Manufacturing method for wiring circuit boards

Abstract

To provide a method for manufacturing a wiring circuit board that allows for relatively good alignment accuracy. [Solution] In the manufacturing of the wiring circuit board 1, first, a metal support substrate 2 is prepared. Next, a base insulating layer 3 is formed on one side in the thickness direction of the metal support substrate 2. Then, a conductor layer 4 is formed on one side in the thickness direction of the base insulating layer 3. In the process of preparing the metal support substrate 2, the metal support substrate 2 is preheated.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a wiring circuit board.

Background Art

[0002] Conventionally, a suspension substrate includes 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. Also, in the suspension substrate, a metal material having a higher conductivity than stainless steel is used as the metal support substrate, and more specifically, a copper alloy-based spring material is used (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the manufacture of a suspension substrate, it is required to align the base insulating layer, the wiring, and the cover layer with respect to the metal support substrate with excellent accuracy.

[0005] However, in the manufacture of the above suspension substrate, the metal support substrate may be heated. For example, when forming the base insulating layer, the resin which is the material of the base insulating layer may be heated, and at the same time, the metal support substrate may be heated.

[0006] In such a case, the dimensions of the metal support substrate may change due to heating, and specifically, it may shrink. As a result, the accuracy of alignment may be reduced.

[0007] The present invention is a method for manufacturing a wiring circuit board capable of alignment with relatively excellent accuracy. [Means for solving the problem]

[0008] The present invention [1] comprises the steps of preparing a metal support substrate, forming a base insulating layer on one side in the thickness direction of the metal support substrate, and forming a conductor layer on one side in the thickness direction of the base insulating layer. Equipped with, The step of preparing the metal support substrate includes a step of preheating the metal support substrate, which is part of a method for manufacturing a wiring circuit board.

[0009] The above [1] method for manufacturing a wiring circuit board includes the steps of forming a base insulating layer and forming a conductor layer of In the process of preparing the metal support substrate before the forming process, the metal support substrate is preheated. That is, the dimensions of the metal support substrate are changed in advance by heating. Therefore, by using such a metal support substrate, it is possible to suppress changes in the dimensions of the metal support substrate during the processes of forming the base insulating layer and the conductor layer. As a result, the above-described method for manufacturing a wiring circuit board allows for alignment with excellent precision.

[0010] The present invention [2] includes a method for manufacturing a wiring circuit board as described in [1] above, wherein the base insulating layer contains a resin, the step of forming the base insulating layer includes the step of obtaining the resin by thermal curing the raw materials of the resin, and the temperature during preheating of the metal support substrate is higher than the temperature during thermal curing in the step of forming the base insulating layer.

[0011] In the wiring circuit board manufacturing method described in [2] above, the temperature during preheating of the metal support substrate is higher than the temperature during the heat curing of the resin in the base insulating layer formation process. Therefore, according to the above wiring circuit board manufacturing method, the dimensions of the metal support substrate can be changed in advance, thereby suppressing changes in the dimensions of the metal support substrate during the base insulating layer formation process. As a result, the above wiring circuit board manufacturing method allows for alignment with excellent precision.

[0012] The present invention [3] includes the method for manufacturing a wiring circuit board as described in [2] above, wherein the resin is a polyimide resin.

[0013] In the method for manufacturing a wiring circuit board described in [3] above, the polyimide resin is heated to a relatively high temperature, which makes the dimensions of the metal support substrate prone to change. In contrast, in the method for manufacturing a wiring circuit board described above, the temperature during preheating of the metal support substrate is higher than the temperature during the thermosetting of the polyimide resin. Therefore, according to the method for manufacturing a wiring circuit board described above, the dimensions of the metal support substrate can be changed in advance, thereby suppressing changes in the dimensions of the metal support substrate during the process of forming the base insulating layer. As a result, the method for manufacturing a wiring circuit board described above allows for alignment with excellent precision.

[0014] The present invention [4] further includes a step of forming a cover insulating layer on one side in the thickness direction of the base insulating layer and the conductor layer, wherein the cover insulating layer contains a resin, the step of forming the cover insulating layer includes a step of obtaining the resin by thermal curing the raw material of the resin, and the temperature during preheating of the metal support substrate is higher than the temperature during thermal curing in the step of forming the cover insulating layer, the method for manufacturing a wiring circuit board according to any one of the above [1] to [3].

[0015] In the wiring circuit board manufacturing method described in [4] above, the temperature during preheating of the metal support substrate is higher than the temperature during the heat curing of the resin in the process of forming the cover insulating layer. Therefore, according to the above wiring circuit board manufacturing method, the dimensions of the metal support substrate can be changed in advance, thereby suppressing changes in the dimensions of the metal support substrate during the process of forming the cover insulating layer. As a result, the above wiring circuit board manufacturing method allows for alignment with excellent precision.

[0016] The present invention [5] includes a method for manufacturing a wiring circuit board according to any one of the above [1] to [4], wherein the metal support substrate is made of a copper alloy.

