JP5471234B2 - Surface inspection method and manufacturing method of metal pattern forming resin substrate - Google Patents

Description

  The present invention relates to a method for inspecting a surface of a metal pattern forming resin substrate obtained by patterning a metal layer on a resin substrate, and a method for manufacturing a metal pattern forming resin substrate.

  A metal pattern forming resin substrate such as a circuit board is manufactured by removing a part of the metal layer by a method such as etching from the metal layer laminated substrate obtained by laminating the metal layer on the resin substrate. However, on the surface of the resin between the metal patterns where the metal layer is exposed by removing the metal layer, the bottom of the metal pattern remains so thin that the metal pattern is embedded in the resin, due to factors such as etching failure. There may be a so-called root residue in which a part of the roughened layer remains, or a foreign substance such as a resin or metal that exists at the interface between the resin substrate and the metal layer may remain. Furthermore, foreign matter may adhere from the outside after pattern formation. In addition, due to residual etching residues and chemicals that cannot be confirmed immediately after etching, or in subsequent plating processes, new foreign matters such as abnormal precipitation may be generated using the foreign matter as a nucleus. Since these foreign matters cause defects such as a decrease in insulation reliability and a short circuit, it is necessary to inspect the surface state and determine and select those having foreign matters in the space as defective products. On the other hand, these foreign substances exist not only between the metal patterns but also on the metal patterns. Similarly, there is a possibility of adverse effects on the subsequent processes such as a decrease in insulation reliability, mounting defects, and appearance defects. Those having abnormalities, i.e., foreign matter, discoloration, or deformation, need to be inspected, determined as defective, and selected.

  As a method of inspecting the surface state of the metal pattern forming resin substrate, there is a method of inspecting the surface state by irradiating the metal pattern forming resin substrate with visible light and detecting the reflected light. Can be observed relatively clearly.

  However, regarding the detection of foreign matter on the resin surface, the surface state of the foreign matter is often not smooth, is not parallel to the surface of the metal layer, the surface is rough and less glossy, and the reflected light is clear. May not be detected.

  In addition, in order to increase the adhesion between the resin substrate and the metal layer, when the metal layer is formed by laminating the metal foil on the resin substrate, a metal foil having a roughened joint surface with the resin substrate is used. In many cases. When a metal layer is formed using such a roughened metal foil, the roughened surface of the metal foil is transferred to the surface of the resin substrate, resulting in unevenness. For this reason, the surface reflection of the resin substrate is also scattered and becomes indistinct by detection by reflected light, so that there is a tendency for the foreign substance and the resin substrate to be more difficult to distinguish.

  In recent years, in order to improve the formation of ultra-high-definition patterns and high-frequency signal transmission characteristics, a metal pattern forming resin in which a so-called low profile metal foil in which a roughened layer is not formed or an extremely weak roughened layer is formed is laminated. A so-called metallized type metal pattern forming resin substrate is also manufactured in which a very thin metal layer is formed on a substrate or a resin substrate by sputtering or the like, and then a conductive metal layer is formed by electrolytic metal plating if necessary. In such a metal pattern forming resin substrate, since the surface of the resin substrate is very smooth, the residue and the resin substrate can be clearly distinguished, but there are components having gloss such as a metal layer on the back surface side. In this case, since the constituents on the back side can be clearly seen, it is difficult to distinguish from the residues on the front side.

  Further, there is a method of observing a metal pattern or a foreign substance between patterns by irradiating light from the back side of the metal pattern forming resin substrate and detecting transmitted light.

  However, in the method of detecting transmitted light, a double-sided substrate having metal patterns on both sides of the resin substrate, a multilayer substrate in which metal pattern-formed resin substrates are laminated, and a shielding layer such as a shield material on the back side are provided. In the case of the formed metal pattern forming resin substrate, detection by transmitted light cannot be performed, the range of use is limited, and the versatility is lacking.

  Further, Patent Documents 1 and 2 listed below disclose a method for inspecting a metal pattern by irradiating a metal pattern forming resin substrate with excitation light to cause the resin substrate to exhibit fluorescence and detecting a light emission amount or a light emission state of the resin substrate. It is disclosed.

JP-A-3-2258 Japanese Patent Laid-Open No. 5-9309

  However, as described in Patent Documents 1 and 2, the method of detecting the light emission amount and the light emission state of the resin substrate by irradiating the resin light with the excitation light on the metal pattern forming resin substrate and detecting the light emission amount and the light emission state of the resin substrate. The surface condition could not be observed, and the abnormality on the metal pattern could not be inspected. For this reason, in order to inspect the surface state of the metal pattern, it is necessary to take measures such as separately irradiating visible light to detect a reflected image, and there is a problem that the inspection process is increased. In addition, since the light emission inside the resin substrate is also detected, it is sometimes difficult to detect the inside of the substrate and even the lower layer components, and to distinguish the foreign material on the resin surface that is originally desired to be distinguished. Further, the observed image tends to be unclear due to the influence of the light emitted from the resin substrate due to interference with reflected light or scattered light of excitation light. For this reason, for example, when the metal pattern is made finer, the presence / absence of foreign matter cannot be accurately determined, and the manufacturing conditions where no defective product without foreign matter is generated cannot be examined.

  Accordingly, an object of the present invention is to provide a method for inspecting a surface of a metal pattern forming resin substrate, which can simultaneously observe a resin surface and a metal pattern surface between metal patterns, and can accurately determine a defective product, and metal pattern formation It is providing the manufacturing method of a resin substrate.

  In order to achieve the above object, the method for inspecting a surface of a metal pattern-formed resin substrate according to the present invention comprises: patterning a metal layer on a resin substrate made of a resin material that emits fluorescence or phosphorescence when irradiated with excitation light. A method for inspecting a surface of a metal pattern forming resin substrate, wherein the excitation light and visible light are simultaneously irradiated onto the metal pattern forming resin substrate, and light emitted from the resin surface of the metal pattern forming resin substrate and the metal pattern are reflected. The visible light is detected by a detection system that does not have sensitivity to the excitation light but has sensitivity to the fluorescence or phosphorescence and visible light.

