(b), and is the distance from a reference line connecting the valley bottoms on both sides of the engaging protrusion 36 (the dashed line in Figure 2(b)) to the top of the engaging protrusion 36. More specifically, a cross section along the thickness direction of the roughened plating layer 35 was observed by SEM (magnification 5000 times), and for all engaging protrusions observed in a field of view of 16 μm × 23 μm, the distance from a reference line connecting the valley bottoms on both sides of each engaging protrusion to the top of the engaging protrusion was measured, and the average of the obtained values ​​was taken as the protruding height H of the engaging protrusion in the field of view of 16 μm × 23 μm. This was performed three times, and the average was taken as the protruding height H of the engaging protrusion.

[0034] As shown in FIG. 3, in the insulating circuit board 10 of this embodiment, the insulating resin layer 12 engages with the engaging protrusion 36 of the circuit layer 13 (metal plate material 30) at the bonding interface between the insulating resin layer 12 and the circuit layer 13, and the circuit layer 13 (metal plate material 30) and the insulating resin layer 12 are interdigitated with each other.

[0035] 5(a), in the present embodiment, the metal substrate 11 also has a roughened plating layer 35 having the above-mentioned engaging protrusions formed on its joint surface with the insulating resin layer 12, similar to the metal plate material 30. At the joint interface between the insulating resin layer 12 and the metal substrate 11, the insulating resin layer 12 engages with the engaging protrusions of the metal substrate 11, and the metal substrate 11 and the insulating resin layer 12 are interdigitated with each other.

[0036] The reasons for specifying the number N of engaging protrusions 36 in the maximum width of surface crystal grains 32 of plate body 31, the maximum width W of the surface crystal grains, the protruding height H of the engaging protrusions, and N×H / W as described above in the metal plate material 30 constituting the circuit layer 13 of the insulating circuit board 10 of this embodiment will be explained below.

[0037] (Number N of engagement protrusions 36 in maximum width W of surface layer crystal grains 32 of plate body 31) In the metal plate 30 of this embodiment, a plurality of engaging protrusions 36 are formed on the surface crystal grains 32 of the plate body 31. Here, the number N of engaging protrusions 36 in the maximum width W of the surface crystal grains 32 of the plate body 31 refers to the number N of engaging protrusions 36 formed on the surface crystal grains 32 having the maximum width W of the plate body 31. If the number N of engaging protrusions 36 is small, there is a risk that the adhesion with the insulating resin layer 12 will be insufficient.

[0038] (Maximum width of surface grain W) In the metal plate material 30 of this embodiment, even when the maximum width W of the surface crystal grains of the plate body 31 is 3 μm or more, i.e., even when the crystal grains of the plate body 31 are coarse, a sufficient number of engaging protrusions 36 are secured, and the adhesion between the circuit layer 13 (metal plate material 30) and the insulating resin layer 12 can be improved. In particular, in this embodiment, the metal plate 30 is made of oxygen-free copper, which has excellent thermal and electrical conductivity, and therefore, although the crystal grains tend to become coarse, a sufficient number of engaging protrusions 36 can be ensured. This makes it possible to configure an insulated circuit board 10 with excellent thermal and electrical conductivity. There is no particular lower limit to the maximum width W of the surface layer crystal grains of the plate body 31. There is no particular upper limit to the maximum width W of the surface layer crystal grains of the plate body 31, but it is preferably 50 μm or less, and more preferably 25 μm or less.

[0039] (Protruding height of engaging protrusion) In the metal plate material 30 of this embodiment, when the protruding height H of the engaging convex portion 36 is 0.1 μm or more, it engages more sufficiently with the insulating resin layer 12, thereby further improving the adhesion between the circuit layer 13 and the insulating resin layer 12. In order to further improve the adhesion between the circuit layer 13 and the insulating resin layer 12, it is more preferable that the protrusion height H of the engagement convex portion 36 be 0.5 μm or more, more preferably 1.0 μm or more, and may be 2.0 μm or more. In addition, although there is no particular upper limit to the protruding height H of the engaging protrusion 36, in order to sufficiently ensure the insulation properties of the insulating resin layer 12, it is preferable that the protruding height H of the engaging protrusion 36 be 15.0 μm or less, more preferably 10.0 μm or less, and even more preferably 6.0 μm or less.

