JP2006237268A - Wiring board - Google Patents

Wiring board Download PDF

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JP2006237268A
JP2006237268A JP2005049630A JP2005049630A JP2006237268A JP 2006237268 A JP2006237268 A JP 2006237268A JP 2005049630 A JP2005049630 A JP 2005049630A JP 2005049630 A JP2005049630 A JP 2005049630A JP 2006237268 A JP2006237268 A JP 2006237268A
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metallized conductor
conductor
wiring board
metallized
mass
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Hidetoshi Taki
英俊 滝
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Kyocera Corp
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Kyocera Corp
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<P>PROBLEM TO BE SOLVED: To provide a wiring board which improves the flatness of a metallized conductor and reduce the possibility of peeling of the metallize conductor from an insulating substrate, and which has superior connection reliability and low electric resistance. <P>SOLUTION: The wiring board is provided with: an insulating substrate 1 formed of a glass ceramic sintered body; and a metallized conductor 2 which is formed inside the insulating substrate 1, of which a part is exposed over the surface of the insulating substrate 1, and which contains copper or metallic particulate made mainly of copper. The exposed part of the metallize conductor 2 is electrically connected with an external electric circuit by means of a low-melting-point brazing material. In the metallized conductor, at least the exposed part and the metallic particulate thereunder are spherical, and the average particle size of the metallic particulate is set at 2 to 9 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、配線基板に関するものであり、特に、メタライズ導体の平坦度が高い配線基板に関するものである。   The present invention relates to a wiring board, and more particularly to a wiring board having a high flatness of a metallized conductor.

ＩＣ，ＬＳＩ等の半導体集積回路素子、ＬＤ（半導体レーザ），ＬＥＤ（発光ダイオード），ＰＤ（フォトダイオード），ＣＣＤ，ラインセンサ，イメージセンサ等の光半導体素子、圧電振動子，水晶振動子等の振動子、その他の種々の電子部品が搭載される配線基板として、ガラスセラミック焼結体から成る絶縁基体と、銅または銅を主成分とする合金から成り絶縁基体の表面に形成されたメタライズ導体と、メタライズ導体の表面を被覆するニッケル、金等のめっき層とを具備する構造のものが知られている。   Semiconductor integrated circuit elements such as IC and LSI, LD (semiconductor laser), LED (light emitting diode), PD (photodiode), CCD, line sensor, optical semiconductor element such as image sensor, piezoelectric vibrator, crystal vibrator, etc. As a wiring board on which a vibrator and other various electronic components are mounted, an insulating base made of a glass ceramic sintered body, and a metallized conductor made of copper or an alloy containing copper as a main component and formed on the surface of the insulating base A structure having a plating layer of nickel, gold or the like covering the surface of the metallized conductor is known.

このような配線基板は、メタライズ導体が、低電気抵抗の銅または銅を主成分とする合金から成ることから、メタライズ導体を低電気抵抗とすることができ、搭載される電子部品を外部電気回路と低抵抗で電気的に接続することができる。   In such a wiring board, since the metallized conductor is made of copper having a low electrical resistance or an alloy containing copper as a main component, the metallized conductor can be made to have a low electrical resistance, and the mounted electronic component can be connected to an external electric circuit. Can be electrically connected with low resistance.

絶縁基体の上面等に電子部品が搭載され、電子部品の電極がメタライズ導体とボンディングワイヤや金属バンプ等を介して電気的に接続され電子装置となる。また、メタライズ導体のうち電子部品の電極と接続されない部位の一部が外部電気回路に錫−鉛半田等の低融点ろう材を介して電気的、機械的に接続される。   An electronic component is mounted on the upper surface of the insulating base, and the electrode of the electronic component is electrically connected to the metallized conductor via a bonding wire, a metal bump, or the like to form an electronic device. In addition, a part of the metallized conductor that is not connected to the electrode of the electronic component is electrically and mechanically connected to the external electric circuit via a low melting point brazing material such as tin-lead solder.

メタライズ導体の表面を被覆するめっき層は、メタライズ導体が外気と接触して酸化腐食することを防止することや、メタライズ導体に対する低融点ろう材の濡れ性を良好に確保すること等の機能を有している。   The plating layer covering the surface of the metallized conductor has functions such as preventing the metallized conductor from being oxidized and corroded by contact with outside air, and ensuring good wettability of the low melting point brazing material to the metallized conductor. is doing.