According to the surface inspection method for a metal pattern forming resin substrate of the present invention, the resin substrate absorbs the excitation light and emits light by irradiating the metal pattern forming resin substrate with the excitation light. Therefore, even if the surface of the resin substrate has unevenness or the inclination of the object to be measured, it is not easily affected, and a substantially uniform bright image can be obtained at the exposed portion of the resin substrate. In addition, when the resin substrate between the metal patterns is exposed and there is a skirt residue, root residue, or etching residue of the metal pattern, regardless of the surface shape or visible light transmittance of the residue or foreign matter, Since it becomes a dark image with respect to light emission, it can be observed as a visible light reflection image, and can be clearly discriminated from a substantially uniform bright image of a portion where the resin substrate is exposed. Even when the foreign material is transparent and transmits excitation light or visible light, the light emitted from the resin substrate below the foreign material is refracted by the foreign material to cause directionality, so it is clearly different from the portion where the resin substrate is exposed. An image can be observed.
Moreover, since visible light is irradiated simultaneously with excitation light, visible light reflects on the surface of a metal pattern, and the reflection image of a metal pattern is obtained. Many of the abnormalities on the metal pattern are dark images because the reflection of the metal is blocked, but since the reflected images are observed, an image corresponding to the abnormal state can be observed.
In addition, by simultaneously irradiating the metal pattern forming resin substrate with excitation light and visible light, the light emitted from the resin surface of the metal pattern forming resin substrate and the visible light reflected by the metal pattern are reflected in the reflected light or scattering of the excitation light. In the present invention, the detection system has no sensitivity to excitation light, and is sensitive to fluorescence or phosphorescence, and visible light. The surface state of the resin substrate can be inspected from the light emitted from the resin surface of the metal pattern-formed resin substrate, and the surface state of the metal pattern can be inspected from the reflected image of visible light reflected by the metal pattern.
As described above, in the present invention, the surface state of the resin substrate and the surface state of the metal pattern can be inspected at the same time, and the resin and metal surface states of the metal pattern forming resin substrate can be inspected with high accuracy and with a small number of inspection steps. In addition, it is possible to easily and accurately inspect whether or not normal metal patterns are formed, and whether there are foreign objects or abnormalities remaining on the resin surface or metal pattern surface between metal patterns. Can be done well.

  In the method for inspecting the surface of a metal pattern-forming resin substrate according to the present invention, the foreign matter remaining on the resin surface between the metal patterns of the metal pattern-forming resin substrate is detected by the fluorescence or phosphorescence, and the metal of the metal pattern is detected by the visible light. It is preferable to detect surface abnormalities. If foreign matter remains on the resin surface, it may cause a failure such as a decrease in insulation reliability or a short circuit. In addition, abnormalities (such as residual foreign matter, discoloration, and deformation) on the metal pattern may similarly adversely affect subsequent processes such as a decrease in insulation reliability, mounting defects, and appearance defects. Therefore, it is possible to reduce the occurrence of product defects in the final product by detecting the presence or absence of these foreign matters or abnormalities, and determining and selecting those having foreign matters or abnormalities as defective products.

  In the method for inspecting a surface of a metal pattern forming resin substrate according to the present invention, it is preferable that the detection system includes a filter having a low transmittance for the excitation light and a high transmittance for the fluorescence or phosphorescence and visible light.

  The method for inspecting the surface of a metal pattern-forming resin substrate according to the present invention is such that the metal pattern-forming resin substrate has the metal pattern on both surfaces of the resin substrate, and the surface side on which the excitation light and the visible light are to be inspected. It is preferable to irradiate from.

  In the metal pattern forming resin substrate surface inspection method of the present invention, the metal pattern forming resin substrate is preferably a circuit board having metal wiring formed by patterning a metal layer.

  In the method for inspecting a surface of a metal pattern-formed resin substrate according to the present invention, the metal pattern-formed resin substrate is preferably a substrate obtained by removing a metal from a laminate of a metal and a resin base material by etching.

  In the method for inspecting the surface of a metal pattern forming resin substrate according to the present invention, the resin substrate is made of one selected from aromatic polyimide, polyurethane containing an imide group, aromatic polyamide, and polyamideimide, and the excitation light has a wavelength. The light is preferably 430 nm or less.

  In the method for inspecting a surface of a metal pattern-formed resin substrate according to the present invention, the arithmetic average roughness Ra of the surface portion where the resin substrate is exposed is preferably more than 0.1 μm or less than 0.1 μm.

  When the arithmetic average roughness Ra is large, that is, when the resin surface is rough, the roughened surface of the metal foil is transferred to the resin surface when the metal layer is formed by laminating the roughened metal foil or the like on the resin substrate. However, it is generally used to increase the adhesion between the resin substrate and the metal layer. However, when the arithmetic average roughness Ra of the portion where the resin substrate is exposed exceeds 0.1 μm, the surface reflection of the resin substrate is significantly scattered, and the detection by the reflected light is reflected in the reflected light even if no foreign matter is present. Because the density becomes dark and unclear, it tends to be more difficult to distinguish between the foreign material and the resin substrate. Also, since the amount of reflected light itself becomes darker, it is difficult to identify the foreign material and discolored metal residue. However, according to the method of the present invention, by irradiating the metal pattern forming resin substrate with excitation light, light is emitted in the vicinity of the surface of the resin substrate, and light emission of the resin substrate is not directional, so the resin substrate is exposed. Such a portion becomes a substantially uniform bright image and is hardly affected by the surface irregularities of the resin substrate. Furthermore, since visible light is also irradiated simultaneously, any abnormality on the metal pattern can be clearly identified.

