Method for manufacturing printed circuit board

Abstract

In the production of a printed circuit board (1), first, a metal support substrate (2) is prepared. Next, a base insulating layer (3) is formed on one surface in the thickness direction of the metal support substrate (2). Next, a conductor layer (4) is formed on one surface in the thickness direction of the base insulating layer (3). Then, in the step of preparing the metal support substrate (2), the metal support substrate (2) is preheated.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a wiring circuit substrate. BACKGROUND

[0002] In the past, a suspension substrate has a metal support substrate, a base insulating layer formed on the metal support substrate, a plurality of wirings formed on the base insulating layer, and a cover layer covering the wirings. In the suspension substrate, as the metal support substrate, a metal material having higher electric conductivity than stainless steel is used, and more specifically, a copper alloy type spring material is used (for example, refer to Patent Literature 1).

[0003] PRIOR ART DOCUMENT PATENT LITERATURE Patent Literature 1: Japanese Patent Application Laid-Open No. 2013-168206 SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION In the manufacturing of the suspension substrate, it is required to align the base insulating layer, the wirings, and the cover layer with respect to the metal support substrate with excellent precision.

[0005] However, in the manufacturing of the suspension substrate described above, there is a case where the metal support substrate is heated. For example, in the formation of the base insulating layer, there is a case where the resin as the material of the base insulating layer is heated, and at the same time, the metal support substrate is heated.

[0006] In such a case, the size of the metal support substrate changes due to the heating, and specifically, shrinks. As a result, there is a case where the precision of the alignment is reduced.

[0007] The present application is a manufacturing method of a wiring circuit substrate capable of performing alignment with relatively excellent precision.

[0008] TECHNICAL SOLUTION FOR SOLVING THE PROBLEMS The present application [1] includes a manufacturing method of a wiring circuit substrate, which has: a step of preparing a metal support substrate; a step of forming a base insulating layer on one face in the thickness direction of the metal support substrate; and a step of forming a conductor layer on one face in the thickness direction of the base insulating layer, the step of preparing the metal support substrate including a step of preheating the metal support substrate.

[0009] In the manufacturing method of the wiring circuit substrate of the above [1], the metal support substrate is preheated in the step of preparing the metal support substrate before the step of forming the base insulating layer and the step of forming the conductor layer. That is, the size of the metal support substrate is changed in advance by heating. Therefore, by using such a metal support substrate, it is possible to suppress the change in the size of the metal support substrate in the step of forming the base insulating layer and the step of forming the conductor layer. As a result, according to the manufacturing method of the wiring circuit substrate of the above, it is possible to perform alignment with excellent precision.

[0010] The present invention [2] includes the manufacturing method of the wiring circuit substrate of the above [1], wherein the base insulating layer contains a resin, the step of forming the base insulating layer includes a step of thermally curing a raw material of the resin to obtain the resin, and the temperature in the preheating of the metal support substrate is higher than the temperature in the thermal curing of the resin in the step of forming the base insulating layer.

[0011] In the manufacturing method of the wiring circuit substrate of the above [2], the temperature in the preheating of the metal support substrate is higher than the temperature in the thermal curing of the resin in the step of forming the base insulating layer. Therefore, according to the manufacturing method of the wiring circuit substrate of the above, it is possible to change the size of the metal support substrate in advance, and thus it is possible to suppress the change in the size of the metal support substrate in the step of forming the base insulating layer. As a result, according to the manufacturing method of the wiring circuit substrate of the above, it is possible to perform alignment with excellent precision.

[0012] The present invention [3] includes the manufacturing method of the wiring circuit substrate of the above [2], wherein the resin is a polyimide resin.

[0013] In the manufacturing method of the wiring circuit substrate of the above [3], the polyimide resin is heated to a relatively high temperature, and thus the size of the metal support substrate is likely to change. In view of this, in the manufacturing method of the wiring circuit substrate of the above, the temperature in the preheating of the metal support substrate is higher than the temperature in the thermal curing of the polyimide resin. Therefore, according to the manufacturing method of the wiring circuit substrate of the above, it is possible to change the size of the metal support substrate in advance, and thus it is possible to suppress the change in the size of the metal support substrate in the step of forming the base insulating layer. As a result, according to the manufacturing method of the wiring circuit substrate of the above, it is possible to perform alignment with excellent precision.

[0014] The present application [4] includes the manufacturing method of the wiring circuit substrate described in any one of the above [1] to [3], wherein the manufacturing method of the wiring circuit substrate further includes a step of forming a cover insulating layer containing a resin on one face of the base insulating layer and the thickness direction of the conductor layer, the step of forming the cover insulating layer includes a step of thermally curing a raw material of the resin to obtain the resin, and the temperature in the preheating of the metal support substrate is higher than the temperature in the thermal curing of the step of forming the cover insulating layer.

[0015] In the manufacturing method of the wiring circuit substrate described in the above [4], the temperature in the preheating of the metal support substrate is higher than the temperature in the thermal curing of the resin of the step of forming the cover insulating layer. Therefore, according to the manufacturing method of the wiring circuit substrate described above, the dimensional change of the metal support substrate can be made in advance, and thus the dimensional change of the metal support substrate in the step of forming the cover insulating layer can be suppressed. As a result, according to the manufacturing method of the wiring circuit substrate described above, the alignment can be performed with excellent precision.

[0016] The present application [5] includes the manufacturing method of the wiring circuit substrate described in any one of the above [1] to [4], wherein the metal support substrate contains a copper alloy.

[0017] In the manufacturing method of the wiring circuit substrate described in the above [5], the dimensional change of the metal support substrate easily occurs in the case where the metal support substrate contains a copper alloy. In view of this, in the manufacturing method of the wiring circuit substrate described above, the dimensional change of the metal support substrate is made in advance by heating. Therefore, by using such a metal support substrate, the dimensional change of the metal support substrate in the step of forming the base insulating layer and the step of forming the conductor layer can be suppressed. As a result, according to the manufacturing method of the wiring circuit substrate described above, the alignment can be performed with excellent precision.

