JP5558157B2 - Wiring board - Google Patents

Description

  The present invention relates to a wiring substrate applied to a package for housing a semiconductor element, a high-frequency module substrate, and the like, and more particularly to a wiring substrate that can be suitably used in a high-frequency application that requires various component mounting.

  Conventionally, wiring boards using alumina as a substrate material and tungsten or molybdenum as a conductor layer material have been widely used, and various electronic components such as semiconductor elements, capacitors, and filters are mounted on the surface of the wiring board. Thus, a semiconductor element storage package and a high-frequency module substrate are configured.

  However, when alumina is used as the substrate material, the firing temperature is as high as about 1600 ° C., and therefore it is necessary to use a refractory metal having high resistance as the conductor layer material. In recent years, low-temperature fired substrates that can be fired in the air and can be fired below the melting point of silver with the lowest specific resistance and reduce the conductor loss of high-frequency circuits have been widely developed. In order to reduce body loss, an insulating substrate having a small dielectric loss has been developed (see, for example, Patent Document 1).

  On the other hand, when mounting various electronic components on the wiring board, the image recognition device recognizes the surface conductor layer formed on the surface of the wiring board and the recognition mark formed using the conductor layer material, and aligns them. It is carried out.

  In such a recognition process by the image recognition device, when a surface conductor layer is formed using Ag on a white wiring board, or when a recognition mark is formed using Ag on a white wiring board. Since the difference in color tone and reflectance between the white wiring board and the surface conductor layer or recognition mark made of Ag is small, the image recognition device cannot accurately recognize the position of the surface conductor layer or the recognition mark. There is a problem that a recognition error is likely to occur.

  Therefore, by adding pigment powders such as various transition metal oxides into the wiring board and coloring the wiring board, the difference in color tone and reflectance with the surface conductor layer and the recognition mark formed of Ag is increased, A technique for suppressing a recognition error by an image recognition apparatus is disclosed (for example, see Patent Documents 2 and 3).

  On the other hand, it is obvious that the dielectric loss of the wiring board largely depends on the design of the main crystal phase and the glass phase constituting the wiring board, but in addition, the influence of trace components such as various additives and impurities cannot be ignored. For example, transition metal oxides such as manganese oxide and iron oxide, which are generally used as the above-mentioned pigment powder, greatly increase the dielectric loss of the wiring board, so the content should be reduced as much as possible. Desirable to lower In other words, in order to reduce the dielectric loss of the wiring board, it is desirable that the white wiring board does not contain a transition metal oxide.

  Therefore, conventionally, by coloring only one insulating layer arranged on the surface of the wiring board, the problem of recognition error by the image recognition apparatus is solved, and the increase in dielectric loss is limited to only one insulating layer on the surface. A suppressed technique is disclosed (for example, see Patent Document 4).

JP 2002-53368 A JP-A-9-51150 JP-A-9-169568 JP-A-8-274429

  However, even in the invention described in Patent Document 4, an increase in dielectric loss in one insulating layer on the surface is unavoidable, and the influence is so large that it cannot be ignored with the recent increase in frequency and integration of wiring boards. It has become to.

  That is, with the recent trend toward higher frequency and higher integration of wiring boards, high frequency signals often propagate through the inner conductor layer formed facing one insulating layer on the surface. An internal conductor formed facing the insulating layer on the surface because pigment powder such as iron oxide and cobalt oxide is uniformly present on the entire insulating layer and the dielectric loss of the entire insulating layer on the surface is large. There has been a problem that attenuation when a high-frequency signal propagates through the layer becomes large.

  It is an object of the present invention to provide a wiring board that can suppress recognition errors caused by an image recognition device and can suppress an increase in dielectric loss to a minimum.

The wiring board of the present invention is a wiring board formed by forming a surface conductor layer made of Ag and an inner conductor layer respectively on the surface and inside of a white substrate body formed by laminating a plurality of insulating layers, Ag is present in the outermost insulating layer located on the outermost side of the insulating layer of the substrate body, and Ag in the outermost insulating layer gradually decreases inward from the outermost surface of the outermost insulating layer. A region in which Ag does not exist is formed on the outermost surface of the outermost insulating layer, and the region exhibits the white system that is the ground color of the substrate body The outermost surface of the outermost insulating layer excluding the region functioning as a recognition mark is colored in a color different from the color of the surface conductor layer , and the outermost surface. Same height as the area Wherein the position near Rukoto of.

