JP2004235403A

JP2004235403A - Composite electronic component

Info

Publication number: JP2004235403A
Application number: JP2003021821A
Authority: JP
Inventors: Minehiro Itagaki; 峰広板垣; Fusako Hatano; 惣子幡野; Takashi Miyatake; 隆宮武
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-01-30
Filing date: 2003-01-30
Publication date: 2004-08-19

Abstract

<P>PROBLEM TO BE SOLVED: To provide the high connecting reliability of an electronic component such as a resistor, a capacitor, an inductor, etc. in a composite electronic component with resin-molded sheath. <P>SOLUTION: The composite electronic component has the structure that the electronic component 14 is mounted on a substrate 11 via a conductive connecting member 15 and the electronic component 14 is resin-molded with an inorganic filling material 17 and a protective film 16 containing a resin. In the composite electronic component, the concentration of the inorganic filling material 17 in the protective film 16 on the periphery of the electronic component 14 is higher than that of the inorganic filling material 17 of the protective film 16 filled in the gap between the substrate 11 and the electronic component 14. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、複合電子部品に関するものである。
【０００２】
【従来の技術】
以下、従来の複合電子部品について、図面を参照しながら説明する。
【０００３】
図２は従来の複合電子部品の断面図である。
【０００４】
図２において、１はＡｇ，Ｃｕなどの金属からなる導体層（本図では図示せず。）とセラミック層（本図では図示せず。）とを交互に積層して作製し内部に回路パターン（本図では図示せず。）を構成した積層セラミック製の基板である。２は基板１の内部の回路パターンと接続し、基板１の上面に配置した上面電極で、Ａｇ，Ｃｕなどの金属からなる。３は基板１の内部の回路パターンと接続し、複合電子部品の外部出力端子として基板１の下面に配置した下面電極で、Ａｇ，Ｃｕなどの金属からなる。４は上面電極２の上に実装した電子部品であり、例えば抵抗器やコンデンサやインダクタなどである。５は導電性接続部材として電子部品４の端子電極（本図では図示せず。）と基板１の上面電極２とを接合する半田である。６は基板１の電子部品４を実装した面及び電子部品４の外周部をモールドする保護膜であり、７はこの保護膜６の中の無機充填材料である。
【０００５】
なお、この出願の発明に関連する先行技術文献情報としては、特許文献１、特許文献２がある。
【０００６】
【特許文献１】
特開２００２−１９０５６４号公報
【特許文献２】
特開２００２−１９０４９８号公報
【０００７】
【発明が解決しようとする課題】
上記従来の複合電子部品を、長期間放置した後にプリント配線板に実装する場合、保護膜６の樹脂が大気中の水分を吸収し、プリント配線板にリフロー半田付けする時に保護膜６と基板１との間に剥離が生じ、この時に半田５がリフローの熱で流れ出して断線あるいはショートするという課題を有していた。
【０００８】
本発明は上記従来の課題を解決するものであり、保護膜と基板との接合強度の向上した複合電子部品を提供することを目的とするものである。
【０００９】
【課題を解決するための手段】
上記目的を達成するために、本発明は以下の構成を有するものである。
【００１０】
本発明の請求項１に記載の発明は、保護膜を電子部品の周囲の保護膜の中の無機充填材料の濃度が、基板と前記電子部品の隙間の無機充填材料の濃度より高くしたものである。これにより、無機充填材料の濃度を高くした箇所の熱膨張率を基板や電子部品に近づけることができ、接合強度が向上するとともに熱衝撃に対する耐久性が向上し、導電性接続部材を水分から保護できるという作用を有する。
【００１１】
また請求項２に記載の発明は、基板の片面のみを保護膜で封止したものである。これにより、導電性接合部材の周囲の無機充填材料の濃度を高めることによる接合強度が向上するという作用を有する。
【００１２】
また請求項３に記載の発明は、電子部品の周囲の保護膜中の無機充填材料の濃度を８０重量％以上としたものであり、更に接合強度が向上するという作用を有する。
【００１３】
また請求項４に記載の発明は、複合電子部品は基板を内部にコンデンサ部あるいはインダクタ部を含む積層セラミック基板とすることにより、接合強度を向上することができるという作用を有する。
【００１４】
【発明の実施の形態】
以下、本発明の一実施の形態における複合電子部品について、図面を参照しながら説明する。
【００１５】
図１は本発明の一実施の形態における複合電子部品の断面図である。
【００１６】
図１において、１１は導体層（本図では図示せず。）とセラミック層（本図では図示せず。）とを交互に積層して作製し内部に回路パターン（本図では図示せず。）を構成した積層セラミック製の基板である。１２は基板１１の内部の回路パターンと接続し、基板１１の上面に配置した上面電極である。１３は基板１１の内部の回路パターンと接続し、複合電子部品の外部出力端子として基板１１の下面に配置した下面電極である。基板１１の内部各層の回路パターンおよび上面電極１２、下面電極１３は銀を主成分とし、厚みが約２０ミクロンの焼結膜である。上面電極１２および下面電極１３の表面には、下地めっきとしてニッケルメッキやパラジウムメッキなどを施し、その上に金メッキを施した。１４は上面電極１２の上に実装した電子部品であり、例えば１．０ｍｍ×０．５ｍｍサイズの角型積層チップコンデンサおよびダイオードパッケージである。１５は電子部品１４の端子電極（本図では図示せず。）と基板１１の上面電極１２とを接合する導電性接続部材で、半田ペースト［品番ＮＰ３０１−ＧＭ６６５−ＧＫ（株式会社ニホンゲンマ製）］をリフロー半田付けしたものである。１６は基板１１の電子部品１４を実装した面及び電子部品１４の外周部をモールドする保護膜で、モールド用樹脂［品番ＣＶ８５２０Ｃ（松下電工株式会社製）］である。保護膜１６は、樹脂と無機充填材料とを含み、この樹脂はエポキシ系の樹脂である。１７は保護膜１６の中の無機充填材料であり、球状シリカである。この保護膜１６はトランスファモールド工法により形成し、その際、基板１１に搭載した電子部品１４の周囲に無機充填材料１７を、基板１１と電子部品１４との隙間より多く配置するものである。
【００１７】
以上のように構成した複合電子部品について、以下に実装模擬試験後の導通評価および対環境試験後の導通評価について説明する。
【００１８】
実装模擬試験方法は、複合電子部品を長期間放置した後の電子機器への組み込み実装を想定し、８５℃、６０％ＲＨに維持した恒温恒湿槽内に複合電子部品を１６８時間放置した後、リフロー半田付け装置を用いてピーク温度２６０℃、ピーク温度保持時間１０秒間の条件で電子機器の親基板へリフロー半田付けを行った。また導通評価は、実装模擬試験を行った複合電子部品の内部回路パターンの導通を電気テスターで評価した。この評価は、断線またはショートが発生していない複合電子部品を良品とし、断線またはショートが発生した複合電子部品を導通不良とした。ここで比較例として無機充填材料を含有していない保護膜と無機充填材料のシリカをそれぞれ６０重量％、７０重量％、７５重量％含有する保護膜を使用したものを作製し同じ評価を行った。各条件の評価サンプル数は５０個である。その結果を（表１）に示す。
【００１９】
【表１】