[0018] The present application [6] includes the manufacturing method of the wiring circuit substrate described in any one of the above [1] to [5], wherein the metal support substrate is a rolled metal.

[0019] In the manufacturing method of the wiring circuit substrate described in the above [6], the dimensional change of the metal support substrate easily occurs in the case where the metal support substrate is a rolled metal. In view of this, in the manufacturing method of the wiring circuit substrate described above, the dimensional change of the metal support substrate is made in advance by heating. Therefore, by using such a metal support substrate, the dimensional change of the metal support substrate in the step of forming the base insulating layer and the step of forming the conductor layer can be suppressed. As a result, according to the manufacturing method of the wiring circuit substrate described above, the alignment can be performed with excellent precision.

[0020] The present application [7] includes the manufacturing method of the wiring circuit substrate described in any one of the above [1] to [6], wherein the thickness of the metal support substrate is 100 μm or less.

[0021] In the manufacturing method of the wiring circuit substrate described in the above [7], the thickness of the metal support substrate is a given value or less. That is, the metal support substrate is relatively thin. In such a case, the size of the metal support substrate is likely to change. In view of this, in the manufacturing method of the wiring circuit substrate described above, the size of the metal support substrate is changed in advance by heating. By using such a metal support substrate, it is thereby possible to suppress the change in the size of the metal support substrate in the process of forming the base insulating layer and the process of forming the conductor layer. As a result, according to the manufacturing method of the wiring circuit substrate described above, it is possible to perform alignment with excellent precision.

[0022] The present application [8] includes the manufacturing method of the wiring circuit substrate described in any one of the above [1] to [7], wherein, in the process of preparing the metal support substrate, the metal support substrate is wound around a preheating core, and the metal support substrate in a state of being wound around the preheating core is subjected to the preheating.

[0023] In the manufacturing method of the wiring circuit substrate described in the above [8], by preheating the metal support substrate in a state of being wound around the preheating core, it is thereby possible to more easily change the size of the metal support substrate in advance by heating. Therefore, according to the manufacturing method of the wiring circuit substrate described above, it is possible to more easily suppress the change in the size of the metal support substrate in the process of forming the base insulating layer and the process of forming the conductor layer. As a result, according to the manufacturing method of the wiring circuit substrate described above, it is possible to perform alignment with excellent precision.

[0024] The present application [9] includes the manufacturing method of the wiring circuit substrate described in any one of the above [1] to [8], wherein, in the process of preparing the metal support substrate, the metal support substrate is subjected to the preheating while being conveyed by a roll-to-roll method.

[0025] In the manufacturing method of the wiring circuit substrate described in the above [9], by preheating the metal support substrate while being conveyed by a roll-to-roll method, it is thereby possible to more efficiently change the size of the metal support substrate in advance by heating. Therefore, according to the manufacturing method of the wiring circuit substrate described above, it is possible to more efficiently suppress the change in the size of the metal support substrate in the process of forming the base insulating layer and the process of forming the conductor layer. As a result, according to the manufacturing method of the wiring circuit substrate described above, it is possible to perform alignment with excellent precision.

[0026] Effects of the Invention The wiring circuit board manufacturing method according to the present invention enables alignment with relatively excellent precision. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of a wiring circuit board obtained according to an embodiment of the manufacturing method of the wiring circuit board according to the present invention.

[0028] Figure 2A This indicates the process of preparing the metal support substrate. Figure 2B This indicates the process of preheating the metal support substrate. Figure 2C This refers to the process of forming a substrate insulating layer on one side in the thickness direction of a metal support substrate. Figure 2D This indicates the process of forming a conductor layer on one side of the substrate insulating layer in the thickness direction. Figure 2E This refers to the process of forming a covering insulating layer on one side in the thickness direction of the substrate insulating layer and the conductor layer. Detailed Implementation

[0029] 1. Wiring circuit board (1) Overall structure The following is for reference Figure 1 A wiring circuit board obtained by an embodiment of the manufacturing method of the wiring circuit board according to the present invention will be described.

[0030] exist Figure 1 In this circuit, the wiring circuit substrate 1 has a thickness. The wiring circuit substrate 1 extends along the surface direction. The surface direction is orthogonal to the thickness direction. The wiring circuit substrate 1 has a plate shape. The thickness of the wiring circuit substrate 1 is, for example, 10 μm or more. In addition, the thickness of the wiring circuit substrate 1 is, for example, 500 μm or less, preferably 300 μm or less, and more preferably 200 μm or less.

[0031] exist Figure 1 In the circuit board 1, the wiring circuit board 1 includes: a metal support substrate 2; a base insulating layer 3 disposed on one side of the metal support substrate 2 in the thickness direction; a conductor layer 4 disposed on one side of the base insulating layer 3 in the thickness direction; and a cover insulating layer 5 disposed on one side of the base insulating layer 3 in the thickness direction to cover the conductor layer 4.

[0032] The wiring circuit board 1 includes multiple segments 11A and 11B. Segments 11A and 11B are respectively disposed on one side of the metal support substrate 2 in the thickness direction. Segments 11A and 11B are divided in the planar direction. Segments 11B are spaced apart from segments 11A in the planar direction. Segment 11A includes a base insulating layer 3A, a conductor layer 4A, and a cover insulating layer 5A. Segment 11B includes a base insulating layer 3B, a conductor layer 4B, and a cover insulating layer 5B.

[0033] (2) Metal support substrate The metal support substrate 2 is provided at the other end portion of the wiring circuit substrate 1 in the thickness direction. The metal support substrate 2 forms the other end surface of the wiring circuit substrate 1 in the thickness direction. The metal support substrate 2 extends in the surface direction. Each of one surface and the other surface of the metal support substrate 2 in the thickness direction is a flat surface. The metal support substrate 2 is in contact with the other surface of the division body 11A, 11B in the thickness direction.

[0034] The metal support substrate 2 is composed of, for example, a metal, and preferably a metal obtained by rolling by a publicly known method (hereinafter referred to as a rolled metal).