  In the present invention, since the Ag in the outermost insulating layer is present so as to gradually decrease inward from the outermost surface of the outermost insulating layer, the outermost surface of the outermost insulating layer of the substrate body is It is colored in a color different from the color of the surface conductor layer made of Ag, so that the image recognition apparatus can accurately recognize the position of the surface conductor layer, and the electronic component can be accurately mounted at a predetermined position of the wiring board.

  Further, Ag exists in the outermost insulating layer of the substrate body, and Ag in the outermost insulating layer is present so as to gradually decrease inward from the outermost surface in the outermost insulating layer. The increase in dielectric loss in the outermost insulating layer is small, and the amount of Ag gradually decreases from the outermost surface having a large amount of Ag in the outermost insulating layer to the inner conductor layer closest to the outermost surface. Even if the inner conductor layer is in contact with the outer insulating layer, the attenuation of the high-frequency signal propagating through the inner conductor layer can be suppressed.

  The wiring board of the present invention is characterized in that a recognition mark made of Ag is provided on the outermost surface of the outermost insulating layer of the substrate body.

  In such a wiring board, the outermost surface of the outermost insulating layer of the white substrate body is colored in a color different from the color of the surface conductor layer made of Ag, and the outermost insulating layer of the white substrate body is outermost. The outer surface is colored in a color different from the color of the recognition mark made of Ag, and the image recognition apparatus can accurately recognize the position of the recognition mark made of Ag, and accurately mount the electronic component at a predetermined position. Can do.

Furthermore, the wiring board of the present invention includes a recognition mark that is formed on an outermost surface of the outermost insulating layer of the substrate body and includes a region where Ag is not present, and exhibits a ground color of the substrate body. It is characterized by.

  In such a wiring board, the outermost surface of the outermost insulating layer of the substrate body is colored in a color different from the color of the surface conductor layer, except for the portion of the recognition mark that exhibits the ground color of the substrate body. The outermost surface of the outermost insulating layer of the substrate body is colored in a color different from the color of the recognition mark that exhibits the white color that is the base color of the substrate body, and the surface of the substrate body that has a flat recognition mark In other words, a white recognition mark having the same height as the wiring board surface is formed on the surface of the wiring board, and there is a difference in light reflectance between the recognition marks. The difference in the light reflectance between the recognition mark and the substrate body can be increased almost without causing an image recognition error due to the convex shape of the recognition mark. Having Accurately recognize the position of the mark can be accurately mounting an electronic component to a predetermined position.

  According to the wiring board of the present invention, the image recognition device can accurately recognize the position of the surface conductor layer and the recognition mark, and can accurately mount the electronic component at a predetermined position of the wiring board, and can be mounted on the outermost insulating layer. Even if the inner conductor layer is in contact, the attenuation of the high-frequency signal propagating through the inner conductor layer can be suppressed.

The wiring board which uses a surface conductor layer as a recognition mark is shown, (a) is a longitudinal cross-sectional view, (b) is a top view. The wiring board of the form which provided the recognition mark separately from the surface conductor layer is shown, (a) is a longitudinal cross-sectional view, (b) is a top view. The wiring board of the form which provided the recognition mark which consists of the ground color of a board | substrate body is shown, (a) is a longitudinal cross-sectional view, (b) is a top view.

  The wiring board of this embodiment will be described with reference to FIG. As shown in FIG. 1, the wiring board A of this embodiment includes a substrate body 1 in which insulating layers 1 a to 1 e are laminated, a surface conductor layer 2 provided on the front and back surfaces of the substrate body 1, and a substrate body 1. The inner conductor layer 3 formed and the via conductor 4 that penetrates the insulating layers 1a to 1e and connects the surface conductor layer 2 and the inner conductor layer 3 are provided. The via-hole conductor 4 (which may be collectively referred to as a conductor layer) is mainly composed of silver.

  On the surface of the wiring board, various electronic components 5 such as a semiconductor element, a filter, and a capacitor are mounted on the surface conductor layer 2 via a connecting member (not shown) such as solder. Then, they are electrically connected by wire bonding or flip chip mounting.

  Moreover, the wiring board A is not limited to the form illustrated in FIG. 1, and may be sealed using a cavity structure, a lid, or the like, and is appropriately selected depending on the application.