このような配線基板は、例えば、以下のようにして製作される。すなわち、まず、セラミック粉末に適当なガラス粉末を混合した原料粉末を、有機溶剤、バインダとともにシート状に成形してセラミックグリーンシート（グリーンシート）を作製し、次に、銅または銅を主成分とする金属の粉末に有機溶剤、バインダを添加混練して金属ペーストを作製し、この金属ペーストをグリーンシートにスクリーン印刷法で所定のメタライズ導体のパターンに印刷塗布し、このグリーンシートを、必要に応じて複数上下に積層した後、約１０００℃程度の温度で焼成し、次に、この絶縁基体およびメタライズ導体をニッケルや金等のめっき液中に浸漬し、所定のめっき用電流をメタライズ導体の表面に供給してメタライズ導体の表面にめっき層を被着させることにより製作される。なお、焼成の際に、金属ペーストの銅の粉末の間にグリーンシートのガラス成分が溶融して入り込み、このガラス成分を介して金属ペーストがグリーンシートと一体的に焼結（液相焼結）し、メタライズ導体が絶縁基体の表面に接合される。
特開２００３−１３３７４５号公報 特開２００１−２６７７４２号公報 Such a wiring board is manufactured as follows, for example. That is, first, a raw material powder in which an appropriate glass powder is mixed with a ceramic powder is formed into a sheet shape together with an organic solvent and a binder to produce a ceramic green sheet (green sheet), and then copper or copper as a main component. A metal paste is prepared by adding an organic solvent and a binder to the metal powder to be kneaded, and this metal paste is printed and applied to a green sheet in a predetermined metallized conductor pattern by a screen printing method. Then, the insulating base and the metallized conductor are dipped in a plating solution such as nickel or gold, and a predetermined plating current is applied to the surface of the metallized conductor. And a plating layer is deposited on the surface of the metallized conductor. During firing, the glass component of the green sheet melts and enters between the copper powder of the metal paste, and the metal paste is sintered integrally with the green sheet through this glass component (liquid phase sintering). Then, the metallized conductor is bonded to the surface of the insulating substrate.
JP 2003-133745 A JP 2001-267742 A

しかしながら、ガラスセラミック焼結体から成る絶縁基体の表面に銅または銅を主成分とする合金のメタライズ導体を形成した場合、メタライズ導体に用いる銅や合金の融点が比較的低いことから、金属粉末の粒径が過剰に小さい場合には、金属粉末の単位表面積あたりの体積が小さくなって熱容量が小さくなるために焼結が速く進む傾向があり、焼結した金属粉末により、添加された有機溶剤、バインダ等の外部への除去が妨げられ、メタライズ導体内にガス状となって残ってしまう不都合がある。メタライズ導体内にこのようにガスが残ると、この部分が空隙となるとともに部分的に膨張しメタライズ導体表面に突起が出てしまい、メタライズ導体の表面が凸凹になり、これにより電子部品の実装や、ワイヤボンディング圧着ができないという問題や、外部電気回路へ接続されるメタライズ導体の突起により基板が傾いて、低融点ろう材が偏り、実装信頼性が落ちるという問題が誘発される。   However, when a metallized conductor of copper or an alloy containing copper as a main component is formed on the surface of an insulating substrate made of a glass ceramic sintered body, the melting point of copper or alloy used for the metallized conductor is relatively low, so When the particle size is excessively small, the volume per unit surface area of the metal powder is reduced and the heat capacity is reduced, so that the sintering tends to proceed faster. There is an inconvenience that the removal of the binder or the like to the outside is hindered and the gas remains in the metallized conductor. If the gas remains in the metallized conductor in this way, this part becomes a gap and partially expands, and a protrusion is projected on the surface of the metallized conductor, and the surface of the metallized conductor becomes uneven. The problem that wire bonding cannot be performed and the problem that the substrate is inclined by the protrusion of the metallized conductor connected to the external electric circuit, the low melting point brazing material is biased, and the mounting reliability is lowered.

また、金属粉末の粒径が過剰に大きい場合、あるいは形状が針状など、形状が歪な場合、金属粉末の間にガラス成分を十分に入り込ませて焼結させることが難しく、焼結後、金属微粒子の間に空隙が出来易い。このような空隙内にめっき用のめっき液や、めっきの前処理に通常用いられる酸，アルカリ等の腐食性の成分が入り込んだ場合、メタライズ導体を部分的に腐食させることから、メタライズ導体の絶縁基体に対する接合強度が低くなる。そのため、メタライズ導体の露出部を外部電気回路に低融点ろう材を介して接合し電気的に接続すると、接合のための加熱、および絶縁基体と外部電気回路の基板との熱膨張係数の差にともなう熱応力により、メタライズ導体が絶縁基体から剥がれてしまうという問題がある。   In addition, when the particle size of the metal powder is excessively large, or when the shape is distorted, such as a needle shape, it is difficult to sinter the glass component sufficiently between the metal powder, and after sintering, It is easy to form voids between the metal fine particles. Insulation of the metallized conductor is caused by partial corrosion of the metallized conductor when a plating solution for plating or an acid, alkali, or other corrosive component normally used in the plating pretreatment enters the gap. Bond strength to the substrate is lowered. Therefore, if the exposed part of the metallized conductor is joined and electrically connected to the external electrical circuit via a low melting point brazing material, the heating for joining and the difference in thermal expansion coefficient between the insulating base and the substrate of the external electrical circuit There is a problem that the metallized conductor is peeled off from the insulating base due to the accompanying thermal stress.

