Wiring circuit board

Abstract

A wired circuit board (1) is provided with a metal support layer (2), a metal layer (3), a first insulating layer (4), and a conductor pattern (5). The conductor pattern (5) has a first surface (S11) that is in contact with one surface (S3) of the first insulating layer (4), and a second surface (S12) that is disposed on the opposite side of the first insulating layer (4) with respect to the first surface (S11). The brightness of one surface (S3) of the metal layer (3) is 89.0 or less, and the brightness of the second surface (S12) of the conductor pattern (5) is 155.0 or more.

Description

Technical Field

[0001] This invention relates to wiring circuit boards. Background Technology

[0002] Previously, a wiring circuit board was known to have an insulating layer, a conductor layer disposed on one side of the insulating layer, a metal support disposed on the other side of the insulating layer, and a metal thin film disposed between the insulating layer and the metal support (for example, see Patent Document 1 below).

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2024-8277 Summary of the Invention

[0004] The problem that the invention aims to solve In a wiring circuit board as described in Patent Document 1, when it is desired to inspect the shape of a conductor layer based on image recognition, the accuracy of reading the shape of the conductor layer may be reduced due to reflected light from the metal thin film.

[0005] The present invention provides a wiring circuit board that can improve the reading accuracy of the shape of conductor patterns based on image recognition.

[0006] Technical solutions for solving the problem The present invention [1] includes a wiring circuit board comprising: a metal support layer; a metal layer disposed on one side surface of the metal support layer in the thickness direction; an insulating layer disposed on one side surface of the metal layer in the thickness direction; and a conductor pattern disposed on one side surface of the insulating layer in the thickness direction, having a first surface in contact with the one side surface of the insulating layer and a second surface disposed on the opposite side of the insulating layer relative to the first surface in the thickness direction, wherein the brightness of the one side surface of the metal layer in the thickness direction is... The brightness of the second surface of the conductor pattern is 155.0 or higher, and the brightness is below 89.0.

[0007] Based on this structure, the brightness of one side surface of the metal layer... The brightness is below 89.0, and the brightness of the second side of the conductor pattern is above 155.0.

[0008] Therefore, in image recognition, it is possible to ensure the contrast between the metal layer and the conductor pattern.

[0009] As a result, it is possible to improve the accuracy of reading the shape of conductor patterns based on image recognition.

[0010] The present invention [2] includes the wiring circuit board of [1] above, wherein the arithmetic mean roughness Ra of the second surface of the conductor pattern is 6.4 nm or less.

[0011] This structure can suppress the scattering of illumination light from the inspection system on the second surface.

[0012] As a result, in image recognition, the contrast between the metal layer and the conductor pattern can be further ensured.

[0013] The present invention [3] includes the wiring circuit board of [1] or [2] above, wherein the conductor pattern has a conductor layer and a cladding metal layer covering the conductor layer, the cladding metal layer having a second side.

[0014] The present invention [4] includes the wiring circuit board of the above [3], wherein the cladding metal layer is a nickel plating layer.

[0015] The present invention [5] includes the wiring circuit substrate of [4] above, wherein the thickness of the cladding metal layer is 45.0 nm or more.

[0016] The present invention [6] includes the wiring circuit board of any one of [1] to [5] above, wherein the metal layer is made of copper.

[0017] The present invention [7] includes the wiring circuit board of any one of [1] to [6] above, wherein the thickness of the insulating layer is less than 50 μm.

[0018] Invention Effects According to the wiring circuit board of the present invention, it is possible to improve the reading accuracy of the shape of the conductor pattern based on image recognition. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of one embodiment of the wiring circuit board of the present invention.

[0020] Figure 2A as well as Figure 2B yes Figure 1 The manufacturing process of the wiring circuit board shown is as follows: Figure 2A Indicates the metal layer formation process. Figure 2B This indicates the process of forming the first insulating layer.

[0021] Figures 3A-3C then Figure 2B , indicating the conductor pattern formation process. Figure 3A This indicates the process of forming a protective metal layer for the conductor pattern. Figure 3B This refers to the process of forming a conductor layer with a conductor pattern. Figure 3C This refers to the process of forming a cladding metal layer that creates a conductor pattern.

[0022] Figure 4 This is a flowchart of the inspection process.