<Board body>
The substrate body 1 is a low-temperature fired substrate that can be fired simultaneously with silver, and glass powder alone, or glass powder and various ceramic powders, or various ceramic powders and sintering aid powders are mixed and molded, and have a melting point of silver or lower. It is obtained by firing at a low temperature and has a white color.

  In this embodiment, the composition and crystal phase are not particularly limited, but in particular, by using glass powder, low-temperature firing is facilitated.

Examples of the glass powder to be used include silicate glass, borosilicate glass, borate glass, phosphoric acid glass, and the like. For the network-forming oxides such as SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ . , By appropriately selecting and adding network modified oxides such as alkali metal oxides, rutile earth metal oxides, ZnO and rare earth oxides, and intermediate oxides such as Al ₂ O ₃ , ZrO ₂ and TiO ₂ be able to.

  At this time, in order to prevent an increase in dielectric loss, it is desirable not to use various transition metal oxide powders, whereby a white insulating substrate can be obtained.

  On the other hand, as the crystal phase, alumina, zirconia, quartz, cristobalite, cordierite, mullite, spinel, garnite, enstatite, forsterite, anorthite, slausonite, serdian, diopside, montericite, akermanite, willemite and its solid solution , Substituted derivatives and the like can be exemplified, and a plurality of ceramic phases may coexist, and these crystal phases may be precipitated from the above glass powder during firing, added as raw material powder, May be these reaction products.

  By appropriately combining the glass powder and ceramic powder described above, it is possible to control the ceramic characteristics, thermal characteristics, dielectric characteristics and other porcelain characteristics of the glass ceramic sintered body according to the application.

<Conductor layer>
The surface conductor layer 2, the inner conductor layer 3, and the via-hole conductor 4 are not particularly limited in terms of the composition and crystal phase as long as the main component is silver, and various additives such as Ni and Cu can be used as additives. Metal components, various glasses, various ceramic components such as alumina and zirconia may be contained, but the content of various additives is 20% by mass or less, particularly from the viewpoint of suppressing an increase in resistance of the conductor layer. It is desirable that the amount be 10% by weight or less, and optimally 2% by weight or less. At least a part of the inner conductor layer 3 is an inner conductor layer 3 through which a high-frequency signal propagates.

<Coloring>
In this embodiment, Ag is present in the outermost insulating layer 1a (hereinafter sometimes referred to as the outermost insulating layer 1a) located on the outermost side among the insulating layers 1a to 1e of the substrate body 1, Ag in the outermost insulating layer 1a is present so as to gradually decrease inward from the outermost surface of the outermost insulating layer 1a, and the outermost surface of the outermost insulating layer 1a of the substrate body 1 is a surface conductor layer. It is colored in a color different from the two colors.

  The color tone of the coloring is not particularly limited, but it is desirable because the color tone based on yellow or brown can be easily colored, and the entire surface of the substrate body is visually the same color, almost uniformly. This is desirable in order to reduce the recognition error rate in image recognition.

  That is, Ag is present in the outermost insulating layer 1a of the uppermost layer of the substrate body 1 in FIG. 1 (a), and the amount thereof is small from the upper surface of the outermost insulating layer 1a downward. In particular, although the upper surface of the outermost insulating layer 1a has a certain number of upper surfaces, the outermost insulating layer 1a is extremely reduced as it leaves the upper surface. It is important that the outermost insulating layer 1a as a whole is not colored in order not to increase dielectric loss.

As described later, this is not to add a coloring material (Ag) to the green sheet, but to diffuse Ag from the firing jig at the time of firing so that the Ag is dispersed as described above. it can.

  In such a wiring board, Ag is volatilized from the firing jig and adsorbed on the surface of the outermost insulating layer 1a. Therefore, the amount of Ag in the outermost insulating layer 1a is small, and Ag dissolved in the glass is contained in the glass. By re-depositing, a different color (yellow) from the case where the Ag paste is applied and present as Ag (usually silver) is obtained. Moreover, when Ag melt | dissolved in glass reprecipitates out of glass, it comes to exhibit brown.

  On the other hand, since only the vicinity of the outermost surface of the outermost insulating layer 1a is colored, the increase in the dielectric loss in the outermost insulating layer 1a is not substantially affected. It can be suppressed to 1.1 or less.