[0040] (N × H / W) In the metal plate 30 of this embodiment, a plurality of engaging protrusions 36 are formed on the surface crystal grains 32 of the plate body 31. Here, with respect to the protruding height H (unit: μm) of the engaging protrusions 36, the maximum width W (unit: μm) of the surface crystal grains 32, and the number N of the engaging protrusions 36 in the maximum width W of the surface crystal grains 32, if N×H / W is less than 0.5, the number of the engaging protrusions 36 in the maximum width W of the surface crystal grains 32 is insufficient or the protruding height of the engaging protrusions 36 is insufficient, which may result in insufficient adhesion to the insulating resin layer 12. For this reason, in this embodiment, the value of N×H / W at the maximum width W of the surface layer crystal grains 32 of the plate body 31 is set to 0.5 or more. In order to further improve the adhesion between the circuit layer 13 (metal plate material 30) and the insulating resin layer 12, it is preferable that the N×H / W value of the plate body 31 be 1.0 or more, and it is even more preferable that it be 2.0 or more. Although there is no upper limit to the value of N×H / W of the plate body 31, the value of N×H / W is about 10 or less.

[0041] Next, a method for manufacturing the insulating circuit board 10 according to this embodiment will be described with reference to FIG. 4 through FIG. 5(a) to FIG. 5(d).

[0042] (Surface roughening process S01) First, in the metal sheet material 30 that will become the circuit layer 13, a roughened plating layer 35 is formed on the surface of the sheet body 31. In this embodiment, the roughened plating layer 35 is also formed on the metal substrate 11 (see FIG. 5(a)). The roughened plating layer 35 is formed as follows. An electrolytic plating process is performed on the joint surface of the plate body 31 (and the metal substrate 11). In this embodiment, it is preferable to use an electrolytic solution consisting of an aqueous solution of disodium 3,3'-dithiobis(1-propanesulfonate) added to a copper sulfate bath mainly composed of copper sulfate (CuSO4) and sulfuric acid (H2SO4) as the electrolytic plating solution. In addition, it is preferable to set the temperature of the plating bath within a range of, for example, 25°C to 35°C.

[0043] The electrolytic plating process is first performed by a direct current electrolytic plating method, and then by a PR (Periodic Reverse) pulse electrolytic plating method. In the DC electrolytic plating method, the current density is 1A / dm 2 More than 20A / dm 2 The voltage is within the range below, and the application time is within the range of 10 seconds to 120 seconds. Here, the electrolytic plating process is first performed using a direct current electrolytic plating method, and then using a PR pulse electrolytic plating method, so that even if the surface crystal grains of the plate body 31 are large, fine engagement protrusions 36 can be formed in a dispersed manner on the surface of the large surface crystal grains.

[0044] The PR pulse electrolytic plating method is a method of electrolytic plating in which the direction of the current is periodically reversed. For example, 1A / dm 2 More than 30A / dm 2 The following positive electrolysis (anodic electrolysis with the plate body 31 (and the metal substrate 11) as the anode) is performed for 1 ms to 1000 ms at 1 A / dm 2 More than 30A / dm 2 The following negative electrolysis (negative electrolysis with the plate body 31 (and metal substrate 11) as the negative electrode) is performed for 1 ms to 1000 ms, and this is repeated. As a result, dissolution of the surface of the plate body 31 (and metal substrate 11) and precipitation of copper are repeated, and a roughened plating layer 35 is formed.

[0045] Here, the number of engagement protrusions 36 in the roughened plating layer 35 can be adjusted by the surface properties of the plate body 31 (and the metal substrate 11) on which the roughened plating layer 35 is formed, and various plating conditions (pulse application time, pulse waveform (ratio of deposition amount / dissolution amount), pulse frequency). For example, by lengthening the pulse application time or adjusting the ratio of deposition amount / dissolution amount as the pulse waveform, the size of the engagement protrusions 36 having the widened portion 36a whose width gradually increases toward the tip side in the protruding direction can be increased. Also, by adjusting the pulse frequency, the number of engagement protrusions 36 can be increased.

