Wired circuit board and method for producing wired circuit board

Abstract

To provide a wiring circuit board capable of improving reading accuracy of a shape of a conductor pattern by image recognition, and to provide a method of manufacturing the wiring circuit board.SOLUTION: The wired circuit board 1 includes a metal supporting layer 2, a conductive layer 3, a first insulating layer 4, and a conductive pattern 5. The conductive layer 3 and the conductive pattern 5 are made of a copper plating layer, and the metal supporting layer 2 is made of a metal different from that of the conductive layer 3 and the conductive pattern 5. The lightness L * of the second surface S12 of the conductive layer 3 is equal to or more than the lightness L * of the one side surface S1 of the metallic support layer and the difference from the lightness L * of the one side surface S1 is 7.0 or less, or is less than the lightness L * of the one side surface S1 and the difference from the lightness L * of the one side surface S1 is 24.0 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wired circuit board and a method for manufacturing the wired circuit board. [Background technology]

[0002] Conventionally, a wired circuit board has been known that includes an insulating layer, a conductor layer disposed on one surface 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 (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-8277 Summary of the Invention [Problem to be solved by the invention]

[0004] In a wired circuit board such as that described in Patent Document 1, when inspecting the shape of the conductor layer by image recognition, the accuracy of reading the shape of the conductor layer may be reduced due to reflected light from the thin metal film.

[0005] The present invention provides a wired circuit board that can improve the accuracy of reading the shape of a conductor pattern by image recognition, and a method for manufacturing the wired circuit board. [Means for solving the problem]

[0006] The present invention [1] is a lightness L * a metal support layer having a first lightness, a first surface disposed on the one surface of the metal support layer in the thickness direction and in contact with the one surface of the metal support layer, and a second surface disposed on the opposite side of the metal support layer with respect to the first surface, *a conductor layer having a second brightness, an insulating layer disposed on the second surface of the conductor layer in the thickness direction, and a conductor pattern disposed on the opposite side of the conductor layer with respect to the insulating layer in the thickness direction, wherein the conductor layer and the conductor pattern are made of a copper plated layer, the metal support layer is made of a metal different from that of the conductor layer and the conductor pattern, and the second brightness is equal to or greater than the first brightness and has a difference of 7.0 or less from the first brightness, or is less than the first brightness and has a difference of 24.0 or less from the first brightness.

[0007] According to this configuration, the lightness L of the second surface of the conductor layer * (Second brightness) is the brightness L of one surface of the metal support layer * The brightness is equal to or greater than the first brightness and the difference from the first brightness is 7.0 or less, or the brightness is less than the first brightness and the difference from the first brightness is 24.0 or less.

[0008] Therefore, the lightness L of the second surface of the conductor layer * The lightness L of one surface of the metal support layer * can be approached.

[0009] This reduces the luminosity of the conductor pattern L * and the lightness L of the second surface of the conductor layer * The difference can be secured.

[0010] As a result, the accuracy of reading the shape of the conductor pattern by image recognition can be improved.

[0011] The present invention [2] includes the wired circuit board according to the above [1], wherein the metal support layer is made of a copper alloy.

[0012] The present invention [3] includes the wired circuit board according to the above [1] or [2], wherein the insulating layer is made of polyimide and has a thickness of 50 μm or less.

[0013] The present invention [4] is a method for determining the chromaticity of the second surface a *The present invention includes the wired circuit board of any one of the above [1] to [3], wherein the value of the resistance is 22.0 or more.

[0014] The present invention [5] is a method for determining the chromaticity b of the second surface. * The present invention includes the wired circuit board of any one of the above [1] to [4], wherein the value of the resistance is 17.0 or more.

[0015] The present invention [6] is a method for manufacturing a wired circuit board according to any one of the above [1] to [5], comprising a conductor layer forming step of forming the conductor layer on the one surface of the metal support layer, a roughening step of roughening the second surface of the conductor layer to reduce the second brightness, an insulating layer forming step of forming the insulating layer on the second surface of the conductor layer, and a conductor pattern forming step of forming the conductor pattern on the insulating layer.