[0017] In the method for manufacturing a wiring circuit board described in [5] above, if the metal support substrate is made of a copper alloy, the dimensions of the metal support substrate are prone to change. In contrast, in the method for manufacturing a wiring circuit board described above, the dimensions of the metal support substrate are changed in advance by heating. Therefore, by using such a metal support substrate, it is possible to suppress changes in the dimensions of the metal support substrate during the process of forming the base insulating layer and the process of forming the conductor layer. As a result, the method for manufacturing a wiring circuit board described above allows for alignment with excellent precision.

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

[0019] In the method for manufacturing a wiring circuit board described in [6] above, if the metal support substrate is made of rolled metal, the dimensions of the metal support substrate are prone to change. In contrast, in the method for manufacturing a wiring circuit board described above, the dimensions of the metal support substrate are changed in advance by heating. Therefore, by using such a metal support substrate, it is possible to suppress changes in the dimensions of the metal support substrate during the process of forming the base insulating layer and the process of forming the conductor layer. As a result, the method for manufacturing a wiring circuit board described above allows for alignment with excellent precision.

[0020] The present invention [7] includes a method for manufacturing a wiring circuit board according to any one of the above [1] to [6], wherein the thickness of the metal support substrate is 100 μm or less.

[0021] In the method for manufacturing a wiring circuit board described in [7] above, the thickness of the metal support substrate is less than or equal to a predetermined value. That is, the metal support substrate is relatively thin. In such cases, the dimensions of the metal support substrate are prone to change. In contrast, in the method for manufacturing a wiring circuit board described above, the dimensions of the metal support substrate are changed in advance by heating. By using such a metal support substrate, it is possible to suppress changes in the dimensions of the metal support substrate during the process of forming the base insulating layer and the process of forming the conductor layer. As a result, the above method for manufacturing a wiring circuit board allows for alignment with excellent precision.

[0022] In the method for manufacturing a wiring circuit board according to any one of the above [1] to [7], in the step of preparing the metal support substrate, the metal support substrate is wound around a preheating core, and the metal support substrate wound around the preheating core is preheated.

[0023] In the method for manufacturing a wiring circuit board according to [8] above, by preheating the metal support substrate in a state of being wound around a preheating core, the dimensions of the metal support substrate can be more easily changed in advance by heating. Therefore, according to the method for manufacturing a wiring circuit board described above, in the step of forming the base insulating layer and the step of forming the conductor layer, it is possible to suppress changes in the dimensions of the metal support substrate. As a result, according to the method for manufacturing a wiring circuit board described above, alignment can be achieved with excellent accuracy. of In the step of forming the conductor layer, it is possible to suppress changes in the dimensions of the metal support substrate. As a result, according to the method for manufacturing a wiring circuit board described above, alignment can be achieved with excellent accuracy.

[0024] The present invention 9 includes the method for manufacturing a wiring circuit board according to any one of the above [1] to [8], in which, in the step of preparing the metal support substrate, the metal support substrate is preheated while being conveyed by a roll-to-roll method.

[0025] In the above 9 method for manufacturing a wiring circuit board, by preheating the metal support substrate while conveying it by a roll-to-roll method, the dimensions of the metal support substrate can be more efficiently changed in advance by heating. Therefore, according to the method for manufacturing a wiring circuit board described above, in the step of forming the base insulating layer and the step of forming the conductor layer, it is possible to suppress changes in the dimensions of the metal support substrate. As a result, according to the method for manufacturing a wiring circuit board described above, alignment can be achieved with excellent accuracy.

Advantages of the Invention

[0026] According to the method for manufacturing a wiring circuit board of the present invention, alignment can be achieved with relatively excellent accuracy.

Brief Description of the Drawings

[0027] [Figure 1] Figure 1 is a cross-sectional view of a wiring circuit board obtained by one embodiment of the manufacturing method for wiring circuit boards according to the present invention. [Figure 2] Figure 2A shows the process of preparing the metal support substrate, Figure 2B shows the process of preheating the metal support substrate, Figure 2C shows the process of forming a base insulating layer on one side in the thickness direction of the metal support substrate, Figure 2D shows the process of forming a conductor layer on one side in the thickness direction of the base insulating layer, and Figure 2E shows the process of forming a cover insulating layer on one side in the thickness direction of the base insulating layer and the conductor layer. [Modes for carrying out the invention]

[0028] 1. Wiring circuit board (1) Overall structure In the following, with reference to Figure 1, a wiring circuit board obtained by one embodiment of the manufacturing method for a wiring circuit board of the present invention will be described.

[0029] In Figure 1, the wiring circuit board 1 has thickness. The wiring circuit board 1 extends in the planar direction. The planar direction is perpendicular to the thickness direction. The wiring circuit board 1 has a plate shape. The thickness of the wiring circuit board 1 is, for example, 10 μm or more. Alternatively, the thickness of the wiring circuit board 1 is, for example, 500 μm or less, preferably 300 μm or less, and more preferably 200 μm or less.

[0030] In Figure 1, the wiring circuit board 1 comprises 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 so as to cover the conductor layer 4.

[0031] The wiring circuit board 1 includes a plurality of divided sections 11A and 11B. Each of the divided sections 11A and 11B is arranged on one side of the metal support substrate 2 in the thickness direction. The divided sections 11A and 11B are divided in the planar direction. In the planar direction, divided section 11B is spaced apart from divided section 11A. Divided section 11A comprises a base insulating layer 3A, a conductor layer 4A, and a cover insulating layer 5A. Divided section 11B comprises a base insulating layer 3B, a conductor layer 4B, and a cover insulating layer 5B.

