Substrate manufacturing method and substrate manufacturing system

Abstract

A substrate manufacturing method and a substrate manufacturing system are provided that can improve the smoothness of an end face formed by etching. [Solution] The method for manufacturing the wired circuit board 1 includes an etching step of etching a portion of the stainless steel substrate M using a first etching liquid, and a post-treatment step of treating the end surface S formed by the etching step with a second etching liquid. The first etching liquid is capable of dissolving iron in the stainless steel. The second etching liquid is capable of dissolving metal that was not dissolved in the etching step and remains on the end surface S.

Description

[Technical Field]

[0001] The present invention relates to a substrate manufacturing method and a substrate manufacturing system. [Background technology]

[0002] Conventionally, a method has been known in which a suspension board with a circuit is obtained by sequentially forming an insulating base layer, a conductor layer, and an insulating cover layer on a suspension board made of a metal such as stainless steel, and then etching the suspension board into a predetermined shape (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-217250 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method described in Patent Document 1, metals in the stainless steel that are difficult to dissolve in the etching solution may remain on the etched end surface, which may reduce the smoothness of the end surface.

[0005] The present invention provides a substrate manufacturing method and a substrate manufacturing system that can improve the smoothness of an end face formed by etching. [Means for solving the problem]

[0006] The present invention [1] includes a method for manufacturing a substrate, which includes an etching step in which a part of a stainless steel substrate is etched with a first etching liquid to form an edge surface on the etched part, and a post-treatment step in which the edge surface formed by the etching step is treated with a second etching liquid, wherein in the etching step, the first etching liquid is capable of dissolving iron in the stainless steel, and in the post-treatment step, the second etching liquid is capable of dissolving metal other than iron that was not dissolved in the etching step and remains on the edge surface.

[0007] According to this method, in the post-treatment step, the metal that was not dissolved in the etching step and remains on the end surface can be dissolved with the second etching liquid.

[0008] Therefore, the metal remaining on the end face formed by etching can be removed, and the smoothness of the end face can be improved.

[0009] The present invention [2] includes the method for producing a substrate according to the above [1], wherein the metal is chromium.

[0010] According to this method, the chromium remaining on the end face formed by etching can be removed, and the smoothness of the end face can be improved.

[0011] The present invention [3] includes the method for manufacturing a substrate according to the above [1] or [2], wherein the substrate is a wired circuit board, and the wired circuit board comprises a metal support layer made of the stainless steel base material, a circuit pattern, and an insulating layer disposed between the metal support layer and the circuit pattern.

[0012] The present invention [4] includes a manufacturing system that can be used in any one of the substrate manufacturing methods [1] to [3] above, the manufacturing system for a substrate comprising an etching apparatus that performs the etching step and a post-processing apparatus that performs the post-processing step.

[0013] According to this configuration, a post-processing device that performs the post-processing step is provided.

[0014] Therefore, the metal remaining on the end face formed by etching can be removed by a post-treatment device, thereby improving the smoothness of the end face.

[0015] The present invention [5] includes the substrate manufacturing system according to the above [4], wherein the post-processing device is disposed downstream of the etching device in the flow direction in a continuous manufacturing line. [Effects of the Invention]

[0016] According to the substrate manufacturing method and substrate manufacturing system of the present invention, it is possible to improve the smoothness of the etched end face. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view of a printed circuit board. [Figure 2] 2A to 2C are diagrams showing a method for manufacturing the wired circuit board shown in FIG. 1, where FIG. 2A shows a first insulating layer forming step, FIG. 2B shows a circuit pattern forming step, and FIG. 2C shows a second insulating layer forming step. [Figure 3] 3A and 3B are diagrams following FIG. 2C and showing the method for producing a printed circuit board, with FIG. 3A showing the etching step and FIG. 3B showing the post-treatment step. [Figure 4] FIG. 4 is a block diagram showing a system for manufacturing a printed circuit board. [Figure 5] FIG. 5A is an SEM (scanning electron microscope) photograph showing a cross section of the substrate obtained in the example, and FIG. 5B is an SEM photograph showing a cross section of the substrate obtained in the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0018] 1. Wiring circuit board A wired circuit board 1 as an example of a substrate will be described with reference to Fig. 1. The wired circuit board 1 may be a flexible wired circuit board or a circuit-equipped suspension board.

