JP4396426B2 - Resistance element and multilayer printed wiring board incorporating the resistance element - Google Patents

Description

  The present invention relates to a resistance element and a multilayer printed wiring board incorporating the resistance element.

  In recent years, with the demand for higher performance and smaller size of electronic devices, the density and functionality of circuit components are increasing. Therefore, when electronic components are mounted on a multilayer printed wiring board, a multilayer having a structure in which passive components such as a capacitor (C), a resistor (R), and an inductor (L) are built in the substrate in order to increase the mounting efficiency. Printed wiring boards are attracting attention.

  For example, a method of embedding a leadless circuit component in a hole provided in a printed circuit board (see, for example, Patent Document 1), a method of embedding a passive component such as a ceramic capacitor in a through hole provided in an insulating substrate (for example, Patent Document 2), and a method of embedding a bypass capacitor of a semiconductor element in a hole of a printed circuit board (for example, refer to Patent Documents 3 and 4).

  However, when embedding and mounting a chip capacitor having a large capacity in advance by the above method in a through-hole, the layer thickness is 0.3 mm or 0.6 mm even if the smallest size 0603 chip is used at present. Therefore, it is difficult to realize a thin multilayer printed board of the present level, and there is a concern that cracks may occur due to the difference in thermal expansion coefficient between the insulating resin and the chip component.

  Therefore, a dielectric paste in which a high dielectric filler such as barium titanate is dispersed in a binder resin, or a resistive paste in which conductive particles such as carbon are dispersed in a binder resin is screen-printed to form a capacitor element or a resistive element in a multilayer printed wiring board. Many methods have been devised, and after embedding an electronic component forming material in a through hole provided in an organic insulating substrate and solidifying it, electrodes are formed on the upper and lower end surfaces of the electronic component forming material to form capacitors and A method of forming a resistor (for example, see Patent Document 5) is disclosed.

  FIG. 3 is a partially enlarged view of an example of a conventional multilayer printed wiring board with a built-in resistance element, where a is a side sectional view and b is a plan view. A pair of first electrodes 21 was formed on the core substrate 10, and a resistor 50 was formed between the electrodes. As shown in FIG. 3, the resistor 50 is formed directly on the first electrode 21. However, when the resistance element is formed by the above-described method, the electrode made of a part of the copper wiring and the resistor made of carbon paste are in direct contact with each other (FIG. 3). Under humid conditions (temperature 40 ° C., relative humidity 95%), it has been reported that the resistance value greatly increases due to interface corrosion or the like, which is problematic (for example, see Non-Patent Document 1).

  FIG. 4 is a partially enlarged view of an example of a conventional multilayer printed wiring board with a built-in resistance element, where a is a side sectional view and b is a plan view. A pair of first electrodes 21 was formed on the core substrate 10, a second electrode was formed on the first electrode 21, and a resistor 50 was formed between the second electrodes. As shown in FIG. 3, the resistor 50 is formed on the first electrode 21 and the resistor 50 through the second electrode. Therefore, a resistance element (FIG. 4) having a structure in which a silver paste excellent in electrical connectivity is sandwiched between an electrode and a resistor to reduce the contact resistance at the interface has been reported (for example, Non-Patent Document 1, Patent). Reference 6). By adopting such a structure, it is possible to form a resistance element having excellent stability with little variation in resistance value even when temperature and humidity change.

However, when a resistor is manufactured with the structure shown in FIG. 4, the length of the resistor is the distance between the silver pastes printed on the electrodes and the inside of the electrodes, so the printing accuracy of the silver paste affects the element capacity and etching. Compared to the structure of FIG. 3 in which the distance between the electrodes made of copper or the like formed in step 3 becomes the length of the resistor, the distance between the silver paste formed by printing becomes the structure of FIG. Since the printing accuracy is inferior, it is difficult to match the printing accuracy to the design value of the element capacity, and there is a problem that laser trimming is necessary to increase the accuracy of making. That is, laser trimming for correcting the shape is required. Furthermore, when a thermal cycle test (hereinafter referred to as TCT) is performed in order to print a silver paste highly filled with a silver filler in order to realize good conductivity on a stepped portion between the electrode and the substrate insulating resin, There is a concern that cracks will occur at the edge of the electrode.