[0023] Figure 5 yes Figure 4 The diagram illustrates the "process of obtaining an image of a conductor pattern" in the inspection procedure shown. Detailed Implementation

[0024] 1. Wiring circuit board like Figure 1 As shown, the wiring circuit board 1 includes a metal support layer 2, a metal layer 3, a first insulating layer 4 as an example of an insulating layer, a conductor pattern 5, and a second insulating layer 6.

[0025] (1) Metal support layer The metal support layer 2 supports the metal layer 3, the first insulating layer 4, the conductor pattern 5, and the second insulating layer 6. The entire metal support layer 2 overlaps with the first insulating layer 4 in the thickness direction. The metal support layer 2 is made of a metal different from that of the metal layer 3 and the conductor pattern 5. Examples of materials for the metal support layer 2 include stainless steel and copper alloys. The metal support layer 2 is preferably made of a copper alloy.

[0026] (2) Metal layer Metal layer 3 is disposed on one side of metal support layer 2 in the thickness direction. Metal layer 3 is disposed on one side surface S1 of metal support layer 2 in the thickness direction. Metal layer 3 is disposed between metal support layer 2 and first insulating layer 4 in the thickness direction.

[0027] Brightness of surface S2 on one side of metal layer 3 in the thickness direction (JIS Z 8781-4) is 89.0 or less, preferably 82.0 or less, more preferably 81.0 or less, and even more preferably 80.0 or less. If the brightness of the surface S2 on one side of the metal layer 3 in the thickness direction... If the value is below the aforementioned upper limit, it is easy to ensure the contrast between the metal layer 3 and the conductor pattern 5.

[0028] Brightness of surface S2 on one side of metal layer 3 in the thickness direction For example, a value of 51.0 or higher. The brightness of the surface S2 on one side of the metal layer 3 in the thickness direction. It can be 65.0 or above, or 70.0 or above.

[0029] Metal layer 3 may also have a conductor layer 31 and a protective metal layer 32. Metal layer 3 may also be composed only of the conductor layer 31 and lack the protective metal layer 32. When metal layer 3 is composed only of the conductor layer 31 and lacks the protective metal layer 32, the brightness of one surface S2 of metal layer 3 in the thickness direction... For example, it can be higher than 82.0 or higher than 85.0.

[0030] A conductor layer 31 is disposed on one side surface S1 of the metal support layer 2 in the thickness direction. The conductor layer 31 is disposed between the metal support layer 2 and the protective metal layer 32 in the thickness direction. The conductor layer 31 is made of metal. Examples of metals include copper, silver, gold, iron, aluminum, chromium, and their alloys. The conductor layer 31 is preferably made of copper. In the case where the metal layer 3 does not have a protective metal layer 32 and is only composed of the conductor layer 31, the metal layer 3 is preferably made of copper. The conductor layer 31 is, for example, a plating.

[0031] The thickness of the conductor layer 31 is, for example, 1.0 μm to 15.0 μm, preferably 1.5 μm to 10.0 μm.

[0032] A protective metal layer 32 is disposed on one side surface of the conductor layer 31 in the thickness direction. The protective metal layer 32 covers the conductor layer 31. The protective metal layer 32 is disposed between the conductor layer 31 and the first insulating layer 4. The protective metal layer 32 protects the conductor layer 31. Examples of materials for the protective metal layer 32 include chromium, nickel, titanium, and alloys thereof. The protective metal layer 32 preferably contains chromium. The protective metal layer 32 may be, for example, a sputtered layer.

[0033] The thickness of the protective metal layer 32 is, for example, 30 nm to 100 nm, preferably 50 nm to 80 nm.

[0034] (4) First insulating layer The first insulating layer 4 is disposed on one side of the metal layer 3 in the thickness direction. The first insulating layer 4 is disposed on one side surface S2 of the metal layer 3 in the thickness direction. The first insulating layer 4 is disposed between the metal layer 3 and the conductor pattern 5 in the thickness direction. The first insulating layer 4 insulates the metal layer 3 relative to the conductor pattern 5. The first insulating layer 4 is made of resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester. The first insulating layer 4 is preferably made of polyimide.

