JP3739830B2 - Chip-shaped electronic component and manufacturing method thereof - Google Patents

Description

【００２０】
（表１）より、本発明品は従来品より優れた抵抗値分布を有している。すなわち抵抗トリミング後の抵抗値シフトが極めて少ないことが分かる。
【００２１】
また、本発明品は従来品（銀系厚膜電極品）と比べほぼ同等以上の引張強度を有し、従来の銀系樹脂電極品による比較品と比べて強い引張強度を有していることがわかる。なお、本発明の上記実施例において側面電極層３の金属粉にはニッケル粉や銅粉を用いたが本発明における側面電極層３の金属粉の材質としてはこれに限られるものではない。例えばＡｕ，Ａｇ，Ｐｄなどの貴金属、Ｆｅ，Ａｌ，Ｓｎ，Ｚｎなどの卑金属、あるいは実施例１にあるような表面に異種金属を被覆した複合金属粉などが適用可能である。
【００２２】
また金属粉の大きさは基本的に最大粒径１００μｍ以下であれば構わないが、好ましくは平均粒径２〜１５μｍのものが用いられる。さらに金属粉の形状は問わないが粉体表面に凹凸突起のあることが必要である。凹凸突起の大きさ及びその分布状態の大小は粉体の体積換算の比表面積（比表面積×真比重）で表されるが、上記実施例１、２品ではこの値が１．２〜７（ｍ²／ｃｍ³）のものが適していた。
【００２３】
また側面電極層３に用いられる導電粉は上記金属粉を全導電粉の５０％以上含む。上記の表面に突起を有する金属粉以外の導電粉としては材質に制限はなく、通常導電性ペースト材料に用いられるものが使用可能である（金属粉に限らず導電性セラミック粉、カーボン粉などでも可）。ただし、これらは必須成分ではなく必要に応じて用いられる。
【００２４】
なお、この実施例１、２において側面電極層３のバインダにはレゾール系フェノール樹脂を用いたが、はんだ濡れ性および電気メッキ性を阻害せず、十分低い導体抵抗を確保できればノボラック、アラルキルのような高耐熱のフェノール樹脂やイミド系、エポキシ系の樹脂あるいはこれら樹脂の共重合物、変成物でも可能である。但し、樹脂の特性上フェノール系樹脂が前出特性を満足する上では最も適当であった。
【００２５】
また、保護層６としてエポキシ系樹脂を用いたが、その他の密閉性に優れた樹脂（ポリイミド系、アクリル系等）でも可能であるし、ガラスを保護層として用いた場合でも、抵抗値分布（３σ／平均抵抗値）は０．５％程度になり従来の厚膜サーメット電極品よりも分布が小さくなるという効果を確認している（この場合にはレーザートリミング前にプリコートガラスの印刷・焼成が必要となる。）。
【００２６】
また、実施例１ではんだコート層７は、２３０℃１０秒間のはんだ浸漬により形成したが、これは、スズあるいははんだを主成分とするペーストの材料を、側面電極層３を覆うようにディップあるいは転写印刷し、２００℃〜２８０℃の雰囲気中で熱処理することにより形成しても同等の性能が得られることを確認している。また、大量のチップ状電子部品にコートする場合には電解メッキ工法によりはんだコート層を形成する工法がコスト的にも有利である。
【００２７】
【発明の効果】
以上の説明から明らかなように本発明では、導電性材料として複数個の突起を有する導電性金属粉と樹脂バインダーとを混合した導電性ペーストを塗布硬化した電極層と、この電極層の上に第２層として設けたスズコート層あるいは、はんだコート層とにより外部電極を構成するものであるので、低温度の熱処理で強度の強い外部電極を形成でき、したがって熱処理による電気的特性変化が少なく、製造歩留を向上することができる。
【図面の簡単な説明】
【図１】本発明の実施例１の角形チップ抵抗器の構造を示す斜視図
【図２】本発明の実施例１の角形チップ抵抗器の構造を示す断面図
【図３】本発明の実施例２の角形チップ抵抗器の構造を示す斜視図
【図４】本発明の実施例２の角形チップ抵抗器の構造を示す断面図
【図５】引張試験方法を説明する斜視図
【図６】本発明品の樹脂電極の模式断面図
【図７】従来の角形チップ抵抗器の構造を示す斜視図
【図８】従来の角形チップ抵抗器の構造を示す断面図
【符号の説明】
１ アルミナ基板
２ 上面電極層
３ 側面電極層
３ａ 導電性金属粉
３ｂ 樹脂バインダー
４ 抵抗層
６ 保護層
７ はんだコート層
８ ニッケルコート層[0001]
[Industrial application fields]
The present invention relates to a chip-shaped electronic component such as a chip resistor or a chip capacitor, and a manufacturing method thereof.