特に、近年、低融点ろう材として、錫−銀系等の、いわゆる鉛フリー半田が用いられるようになってきており、従来の錫−鉛半田に比べて、鉛フリー半田の半田付け温度が高いために、メタライズ導体を外部電気回路に電気的に接続するときの熱応力も大きくなり、メタライズ導体の剥がれ等といった不具合も発生しやすくなる。   In particular, so-called lead-free solders such as tin-silver based solders have recently been used as low melting point brazing filler metals, and the soldering temperature of lead-free solders is higher than conventional tin-lead solders. Therefore, thermal stress when electrically connecting the metallized conductor to the external electric circuit is increased, and problems such as peeling of the metallized conductor are likely to occur.

また、近年配線基板の小型化の要求が強く、これに伴い、外部電気回路に電気的に接続されるメタライズ導体の露出部の面積の微小化が求められるようになっている。そのため、メタライズ導体と絶縁基体との接合面積は小さくなる傾向にあり、メタライズ導体の剥がれ等の問題はより一層、発生しやすくなっている。   In recent years, there has been a strong demand for downsizing of a wiring board, and accordingly, the area of an exposed portion of a metallized conductor that is electrically connected to an external electric circuit is required to be reduced. Therefore, the joint area between the metallized conductor and the insulating base tends to be small, and problems such as peeling off of the metallized conductor are more likely to occur.

本発明は上述した諸問題に鑑み案出されたもので、その目的は、銅または銅を主成分とする合金から成るメタライズ導体を外部電気回路に低融点ろう材を介して電気的に接続したときに、メタライズ導体が平坦で、且つ、絶縁基体からの剥がれを有効に防止することができる、高信頼性・高品質の配線基板を提供することにある。   The present invention has been devised in view of the above-mentioned problems, and its purpose is to electrically connect a metallized conductor made of copper or a copper-based alloy to an external electric circuit through a low melting point brazing material. In some cases, a highly reliable and high-quality wiring board is provided in which the metallized conductor is flat and can be effectively prevented from peeling from the insulating substrate.

本発明の配線基板は、ガラスセラミック焼結体から成る絶縁基体と、該絶縁基体の内部に形成されるとともに一部が前記絶縁基体の表面に露出した、銅または銅を主成分とする金属微粒子を含むメタライズ導体とを具備してなり、前記メタライズ導体の露出部が低融点ろう材を介して外部電気回路に電気的に接続される配線基板であって、前記メタライズ導体は、少なくとも前記露出部とその直下部に含まれている金属微粒子が球状を成しているとともに、該金属微粒子の平均粒径が２μｍ乃至９μｍに設定されていることを特徴とするものである。   The wiring board of the present invention includes an insulating base made of a glass ceramic sintered body, and metal fine particles mainly formed of copper or copper, which are formed inside the insulating base and partially exposed on the surface of the insulating base. A wiring board in which the exposed portion of the metallized conductor is electrically connected to an external electric circuit through a low melting point brazing material, wherein the metallized conductor includes at least the exposed portion In addition, the metal fine particles contained immediately below are spherical, and the average particle size of the metal fine particles is set to 2 μm to 9 μm.

また、本発明の配線基板は、前記ガラスセラミック焼結体は抗折強度が３３０ＭＰａ以上であることを特徴とするものである。   The wiring board of the present invention is characterized in that the glass ceramic sintered body has a bending strength of 330 MPa or more.

さらに、本発明の配線基板は、前記ガラスセラミック焼結体は縦弾性係数が１６０ＧＰａ以上であることを特徴とするものである。   Furthermore, the wiring board of the present invention is characterized in that the glass ceramic sintered body has a longitudinal elastic modulus of 160 GPa or more.

またさらに、本発明の配線基板は、前記ガラスセラミック焼結体は熱伝導率が４Ｗ／ｍ・Ｋ以上であることを特徴とするものである。   Furthermore, the wiring board of the present invention is characterized in that the glass ceramic sintered body has a thermal conductivity of 4 W / m · K or more.