[0032] (2) Metal support substrate The metal support substrate 2 is positioned at the other end of the wiring circuit board 1 in the thickness direction. The metal support substrate 2 forms the other end surface of the wiring circuit board 1 in the thickness direction. The metal support substrate 2 extends in the plane direction. Both the one surface and the other surface of the metal support substrate 2 in the thickness direction are flat surfaces. The metal support substrate 2 is in contact with the other surface of the divided parts 11A and 11B in the thickness direction.

[0033] The metal support substrate 2 is made of, for example, a metal, preferably a metal rolled by a known method (hereinafter referred to as rolled metal).

[0034] Examples of metals include stainless steel and copper alloys. These can be used individually or in combination of two or more. Preferably, copper alloys are used as the metal. In other words, the metal support substrate 2 preferably contains a copper alloy, and more preferably consists of a copper alloy.

[0035] A copper alloy is an alloy containing copper. A copper alloy contains a primary metal consisting of copper and a secondary metal that can alloy with copper. "Alloyable" means that an alloy can be formed. The alloy may be a solid solution, a eutectic, an intermetallic compound, or a composite thereof.

[0036] In copper alloys, the second metal is an additive metal added to copper as the first metal. That is, the second metal is a metal other than copper. Examples of the second metal include titanium, nickel, and silicon. These can be used alone or in combination of two or more. That is, the copper alloy may be a two-component alloy or an alloy of three or more components. The second metal is preferably titanium. When the second metal is titanium, the copper alloy is a copper-titanium alloy. When a copper-titanium alloy is used, the wiring circuit board 1 has superior mechanical strength.

[0037] In copper alloys, the ratio of the primary metal (i.e., copper) to the secondary metal is set appropriately according to the purpose and application.

[0038] In copper alloys, the content ratio of the first metal (i.e., copper (hereinafter the same)) and the content ratio of the second metal (preferably titanium (hereinafter the same)) are set appropriately according to the purpose and application.

[0039] More specifically, the atomic proportion of the first metal is, for example, 50 to 99 atomic percent, preferably 80 to 99 atomic percent, and more preferably 90 to 99 atomic percent, relative to the total amount (total number of atoms) of the copper alloy.

[0040] Furthermore, the atomic proportion of the second metal is, for example, 1 to 50 atomic%, preferably 1 to 20 atomic%, and more preferably 1 to 10 atomic%, relative to the total amount (total number of atoms) of the copper alloy.

[0041] In copper alloys, the sum of the atomic proportions of the first metal and the second metal is, for example, 100 atomic percent.

[0042] Furthermore, on a mass basis, the mass percentage of the first metal is, for example, 50 to 99% by mass, preferably 80 to 99% by mass, and more preferably 90 to 99% by mass, relative to the total amount (total mass) of the copper alloy.

[0043] Furthermore, on a mass basis, the mass percentage of the second metal is, for example, 1 to 50% by mass, preferably 1 to 20% by mass, and more preferably 1 to 10% by mass, relative to the total amount (total mass) of the copper alloy.

[0044] In copper alloys, the sum of the mass percentages of the first metal and the second metal is, for example, 100% by mass.

[0045] In the metal support substrate 2, the copper alloy preferably has a phase separation structure. Examples of phase separation structures include a nanolamellar structure and a sea-island structure, with the sea-island structure being preferred. That is, the copper alloy more preferably has a sea-island structure.

[0046] A sea-island structure comprises a continuous sea area (i.e., a sea phase) and a discontinuous island area (i.e., an island phase). More specifically, a copper alloy having a sea-island structure comprises a sea area with a relatively high content of the first metal and a relatively low content of the second metal, and an island area with a relatively low content of the first metal and a relatively high content of the second metal. A copper alloy having a sea-island structure can be obtained, for example, by preheating (described later) a copper alloy having a nanolamellar structure.

[0047] Copper alloys have relatively high mechanical strength. The tensile strength of the above copper alloys is, for example, 800 MPa or more, preferably 900 MPa or more. The tensile strength of the above copper alloys is, for example, 2000 MPa or less, preferably 1700 MPa or less. That is, the tensile strength of copper alloys is, for example, 800 MPa or more and 2000 MPa or less, preferably 900 MPa or more and 1700 MPa or less. The tensile strength of copper alloys is measured in accordance with JIS Z 2241 (2011).

[0048] Furthermore, the above copper alloy has relatively high conductivity. For example, when the copper alloy is rolled, the conductivity of the copper alloy at 20°C is, for example, 30% IACS or less, preferably 20% IACS or less, and more preferably 15% IACS or less, in the rolling direction (MD direction). Also, the conductivity of the copper alloy at 20°C is, for example, 1% IACS or more, preferably 5% IACS or more, in the rolling direction (MD direction). That is, the conductivity of the copper alloy at 20°C 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, in the rolling direction (MD direction).

