Manufacturing method of substrate

Abstract

To provide a manufacturing method of a substrate capable of suppressing reduction of an insulation property of an insulation layer.SOLUTION: A manufacturing method of a substrate 100 includes: an insulation material arrangement step S10 of arranging an insulation material 2 on one face of a base substrate 10; a circuit layer arrangement step S20 of arranging a circuit layer 30 on a table 200 including a first recess 210 corresponding to the circuit layer 30; and an insulation layer formation step S30 of forming an insulation layer 20 fixing the circuit layer 30 to the base substrate 10 by curing the insulation material 2 by mutually pressing the table 200, on which the circuit layer 30 is arranged, and the base substrate 10 in a state where at least a part of the insulation material 2 is opposed to the circuit layer 30, and heating the insulation material 2.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a substrate.

[0002] In the field of power modules, etc., a substrate is used which has a circuit layer that mounts a semiconductor element and contributes to heat dissipation of the mounted semiconductor element, and an insulating layer that holds the circuit layer and electrically insulates the circuit layer. As a method for forming the substrate, there is a method in which a press is used to punch out the circuit layer from a metal plate, the punched circuit layer is attached to an insulating material, and the insulating material is then cured to form the circuit layer and the insulating layer.

[0003] Patent Document 1 describes a method for manufacturing a substrate, which includes processing a metal plate, providing a cutout portion to form a circuit pattern portion, and bonding the circuit pattern portion to a heat dissipation layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-123984 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned method, the circuit layer exerts a large pressure on the insulating layer, so that the circuit layer is likely to bite into the insulating layer, which may cause a decrease in the insulating properties of the insulating layer.

[0006] An example of an object of the present invention is to provide a method for manufacturing a substrate that can suppress deterioration of the insulating properties of an insulating layer.

[0007] According to the present invention, there is provided a method for manufacturing a substrate as described below.

[0008] [1] an insulating material disposing step of disposing an insulating material on one surface of a base substrate; a circuit layer placement step of placing a circuit layer on a platform having a first recess corresponding to the circuit layer; an insulating layer formation process in which the base on which the circuit layer is arranged and the base substrate are pressed against each other with at least a portion of the insulating material facing the circuit layer, and the insulating material is heated to harden the insulating material and form an insulating layer that fixes the circuit layer to the base substrate. [2] a difference between a thickness of the circuit layer and a depth of the first recess is 50% or less of a thickness of the insulating layer; A method for manufacturing the substrate described in [1]. [3] The thickness of the circuit layer is greater than the depth of the first recess. A method for manufacturing a substrate according to [2]. [4] The platform is A second recess; a fitting member fitted in the second recess and having the first recess; Equipped with A method for manufacturing a substrate according to any one of [1] to [3]. [5] The base substrate has a heat dissipation protrusion on a surface opposite to the one surface. A method for manufacturing a substrate according to any one of [1] to [4]. [6] In the insulating layer forming step, a pressing member having a pressing protrusion that is higher than the heat dissipation protrusion is prepared; a portion of a surface of the base substrate opposite to the one surface, the portion being different from the heat dissipation protrusion, is pressed by the pressurizing protrusion, thereby pressing the base substrate toward a platform; A method for manufacturing a substrate according to [5]. [7] the base substrate has a plurality of the heat dissipation protrusions, The portion different from the heat dissipation protrusions is a portion between the heat dissipation protrusions. A method for manufacturing a substrate according to [6]. [8] The area of ​​the region where the pressurizing protrusion and the surface opposite to the one surface are in contact with each other is the area of ​​the surface of the base substrate opposite to the one surface. 20% or more, A method for producing a substrate according to [6] or [7]. [9] The area of ​​a bottom surface of the first recess is 30% or more of the area of ​​the one surface of the base substrate. A method for manufacturing a substrate according to any one of [1] to [8].

[10] The base has a release layer disposed on at least a part of a bottom surface of the first recess. A method for manufacturing a substrate according to any one of [1] to [9].

[11] The release layer is a release film. A method for manufacturing a substrate according to

[10] .

[12] The release layer contains a fluororesin. A method for producing a substrate according to

[10] or

[11] .