さらにまた、本発明の配線基板は、前記メタライズ導体は、６〜１６質量％のガラス質を含み、該ガラス質の成分は、ＳｉＯ２が４６．７〜５２．０質量％，Ａｌ２Ｏ３が１７．２〜２３．７質量％，Ｂ２Ｏ３が５．８〜８．３質量％，ＭｇＯが６．０〜９．０質量％，ＢａＯが５．０〜１５．０％，ＣａＯが２．７〜８．０％，ＺｎＯが１．２〜４．７％に設定されていることを特徴とするものである。 Furthermore, in the wiring board according to the present invention, the metallized conductor includes 6 to 16% by mass of vitreous, and the vitreous component is composed of 46.7 to 52.0% by mass of SiO 2 and Al 2 O 3. There 17.2 to 23.7 wt%, B 2 O 3 is 5.8 to 8.3 wt%, MgO is 6.0 to 9.0 mass%, BaO is 5.0 to 15.0%, CaO Is set to 2.7 to 8.0%, and ZnO is set to 1.2 to 4.7%.

さらにまた、本発明の配線基板は、前記金属微粒子の粒径が、最小粒径１μｍ以上、最大粒径２０μｍ以下であることを特徴とするものである。   Furthermore, the wiring board of the present invention is characterized in that the particle size of the metal fine particles is not less than 1 μm and not more than 20 μm.

本発明の配線基板によれば、メタライズ導体は、少なくとも露出部とその直下部に含まれている金属微粒子が球状を成しているとともに、金属微粒子の平均粒径が２μｍ乃至９μｍに設定されていることから、金属微粒子の間を通過させてバインダ等をメタライズ導体外に除去することができる。   According to the wiring board of the present invention, in the metallized conductor, at least the exposed portion and the metal fine particles contained immediately below the sphere are spherical, and the average particle size of the metal fine particles is set to 2 μm to 9 μm. Therefore, the binder and the like can be removed outside the metallized conductor by passing between the metal fine particles.

またこの場合、金属微粒子の平均粒径は２μｍ乃至９μｍであるため、金属微粒子の平均粒径が小さすぎて焼結が速くなりすぎるといった不都合はなく、焼成時に金属粉末（金属微粒子）の間を通過してバインダを外部にスムーズに除去することができる。   In this case, since the average particle diameter of the metal fine particles is 2 μm to 9 μm, there is no inconvenience that the average particle diameter of the metal fine particles is too small and the sintering becomes too fast. The binder can be smoothly removed through the outside.

これにより、少なくとも露出部において、メタライズ導体の表面の凹凸を防止し、電子部品の実装や、ワイヤボンディング圧着、外部電気回路への接続等を良好に行なわせることができる。   Thereby, the unevenness | corrugation of the surface of a metallized conductor can be prevented at least in an exposed part, and an electronic component can be mounted, wire bonding crimping, connection to an external electric circuit, etc. can be performed satisfactorily.

また、金属微粒子の粒径が大きすぎず、形状が球状であり、密に充填することが可能であるため、金属微粒子の間に十分にガラス成分を入り込ませることができる。これにより、金属微粒子の間に空隙が残留するのを抑制することができるとともに、金属微粒子間にめっき液等が浸入するのを有効に防止することができ、メタライズ導体を腐食の殆どない良好な状態に保つことができる。   Moreover, since the particle size of the metal fine particles is not too large and the shape is spherical and can be densely packed, the glass component can be sufficiently introduced between the metal fine particles. As a result, it is possible to prevent the voids from remaining between the metal fine particles, and to effectively prevent the plating solution or the like from entering between the metal fine particles. Can be kept in a state.

したがって、銅または銅を主成分とする金属微粒子を含むメタライズ導体を外部電気回路に低融点ろう材を介して電気的に接続した場合でも、メタライズ導体の剥がれを有効に防止することができ、高信頼性・高品質の配線基板を提供することができる。   Therefore, even when a metallized conductor containing copper or a metal fine particle mainly composed of copper is electrically connected to an external electric circuit via a low melting point brazing material, peeling of the metallized conductor can be effectively prevented. A reliable and high-quality wiring board can be provided.

また、本発明の配線基板によれば、ガラスセラミック焼結体の抗折強度を３３０ＭＰａ以上に設定することにより、ガラスセラミック焼結体から成る絶縁基体の機械的な強度を十分に高く確保することができ、絶縁基体にクラック等の機械的な破壊が生じることを防止して、より一層、絶縁基体に電子部品を気密封止する場合の信頼性に優れた配線基板とすることができる。   Moreover, according to the wiring board of the present invention, the mechanical strength of the insulating substrate made of the glass ceramic sintered body can be secured sufficiently high by setting the bending strength of the glass ceramic sintered body to 330 MPa or more. Therefore, mechanical breakdown such as cracks can be prevented from occurring in the insulating base, and a wiring board having excellent reliability when the electronic component is hermetically sealed on the insulating base can be obtained.