[0049] Furthermore, when a copper alloy is rolled, the conductivity of the copper alloy at 20°C is, for example, 30% IACS or less, preferably 20% IACS or less, and more preferably 15% IACS or less, in the direction perpendicular to the rolling direction (TD direction). Also, the conductivity of the copper alloy at 20°C is, for example, 1% IACS or more, preferably 5% IACS or more, in the direction perpendicular to the rolling direction (TD direction). That is, the conductivity of the copper alloy at 20°C 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, in the direction perpendicular to the rolling direction (TD direction).

[0050] IACS stands for International Annealed Copper Standard, and conductivity is measured in accordance with JIS H 0505 (1975) and JIS H 0500 (1998).

[0051] 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. Also, the thickness of the metal support substrate 2 is usually 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.

[0052] (3) Base insulating layer The base insulating layer 3 is arranged on one side of the metal support substrate 2 in the thickness direction. The base insulating layer 3 extends in the planar direction. One side of the base insulating layer 3 in the thickness direction is a flat surface. The base insulating layer 3 has a pattern shape. Specifically, the base insulating layer 3 includes a plurality of base insulating layers 3A, 3B. Each of the base insulating layers 3A, 3B is included in each of the divided parts 11A, 11B described above.

[0053] Examples of the base insulating layer 3 include resin (i.e., a cured resin). That is, the base insulating layer 3 preferably contains a resin, and more preferably consists of a resin. Examples of the resin include thermosetting resins, and more specifically, examples of polyimide resins, polyamide-imide resins, acrylic resins, polyethernitrile resins, polyethersulfone resins, polyethylene terephthalate resins, polyethylene naphthalate resins, and polyvinyl chloride resins, with polyimide resin being preferred. That is, the above resin is preferably a polyimide resin.

[0054] The base insulating layer 3 is formed, for example, by thermal curing the resin raw materials mentioned above. Details of the thermal curing of the resin raw materials will be described later.

[0055] The thickness of the base insulating layer 3 is, for example, 1 μm or more, preferably 3 μm or more. Alternatively, the thickness of the base insulating layer 3 is, for example, 30 μm or less, preferably 20 μm or less.

[0056] (4) Conductor layer The conductor layer 4 is arranged on one side of the base insulating layer 3 in the thickness direction. The conductor layer 4 extends in the plane direction. In this embodiment, the conductor layer 4 has a substantially rectangular shape in cross-section. One side of the conductor layer 4 in the thickness direction is a flat surface.

[0057] The conductor layer 4 includes a plurality of wirings and terminals. The wiring may be clock wiring, differential wiring, or other types of wiring. In this embodiment, the wiring is differential wiring. Differential wiring is a pair of wirings comprising a pair (i.e., two) signal lines. Each signal wiring is arranged substantially parallel to each other, forming a single signal transmission line. Terminals are formed at both ends in the longitudinal direction of each wiring. The wiring and terminals are arranged on one side of the base insulating layers 3A and 3B in the thickness direction.

[0058] Examples of materials for the conductive layer 4 include conductive metals, specifically copper. The terminal portion (not shown) may be plated using known methods as needed, and may also be heat-treated as needed. Details of the heat treatment will be described later.

[0059] (5) Cover insulating layer The cover insulating layer 5 is positioned on one side of the base insulating layer 3 in the thickness direction, covering the conductor layer 4. The cover insulating layer 5 forms one side of the wiring circuit board 1 in the thickness direction. The cover insulating layer 5 extends in the plane direction.

[0060] The cover insulating layer 5 has a pattern shape. Specifically, the cover insulating layer 5 includes a plurality of cover insulating layers 5A and 5B. Each of the cover insulating layers 5A and 5B is included in each of the divided parts 11A and 11B described above. Each of the cover insulating layers 5A and 5B has a conductor layer on one side of each of the base insulating layers 3A and 3B. 4 It is arranged to cover the wiring. In this embodiment, the end faces of the cover insulating layer 5 (cover insulating layers 5A and 5B, respectively) in the width direction are flush with the end faces of the base insulating layer 3 (base insulating layers 3A and 3B, respectively) in the width direction.

[0061] Examples of the cover insulating layer 5 include a resin similar to the resin exemplified as the base insulating layer 3 (i.e., a cured resin). That is, the cover insulating layer 5 preferably contains a resin, and more preferably consists of a resin. Examples of the resin include thermosetting resins, and more specifically, polyimide resins, polyamide-imide resins, acrylic resins, polyethernitrile resins, polyethersulfone resins, polyethylene terephthalate resins, polyethylene naphthalate resins, and polyvinyl chloride resins, with polyimide resin being preferred. That is, the above resin is preferably a polyimide resin.

[0062] The cover insulating layer 5 is formed, for example, by thermal curing the resin raw materials mentioned above. Details of the thermal curing of the resin raw materials will be described later.

[0063] The thickness of the cover insulating layer 5 is, for example, 1 μm or more, preferably 3 μm or more. Alternatively, the thickness of the cover insulating layer 5 is, for example, 30 μm or less, preferably 20 μm or less.

[0064] The thickness of the cover insulating layer 5 is the length in the thickness direction between one side of the base insulating layer 3 in the thickness direction and one side of the cover insulating layer 5 in the thickness direction that faces the aforementioned side without the conductor layer 4 in between.