[0035] As the metal, for example, stainless steel and a copper alloy can be given. They can be used alone or in combination of two or more. As the metal, a copper alloy is preferable. In other words, the metal support substrate 2 preferably contains a copper alloy, and more preferably is composed of a copper alloy.

[0036] The copper alloy is an alloy containing copper. The copper alloy contains a first metal composed of copper, and a second metal that can be alloyed with copper. The alloyable indicates that an alloy can be formed. The alloy can be a solid solution, a eutectic, an intermetallic compound, or a composite thereof.

[0037] In the copper alloy, the second metal is an additive metal added to copper as the first metal. That is, the second metal indicates a metal other than copper. As the second metal, for example, titanium, nickel, and silicon can be given. They can be used alone or in combination of two or more. That is, the copper alloy can be a two-component alloy, or an alloy of three or more components. The second metal is preferably titanium. In the case where the second metal is titanium, the copper alloy is a copper-titanium alloy. In the case where the copper-titanium alloy is used, the wiring circuit substrate 1 has more excellent mechanical strength.

[0038] In the copper alloy, the content ratio of the first metal (i.e., copper) and the second metal is appropriately set according to the purpose and use.

[0039] In the copper alloy, the content ratio of the first metal (i.e., copper (the same hereinafter)) and the content ratio of the second metal (preferably titanium (the same hereinafter)) are appropriately set according to the purpose and use.

[0040] More specifically, the atomic ratio of the first metal is, for example, 50 to 99%, preferably 80 to 99%, and more preferably 90 to 99%, with respect to the total amount (total number of atoms) of the copper alloy.

[0041] In addition, the atomic ratio of the second metal is, for example, 1 to 50%, preferably 1 to 20%, and more preferably 1 to 10%, with respect to the total amount (total number of atoms) of the copper alloy.

[0042] It should be noted that in copper alloys, the total atomic ratio of the first metal and the second metal is, for example, 100 atoms.

[0043] In addition, based on mass, the mass ratio of the first metal relative to the total mass of the copper alloy (total mass) is, for example, 50 to 99 by mass, preferably 80 to 99 by mass, and more preferably 90 to 99 by mass.

[0044] In addition, based on mass, the mass ratio of the second metal relative to the total mass of the copper alloy (total mass) is, for example, 1 to 50% by mass, preferably 1 to 20% by mass, and more preferably 1 to 10% by mass.

[0045] It should be noted that in copper alloys, the total mass ratio of the first metal to the second metal is, for example, 100 by mass.

[0046] In the metal support substrate 2, the copper alloy preferably has a phase-separated structure. Examples of phase-separated structures include nanosheet structures and island structures, with island structures being more preferred. That is, the copper alloy is more preferably equipped with an island structure.

[0047] The island structure comprises: a marine portion (i.e., marine phase) having a continuous shape; and an island portion (i.e., island phase) having a discontinuous shape. More specifically, a copper alloy with an island structure comprises: a marine portion having a relatively high proportion of a first metal and a relatively low proportion of a second metal; and an island portion having a relatively low proportion of the first metal and a relatively high proportion of the second metal. The copper alloy with the island structure is obtained, for example, by preheating a copper alloy with a nanosheet structure (described later).

[0048] Copper alloys possess relatively high mechanical strength. The tensile strength of the aforementioned copper alloys is, for example, 800 MPa or more, preferably 900 MPa or more. The tensile strength of the aforementioned copper alloys is, for example, 2000 MPa or less, preferably 1700 MPa or less. That is, the tensile strength of the copper alloys is, for example, 800 MPa or more and 2000 MPa or less, preferably 900 MPa or more and 1700 MPa or less. It should be noted that the tensile strength of the copper alloys was measured according to JIS Z 2241 (2011).

[0049] Furthermore, the aforementioned copper alloy exhibits high electrical conductivity. For example, when the copper alloy has been rolled, the conductivity of the copper alloy at 20°C in the rolling direction (MD direction) is, for example, 30% IACS or less, preferably 20% IACS or less, and more preferably 15% IACS or less. Additionally, the conductivity of the copper alloy at 20°C in the rolling direction (MD direction) is, for example, 1% IACS or more, preferably 5% IACS or more. That is, the conductivity of the copper alloy at 20°C in the rolling direction (MD direction) is, for example, 1% IACS or more and 30% IACS or less, preferably 5% IACS or more and 20% IACS or less, and more preferably 5% IACS or more and 15% IACS or less.

[0050] Furthermore, when the copper alloy has already been rolled, the conductivity of the copper alloy at 20°C in the direction orthogonal to the rolling direction (TD direction) is, for example, 30% IACS or less, preferably 20% IACS or less, and more preferably 15% IACS or less. Additionally, the conductivity of the copper alloy at 20°C in the direction orthogonal to the rolling direction (TD direction) is, for example, 1% IACS or more, preferably 5% IACS or more. That is, the conductivity of the copper alloy at 20°C in the direction orthogonal to the rolling direction (TD direction) is, for example, 1% IACS or more and 30% IACS or less, preferably 5% IACS or more and 20% IACS or less, and more preferably 5% IACS or more and 15% IACS or less.

[0051] It should be noted that IACS stands for International Annealed Copper Standard, and the conductivity is measured according to JIS H 0505 (1975) and JIS H 0500 (1998).

[0052] The metal support substrate 2 is relatively thin. The thickness of the metal support substrate 2 is, for example, 100 μm or less, preferably 90 μm or less, and more preferably 75 μm or less. Furthermore, the thickness of the metal support substrate 2 is typically 25 μm or more. That is, the thickness of the metal support substrate 2 is, for example, 25 μm or more and 100 μm or less, preferably 25 μm or more and 90 μm or less, and more preferably 25 μm or more and 75 μm or less.