[0035] The thickness of the first insulating layer 4 is, for example, 50 μm or less, preferably 20 μm or less. When the thickness of the first insulating layer 4 is below the aforementioned upper limit, the illumination light of the inspection system is incident from one side of the first insulating layer 4, passes through the first insulating layer 4, and reaches one side surface S2 of the metal layer 3. The illumination light reaching one side surface S2 of the metal layer 3 is reflected at one side surface S2 of the metal layer 3. Here, if the thickness of the first insulating layer 4 is below the aforementioned upper limit, the illumination light (incident light) incident on the first insulating layer 4 and the light reflected at one side surface S2 of the metal layer 3 (reflected light) are difficult to absorb and diffuse within the first insulating layer 4. Therefore, the reflected light from one side surface S2 of the metal layer 3 remains almost unabsorbed or undiffused within the first insulating layer 4 and easily reaches the inspection system. Therefore, it is difficult to ensure the contrast between the metal layer 3 and the conductor pattern 5.

[0036] The lower limit of the thickness of the first insulating layer 4 is not limited as long as the metal layer 3 can be insulated relative to the conductor pattern 5. The thickness of the first insulating layer 4 is, for example, 5 μm or more.

[0037] (5) Conductor pattern The conductor pattern 5 is disposed on one side of the first insulating layer 4 in the thickness direction. The conductor pattern 5 is also disposed on one side surface S3 of the first insulating layer 4 in the thickness direction. The conductor pattern 5 is disposed on the opposite side of the metal layer 3 in the thickness direction relative to the first insulating layer 4. The conductor pattern 5 has a first surface S11 and a second surface S12. The first surface S11 is the other side surface of the conductor pattern 5 in the thickness direction. The first surface S11 is in contact with one side surface S3 of the first insulating layer 4. The second surface S12 is one side surface of the conductor pattern 5 in the thickness direction. The second surface S12 is disposed on the opposite side of the first insulating layer 4 in the thickness direction relative to the first surface S11.

[0038] The brightness of the second surface S12 of the conductor pattern 5 is 155.0 or higher, preferably 157.0 or higher. If the brightness of one side surface S1 of the metal layer 3... If the brightness of the second surface S12 of the conductor pattern 5 is 89.0 or less, and the brightness of the second surface S12 of the conductor pattern 5 is 155.0 or more, then even if the thickness of the first insulating layer 4 is less than or equal to the aforementioned upper limit value, the contrast between the metal layer 3 and the conductor pattern 5 can be ensured. For example, the brightness of the second surface S12 of the conductor pattern 5 is 200.0 or less.

[0039] The brightness of the second surface S12 of the conductor pattern 5 was measured by the method described in the embodiments described later.

[0040] The arithmetic mean roughness Ra of the second surface S12 of the conductor pattern 5 is, for example, 6.4 nm or less, preferably 5.9 nm or less. If the arithmetic mean roughness Ra of the second surface S12 of the conductor pattern 5 is below the aforementioned upper limit, scattering of illumination light from the inspection system on the second surface S12 can be suppressed. As a result, in image recognition, the contrast between the metal layer and the conductor pattern can be further ensured. The arithmetic mean roughness Ra of the second surface S12 of the conductor pattern 5 is, for example, 5.0 nm or more.

[0041] The conductor pattern 5 may also have a protective metal layer 51, a conductor layer 52, and a covering metal layer 53.

[0042] A protective metal layer 51 is disposed on one side surface S3 of the first insulating layer 4 in the thickness direction. The protective metal layer 51 is disposed between the first insulating layer 4 and the conductor layer 52. The protective metal layer 51 protects the conductor layer 52. Examples of materials for the protective metal layer 51 include chromium, nickel, titanium, and alloys thereof. The protective metal layer 51 is preferably made of chromium. The protective metal layer 51 may be, for example, a sputtered layer.

[0043] The thickness of the protective metal layer 51 is, for example, 30 nm to 100 nm, preferably 50 nm to 80 nm.

[0044] A conductor layer 52 is disposed on one side surface of the protective metal layer 51 in the thickness direction. The conductor layer 52 is made of metal. Examples of metals include copper, silver, gold, iron, aluminum, chromium, and their alloys. The conductor layer 52 is preferably made of copper.

[0045] The thickness of the conductor layer 52 is, for example, 10 μm to 60 μm.

[0046] A cladding metal layer 53 covers the conductor layer 52. Specifically, the cladding metal layer 53 covers one surface of the conductor layer 52 in the thickness direction and the side surface of the conductor layer 52. The cladding metal layer 53 protects the conductor layer 52. The cladding metal layer 53 is disposed between the conductor layer 52 and the second insulating layer 6. The cladding metal layer 53 has a second surface S12 of the conductor pattern 5. Examples of materials for the cladding metal layer 53 include nickel, tin, silver, palladium, and alloys thereof. Nickel is preferably a preferred material for the cladding metal layer 53. The cladding metal layer 53 is preferably a nickel-plated layer.