[13] In the insulating material arrangement step, the insulating material has a reaction rate calculated from a measurement result of a DSC (differential scanning calorimeter) of more than 0% and not more than 60%. A method for manufacturing a substrate according to any one of [1] to

[12] . Effect of the Invention

[0009] It is possible to provide a method for manufacturing a substrate that can suppress deterioration of the insulating properties of an insulating layer. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram showing an example of a cross section of a substrate according to the embodiment. [Diagram 2] 11A and 11B are diagrams showing modified cross sections of a substrate according to the embodiment; [Diagram 3] 3A to 3C are cross-sectional process diagrams illustrating a method for manufacturing a substrate according to the present embodiment. [Figure 4] 5A to 5C are cross-sectional process views illustrating a first modified example of the method for manufacturing a substrate according to the present embodiment. [Diagram 5] 5A to 5C are cross-sectional process views illustrating a second modified example of the method for manufacturing a substrate according to the present embodiment. [Figure 6] 13 is a diagram showing a stage in a third modified example of the method for manufacturing a substrate according to the present embodiment. FIG. [Figure 7] 6A to 6C are cross-sectional process views illustrating a third modified example of the method for manufacturing a substrate according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In all drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Note that the drawings are for explanatory purposes only. The shapes and dimensional ratios of the components in the drawings do not necessarily correspond to the actual products.

[0012] In this specification, the expression "a to b" in the explanation of a numerical range means from a to b, unless otherwise specified. For example, "1% by mass to 5% by mass" means "1% by mass to 5% by mass."

[0013] [Outline of the substrate 100] FIG. 1 is a diagram showing an example of a cross section of a substrate 100 according to the present embodiment. The substrate 100 includes a base substrate 10, an insulating layer 20, and a circuit layer 30. The insulating layer 20 is disposed on one surface of the base substrate 10. The circuit layer 30 for mounting a semiconductor element is disposed on one surface of the insulating layer 20 opposite the base substrate 10. As shown in FIG. 2, the base substrate 10 may have a heat dissipation protrusion 11, with a heat dissipation fin or a radiator attached to the surface opposite the insulating layer 20. The total thickness T0 of the substrate 100 when the base substrate 10 has the heat dissipation protrusion 11 is not particularly limited, but is preferably 2 mm or more and 20 mm or less, and more preferably 3 mm or more and 15 mm or less. Each configuration will be described in detail below.

[0014] <Base substrate 10> The base substrate 10 holds the insulating layer 20. As described above, the base substrate 10 may have a heat dissipation fin, a radiator, or the like attached to the surface opposite the insulating layer 20, and may have a heat dissipation protrusion 11. In this case, the heat dissipation performance of the substrate 10 is improved. The heat dissipation protrusion 11 may be integrated with the base substrate 10.

[0015] The material constituting the base substrate 10 may be, for example, one or a combination of two or more selected from copper, copper alloys, aluminum, and aluminum alloys. Among these, it is preferable that at least one of copper and aluminum is included from the viewpoint of strength. Furthermore, when the base substrate 10 is made of copper, it is preferable that the base substrate 10 is covered with a plating metal such as nickel plating, silver plating, or gold plating. In this case, the corrosion resistance of the base substrate 10 is improved.

[0016] The thickness T1 of the base substrate 10 excluding the heat dissipation protrusions 11 is not particularly limited, but is preferably 40% or more and 90% or less of the total thickness T0.

[0017] The upper limit of the thickness T1 is, for example, 18 mm or less, preferably 15 mm or less, and more preferably 12 mm or less. When the thickness T1 is set to this value or less, the substrate 100 becomes thinner and the processability of the substrate 100 in the outer shape processing, cutting processing, and the like is improved.

[0018] Furthermore, the lower limit of the thickness T1 is, for example, 1 mm or more, preferably 1.5 mm or more, and more preferably 2 mm or more. When the thickness T1 is set to this value or more, the heat dissipation properties of the substrate 100 can be improved.

[0019] <Insulating layer 20> The material constituting the insulating layer 20 according to this embodiment is, for example, a thermosetting resin. The thermosetting resin may be one or a combination of two or more selected from the group consisting of epoxy resin, phenol resin, urea resin, melamine resin, polyester (unsaturated polyester) resin, polyimide resin, silicone resin, and polyurethane resin.

[0020] It is preferable to mix a filler containing particles having electrical insulation properties and high thermal conductivity into the insulating layer 20. As a constituent material of the particles of such a filler, for example, at least one of a metal oxide such as alumina and a nitride such as boron nitride can be used.

[0021] The thickness T2 of the insulating layer 20 is appropriately set according to the purpose, but from the viewpoint of more efficiently transferring heat from the semiconductor element to the base substrate 10, the lower limit is preferably 50 μm or more, and more preferably 80 μm or more. From the viewpoint of the strength of the substrate 100, the upper limit is preferably 300 μm or less, and more preferably 200 μm or less.