[0065] The sum of the thickness of the cover insulating layer 5 and the thickness of 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 sum of the thickness of the cover insulating layer 5 and the thickness of the base insulating layer 3 is, for example, 5 μm or more.

[0066] 2. Manufacturing method of a wiring circuit board In the following, an embodiment of the method for manufacturing a wiring circuit board according to the present invention will be described with reference to Figure 2.

[0067] (1) Metal support substrate In the manufacturing of the wiring circuit board 1, first, the metal support substrate 2 is prepared as shown in Figures 2A and 2B.

[0068] More specifically, in this process, as shown in Figure 2A, first, an unpreheated (described later) metal support substrate 2 is prepared. Hereinafter, the unpreheated (described later) metal support substrate 2 will be referred to as the raw material 20. The raw material 20 is, for example, a commercially available product. The raw material 20 is, for example, a rolled copper alloy. Furthermore, the raw material 20 is, for example, made of a copper alloy having a nanolamellar structure.

[0069] Next, in this method, as shown in Figure 2B, the raw material 20 is preheated to obtain a preheated metal support substrate 2. Hereafter, the preheated metal support substrate 2 will be referred to as the heated substrate 21. Further details about preheating will be described later.

[0070] (2) Base insulating layer Next, in this method, as shown in Figure 2C, a base insulating layer 3 is formed on one side in the thickness direction of the substrate 21 to be heated.

[0071] The method for forming the base insulating layer 3 is not particularly limited, but for example, first, a varnish containing the raw materials of the resin is prepared. The varnish contains, for example, a photosensitive agent, the raw materials of the resin, and a solvent. The raw materials of the resin are compounds for obtaining the resin (i.e., the cured resin product) and are uncured resin components. The raw materials of the resin are appropriately selected depending on the type of resin. For example, if the resin is a polyimide resin, examples of raw materials of the resin include acidic dianhydrides and diamines.

[0072] More specifically, when the base insulating layer 3 is made of polyimide resin, the varnish contains a photosensitive agent, an acidic dianhydride and a diamine, and a solvent. The proportions of these components are set as appropriate depending on the purpose and application.

[0073] Next, in this method, the above-mentioned varnish is applied to one side of the metal support substrate 2 in the thickness direction and dried by heating to form 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., a precursor) of polyimide resin.

[0074] In the process of forming the base insulating layer 3, the drying temperature is, for example, 50°C to 200°C. The drying time is, for example, 1 minute to 60 minutes.

[0075] Next, in this method, the above-mentioned coating film is exposed to light and developed to form the coating film into a predetermined pattern. Next, in this method, the resin raw material is heat-cured to obtain the resin. More specifically, the coating film of the predetermined pattern (preferably polyamic acid resin as a raw material for polyimide resin) is heat-cured by heating to obtain the base insulating layer 3.

[0076] In the step of forming the base insulating layer 3, the thermosetting temperature is, for example, 100°C or higher, preferably 200°C or higher. Also, in the step of forming the base 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. The thermosetting time is, for example, 1 hour or more and 10 hours or less.

[0077] As a result, the base insulating layer 3 is positioned on one side in the thickness direction of the metal support substrate 2.

[0078] (3) Conductor layer Next, in this method, as shown in Figure 2D, a conductor layer 4 is formed on one side in the thickness direction of the base insulating layer 3.

[0079] The method for forming the conductor layer 4 is not particularly limited, and known conductor pattern formation methods can be employed. Examples of conductor pattern formation methods include additive methods, semi-additive methods, and subtractive methods, with additive methods being preferred.

[0080] Furthermore, although not shown in the diagram, in this method, the terminal portion of the conductor layer 4 may be plated, or the conductor layer 4 may be heat-treated, if necessary.

[0081] As a result, the conductor layer 4 is positioned on one side in the thickness direction of the base insulating layer 3.

[0082] (4) Cover insulating layer Next, in this method, as shown in Figure 2E, a cover insulating layer 5 is formed on one side in the thickness direction of the base insulating layer 3 and the conductor layer 4.

[0083] The method for forming the cover insulating layer 5 is not particularly limited, but for example, the cover insulating layer 5 may be formed in the same manner as the method for forming the base insulating layer 3 described above.

[0084] More specifically, for example, first, a varnish containing the raw materials of the resin is prepared. The varnish contains, for example, a photosensitive agent, the raw materials of the resin, and a solvent.

[0085] More specifically, when the cover insulating layer 5 is made of polyimide resin, the varnish contains a photosensitive agent, an acidic dianhydride and a diamine, and a solvent. The proportions of these components are set as appropriate depending on the purpose and application.

[0086] Next, in this method, the above-mentioned varnish is applied to one side in the thickness direction of the base insulating layer 3 and the conductive layer 4, and dried by heating to form 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., a precursor) of polyimide resin.

[0087] In the process of forming the cover insulating layer 5, the drying temperature is, for example, 50°C to 200°C. The drying time is, for example, 1 minute to 60 minutes.

[0088] Next, in this method, the above-mentioned coating film is exposed to light and developed to form the coating film into a predetermined pattern. Next, in this method, the resin raw material is heat-cured to obtain the resin. More specifically, the coating film of the predetermined pattern (preferably polyamic acid resin as a raw material for polyimide resin) is heat-cured by heating to obtain the cover insulating layer 5.