  It is also effective when the arithmetic average height Ra of the exposed substrate surface of the metal pattern-formed resin substrate is 0.1 μm or less. For example, a laminated plate having a small Ra, that is, a flat resin surface is not roughened or A so-called metallized type laminate that forms a metal layer by laminating a so-called low-profile metal foil, which is manufactured with extremely low roughening, on a resin substrate, or forms a metal layer on the resin surface by sputtering or electrolytic metal plating. In recent years, it is often used for the production of wiring boards with high definition and high-speed transmission wiring boards. However, if the surface roughness Ra of the exposed surface of the resin substrate at the bonding surface between the metal pattern and the resin substrate is 0.1 μm or less, the inside and the back side of the resin substrate can be clearly observed in the surface inspection by irradiation with reflected light. For this reason, it was impossible to distinguish the image from the foreign matter on the resin surface by overlapping the reflection image of the metal layer or foreign matter existing on the inside or lower layer of the substrate, particularly the metal layer on the back side, but according to the method of the present invention. For example, by irradiating the metal pattern forming resin substrate with excitation light, light is emitted in the vicinity of the front surface of the resin substrate, so that it is not affected by components or foreign matters on the resin substrate or on the back side, particularly metal layers. . For this reason, even when the surface roughness Ra of the part where the resin substrate is exposed at the joint surface between the metal pattern and the resin substrate is 0.1 μm or less, the inspection can be performed particularly effectively. Furthermore, since visible light is also irradiated simultaneously, any abnormality on the metal pattern can be clearly identified.

  In the surface inspection method for a metal pattern forming resin substrate according to the present invention, the intensity of visible light applied to the metal pattern forming resin substrate is 0.0001 to 1% of the intensity of excitation light applied to the metal pattern forming resin substrate. It is preferable to do. According to this aspect, the surface state of the resin and metal can be detected with higher accuracy.

  In the method for inspecting a surface of a metal pattern forming resin substrate according to the present invention, it is preferable that visible light and excitation light irradiated on the metal pattern forming resin substrate are emitted from the same light source.

  Moreover, the manufacturing method of the metal pattern formation resin board | substrate of this invention test | inspects the resin and metal surface of a metal pattern formation resin board | substrate by the said method, It is characterized by removing a defective product.

  According to the present invention, excitation light and visible light are simultaneously irradiated onto the metal pattern forming resin substrate, and light emitted from the resin surface of the metal pattern forming resin substrate and visible light reflected by the metal pattern have sensitivity to the excitation light. First, by detecting with a detection system having sensitivity to fluorescence or phosphorescence and visible light, the surface state of the resin substrate and the surface state of the metal pattern can be inspected at the same time. The surface condition of resin and metal can be inspected. Furthermore, it is possible to easily and accurately inspect whether or not a normal metal pattern is formed and whether or not there is a foreign matter or abnormality remaining on the resin surface or metal pattern surface between metal patterns. For this reason, since defective products can be discriminated efficiently, a metal pattern forming resin substrate with extremely few defective products can be manufactured with high productivity.

It is a schematic block diagram of the surface inspection method of the metal pattern formation resin substrate of this invention. 2 is a camera image of a circuit board obtained by the method of Example 1. FIG. 2 is a camera image of a circuit board obtained by the method of Comparative Example 1. It is a camera image of the circuit board obtained by the method of Comparative Example 2.

  First, a metal pattern forming resin substrate to be inspected according to the present invention will be described.

  The metal pattern forming resin substrate is not particularly limited as long as the metal layer is patterned on the resin substrate. The single-sided substrate having the metal pattern on one side of the resin substrate, the double-sided substrate having the metal pattern on both sides of the resin substrate Any of the multilayer substrates formed by laminating a plurality of these can be preferably used.

  In particular, the method for inspecting the surface of a metal pattern-formed resin substrate according to the present invention is particularly effective in the surface inspection of those having metal patterns on both surfaces of a resin substrate represented by a double-sided wiring board or a multilayer wiring board. That is, in the present invention, the metal pattern-formed resin substrate is irradiated with excitation light, and fluorescence or phosphorescence emitted from the vicinity of the surface of the resin substrate is detected. At this time, the excitation light preferably has a wavelength that has a low transmittance to the resin substrate and is absorbed by the resin material surface layer. In this case, most of the excitation light is absorbed by the surface layer and emission from the resin substrate is suppressed. Then, light is emitted from the resin substrate surface. For this reason, it is possible to accurately observe whether or not foreign matter is present on the resin surface between the metal patterns to be inspected without being affected by the foreign matter or metal pattern present on the back side of the resin substrate.

  As a preferable example of such a metal pattern forming resin substrate, a circuit substrate having a metal wiring formed by patterning a metal layer on the surface of the resin substrate can be cited.

  The resin material of the resin substrate used for the metal pattern forming resin substrate emits fluorescence or phosphorescence from the surface when irradiated with excitation light (preferably light with a wavelength of 430 nm or less, more preferably ultraviolet light with a wavelength of 400 nm or less). If it is a thing, there will be no limitation in particular. Among such resin materials, those having excellent physical properties such as insulation, heat resistance and strength can be preferably used for circuit boards. For example, polyimide, polyurethane containing imide group, wholly aromatic polyester, polyethylene terephthalate, polyethylene naphthalate, polyetherketone, polyetheretherketone, polysulfone, polyethersulfone, polyamide, polyamideimide, polyetherimide, polycarbonate, polyphenylene ether , Polyphenylene sulfide, polymethylpentene, polyarylate, epoxy resin, phenol resin, polytetrafluoroethylene, fluorinated ethylene propylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, ethylene tetrafluoroethylene copolymer, Examples thereof include polyvinylidene fluoride and polyvinyl fluoride. Among these, the absorption of excitation light is large, and when irradiated with excitation light, it emits fluorescence or phosphorescence, and further, it has excellent properties such as insulation, strength, heat resistance, etc. Preferred resin materials include polyurethane, wholly aromatic polyester, polyethylene naphthalate, polyether ketone, polyether ether ketone, polyether sulfone, aromatic polyamide, polyamide imide, polyether imide, polycarbonate, epoxy resin, and phenol resin. Used. Furthermore, resins having aromatic rings, typically aromatic polyimides, polyurethanes containing imide groups, aromatic polyamides, and polyamideimides, have strong absorption for light having a short wavelength of 430 nm or less, particularly ultraviolet light having a wavelength of 400 nm or less. By irradiating the surface with these lights, the constituent resin of the substrate itself emits strong fluorescence or phosphorescence from the surface layer, and there is no need to consider deterioration of characteristics due to mixing of additives for light emission and absorption. More preferably used. Among them, the aromatic polyimide is particularly preferable because it is thin but has sufficient strength, is strong against bending, and is absorbed by the surface layer of the resin material when irradiated with excitation light, and emits particularly strong fluorescence from the surface.