[0002]
[Prior art]
In recent years, with the increasing demand for lighter, thinner, and smaller electronic devices, very small electronic components have come to be used in many cases in order to increase the wiring density of circuit boards.
[0003]
An example of the structure of a square chip resistor among conventional chip-shaped electronic components will be described and described. 7 is a perspective view, and FIG. 8 is a cross-sectional view.
[0004]
The conventional square chip resistor is connected to the 96% alumina substrate 10, a pair of upper surface electrode layers 11 formed of a pair of silver-based cermet thick film electrodes formed on the alumina substrate 10, and the upper surface electrode layer 11. The formed resistance layer 12 is formed of a ruthenium-based thick film resistor, the protective layer 14 is made of glass that completely covers the resistance layer 12, and the side electrode layer 13 is formed of a silver-based cermet thick film that overlaps a part of the upper surface electrode layer 11. ing. A nickel plating layer 15 and a solder plating layer 16 are formed on the exposed electrode surface to ensure solderability, thereby forming an external electrode. Other conventional examples include a method of forming an end face electrode with a silver-based cermet thick film and a Ni-Cr-based thin film electrode by a sputtering method aiming at low temperature processing, or a conductive metal powder such as copper powder or silver. There is also a method in which a conductive resin mixed with a binder such as an epoxy resin or a phenol resin is used.
[0005]
[Problems to be solved by the invention]
However, since the side electrode layer 13 of this square chip resistor is formed by baking a silver-based cermet thick film paste at a temperature of about 600 ° C., a gap between the pair of side electrode layers 13 formed before the side electrode formation is formed. The resistance value changes due to the thermal effect of the resistance layer 12. This change in resistance value is a major factor that deteriorates the manufacturing yield of precision (± 1%, ± 0.5%) grade square chip resistors, which have become increasingly popular in recent years.
[0006]
The present invention solves such a problem, and an external electrode having a strength equal to or higher than that of a conventional thick film electrode or the like at a low temperature (250 ° C. to 400 ° C.) at which the electrical characteristic value between the external electrodes does not change. The purpose is to form.
[0007]
[Means for Solving the Problems]
In order to achieve this object, the present invention provides a first electrode layer formed by applying and curing a conductive paste in which a conductive metal powder having a plurality of protrusions and a resin binder are mixed as a conductive material. The external electrode is constituted by a tin coat layer or a solder coat layer provided as a second layer on the electrode layer of the first layer.
[0008]
[Action]
In the present invention, by applying a conductive paste in which a conductive material made of metal powder having a plurality of protrusions and a resin binder are mixed and heat-treated at a low temperature of, for example, 150 ° C. to 250 ° C. The filling density of the metal powder is increased by the curing reaction of the resin material, and a strong anchor force is developed between the resin binder and the metal powder surface having the protrusions. For this reason, even if heat treatment is performed at a low temperature, an external electrode having a strength equal to or higher than that of a conventional thick film cermet electrode or the like can be formed. .
[0009]
【Example】
Example 1
Embodiment 1 of the present invention will be described below with reference to FIGS. In this embodiment, a rectangular chip resistor having the largest quantity among chip-shaped electronic components will be described as an example.
[0010]
FIG. 1 is a perspective view showing Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.
[0011]
As shown in FIGS. 1 and 2, the rectangular chip resistor according to the present embodiment includes a 96% alumina substrate 1, a pair of upper surface electrode layers 2 of a silver-based cermet thick film on the alumina substrate 1, and the upper surface electrode layer. 2, a ruthenium thick film resistive layer 4 that overlaps a part of the protective layer 6, a protective layer 6 made of a resin that completely covers the resistive layer 4, and a thickness of 10 to 50 μm that completely covers the upper electrode layer 2. A pair of side electrodes formed by applying and curing a conductive paste in which a mixed powder of copper-based metal powder having warped protrusions and nickel-based metal powder having a plurality of warped protrusions and a thermosetting polymer as a binder are mixed. It comprises a layer 3 and a solder coat layer 7 formed on the exposed portion of the side electrode layer 3. The side electrode layer 3 and the solder coat layer 7 constitute an external electrode.