[0053] (3) Substrate insulation layer A substrate insulating layer 3 is disposed on one surface of the metal support substrate 2 in the thickness direction. The substrate insulating layer 3 extends along the surface direction. One surface of the substrate insulating layer 3 in the thickness direction is a flat surface. The substrate insulating layer 3 has a patterned shape. Specifically, the substrate insulating layer 3 includes a plurality of substrate insulating layers 3A and 3B. Each of the substrate insulating layers 3A and 3B is contained within the aforementioned partitions 11A and 11B.

[0054] As the base insulating layer 3, resin (i.e., a cured resin) can be cited as an example. That is, the base insulating layer 3 preferably contains resin, and more preferably is composed of resin. As the resin, for example, thermosetting resins can be cited; more specifically, examples include polyimide resins, polyamide-imide resins, acrylic resins, polyether nitrile resins, polyethersulfone resins, polyethylene terephthalate resins, polyethylene naphthalate resins, and polyvinyl chloride resins, with polyimide resins being the most preferred. That is, the above-mentioned resins are preferably polyimide resins.

[0055] The base insulating layer 3 is formed, for example, by thermally curing the raw material of the aforementioned resin. It should be noted that details regarding the thermal curing of the resin raw material will be described later.

[0056] The thickness of the substrate insulating layer 3 is, for example, 1 μm or more, preferably 3 μm or more. Alternatively, the thickness of the substrate insulating layer 3 is, for example, 30 μm or less, preferably 20 μm or less.

[0057] (4) Conductor layer Conductor layer 4 is disposed on one surface of the substrate insulating layer 3 in the thickness direction. Conductor layer 4 extends along the surface direction. In this embodiment, conductor layer 4 has a generally rectangular shape in cross-section. One surface of conductor layer 4 in the thickness direction is a flat surface.

[0058] Conductor layer 4 includes multiple wirings and terminals. The wirings can be clock wirings, differential wirings, or other types of wirings. In this embodiment, the wirings are differential wirings. Differential wirings are paired wirings having a pair (i.e., two) signal lines. The signal wirings are arranged substantially parallel to each other, forming a signal transmission line. Terminals are formed at both ends of each wiring along its length. The wirings and terminals are disposed on one surface of each of the substrate insulating layers 3A and 3B in the thickness direction.

[0059] The material for conductor layer 4 can be, for example, a conductive metal, specifically copper. Additionally, the terminal portion (not shown) is plated using known methods as needed, and furthermore, heat-treated as required. Details regarding the heat treatment will be described later.

[0060] (5) Cover with insulation layer The cover insulating layer 5 is disposed on one surface of the base insulating layer 3 in the thickness direction, such that it covers the conductor layer 4. The cover insulating layer 5 forms one surface of the wiring circuit board 1 in the thickness direction. The cover insulating layer 5 extends along the surface direction.

[0061] The covering insulating layer 5 has a patterned shape. Specifically, the covering insulating layer 5 includes multiple covering insulating layers 5A and 5B. Each of the covering insulating layers 5A and 5B is contained within the aforementioned dividers 11A and 11B. Each of the covering insulating layers 5A and 5B is arranged on one side of each of the base insulating layers 3A and 3B in a manner that covers the wiring of the conductor layer 4.

[0062] In this embodiment, the end face of the covering insulating layer 5 (each of the covering insulating layers 5A and 5B) in the width direction is flush with the end face of the base insulating layer 3 (each of the base insulating layers 3A and 3B) in the width direction.

[0063] As the covering insulating layer 5, examples include the same resin (i.e., a cured resin) as the resin exemplified as the base insulating layer 3. That is, the covering insulating layer 5 preferably contains resin, and more preferably is composed of resin. Examples of resins include thermosetting resins, and more specifically, examples include polyimide resins, polyamide-imide resins, acrylic resins, polyether nitrile resins, polyethersulfone resins, polyethylene terephthalate resins, polyethylene naphthalate resins, and polyvinyl chloride resins, with polyimide resins being the most preferred. That is, the above-mentioned resins are preferably polyimide resins.

[0064] The insulating layer 5 is formed, for example, by thermally curing the resin raw material described above. Details regarding the thermal curing of the resin raw material will be described later.

[0065] The thickness of the covering insulating layer 5 is, for example, 1 μm or more, preferably 3 μm or more. Alternatively, the thickness of the covering insulating layer 5 is, for example, 30 μm or less, preferably 20 μm or less.

[0066] It should be noted that the thickness of the covering insulation layer 5 is the length in the thickness direction between one face of the base insulation layer 3 in the thickness direction and one face of the covering insulation layer 5 in the thickness direction that is opposite to the aforementioned face without being separated by the conductor layer 4.

[0067] The combined thickness of the covering insulating layer 5 and the base insulating layer 3 is, for example, 80 μm or less, preferably 50 μm or less, and more preferably 40 μm or less. Alternatively, the combined thickness of the covering insulating layer 5 and the base insulating layer 3 is, for example, 5 μm or more.

[0068] 2. Manufacturing method of wiring circuit board Hereinafter, an embodiment of the method for manufacturing the wiring circuit board of the present invention will be described with reference to FIG2.

[0069] (1) Metal support substrate In the manufacturing of the wiring circuit board 1, firstly, as referred to Figures 2A-2B Therefore, prepare the metal support substrate 2.

[0070] More specifically, in this process, as referred to Figure 2A Therefore, firstly, an unheated (described later) metal support substrate 2 is prepared. Hereinafter, the unheated (described later) metal support substrate 2 will be referred to as blank 20. Blank 20 is obtained, for example, as a commercially available product. Blank 20 is, for example, a copper alloy obtained by rolling. In addition, blank 20 is, for example, made of a copper alloy having a nanosheet structure.

[0071] Next, in this method, as referred to Figure 2B In this way, the blank 20 is preheated to obtain the preheated metal support substrate 2. Hereinafter, the preheated metal support substrate 2 will be referred to as the heated substrate 21. It should be noted that the details of the preheating will be described later.

[0072] (2) Substrate insulation layer Next, in this method, as referred to Figure 2C In this way, a base insulating layer 3 is formed on one side of the heated substrate 21 in the thickness direction.