[0089] In the step of forming the cover insulating layer 5, the thermosetting temperature is, for example, 100°C or higher, preferably 200°C or higher. Also, in the step of forming the cover 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.

[0090] As described above, the cover insulating layer 5 is positioned on one side in the thickness direction of the base insulating layer 3 and the conductor layer 4. More specifically, on one side in the thickness direction of the base insulating layer 3, the cover insulating layer 5 covers the wiring of the conductor layer 4 and exposes the terminal portion (not shown).

[0091] Furthermore, in each of the above processes, the metal support substrate 2, the base insulating layer 3, the conductor layer 4, and the cover insulating layer 5 are aligned with each other to manufacture the wiring circuit board 1 (see Figure 1).

[0092] 3. Preheat In the manufacturing method of the wiring circuit board 1 described above, the metal support substrate 2 is heated. More specifically, in the above method, the varnish is heated and heat-cured during the formation of the base insulating layer 3. At this time, the metal support substrate 2 is heated together with the varnish. In addition, in the above method, the conductor layer 4 may be heat-treated as needed. At this time, the metal support substrate 2 is heated together with the conductor layer 4. In addition, in the above method, the varnish is heated and heat-cured during the formation of the cover insulating layer 5. At this time, the metal support substrate 2 is heated together with the varnish.

[0093] In such cases, the dimensions of the metal support substrate 2 may 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 cover insulating layer 5 decreases.

[0094] Therefore, in order to suppress changes in the dimensions (i.e., shrinkage) of the metal support substrate 2, in the manufacturing method of the wiring circuit board 1 described above, the metal support substrate 2 (i.e., the raw material 20) is preheated in the process of preparing the metal support substrate 2. Then, the base insulating layer 3, the conductor layer 4, and the cover insulating layer 5 are sequentially laminated onto the preheated metal support substrate 2 (i.e., the substrate to be heated 21).

[0095] More specifically, in the above method, in the step of preparing the metal support substrate 2, the raw material 20 is preheated to obtain the substrate to be heated 21 (preheating step).

[0096] The method for preheating the metal support substrate 2 is not particularly limited. For example, although not shown in the figure, the raw material 20 can be preheated by winding it onto a preheating core and then placing the raw material 20, wound onto the preheating core, in a heating furnace.

[0097] The preheating conditions are selected, for example, according to the heating temperature of the base insulating layer 3.

[0098] More specifically, as described above, the base insulating layer 3 is preferably made of resin, and the process of forming the base insulating layer 3 includes the process of obtaining resin by thermal curing the resin raw material. In such cases, a change in the dimensions of the metal support substrate 2 (i.e., shrinkage) may occur during the thermal curing of the resin raw material.

[0099] Therefore, in the manufacturing method of the wiring circuit board 1 described above, in order to suppress changes in the dimensions of the metal support substrate 2, the temperature of the raw material 20 during preheating is preferably adjusted to be higher than the temperature of the resin raw material during thermosetting.

[0100] More specifically, as described above, in the step of forming the base insulating layer 3, the thermosetting temperature is, for example, 100°C or higher, preferably 200°C or higher. Also, in the step of forming the base insulating layer 3, the thermosetting temperature is, as described above, 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.

[0101] Therefore, 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. Alternatively, the preheating temperature of the metal support substrate 2 may be 700°C or lower, preferably 600°C or lower. In other words, the preheating temperature may be 110°C or higher and 700°C or lower, preferably 120°C or higher and 600°C or lower.

[0102] 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. Also, 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. In other words, 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.

[0103] Furthermore, the preheating conditions are preferably selected in accordance with the heating temperature of the conductive layer 4.

[0104] More specifically, as described above, the conductive layer 4 may be heat-treated as needed. In such cases, a change in the dimensions (i.e., shrinkage) of the metal support substrate 2 may occur during the heat treatment of the conductive layer 4.

[0105] Therefore, 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, the temperature of the raw material 20 during preheating is preferably adjusted to be higher than the heat treatment temperature of the conductive layer 4.

[0106] Furthermore, the preheating conditions are preferably selected in accordance with the heating temperature of the cover insulating layer 5.

[0107] More specifically, as described above, the cover insulating layer 5 is preferably made of resin, and the step of forming the cover insulating layer 5 includes the step of obtaining resin by heat curing the resin raw material. In such a case, a change in the dimensions of the metal support substrate 2 (i.e., shrinkage) may occur when the resin raw material is heat cured.

[0108] Therefore, in the manufacturing method of the wiring circuit board 1 described above, in order to suppress changes in the dimensions of the metal support substrate 2, the temperature of the raw material 20 during preheating is preferably adjusted to be higher than the temperature of the resin raw material during thermosetting.

[0109] More specifically, as described above, in the step of forming the cover insulating layer 5, the thermosetting temperature is, for example, 100°C or higher, preferably 200°C or higher. Also, in the step of forming the cover 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.

[0110] In contrast, the preheating temperature of the metal support substrate 2 is higher than the thermosetting temperature in the process of forming the cover insulating layer 5, and as described above, for example, 110°C or higher, preferably 120°C or higher. Alternatively, 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.