例えば、絶縁基体に凹部を形成するとともにその凹部を取り囲む絶縁基体の上面に枠状にメタライズ導体を露出させ、凹部内に電子部品を搭載し、金属製の蓋体をシームウェルド法等により絶縁基体上面のメタライズ導体の露出部に接合して凹部を塞ぎ、電子部品を気密封止する際に生じる、金属製の蓋体と絶縁基体との熱膨張係数の違いによる応力や、気密封止された配線基板を外部回路基板に実装する際に生じる、配線基板と外部回路基板との熱膨張係数の違いによる応力等の、大きな応力が絶縁基体に作用したとしても、その応力で絶縁基体にクラック等の機械的な破壊が生じることは有効に防止される。従って、気密封止の信頼性に優れた配線基板が得られる。   For example, a concave portion is formed in the insulating base, and a metallized conductor is exposed in a frame shape on the upper surface of the insulating base surrounding the concave portion, an electronic component is mounted in the concave portion, and a metal lid is insulated by a seam weld method or the like. Bonded to the exposed part of the metallized conductor on the upper surface to close the recess, and the stress caused by the difference in thermal expansion coefficient between the metal lid and the insulating base, which is generated when the electronic component is hermetically sealed, is hermetically sealed Even if a large stress acts on the insulating substrate, such as a stress caused by the difference in thermal expansion coefficient between the wiring substrate and the external circuit substrate, which occurs when the wiring substrate is mounted on the external circuit substrate, the stress may cause cracks in the insulating substrate. It is effectively prevented that the mechanical destruction of is caused. Therefore, a wiring board having excellent hermetic sealing reliability can be obtained.

さらに、本発明の配線基板によれば、ガラスセラミック焼結体の縦弾性係数を１６０ＧＰａ以上に設定しておくことにより、絶縁基体に熱応力等の応力が作用したとしても、その応力で絶縁基体が変形するのを有効に防止することができ、信頼性に優れた配線基板が得られるようになる。例えば、電子部品を内部に搭載し、金属製の蓋体によりシームウェルド法等により、電子部品を気密封止する際に生じる、金属製の蓋体と絶縁基体との熱膨張係数の違いによる応力を受けても、配線基板の弾性変形が有効に防止され、搭載された電子部品の変形に起因した機能の変化や蓋体の反りによる応力の影響を殆ど受けることのない高信頼性の配線基板となすことができる。   Furthermore, according to the wiring board of the present invention, by setting the longitudinal elastic modulus of the glass ceramic sintered body to 160 GPa or more, even if a stress such as a thermal stress acts on the insulating base, the insulating base is affected by the stress. Can be effectively prevented from being deformed, and a highly reliable wiring board can be obtained. For example, the stress caused by the difference in thermal expansion coefficient between the metallic lid and the insulating base, which occurs when the electronic component is mounted inside and the electronic lid is hermetically sealed by the seam weld method, etc. Highly reliable wiring board that is effectively prevented from elastic deformation of the wiring board and hardly affected by stress caused by deformation of the mounted electronic components and warping of the lid Can be

またさらに、本発明の配線基板によれば、ガラスセラミック焼結体の熱伝導率を４Ｗ／ｍ・Ｋ以上に設定しておくことにより、電子部品の発した熱を、絶縁基体を通して効率よく外部へ放散することができ、電子部品の過熱を有効に防止して、より一層優れた信頼性を有する配線基板となすことができる。   Furthermore, according to the wiring board of the present invention, by setting the thermal conductivity of the glass ceramic sintered body to 4 W / m · K or more, the heat generated by the electronic component can be efficiently passed through the insulating substrate. Therefore, the electronic component can be effectively prevented from being overheated, and the wiring board can be further improved in reliability.

さらにまた、本発明の配線基板によれば、メタライズ導体にガラス質を６〜１６質量％含有させるとともに、該ガラス質の成分を、ＳｉＯ２が４６．７〜５２．０質量％，Ａｌ２Ｏ３が１７．２〜２３．７質量％，Ｂ２Ｏ３が５．８〜８．３質量％，ＭｇＯが６．０〜９．０質量％，ＢａＯが５．０〜１５．０％，ＣａＯが２．７〜８．０％，ＺｎＯが１．２〜４．７％に設定することが好ましい。これは、ガラス質の含有量が６質量％未満では、個々の金属微粒子の体積および熱容量が小さくなることで、金属微粒子の焼結が速く、バインダ等が残留してメタライズ導体の表面に凹凸を生じやすくなり、１６質量％を超えると、金属微粒子の間が広くなり過ぎてガラス成分を十分に入り込ませることが難しくなって空隙が残留し、めっき液が入り込みやすくなるからである。 Furthermore, according to the wiring board of the present invention, the metallized conductor contains 6 to 16% by mass of vitreous, and the vitreous component contains 46.7 to 52.0% by mass of SiO 2 , Al 2 O. 3 is 17.2 to 23.7% by mass, B 2 O 3 is 5.8 to 8.3% by mass, MgO is 6.0 to 9.0% by mass, BaO is 5.0 to 15.0% by mass, It is preferable to set CaO to 2.7 to 8.0% and ZnO to 1.2 to 4.7%. This is because when the glassy content is less than 6% by mass, the volume and heat capacity of each metal fine particle become small, so that the metal fine particle sinters quickly and the binder or the like remains, causing irregularities on the surface of the metallized conductor. If the amount exceeds 16% by mass, the space between the metal fine particles becomes too wide, and it becomes difficult to allow the glass component to sufficiently enter, leaving voids, and the plating solution easily enters.