[0019] The wired circuit board 1 has a metal support layer 2, a first insulating layer 3 as an example of an insulating layer, a circuit pattern 4, and a second insulating layer 5.

[0020] (1) Metal support layer The metal support layer 2 supports the first insulating layer 3, the circuit pattern 4, and the second insulating layer 5. The metal support layer 2 is made of a stainless steel substrate. The metal support layer 2 may consist of only the stainless steel substrate. The metal support layer 2 may also consist of a stainless steel substrate and a metal layer laminated on one surface of the substrate in the thickness direction. The metal layer may be laminated on the entire one surface of the substrate in the thickness direction, or on a portion of the one surface of the substrate in the thickness direction. The material of the metal layer is different from the material of the substrate (i.e., stainless steel). Examples of materials for the metal layer include gold, silver, copper, nickel, chromium, titanium, and alloys thereof.

[0021] (2) First insulating layer The first insulating layer 3 is disposed on one side of the metal support layer 2 in the thickness direction of the metal support layer 2. The first insulating layer 3 is disposed on one surface of the metal support layer 2 in the thickness direction. The first insulating layer 3 is disposed between the metal support layer 2 and the circuit pattern 4 in the thickness direction. The first insulating layer 3 insulates the metal support layer 2 from the circuit pattern 4. The first insulating layer 3 is made of a resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester.

[0022] (3) Circuit pattern The circuit pattern 4 is disposed on one side of the first insulating layer 3 in the thickness direction. The circuit pattern 4 is disposed on one surface of the first insulating layer 3 in the thickness direction. The circuit pattern 4 is disposed on the opposite side of the metal support layer 2 with respect to the first insulating layer 3 in the thickness direction. The circuit pattern 4 is made of a metal. Examples of metals include copper, silver, gold, iron, aluminum, chromium, and alloys thereof. The circuit pattern 4 is preferably made of copper. The shape of the circuit pattern 4 is not limited. The circuit pattern 4 has, for example, a plurality of wirings 41 and a plurality of terminals (not shown). The wirings 41 may be signal wirings that transmit electrical signals, or may be power wirings that transmit current from a power source.

[0023] (4) Second insulating layer The second insulating layer 5 covers all of the wiring 41. The second insulating layer 5 is disposed on the first insulating layer 3 in the thickness direction. The second insulating layer 5 does not cover the terminals. The second insulating layer 5 is made of a resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester.

[0024] 2. Manufacturing method of printed circuit board Next, a method for manufacturing the wired circuit board 1 will be described.

[0025] The method for manufacturing the wired circuit board 1 includes a first insulating layer forming step (see FIG. 2A), a circuit pattern forming step (see FIG. 2B), a second insulating layer forming step (see FIG. 2C), an etching step (see FIG. 3A), and a post-treatment step (see FIG. 3B).

[0026] (1) First insulating layer formation process As shown in FIG. 2A, in the first insulating layer forming step, a first insulating layer 3 is formed on one surface of a base material M made of stainless steel.

[0027] Specifically, in the first insulating layer forming step, a photosensitive resin solution (varnish) is first applied to one surface of the substrate M in the thickness direction and dried to form a photosensitive resin coating. Next, the photosensitive resin coating is exposed to light and developed. This results in the first insulating layer 3.

[0028] (2) Circuit pattern formation process Next, as shown in FIG. 2B, in the circuit pattern forming step, a circuit pattern 4 is formed on the first insulating layer 3.

[0029] Specifically, first, a seed layer is formed on one surface of the first insulating layer 3 and one surface of the substrate M 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.