[0016] According to this method, the lightness L of the second surface of the conductor layer is increased by the roughening step. * By lowering the lightness L of one surface of the metal support layer, * can be approached.

[0017] This reduces the luminosity of the conductor pattern L * and the lightness L of the second surface of the conductor layer * The difference can be secured.

[0018] As a result, the accuracy of reading the shape of the conductor pattern by image recognition can be improved.

[0019] The present invention [7] includes the method for producing a wired circuit board according to the above [6], wherein the second surface of the conductor layer is roughened by etching in the roughening step.

[0020] The present invention [8] includes the method for manufacturing a wired circuit board according to the above [6] or [7], further comprising an inspection step of inspecting the shape of the conductor pattern by image recognition. [Effects of the Invention]

[0021] According to the wired circuit board and the method for manufacturing the wired circuit board of the present invention, it is possible to improve the accuracy of reading the shape of the conductor pattern by image recognition. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a cross-sectional view of one embodiment of the wired circuit board of the present invention. [Figure 2] 2A to 2D show the manufacturing process of the wired circuit board shown in FIG. 1, where FIG. 2A shows the conductor layer forming process, FIG. 2B shows the roughening process, FIG. 2C shows the first insulating layer forming process, and FIG. 2D shows the conductor pattern forming process. [Figure 3] Figure 3 shows the inspection process. [Figure 4] FIG. 4 shows an image of the surface of the metal support layer made of a copper alloy in Example 1, taken with a CCD camera. [Figure 5] FIG. 5 shows an image of the surface of the conductor layer before the roughening step in Example 1, taken with a CCD camera. [Figure 6] FIG. 6 shows an image of the surface of the conductor layer after the roughening step in Example 1, taken with a CCD camera. [Figure 7] Fig. 7A shows an image taken with a CCD camera of the conductor pattern of the wired circuit board obtained in Example 1. Fig. 7B shows an image taken with a CCD camera of the conductor pattern of the wired circuit board obtained in Comparative Example. DETAILED DESCRIPTION OF THE INVENTION

[0023] 1. Wiring circuit board As shown in FIG. 1, the wired circuit board 1 includes a metal support layer 2, a conductor layer 3, a first insulating layer 4 as an example of an insulating layer, a conductor pattern 5, and a second insulating layer 6.

[0024] (1) Metal support layer The metal support layer 2 supports the conductor 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 the conductor 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.

[0025] Lightness L of one surface S1 of the metal support layer 2 in the thickness direction of the metal support layer 2 * (JIS Z 8781-4) is the first lightness.

[0026] When the metal support layer 2 is made of a copper alloy, the first brightness is, for example, 74.9.

[0027] (2) Conductor layer The conductor layer 3 is disposed on one side of the metal support layer 2 in the thickness direction. The conductor layer 3 is disposed on one surface S1 of the metal support layer 2 in the thickness direction. The conductor layer 3 has a first surface S11 and a second surface S12. The first surface S11 is the other surface of the conductor layer 3 in the thickness direction. The first surface S11 contacts the one surface S1 of the metal support layer 2. The second surface S12 is one surface of the conductor layer 3 in the thickness direction. The second surface S12 is disposed on the opposite side of the metal support layer 2 from the first surface S11 in the thickness direction. The second surface S12 contacts the first insulating layer 4. The conductor layer 3 is made of a copper plated layer.

[0028] Lightness L of the second surface S12 * is the second brightness. The second brightness may be equal to or greater than the first brightness, or may be less than the first brightness.

[0029] When the second brightness is equal to or greater than the first brightness, the difference between the second brightness and the first brightness is 7.0 or less. The difference between the second brightness and the first brightness may be 0. When the second brightness is equal to or greater than the first brightness and the difference between the second brightness and the first brightness is equal to or less than the upper limit value, the brightness L of the second surface S12 is 0. * , the lightness L of one side surface S1 of the metal support layer 2 *As a result, the lightness L of the fourth surface S14 of the conductive pattern 5 can be made to approach * and the lightness L of the second surface S12 * The difference can be secured.