  Regarding the depth direction of the wiring board to be colored, the outermost surface of the outermost insulating layer 1a has the deepest color tone, and the color tone gradually becomes thinner toward the inside of the substrate body 1. Regarding the coloring range, Although it is not particularly limited as long as it is effective in reducing the recognition error rate and does not substantially increase the dielectric loss, it is visually observed from the viewpoint that the increase in dielectric loss can be further reduced. The range of the colored portion that can be recognized in FIG. 5 is desirably 100 μm or less, more preferably 75 μm or less, and most preferably 50 μm or less from the outermost surface of the outermost insulating layer 1a.

  In FIG. 1, the insulating layer 1a disposed on the upper surface of the wiring substrate is colored. However, the insulating layer 1e disposed on the lower surface of the wiring substrate may be colored, and the insulating layers 1a and 1e may be colored. Of course, both may be colored.

  Conventionally, when the surface conductor layer 2 made of Ag is formed on the surface of the white substrate body 1, the color tone and light reflectance of the surface of the substrate body 1 and the surface conductor layer 2 made of Ag are approximate. Therefore, when the position of the surface conductor layer 2 is recognized by the image recognition device and the electronic component 5 such as a semiconductor element or a capacitor is mounted on the wiring board by the automounter, the image recognition device accurately determines the position of the surface conductor layer 2. However, in this embodiment, there is a problem that the electronic component 5 cannot be accurately mounted at a predetermined position of the wiring board. Since the outermost surface is colored in a color (yellow or brown) different from the color (silver) of the surface conductor layer 2 made of Ag, the image recognition device can accurately recognize the position of the surface conductor layer 2, and the electronic component 5 is a predetermined wiring board A It can be accurately mounted on the location.

  Further, Ag is present in the outermost insulating layer 1a of the substrate body 1, and Ag in the outermost insulating layer 1a is present so as to gradually decrease from the outermost surface in the outermost insulating layer 1a toward the inside. Since the outermost surface of the outermost insulating layer 1a of the substrate body 1 is colored, the increase in dielectric loss in the outermost insulating layer 1a is small and the amount of Ag present in the outermost insulating layer 1a is large. Since the amount of Ag gradually decreases from the outer surface to the inner conductor layer 3 facing the outermost insulating layer 1a, the inner conductor layer 3 facing the outermost insulating layer 1a, in other words, the outermost insulating layer 1a and the insulating layer 1b Even if the inner conductor layer 3 is formed between the two, the attenuation of the high-frequency signal propagating through the inner conductor layer 3 can be suppressed.

  FIG. 2 shows another form of the wiring board, and this form of the wiring board B is similar to FIG. 1 in that the substrate body 1 on which the insulating layers 1a to 1e are laminated, and the front and back surfaces of the substrate body 1. The surface conductor layer 2 provided, the inner conductor layer 3 formed in the substrate body 1, and the via-hole conductor 4 that penetrates the insulating layers 1a to 1e and connects the surface conductor layer 2 and the inner conductor layer 3, respectively. The surface conductor layer 2, the inner conductor layer 3, and the via-hole conductor 4 (these may be collectively referred to as a conductor layer) are mainly composed of silver.

In this embodiment, a ring-shaped recognition mark 13 made of Ag is formed on the surface of the substrate body 1, and the center of the ring-shaped recognition mark 13 is the same as the color of the ring-shaped recognition mark 13 made of Ag. It has a different color (yellow or brown). Of course, the recognition mark 13 is not limited to a ring shape, and may be a circle, a triangle, a quadrangle, or the like.

  In such a wiring board B, as in the case of FIG. 1, an increase in dielectric loss in the outermost insulating layer 1a based on coloring can be minimized, and attenuation of a high-frequency signal propagating through the inner conductor layer 3 can be suppressed.

  Further, in this embodiment, the outermost surface of the outermost insulating layer 1a of the white substrate body 1 is colored in a color different from the color of the surface conductor layer 2 made of Ag, as in the embodiment of FIG. The outermost surface of the outermost insulating layer 1a of the white substrate body 1 is colored in a color (yellow or brown) different from the color (silver) of the recognition mark 13 made of Ag. Can accurately recognize the position of the recognition mark 13 made of Ag, and can accurately mount the electronic component 5 at a predetermined position.