[0022] Furthermore, the insulating layer 20 according to this embodiment preferably has a thermal conductivity of 3 W / (m·K) or more, more preferably 7 W / (m·K) or more, and even more preferably 12 W / (m·K) or more, thereby improving the heat dissipation properties of the substrate 10.

[0023] <Circuit layer 30> The circuit layer 30 is, for example, mounted with a semiconductor element. The circuit layer 30 is made of a metal material having electrical conductivity. The metal material constituting the circuit layer 30 may be, for example, one or a combination of two or more metals selected from copper, copper alloys, aluminum, and aluminum alloys. This allows the circuit layer 30 to have a relatively small resistance value. It is more preferable that the circuit layer 30 is a copper-containing layer that contains copper.

[0024] The lower limit of the thickness T3 of the circuit layer 30 is, for example, 0.3 mm or more, preferably 0.5 mm or more, and more preferably 1 mm or more. The upper limit of the thickness T3 of the circuit layer 30 is, for example, 4 mm or less, preferably 3 mm or less, and more preferably 2 mm or less. The manufacturing method of the substrate 100 according to the present embodiment, which will be described later, can form a circuit layer 30 having a thickness equal to or greater than the above lower limit. Furthermore, by making the thickness T3 of the circuit layer 30 equal to or greater than the above lower limit, heat generation of the substrate 100 can be suppressed even in applications requiring high current. Furthermore, by making the thickness T3 of the circuit layer 30 equal to or less than the above upper limit, the manufacturing method of the substrate 100 according to the present embodiment can be easily applied.

[0025] [Method of manufacturing the substrate 100] Next, a method for manufacturing the substrate 100 according to the present embodiment will be described with reference to Fig. 3. Fig. 3 is a cross-sectional process diagram showing the method for manufacturing the substrate 100 according to the present embodiment. The method for manufacturing the substrate 100 according to the present embodiment includes an insulating material arrangement step S10 for arranging an insulating material 2 on one surface of the base substrate 10, a circuit layer arrangement step S20 for arranging the circuit layer 30 on a platform 200 having a first recess 210 corresponding to the circuit layer 30, and an insulating layer formation step S30 for forming an insulating layer 20 for fixing the circuit layer 30 to the base substrate 10 by pressing the platform 200 on which the circuit layer 30 is arranged and the base substrate 10 against each other with at least a part of the insulating material 2 facing the circuit layer 30 and heating the insulating material 2 to harden the insulating material 2.

[0026] <Insulating material arrangement process S10> The insulating material disposing step S10 is a step of disposing the insulating material 2 on the base substrate 10. The insulating material disposing step S10 is performed, for example, by disposing an insulating sheet, in which the insulating material 2 is formed into a sheet shape, on the base substrate 10. The insulating material 2 is preferably in a B-stage state. The B-stage state means that the reaction rate of the insulating layer 20 calculated from the measurement results of a DSC (differential scanning calorimeter) is more than 0% and 60% or less. The insulating material 2 in the B-stage state is in a semi-cured state and has adhesiveness, so that it is semi-fixed after being disposed on the base substrate 10. As a result, the insulating material 2 is held without being separated from the base substrate 10 even if the base substrate 10 is turned upside down in a step described later.

[0027] <Circuit layer placement process S20> The circuit layer arrangement step S20 is a step of arranging the circuit layer 30 on a base 200 having a first recess 210 corresponding to the circuit layer 30. The base 200 is, for example, a metal mold. The first recess 210 is a region into which the circuit layer 30 is fitted. In addition, the difference between the thickness T3 of the circuit layer 30 and the depth T4 of the first recess 210 is preferably 50% or less of the thickness T2 of the insulating layer 20, and more preferably 30% or less of the thickness T2 of the insulating layer 20. This reduces the step between the base 200 and the circuit layer 30, so that in the insulating layer formation step S30 described later, when the circuit layer 30 is pressed against the insulating material 2, the difference between the pressure received from the region of the base 200 where the first recess 210 is not formed and the pressure received from the circuit layer 30 is reduced, and the circuit layer 30 can be prevented from being embedded in the insulating material 2.

[0028] Furthermore, it is preferable that the thickness T3 of the circuit layer 30 is greater than the depth T4 of the first recess 210. This ensures sufficient pressure from the circuit layer 30 to the insulating material 2, thereby improving the adhesion of the circuit layer 30 to the insulating layer 20 (insulating material 2).

[0029] In order to prevent the circuit layer 30 from shifting in the insulating layer forming step S30, it is preferable that the shape of the circuit layer 30 and the shape of the first recess 210 are substantially the same when viewed in the thickness direction. However, in order to make it easier to fit the circuit layer 30 into the first recess 210, the shape of the first recess 210 is slightly larger. Specifically, the shape of the first recess 210 has a play width of about 50 μm.

