JP2007180089A - Method for manufacturing resin molded part having circuit conductor pattern - Google Patents

Abstract

A method of manufacturing a resin molded part having a circuit conductor pattern, which can form a high-definition circuit conductor pattern on a three-dimensional surface of a resin molded body having a three-dimensional shape and can reduce the manufacturing cost thereof. To provide.
A surface of a resin molded body is coated with a resist, and a portion of the resist is removed by laser irradiation along a predetermined circuit conductor pattern to expose the resin surface. Then, a copper base layer 4 is formed by metal vapor deposition, and then a metal layer 5 is formed on the base layer 4 by copper electroplating to form a circuit conductor having a predetermined thickness. In this case, a part of the resist 2 may be removed by laser irradiation to expose the resin surface, and at the same time, the exposed resin surface 3 may be roughened and / or activated.
[Selection] Figure 1

Description

  The present invention relates to a method for producing a resin molded part having a circuit conductor pattern. More specifically, the present invention relates to a resin molding having a circuit conductor pattern in which a circuit pattern is formed on a three-dimensional surface of a three-dimensional resin molded body using laser light. The present invention relates to a part manufacturing method.

  Conventionally, as a method of forming a circuit conductor pattern on a three-dimensional surface of a resin molded body having a three-dimensional shape formed by injection molding or the like, there are a two-time molding method and a photographic method.

  For example, in the two-time molding method, a catalyst that makes it easy to plate the surface of the primary molded body on which a predetermined pattern is formed by a mold is applied, and the liquid plastic is applied to the primary molded body so that only the predetermined pattern surface is exposed. This is a method of performing electroless plating on the surface of the predetermined pattern after injection molding. The photographic method is formed by forming a metal plating layer and a photoresist layer in order from the bottom on the surface of the resin molded body, and further placing a photomask formed in a predetermined pattern on the photoresist layer and then exposing from above. In this method, the metal plating layer is etched along the exposed pattern.

  These methods are performed using a mold or photomask formed in a predetermined shape. Therefore, when changing the design of the circuit conductor pattern, it is necessary to newly produce a mold or photomask having another shape, and the design change is not easy. In view of this, various methods for freely forming a circuit pattern on a resin molded body having a three-dimensional shape using laser light have been proposed so as to easily cope with a design change or the like.

  For example, in Patent Document 1, after applying a catalyst for easily plating the surface of the resin molded body in advance, a resist is entirely coated thereon, and a part of the resist is removed by laser irradiation to remove the resin surface. A method of forming a circuit conductor pattern by exposing and exposing the exposed resin surface by electroless plating is disclosed.

  In Patent Document 2, the entire surface of one surface of the resin molded body is subjected to base plating, a plating resist is coated on the plating, a part of the plating resist is removed by laser irradiation, and the base plating is exposed. There is disclosed a method of forming a circuit conductor pattern by forming a circuit conductor on the exposed portion by metal plating and removing the base plating other than the circuit conductor portion by etching.

  Patent Document 3 discloses a method that does not use a resist, unlike the above two Patent Documents. That is, a metal layer was formed on the surface of the resin molded body by physical vapor deposition, the boundary between the circuit-formed portion and the non-formed portion of this metal layer was removed by laser irradiation, and electrolytic plating was performed on the circuit-formed portion of the metal layer. Thereafter, the circuit conductor pattern is formed by removing only the metal layer of the circuit non-formation portion by soft etching.

JP-A-6-334308 JP-A-8-195544 Japanese Patent No. 3491630

  However, in Patent Document 1, a catalyst for facilitating plating is applied to the surface of the resin molded body before the laser irradiation performed to remove a part of the resist coated on the surface of the resin molded body. Therefore, laser irradiation may damage this catalyst and reduce the effect of surface treatment for plating. As a result, there is a problem that uneven plating or the like occurs in the subsequent electroless plating, and a high-definition circuit conductor pattern cannot be formed.

  Further, Patent Document 2 has a problem that when the base plating other than the circuit conductor portion is removed by etching, the surface and side surfaces of the circuit conductor portion are also etched, so that a high-definition circuit conductor pattern cannot be formed.