  As an aromatic polyimide, for example, pyromellitic dianhydride, biphenyl tetracarboxylic dianhydride, oxydiphthalic dianhydride, diphenyl sulfone tetracarboxylic dianhydride, bis ( Dicarboxyphenyl) sulfide dianhydride, 2,2-bis (dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, benzophenonetetracarboxylic dianhydride, bis (3 , 4-Dicarboxyphenyl) methane dianhydride, 2,2-bis (dicarboxyphenyl) propane dianhydride, p-phenylenebis (trimellitic acid monoester anhydride), p-biphenylenebis (trimellitic acid) Monoester anhydride), terphenyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, , 3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (dicarboxyphenoxy) benzene dianhydride, 1,4-bis (dicarboxyphenoxy) biphenyl dianhydride, 2, One or more tetracarboxylic acids selected from 2-bis [(dicarboxyphenoxy) phenyl] propane dianhydride, naphthalenetetracarboxylic dianhydride, (2,2-hexafluoroisopropylidene) diphthalic dianhydride Examples of dianhydrides and diamines include diamine diamine, tolylenediamine, diaminobenzoic acid and other benzene nucleus diamines, diaminodiphenyl ether, diaminodiphenylmethane, dimethyldiaminobiphenyl, bis (trifluoromethyl) diaminobiphenyl, dimethyldiamino Diphenylme , Dicarboxydiaminodiphenylmethane, tetramethyldiaminodiphenylmethane, diaminodiphenyl sulfide, diaminobenzanilide, dichlorobenzidine, dimethylbenzidine, dimethoxybenzidine, diaminodiphenylsulfone, diaminobenzophenone, diaminodimethoxybenzophenone, 2,2-bis (aminophenyl) propane , Bis (aminophenyl) -1,1,1,3,3,3-hexafluoropropane, diaminodiphenyl sulfoxide and other benzene nuclei, two diamines, bis (aminophenyl) benzene, bis (aminophenoxy) benzene, bis ( Aminophenoxy) trifluoromethylbenzene, diaminophenylphenoxybenzophenone, diaminodiphenylphenoxybenzophenone, bis ( Aminophenyl sulfide) benzene, bis (aminophenylsulfide) benzene, bis (aminophenylsulfone) benzene, bis (2-aminophenylisopropyl) benzene, and other benzene nucleus three diamines, bis (aminophenoxy) biphenyl, bis (amino Phenoxy) phenyl ether, bis (aminophenoxy) phenyl ketone, bis (aminophenoxy) phenyl sulfide, bis (aminophenoxy) phenylsulfone, 2,2-bis (aminophenoxy) phenylpropane, 2,2-bis (aminophenoxy) A resin composed of one or a combination of two or more diamines selected from four diamines such as phenyl-1,1,1,3,3,3-hexafluoropropane, and in particular tetracarboxylic acid As water, pyromellitic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, p-phenylenediamine as diamine, 4, A composition containing 4′-diaminodiphenyl ether and 1,3-bis (4-aminophenyl) benzene is preferably exemplified. Among them, pyromellitic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, p-phenylenediamine as diamine, 4,4 An aromatic polyimide comprising a combination of '-diaminodiphenyl ether and 1,3-bis (4-aminophenyl) benzene is particularly preferably used in the present invention because it emits particularly intense light and can accurately inspect the surface state of the metal pattern forming resin substrate. be able to.

  In the metal pattern forming resin substrate, the metal material to be laminated on the resin substrate is not particularly limited, and metals such as copper, nickel, chromium, manganese, aluminum, iron, molybdenum, cobalt, tungsten, vanadium, titanium, tantalum, silicon, etc. Or an alloy thereof, or a metal compound such as an oxide or a metal carbide of these metals, and copper, which has a low electrical resistance and is easily available, is preferably used.

  In order to form a metal layer on the resin substrate, for example, a method of forming a metal layer by pressing a metal foil on the surface of the resin substrate, or after forming a very thin metal layer on the surface of the resin substrate by sputtering or the like, Examples include a method of forming a metal layer by performing electrolytic metal plating as necessary. In addition, when a metal layer is formed on a resin substrate using a metal foil having a roughened layer having an arithmetic average roughness Ra exceeding 0.1 μm, stable adhesion between the resin substrate and the metal layer can be obtained. On the other hand, the roughened layer is transferred to the surface of the resin substrate to form an uneven shape. For this reason, when forming the metal pattern by removing the metal layer, the metal tends to remain in the recesses on the surface of the resin substrate. When the metal pattern is highly refined, the pattern pitch is particularly 100 μm or less, preferably 10 to 10 μm. In the case of 100 μm, careful inspection of residual foreign matter between patterns is important. Further, when the metal pattern is made ultra-high definition, particularly when the pattern pitch is 40 μm or less, the arithmetic average roughness Ra of the joint surface between the metal wiring and the resin substrate is preferably 0.1 μm or less. If the arithmetic average roughness Ra is a flat joint surface of 0.1 μm or less, the maximum unevenness can be kept low, and the root residue between the wirings can be prevented. As described above, the excitation light has a low transmittance through the resin substrate, and the light emission of the resin substrate due to the excitation light irradiation occurs almost uniformly near the surface of the resin substrate. According to the method of the present invention, even if the arithmetic average roughness Ra of the exposed portion of the resin substrate from which the metal layer on which the roughened layer is formed is removed exceeds 0.1 μm, scattering due to surface irregularities In addition, when the metal layer and the resin substrate have a flat joint surface, and the arithmetic average roughness Ra of the portion where the resin layer is exposed by removing the metal layer is 0.1 μm or less Even so, it is possible to accurately observe whether or not a foreign substance is present on the resin surface between the metal patterns to be inspected without being affected by reflection from the back surface or the components in the substrate.

  The method for forming the metal pattern on the resin substrate is not particularly limited and can be formed using a conventionally known method. For example, a subtractive method, a semi-additive method, etc. are mentioned.