[0030] Moreover, it is preferable that the shape of the bottom surface 211 of the first recess 210 conforms to the shape of the upper surface 31 of the circuit layer 30. Specifically, it is preferable that the shape of both the bottom surface 211 of the first recess 210 and the shape of the upper surface 31 of the circuit layer 30 are flat.

[0031] Moreover, the area of ​​the bottom surface 211 of the first recess 210 is preferably 30% or more, and more preferably 40% or more, of the area of ​​the first surface of the base substrate 10 on which the insulating material 2 is disposed. This allows the circuit pattern formed by the circuit layer 30 to be integrated, and the entire substrate 100 to be made smaller.

[0032] <Insulating layer forming process S30> In the insulating layer forming step S30, the base 200 on which the circuit layer 30 is arranged and the base substrate 10 are pressed against each other with at least a part of the insulating material 2 facing the circuit layer 30, and the insulating material 2 is heated. The insulating layer forming step S30 is performed, for example, at high temperature by arranging the base substrate 10 on the base substrate 10 so that at least a part of the insulating material 2 arranged on the base substrate 10 faces the circuit layer 30 on the base substrate 200 on which the circuit layer 30 is fitted, and then pressing the surface of the base substrate 10 opposite the insulating material 2 with the pressing member 300. As a result, the insulating material 2 is heated and hardened to form the insulating layer 20, and the circuit layer 30 is fixed to the base substrate 10 and the insulating layer 20. The insulating layer forming step S30 is performed, for example, by arranging the base substrate 200, the circuit layer 30, the insulating material 2, the base substrate 10, and the pressing member 300 in this order from the bottom.

[0033] According to the manufacturing method for the substrate 100 according to the present embodiment, when the circuit layer 30 is pressed against the insulating material 2, both pressure from the base 200 and pressure from the circuit layer 30 are applied to the insulating material 2, thereby preventing the circuit layer 30 from being embedded in the insulating material 2. In addition, when the insulating material 2 hardens, the circuit layer 30 is fitted and fixed in the first recess 210, thereby preventing the circuit layer 30 from being displaced due to thermal contraction of the insulating material 2.

[0034] As described above, according to the manufacturing method of the substrate 100 of this embodiment, the base 200 and the circuit layer 30 press against the insulating material 2, so that the pressure applied to the circuit layer 30 is reduced, thereby preventing the circuit layer 30 from penetrating into the insulating material 2.

[0035] Next, a first modified example of the manufacturing method of the substrate 100 will be described with reference to Fig. 4. The first modified example is a manufacturing method particularly preferred when the base substrate 10 has a heat dissipation fin, a radiator, or the like attached to the surface opposite to the surface on which the insulating material 2 of the base substrate 10 is arranged, and has a heat dissipation protrusion 11. In this case, since the heat dissipation protrusion 11 is easily deformed by pressure, it is preferred to press the base substrate 10 without contacting the heat dissipation protrusion 11.

[0036] In the first modified example, the pressure member 300 has a pressure protrusion 310. The pressure protrusion 310 is a protrusion that is taller than the heat dissipation protrusion 11. The pressure protrusion 310 presses a specific portion of the base substrate 10, for example, a portion different from the heat dissipation protrusion 11. In other words, the pressure member 300 can press the base substrate 10 without coming into contact with the heat dissipation protrusion 11.

[0037] Moreover, the area of ​​contact between the pressurizing protrusion 310 and the base substrate 10 is preferably 20% or more, and more preferably 40% or more, of the area of ​​one surface (upper surface in FIG. 4) of the base substrate 10 with which it comes into contact. This makes it possible to uniformize the pressure applied to each circuit layer 30.

[0038] Furthermore, when the base substrate 10 has a plurality of heat dissipation protrusions 11, the portion different from the heat dissipation protrusions 11 is, for example, a portion between the heat dissipation protrusions 11. For example, when the portion between the heat dissipation protrusions 11 is pressed, the pressure applied to each circuit layer 30 can be made uniform.

[0039] As described above, according to the first modified example, even if the base substrate 10 has a heat dissipation convex portion 11, it is possible to press a portion of the base substrate 10 other than the heat dissipation convex portion 11 (press the base substrate 10 without contacting the heat dissipation convex portion 11).