[0073] There are no particular limitations on the method for forming the substrate insulating layer 3. For example, firstly, a varnish containing the raw material of the aforementioned resin is prepared. The varnish, for example, contains a photosensitizer, the raw material of the resin, and a solvent. The raw material of the aforementioned resin is a compound used to obtain the aforementioned resin (i.e., the cured resin), and is an uncured resin component. The raw material of the resin is appropriately selected depending on the type of resin. For example, when the resin is a polyimide resin, examples of raw materials for the resin include dianhydrides and diamines.

[0074] More specifically, when the base insulating layer 3 is composed of polyimide resin, the varnish contains a photosensitizer, dianhydride and diamine, and a solvent. Their proportions are appropriately set according to the purpose and application.

[0075] Next, in this method, the aforementioned varnish is applied to one side of the metal support substrate 2 in the thickness direction, and dried by heating, thereby forming a photosensitive coating film. The coating film contains polyamic acid resin. Polyamic acid resin is a raw material for polyimide resin. More specifically, polyamic acid resin is a reaction product of acid dianhydride and diamine, and is an intermediate raw material (i.e., precursor) for polyimide resin.

[0076] In the process of forming the substrate insulating layer 3, the drying temperature is, for example, 50°C or higher and 200°C or lower. The drying time is, for example, 1 minute or higher and 60 minutes or lower.

[0077] Next, in this method, the coating is exposed and developed to form a given pattern. Then, in this method, the resin raw material is thermally cured to obtain a resin. More specifically, the coating with the given pattern (preferably a polyamic acid resin used as a raw material for polyimide resin) is thermally cured by heating to obtain a base insulating layer 3.

[0078] In the process of forming the substrate insulating layer 3, the thermosetting temperature is, for example, 100°C or higher, preferably 200°C or higher. Furthermore, in the process of forming the substrate insulating layer 3, the thermosetting temperature is, for example, 500°C or lower, preferably 450°C or lower. That is, the thermosetting temperature is, for example, 100°C or higher and 500°C or lower, preferably 200°C or higher and 450°C or lower.

[0079] The heat curing time is, for example, more than 1 hour and less than 10 hours.

[0080] Through the above steps, the substrate insulating layer 3 is disposed on one side of the metal support substrate 2 in the thickness direction.

[0081] (3) Conductor layer Next, in this method, as referred to Figure 2D In this way, a conductor layer 4 is formed on one side in the thickness direction of the substrate insulating layer 3.

[0082] There are no particular limitations on the method for forming conductor layer 4, and well-known conductor patterning methods can be used. Examples of conductor patterning methods include additive, semi-additive, and subtractive methods, with additive methods being preferred.

[0083] In addition, although not shown in the figure, the terminal portion of the conductor layer 4 can be plated as needed in this method, and the conductor layer 4 can also be heat-treated.

[0084] Through the above steps, the conductor layer 4 is disposed on one side of the substrate insulating layer 3 in the thickness direction.

[0085] (4) Cover with insulation layer Next, in this method, as referred to Figure 2E In this way, a covering insulating layer 5 is formed on one side of the substrate insulating layer 3 and the conductor layer 4 in the thickness direction.

[0086] There are no particular limitations on the method of forming the covering insulating layer 5. For example, the covering insulating layer 5 can be formed by the same method as the method of forming the base insulating layer 3 described above.

[0087] More specifically, for example, firstly, a varnish comprising the above-mentioned resin is prepared. The varnish, for example, contains a photosensitizer, the above-mentioned resin, and a solvent.

[0088] More specifically, when the insulating layer 5 is made of polyimide resin, the varnish contains a photosensitizer, dianhydride and diamine, and a solvent. Their proportions are appropriately determined according to the purpose and application.

[0089] Next, in this method, the varnish is applied to one side along the thickness direction of the substrate insulating layer 3 and the conductor layer 4, and dried by heating, thereby forming a photosensitive coating film. The coating film contains polyamic acid resin. Polyamic acid resin is a raw material for polyimide resin. More specifically, polyamic acid resin is a reaction product of acid dianhydride and diamine, and is an intermediate raw material (i.e., precursor) for polyimide resin.

[0090] In the process of forming the covering insulating layer 5, the drying temperature is, for example, 50°C or higher and 200°C or lower. The drying time is, for example, 1 minute or higher and 60 minutes or lower.

[0091] Next, in this method, the coating is exposed and developed to form a given pattern. Then, in this method, the resin raw material is thermally cured to obtain a resin. More specifically, the coating of the given pattern (preferably a polyamic acid resin as a raw material for polyimide resin) is thermally cured by heating to obtain a covering insulating layer 5.

[0092] In the process of forming the covering insulating layer 5, the thermosetting temperature is, for example, 100°C or higher, preferably 200°C or higher. Furthermore, in the process of forming the covering insulating layer 5, the thermosetting temperature is, for example, 500°C or lower, preferably 450°C or lower. That is, the thermosetting temperature is, for example, 100°C or higher and 500°C or lower, preferably 200°C or higher and 450°C or lower. The thermosetting time is, for example, 1 hour or more and 10 hours or less.

[0093] Through the above steps, the covering insulating layer 5 is disposed on one side of the base insulating layer 3 and the conductor layer 4 in the thickness direction. More specifically, on one side of the base insulating layer 3 in the thickness direction, the covering insulating layer 5 covers the wiring of the conductor layer 4 and exposes the terminal portion (not shown).

[0094] In addition, in the above-mentioned processes, the metal support substrate 2, the base insulating layer 3, the conductor layer 4, and the covering insulating layer 5 are aligned with each other to manufacture the wiring circuit substrate 1 (refer to...). Figure 1 ).

[0095] 3. Preheating In the above-described method for manufacturing the wiring circuit board 1, the metal support substrate 2 is heated. More specifically, in the above method, during the formation of the base insulating layer 3, the varnish is heated and thermally cured. At this time, the metal support substrate 2 is heated together with the varnish. Additionally, in the above method, if necessary, the conductor layer 4 may be heat-treated. At this time, the metal support substrate 2 is heated together with the conductor layer 4. Furthermore, in the above method, during the formation of the covering insulating layer 5, the varnish is heated and thermally cured. At this time, the metal support substrate 2 is heated together with the varnish.