  FIG. 3 shows still another form of the wiring board C. The wiring board C of this form is similar to FIG. 1 and includes a board body 1 on which insulating layers 1a to 1e are laminated, and a surface of the board body 1. A via-hole conductor 4 that penetrates the surface conductor layer 2 provided on the back surface, the inner conductor layer 3 formed in the substrate body 1, and the insulating layers 1 a to 1 e and connects the surface conductor layer 2 and the inner conductor layer 3. The surface conductor layer 2, the inner conductor layer 3, and the via-hole conductor 4 (these may be collectively referred to as a conductor layer) are mainly composed of silver.

  And in this form, the recognition mark 15 which exhibits the ground color of the board | substrate body 1 is provided in the surface of the board | substrate body 1 separately from the surface conductor layer 2. FIG. That is, the recognition mark 15 has a ring shape that exhibits the white color of the ground color of the substrate body 1.

  In such a wiring board C, as in the case of FIG. 1, an increase in dielectric loss in the outermost insulating layer 1a based on coloring can be minimized, and attenuation of a high-frequency signal propagating through the inner conductor layer 3 can be suppressed.

  Furthermore, since the outermost surface of the outermost insulating layer 1a of the substrate body 1 is colored in a color different from the color of the surface conductor layer 2 except for the portion of the recognition mark 15 that exhibits the ground color of the substrate body 1, The outermost surface of the outermost insulating layer 1a of the substrate body 1 is colored in a color (yellow or brown) different from the color of the white recognition mark 15 that is the ground color of the substrate body 1, and The recognition mark 15 is formed on the surface of the flat substrate body 1.

  In other words, the white recognition mark 15 having the same height as the surface of the wiring board C is formed on the surface of the wiring board C, and there is almost no difference in the reflectance of the light at the recognition mark 15. 15 and the substrate body 1 can be made to have a large difference in light reflectance, and an image recognition error due to the convex shape of the recognition mark 15 can be avoided. The position of the recognition mark 15 can be accurately recognized, and the electronic component can be accurately mounted at a predetermined position. The white recognition mark 15 having the same height as the surface of the wiring substrate C is formed on the outermost surface of the outermost insulating layer 1a of the substrate body 1 from a region where Ag is not present.

That is, since the recognition mark is usually formed on the substrate body 1 by printing, the recognition mark has a convex shape of about several μm to several tens of μm from the surface of the substrate body 1, and its cross-sectional shape is also a gentle curve. Furthermore, the reflectance is partially different due to the unevenness of the conductor particles, the difference in surface condition, etc., and a recognition error may occur particularly when the reflection is strong locally. In this embodiment, the recognition mark 15 is not formed using a conductive paste, and the unevenness of the recognition mark 15 is equivalent to the surface roughness of the substrate body 1, thereby avoiding the occurrence of a recognition error as described above. be able to.

<Manufacturing method>
A method for manufacturing the wiring board of this embodiment will be described. The method of manufacturing the wiring board of the present embodiment includes a step of producing a green sheet that becomes white after firing, a step of forming a conductive pattern mainly composed of silver on the green sheet, and a plurality of green sheets on which the conductive pattern is formed. A method of manufacturing a wiring board comprising a step of producing a laminated molded body and a step of firing the laminated molded body, wherein a porous firing jig in which silver is adsorbed in advance on the surface and the laminated molding The body is brought into contact with and fired. The recognition mark can be formed on a green sheet serving as the outermost insulating layer with a conductor pattern mainly composed of silver.

  That is, first, a green sheet for forming an insulating layer after firing is prepared. An appropriate organic resin binder, a solvent, and the like are added to glass powder alone, or a raw material powder composed of glass powder and various ceramic powders, or various ceramic powders and sintering aid powder, and then mixed to obtain a slurry. Using the obtained slurry, a green sheet is produced by a desired forming means such as a doctor blade method, a calender roll method, a rolling method or the like.

  Next, among the plurality of green sheets, a plurality of through holes are formed in a desired green sheet by punching, laser processing, or the like, and these through holes are filled with via-hole conductor paste.

  In the via-hole conductor paste, silver powder as a main component and various additive powders are weighed at a desired blending ratio, an appropriate organic resin binder, a solvent and the like are added and mixed to obtain a via-hole conductor paste.