[0047] The thickness of the cladding metal layer 53 is, for example, 45.0 nm or more, preferably 50.0 nm or more. If the thickness of the cladding metal layer 53 is at or above the aforementioned upper limit, the brightness of the cladding metal layer 53 can be ensured. The thickness of the cladding metal layer 53 is not limited as long as it can protect the conductor layer 52. For example, the thickness of the cladding metal layer 53 can be 100.0 nm or less, or 80.0 nm or less.

[0048] (6) Second insulating layer The second insulating layer 6 is disposed on one side of the first insulating layer 4 in the thickness direction. The second insulating layer 6 is also disposed on one surface of the first insulating layer 4 in the thickness direction. The second insulating layer 6 is made of resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester. The second insulating layer 6 is preferably made of polyimide. The second insulating layer 6 covers the conductor pattern 5.

[0049] The thickness of the second insulating layer 6 is, for example, 1 μm to 50 μm, preferably 4 μm to 20 μm.

[0050] 2. Manufacturing method of wiring circuit board The manufacturing method of the wiring circuit board 1 includes a metal layer formation process (see reference). Figure 2A ), the first insulating layer formation process (refer to Figure 2B Conductor pattern formation process (refer to) Figures 3A-3C ), the second insulating layer formation process (refer to) Figure 1 ), and inspection procedures (refer to Figure 4 ).

[0051] (1) Metal layer formation process like Figure 2A As shown, in the conductor layer formation process, a metal layer 3 is formed on one side surface S1 of the metal support layer 2.

[0052] In order to form the metal layer 3, firstly, for example, a conductor layer 31 is formed on one side surface S1 of the metal support layer 2 by electroplating.

[0053] Next, a protective metal layer 32 is formed on the conductor layer 31, for example, by sputtering. Through the above steps, the metal layer 3 is formed.

[0054] (2) First insulating layer formation process Next, as Figure 2B As shown, in the first insulating layer forming process, a first insulating layer 4 is formed on one side surface S2 of the metal layer 3.

[0055] In detail, in the first insulating layer formation process, firstly, a solution of photosensitive resin (varnish) is applied to the metal layer 3 and allowed to dry. This forms a photosensitive resin coating on the metal layer 3.

[0056] Next, the photosensitive resin coating is exposed to light, and then the exposed coating is developed. Through these steps, the first insulating layer 4 is formed.

[0057] (3) Conductor pattern formation process Next, in the conductor pattern forming process, a conductor pattern 5 is formed on one side surface S3 in the thickness direction of the first insulating layer 4.

[0058] In detail, firstly, such as Figure 3A As shown, a protective metal layer 51 is formed, for example, by sputtering, on one side surface S3 in the thickness direction of the first insulating layer 4.

[0059] Next, as Figure 3B As shown, a conductor layer 52 is formed, for example, by electrolytic plating, on one side surface of the protective metal layer 51 in the thickness direction.

[0060] In order to form the conductor layer 52, the protective metal layer 51 is first coated with an anti-plating agent R.

[0061] Next, the resist R is exposed, and then the exposed resist R is developed. Thus, the resist R in the portion forming the conductor layer 52 is removed, and the protective metal layer 51 is exposed in the portion where the conductor layer 52 is formed. On the other hand, the resist R remains in the portion where the conductor layer 52 is not formed.

[0062] Next, a conductor layer 52 is formed on the exposed protective metal layer 51 by electroplating. After the electroplating is completed, the resist R is stripped off, and the protective metal layer 51 exposed due to the stripping of the resist R is removed by etching.

[0063] Next, as Figure 3C As shown, a cladding metal layer 53 is formed on the surface of the conductor layer 52, for example, by electroless plating.

[0064] Through the above steps, conductor pattern 5 is formed.

[0065] (4) Second insulation layer formation process Next, as Figure 1 As shown, in the second insulating layer forming process, a second insulating layer 6 is formed on one side surface S3 in the thickness direction of the first insulating layer 4.

[0066] In detail, in the second insulating layer forming process, firstly, a solution of photosensitive resin (varnish) is applied to the first insulating layer 4 and the conductor pattern 5 and then dried to form a photosensitive resin coating.

[0067] Next, the photosensitive resin coating is exposed to light, and then the exposed coating is developed. This forms the second insulating layer 6.