The known literature is described below.
JP-A-54-38561 Japanese Patent Publication No. 60-41480 JP-A-4-73992 JP-A-5-218615 Japanese Patent Laid-Open No. 10-56251 Japanese Patent Laid-Open No. 11-340633 Isao Shioka: “Polymer resistors used in embedded passive component technology”, Journal of Japan Institute of Electronics Packaging, Vol. 6, no. 4, pp. 294-299, 2003

  The object of the present invention is a resistance element used for a printed wiring board with a built-in passive element as a passive component such as an inductor, a capacitor, and a resistor in a multilayer printed wiring board, without sacrificing the stability of the resistance value. It is to adjust the element capacity to the design value without laser trimming, to suppress the generation of cracks, and to reduce the total thickness of the substrate by reducing the thickness of the paste cured product. As a result, it is an object of the present invention to provide a resistive element and a multilayer printed wiring board incorporating the resistive element that are inexpensive and excellent in reliability.

  According to a first aspect of the present invention, there is provided a resistance element in which a resistor is formed between a pair of first electrodes formed on an insulating layer, the inner end of the first electrode on the first electrode. A second electrode having a size equal to or smaller than that of the first electrode and the second electrode and the other first electrode and the second electrode is provided between the first electrode and the second electrode. A resistance element is provided in which a resistor is provided so as to be in contact with the inner end portion and the second electrode.

  According to this invention, the second electrode is formed on the electrode leaving the inner end portion inside the first electrode, and the resistor is formed so as to be in contact with both the inner end portion of the first electrode and the second electrode. As a result, the distance between the first electrodes formed by etching of the element capacitance of the resistor becomes the length of the resistor, so that the element capacitance can be adjusted to the design value without laser trimming. In addition, it is possible to form a resistance element having excellent resistance value stability.

  The invention according to claim 2 of the present invention is the resistance element according to claim 1, wherein the inner end portion of the first electrode is provided at a position having a length of 50 to 200 μm.

  According to the present invention, the inner end of the first electrode is left in a range in which the second electrode does not enter the insulating layer from the electrode due to misalignment of printing or the like, and the resistor that is in direct contact with the first electrode can be provided as much as possible. By reducing the number, it is possible to achieve both the adjustment of the element capacitance to the design value and the stability of the resistance value.

  According to this invention, since the partition region of the second electrode is formed only on the first electrode, the distance between the first electrodes formed by etching becomes the length of the resistor, and the element of the resistor Capacity is stable.

  The invention according to claim 3 of the present invention is the resistance element according to claim 1 or 2, wherein an inner end portion of the first electrode is thinner than other portions of the first electrode.

  According to the present invention, if necessary, the first electrode is thinned by a method such as half-etching so that the total thickness of the portion where the first electrode, the second electrode, and the resistor overlap is embedded. Can be thinned to a suitable thickness. In addition, since the step between the insulating layer and the first electrode is reduced, it is difficult for the resistor formed on the step to be cracked.

  The invention according to claim 4 of the present invention is the resistance element according to any one of claims 1 to 3, wherein the resistor is formed of a resistance paste.

  The invention according to claim 5 of the present invention is the resistance element according to any one of claims 1 to 4, wherein the second electrode is made of a noble metal.

  The resistance element according to any one of claims 1 to 5, wherein the first electrode is a part of a conductor layer constituting a multilayer printed wiring board. It is.

  According to a seventh aspect of the present invention, there is provided a multilayer printed wiring board comprising the resistance element according to any one of the first to sixth aspects.

  According to this invention, the prepreg used for the multilayer printed wiring board, the adhesive layer of the resin-coated copper foil, the same material as the material used for the build-up insulating material, and the carbon filler available at low cost are used. As a result, it is possible to provide an inexpensive multilayer printed wiring board with a built-in resistance element that is excellent in reliability without causing delamination.