[0046] (Lamination process S02) Next, a resin composition 22 containing boron nitride as a filler, an epoxy resin as a thermosetting resin, and a curing agent is disposed on one surface (the upper surface in FIG. 5(b)) of the metal substrate 11. In this embodiment, the resin composition 22 is formed into a sheet shape. Moreover, a metal sheet 30 which will become the circuit layer 13 is disposed on one surface of this resin composition 22 (the upper surface in FIG. 5(b)). The resin composition 22 is laminated on the surfaces of the metal substrate 11 and the metal sheet material 30 on which the roughened plating layer 35 is formed.

[0047] (Thermocompression bonding process S03) Next, as shown in FIG. 5(b), the laminated metal substrate 11, resin composition 22, and metal sheet material 30 are pressurized in the stacking direction to harden the resin composition 22 to form the insulating resin layer 12, and to bond the metal substrate 11 and the insulating resin layer 12, and the insulating resin layer 12 and the metal sheet material 30 together (see FIG. 5(c)). The conditions for this thermocompression step S03 are preferably a heating temperature in the range of 150° C. to 400° C., a holding time at the heating temperature in the range of 15 minutes to 90 minutes, and a pressure in the lamination direction in the range of 1 MPa to 100 MPa.

[0048] (Circuit pattern formation process S04) Next, the metal plate material 30 joined to the insulating resin layer 12 is etched to form a circuit pattern, thereby forming the circuit layer 13.

[0049] In this manner, the insulating circuit board 10 of this embodiment is manufactured as shown in FIG. 5(d).

[0050] (Heat sink bonding process S05) Next, the heat sink 41 is joined to the other surface of the metal substrate 11 of the insulating circuit board 10. In this embodiment, the metal substrate 11 and the heat sink 41 are joined via a solder material.

[0051] (Semiconductor element bonding process S06) Then, the semiconductor element 3 is bonded to the circuit layer 13 of the insulating circuit board 10. In this embodiment, the circuit layer 13 and the semiconductor element 3 are bonded via a solder material. Through the above steps, the power module 1 shown in FIG. 1 is manufactured.

[0052] According to the metal sheet material 30 and insulating circuit board 10 (laminate) of this embodiment configured as described above, the roughened plating layer 35 formed on the outermost layer of the plate body 31 has an engaging protrusion 36 formed therein, which protrudes toward the side opposite the plate body 31 and has a widened portion 36a whose width gradually increases toward the tip side in the protruding direction. Therefore, at the bonding interface between the circuit layer 13 (metal sheet material 30) and the insulating resin layer 12, the engaging protrusion 36 of the circuit layer 13 (metal sheet material 30) engages with the insulating resin layer 12, making it possible to improve the adhesion between the circuit layer 13 (metal sheet material 30) and the insulating resin layer 12.

[0053] Furthermore, since the ratio of the number of engaging protrusions 36 to the maximum width W of the surface crystal grains 32 is set to 0.4 pieces / μm or more, even if the crystal grains of the plate body 31 are coarse, the engaging protrusions 36 can be formed sufficiently, making it possible to improve the adhesion between the circuit layer 13 (metal plate material 30) and the insulating resin layer 12.

[0054] In this embodiment, even if the maximum width W of the surface crystal grains 32 of the circuit layer 13 (metal sheet material 30) is coarsened to 3 μm or more, the engagement protrusions 36 can be sufficiently formed, and it is possible to improve the adhesion between the circuit layer 13 (metal sheet material 30) and the insulating resin layer 12. Furthermore, the plate body 31 can be made of a metal with relatively coarse crystal grains (oxygen-free copper in this embodiment), and the thermal conductivity and electrical conductivity of the plate body 31 can be improved.

[0055] In this embodiment, when the protruding height H of the engaging convex portion 36 is set to 0.1 μm or more, the adhesion between the circuit layer 13 (metal plate material 30) and the insulating resin layer 12 can be further improved.

[0056] Furthermore, according to the manufacturing method for the metal sheet material of this embodiment, in the surface roughening step S01 for forming a roughened plating layer on the surface of the sheet body, an electrolytic plating process is performed on the joint surface of the sheet body 31 (and the metal substrate 11). The electrolytic plating process is first performed by a direct current electrolytic plating method and then by a PR pulse electrolytic plating method. Therefore, even if the surface crystal grains of the sheet body 31 are large, fine engaging protrusions 36 can be formed in a dispersed manner on the surface of the large surface crystal grains.