[0030] The seed layer is then coated with a plating resist.

[0031] Next, the plating resist is exposed to light and developed, which removes the plating resist from the area where the circuit pattern 4 is to be formed, exposing the seed layer in the area where the circuit pattern 4 is to be formed. On the other hand, the plating resist remains in the area where the circuit pattern 4 is not to be formed.

[0032] Next, a circuit pattern 4 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.

[0033] As a result, the circuit pattern 4 is formed on the first insulating layer 3.

[0034] (3) Second insulating layer formation process Next, as shown in FIG. 2C, in the second insulating layer forming step, second insulating layer 5 is formed on first insulating layer 3.

[0035] More specifically, in the second insulating layer forming process, a photosensitive resin solution (varnish) is first applied onto the substrate M, the first insulating layer 3, and the circuit pattern 4, and then dried to form a photosensitive resin coating.

[0036] Next, the photosensitive resin coating is exposed to light and developed, thereby forming the second insulating layer 5 on the first insulating layer 3.

[0037] (4) Etching process Next, as shown in FIG. 3A, in the etching step, a part of the substrate M is etched using a first etching liquid.

[0038] More specifically, in the etching step, first, an etching resist R1 is formed on one surface of the base material M in the thickness direction, and then an etching resist R2 is formed on the other surface of the base material M in the thickness direction. The etching resist R1 covers the first insulating layer 3, the circuit pattern 4, and the second insulating layer 5. The etching resist R2 covers the portions of the base material M that are not to be etched, and exposes the portions of the base material M that are to be etched.

[0039] To form the etching resists R1 and R2, dry film photoresists are attached to one surface and the other surface of the base material M in the thickness direction, and the dry film photoresists are exposed and developed.

[0040] Next, the portion of the base material M exposed from the etching resist R2 (a part of the base material M) is etched using a first etching liquid.

[0041] In the etching step, the first etching solution is capable of dissolving iron in the stainless steel. Examples of the first etching solution include an aqueous solution of ferric chloride, an aqueous solution of cupric chloride, and an aqueous solution of sulfuric acid and hydrogen peroxide.

[0042] The portion etched by the first etching liquid has an end surface S. In other words, the substrate M after the etching step has an end surface S. The end surface S extends in the thickness direction.

[0043] Here, particles G made of a metal other than iron may not be dissolved and remain on the end surface S. The metal other than iron is a metal that is less likely to dissolve in the first etching solution than iron, and an example of such a metal is chromium.

[0044] After the etching step, the substrate M is washed with, for example, water to remove the first etching solution adhering to the substrate M. After washing, the etching resists R1 and R2 are stripped off before the post-treatment step. Note that the post-treatment step may be performed without stripping off the etching resists R1 and R2.

[0045] (5) Post-processing Next, as shown in Fig. 3B, in the post-processing step, the end surface S formed by the etching step is treated with a second etching solution. More specifically, in the post-processing step, metal particles G that were not dissolved in the etching step and remain on the end surface S are etched with the second etching solution.

[0046] In the post-treatment step, the second etching liquid can dissolve metal that was not dissolved in the etching step and remains on the end surface S. Metal particles G remaining on the end surface S are more easily dissolved by the second etching liquid than iron. The second etching liquid preferably does not dissolve iron.

[0047] Examples of the second etching solution include a ceric ammonium nitrate solution, a sodium hydroxide solution, a potassium permanganate solution, and a sodium metasilicate solution.

[0048] After the etching step, the substrate M is washed with, for example, water to remove the second etching liquid adhering to the substrate M.

[0049] Thereafter, the substrate M is dried to obtain the above-described wired circuit board 1.

[0050] 3. Wired circuit board manufacturing system Next, a manufacturing system 10 for the wired circuit board 1 that can be used in the manufacturing method for the wired circuit board 1 described above will be described.