[0111] Furthermore, the difference between the thermosetting temperature in the process of forming the cover 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. Also, the difference between the thermosetting temperature in the process of forming the cover 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. In other words, the difference between the thermosetting temperature in the process of forming the cover 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.

[0112] In addition, in this method, preferably, the metal support substrate 2 is preheated at a temperature higher than the highest heating temperature among the heating temperatures in each step in which the metal support substrate 2 is heated (excluding the preheating step).

[0113] In other words, the preheating temperature of the metal support substrate 2 is preferably higher than the maximum temperature of each step (except the preheating step) in the manufacturing of the wiring circuit board 1.

[0114] By preheating the metal support substrate 2 in this manner, it is possible to suppress changes in the dimensions of the metal support substrate 2 during each process in the manufacturing of the wiring circuit board 1 (except for the preheating process).

[0115] The preheating time for the metal support substrate 2 is not particularly limited, but can be, for example, between 10 minutes and 10 hours. 4. Effects According to the manufacturing method of the wiring circuit board 1 described above, 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 good accuracy.

[0116] More specifically, in the manufacturing method of the wiring circuit board 1 described above, the metal support substrate 2 is preheated in the step of preparing the metal support substrate 2 before the steps of forming the base insulating layer 3 and forming the conductor layer 4. That is, the dimensions of the metal support substrate 2 are changed in advance by heating. Therefore, by using such a metal support substrate 2, the steps of forming the base insulating layer 3 and forming the conductor layer 4 of During the forming process, changes in the dimensions of the metal support substrate 2 can be suppressed. As a result, the above-described method for manufacturing the wiring circuit board 1 allows for alignment with excellent precision.

[0117] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, the temperature during preheating of the metal support substrate 2 is higher than the temperature during the heat curing 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 allowing the base insulating layer 3 to be formed. of During the forming process, changes in the dimensions of the metal support substrate 2 can be suppressed. As a result, the above-described method for manufacturing the wiring circuit board 1 allows for alignment with excellent precision.

[0118] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, the polyimide resin is heated to a relatively high temperature, making it prone to changes in the dimensions of the metal support substrate 2. In contrast, in the above-described method for manufacturing the wiring circuit board 1, the temperature of the metal support substrate 2 during preheating is higher than the temperature of the polyimide resin during thermosetting. 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, the above-described method for manufacturing the wiring circuit board 1 allows for alignment with excellent precision.

[0119] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, the temperature during preheating of the metal support substrate 2 is higher than the temperature during the annealing process 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 conductive layer 4. As a result, the above-described method for manufacturing the wiring circuit board 1 allows for alignment with excellent precision.

[0120] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, if the metal support substrate 2 is made of a copper alloy, the dimensions of the metal support substrate 2 are prone to change. In contrast, in the above-described method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 are changed in advance by heating. Therefore, 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 process of forming the base insulating layer 3 and the process of forming the conductor layer 4. As a result, the above-described method for manufacturing the wiring circuit board allows for alignment with excellent precision.

[0121] Furthermore, in the above-described method for manufacturing a wiring circuit board, if the metal support substrate 2 is made of rolled metal, the dimensions of the metal support substrate 2 are prone to change. In contrast, in the above-described method for manufacturing a wiring circuit board 1, the dimensions of the metal support substrate 2 are changed in advance by heating. Therefore, 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 process of forming the base insulating layer 3 and the process of forming the conductor layer 4. As a result, the above-described method for manufacturing a wiring circuit board 1 allows for alignment with excellent precision.

[0122] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, the thickness of the metal support substrate 2 is less than or equal to a predetermined value. That is, the metal support substrate 2 is relatively thin. In such cases, the dimensions of the metal support substrate 2 are prone to change. In contrast, in the above-described method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 are changed in advance 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 process of forming the base insulating layer 3 and the process of forming the conductor layer 4. As a result, the above-described method for manufacturing the wiring circuit board 1 allows for alignment with excellent accuracy.

[0123] Furthermore, in the above-described method for manufacturing the wiring circuit board 1, by preheating the metal support substrate 2 while it is wound around the preheating core, the dimensions of the metal support substrate 2 can be more easily changed by preheating. Therefore, according to the above-described method for manufacturing the wiring circuit board 1, the steps of forming the base insulating layer 3 and the conductor layer 4 can be more easily completed. of During the forming process, changes in the dimensions of the metal support substrate 2 can be suppressed. As a result, the above-described method for manufacturing the wiring circuit board 1 allows for alignment with excellent precision.

[0124] 5. Variations In the modified examples, components and processes similar to those in the first embodiment are given the same reference numerals, and their detailed descriptions are omitted. Furthermore, the modified examples can achieve the same effects and advantages as the first embodiment, unless otherwise specified. Moreover, the first embodiment and its modified examples can be combined as appropriate.

[0125] For example, in the embodiment described above, the raw material 20 is wound onto a preheating core, and the raw material 20 wound onto the preheating core is placed in a heating furnace to heat-treat it. Alternatively, the raw material 20 can also be heat-treated by passing it through the heating furnace while being transported by a roll-to-roll method. The heat treatment conditions are the same as described above.