[0057] Although the embodiment of the present invention has been described above, the present invention is not limited to this, and can be modified as appropriate without departing from the technical concept of the invention. In this embodiment, the insulating circuit board is manufactured by the method for manufacturing an insulating circuit board shown in FIG. 4 and FIG. 5(a) to FIG. 5(d), but the present invention is not limited to this.

[0058] In addition, in this embodiment, the metal plate material forming the circuit layer has been described as being made of oxygen-free copper, but the present invention is not limited to this, and may be made of other copper or copper alloys, or may be made of other metals such as aluminum or aluminum alloys. Furthermore, the metal plate material may have a structure in which a plurality of metals are laminated.

[0059] Furthermore, in this embodiment, the metal substrate is described as being made of oxygen-free copper, but is not limited thereto, and may be made of other copper or copper alloy, or may be made of other metal such as aluminum or aluminum alloy, or may have a structure in which a plurality of metals are laminated.

[0060] In the present embodiment, a power module is configured by mounting a semiconductor element on an insulating circuit board, but the present invention is not limited to this. For example, an LED module may be configured by mounting an LED element on a circuit layer of an insulating circuit board, or a thermoelectric module may be configured by mounting a thermoelectric element on a circuit layer of an insulating circuit board. EXAMPLES

[0061] The results of experiments carried out to confirm the effects of the present invention will be described below.

[0062] A metal substrate (40 mm x 40 mm x 2 mm thick) made of a rolled sheet of oxygen-free copper and a metal sheet material (40 mm x 40 mm x 0.5 mm thick) to be a circuit layer were prepared, and a roughened plating layer was formed on the bonding surface of the metal substrate and the metal sheet material with the insulating resin layer by the DC electrolytic plating method and the PR pulse electrolytic plating method described in the above embodiment. The plating conditions for Examples 1 to 7 and Comparative Examples 1 and 2 are shown in Table 1.

[0063] Then, a sheet material (40 mm×40 mm×0.15 mm thick) of a resin composition containing an epoxy resin containing boron nitride as a filler was placed on the surface of the metal substrate on which the roughened plating layer was formed. A metal plate material to become a circuit layer was laminated on one surface of the sheet material of the resin composition such that the surface on which the roughened plating layer was formed faced the sheet material side of the resin composition.

[0064] The metal substrate, the resin composition sheet material, and the metal plate material laminated as described above were heated while being pressed in the lamination direction, the resin composition was cured to form an insulating resin layer, and the metal substrate and the insulating resin layer, and the insulating resin layer and the metal plate material were bonded to obtain an insulating circuit substrate. The pressure in the lamination direction was 10 MPa, the heating temperature was 180°C, and the holding time at the heating temperature was 60 minutes. The metal sheets and insulating circuit boards of Examples 1 to 7 and Comparative Examples 1 and 2 obtained as described above were evaluated for the following items.

[0065] (Maximum width W of the surface grain of the metal plate) The cross section of the metal sheet material on which the roughened plating layer was formed was observed in the thickness direction by SEM (magnification 1000 times), and the maximum width W of the surface layer crystal grains located on the outermost surface of the sheet surface was measured. The maximum width W was measured at the interface between the sheet body and the roughened plating layer. That is, the interface between the sheet body and the roughened plating layer, observed at a cross section along the thickness direction of the sheet body and the roughened plating layer, was observed with a scanning electron microscope (SEM) (magnification 1000x), and the maximum width of the surface crystal grains in a field of view of 85 μm × 120 μm was measured three times, and the maximum value among the three measurements is shown in Table 1 as the maximum width W.

[0066] (Protruding height H of engaging protrusion) A cross section along the thickness direction of the metal sheet material on which the roughened plating layer was formed was observed with an SEM (magnification: 5000 times), and the protruding height H of the engaging convex portion was measured. That is, a cross section along the thickness direction of the roughened plating layer was observed by SEM (magnification 5000 times), and for all engaging protrusions observed in a field of view of 16 μm × 23 μm, the distance from a reference line connecting the valley bottoms on both sides of the engaging protrusion to the top of the engaging protrusion was measured, and the average of the obtained values ​​was taken as the protruding height of the engaging protrusion in a field of view of 16 μm × 23 μm. This was performed three times, and the average value was shown in Table 1 as the protruding height H of the engaging protrusion.