【００２０】
（表１）において、シリカを含有していないものと７５重量％以下含有しているものでは導通不良が発生し、８０％以上含有しているものは発生しなかった。導通不良のものを目視観察すると、保護膜と基板との間に亀裂が発生し、導電性接続部材１５である半田の再溶融によるショートを観察した。
【００２１】
次に、対環境試験として複合電子部品の各サンプルを温度サイクル試験槽に供し、−４０℃の環境条件を３０分と、＋８５℃の環境条件を３０分とを１サイクルとし、これを１０００〜２０００サイクル数実施し、このサンプルの基板１１と電子部品１４との導通を電気テスターで評価した。この評価は、断線またはショートが発生していない複合電子部品を良品とし、断線またはショートが発生した複合電子部品を導通不良とした。比較例として保護膜の無機充填材料であるシリカの含有率が６０〜７５重量％の複合電子部品を用いた。各条件の評価サンプル数は５０個である。その結果を（表２）に示す。
【００２２】
【表２】

【００２３】
（表２）において、比較例のシリカ含有率が６０〜７５重量％の保護膜を用いたものは１０００サイクルから１５００サイクルの間で断線不良が発生したが、シリカ含有率が８０％以上のものは２０００サイクル後でも断線は発生しなかった。
【００２４】
【発明の効果】
以上のように本発明は、保護膜の電子部品近傍の無機充填材料の濃度を、基板と電子部品との隙間に位置する無機充填材料の濃度よりも高くすることにより、基板と保護膜との接合強度が向上した複合電子部品を提供することができるという効果を奏する。
【図面の簡単な説明】
【図１】本発明の一実施の形態における複合電子部品の断面図
【図２】従来の複合電子部品の断面図
【符号の説明】
１１基板
１２上面電極
１４電子部品
１５導電性接続部材
１６保護膜
１７無機充填材料[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a composite electronic component.
[0002]
[Prior art]
Hereinafter, a conventional composite electronic component will be described with reference to the drawings.
[0003]
FIG. 2 is a sectional view of a conventional composite electronic component.
[0004]
In FIG. 2, reference numeral 1 denotes a circuit pattern formed by alternately laminating a conductor layer (not shown in this drawing) made of a metal such as Ag or Cu and a ceramic layer (not shown in this drawing) and forming a circuit pattern therein. (Not shown in this figure) is a substrate made of a laminated ceramic. Reference numeral 2 denotes an upper surface electrode connected to a circuit pattern inside the substrate 1 and disposed on the upper surface of the substrate 1 and made of a metal such as Ag or Cu. Reference numeral 3 denotes a lower surface electrode connected to a circuit pattern inside the substrate 1 and disposed on the lower surface of the substrate 1 as an external output terminal of the composite electronic component, and is made of a metal such as Ag or Cu. Reference numeral 4 denotes an electronic component mounted on the upper electrode 2, such as a resistor, a capacitor, or an inductor. Reference numeral 5 denotes a solder as a conductive connection member that joins a terminal electrode (not shown in the figure) of the electronic component 4 and the upper electrode 2 of the substrate 1. Reference numeral 6 denotes a protective film for molding the surface of the substrate 1 on which the electronic component 4 is mounted and the outer peripheral portion of the electronic component 4, and 7 denotes an inorganic filler material in the protective film 6.
[0005]
Prior art document information related to the invention of this application includes Patent Document 1 and Patent Document 2.
[0006]
[Patent Document 1]
JP 2002-190564 A [Patent Document 2]
JP-A-2002-190498
[Problems to be solved by the invention]
When the above-mentioned conventional composite electronic component is mounted on a printed wiring board after being left for a long period of time, the resin of the protective film 6 absorbs moisture in the air, and the protective film 6 and the substrate 1 are reflow soldered to the printed wiring board. At the same time, the solder 5 flows out due to the heat of the reflow, causing a disconnection or a short circuit.
[0008]
An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a composite electronic component having improved bonding strength between a protective film and a substrate.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
[0010]
The invention according to claim 1 of the present invention is such that the concentration of the inorganic filler material in the protective film around the electronic component is higher than the concentration of the inorganic filler material in the gap between the substrate and the electronic component. is there. As a result, the coefficient of thermal expansion of the portion where the concentration of the inorganic filler material is increased can be made closer to the substrate or the electronic component, so that the bonding strength is improved, the durability against thermal shock is improved, and the conductive connecting member is protected from moisture. Has the effect of being able to.
[0011]
According to a second aspect of the present invention, only one surface of the substrate is sealed with a protective film. This has the effect of improving the bonding strength by increasing the concentration of the inorganic filler material around the conductive bonding member.
[0012]
The third aspect of the present invention is that the concentration of the inorganic filler material in the protective film around the electronic component is set to 80% by weight or more, and has an effect of further improving the bonding strength.