  According to the present invention, a conventional noble metal paste such as silver is formed on the first electrode and on the inner end of the electrode by reducing the thickness of the first electrode and the second electrode to the minimum necessary thickness. The design error can be reduced by making the length of the resistor the distance between the first electrodes that can be formed by etching while ensuring the same resistance value stability and substrate thickness as the above structure. Since it is formed only on the electrode, the size of the resistor can be reduced. In addition, since a part of the first electrode is thinned in advance by half-etching or the like, there are merits such that the level difference is reduced and the connection reliability of the second electrode is increased. Therefore, it is effective in reducing the manufacturing cost, shortening the manufacturing delivery time, making the substrate lighter and thinner, improving the reliability, etc. by trimming-less.

  Hereinafter, an example of a multilayer printed wiring board incorporating a resistance element according to the present invention will be briefly described with reference to the drawings.

FIG. 1 is a partially enlarged view of a multilayer printed wiring board with a built-in resistance element according to the present invention, in which a is a side sectional view, b is a plan view, and c is a plan view for explaining the arrangement of components.

  In the multilayer printed circuit board 100 with a built-in resistance element shown in FIG. 1a, the second electrode 40 is formed on the pair of first electrodes 21 while leaving a part of the inner end of each first electrode. A resistive element in which a passive element resistor 50 is formed between a pair of first electrodes 21 so that both ends of the resistor are in contact with a position including both the electrode, the inner end of the first electrode, and the second electrode This is a built-in multilayer printed wiring board 100.

  The inner end portion inside the first electrode shown in FIG. 1b is a region where the second electrode is not formed. That is, it is a prohibited area for forming the second electrode. With this, when the resistor is formed, the element capacitance of the resistor is the distance between the first electrodes formed by etching is the length of the resistor. Furthermore, considering the printing position accuracy in the resistor forming printing method, the distance from the inner end of the first electrode to the inner end of the second electrode (the inner end of the first electrode) It is a multilayer printed wiring board with a built-in resistance element provided with a resistance element in the range of 50 to 200 μm.

  The first electrode in the vicinity region including the inner end portion of the first electrode is a resistor electrode region, and the thickness is reduced to a range of 10 to 20 μm, and a multilayer with a built-in resistor element is formed. It is a printed wiring board. Therefore, when the resistor is formed, the step is greatly reduced at the inner tip portion of the first electrode, and cracks are hardly generated in the resistor at the position.

  FIG. 1c is a layout view of passive element components. A pair of first electrode formation regions 29 are provided on the insulating resin layer of the substrate 10, and a resistor formation region is provided at an inner tip in the first electrode formation region. 59, and the second electrode formation prohibition region 45 and the second electrode formation region 49 are partitioned and arranged at the inner end portion of the first electrode in the region. The inner end portion of the first electrode is a second electrode formation prohibition region 45.

  FIG. 2 is a side cross-sectional view for explaining a method of manufacturing a multilayer printed wiring board with a built-in resistance element according to the present invention, and a to i are process diagrams thereof.

  The substrate to be loaded is a substrate 10 of a single-sided copper-clad laminate of a core substrate (see FIG. 2a). In the next step, the copper foil 1 on the surface of the substrate 10 is etched to form a conductor wiring layer 20 comprising a conductor circuit and a first electrode 21 including a resistor electrode 22 (see FIG. 2b). Next, after half-etching only the resistor electrode 22 using the photosensitive resist 30 (see FIG. 2c), a silver paste is screened on the resistor electrode 22 while leaving about 100 μm inside the resistor electrode 22. Printing is performed, and the second electrode 40 of the silver paste is cured at a predetermined curing temperature and time (see FIG. 2d). At this time, the thickness of the second electrode 40 of the silver paste is preferably around 15 μm. Further, between the first electrodes 21 printed with the silver paste, the resistor 50 is screen-printed so as to come into contact with both the inner end portion of the first electrode 21 and the second electrode 40 of the silver paste, and predetermined curing is performed. Cure at temperature and time (see FIG. 2e). At this time, the thickness of the resistor 50 is preferably about 20 μm. In this way, the build-up insulating resin 60 is laminated on the substrate 10 on which the resistor 50 is formed with a vacuum pressurizing laminator, the resin surface is smoothed with a flat press machine, and then insulated at a predetermined curing temperature and time. The resin 60 is cured (see FIG. 2f). The next step is to drill the via hole 70 by CO2 laser processing (see FIG. 2g), and then form a via in the hole by performing electroless copper plating and electrolytic copper plating plating conductor layer 8 and forming the conductor layer. Then, the lower conductor wiring layer 20 and the upper plated conductor layer 8 are electrically connected (see FIG. 2h). In the next step, the plated conductor layer 8 is etched to form the wiring pattern 80, whereby the multilayer printed wiring board 100 with a built-in resistance element in which the resistor 50 is built in the inner conductor wiring layer 20 can be formed. (See FIG. 2i). Note that a double-sided copper-clad laminate may be used as a core substrate to form a buildup layer on both sides, and two or more buildup layers are formed, and a resistance element is formed on a layer other than the core. It may be a structure.