[0040] Next, a second modified example of the method for manufacturing the substrate 100 will be described with reference to FIG. 5. In the second modified example, in the circuit layer arrangement step S20, before arranging the circuit layer 30 in the first recess 210, a release layer 3 for facilitating removal of the circuit layer 30 is arranged in the first recess 210. This allows the circuit layer 30 to be easily removed after it is pressed in the insulating layer formation step S30. The release layer 3 is arranged, for example, on the bottom surface 211 of the first recess 210. The release layer 3 may be formed, for example, by a general coating method, or may be formed by arranging a sheet-like release sheet. The materials constituting the release layer 3 and the release sheet are not particularly limited, but are preferably, for example, fluororesin.

[0041] As described above, according to the second modified example, after the circuit layer 30 is pressed in the insulating layer forming process S30, the circuit layer 30 can be easily removed, thereby preventing the contact between the circuit layer 30 and the insulating layer 20 from coming off when the circuit layer 30 is removed.

[0042] Next, a third modified example of the method for manufacturing the substrate 100 will be described with reference to Figures 6 and 7. Figure 6 is a diagram showing a base 200 in the third modified example. In the third modified example, the base 200 includes a second recess 220 and an engagement member 230 that is engaged in the second recess 220 and has a first recess 210. The base 200 in the third modified example is capable of replacing the engagement member 230. This allows the base 200 to change the shape of the first recess 210, and can be used to form circuit layers 30 with various patterns.

[0043] 7 is a cross-sectional process diagram showing a manufacturing method of the substrate 100 in the third modified example. As shown in Fig. 7, in the third modified example, an inlay member arranging step S15 is performed before the circuit layer arranging step S20. In the inlay member arranging step S15, an inlay member 230 corresponding to the circuit layer 30 to be formed is selected and arranged in the second recess 220.

[0044] As described above, according to the third modified example, by simply replacing a portion of the base 200 (the fitting member 230), it is possible to form circuit layers 30 with various patterns.

[0045] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted. [Explanation of symbols]

[0046] 100 Substrates 200 units 210 First recess 220 Second recess 230 Insertion parts 300 Pressure member 310 Pressurizing protrusion 10 Base Board 11 Heat dissipation protrusion 20 Insulating layer 30 circuit layers

Claims

1. an insulating material disposing step of disposing an insulating material on one surface of a base substrate; a circuit layer placement step of placing a circuit layer on a platform having a first recess corresponding to the circuit layer; an insulating layer formation process in which the base on which the circuit layer is arranged and the base substrate are pressed against each other with at least a portion of the insulating material facing the circuit layer, and the insulating material is heated to harden the insulating material and form an insulating layer that fixes the circuit layer to the base substrate.

2. a difference between a thickness of the circuit layer and a depth of the first recess is 50% or less of a thickness of the insulating layer; A method for manufacturing the substrate according to claim 1 .

3. The thickness of the circuit layer is greater than the depth of the first recess. The method for manufacturing the substrate according to claim 2 .

4. The platform is A second recess; a fitting member fitted in the second recess and having the first recess; Equipped with The method for manufacturing the substrate according to claim 1 .

5. The base substrate has a heat dissipation protrusion on a surface opposite to the one surface. The method for manufacturing the substrate according to claim 1 .

6. In the insulating layer forming step, a pressing member having a pressing protrusion that is higher than the heat dissipation protrusion is prepared; a portion of a surface of the base substrate opposite to the one surface, the portion being different from the heat dissipation protrusion, is pressed by the pressurizing protrusion, thereby pressing the base substrate toward a platform; The method for manufacturing the substrate according to claim 5 .

7. the base substrate has a plurality of the heat dissipation protrusions, The portion different from the heat dissipation protrusions is a portion between the heat dissipation protrusions. The method for manufacturing a substrate according to claim 6 .

8. The area of ​​the region where the pressurizing protrusion and the surface opposite to the one surface are in contact with each other is the area of ​​the surface of the base substrate opposite to the one surface. 20% or more, The method for manufacturing a substrate according to claim 6 .

9. an area of ​​a bottom surface of the first recess is 30% or more of an area of ​​the one surface of the base substrate; The method for manufacturing the substrate according to claim 1 .

10. The base has a release layer disposed on at least a part of a bottom surface of the first recess. The method for manufacturing the substrate according to claim 1 .

11. The release layer is a release film. The method for manufacturing a substrate according to claim 10 .

12. The release layer contains a fluororesin. The method for manufacturing a substrate according to claim 10 .

13. In the insulating material arrangement step, the insulating material has a reaction rate calculated from a measurement result of a DSC (differential scanning calorimeter) of more than 0% and not more than 60%. The method for manufacturing the substrate according to claim 1 .

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