[0068] (5) Inspection process Next, in the inspection process, an inspection system (specifically, the inspection system described in the embodiments described later) is used to inspect the shape of the conductor pattern 5 by image recognition.

[0069] In detail, during the inspection process, such as Figure 4 As shown, firstly, an image of the wiring circuit board 1 is acquired (S21). To acquire an image of the conductor pattern 5, as shown... Figure 5 As shown, the surface of one side of the wiring circuit board 1 is illuminated by the illumination 10 of the inspection system (more specifically, the incident LED of the inspection microscope described in the embodiments described later) and photographed.

[0070] At this time, the brightness of one side surface S2 of metal layer 3 The brightness is 89.0 or less, and the brightness of the second surface S12 of the conductor pattern 5 is 155.0 or more. Therefore, the contrast between the metal layer 3 and the conductor pattern 5 can be ensured.

[0071] The inspection system uses the given brightness as a threshold to generate the contour model of conductor pattern 5.

[0072] Next, as Figure 4 As shown, the inspection system compares the contour model of the generated conductor pattern 5 with the shape of the conductor pattern 5 in the CAM data to detect defective parts (S22).

[0073] At this point, by ensuring the contrast between the metal layer 3 and the conductor pattern 5, the reduction in the accuracy of the generated contour model can be suppressed. Therefore, the increase in false detections of defective areas (misdetecting areas without defects as defective areas) can be suppressed. That is, the accuracy of reading the shape of the conductor pattern 5 based on image recognition can be improved.

[0074] Next, the operator determines whether the defective parts detected by the inspection system are good or bad (S23).

[0075] At this point, because the increase in false detections of defective parts is suppressed, the operator can efficiently perform the good or bad judgment.

[0076] 3. Effects (1) Based on the brightness of surface S2 of one side of the metal layer 3 on the wiring circuit board 1. The brightness is 89.0 or less, and the brightness of the second surface S12 of conductor pattern 5 is 155.0 or more.

[0077] Therefore, in image recognition, the contrast between the metal layer 3 and the conductor pattern 5 can be ensured.

[0078] As a result, it is possible to improve the reading accuracy of the shape of the conductor pattern 5 based on image recognition.

[0079] (2) According to the wiring circuit substrate 1, the arithmetic mean roughness Ra of the second surface S12 of the conductor pattern 5 is less than 6.4 nm.

[0080] Therefore, it is possible to suppress the scattering of the illumination light from the inspection system on the second surface S12.

[0081] As a result, in image recognition, the contrast between the metal layer 3 and the conductor pattern 5 can be further ensured.

[0082] Example The following examples and comparative examples further illustrate the present invention. It should be noted that the present invention is not limited to any particular example or comparative example. Furthermore, the specific numerical values ​​of proportions (including proportions), property values, parameters, etc., used in the following description can replace the corresponding upper limits (defined as "below" or "less than") or lower limits (defined as "above" or "exceeding") of the proportions (including proportions), property values, parameters, etc., recorded in the "Specific Embodiments" above.

[0083] 1. Manufacturing of wiring circuit boards First, a conductor layer made of copper is formed by electroplating one side of a metal support layer made of copper alloy.

[0084] Next, a protective metal layer composed of chromium is formed on the conductor layer by sputtering. Through the above steps, a metal layer composed of the conductor layer and the protective metal layer is formed on one side surface of the metal support layer (metal layer formation process).

[0085] The lightness of one side of the metal layer was measured using a colorimeter (CR-10 Plus, manufactured by Konica Minolta). The results are shown in Table 1.

[0086] Next, a solution of photosensitive polyimide (varnish) is applied to one side of the metal layer and allowed to dry. Thus, a photosensitive polyimide coating is formed on one side of the metal layer.

[0087] Next, the photosensitive polyimide coating was exposed, and then the exposed coating was developed. As a result, a first insulating layer made of polyimide was formed on one side surface of the metal layer (first insulating layer formation process).

[0088] Next, a protective metal layer made of chromium was formed on the first insulating layer by sputtering.

[0089] Next, a resist was applied to the first insulating layer, and the resist was exposed and developed. As a result, the resist on the portion of the conductor layer forming the conductor pattern was removed, exposing the protective metal layer on that portion of the conductor layer.

[0090] Next, a copper conductor layer was formed on top of the exposed protective metal layer through electroplating. The surface roughness (arithmetic mean roughness Ra) of one side of the conductor layer was measured using atomic force microscopy. The results are shown in Table 1. It should be noted that the surface roughness (arithmetic mean roughness Ra) can also be measured using laser microscopy.