  In the method for manufacturing a multilayer printed wiring board with a built-in resistance element of the present invention, the first electrode is formed by etching a thin conductive wiring layer using a photo process method, and the second electrode is formed by a printing method. Use to partition the conductive noble metal paste directly. The distance between the first electrodes formed by etching is the structure of the length of the resistor, and the second electrode silver paste that is partitioned by printing has a printing accuracy distance that is inferior to the etching accuracy. According to the printing method, the structure is not affected by the element capacity of the resistor, and it is easy to adjust the printing accuracy to the design value, and there is an effect that laser trimming is unnecessary to increase the accuracy of the manufacturing.

  Since the resistor electrode 22 in the present invention needs to print the second electrode 40 of the noble metal paste and the resistor 50 of the resistor paste on the first electrode 21, the interlayer thickness and prepreg of the multilayer printed wiring board to be manufactured Considering the embedding property of the adhesive layer of the copper foil with resin and the build-up insulating resin, it is preferable to make it as thin as possible without impairing the conductivity. As a result of the examination, it was found that when the thickness of the resistor electrode 22 is in the range of 10 to 20 μm, a multilayer printed wiring board having an interlayer thickness of about 100 μm can be manufactured without impairing the conductivity of the first electrode 21. Further, for the purpose of improving the adhesion between the second electrode 40 of the noble metal paste formed on the first electrode 21 and the resistor 50 of the resistor paste, the surface of the first electrode 21 including the resistor electrode 22 is blackened in advance. It is preferable to perform surface treatment such as treatment.

  The noble metal paste in the present invention is printed leaving a part of the inside of the electrode. If the area where no precious metal paste is printed on the electrode is taken too long than the inner edge of the electrode, the influence of the part where the resistor and the copper electrode are in direct contact increases, and the contact resistance increases, the resistance element size increases. On the other hand, if the region where the noble metal paste is not printed on the electrode is made too short from the inner edge of the electrode, the paste will be transferred from the first electrode including the resistor due to misalignment during printing of the noble metal paste. As a result, the section of the second electrode of the noble metal paste is formed on the insulating layer, and as a result, there is a risk that the resistance value is greatly deviated from the design value. As a result of the examination, although depending on the alignment accuracy of the screen printing machine, if the region inside the first electrode where the second electrode of the noble metal paste is not printed is within the range of 50 μm to 200 μm from the end of the electrode, contact resistance It was found that it was easy to adjust the resistance value to the design value. The region inside the first electrode is partitioned and formed at a distance from an inner electrode end of each of the pair of first electrodes to an inner electrode end of the second electrode on the electrode, and the distance is 50 μm to 200 μm. If it is within the range, the alignment accuracy of the screen printing machine can be absorbed.