[0012]
Next, the manufacturing method of Example 1 of the present invention shown in FIGS. 1 and 2 will be described. First, a 96% alumina substrate 1 having excellent heat resistance and insulation was prepared. In order to divide the alumina substrate 1 into strips and individual pieces, grooves for dividing (mold forming at the time of green sheet) are formed. Next, a thick film silver paste is screen-printed and dried on the surface of the alumina substrate 1, and baked in a belt type continuous baking furnace at a temperature of 850 ° C. with a peak time of 6 minutes and an IN-OUT time of 45 minutes. Electrode layer 2 was formed. Next, a thick film resistance paste mainly composed of RuO ₂ is screen-printed so as to overlap a part of the upper electrode layer 2, and a belt type continuous firing furnace is used at a temperature of 850 ° C. for a peak time of 6 minutes and an IN-OUT time. The resistance layer 4 was formed by firing with a profile of 45 minutes. Next, in order to make the resistance value of the resistance layer 4 between the upper surface electrode layers 2 uniform, a part of the resistance layer 4 is cut and broken by laser light to correct the resistance value (L cut, 30 mm / second, 12 KHz, 5W). Subsequently, an epoxy resin paste is screen-printed so as to completely cover the resistance layer 4, and is cured by a belt type continuous curing furnace at a temperature of 200 ° C. with a peak time of 30 minutes and an IN-OUT time of 50 minutes. It hardened | cured and the protective layer 6 was formed. Next, as a preparatory step for forming the external electrode, the alumina substrate 1 is divided into individual pieces, and the portion where the external electrode is formed is exposed.
[0013]
The paste used as the first electrode layer is made of 50% copper-based metal powder having a plurality of wart-shaped protrusions (particle size is about 2 to 30 μm, and the surface is coated with silver having a thickness of 1 μm or less) and a plurality of Three mixed powders of nickel-based metal powder with wart-like protrusions 50% (particle diameter of about 2 to 10 μm, surface coated with silver having a thickness of 1 μm or less) and resol-based phenol resin using butyl carbitol as a solvent The conductive resin paste is kneaded with a roll. This is preliminarily formed on a stainless metal with a film thickness of about 200 μm, and is applied to the side surface of the divided piece of the alumina substrate 1 by the dipping method, and by a belt type continuous far infrared curing furnace, Heat treatment was performed with a temperature profile having a peak time of 160 ° C. for 15 minutes and an IN-OUT time of 40 minutes to form a side electrode layer 3 having a side part thickness of about 30 to 40 μm. A schematic diagram of the cross section after this formation is shown in FIG. It expresses that the conductive metal powder 3a formed on the alumina substrate 1 has a strong anchor effect on the resin binder 3b thermally cured by the wart-like projections. Next, after this was immersed in a flux, a solder coat layer 7 was formed on the side electrode layer 3 through preheating-solder immersion (230 ° C. for 10 seconds). Through the above steps, a rectangular chip resistor according to Example 1 of the present invention was produced.
[0014]
(Example 2)
Next, a second embodiment of the present invention will be described with reference to FIGS. This will also be described by taking as an example a rectangular chip resistor having the largest quantity among chip-like electronic components.
[0015]
3 is a perspective view showing a second embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along the line AA of FIG.
[0016]
3 and 4, the rectangular chip resistor according to the present embodiment includes a 96% alumina substrate 1, a pair of upper surface electrode layers 2 of a silver-based cermet thick film on the alumina substrate 1, and the upper surface electrode layer 2. A ruthenium thick film resistive layer 4 that partially overlaps, a protective layer 6 made of a resin that completely covers the resistive layer 4, and a plurality of wart-shaped 10-50 μm layers that partially overlap the top electrode layer 2 A nickel-based metal powder having protrusions, a pair of side electrode layers 3 coated and cured with a conductive paste mixed with a thermosetting polymer as a binder, and a nickel coat layer formed on an exposed portion of the side electrode layer 3 8 and a solder coat layer 7 thereon.
[0017]
Next, the manufacturing method of Example 2 of the present invention shown in FIGS. 3 and 4 will be described. The top electrode layer 2, the resistance layer 4, and the protective layer 6 are formed on the alumina substrate 1 in the same manner as in the first embodiment. The paste used as the side electrode layer 3 of the first layer is a conductive resin obtained by kneading a nickel powder (average particle size: 5 μm) having a plurality of protrusions and an epoxy-modified phenolic resin in a three-roll using butyl carbitol as a solvent. Leave as a paste. This is coated with a roller, and heat-treated by a belt type continuous far-infrared curing furnace with a temperature profile having a peak time of 160 ° C. for 15 minutes and an IN-OUT time of 40 minutes, and a side electrode having a thickness of about 30 to 40 μm. Layer 3 was formed. Next, as a preparation step for electroplating, the strip-like alumina substrate was divided into individual pieces. Finally, a nickel coat layer 8 was formed on the exposed upper electrode layer 2 and side electrode layer 3 by electroplating, and a solder coat layer 7 was formed thereon. Through the above steps, a square chip resistor according to Example 2 of the present invention was produced.