  In Patent Document 3, the boundary between the circuit-formed portion and the non-formed portion of the metal layer is removed by laser irradiation, but it is necessary to use a short wavelength laser such as ultraviolet rays for removing the metal layer. Since the short wavelength laser generator is more expensive than a laser generator such as an infrared laser used for removing the resist, there is a problem that manufacturing equipment becomes expensive.

  In addition, there is a method of using a special resin and irradiating it with a laser, and then performing metal plating on the laser-irradiated part to form a circuit conductor pattern on the surface of the resin molded body. Therefore, the material cost becomes high and the application range is limited.

  The problem to be solved by the present invention is to have a circuit conductor pattern that can form a high-definition circuit conductor pattern on a three-dimensional surface of a three-dimensionally shaped resin molded body and can reduce the manufacturing cost thereof. It is providing the manufacturing method of a resin molded component.

  In order to solve the above problems, a manufacturing method according to the present invention comprises coating a resist on the surface of a resin molded body, and removing a part of the resist by laser irradiation along a predetermined circuit conductor pattern to expose the resin surface. The gist is to perform a ground treatment for forming a circuit conductor on the exposed resin surface, and then form a circuit conductor on the ground-treated portion by metal plating.

  In this case, it is desirable that the resin surface is exposed by removing a part of the resist by the laser irradiation, and at the same time, the exposed resin surface is roughened and / or activated.

  Further, it is preferable that a conductive base layer is formed by depositing a conductive metal on the exposed resin surface by the base treatment, and then electrolytic plating is performed on the base layer.

  Alternatively, it is desirable to apply an electroless plating catalyst to the exposed resin surface by the base treatment, and then perform electroless plating.

  Furthermore, it is desirable to remove the resist on which the circuit pattern is formed before or after metal plating on the ground-treated portion.

  According to the manufacturing method of the present invention, after removing a part of the resist coated on the surface of the resin molded body by laser irradiation to expose the resin surface, a circuit conductor is formed on the exposed resin surface. Therefore, the ground surface is not roughened by laser irradiation. Moreover, since the etching process for removing a part of the metal layer is not performed, the surface and side surfaces of the circuit conductor portion are not roughened by the etching. And since a high-definition circuit pattern is freely formed on the surface of a resin molding using a laser beam, and a base treatment and metal plating are performed along this, a high-definition circuit conductor pattern can be formed.

  In addition, since there is no treatment for removing the metal layer, it is not necessary to use a short wavelength laser such as ultraviolet rays. Furthermore, no special resin is used. For this reason, the equipment cost and material cost are not increased, and the manufacturing cost can be reduced as compared with the conventional method.

  In this case, when the resin surface is exposed by removing a part of the resist by laser irradiation and the exposed resin surface is roughened, fine irregularities are formed on the resin surface. The adhesion of metal plating performed on the exposed resin surface can be improved. Moreover, when this exposed resin surface is activated at the same time, polar groups such as hydroxyl groups and amino groups are imparted to the resin surface due to this activation, and the affinity between the resin surface and metal plating is increased. The adhesion of metal plating to the surface can be improved. Furthermore, since the resist removal and the roughening / activation of the resin surface can be performed at the same time with the same laser device, the manufacturing process can be shortened and simplified.

  Then, by conducting the base treatment, a conductive metal is deposited on the exposed resin surface to form a conductive base layer, and then electroplated on the base layer, or exposed by the base treatment. If a catalyst for electroless plating is applied to the surface of the resin, and then electroless plating is performed, a high-definition circuit conductor pattern can be formed more reliably.

  Furthermore, if the resist on which the circuit pattern is formed is removed before or after metal plating on the ground-treated portion, the ground treatment and metal plating are applied to the surface of the resin molded body on which the circuit conductor pattern is to be formed with high definition. Will be.

  Hereinafter, the production method according to the present invention (hereinafter referred to as the present production method) will be described in detail. This manufacturing method includes steps 1 to 4.

  In this manufacturing method, step 1 is a step of coating a resist on the surface of the resin molded body on which the circuit conductor pattern is formed.