[0013]
Further, the invention described in claim 4 has an effect that the bonding strength can be improved by using the composite electronic component as a multilayer ceramic substrate including a capacitor portion or an inductor portion inside the substrate.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a composite electronic component according to an embodiment of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 is a sectional view of a composite electronic component according to an embodiment of the present invention.
[0016]
In FIG. 1, reference numeral 11 denotes a circuit pattern (not shown in this figure) which is produced by alternately laminating a conductor layer (not shown in this figure) and a ceramic layer (not shown in this figure). ) Is a substrate made of a laminated ceramic. Reference numeral 12 denotes an upper surface electrode connected to a circuit pattern inside the substrate 11 and arranged on the upper surface of the substrate 11. Reference numeral 13 denotes a lower surface electrode connected to a circuit pattern inside the substrate 11 and arranged on the lower surface of the substrate 11 as an external output terminal of the composite electronic component. The circuit pattern of each layer inside the substrate 11 and the upper electrode 12 and the lower electrode 13 are sintered films having silver as a main component and a thickness of about 20 microns. The surfaces of the upper electrode 12 and the lower electrode 13 were subjected to nickel plating, palladium plating, or the like as base plating, and gold plating was applied thereon. Reference numeral 14 denotes an electronic component mounted on the upper electrode 12, for example, a rectangular multilayer chip capacitor of 1.0 mm × 0.5 mm and a diode package. Reference numeral 15 denotes a conductive connection member that joins a terminal electrode (not shown in the figure) of the electronic component 14 and the upper surface electrode 12 of the substrate 11, and is a solder paste [part number NP301-GM665-GK (manufactured by Nihon Genma Co., Ltd.)]. Is reflow soldered. Reference numeral 16 denotes a protective film for molding the surface of the substrate 11 on which the electronic component 14 is mounted and the outer peripheral portion of the electronic component 14, and is a molding resin [CV8520C (manufactured by Matsushita Electric Works, Ltd.)]. The protective film 16 includes a resin and an inorganic filling material, and the resin is an epoxy resin. Reference numeral 17 denotes an inorganic filler material in the protective film 16, which is spherical silica. The protective film 16 is formed by a transfer molding method. In this case, the inorganic filler material 17 is disposed around the electronic component 14 mounted on the substrate 11 in a larger amount than the gap between the substrate 11 and the electronic component 14.
[0017]
The continuity evaluation after the mounting simulation test and the continuity evaluation after the environmental test of the composite electronic component configured as described above will be described below.
[0018]
The mounting simulation test method is based on the assumption that the composite electronic component is mounted in an electronic device after being left for a long period of time, and after leaving the composite electronic component in a thermo-hygrostat maintained at 85 ° C. and 60% RH for 168 hours. Using a reflow soldering apparatus, reflow soldering was performed on the parent substrate of the electronic device under the conditions of a peak temperature of 260 ° C. and a peak temperature holding time of 10 seconds. In the conduction evaluation, the conduction of the internal circuit pattern of the composite electronic component subjected to the mounting simulation test was evaluated by an electric tester. In this evaluation, a composite electronic component in which a disconnection or a short circuit did not occur was regarded as a non-defective product, and a composite electronic component in which a disconnection or a short circuit occurred occurred was regarded as a poor conduction. Here, as a comparative example, a protective film containing no inorganic filler material and a protective film containing 60% by weight, 70% by weight, and 75% by weight of silica as the inorganic filler material were produced, and the same evaluation was performed. . The number of evaluation samples under each condition is 50. The results are shown in (Table 1).
[0019]
[Table 1]