[0091] After electroplating is completed, the resist is stripped, and the protective metal layer exposed due to the stripping of the resist is removed by etching.

[0092] Next, a nickel-based cladding metal layer was formed on the surface of the conductor layer by electroless plating. The thickness of the cladding metal layer is shown in Table 1.

[0093] Thus, a conductor pattern is formed on the first insulating layer (conductor pattern forming process).

[0094] Next, a solution of photosensitive polyimide (varnish) is applied over the first insulating layer and the conductor pattern and allowed to dry, forming a photosensitive polyimide coating.

[0095] Next, the photosensitive polyimide coating was exposed, and then the exposed coating was developed. Thus, a second insulating layer was formed on the first insulating layer (second insulating layer formation process).

[0096] Through the above steps, the wiring circuit board was obtained.

[0097] 2. Evaluation (1) Detection of defective parts Defects in the conductor patterns of the wiring circuit boards of each embodiment and comparative example were detected using an image inspection system.

[0098] In detail, the image inspection system includes an inspection microscope (MX63L, manufactured by EVIDENT) and a digital camera for the microscope (DP22, manufactured by EVIDENT). The image inspection system uses the digital camera for the microscope to capture images of the wiring circuit board magnified by the inspection microscope, and uses image analysis software (Stream Basic, manufactured by OLYMPUS) to detect defects.

[0099] It should be noted that the shooting conditions can be controlled by image analysis software. The shooting conditions are shown below.

[0100] <Conditions for digital cameras used with microscopes> Exposure; 40ms Sensitivity; ISO 200 Contrast ratio: 0.00 Sharpness; 1 White balance; R: 1.6, B: 2 <Checking the Microscope Conditions> Mirror unit; BF Radiated LED brightness: 47 Aperture stop; 50% Table 1 shows the brightness of the conductor pattern in the images captured under the above shooting conditions, as well as the number of images (detection count) detected as defective areas by the inspection system.

[0101] (2) Method for determining the surface roughness of the metal coating After inspecting the defective areas, the second insulating layer of the wiring circuit board of each embodiment and comparative example was peeled off, and the surface roughness (arithmetic mean roughness Ra) of one side surface (second side) of the cladding metal layer of the conductor pattern exposed due to the peeling of the second insulating layer was measured using an atomic force microscope. The results are shown in Table 1.

[0102] [Table 1]

[0103] 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.

[0104] Industrial availability The wiring circuit board of the present invention can be used for the connection of electronic components.

[0105] Symbol Explanation 1: Wiring circuit board 2: Metal support layer 3: Metal layer 31: Conductor layer 32: Protective metal layer 4: First insulating layer (an example of an insulating layer) 5: Conductor pattern 51: Protective metal layer 52: Conductor layer 53: Coated metal layer 6: Second insulation layer S1: One side surface of the metal support layer S2: One side surface of the metal layer S3: One side surface of the first insulating layer S11: First surface of the conductor pattern S12: The second side of the conductor pattern.

Claims

1. A wiring circuit board, comprising: Metal support layer; A metal layer disposed on one side surface of the metal support layer in the thickness direction; An insulating layer disposed on one side surface of the metal layer in the thickness direction; as well as A conductor pattern is disposed on one side surface of the insulating layer in the thickness direction, and has a first surface in contact with the one side surface of the insulating layer, and a second surface disposed on the opposite side of the insulating layer in the thickness direction relative to the first surface. The brightness of the metal layer on one side surface in the thickness direction Below 89.0 The brightness of the second surface of the conductor pattern is 155.0 or higher.

2. The wiring circuit board according to claim 1, wherein, The arithmetic mean roughness Ra of the second surface of the conductor pattern is less than 6.4 nm.

3. The wiring circuit board according to claim 1, wherein, The conductor pattern includes a conductor layer and a cladding metal layer covering the conductor layer. The cladding metal layer has the second side.

4. The wiring circuit board according to claim 3, wherein, The cladding metal layer is a nickel-plated layer.

5. The wiring circuit board according to claim 4, wherein, The thickness of the cladding metal layer is 45.0 nm or more.

6. The wiring circuit board according to claim 1, wherein, The metal layer is made of copper.

7. The wiring circuit board according to claim 1, wherein, The thickness of the insulating layer is less than 50 μm.

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