また、本発明の配線基板によれば、金属微粒子の粒径を、最小粒径１μｍ以上、最大粒径２０μｍ以下としたことから、極端に粒径の小さい金属微粒子や大きいものが混在することは無く、より一層確実に、密に充填することができるとともに、金属微粒子の間に十分にガラス成分を入り込ませることができる。   In addition, according to the wiring board of the present invention, the metal particles have a minimum particle size of 1 μm or more and a maximum particle size of 20 μm or less. In addition, the glass component can be filled more reliably and densely, and the glass component can be sufficiently introduced between the metal fine particles.

すなわち、極端に粒径の小さい金属微粒子が、焼成中に早期に溶融して、バインダの除去やガラス成分の入り込みの妨げになるようなことをより確実に防止することができる。また、極端に粒径の大きな金属粒子の間に大きな空隙が生じてガラス成分を十分に入り込ませることが難しくなるようなことや、金属微粒子間の焼結性が不十分になるようなことをより確実に防止することができる。   That is, it is possible to more reliably prevent the metal fine particles having an extremely small particle diameter from melting at an early stage during firing and hindering the removal of the binder and the entry of the glass component. In addition, a large void is generated between extremely large metal particles, and it is difficult to allow the glass component to sufficiently enter, or that the sinterability between the metal fine particles is insufficient. It can prevent more reliably.

これにより、金属微粒子の間に空隙が残留するのをさらに有効に防止し、金属微粒子間にめっき液等が浸入することに起因したメタライズ導体の腐食をより確実に防止することができる。   Thereby, it is possible to more effectively prevent the voids from remaining between the metal fine particles, and to more reliably prevent the metallized conductor from being corroded due to the penetration of the plating solution or the like between the metal fine particles.

以上のように、本発明によれば、銅または銅を主成分とする金属微粒子を含むメタライズ導体を外部電気回路に低融点ろう材を介して電気的に接続する場合であっても、メタライズ導体の剥がれを有効に防止し、接続信頼性に優れた低電気抵抗の配線基板を提供することができる。   As described above, according to the present invention, even when a metallized conductor containing copper or metal fine particles mainly composed of copper is electrically connected to an external electric circuit through a low melting point brazing material, the metallized conductor Thus, it is possible to provide a wiring board with low electrical resistance that effectively prevents peeling and has excellent connection reliability.

以下、本発明を添付図面に基づき詳細に説明する。   Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

図１は本発明の配線基板の実施の形態の一例を示す断面図であり、同図において、１は絶縁基体、２はメタライズ導体、３はメタライズ導体の露出部分に被着されためっき層である。これら絶縁基体１やメタライズ導体２によって主に配線基板９が構成されている。   FIG. 1 is a cross-sectional view showing an example of an embodiment of a wiring board according to the present invention, in which 1 is an insulating substrate, 2 is a metallized conductor, and 3 is a plating layer deposited on an exposed portion of the metallized conductor. is there. A wiring substrate 9 is mainly constituted by the insulating base 1 and the metallized conductor 2.

絶縁基体１は、シリカ系、アルミナ系等のガラスセラミック焼結体により形成される。   The insulating substrate 1 is formed of a glass ceramic sintered body such as silica or alumina.

絶縁基体１は、例えばシリカ系のガラスセラミック焼結体から成る場合であれば、酸化カリウム、酸化マグネシウム等のガラス粉末とアルミナ，シリカ等のセラミック粉末等のセラミック粉末等から成る原料粉末を有機溶剤，バインダとともにシート状に成形し複数枚のグリーンシートを得て、これに適当な孔あけ加工を施すとともに上下に積層し、約１０００℃で焼成することにより製作される。   If the insulating substrate 1 is made of, for example, a silica-based glass ceramic sintered body, a raw material powder made of glass powder such as potassium oxide or magnesium oxide and ceramic powder such as ceramic powder such as alumina or silica is used as an organic solvent. , A sheet is formed with a binder to obtain a plurality of green sheets, which are subjected to appropriate perforation processing, stacked up and down, and fired at about 1000 ° C.