[0018]
A tensile strength test was performed on a comparative product using the rectangular chip resistor according to Examples 1 and 2 of the present invention, a conventional rectangular chip resistor, and a silver-based cermet thick film electrode and a silver-based resin electrode as side electrodes. Table 1 shows the results of measuring the resistance value distribution (before shipping resistance value selection) of each square chip resistor. In addition, (Table 1) also shows the resistance variation of one lot of finished product production. As shown in the perspective view of FIG. 5, the tensile strength test involves connecting the external electrode of the chip resistor 21 to the metal wires 23 and 24 with the solder 22, fixing the metal wire 23, and pulling the metal wire 24. It is.
[0019]
[Table 1]

[0020]
From Table 1, the product of the present invention has a resistance distribution superior to that of the conventional product. That is, it can be seen that there is very little resistance value shift after resistance trimming.
[0021]
In addition, the product of the present invention has a tensile strength almost equal to or higher than that of the conventional product (silver-based thick film electrode product), and has a stronger tensile strength than the comparative product of the conventional silver-based resin electrode product. I understand. In the above embodiment of the present invention, nickel powder or copper powder is used as the metal powder of the side electrode layer 3, but the material of the metal powder of the side electrode layer 3 in the present invention is not limited to this. For example, a noble metal such as Au, Ag, Pd, a base metal such as Fe, Al, Sn, Zn, or a composite metal powder having a surface coated with a different metal as in the first embodiment is applicable.
[0022]
The size of the metal powder may be basically a maximum particle size of 100 μm or less, but preferably an average particle size of 2 to 15 μm is used. Further, the shape of the metal powder is not limited, but it is necessary that the powder surface has uneven projections. The size of the projections and depressions and the size of the distribution state are represented by the specific surface area of the powder in terms of volume (specific surface area × true specific gravity), but in the above Examples 1 and 2, this value is 1.2 to 7 ( m ² / cm ³ ) was suitable.
[0023]
Moreover, the conductive powder used for the side electrode layer 3 contains the metal powder in an amount of 50% or more of the total conductive powder. The conductive powder other than the metal powder having protrusions on the surface is not limited in material, and those normally used for conductive paste materials can be used (not only metal powder but also conductive ceramic powder, carbon powder, etc. Yes). However, these are not essential components and are used as necessary.
[0024]
In Examples 1 and 2, resol phenolic resin was used as the binder of the side electrode layer 3, but it does not impede solder wettability and electroplating properties, and if it can secure a sufficiently low conductor resistance, such as novolak and aralkyl. It is also possible to use a highly heat-resistant phenolic resin, imide-based or epoxy-based resin, or a copolymer or modified product of these resins. However, the phenolic resin was most suitable for satisfying the above-mentioned characteristics due to the characteristics of the resin.
[0025]
Moreover, although the epoxy resin was used as the protective layer 6, other resins having excellent sealing properties (polyimide type, acrylic type, etc.) can be used. Even when glass is used as the protective layer, the resistance value distribution ( (3σ / average resistance value) is about 0.5%, confirming the effect that the distribution is smaller than that of conventional thick film cermet electrode products (in this case, printing and firing of the pre-coated glass are performed before laser trimming). Required).
[0026]
Further, in Example 1, the solder coat layer 7 was formed by solder immersion at 230 ° C. for 10 seconds. This was done by dip or paste a paste material mainly composed of tin or solder so as to cover the side electrode layer 3. It has been confirmed that equivalent performance can be obtained even if formed by transfer printing and heat treatment in an atmosphere of 200 ° C. to 280 ° C. In addition, when coating a large amount of chip-shaped electronic components, a method of forming a solder coat layer by an electrolytic plating method is advantageous in terms of cost.