  The resin molded body can be produced by molding a resin into a predetermined shape by a molding method such as injection molding or extrusion molding. As resin used here, what is excellent in a moldability and heat resistance is preferable. For example, a thermoplastic resin can be suitably used because it has a very good moldability, but may be a thermosetting resin. In addition, since a circuit conductor is formed on the resin surface and soldering or the like may be performed on the circuit, it is preferable to have heat resistance enough to withstand soldering. For example, an ordinary lead-containing solder may have a heat resistance of 200 ° C. or higher, and a lead-free solder containing a high amount of tin may have a heat resistance of 250 ° C. or higher.

  Examples of the resin that meets the moldability and heat resistance conditions as described above include polyamide, polyphenylene sulfide, liquid crystal polymer, and polyester.

  The resist may be any resist that can remove a part of the resist irradiated by laser irradiation performed in the next step, that is, a resist that can be sufficiently decomposed by the energy of laser light. For example, an acrylic ink etc. can be illustrated. The resist can be appropriately selected depending on the type of resin to be molded, the laser device to be used, and the irradiation conditions. Coating of the resist on the surface of the resin molded body can be performed by a commonly used wet coating method such as spraying or dipping.

  Step 2 is a step of exposing a resin surface by removing a part of the resist coated on the surface of the resin molded body by laser irradiation along a predetermined circuit conductor pattern.

  The circuit conductor pattern is predetermined by a computer or the like, and can be freely changed in design. Then, based on a predetermined circuit conductor pattern determined in advance, laser irradiation is performed on the resist coated on the surface of the resin molded body by computer control, and a part of the resist is removed.

  The laser beam used for laser irradiation may be any laser beam that can decompose and remove the resist, such as a YAG laser or a carbon dioxide laser. Such a laser beam selectively irradiates the circuit pattern forming portion of the resist.

  When a part of the resist is removed by laser irradiation, the laser irradiation conditions may be optimized, and the exposed resin surface may be roughened and / or activated. The roughening or activation of the resin surface is for facilitating the base treatment performed in the next step. For example, when a metal layer, a plating catalyst, or the like is formed on the resin surface as a base treatment, there is an effect that these are easily formed in close contact with the resin surface.

  Roughening of the resin surface can be performed by roughening the surface by partially scattering the resin surface material by laser irradiation. Since the circuit conductor is formed by metal plating on the roughened surface, the surface may be roughened to such a degree that the surface irregularities of the circuit conductor are not affected.

  In addition, activation of the resin surface is achieved by causing plasma generated by laser irradiation to cause ions such as oxygen and nitrogen in the plasma to act on the resin surface and causing polar functional groups such as oxygen polar groups and nitrogen polar groups to form molecules on the resin surface. It can be performed by giving to. As a result, the affinity between the resin surface and the metal increases, and the adhesion of the metal to the resin surface increases.

  This roughening and / or activation may be performed at the same time as removing the resist to expose the resin surface, or after removing the resist, changing the irradiation conditions and irradiation conditions in resist removal. There may be.

  For example, the power of the laser beam is adjusted in advance to an energy density sufficient to roughen and / or activate the resin surface so that the resist removal and the roughening and / or activation of the resin surface can be performed simultaneously. It may be controlled by a computer. In addition, when removing the resist, the laser beam power is set to be high so that the resist can be removed quickly, and the laser beam power is lowered at the stage of roughening and / or activating the resin surface. The resist removal and the roughening and / or activation of the resin surface may be controlled by a computer by laser irradiation.

  Step 3 is a step of performing a base treatment for forming a circuit conductor on the exposed resin surface.

  Examples of the base treatment include a process for forming a conductive base layer by depositing a conductive metal on the exposed resin surface, and a process for applying an electroless plating catalyst to the exposed resin surface. can do.

  In the case of forming a conductive underlayer on the exposed resin surface, examples of methods for depositing a conductive metal on the resin surface include physical vapor deposition methods such as sputtering, vacuum deposition, and ion plating. it can. In the physical vapor deposition method, a resin molded body for forming an underlayer is placed in a chamber, the inside of the chamber is evacuated and depressurized, and then the above various known vapor deposition methods can be used. In addition, since these vapor deposition methods can be performed using a well-known vapor deposition apparatus, detailed description is abbreviate | omitted.