  In the subtractive method, a metal layer having a predetermined thickness is formed on a resin substrate, the surface of the metal layer is washed, a photoresist layer is formed, exposed and developed to form an etching mask, and an etching solution such as iron chloride is applied. The metal pattern forming resin substrate can be manufactured by removing the metal between the patterns by dipping or spraying and removing the unnecessary photoresist.

  In the semi-additive method, a very thin metal layer (thin metal layer) of about 0.2 to 3 μm is formed by laminating a thin metal foil on the surface of the resin substrate or performing sputtering or the like. Then, after cleaning the surface of the thin metal layer, a thick photoresist layer is formed, and exposed and developed to form a pattern mold. Then, after depositing the metal that becomes the metal wiring pattern by electrolytic plating on the part where the photoresist is not formed using the thin metal layer as the power feeding layer, the photoresist is removed, and the metal wiring pattern is removed by immersion or spraying in the etching solution. The metal pattern forming resin substrate can be manufactured by removing the metal thin layer.

  In addition, when the metal pattern forming resin substrate manufactured in this way is used as, for example, a circuit board, the metal pattern portion is made of gold or tin to prevent oxidation or to join with a component to be mounted as necessary. Electrode plating may be performed.

  Moreover, the metal pattern formation resin substrate may be independent by itself, and may be formed on the structure used as another foundation. In addition, it is preferable that the metal and resin surfaces are exposed from the clearness of the image, but a protective layer or the like may be formed in a range that does not affect the inspection. There is no need to emit fluorescence or phosphorescence in response to excitation light irradiation and to have no absorption or scattering that disturbs the image.

  Next, regarding the surface inspection method of the metal pattern forming resin substrate of the present invention, a double-sided substrate in which metal patterns 3 and 4 are formed on both surfaces of the resin substrate 2 was used as the metal pattern forming resin substrate 1 with reference to FIG. A case will be described as an example. In FIG. 1, 11a is an excitation light source, 11b is a visible light source, 12 is a light guide, 14 is a detection means, 15 is an excitation light removing filter, 16 is a condensing lens, and 21 is a support base.

  First, the metal pattern forming resin substrate 1 is arranged on the support base 21 so that the inspection surface becomes the upper surface.

  Next, the light from the light source is transmitted through the light guide 12 and emitted from the tip of the light guide 12, and the excitation light a1 and the visible light a2 are simultaneously measured at the measurement site of the metal pattern forming resin substrate 1 (in FIG. (Frame A region) is irradiated.

  In order to irradiate the excitation light a1 and the visible light a2 at the same time, for example, as shown in FIG. 1, an excitation light source 11a and a visible light source 11b are provided, and a light guide 12 is transmitted from each light source, and each light guide is transmitted. And the like.

  There is no limitation in particular as the excitation light source 11a. Any one of a single wavelength light source, a plurality of wavelength light sources, and a continuous wavelength spectrum light source can be used as long as it has a wavelength that is absorbed by the resin material surface layer, but it is 430 nm or less that is easily absorbed by the resin material surface layer. A light source that can emit ultraviolet light, particularly ultraviolet light of 400 nm or less, is preferable, and examples thereof include a high-pressure mercury lamp, an ultraviolet light-emitting diode, a black light, a Xe-Hg lamp, and a metal halide lamp. Here, when a light source having a plurality of wavelengths or a continuous wavelength spectrum light source is used and includes a wavelength that is not absorbed by the resin material surface layer in addition to a wavelength that is absorbed by the resin material surface layer, this contributes to the emission of fluorescence or phosphorescence. In this case, the light emitted from the light source is transmitted through the wavelength absorbed by the resin material surface layer and absorbed by the resin material surface layer. It is more preferable that only the wavelength absorbed by the resin material surface layer is passed through a filter that cuts off wavelengths that are not used as excitation light, so that a clearer luminescent image can be obtained. Here, various types of filters can be used, such as an absorption type, a reflection type, or a necessary wavelength bent through 45 degrees, for example. However, it is only necessary to guide light having a necessary wavelength to a necessary position. . Further, in order to increase the excitation light intensity, the light may be condensed on the observation site by a condenser lens. In this embodiment, a filter 13 that selectively increases the transmittance of the excitation light a1 is attached to the tip of the light guide 12 extending from the excitation light source 11a, and the excitation light a1 having a specific wavelength is measured by the condenser lens 16. It is configured so that it can be focused and irradiated with high intensity.

  The visible light source 11b is not particularly limited. Any light source capable of observing the reflection image of the metal pattern can be used, and any of a single wavelength light source, a plurality of wavelength light sources, and a continuous wavelength spectrum light source can be used. For example, fluorescent lamps, halogen lamps, tungsten lamps, LED light sources, Xe lamps and the like can be mentioned.

  In addition, when an irradiation light source is a several wavelength light source and a continuous wavelength spectrum light source, it is possible to use as a light source which has both components of excitation light and visible light. High-pressure mercury lamps, Xe-Hg lamps, metal halide lamps, Xe lamps, etc. have a continuous spectrum (white light) of ultraviolet light components and visible light components suitable for excitation light, and excitation light and visible light with a single light source. Can be irradiated. Here, when directly irradiating from these light sources, since visible light tends to be too strong, it is preferable to attenuate the visible light with a wavelength filter or the like and irradiate the metal pattern forming resin substrate.

  As the excitation light a1 applied to the metal pattern forming resin substrate, light having a wavelength that is absorbed by the surface layer of the resin material is preferably used, using light having a short wavelength that is highly absorbed by the resin material constituting the resin substrate of the metal pattern forming resin substrate. . Since most of the excitation light is absorbed by the surface layer of the resin material, light emission from the inside of the resin substrate is suppressed and light is emitted only from the vicinity of the resin substrate surface. Thus, the exposed portion of the resin substrate can be observed as a clearer image, and the surface state of the metal pattern-formed resin substrate can be detected more accurately. The resin surface layer that emits light upon absorption of excitation light is not particularly limited as long as it can be treated as a substantially surface layer without reaching the back surface or internal components because it varies depending on the thickness and configuration of the substrate, but preferably within 10 μm from the resin surface, More preferably, within 5 μm, particularly preferably within 3 μm, when most of the excitation light is absorbed, it is difficult to be affected by the components inside the substrate and the underlying components. The amount of excitation light absorbed by the surface layer should not be substantially affected by the inside or the back surface, but preferably 50% of the excitation light is emitted, and more preferably 80% or more of the excitation light is absorbed by the surface layer. It is clearer and particularly preferred. Specifically, the excitation light is preferably light having a wavelength of 430 nm or less, and particularly preferably ultraviolet light having a wavelength of 400 nm or less.