絶縁基体１は、ＩＣ，ＬＳＩ等の半導体集積回路素子、ＬＤ（半導体レーザ），ＬＥＤ（発光ダイオード），ＰＤ（フォトダイオード），ＣＣＤ，ラインセンサ，イメージセンサ等の光半導体素子、圧電振動子，水晶振動子等の振動子、その他の種々の電子部品を搭載・支持するための基体として機能し、主面（この例では上面）や側面に電子部品が搭載される。   The insulating substrate 1 is a semiconductor integrated circuit element such as an IC or LSI, an LD (semiconductor laser), an LED (light emitting diode), a PD (photodiode), a CCD, a line sensor, an optical semiconductor element such as an image sensor, a piezoelectric vibrator, It functions as a base for mounting and supporting a vibrator such as a crystal vibrator and other various electronic components, and the electronic components are mounted on the main surface (the upper surface in this example) and side surfaces.

また、絶縁基体１の表面には、メタライズ導体２が形成されている。   A metallized conductor 2 is formed on the surface of the insulating substrate 1.

メタライズ導体２は、例えば、絶縁基体１の電子部品が搭載される主面から他の主面や側面等にかけて形成されており、配線基板９に搭載される電子部品（図示せず）の電極を外部に導出し外部電気回路（図示せず）と電気的に接続する機能をなす。メタライズ導体２の露出部に対する電子部品の電極や外部電気回路との電気的な接続は、ボンディングワイヤや低融点ろう材を介して行われる。なお、メタライズ導体２は、絶縁基体１の内部にも形成してもよい。   The metallized conductor 2 is formed from, for example, a main surface on which the electronic component of the insulating base 1 is mounted to another main surface or side surface, and an electrode of an electronic component (not shown) mounted on the wiring board 9 is used. It functions to lead out and to be electrically connected to an external electric circuit (not shown). The electrical connection between the exposed portion of the metallized conductor 2 and the electrode of the electronic component or an external electric circuit is performed through a bonding wire or a low melting point brazing material. The metallized conductor 2 may also be formed inside the insulating base 1.

メタライズ導体２は、銅または銅を主成分とする金属微粒子を含んで形成されている。銅を主成分とする合金としては、銅に銀、金、チタン等の金属成分を添加した合金が用いられる。   The metallized conductor 2 is formed including copper or metal fine particles mainly composed of copper. As an alloy containing copper as a main component, an alloy obtained by adding a metal component such as silver, gold, or titanium to copper is used.

このメタライズ導体２は、例えば、銅または銅を主成分とする合金（混合物）の金属微粒子を、有機溶剤，バインダとともに混練して作製した金属ペーストをグリーンシートの表面に印刷塗布しておくことにより形成される。   For example, the metallized conductor 2 is obtained by printing and applying on a surface of a green sheet a metal paste prepared by kneading copper or an alloy (mixture) containing copper as a main component together with an organic solvent and a binder. It is formed.

また、メタライズ導体２は、その露出表面がめっき層３により被覆される。   Further, the exposed surface of the metallized conductor 2 is covered with the plating layer 3.

めっき層３は、メタライズ導体２が外気と接触して酸化することを防止するとともに、ボンディングワイヤのボンディング性や、低融点ろう材の濡れ性等を向上させる機能をなす。   The plating layer 3 functions to prevent the metallized conductor 2 from being oxidized by contact with the outside air, and to improve the bonding property of the bonding wire, the wettability of the low melting point brazing material, and the like.

このようなめっき層３は、例えば、ニッケルやニッケル−コバルト等のニッケル合金、金、銅、パラジウム、白金等の金属材料により形成されている。   Such a plating layer 3 is formed of, for example, a nickel material such as nickel or nickel-cobalt, or a metal material such as gold, copper, palladium, or platinum.

これらの金属材料から成るめっき層３は、耐食性、半田濡れ性、ボンディング性の観点から、腐食され難く、半田等の低融点ろう材との拡散が速く、硬度が比較的低いことから、ボンディング性が良好である。また、これらの金属材料を複数積層してめっき層を構成しても良く、その場合、金めっき層を最表面に位置させることが好ましい。   The plating layer 3 made of these metal materials is not easily corroded from the viewpoint of corrosion resistance, solder wettability, and bonding properties, and since it diffuses quickly with a low melting point solder such as solder and has a relatively low hardness, Is good. Moreover, a plating layer may be formed by laminating a plurality of these metal materials. In this case, it is preferable to place the gold plating layer on the outermost surface.

また、金めっき層のメタライズ導体２に対する強固な接合強度および、メタライズ導体２に接合される低融点ろう材との強固な接合強度を得るために、低融点ろう材と高強度な合金層を形成するニッケルあるいは銅などのめっきを、メタライズ導体２と金めっき層との間に介在させておいても良い。   Further, in order to obtain a strong bonding strength of the gold plating layer to the metallized conductor 2 and a strong bonding strength with the low melting point brazing material bonded to the metallized conductor 2, a low melting point brazing material and a high strength alloy layer are formed. A plating of nickel or copper to be performed may be interposed between the metallized conductor 2 and the gold plating layer.