  Examples of the conductive metal forming the base layer include simple substances or alloys such as copper, nickel, gold, silver, aluminum, titanium, chromium, molybdenum, tungsten, tin, and lead. In consideration of conductivity and cost, copper and nickel are preferable. This underlayer may be formed to a thickness that enables electrolytic plating performed in the next step. For example, a thickness of about several tens of nanometers or more is sufficient.

  On the other hand, when an electroless plating catalyst is applied to the exposed resin surface, the resin is immersed in a catalyst solution to adsorb palladium-tin colloid on the surface, and then excess tin is removed to expose palladium. There is.

  Step 4 is a step of performing metal plating on the portion subjected to the ground treatment in step 3.

  In the case where a conductive ground layer is formed as a ground treatment in Step 3, electrolytic plating is performed on the ground-treated portion in Step 4. Examples of the metal used for electrolytic plating include gold, silver, copper, and nickel, but are not particularly limited as long as they have good conductivity. In consideration of material costs and the like, it is preferable to use copper. By this electrolytic plating, a circuit conductor pattern having a predetermined thickness is formed. For example, a circuit conductor having a thickness of 10 μm or more can be formed in a short time.

  On the other hand, when an electroless plating catalyst is applied as a base treatment in step 3, electroless plating is performed on the base-treated portion in step 4. Similarly, examples of the metal used for the electroless plating include copper and nickel, but are not particularly limited as long as they have good conductivity.

  In the case of electroless plating, when the formation rate of plating is not so high, after electroless plating to a thickness capable of electrolytic plating, plating may be formed to a predetermined thickness by electrolytic plating. At this time, the metal to be electrolessly plated and the metal to be electroplated may be the same or different. A circuit conductor pattern having a predetermined thickness is formed by only electroless plating or a combination of electroless plating and electrolytic plating.

  The remaining resist after the circuit pattern is formed by laser irradiation is immersed in an alkaline solution after the base treatment in step 3 and before or after metal plating in step 4. And remove it.

  Next, a first embodiment of the manufacturing method will be described with reference to FIG. As shown in FIG. 1A, a resin molded body 1 is manufactured by injection molding a resin into a predetermined shape. Next, as shown in FIG. 1B, a resist 2 is uniformly coated on the surface of the resin molded body 1. Next, as shown in FIG. 1C, the irradiation conditions are optimized, and a part of the resist 2 is removed along a predetermined circuit conductor pattern by laser irradiation of a YAG laser to expose the resin surface. At this time, the exposed resin surface 3 is also roughened and activated by laser irradiation. Next, as shown in FIG. 1D, copper metal vapor deposition is performed to form a conductive base layer 4 on the exposed resin surface 3. At this time, copper is also deposited on the resist 2 to form a deposited film 4 '. Next, as shown in FIG. 1E, the remaining resist 2 is dipped and removed together with the deposited film 4 'deposited thereon by dipping in an alkaline solution. Next, as shown in FIG. 1 (f), a copper plating 5 is deposited on the underlayer 4 to have a predetermined thickness by electrolytic plating. As described above, the circuit conductor pattern is formed on the three-dimensional surface of the resin molded body 1.

  Moreover, 2nd embodiment of this manufacturing method is described using FIG. Since FIG. 2A to FIG. 2C are the same steps as FIG. 1A to FIG. 1C, description thereof will be omitted. After the step shown in FIG. 2 (c), the palladium catalyst 6 is adsorbed on the exposed resin surface 3 as shown in FIG. 2 (d). Next, as shown in FIG. 2E, a copper plating 7 having a predetermined thickness is deposited on the resin surface 3 on which the palladium catalyst 6 is adsorbed by electroless plating. Next, as shown in FIG. 2F, the remaining resist 2 is stripped and removed by dipping in an alkaline solution. As described above, the circuit conductor pattern is formed on the three-dimensional surface of the resin molded body 1.

  As described above, according to the manufacturing method having such a configuration, after removing a part of the resist coated on the surface of the resin molded body by laser irradiation to expose the resin surface, the circuit conductor is applied to the exposed resin surface. Since the ground treatment for forming is performed, the ground surface is not roughened by laser irradiation. Moreover, since the etching process for removing a part of the metal layer is not performed, the surface and side surfaces of the circuit conductor portion are not roughened by the etching. And since a high-definition circuit pattern is freely formed on the surface of a resin molding using a laser beam, and a base treatment and metal plating are performed along this, a high-definition circuit conductor pattern can be formed.