[0051] 4, the manufacturing system 10 includes, for example, a continuous manufacturing line L. The manufacturing system 10 may include a plurality of manufacturing lines L. The manufacturing line L includes an etching apparatus 11, a cleaning apparatus 12, and a post-processing apparatus 13. That is, the manufacturing system 10 includes the etching apparatus 11, the cleaning apparatus 12, and the post-processing apparatus 13.

[0052] The production line L may perform the etching process and post-treatment process using a roll-to-roll method, or may perform the etching process and post-treatment process on a plurality of sheet-like substrates transported in the flow direction.

[0053] Furthermore, the production line L may be equipped, upstream of the etching device 11 in the flow direction of the production line L, with devices that can be used in the first insulating layer formation process (e.g., a coating device, a drying device, an exposure device, a developing device), devices that can be used in the circuit pattern formation process (e.g., a plating tank), and devices that can be used in the second insulating layer formation process (e.g., a coating device, a drying device, an exposure device, a developing device).

[0054] The etching device 11 performs the etching process described above. The etching device 11 is capable of spraying a first etching liquid onto the substrate M. The etching device 11 has, for example, a tank and a plurality of spray nozzles. The tank contains the first etching liquid. Each of the plurality of spray nozzles sprays the first etching liquid supplied from the tank toward the substrate M. The etching device 11 sprays the first etching liquid onto the substrate M from, for example, the other side in the thickness direction (see FIG. 3A). The etching device 11 may also spray the first etching liquid onto the substrate M from both sides in the thickness direction.

[0055] The cleaning device 12 cleans the substrate M after the etching process and before the post-treatment process. The cleaning device 12 is disposed downstream of the etching device 11 and upstream of the post-treatment device 13 in the flow direction of the production line L. The cleaning device 12 includes, for example, a tank and a plurality of spray nozzles. The tank contains a cleaning liquid. Examples of the cleaning liquid include water and acid. Each of the plurality of spray nozzles sprays the cleaning liquid supplied from the tank toward the substrate M.

[0056] The production line L may have multiple cleaning devices 12 using different cleaning liquids downstream of the etching device 11 and upstream of the post-treatment device 13 in the flow direction of the production line L. For example, the production line L may have a first cleaning device 12 using an acid as a cleaning liquid and a second cleaning device 12 using water as a cleaning liquid downstream of the etching device 11 and upstream of the post-treatment device 13 in the flow direction of the production line L. Examples of acids used in the first cleaning device 12 include sulfuric acid, hydrochloric acid, and nitric acid. The second cleaning device 12 is located downstream of the first cleaning device 12 in the flow direction of the production line L.

[0057] In addition, the production line L may be provided with a resist stripping device for stripping the etching resists R1 and R2 (see Figure 3A) downstream of the cleaning device 12 and upstream of the post-treatment device 13 in the flow direction of the production line L.

[0058] The post-treatment device 13 performs the above-described post-treatment process. The post-treatment device 13 is disposed downstream of the etching device 11 in the flow direction of the production line L. The post-treatment device 13 is disposed downstream of the cleaning device 12 in the flow direction of the production line L. The post-treatment device 13 is capable of spraying the second etching liquid onto the substrate M. The post-treatment device 13 has, for example, a tank and multiple spray nozzles. The tank contains the second etching liquid. Each of the multiple spray nozzles sprays the second etching liquid supplied from the tank toward the substrate M. The post-treatment device 13 sprays the second etching liquid onto the substrate M from, for example, the other side in the thickness direction (see FIG. 3B). The post-treatment device 13 may spray the second etching liquid onto the substrate M from both sides in the thickness direction. Alternatively, the post-treatment device 13 does not have to be capable of spraying the second etching liquid. The post-treatment device 13 may have a chemical tank that stores the second etching liquid, and the substrate M may be immersed in the second etching liquid in the chemical tank.

[0059] The production line L may be provided with a cleaning device that uses water as a cleaning liquid and a drying device downstream of the post-treatment device 13 in the flow direction of the production line L.