  The intensity of the visible light a2 applied to the metal pattern forming resin substrate 1 may be adjusted so that a fluorescent or phosphorescent image emitted from the resin substrate and a visible light reflection image of the metal pattern can be easily observed simultaneously. Although visible light is also reflected from the surface of the resin substrate, it is weaker than the reflection of the surface of the metal pattern. Therefore, if it is easy to observe at the same time as described above, the light emission image is dominant on the surface of the resin substrate. Therefore, in the above adjustment, it is more preferable to adjust so that the reflection image on the surface of the metal pattern is darker than the fluorescence or phosphorescence image emitted from the resin substrate. If the intensity of visible light is too strong, the effect of observation due to light emission from the resin substrate surface is reduced due to the reflection of visible light from the resin substrate surface and back surface, whereas if the intensity of visible light is too weak, metal Identification of abnormal parts on the pattern is unclear. Since the ratio of the intensity of visible light and excitation light varies depending on the luminous efficiency of the resin material used for the substrate, the surface state of the metal pattern, and the reflectance depending on the irradiation method, the intensity may be adjusted to an intensity suitable for the substrate configuration. The intensity of the excitation light a1 applied to the metal pattern forming resin substrate is preferably 0.0001 to 1%, more preferably 0.001 to 1%. When the intensity of the visible light a2 applied to the metal pattern forming resin substrate 1 is less than 0.0001% of the intensity of the excitation light a1 applied to the metal pattern forming resin substrate 1, the reflected light image of the visible light a2 is reflected on the metal pattern. It tends to be difficult to observe. If it exceeds 1%, the reflected image of visible light a2 becomes dominant, and it tends to be difficult to observe the resin substrate surface based on the light emission image of the resin substrate by excitation light irradiation.

  The excitation light a1 and the visible light a2 are preferably irradiated from the surface side to be inspected of the metal pattern forming resin substrate. Any irradiation method can be preferably used as long as the irradiation is performed from the surface side to be inspected. If the excitation light is irradiated from the surface, it hardly depends on the irradiation angle, but the visible image may change greatly depending on the relationship between the surface shape of the substrate and the irradiation angle. Also good. For example, the metal pattern forming resin substrate may be irradiated obliquely from above, or may be irradiated from directly above through a magnifying lens. In this embodiment, the excitation light a <b> 1 and the visible light a <b> 2 are applied to the measurement site from obliquely above the metal pattern forming resin substrate 1. In addition, since the excitation light a1 has low transparency and is easily absorbed by the resin substrate, fluorescence or phosphorescence cannot be generated from the surface side to be inspected when the excitation light a1 is irradiated from the side surface side or the back surface side. In other cases, the amount of emitted light is weak and accurate surface inspection cannot be performed. Furthermore, even if visible light a2 is irradiated from the side surface side or the back surface side, a reflection image of the metal pattern on the surface side to be inspected cannot be obtained, and the surface state of the metal pattern cannot be inspected.

  When the metal pattern forming resin substrate 1 is irradiated with excitation light a1 and visible light a2 at the same time, the excitation light a1 is absorbed by the resin substrate, and fluorescence or phosphorescence is emitted from the surface of the resin substrate 2. Further, a part of the excitation light a 1 and the visible light a 2 are reflected or scattered on the surface of the resin substrate 2 or the surface of the metal pattern 3. That is, the light b1 generated from the metal pattern forming resin substrate 1 by simultaneously irradiating the metal pattern forming resin substrate 1 with the excitation light a1 and the visible light a2 includes fluorescence emitted when the resin substrate 2 absorbs the excitation light, or Phosphorescence, excitation light reflected or scattered on the surfaces of the resin substrate 2 and the metal pattern 3, and reflection of visible light on the surface of the metal pattern 3 are mixed. For this reason, in the image observed by detecting such light b1, the image of the interface between the resin substrate and the metal layer tends to become unclear due to the interaction of the components of each light. Since the excitation light intensity is stronger than the visible light intensity, if the reflected light or scattered light of the excitation light is detected, there is a possibility that a light emission image or a visible light reflected light image that is an observation purpose is buried.

  Therefore, in the present invention, the light b1 emitted from the metal pattern forming resin substrate 1 is detected by a detection system that does not have sensitivity to excitation light but has sensitivity to fluorescence or phosphorescence and visible light.

  In the present invention, “detection with a detection system having no sensitivity to excitation light, fluorescence or phosphorescence, and sensitivity to visible light” means that the sensitivity of the detection system to excitation light is fluorescence or phosphorescence, and By detecting using a detection system that can detect light emission and visible light by substantially excluding the influence of excitation light. is there. In addition, the wavelength range of fluorescence or phosphorescence is often visible light, and in this case, detection is performed using a detection system that can substantially detect the visible light without the influence of excitation light. When the final detection means of the detection system is the naked eye, the light emission must be visible light. Therefore, when the excitation light contains a visible light component, it is necessary not to disturb the observation by the light emission. It is preferable that detection is performed by adjusting the sensitivity of the entire detection system with an optical system such as a wavelength filter as necessary so that the intensity of the visible light component of the excitation light is 10% or less of the intensity of the visible light component of the emitted light. When the final detection means of the detection system is to convert it into an electrical signal, the sensitivity to the excitation light is preferably 1% or less, more preferably 0.5% or less of the sensitivity to the emission. This is preferable because a clear emission image can be obtained while suppressing the influence of fogging.