[0030] When the second brightness is less than the first brightness, the difference between the second brightness and the first brightness is not more than 24.0, preferably not more than 10.0.

[0031] The second brightness is, for example, 51.0 to 82.0, or preferably 70.0 to 82.0.

[0032] Chromaticity a of the second surface S12 * is, for example, 22.0 or more, preferably 23.0 or more, and for example, 30.0 or less, preferably 28.0 or less.

[0033] Chromaticity b of the second surface S12 * is, for example, 17.0 or more, preferably 20.0 or more, and for example, 30.0 or less, preferably 29.0 or less.

[0034] (3) First insulating layer The first insulating layer 4 is disposed on one side of the conductor layer 3 in the thickness direction. The first insulating layer 4 is disposed on the second surface S12 of the conductor layer 3 in the thickness direction. The first insulating layer 4 is disposed between the conductor layer 3 and the conductor pattern 5 in the thickness direction. The first insulating layer 4 insulates the conductor layer 3 from the conductor pattern 5. The first insulating layer 4 is made of a 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 equal to or less than the above-mentioned upper limit, illumination light from the inspection device enters from one side of the first insulating layer 4, passes through the first insulating layer 4, and reaches the second surface S12 of the conductor layer 3. The illumination light that reaches the second surface S12 of the conductor layer 3 is reflected by the second surface S12 of the conductor layer 3. Here, when the thickness of the first insulating layer 4 is equal to or less than the above-mentioned upper limit, the illumination light that enters the first insulating layer 4 (incident light) and the light that is reflected by the second surface S12 of the conductor layer 3 (reflected light) are hardly absorbed or diffused within the first insulating layer 4. Therefore, the reflected light from the second surface S12 of the conductor layer 3 is likely to reach the inspection device without being absorbed or diffused much within the first insulating layer 4. This makes it difficult to ensure a gloss difference between the conductor layer 3 and the conductor pattern 5.

[0036] However, in the wired circuit board according to the embodiment, the lightness L * and the lightness L of the second surface S12 of the conductor layer 3. * Since the difference is ensured, even if the thickness of the first insulating layer 4 is equal to or less than the above upper limit, the difference in gloss can be ensured between the conductor layer 3 and the conductor pattern 5. The thickness of the first insulating layer 4 is, for example, 5 μm or more.

[0037] (4) 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 disposed on one surface of the first insulating layer 4 in the thickness direction. The conductor pattern 5 is disposed on the opposite side of the conductor layer 3 with respect to the first insulating layer 4 in the thickness direction. The conductor pattern 5 has a third surface S13 and a fourth surface S14. The third surface S13 is the other surface of the conductor pattern 5 in the thickness direction. The third surface S13 contacts one surface of the first insulating layer 4. The fourth surface S14 is one surface of the conductor pattern 5 in the thickness direction. The fourth surface S14 is disposed on the opposite side of the first insulating layer 4 with respect to the third surface S13 in the thickness direction. The fourth surface S14 contacts the first insulating layer 4. The conductor pattern 5 is made of a copper plating layer.

[0038] Lightness L of the 4th surface S14* is the lightness L of one surface S1 of the metal support layer 2 * (first brightness) and the brightness L of the second surface S12 of the conductor layer 3 * (2nd brightness) Higher. Lightness L of 4th surface S14 * For example, is greater than 82.0 and less than or equal to 90.0.

[0039] (5) 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 disposed on one surface of the first insulating layer 4 in the thickness direction. The second insulating layer 6 is made of a 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 conductive pattern 5.

[0040] 2. Manufacturing method of printed circuit board The method for manufacturing the wired circuit board 1 includes a conductor layer forming process (see FIG. 2A), a roughening process (see FIG. 2B), a first insulating layer forming process (see FIG. 2C), a conductor pattern forming process (see FIG. 2D), a second insulating layer forming process (see FIG. 1), and an inspection process (see FIG. 3).