The noble metal paste in the present invention can be selected from commercially available conductive pastes. Silver, silver-carbon, gold, palladium, silver-palladium alloy, silver-plated copper powder, etc. can be used as the precious metal filler used in the precious metal paste, but silver is considered in consideration of contact resistance with carbon and cost. It is particularly preferable to use it as a noble metal filler. The particle diameter of the noble metal filler is preferably in the range of 1 to 5 μm. This is because when the particle system is significantly less than 1 μm, aggregation of the noble metal filler dispersed in the paste becomes a problem, and when it exceeds 5 μm, the surface smoothness of the coating film is deteriorated and the thickness after curing is 20 μm or less. This is because the filler system is too large and the conductivity becomes poor. In addition, as the binder resin used in the noble metal paste, a thermosetting resin such as an epoxy resin, a phenol resin, a melamine resin, or a polyimide resin, a resin obtained by modifying these, or a mixture of these resins and a thermoplastic resin is used. be able to. Especially, it is preferable to use an epoxy resin from the point of adhesiveness with a base material, chemical resistance, and cost. Furthermore, since the thickness of the precious metal paste after curing requires that a precious metal paste cured product and a resistance paste cured product be formed on the electrode, the interlayer thickness and prepreg of the multilayer printed wiring board to be produced, the resin-coated copper foil In consideration of the embedding property of the adhesive layer and the build-up insulating resin, it is preferable to make the thickness as thin as possible without impairing the conductivity. As a result of the study, it was found that a multilayer printed wiring board having an interlayer thickness of around 100 μm can be produced without impairing the electrical conductivity if the thickness of the cured noble metal paste is in the range of 10 to 20 μm.

  The resistance paste used in the present invention can be selected from commercially available carbon pastes. As the binder resin used for the carbon paste, it is possible to use a thermosetting resin such as an epoxy resin, a phenol resin, a melamine resin, a polyimide resin, a modified resin thereof, or a mixture of these resins and a thermoplastic resin. it can. Especially, it is preferable to use an epoxy resin from the point of adhesiveness with a base material, chemical resistance, and cost. As a filler component contained in the carbon paste, an inorganic filler such as silica may be added in addition to the carbon powder. Since the thickness of the carbon paste cured product is formed at the step portion of the electrode or silver paste, it is preferable that the carbon paste cured product is formed to have a thickness of 15 to 25 μm, which is slightly thicker than the noble metal paste.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

  About the characteristic of the built-in resistance element by performing resistance value measurement, high-temperature and high-humidity test, and thermal cycle test (TCT) for the multilayer printed wiring board with the built-in resistance element built in each example and comparative example. evaluated. The evaluation method is as follows.

  In the resistance value measurement, resistance values are measured with a multimeter for 100 elements having a resistance element design value of 100Ω among the resistance element built-in substrates manufactured in each of the examples and comparative examples, and the average resistance value and the standard deviation (σ ) The value of 3σ was calculated and the degree of variation in resistance value was evaluated.

  In the high-temperature and high-humidity test, the high-temperature and high-humidity test at 40 ° C. and 95% was performed for 1000 hours on the resistive element-embedded substrates manufactured in each Example and Comparative Example, and the change in resistance value was calculated from the resistance values before and after the test.

In TCT, the resistance element built-in substrate manufactured in each Example and Comparative Example was subjected to 1000 cycle TCT under conditions of a low temperature bath of −40 ° C., a high temperature bath of 125 ° C., and an exposure time of 30 minutes, and the resistance value after the test was 10 ⁶ Ω. The element which became the above was determined to be defective due to cracks. For each example and comparative example, 100 devices having a design value of 100Ω were tested.