  As the detection system, a camera having the naked eye or an image sensor can be used, and the detection system is particularly limited as long as it is composed of a system with low sensitivity to excitation light, high fluorescence or phosphorescence wavelength, and high sensitivity to visible light. However, since CCD and CMOS sensors used for the naked eye and image sensors generally have sensitivity in a wide wavelength range, in this case, the transmittance for the wavelength range of excitation light is low, and fluorescence or phosphorescence, Further, it may be detected through a filter having a high visible light transmittance. Here again, a wide variety of types of filters can be used as described above, and the term “transmittance” here is used to mean wavelength selection for a required optical path, and is simply a transmittance for straight light travel. It is not limited to. Here, the sensitivity of the detection system is the sensitivity of the entire system including the optical system such as the sensor, the filter, and the lens. When the light emitted from the measurement target is detected by the sensor and determined, It is important that it can be determined only by fluorescence or phosphorescence.

  In this embodiment, the light receiving unit 14 detects light b2 from which excitation light is removed or reduced by passing through the excitation light removal filter 15 having low transmittance of excitation light and high transmittance of fluorescence or phosphorescence and visible light. Then, the surface inspection of the metal pattern forming resin substrate 1 is performed.

  As the excitation light removal filter 15, it is preferable to use a filter having a transmittance of 0 to 0.5% for excitation light and a transmittance of 50 to 100% for emitted light and visible light composed of fluorescence or phosphorescence. It is more preferable to use a light transmittance of 0 to 0.35% and a transmittance of 70 to 100% of the emitted light and visible light.

  The image obtained by detecting the light b2 from which the excitation light has been reduced or removed through the excitation light removal filter 15 in this way is not affected by the reflected light or scattered light of the excitation light, and is a portion where the resin substrate is exposed. Is observed as a bright image with high contrast, very clear and almost homogeneous. Moreover, the part in which the metal pattern 3 exists is obtained as a reflected image of visible light, and the surface state of the metal pattern 3 can be observed by observing the reflected image. In addition, the bottom of the metal pattern, the root residue, and etching residue are often not smooth, and clear reflected light is detected due to the rough surface, low gloss, and irregular shape. It is difficult to observe the light emitted from the resin substrate and is generally observed as a dark image. However, it may be bright because it is a visible light reflection image, but it is clearly different from the light emitted from the resin substrate surface. Can be distinguished from the surroundings. Further, even when the foreign matter is transparent and the foreign matter is transparent and transmits excitation light or visible light, light emitted from the resin substrate 2 below the foreign matter is refracted by the foreign matter to cause directionality. An image clearly different from the exposed part is observed. On the other hand, the abnormality on the metal pattern is often a dark image because the reflection of the metal is blocked, but since it is a natural reflection image, an image corresponding to the abnormal state is naturally obtained.

  Therefore, the uniform bright portion can be recognized as a portion where the resin substrate is exposed, that is, an image between the metal patterns, and an image of the metal pattern can be recognized as a reflected image of visible light. Thereby, the space | interval of a metal pattern and a pattern defect can be determined. In addition, it is possible to determine a local or peculiar dark part or a part with different brightness as a foreign object.

  The light b2 obtained through the excitation light removal filter 15 is received by the detection means 14, and the obtained image is inspected. The inspection by the detection means 14 can be performed by a conventionally known method. For example, the image pattern may be recognized by magnifying with a microscope or a microscope and detected with the naked eye, or may be detected with a camera such as a CCD, processed as necessary, and observed on a display. The image may be recognized by a known image recognition system. Of course, an inspection camera integrated with a magnifying lens can be used, and the image signal can be automatically discriminated by taking it into an AOI system or the like. In addition, in the case of visual inspection by an inspector, it can be easily determined empirically. In the case of automatic inspection by image processing, a normal pattern image is registered and compared, or a CAD drawing is displayed. You may determine based on the pattern produced from data.

  In the method for inspecting a surface of a metal pattern forming resin substrate according to the present invention, since a certain region of the metal pattern forming resin substrate 1 is measured by an image, a wider field of view is better from the viewpoint of inspection efficiency. For example, if the area is 0.1 mm square or more, a plurality of sets of lines / spaces of 40 μm pitch wiring are preferable, and if it is 0.4 mm or more, 10 sets of lines / spaces are more preferable as the inspection. Thus, when the field of view is widened by limiting the magnification, the reflection measurement alone makes it extremely difficult to distinguish the foreign matter between the resin surface scattering and the reflected light on the back surface and the metal pattern, and the effect of the present invention is remarkable. is there.

  Then, in the manufacturing process of the metal pattern forming resin substrate, the surface of the metal pattern forming resin substrate is inspected in this way, and the interval between the metal patterns is narrow, the pattern is defective, or foreign matter is put on the resin surface between the metal patterns. Metal pattern forming resin substrates that have been determined to have or have been determined to have foreign matter or other abnormalities on the surface of the metal pattern are selected as defective products, and removed to remove metals with extremely few defective products. A patterned resin substrate is obtained as the final product.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

(Measuring method)
Method for measuring arithmetic average roughness Ra: Based on JIS B0601 (2001), a length of 30 μm was measured using a confocal laser microscope VK-8500 (manufactured by Keyence Corporation).