[0041] (1) Conductor layer formation process 2A, in the conductor layer forming step, the conductor layer 3 is formed on one surface S1 of the metal support layer 2. The conductor layer 3 is formed over the entire one surface S1 of the metal support layer 2 by, for example, electrolytic plating.

[0042] (2) Roughening process Next, as shown in FIG. 2B, in the roughening step, the second surface S12 of the conductor layer 3 is roughened to reduce the brightness L *The roughening step is performed after the conductor layer forming step and before the first insulating layer forming step. In the roughening step, the second surface S12 of the conductor layer 3 is roughened by etching. The etching may be wet etching or dry etching. A preferred example of an etchant used in wet etching is a sulfuric acid / hydrogen peroxide etchant. When the etchant used in wet etching is a sulfuric acid / hydrogen peroxide etchant, excessive discoloration of the second surface S12 can be suppressed.

[0043] (3) First insulating layer formation process Next, as shown in FIG. 2C, in the first insulating layer forming step, a first insulating layer 4 is formed on the second surface S12 of the conductor layer 3.

[0044] More specifically, in the first insulating layer forming step, first, a photosensitive resin solution (varnish) is applied to the second surface S12 of the conductor layer 3 and then dried, thereby forming a photosensitive resin coating on the second surface S12.

[0045] Next, the photosensitive resin coating is exposed to light and developed, thereby obtaining the first insulating layer 4.

[0046] (4) Conductor pattern formation process Next, as shown in FIG. 2D, in the conductive pattern forming step, conductive pattern 5 is formed on first insulating layer 4.

[0047] Specifically, first, a seed layer is formed on one surface of the first insulating layer 4 in the thickness direction. The seed layer is formed by, for example, sputtering. Examples of materials for the seed layer include chromium, copper, nickel, titanium, and alloys thereof.

[0048] The seed layer is then coated with a plating resist.

[0049] Next, the plating resist is exposed to light and developed, whereby the plating resist is removed from the area where the conductive pattern 5 is to be formed, exposing the seed layer in the area where the conductive pattern 5 is to be formed. On the other hand, the plating resist remains in the area where the conductive pattern 5 is not to be formed.

[0050] Next, a conductive pattern 5 is formed on the exposed seed layer by electrolytic plating. After the electrolytic plating is completed, the plating resist is stripped off, and the seed layer exposed by the stripping of the plating resist is removed by etching.

[0051] As a result, the conductive pattern 5 is formed on the first insulating layer 4.

[0052] (5) Second insulating layer formation process Next, as shown in FIG. 1, in the second insulating layer forming step, a second insulating layer 6 is formed on the first insulating layer 4.

[0053] More specifically, in the second insulating layer forming step, first, a photosensitive resin solution (varnish) is applied onto the first insulating layer 4 and the conductive pattern 5 and dried to form a photosensitive resin coating.

[0054] Next, the photosensitive resin coating is exposed to light and developed, thereby forming the second insulating layer 6 on the first insulating layer 4.

[0055] (6) Inspection process Next, as shown in FIG. 3, in the inspection step, the shape of the conductive pattern 5 is inspected by image recognition.

[0056] In the inspection step, the conductive pattern 5 is photographed from one side in the thickness direction by the camera 10. At this time, the brightness L of the second surface S12 of the conductive layer 3 in the roughening step described above is * Since the second brightness is lowered, the brightness L * and the lightness L of the second surface S12 of the conductor layer 3. * The difference can be secured.

[0057] As a result, the accuracy of reading the shape of the conductive pattern 5 by image recognition can be improved.

[0058] 3. Effects (1) According to the wired circuit board 1, as shown in FIG. 1, the lightness L * (second brightness) is the brightness L of the one surface S1 of the metal support layer 2 * The brightness is equal to or greater than the first brightness and the difference from the first brightness is 7.0 or less, or the brightness is less than the first brightness and the difference from the first brightness is 24.0 or less.