[0096] In this situation, the dimensions of the metal support substrate 2 change due to heating, specifically shrinking. As a result, the alignment accuracy of the metal support substrate 2, the base insulating layer 3, the conductor layer 4, and the covering insulating layer 5 is reduced.

[0097] Therefore, in order to suppress the dimensional changes (i.e., shrinkage) of the metal support substrate 2, in the above-described method for manufacturing the wiring circuit board 1, the metal support substrate 2 (i.e., the blank 20) ​​is preheated during the preparation of the metal support substrate 2. Then, the preheated metal support substrate 2 (i.e., the heated substrate 21) is sequentially laminated with a base insulating layer 3, a conductor layer 4, and a cover insulating layer 5.

[0098] More specifically, in the above method, in the process of preparing the metal support substrate 2, the blank 20 is preheated to obtain the heated substrate 21 (preheating process).

[0099] There are no particular limitations on the method of preheating the metal support substrate 2. For example, although not shown, the blank 20 can be preheated by winding the blank 20 around a preheating core and placing the blank 20 wound around the preheating core in a heating furnace.

[0100] Preheating conditions are selected, for example, based on the heating temperature of the substrate insulating layer 3.

[0101] More specifically, as described above, the substrate insulating layer 3 is preferably made of resin, and the process of forming the substrate insulating layer 3 includes a process of thermally curing the resin raw material to obtain the resin. In this case, during the thermal curing of the resin raw material, there is a possibility of dimensional changes (i.e., shrinkage) in the metal support substrate 2.

[0102] Therefore, in the above-described method for manufacturing the wiring circuit board 1, in order to suppress changes in the size of the metal support substrate 2, it is preferable to adjust the temperature during the preheating of the blank 20 to be higher than the temperature during the thermosetting of the resin raw material.

[0103] More specifically, as described above, in the process of forming the substrate insulating layer 3, the thermosetting temperature is, for example, 100°C or higher, preferably 200°C or higher. Furthermore, in the process of forming the substrate insulating layer 3, as described above, the thermosetting temperature is, for example, 500°C or lower, preferably 450°C or lower. That is, the thermosetting temperature is, for example, 100°C or higher and 500°C or lower, preferably 200°C or higher and 450°C or lower.

[0104] Here, the preheating temperature of the metal support substrate 2 is higher than the thermosetting temperature in the process of forming the base insulating layer 3, for example, 110°C or higher, preferably 120°C or higher. Furthermore, the preheating temperature of the metal support substrate 2 is, for example, 700°C or lower, preferably 600°C or lower. That is, the preheating temperature is, for example, 110°C or higher and 700°C or lower, preferably 120°C or higher and 600°C or lower.

[0105] Furthermore, the difference between the thermosetting temperature in the process of forming the base insulating layer 3 and the preheating temperature of the metal support substrate 2 is, for example, 10°C or more, preferably 20°C or more. Additionally, the difference between the thermosetting temperature in the process of forming the base insulating layer 3 and the preheating temperature of the metal support substrate 2 is, for example, 200°C or less, preferably 100°C or less. That is, the difference between the thermosetting temperature in the process of forming the base insulating layer 3 and the preheating temperature of the metal support substrate 2 is, for example, 10°C or more and 200°C or less, preferably 20°C or more and 100°C or less.

[0106] In addition, the preheating conditions are preferably selected in a manner that corresponds to the heating temperature of the conductor layer 4.

[0107] More specifically, as described above, the conductor layer 4 can be heat-treated as needed. In such cases, during the heat treatment of the conductor layer 4, there is a possibility of dimensional changes (i.e., shrinkage) in the metal support substrate 2.

[0108] Therefore, in the above-described method for manufacturing the wiring circuit board 1, in order to suppress changes in the size of the metal support substrate 2, it is preferable to adjust the temperature during the preheating of the blank 20 to be higher than the heat treatment temperature of the conductive layer 4.

[0109] In addition, the preheating conditions are preferably selected in a manner that corresponds to the heating temperature of the covering insulation layer 5.

[0110] More specifically, as described above, the covering insulating layer 5 is preferably made of resin, and the process of forming the covering insulating layer 5 includes a process of heat-curing the resin raw material to obtain the resin. In this case, during the heat curing of the resin raw material, there is a possibility of dimensional changes (i.e., shrinkage) in the metal support substrate 2.

[0111] In the above-described method for manufacturing the wiring circuit board 1, in order to suppress changes in the dimensions of the metal support substrate 2, it is preferable to adjust the temperature during the preheating of the blank 20 to be higher than the temperature during the thermosetting of the resin raw material.

[0112] More specifically, as described above, in the process of forming the covering insulating layer 5, the thermosetting temperature is, for example, 100°C or higher, preferably 200°C or higher. Furthermore, in the process of forming the covering insulating layer 5, the temperature is, for example, 500°C or lower, preferably 450°C or lower. That is, the thermosetting temperature is, for example, 100°C or higher and 500°C or lower, preferably 200°C or higher and 450°C or lower.

[0113] In contrast, the preheating temperature of the metal support substrate 2 is higher than the thermosetting temperature in the process of forming the covering insulating layer 5, as described above, for example, 110°C or higher, preferably 120°C or higher. Furthermore, the preheating temperature of the metal support substrate 2 is, for example, 700°C or lower, preferably 600°C or lower. That is, the preheating temperature is, for example, 110°C or higher and 700°C or lower, preferably 120°C or higher and 600°C or lower.

[0114] Furthermore, the difference between the thermosetting temperature in the process of forming the covering insulating layer 5 and the preheating temperature of the metal support substrate 2 is, for example, 10°C or more, preferably 20°C or more. Additionally, the difference between the thermosetting temperature in the process of forming the covering insulating layer 5 and the preheating temperature of the metal support substrate 2 is, for example, 200°C or less, preferably 100°C or less. That is, the difference between the thermosetting temperature in the process of forming the covering insulating layer 5 and the preheating temperature of the metal support substrate 2 is, for example, 10°C or more and 200°C or less, preferably 20°C or more and 100°C or less.