  In addition, since there is no treatment for removing the metal layer, it is not necessary to use a short wavelength laser such as ultraviolet rays. Furthermore, no special resin is used. For this reason, the equipment cost and material cost are not increased, and the manufacturing cost can be reduced as compared with the conventional method.

  In this case, when the resin surface is exposed by removing a part of the resist by laser irradiation and the exposed resin surface is roughened, fine irregularities are formed on the resin surface. The adhesion of the metal plating performed on the exposed resin surface can be improved. Roughening of the resin surface is usually performed using an etching solution such as chromic acid / sulfuric acid / potassium hydroxide / hydrofluoric acid / nitric acid / acidic ammonium fluoride / nitric acid. The process can be shortened and simplified, and the use of chemical substances and waste liquid can be reduced.

  Further, when the exposed resin surface is activated at the same time, polar groups such as hydroxyl groups and amino groups are imparted to the resin surface by the activation. Thereby, the affinity between the resin surface and the metal plating is increased, and the adhesion can be improved.

  Furthermore, since the resist removal and the roughening / activation of the resin surface can be performed at the same time with the same laser generator, the manufacturing process can be shortened and simplified.

  Then, by conducting the base treatment, a conductive metal is deposited on the exposed resin surface to form a conductive base layer, and then electroplated on the base layer, or exposed by the base treatment. If a catalyst for electroless plating is applied to the surface of the resin, and then electroless plating is performed, a high-definition circuit conductor pattern can be formed more reliably.

  When metal deposition is performed in the base treatment, and then electrolytic plating is performed, a circuit conductor pattern having a predetermined thickness can be rapidly formed. On the other hand, when a catalyst for electroless plating is applied in the base treatment and then electroless plating is performed (electroplating may be combined), a circuit conductor pattern with a predetermined thickness can be easily formed by a wet method only on the plating line. can do.

  Furthermore, if the resist on which the circuit pattern is formed is removed before or after metal plating on the ground-treated portion, the ground treatment and metal plating are applied to the surface of the resin molded body on which the circuit conductor pattern is to be formed with high definition. Will be.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited to the said embodiment at all, A various change is possible in the range which does not deviate from the summary of this invention.

  For example, the remaining resist is removed at an appropriate stage after step 3, but this resist removing step may be omitted if there is no problem depending on the state of use.

  The method for producing a resin molded part having a circuit conductor pattern according to the present invention can be used, for example, as a method for producing a housing in which an electronic element is mounted or a mechanical part in a portable electronic device or an automotive electronic device.

It is process drawing showing 1st embodiment of the manufacturing method which concerns on this invention. It is process drawing showing 2nd embodiment of the manufacturing method which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin molding 2 Resist 3 Exposed resin surface 4 Underlayer 5 Copper plating 6 Palladium catalyst 7 Copper plating

Claims (5)

  In order to form a circuit conductor on the exposed resin surface by coating a resist on the surface of the resin molded body, removing a part of the resist by laser irradiation along a predetermined circuit conductor pattern to expose the resin surface A method for producing a resin molded part having a circuit conductor pattern, characterized in that a circuit conductor is formed on the portion subjected to the ground treatment by metal plating, and thereafter a metal conductor is formed.   2. The circuit conductor according to claim 1, wherein a part of the resist is removed by the laser irradiation to expose the resin surface, and at the same time, the exposed resin surface is roughened and / or activated. A method for producing a resin molded part having a pattern.   3. A conductive metal is deposited on the exposed resin surface by the base treatment to form a conductive base layer, and then electrolytic plating is performed on the base layer. A method for producing a resin molded part having the circuit conductor pattern according to 1.   3. The production of a resin molded part having a circuit conductor pattern according to claim 1, wherein a catalyst for electroless plating is applied to the exposed resin surface by the base treatment, and then electroless plating is performed. Method.   5. The resin molded part having a circuit conductor pattern according to claim 1, wherein the resist on which the circuit pattern is formed is removed before or after metal plating on the ground-treated portion. Manufacturing method.

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