[0059] Therefore, the lightness L of the second surface S12 of the conductor layer 3 * , the lightness L of one side surface S1 of the metal support layer 2 * can be approached.

[0060] As a result, the lightness L of the fourth surface S14 of the conductive pattern 5 * and the lightness L of the second surface S12 of the conductor layer 3. * The difference can be secured.

[0061] As a result, the accuracy of reading the shape of the conductive pattern 5 by image recognition can be improved.

[0062] (2) According to the method for manufacturing the wired circuit board 1, as shown in FIG. 2B, the brightness L * , and the lightness L of the surface S1 of the metal support layer 2 is reduced. * can be approached.

[0063] As a result, the lightness L of the fourth surface S14 of the conductive pattern 5 * and the lightness L of the second surface S12 of the conductor layer 3. * The difference can be secured.

[0064] As a result, the accuracy of reading the shape of the conductive pattern 5 by image recognition can be improved. [Example]

[0065] The present invention will be described in more detail below with reference to examples and comparative examples. It should be noted that the present invention is not limited to these examples and comparative examples. The specific numerical values ​​of the blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be substituted with the upper limit (a numerical value defined as "equal to or less than") or lower limit (a numerical value defined as "equal to or more than" or "exceeding") of the corresponding blending ratios (content ratios), physical property values, parameters, etc. described in the "Description of the Invention" above.

[0066] (1) Example 1 First, a metal support layer made of a copper alloy was prepared.

[0067] FIG. 4 shows an image of one surface of the metal support layer (corresponding to one surface S1 in FIG. 2A) photographed with a CCD camera. * The chromaticity a of the surface of one side of the metal support layer was 74.9. * is 10.8, and the chromaticity b * was 14.1.

[0068] Next, a conductor layer was formed on one surface of the metal support layer by electrolytic plating (conductor layer forming step).

[0069] FIG. 5 shows an image of the surface of the conductor layer (corresponding to the second surface S12 of the conductor layer 3 in FIG. 2A) photographed with a CCD camera. * The chromaticity of the surface of the conductor layer was 89.4. * is 20.2, and the chromaticity b * was 19.0.

[0070] Next, the surface of the conductor layer was roughened by wet etching using a sulfuric acid / hydrogen peroxide etching solution (roughening step).

[0071] Figure 6 shows an image of the roughened surface of the conductor layer taken with a CCD camera. * , chromaticity a * , and chromaticity b* is shown in Table 1.

[0072] Next, a photosensitive polyimide solution (varnish) was applied to the roughened surface of the conductor layer and dried, thereby forming a photosensitive polyimide coating film on the roughened surface of the conductor layer.

[0073] Next, the photosensitive polyimide coating was exposed to light and developed, thereby forming a first insulating layer made of polyimide on the roughened surface of the conductor layer (first insulating layer forming step).

[0074] Next, a seed layer made of chromium was formed on the first insulating layer by sputtering.

[0075] Next, a plating resist was applied to the first insulating layer, and the plating resist was exposed and developed, which removed the plating resist from the area where the conductive pattern was to be formed, exposing the seed layer in the area where the conductive pattern was to be formed.

[0076] Next, a conductor pattern made of copper was formed on the exposed seed layer by electrolytic plating. After the electrolytic plating was completed, the plating resist was stripped off, and the seed layer exposed by the stripping of the plating resist was removed by etching. This resulted in the formation of a conductor pattern on the first insulating layer (conductor pattern forming step).

[0077] Next, a photosensitive polyimide solution (varnish) was applied onto the first insulating layer and the conductive pattern and dried to form a photosensitive polyimide coating film.

[0078] Next, the photosensitive polyimide coating film was exposed to light and developed, thereby forming a second insulating layer on the first insulating layer (second insulating layer forming step). In this way, a wired circuit board was obtained.