[0067] (Number of engagement protrusions present on the surface grain with the widest width N) A cross section along the thickness direction of the metal sheet material on which a roughened plating layer was formed was observed with an SEM (magnification of 1000 to 5000 times), and the number N of engaging protrusions present in the surface crystal grain with the maximum width was measured. That is, the interface between the plate body and the roughened plating layer, observed at a cross section along the thickness direction of the plate body and the roughened plating layer, was observed with a scanning electron microscope (SEM) (magnification 1000 to 5000 times), and the number of engaging protrusions present in the surface crystal grain with the maximum width was measured. This is shown in Table 1 as the number N of engaging protrusions at the maximum width W.

[0068] (N × H / W) N×H / W was calculated from the maximum width W of the surface crystal grain located on the outermost surface of the plate surface measured as described above, the number N of engaging protrusions present on the surface crystal grain with the widest width, and the protruding height H of the engaging protrusions.

[0069] (Adhesion evaluation) A 90-degree peel test was carried out in accordance with JIS K 6854-1:1999 to confirm the location of peeling and evaluate the adhesion between the insulating resin layer and the circuit layer. The evaluation results are shown in Table 1.

[0070] [Table 1]

[0071] In Comparative Example 1, only the PR pulse electrolytic plating method was performed without performing the DC electrolytic plating method, and the value of N×H / W was 0.31. As a result of evaluating the adhesion, peeling occurred at the bonding interface between the insulating resin layer and the circuit layer, and the adhesion between the insulating resin layer and the circuit layer was insufficient. In Comparative Example 2, only the PR pulse electrolytic plating method was performed without performing the DC electrolytic plating method, and the value of N×H / W was 0.35. As a result of evaluating the adhesion, peeling occurred at the bonding interface between the insulating resin layer and the circuit layer, and the adhesion between the insulating resin layer and the circuit layer was insufficient.

[0072] In Examples 1 to 7 of the present invention, a roughened plating layer was formed by performing a direct current electrolytic plating method and then a PR pulse electrolytic plating method, and the value of N×H / W was 0.5 or more. As a result of evaluating the adhesion, peeling occurred inside the insulating resin layer, and the adhesion between the insulating resin layer and the circuit layer was excellent.

[0073] From the above experimental results, it has been confirmed that the present invention can provide a metal plate material having excellent adhesion to a laminated resin member, a laminate in which this metal plate material and a resin member are laminated, and an insulated circuit board. [Explanation of symbols]

[0074] 10 Insulated circuit board (laminate) 12 Insulating resin layer (resin material) 13 circuit layer 30 Metal plate material

Claims

1. A metal plate material made of copper or a copper alloy, The plate has a plate body and a roughening plating layer formed on the outermost surface of the plate body, The roughened plating layer is provided with an engaging protrusion having a widened portion that protrudes toward the opposite side of the plate body and gradually widens toward the tip end in the protruding direction, A metal plate material characterized in that, in a cross section along the thickness direction of the plate body, a plurality of engaging protrusions are formed on surface crystal grains located on the outermost surface of the plate body, and N×H / W is 0.5 or more, where W (unit: μm) is the maximum width of the surface crystal grain, N is the number of engaging protrusions in the maximum width of the surface crystal grain, and H (unit: μm) is the protruding height of the engaging protrusions.

2. 2. The metal plate material according to claim 1, wherein the maximum width of the surface layer crystal grains is 3 μm or more.

3. 3. The metal plate material according to claim 1, wherein the engaging protrusions have a protruding height of 0.1 μm or more.

4. A laminate in which a resin member is laminated on a plate surface of the metal plate material according to any one of claims 1 to 3, A laminate comprising: at a joint interface between the resin member and the metal plate, the resin member engages with the engaging protrusion of the metal plate.

5. An insulating circuit board comprising an insulating resin layer and a circuit layer formed on one surface of the insulating resin layer, the circuit layer is formed by bonding the metal plate material according to any one of claims 1 to 3 to one surface of the insulating resin layer, An insulating circuit board, characterized in that, at a bonding interface between the insulating resin layer and the circuit layer, the insulating resin layer engages with the engaging protrusions of the metal plate material.

6. A method for producing the metal plate material according to any one of claims 1 to 3, A method for manufacturing a metal sheet material, comprising the steps of: performing direct current electrolytic plating on the sheet body; and then performing PR pulse electrolytic plating to form the roughened plating layer on the outermost surface of the sheet body.

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