Example 1
A 9 μm thick electrolytic copper foil (trade name “USLP”, manufactured by Nippon Electrolytic Co., Ltd.) with a roughened layer formed on one side is a polyimide film (trade name “UPILEX VT”, manufactured by Ube Industries, Ltd.) having a heat-sealing layer. ) Using a metal laminated polyimide film (trade name “Iupicel N”, manufactured by Ube Nitto Kasei Co., Ltd.) laminated so that the roughened layer side is in contact with the polyimide film on both sides, and removing unnecessary copper on both sides in the etching process. A circuit board was obtained by forming a wiring pattern with a pitch of 40 μm on one surface and leaving a part of copper from the other surface. The arithmetic average roughness Ra of the portion where the polyimide was exposed was 0.28 μm. A foreign object was adhered on the substrate to obtain a measurement object.
A filter (blocking visible light by passing 60% or more of ultraviolet light (360 nm) provided at the tip through the light guide from the high-pressure mercury lamp house to the surface to be inspected of the circuit board thus manufactured ( UTVAF-36U (manufactured by Sigma Kogyo Co., Ltd.), white light whose intensity is adjusted through the light guide 12 from the white LED lamp house 11b while condensing and irradiating excitation light consisting of ultraviolet light having a wavelength of 400 nm or less with the lens 16 By irradiating a2, the polyimide wiring board surface was irradiated with excitation light and visible light simultaneously. Here, the intensity of excitation light on the substrate surface was 1.5 W / cm ² , and the intensity of visible light was 0.15 mW / cm ² (the intensity of visible light was 0.001% of the intensity of excitation light). . Then, a filter provided on the surface of the circuit board after the objective lens of the microscope (the transmittance of ultraviolet light having a wavelength of 400 nm or less is 0.1% or less, the transmittance of emitted light having a wavelength of 450 to 700 nm is 85% or more, SCF The excitation light was removed through -42L (manufactured by Sigma Kogyo Co., Ltd.), and the surface state in the range of 0.4 mm square or more of the circuit board was observed as a light emission image and a visible reflection image.
FIG. 2 is a camera image of this embodiment. The portion 301 where the polyimide surface exposed by removing the metal is exposed is bright when fluorescence emission is dominantly observed in response to ultraviolet light, and the metal wiring portion 302 has no fluorescence emission and shows a reflected image of visible light. Has been. Here, the foreign material portion 303 between the wiring patterns is shown dark because the excitation light is blocked and fluorescence emission is not seen, while the foreign material portion 304 on the metal wiring is shown dark because the metal reflection is hindered. . In this way, the foreign matter between the wiring patterns and the foreign matter on the wiring pattern can be clearly identified simultaneously.
Note that a copper foil was present on the entire back surface of the circuit board of the camera image.

(Comparative Example 1)
The surface state of the circuit board was observed in the same manner as in Example 1 except that only the visible light was irradiated to the same part of the circuit board used in Example 1.
FIG. 3 is a camera image of the first comparative example. The portion 401 where the polyimide surface that appears after removing the metal is exposed is shown dark with a small amount of reflected light, and the metal wiring pattern portion 402 shows a reflected image of visible light. Although the foreign matter portion 403 on the metal wiring is darkly shown because the metal reflection is hindered and can be clearly recognized, the foreign matter 404 between the portion where the polyimide surface shown darkly is exposed and the wiring is unclear.

(Comparative Example 2)
The surface state of the circuit board was observed in the same manner as in Example 1 except that only the excitation light composed of ultraviolet light was irradiated to the same portion of the circuit board used in Example 1.
FIG. 4 is a camera image of the second comparative example. The portion 501 where the polyimide surface that appears after removing the metal is exposed is shown bright when fluorescence emission is observed in response to ultraviolet light, and the portion 502 where the metal remains is shown dark without fluorescence emission. The foreign matter portion 504 between the wirings is dark and clearly recognizable because the excitation light is blocked and fluorescence emission is not seen, but the foreign matter 503 on the wiring is dark as well as the normal pattern and thus cannot recognize the foreign matter. It was.

1: Metal pattern forming resin substrate 2: Resin substrate 3, 4: Metal pattern 11a: Excitation light source 11b: Visible light source 12: Light guide 13: Filter 14: Detection means 15: Excitation light removal filter 16: Condensing lens 21: Support Stand

Claims (10)

A method for inspecting a surface of a metal pattern-formed resin substrate obtained by patterning a metal layer on a resin substrate made of a resin material that emits fluorescence or phosphorescence when irradiated with excitation light,
The metal pattern forming resin substrate is simultaneously irradiated with excitation light and visible light having an intensity of 0.0001 to 1% of the excitation light from the surface side to be inspected, from the resin surface of the metal pattern forming resin substrate. the visible light emitted light and the metal pattern is reflected, no sensitivity to the excitation light, the fluorescence or phosphorescence, and detected simultaneously in the same detection system that is sensitive to visible light, said from the fluorescent or phosphorescent A method for inspecting a surface of a metal pattern forming resin substrate , wherein foreign matter remaining on a resin surface between metal patterns of the metal pattern forming resin substrate is detected and an abnormality of the metal surface of the metal pattern is detected from the visible light. . The detection system has a low transmittance for the excitation light, the fluorescence or phosphorescence, and the transmittance for visible light and a high filter, metal patterned resin surface inspection method for a substrate according to claim 1. 3. The metal pattern according to claim 1, wherein the metal pattern forming resin substrate has the metal pattern on both surfaces of the resin substrate, and irradiates the excitation light and the visible light from a surface side to be inspected. Surface inspection method for formed resin substrates. The metal pattern formation resin substrate, a metal pattern forming resin surface inspection method for a substrate according to any one of claims 1 to 3, which is a circuit board having a metal wiring formed by patterning a metal layer. The surface of the metal pattern forming resin substrate according to any one of claims 1 to 4 , wherein the metal pattern forming resin substrate is a substrate obtained by etching a metal from a laminate of a metal and a resin base material. Inspection method. The said resin substrate consists of 1 type chosen from the aromatic polyimide, the polyurethane containing an imide group, aromatic polyamide, and polyamideimide, The said excitation light is light with a wavelength of 430 nm or less, Any one of Claims 1-5 A method for inspecting a surface of a metal pattern-formed resin substrate according to claim 1. The surface inspection method of the metal pattern formation resin substrate as described in any one of Claims 1-6 with which arithmetic mean roughness Ra of the surface part which the said resin substrate exposed exposed exceeds 0.1 micrometer. The surface inspection method for a metal pattern-formed resin substrate according to any one of claims 1 to 6 , wherein the arithmetic average roughness Ra of the surface portion where the resin substrate is exposed is 0.1 µm or less. The visible light and the pumping light provided to the metal pattern formation resin substrate is emitted from the same light source, a metal pattern forming resin surface inspection method for a substrate according to any one of claims 1-8. The method according to any one of claims 1-9, examines the resin and the metal surface of the metal pattern formation resin substrate, a metal pattern forming the resin substrate manufacturing method, characterized in that except for the defective products.