[0126] In the above-described method for manufacturing the wiring circuit board 1, the dimensions of the metal support substrate 2 can be more efficiently changed by preheating while conveying it using a roll-to-roll method. Therefore, according to the above-described method for manufacturing the wiring circuit board 1, changes in the dimensions of the metal support substrate 2 can be suppressed more efficiently during the process of forming the base insulating layer 3 and the process of forming the conductor layer 4. As a result, the above-described method for manufacturing the wiring circuit board 1 allows for alignment with excellent precision.

[0127] Although not described in detail here, in the above-mentioned wiring circuit board 1, the cover insulating layer 5 is an arbitrary layer, and may be omitted if necessary.

[0128] Furthermore, in the manufacturing method of the wiring circuit board 1 described above, the base insulating layer 3 is directly laminated to the metal support substrate 2. However, if necessary, the base insulating layer 3 may be indirectly laminated to the metal support substrate 2 via an adhesive layer (not shown). In other words, an adhesive layer (not shown) can be interposed between the metal support substrate 2 and the base insulating layer 3. The adhesive layer (not shown) is formed by applying an adhesive, described later, to the metal support substrate 2 in a known manner and curing it in a known manner.

[0129] Furthermore, in the manufacturing method of the wiring circuit board 1 described above, the conductor layer 4 is directly laminated to the base insulating layer 3. However, if necessary, the conductor layer 4 may be indirectly laminated to the base insulating layer 3 via an adhesive layer (not shown). In other words, an adhesive layer (not shown) can be interposed between the base insulating layer 3 and the conductor layer 4. The adhesive layer (not shown) is formed by applying an adhesive, described later, to the base insulating layer 3 in a known manner and curing it in a known manner.

[0130] Furthermore, in the manufacturing method of the wiring circuit board 1 described above, the cover insulating layer 5 is directly laminated to the conductor layer 4. However, if necessary, the cover insulating layer 5 may be indirectly laminated to the conductor layer 4 via an adhesive layer (not shown). In other words, an adhesive layer (not shown) can be interposed between the conductor layer 4 and the cover insulating layer 5. The adhesive layer (not shown) is formed by applying an adhesive, described later, to the base insulating layer 3 and the conductor layer 4 in a known manner and curing it in a known manner.

[0131] The adhesive layer described above is a cured product of a known adhesive. Examples of adhesives include epoxy adhesives. Epoxy adhesives contain, for example, an epoxy resin, a curing agent, and known additives.

[0132] The adhesive may be a room-temperature curing adhesive or a heat-curing adhesive. If the adhesive is a room-temperature curing adhesive, an adhesive layer (not shown) consisting of cured adhesive material can be formed by leaving the applied adhesive at room temperature. If the adhesive is a heat-curing adhesive, the adhesive layer (not shown) consisting of cured adhesive material can be formed by heating the applied adhesive.

[0133] If the adhesive is a heat-curing adhesive, the heating temperature of the adhesive is, for example, 100°C to 250°C. In such cases, preferably 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 to 200°C, preferably 20°C to 100°C. [Explanation of symbols]

[0134] 1 Wiring circuit board 2. Metal support substrate 3. Base insulating layer 4 Conductor layer 5. Cover insulation layer 11 Split body 20 Original fabric 21 Heated substrate

Claims

1. The process of preparing the metal support substrate, The process of forming a base insulating layer on one side in the thickness direction of the metal support substrate, A step of forming a conductive layer on one side of the thickness direction of the base insulating layer, A method for manufacturing a wiring circuit board, wherein the step of preparing the metal support substrate includes a step of preheating the metal support substrate.

2. The base insulating layer contains a resin, The step of forming the base insulating layer includes the step of obtaining the resin by thermal curing the raw material of the resin, A method for manufacturing a wiring circuit board according to claim 1, wherein the temperature during preheating of the metal support substrate is higher than the temperature during the thermal curing step in the process of forming the base insulating layer.

3. The method for manufacturing a wiring circuit board according to claim 2, wherein the resin is a polyimide resin.

4. Furthermore, the process includes forming a cover insulating layer on one side in the thickness direction of the base insulating layer and the conductor layer, The cover insulating layer contains resin, The step of forming the cover insulating layer includes the step of obtaining the resin by thermal curing the raw material of the resin, A method for manufacturing a wiring circuit board according to claim 1, wherein the temperature during preheating of the metal support substrate is higher than the temperature during the heat curing step in the process of forming the cover insulating layer.

5. The method for manufacturing a wiring circuit board according to claim 1, wherein the metal support substrate is made of a copper alloy.

6. The method for manufacturing a wiring circuit board according to claim 1, wherein the metal support substrate is made of rolled metal.

7. The method for manufacturing a wiring circuit board according to claim 1, wherein the thickness of the metal support substrate is 25 μm or more and 100 μm or less.

8. In the process of preparing the metal support substrate, The metal support substrate is wound onto the preheating core. The metal support substrate, which is wound around the preheating core, is preheated. A method for manufacturing a wiring circuit board according to claim 1.

9. In the process of preparing the metal support substrate, The metal support substrate is conveyed by a roll-to-roll method while preheating is performed. A method for manufacturing a wiring circuit board according to claim 1.

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