[0115] In addition, in this method, it is preferable to preheat the metal support substrate 2 at a temperature higher than the highest heating temperature among the heating temperatures in each step of heating the metal support substrate 2 (except for the preheating step).

[0116] In other words, the preheating temperature of the metal support substrate 2 is preferably higher than the highest temperature of each process in the manufacturing of the wiring circuit substrate 1 (except for the preheating process).

[0117] By preheating the metal support substrate 2 using this method, it is possible to suppress changes in the dimensions of the metal support substrate 2 during each step of the manufacturing process of the wiring circuit board 1 (except for the preheating step).

[0118] It should be noted that there is no particular limitation on the preheating time of the metal support substrate 2, for example, it is more than 10 minutes and less than 10 hours.

[0119] 4. Effects According to the above-described manufacturing method of the wiring circuit board 1, the metal support substrate 2, the base insulating layer 3, the conductor layer 4, and the cover insulating layer 5 can be aligned with relatively excellent precision.

[0120] More specifically, in the above-described method for manufacturing the wiring circuit board 1, the metal support substrate 2 is preheated during the preparation of the metal support substrate 2, before the steps of forming the substrate insulating layer 3 and the conductor layer 4. That is, the dimensions of the metal support substrate 2 are pre-changed by heating. Therefore, by using such a metal support substrate 2, changes in the dimensions of the metal support substrate 2 during the steps of forming the substrate insulating layer 3 and the conductor layer 4 can be suppressed. As a result, according to the above-described method for manufacturing the wiring circuit board 1, alignment can be achieved with excellent precision.

[0121] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, the temperature during the preheating of the metal support substrate 2 is higher than the temperature during the thermosetting of the resin in the process of forming the base insulating layer. Therefore, according to the above-described method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 can be changed in advance, thereby suppressing changes in the dimensions of the metal support substrate 2 during the process of forming the base insulating layer 3. As a result, according to the above-described method for manufacturing the wiring circuit board 1, alignment can be achieved with excellent precision.

[0122] Furthermore, in the aforementioned method for manufacturing the wiring circuit board 1, the polyimide resin is heated to a relatively high temperature, which easily leads to changes in the dimensions of the metal support substrate 2. To address this, in the aforementioned method for manufacturing the wiring circuit board 1, the preheating temperature of the metal support substrate 2 is higher than the thermosetting temperature of the polyimide resin. Therefore, according to the aforementioned method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 can be pre-determined, thereby suppressing changes in the dimensions of the metal support substrate 2 during the process of forming the substrate insulating layer 3. As a result, according to the aforementioned method for manufacturing the wiring circuit board 1, alignment can be achieved with excellent precision.

[0123] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, the temperature during the preheating of the metal support substrate 2 is higher than the temperature during the annealing treatment of the conductive layer 4. Therefore, according to the above-described method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 can be changed in advance, thereby suppressing changes in the dimensions of the metal support substrate 2 during the process of forming the conductor layer 4. As a result, according to the above-described method for manufacturing the wiring circuit board 1, alignment can be achieved with excellent precision.

[0124] Furthermore, in the aforementioned method for manufacturing the wiring circuit board 1, when the metal support substrate 2 is made of a copper alloy, its dimensions are prone to change. To address this, in the aforementioned method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 are pre-determined by heating. Therefore, by using such a metal support substrate 2, changes in its dimensions can be suppressed during the processes of forming the substrate insulating layer 3 and the conductor layer 4. As a result, according to the aforementioned method for manufacturing the wiring circuit board, alignment can be achieved with excellent precision.

[0125] Furthermore, in the aforementioned method for manufacturing the wiring circuit board, when the metal support substrate 2 is made of rolled metal, its dimensions are prone to change. To address this, in the aforementioned method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 are pre-determined by heating. Therefore, by using such a metal support substrate 2, changes in its dimensions can be suppressed during the processes of forming the substrate insulating layer 3 and the conductor layer 4. As a result, according to the aforementioned method for manufacturing the wiring circuit board 1, alignment can be achieved with excellent precision.

[0126] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, the thickness of the metal support substrate 2 is below a given value. That is, the metal support substrate 2 is relatively thin. Under such circumstances, the dimensions of the metal support substrate 2 are prone to change. To address this, in the above-described method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 are pre-determined by heating. By using such a metal support substrate 2, it is possible to suppress changes in the dimensions of the metal support substrate 2 during the steps of forming the substrate insulating layer 3 and forming the conductor layer 4. As a result, according to the above-described method for manufacturing the wiring circuit board 1, alignment can be achieved with excellent precision.

[0127] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, by preheating the metal support substrate 2 while it is wound in a preheating core, it is easier to pre-heat and prevent dimensional changes in the metal support substrate 2. Therefore, according to the above-described method for manufacturing the wiring circuit board 1, it is easier to suppress dimensional changes in the metal support substrate 2 during the steps of forming the substrate insulating layer 3 and forming the conductor layer 4. As a result, according to the above-described method for manufacturing the wiring circuit board 1, alignment can be achieved with excellent precision.

[0128] 5. Variations In the variations, the same reference numerals are used to mark the same components and processes as in the first embodiment, and detailed descriptions are omitted. Furthermore, unless otherwise specified, the variations can achieve the same effects as the first embodiment. Moreover, the first embodiment and its variations can be appropriately combined.

[0129] For example, in the above embodiment, the billet 20 is heat-treated by winding it around a preheating core and then placing the billet 20, wound around the preheating core, in a heating furnace. Alternatively, the billet 20 can be heat-treated by passing it through a heating furnace using a roll-to-roll method. The heat treatment conditions are the same as described above.