  Also, a conductor pattern to be the surface conductor layer 2 and the inner conductor layer 3 is formed on a desired green sheet by a screen printing method or gravure printing using a conductive paste mainly composed of silver produced by the same method as a via-hole conductor. Form by the method. In the wiring board of FIG. 2, not only the conductor pattern that becomes the surface conductor layer 2 and the inner conductor layer 3, but also the conductor pattern that becomes the recognition mark 13 is formed by a screen printing method or a gravure printing method. The conductor pattern may be formed by a metal foil transfer method or a plating method.

  Next, a plurality of green sheets are aligned, pressed using a thermocompression bonding method or a laminating aid, and laminated to obtain a laminated molded body.

  Finally, in order to remove the organic resin binder component blended for molding from the laminated molded body, for example, the temperature is raised to about 500 ° C. in the atmosphere so that there is no peeling of the laminated interface of the laminated body, Accordingly, by holding at around 500 ° C., and then raising the temperature again to around 900 ° C. in the atmosphere and firing at the highest firing temperature for 0.2 to 10 hours, particularly 0.5 to 5 hours, A wiring board can be obtained.

  In the wiring board of this embodiment, a porous firing jig (hereinafter sometimes referred to as a shelf board) having silver adsorbed on the surface in advance is brought into contact with the laminate and fired.

The porous shelf board is not particularly limited as long as it can efficiently attach and detach silver, which will be described later, and can uniformly color the wiring board surface. Is preferably 15 to 40% by volume, particularly preferably 20 to 35% by volume, and the material is SiO ₂ —Al ₂ O ₃ based composite fiber, SiO ₂ —Al ₂ O ₃ , Si
Examples include O ₂ , Al ₂ O ₃ , spinel, SiC, and the like.

  Coloring may be performed only on the surface requiring image recognition, and the shelf board to which silver is attached may be fired by contacting only the front surface or the back surface of the wiring board.

  As a method for adsorbing silver on a porous shelf board, for example, plate-like silver and a porous shelf board are brought into contact with each other, and in the atmosphere at about 800 to 950 ° C. for 0.2 to 2 hours, particularly 0. The porous shelf board to which silver was made to adhere by baking for about 5 to 1 hour can be obtained.

  3 is manufactured by applying a recognition mark paste containing a dye on a green sheet on which the recognition mark 15 is formed, and using the same method for other processes. Can do.

  The recognition mark paste is obtained by adding a dye and a suitable organic resin binder, solvent, etc., and then mixing it. The dye may be burned off from the surface of the wiring board by evaporating and burning with heat during firing. For example, general oil-based inks, water-based inks, fluorescent inks and the like can be exemplified.

  That is, on the green sheet that forms the recognition mark, a ring-shaped recognition mark is written with oil-based ink or the like, and the shelf plate to which silver is attached is brought into contact with the surface on which the ring-shaped recognition mark of the laminated molded body is written. By baking in this state, the ring-shaped recognition mark portion described with oil-based ink or the like does not diffuse silver, but forms a ring-free region where silver is not diffused. While the portion exhibits the white ground color of the wiring board, silver diffuses in other portions except the surface layer conductor layer, and exhibits a different color (yellow or brown) from the surface layer conductor layer.

  Glass powders a, b and c having an average particle size of 2.0 μm having the composition shown in Table 1, an alumina powder having an average particle size of 2.0 μm shown in Table 2, and a pigment powder shown in Table 2 were prepared. The organic binder, the plasticizer, and the solvent were mixed with this to prepare a slurry, and a green sheet having a thickness of 100 μm was prepared by the doctor blade method using the obtained slurry.

  On the other hand, in order to prepare a shelf board for firing having the material and porosity shown in Table 2 in advance, and to uniformly adhere silver to the shelf board surface, the plate-like silver is sandwiched between the shelf boards, in the atmosphere, at 850 ° C., A porous shelf plate with silver attached thereto was prepared by firing under conditions of 0.5 hour. Moreover, the shelf board which does not adhere silver as a comparative example was also prepared.

  A laminated molded body was prepared by laminating 10 layers of green sheets by thermocompression bonding so that the thickness was 1.0 mm, and after being treated with a deorganic binder by heat treatment at 500 ° C. for 2 hours in the atmosphere, Table 2 A wiring board without a surface conductor layer, an internal conductor layer, and a via-hole conductor layer by firing at 900 ° C. for 1 hour in an air atmosphere using a shelf board having the composition and porosity shown in FIG. Got.