[0027]
【The invention's effect】
As is clear from the above description, in the present invention, an electrode layer obtained by applying and curing a conductive paste in which a conductive metal powder having a plurality of protrusions and a resin binder as a conductive material is mixed, and on the electrode layer Since the external electrode is constituted by the tin coat layer or solder coat layer provided as the second layer, a strong external electrode can be formed by a low-temperature heat treatment, and therefore there is little change in electrical characteristics due to the heat treatment, and manufacturing Yield can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the structure of a rectangular chip resistor according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the structure of a rectangular chip resistor according to a first embodiment of the present invention. FIG. 4 is a cross-sectional view showing the structure of a square chip resistor according to Example 2 of the present invention. FIG. 5 is a perspective view illustrating a tensile test method. FIG. 7 is a perspective view showing the structure of a conventional square chip resistor. FIG. 8 is a cross-sectional view showing the structure of a conventional square chip resistor.
DESCRIPTION OF SYMBOLS 1 Alumina substrate 2 Upper surface electrode layer 3 Side electrode layer 3a Conductive metal powder 3b Resin binder 4 Resistance layer 6 Protective layer 7 Solder coat layer 8 Nickel coat layer

Claims (7)

An external electrode is provided on the side surface portion of the chip-shaped electronic component body, and the external electrode is formed of a first layer formed by applying and curing a conductive paste in which a conductive metal powder having a plurality of protrusions and a resin binder are mixed. A chip-like electronic component constituted by an electrode layer and a tin coat layer or a solder coat layer provided as a second layer on the first electrode layer , the surface of the conductive metal powder being thick 50% copper powder having a particle size of about 2 to 30 μm coated with silver having a thickness of 1 μm or less, and 50% nickel powder having a particle size of about 2 to 10 μm having a surface coated with silver having a thickness of 1 μm or less, and Chip-shaped electronic component having a mixed powder having a volume specific surface area of 1.2 to 7 (m ² / cm ³ ), the resin binder being phenol resin, and the external electrode having a tensile strength of about 350 kg / cm □ . An external electrode is provided on the side surface portion of the chip-shaped electronic component body, and the external electrode is formed of a first layer formed by applying and curing a conductive paste in which a conductive metal powder having a plurality of protrusions and a resin binder are mixed. A chip-shaped electronic component comprising an electrode layer and a tin coat layer or solder coat layer provided as a second layer on the first electrode layer, the conductive metal powder having an average particle size of 5 μm In addition, a chip-like electron whose volumetric specific surface area is 1.2 to 7 (m ² / cm ³ ) nickel powder, the resin binder is phenol resin, and the external electrode has a tensile strength of about 340 kg / cm □. parts. The chip-shaped electronic component according to claim 1 or 2, wherein a nickel coat layer is interposed as a third layer between the electrode layers of the first layer and the second layer . A manufacturing method for manufacturing a chip-shaped electronic component according to claim 1 or 2, wherein an external electrode is provided on a side surface of the chip-shaped electronic component main body, and the external electrode is a conductive metal powder having a plurality of protrusions. A first electrode layer formed by applying and curing a conductive paste mixed with a resin binder, and a solder coat layer provided on the first electrode layer, and the solder coat layer. Is formed by dipping into a molten solder bath at 200 ° C. to 250 ° C. A manufacturing method for manufacturing a chip-shaped electronic component according to claim 1 or 2, wherein an external electrode is provided on a side surface of the chip-shaped electronic component main body, and the external electrode is a conductive metal powder having a plurality of protrusions. A first electrode layer formed by applying and curing a conductive paste mixed with a resin binder and a tin coat layer or a solder coat layer provided on the first electrode layer, A method for manufacturing a chip-shaped electronic component, wherein the tin coat layer or the solder coat layer is formed by an electroplating method . A manufacturing method for manufacturing a chip-shaped electronic component according to claim 1 or 2, wherein an external electrode is provided on a side surface of the chip-shaped electronic component main body, and the external electrode is a conductive metal powder having a plurality of protrusions. A first electrode layer formed by applying and curing a conductive paste mixed with a resin binder and a tin coat layer or a solder coat layer provided on the first electrode layer, The tin coat layer or the solder coat layer is formed by subjecting a paste material mainly composed of tin or solder to dip or transfer printing and heat-treating in an atmosphere of 200 ° C. to 280 ° C. . A manufacturing method for manufacturing a chip-shaped electronic component according to claim 1 or 2, wherein an external electrode is provided on a side surface of the chip-shaped electronic component main body, and the external electrode is a conductive metal powder having a plurality of protrusions. A first electrode layer formed by applying and curing a conductive paste mixed with a resin binder, a nickel coat layer provided on the first layer, a tin coat layer provided on the nickel coat layer, or A method for manufacturing a chip-shaped electronic component , comprising a solder coat layer, wherein the nickel coat layer and a tin coat layer or a solder coat layer are formed by an electroplating method .

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