[0130] In the above-described method for manufacturing the wiring circuit board 1, by preheating the metal support substrate 2 while conveying it using a roller-to-roll method, the dimensional changes of the metal support substrate 2 can be more efficiently prevented through preheating. Therefore, according to the above-described method for manufacturing the wiring circuit board 1, dimensional changes of the metal support substrate 2 during the processes of forming the substrate insulating layer 3 and forming the conductor layer 4 can be more effectively suppressed. As a result, according to the above-described method for manufacturing the wiring circuit board 1, alignment can be achieved with excellent precision.

[0131] It should be noted that, although not described in detail, in the above-mentioned wiring circuit board 1, the covering insulating layer 5 is an arbitrary layer, and the covering insulating layer 5 can be omitted as needed.

[0132] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, although the substrate insulating layer 3 is directly laminated onto the metal support substrate 2, it is also possible, as needed, to indirectly laminate the substrate insulating layer 3 onto the metal support substrate 2 through an adhesive layer (not shown). In other words, the adhesive layer (not shown) can be positioned between the metal support substrate 2 and the substrate insulating layer 3. The adhesive layer (not shown) is formed by applying the adhesive (described later) to the metal support substrate 2 using a known method and then curing it using a known method.

[0133] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, although the conductor layer 4 is directly laminated onto the substrate insulating layer 3, it is also possible, as needed, to indirectly laminate the conductor layer 4 onto the substrate insulating layer 3 through an adhesive layer (not shown). In other words, the adhesive layer (not shown) can be positioned between the substrate insulating layer 3 and the conductor layer 4. The adhesive layer (not shown) is formed by applying the adhesive (described later) to the substrate insulating layer 3 using a known method and then curing it using a known method.

[0134] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, although the covering insulating layer 5 is directly laminated onto the conductor layer 4, it is also possible, as needed, to indirectly laminate the covering insulating layer 5 onto the conductor layer 4 through an adhesive layer (not shown). In other words, the adhesive layer (not shown) can be positioned between the conductor layer 4 and the covering insulating layer 5. The adhesive layer (not shown) is formed by applying the adhesive (described later) to the substrate insulating layer 3 and the conductor layer 4 using a known method and then curing it using a known method.

[0135] The aforementioned adhesive layer is a cured product of a known adhesive. Examples of adhesives include epoxy adhesives. Epoxy adhesives, for example, contain epoxy resin, a curing agent, and known additives.

[0136] The adhesive can be either a room-temperature curing adhesive or a heat-curing adhesive. When the adhesive is a room-temperature curing adhesive, by allowing the applied adhesive to stand at room temperature, an adhesive layer (not shown) consisting of the cured adhesive can be formed. When the adhesive is a heat-curing adhesive, regarding the adhesive layer, by heating the applied adhesive, an adhesive layer (not shown) consisting of the cured adhesive can be formed.

[0137] When the adhesive is a heat-curing adhesive, the heating temperature of the adhesive is, for example, 100°C or higher and 250°C or lower. Furthermore, in such cases, it is preferable that the preheating temperature of the metal support substrate 2 is higher than the heating temperature of the adhesive. More specifically, the difference between the heating temperature of the adhesive and the preheating temperature of the metal support substrate 2 is, for example, 10°C or higher and 200°C or lower, preferably 20°C or higher and 100°C or lower.

[0138] It should be noted that the above-described invention is provided as an illustrative embodiment of the present invention, but this is merely illustrative and should not be interpreted as limiting. Modifications of the invention that are obvious to those skilled in the art are included within the scope of protection of the technical solutions described below.

[0139] Industrial availability The method for manufacturing the wiring circuit board of the present invention is suitable for use in the fields of wiring circuit boards for electronic devices (wiring circuit boards for electronic components) and wiring circuit boards for electrical equipment (wiring circuit boards for electrical components).

[0140] Symbol Explanation 1: Wiring circuit board 2: Metal support substrate 3: Substrate insulation layer 4: Conductor layer 5: Cover with insulation layer 11: Segmentation 20: Billet 21: The substrate being heated.

Claims

1. A manufacturing method of a wiring circuit substrate, comprising: a step of preparing a metal support substrate; a step of forming a base insulating layer on one face in a thickness direction of the metal support substrate; and a step of forming a conductor layer on one face in a thickness direction of the base insulating layer, wherein the step of preparing the metal support substrate includes a step of preheating the metal support substrate. The base insulating layer contains a resin. The step of forming the base insulating layer includes a step of thermally curing a raw material of the resin to obtain the resin. The temperature in the preheating of the metal support substrate is higher than the temperature in the thermal curing of the step of forming the base insulating layer. The resin is a polyimide resin.

2. The manufacturing method of a wiring circuit substrate according to claim 1, wherein The manufacturing method of the wiring circuit substrate further comprises a step of forming a cover insulating layer on one face in a thickness direction of the base insulating layer and the conductor layer, The cover insulating layer contains a resin. The step of forming the cover insulating layer includes a step of thermally curing a raw material of the resin to obtain the resin.

3. The manufacturing method of a wiring circuit substrate according to claim 2, wherein The temperature in the preheating of the metal support substrate is higher than the temperature in the thermal curing of the step of forming the cover insulating layer.

4. The manufacturing method of a wiring circuit substrate according to claim 1, wherein The metal support substrate contains a copper alloy. The metal support substrate is a rolled metal. The thickness of the metal support substrate is 100 μm or less. In the step of preparing the metal support substrate, 5. The manufacturing method of a wiring circuit substrate according to claim 1, wherein The metal support substrate is wound around a preheating core.

6. The manufacturing method of a wiring circuit substrate according to claim 1, wherein The metal support substrate in a state of being wound around the preheating core is preheated.

7. The manufacturing method of a wiring circuit substrate according to claim 1, wherein In the step of preparing the metal support substrate, 8. The manufacturing method of a wiring circuit substrate according to claim 1, wherein The metal support substrate is preheated while being conveyed by a roll-to-roll method. ​ ​ 9. The manufacturing method of a wiring circuit substrate according to claim 1, wherein ​ ​

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