After degreasing and cleaning the 0.6 mm thick BT resin double-sided copper-clad laminate (Mitsubishi Gas Chemical Co., Ltd.) with a copper thickness of 35 μm, laminating the resist of the mask for etching, and exposing the resist for pattern transfer The development process was carried out, and the copper foil of an unnecessary part was etched using this resist pattern as an etching mask to form a first electrode including a conductor circuit and a resistor electrode. At this time, the width of the resistor electrode was 400 μm. Next, the resist for etching was laminated, exposed and developed again on the substrate, and only the resistor electrode of the first electrode was opened, and the copper foil of the resistor electrode was half-etched to a thickness of about 15 μm. A conductive silver paste LS-504J (manufactured by Asahi Chemical Laboratories) was screen-printed on the remaining 300 μm area on the remaining 300 μm area on the resistor electrode formed in this manner. When the film thickness of the second electrode of the silver paste was measured after drying and curing, the film thickness was about 15 μm. A second electrode of silver paste was thus formed. Resistor paste carbon paste TU-100-8 (Asahi Chemical Laboratory Co., Ltd.) was screen-printed on the electrode. Next, when the thickness of the carbon paste resistor was measured after drying and curing the substrate, the thickness was about 20 μm. Next, a resin-coated copper foil ARCC R-0870 (manufactured by Matsushita Electric Industrial Co., Ltd.) was laminated on the substrate with a vacuum press at a pressure of 30 kgf / cm 2 and a temperature of 170 ° C. for 1 hour, and then the copper in the via formation portion. The foil was etched, and further, an insulating layer was drilled with a CO2 laser to process via holes. Thereafter, a plating layer is formed in the via hole and on the substrate surface by electroless copper plating and electrolytic copper plating, the lower layer and the plating layer are electrically connected through the via, and the plating layer is etched to a predetermined level. A conductor pattern was formed to produce a multilayer printed wiring board with a built-in resistance element having a built-in resistor in the inner layer.

  After degreasing and cleaning the 0.6mm thick BT resin double-sided copper-clad laminate (Mitsubishi Gas Chemical Co., Ltd.) with a copper thickness of 18μm, the etching resist is laminated, exposed and developed, and the copper foil in unnecessary portions is etched. Thus, a first electrode including a conductor circuit and a resistor electrode was formed. At this time, the width of the resistor electrode was 400 μm. A conductive silver paste XA-436 (manufactured by Fujikura Kasei Co., Ltd.) was screen printed on the remaining 300 μm area on the remaining 300 μm area on the resistor electrode thus formed. Next, after drying and curing, a second electrode of silver paste was formed. When the film thickness of the second electrode of the silver paste was measured, the film thickness was about 12 μm. A carbon paste dotite R-121 (manufactured by Fujikura Kasei Co., Ltd.) was screen-printed on the first electrode including the resistor electrode on which the second electrode of the silver paste was formed. Next, when the film thickness of the carbon paste resistor was measured after drying and curing, the film thickness was about 15 μm. Next, build-up insulating resin ABF-GX (manufactured by Ajinomoto Fine Techno Co., Ltd.) was laminated on this substrate with a vacuum pressure laminator and cured in a hot air oven at 170 ° C. for 1 hour. After drilling the via holes with a CO2 laser, electroless plating and electrolytic copper plating are performed, vias and plating layers are formed in the via holes and on the substrate surface, and the lower and upper plating layers are connected via the vias. Connected electrically. Thereafter, a predetermined conductor pattern was formed by etching the plating layer, and a multilayer printed wiring board with a built-in resistance element having a built-in resistor in the inner layer was manufactured.

  Below, the Example 3 and Example 4 which were implemented as a comparative example are described.

  After degreasing and cleaning the 0.6mm thick BT resin double-sided copper-clad laminate (Mitsubishi Gas Chemical Co., Ltd.) with a copper thickness of 18μm, the etching resist is laminated, exposed and developed, and the copper foil in unnecessary portions is etched. The first electrode including the conductor circuit and the resistor electrode was formed. At this time, the width of the resistor electrode was 200 μm. A conductive silver paste LS-504J (manufactured by Asahi Chemical Research Laboratories) is coated on the resistor electrode so as to cover the entire width of 200 μm on the resistor electrode, and the substrate inside the electrode is further covered. Screen-printed over 400 μm on the insulating resin. Next, after drying and curing, a second electrode of silver paste was formed. When the film thickness of the second electrode of the silver paste was measured, the film thickness was about 15 μm. Carbon paste TU-100-8 (manufactured by Asahi Chemical Laboratory Co., Ltd.) was screen-printed so as to overlap the innermost 200 μm portion of the second electrode of the silver paste thus formed. Next, when the film thickness of the carbon paste resistor was measured after drying and curing, the film thickness was about 20 μm. An insulating layer, a conductor circuit, and the like were formed on this substrate in the same manner as in the manufacturing method of Example 1, and a multilayer printed wiring board with a built-in resistance element having a built-in resistor in the inner layer was manufactured.