  Table 3 shows the results of measuring the dielectric loss at 10 GHz of the obtained wiring board by the cavity resonator method (JIS R1641). Further, in each sample, the change rate of the dielectric loss with respect to the reference sample not containing the pigment and not subjected to the coloring treatment was calculated, and the result is shown in Table 3.

Furthermore, a ring-shaped recognition mark (outer diameter 0.4 mm, inner diameter 0.2 mm) is formed on the surface of the green sheet by a screen printing method using a silver paste mainly composed of silver. A green sheet was placed on the surface of the wiring board and laminated and fired in the same manner to obtain a wiring board.

  The color tone of the obtained wiring board was visually observed, and the results are shown in Table 3. Whether or not the color tone is uniform was confirmed by visual confirmation using a binocular stereomicroscope with a magnification of 10 times.

  A total of 1000 recognition marks were recognized by repeatedly measuring 50 recognition marks on the obtained wiring board 20 times. Table 3 shows the probability that a recognition error occurred.

  As is apparent from Tables 1 to 3, the sample No. In 10-12, 15-17, and 20-22, the substrate body is made of white ceramics containing no pigment powder, and the vicinity of the outermost surface of the outermost insulating layer is colored, so that the dielectric of the substrate body is reduced. It can be seen that recognition errors by the image recognition apparatus can be avoided without substantially changing the loss.

  On the other hand, Sample No. in which the vicinity of the outermost surface of the outermost insulating layer is not colored. In 1, 13, and 18, many recognition errors occurred. Furthermore, Sample No. containing pigment powder in the substrate body. In 2-9, 14 and 19, the dielectric loss increased. Sample No. 2-9, 14 and 19 are cases where pigment powder is contained in all the insulating layers. For example, even in the invention described in Patent Document 4, the outermost insulating layer has a large dielectric loss and the outermost insulating layer It can be seen that when the inner conductor layer is formed facing the layer, the attenuation of the high-frequency signal is large.

  Sample No. in Table 2 The above-mentioned recognition mark is formed by screen printing using an ink (oil-based ink) containing a dye on 10 green sheets, and the green sheet with the recognition mark is arranged in the outermost layer. A wiring substrate was obtained by laminating and firing in the same manner as in Example 1. The wiring board thus obtained was referred to as Sample No. 100.

  As a result of measuring the shapes of the recognition marks on these wiring boards with a laser three-dimensional measuring instrument, The thickness of Sample No. 10 was 12 μm. In 100, the thickness was 1 μm or less, which was the same height as the wiring board surface.

Moreover, as a result of visually observing the color tone of the obtained insulating substrate, sample No. 1 in which a ring-shaped recognition mark was formed by screen printing using a silver paste was used. 10 is silver and sample N
o. In 100, nothing was present in the ring-shaped portion described with the ink containing the dye, and a white ring-shaped recognition mark, which is the ground color of the substrate body, was formed.

  Sample No. 10 and no. When 100 recognition marks were repeatedly measured 200 times for 100 samples, a total of 10,000 recognition marks were recognized, and the probability that a recognition error occurred was calculated. 10 with a recognition error rate of 0.06%, The recognition error rate of 100 was less than 0.01%.

DESCRIPTION OF SYMBOLS 1 ... Substrate body 1a ... Outermost insulating layer 1b-1e ... Insulating layer 2 ... Surface layer conductor layer 3 ... Internal conductor layer 4 ... Via hole conductor 5 ... Electronic component 13. ..Recognition marks formed by conductors 15 ... Recognition marks consisting of the ground color of the board body

Claims (1)

A wiring board formed by forming a surface conductor layer made of Ag and an inner conductor layer on the surface and inside of a white substrate body formed by laminating a plurality of insulating layers,
Ag is present in the outermost insulating layer located on the outermost side among the insulating layers of the substrate body, and Ag in the outermost insulating layer gradually increases inward from the outermost surface of the outermost insulating layer. Exist to be less,
A region in which Ag does not exist is formed on the outermost surface of the outermost insulating layer, and the region functions as a recognition mark that exhibits the white color that is the ground color of the substrate body, and the recognition The outermost surface of the outermost insulating layer excluding the region functioning as a mark is colored in a color different from the color of the surface conductor layer , and the outermost surface and the region have the same height. position near Ru, wiring board.

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