[0020]
In Table 1, conduction failure occurred in those containing no silica and those containing 75% by weight or less, and those containing 80% or more did not occur. When visually inspecting the conductive failure, a crack was generated between the protective film and the substrate, and a short circuit due to re-melting of the solder as the conductive connection member 15 was observed.
[0021]
Next, each sample of the composite electronic component was subjected to a temperature cycle test tank as an environmental test, and the environmental conditions of −40 ° C. for 30 minutes and the environmental conditions of + 85 ° C. for 30 minutes were defined as one cycle. After 2000 cycles, the electrical continuity between the substrate 11 and the electronic component 14 of this sample was evaluated using an electric tester. In this evaluation, a composite electronic component in which a disconnection or a short circuit did not occur was regarded as a non-defective product, and a composite electronic component in which a disconnection or a short circuit occurred occurred was regarded as a poor conduction. As a comparative example, a composite electronic component having a silica content of 60 to 75% by weight as an inorganic filler material for the protective film was used. The number of evaluation samples under each condition is 50. The results are shown in (Table 2).
[0022]
[Table 2]

[0023]
In Table 2, in the comparative example using the protective film having a silica content of 60 to 75% by weight, a disconnection failure occurred between 1000 cycles and 1500 cycles, but the silica content was 80% or more. No disconnection occurred after 2000 cycles.
[0024]
【The invention's effect】
As described above, the present invention increases the concentration of the inorganic filler material in the vicinity of the electronic component in the protective film to be higher than the concentration of the inorganic filler material located in the gap between the substrate and the electronic component. There is an effect that a composite electronic component with improved bonding strength can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a composite electronic component according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a conventional composite electronic component.
DESCRIPTION OF SYMBOLS 11 Substrate 12 Top electrode 14 Electronic component 15 Conductive connection member 16 Protective film 17 Inorganic filling material

Claims

A substrate having a circuit pattern therein and having an external output terminal electrically connected to the circuit pattern, an electronic component electrically connected to the circuit pattern on the substrate, and at least the external output terminal A protective film including a resin covering the electronic component and an inorganic filler material, wherein the protective film reduces the concentration of the inorganic filler material in the vicinity of the electronic component and the inorganic filler material located in a gap between the substrate and the electronic component. Composite electronic components that are higher than the concentration of

The composite electronic component according to claim 1, wherein the protective film seals only a surface of the substrate having the electronic component.

The composite electronic component according to claim 1, wherein the concentration of the inorganic filler material in the protective film is 80% by weight or more in the vicinity of the electronic component.

The composite electronic component according to claim 1, wherein the substrate is a multilayer ceramic substrate including a capacitor portion or an inductor portion in an internal circuit pattern.