[0060] 4. Effects (1) As shown in Figures 3A and 3B, the method for manufacturing the wired circuit board 1 includes an etching step (see Figure 3A) in which a stainless steel substrate M is etched using a first etching liquid, and a post-treatment step (see Figure 3B) in which the end surface S formed by the etching step is treated with a second etching liquid. The first etching liquid is capable of dissolving iron in the stainless steel. The second etching liquid is capable of dissolving metal particles G that remain on the end surface S without being dissolved in the etching step.

[0061] This allows the metal particles G that are not dissolved in the etching step and remain on the end surface S to be dissolved in the second etching liquid in the post-treatment step.

[0062] Therefore, metal particles G remaining on the end surface S formed by etching can be removed, and the smoothness of the end surface S can be improved.

[0063] (2) According to the method for manufacturing the wired circuit board 1, the metal that is not dissolved in the etching step and remains on the end surface S is chromium.

[0064] Therefore, the chromium particles G remaining on the end surface S formed by etching can be removed, and the smoothness of the end surface S can be improved.

[0065] (3) As shown in FIG. 4, the manufacturing system 10 for the wired circuit board 1 includes an etching device 11 for carrying out the etching step and a post-processing device 13 for carrying out the post-processing step.

[0066] Therefore, the metal particles G remaining on the end surface S formed by etching can be removed by the post-treatment device 13, and the smoothness of the end surface S can be improved. [Example]

[0067] 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.

[0068] <Example> A stainless steel substrate used as a metal support layer of a printed circuit board was sprayed with a first etching solution (aqueous ferric chloride solution, liquid temperature: 50°C) for 120 seconds to etch the substrate (etching step), and then the substrate was washed with water.

[0069] Next, a second etching liquid (ceric ammonium nitrate solution, liquid temperature: 40° C.) was sprayed onto the substrate after the etching step for 40 seconds (post-treatment step).

[0070] In this way, a substrate was obtained. The end surface S (etched end surface) of the obtained substrate is shown in FIG. 5A.

[0071] <Comparative Example> A substrate was obtained in the same manner as in Example 1, except that the post-treatment step was not performed. The end face of the obtained substrate (the end face formed by etching) is shown in Figure 5B.

[0072] In the comparative example, metal particles G that were not dissolved in the etching process protrude from the end surface S. On the other hand, in the example (see FIG. 5A), such protrusions were small, and the end surface S was formed to be smoother than that of the comparative example. [Explanation of symbols]

[0073] 1. Wired circuit board (example of board) 2 Metal support layer 3 First insulating layer 4 Circuit Pattern 10 Manufacturing Systems L production line 11 Etching equipment 13 Aftertreatment device M Base material S End face formed by etching process G Metal particles remaining on the end surface S

Claims

1. an etching step in which a portion of the stainless steel substrate is etched using a first etching solution to form an end face in the etched portion; a post-treatment step of treating the end surface formed by the etching step with a second etching solution; Including, In the etching step, the first etching solution is capable of dissolving iron in the stainless steel, In the post-treatment step, the second etching liquid is capable of dissolving the metal other than iron that was not dissolved in the etching step and remains on the end surface.

2. The method for manufacturing a substrate according to claim 1 , wherein the metal is chromium.

3. the substrate is a wired circuit board, The printed circuit board is a metal support layer made of the stainless steel substrate; A circuit pattern, an insulating layer disposed between the metal support layer and the circuit pattern; The method for manufacturing a substrate according to claim 1 , comprising:

4. A manufacturing system that can be used in the method for manufacturing a substrate according to any one of claims 1 to 3, an etching apparatus for performing the etching step; a post-processing device that performs the post-processing step; A substrate manufacturing system comprising:

5. The substrate manufacturing system according to claim 4 , wherein the post-processing device is disposed downstream of the etching device in a flow direction in a continuous manufacturing line.

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