After degreasing and cleaning the substrate on a 0.6mm thick BT resin double-sided copper-clad laminate (Mitsubishi Gas Chemical Co., Ltd.) with a copper thickness of 18μm, the etching resist is laminated, exposed and developed, and the copper foil in unnecessary portions is etched Thus, a first electrode including a conductor circuit and a resistance electrode was formed. At this time, the width of the resistor electrode was 400 μm. A conductive silver paste LS-504J (manufactured by Asahi Chemical Research Laboratories) was screen-printed over the entire resistor electrode over 400 μm on the resistor electrode thus formed. Next, after drying and curing, a second electrode of silver paste was formed. When the film thickness of the second electrode of the silver paste was measured, the film thickness was about 15 μm. A carbon paste TU-100-8 (manufactured by Asahi Chemical Research Laboratories) was screen-printed on the second electrode on which the second electrode of the silver paste was thus formed. Next, a resistor was formed after drying and curing. When the film thickness of the carbon paste resistor was measured, the film thickness was about 20 μm. An insulating layer, a conductor circuit, and the like were formed on this substrate in the same manner as in the manufacturing method of Example 1, and a multilayer printed wiring board with a built-in resistance element having a built-in resistor in the inner layer was manufactured. The characteristics of 100 built-in resistance elements in Examples 1 to 4 were evaluated below. The evaluation results are shown in Table 1 below.

なお、評価方法は、上述した方法に準じる。

In addition, the evaluation method is based on the method mentioned above.

  According to Table 1, Example 1 and Example 2 manufactured by the method of the present invention showed good results in resistance value variation, resistance value change, and defect rate.

It is the elements on larger scale of the multilayer printed wiring board incorporating the resistive element of this invention, a is a sectional side view, b is a top view, c is a top view explaining arrangement | positioning of each component. It is a side cross-sectional process drawing of the manufacturing method of the multilayer printed wiring board which incorporated the resistive element of this invention. It is the elements on larger scale of the multilayer printed wiring board incorporating the conventional resistive element, a is a sectional side view, b is a top view. It is the elements on larger scale of the multilayer printed wiring board incorporating the conventional resistive element, a is a sectional side view, b is a top view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Copper foil 10 ... The board | substrate of a core board | substrate, the board | substrate of a single-sided copper clad laminated board, the board | substrate 2 ... Copper foil 20 ... Conductor wiring layer 21 ... 1st electrode 29 ... 1st electrode formation area 22 ... Resistor electrode 30 ... Photosensitivity Resist 40 ... second electrode 45 (of silver paste) ... second electrode formation prohibition region 49 ... second electrode formation region 50 ... resistor 59 ... resistor formation region 6 ... insulating resin layer 60 ... build-up insulating resin 70 ... via Hole 71 ... via 8 ... plated conductor layer 80 (electroless copper plating, electrolytic copper plating) ... wiring pattern 100 ... multilayer printed wiring board with built-in resistance element

Claims (7)

  In a resistance element in which a resistor is formed between a pair of first electrodes formed on an insulating layer, the first electrode has a size not larger than the first electrode at a position not covering the inner end portion. A second electrode is provided, and between the pair of electrodes of the first electrode and the second electrode and the other first electrode and the second electrode, both ends are in contact with the inner end of each first electrode and the second electrode. A resistance element provided with a resistor as described above.   The resistance element according to claim 1, wherein the inner end portion of the first electrode is provided at a position having a length of 50 to 200 μm.   The resistance element according to claim 1, wherein an inner end portion of the first electrode is thinner than other portions of the first electrode.   The resistance element according to claim 1, wherein the resistor is made of a resistance paste.   The resistance element according to claim 1, wherein the second electrode is made of a noble metal.   6. The resistance element according to claim 1, wherein the first electrode is a part of a conductor layer constituting a multilayer printed wiring board.   A multilayer printed wiring board comprising the resistance element according to any one of claims 1 to 6.

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