[0079] Next, the conductor pattern of the obtained wiring circuit board was photographed with a CCD camera, and the shape of the conductor pattern was read by image recognition.

[0080] Figure 7A shows the photographed image of the conductor pattern. In the photographed image, the difference in brightness between the conductor pattern and the conductor layer is maintained. Therefore, the shape of the conductor pattern could be read by image recognition.

[0081] (2) Comparative Example A wired circuit board was produced in the same manner as in Example 1, except that the surface of the conductor layer was not roughened, and the conductor pattern of the obtained wired circuit board was photographed with a camera.

[0082] 7B shows the photographed image of the conductive pattern. In the comparative example, the difference in brightness between the conductive pattern and the conductive layer was smaller than in Example 1.

[0083] Therefore, in the comparative example, the shape of the conductor pattern could not be read by image recognition.

[0084] (3) Example 2 A wired circuit board was produced in the same manner as in Example 1, except that the surface of the conductor layer was roughened by changing the etching conditions in the roughening step. * , chromaticity a * , and chromaticity b * is shown in Table 1.

[0085] In Example 2, similarly to Example 1, the shape of the conductor pattern could be read.

[0086] (4) Example 3 A wired circuit board was produced in the same manner as in Example 1, except that the surface of the conductor layer was roughened using an alkaline etching solution in the roughening step. * , chromaticity a * , and chromaticity b * is shown in Table 1.

[0087] Although the shape of the conductor pattern could be read in Example 3, there was a significant discoloration of the surface of the conductor layer, and there was concern about a decrease in reading accuracy.

[0088] [Table 1] [Explanation of symbols]

[0089] 1 Wiring circuit board 2 Metal support layer 3 Conductor Layer 4. First insulating layer (an example of an insulating layer) 5 Conductor pattern S1 One side surface of the metal support layer S11 First surface of the conductor layer S12 Second side of the conductor layer

Claims

1. Lightness L of one side surface in the thickness direction ＊ a metal support layer having a first lightness; a first surface disposed on the one surface of the metal support layer in the thickness direction and in contact with the one surface of the metal support layer; and a second surface disposed on the opposite side of the metal support layer with respect to the first surface, and the lightness of the second surface is L ＊ a conductor layer having a second lightness; an insulating layer disposed on the second surface of the conductor layer in the thickness direction; a conductor pattern disposed on the opposite side of the conductor layer with respect to the insulating layer in the thickness direction; Equipped with the conductor layer and the conductor pattern are made of a copper plating layer, the metal support layer is made of a metal different from that of the conductor layer and the conductor pattern; The second brightness is The brightness is equal to or greater than the first brightness and the difference from the first brightness is 7.0 or less, or The wired circuit board has a brightness that is less than the first brightness and has a difference from the first brightness of 24.0 or less.

2. The printed circuit board according to claim 1 , wherein the metal support layer is made of a copper alloy.

3. the insulating layer is made of polyimide, 2. The printed circuit board according to claim 1, wherein the insulating layer has a thickness of 50 [mu]m or less.

4. Chromaticity a of the second surface ＊ The wired circuit board according to claim 1, wherein the modulus of elasticity is 22.0 or more.

5. Chromaticity b of the second surface ＊ The wired circuit board according to claim 4, wherein the modulus of elasticity is 17.0 or more.

6. A method for producing the wired circuit board according to any one of claims 1 to 5, a conductor layer forming step of forming the conductor layer on the one surface of the metal support layer; a roughening step of roughening the second surface of the conductor layer to reduce the second brightness; an insulating layer forming step of forming the insulating layer on the second surface of the conductor layer; a conductor pattern forming step of forming the conductor pattern on the insulating layer; A method for manufacturing a wired circuit board, comprising:

7. The method for producing a wired circuit board according to claim 6 , wherein in the roughening step, the second surface of the conductor layer is roughened by etching.

8. The method for producing a wired circuit board according to claim 6, further comprising an inspection step of inspecting the shape of the conductor pattern by image recognition.

Images