このように、めっき層３は、メタライズ導体２の表面から順次被着されたニッケルあるいは銅めっき層および金めっき層により構成することが好ましい。   Thus, the plating layer 3 is preferably composed of a nickel or copper plating layer and a gold plating layer sequentially deposited from the surface of the metallized conductor 2.

なお、めっき層３は、例えば金めっき層の場合であれば、メタライズ導体２が被着された絶縁基体１を、シアン系金化合物を金の供給源として含有し、ｐＨ調整剤、錯化剤等を添加して成る金めっき液中に浸漬するとともに、メタライズ導体２の露出している表面に、めっき用治具等を介して所定の電流を通電することによりメタライズ導体２の表面に形成される。なお、めっきの前処理として、メタライズ導体２に対して、アルカリ脱脂処理や、酸（希塩酸等）による酸処理が施される。   If the plating layer 3 is, for example, a gold plating layer, the insulating substrate 1 to which the metallized conductor 2 is applied is contained as a gold source with a cyan gold compound, and a pH adjuster, complexing agent Is formed on the surface of the metallized conductor 2 by applying a predetermined current to the exposed surface of the metallized conductor 2 through a plating jig or the like. The In addition, as a pretreatment for plating, the metallized conductor 2 is subjected to an alkali degreasing treatment or an acid treatment with an acid (such as dilute hydrochloric acid).

そして、例えば、絶縁基体１の上面等に電子部品を搭載するとともに、電子部品の電極をメタライズ導体２の所定部位にボンディングワイヤや半田等の導電性接続材を介して電気的に接続するとともに、メタライズ導体２のうち、電子部品の電極と接続されない部分の一部を、外部電気回路に低融点ろう材を介して電気的、機械的に接続することにより、メタライズ導体２を介して電子部品が外部電気回路と電気的に接続される。   For example, while mounting an electronic component on the upper surface of the insulating base 1, etc., electrically connecting the electrode of the electronic component to a predetermined portion of the metallized conductor 2 via a conductive connecting material such as a bonding wire or solder, A part of the metallized conductor 2 that is not connected to the electrode of the electronic component is electrically and mechanically connected to the external electric circuit via the low melting point brazing material, so that the electronic component is connected via the metallized conductor 2. It is electrically connected to an external electric circuit.

なお、低融点ろう材としては、錫−鉛（共晶）半田や、錫−銀系、錫−銀−銅系、錫−銀−銅―ビスマス系、錫−銀−銅−亜鉛系等の半田等が用いられる。   The low melting point brazing material includes tin-lead (eutectic) solder, tin-silver, tin-silver-copper, tin-silver-copper-bismuth, tin-silver-copper-zinc, and the like. Solder or the like is used.

また、本形態の配線基板９において、上述したメタライズ導体２は、少なくとも露出部とその直下部において、含まれる銅または銅を主成分とする金属微粒子が球状を成しているとともに、金属微粒子の平均粒径が２乃至９μｍに設定されている。   Further, in the wiring board 9 of the present embodiment, the metallized conductor 2 described above has a spherical shape of metal fine particles containing copper or copper as a main component at least in the exposed portion and immediately below the exposed portion. The average particle size is set to 2 to 9 μm.

メタライズ導体２について、少なくとも露出部とその直下部に含まれる銅または銅を主成分とする金属微粒子を、平均粒径が２乃至９μｍの球状になすことにより、個々の金属粉末（金属微粒子）の単位表面積あたりの体積が大きくなるとともに熱容量が大きくなることから、焼結が速すぎるといったことはなくなり、金属微粒子の間を通過して金属ペースト中の有機溶剤、バインダ等を効率よく金属ペースト（メタライズ導体２）から分解除去することができる。その結果、メタライズ導体に添加された有機溶剤、バインダ等が抜けきらずに、メタライズ導体内にガス状となって残り、この部分が空隙となり焼結後まで中に残り、メタライズ表面に突起が出てしまうといった問題を有効に防止できる。   For the metallized conductor 2, at least the exposed portion and the metal fine particles mainly composed of copper contained immediately below it are formed into a spherical shape having an average particle size of 2 to 9 μm, whereby individual metal powders (metal fine particles) are formed. Since the volume per unit surface area is increased and the heat capacity is increased, the sintering is not too fast, and the metal paste (metallized metal paste) is efficiently passed through the metal fine particles to efficiently remove organic solvents and binders in the metal paste. The conductor 2) can be disassembled and removed. As a result, the organic solvent, binder, etc. added to the metallized conductor are not completely removed, but remain in a gaseous state in the metallized conductor, and this part becomes a void and remains inside after sintering, with protrusions appearing on the metallized surface. Can be effectively prevented.

これにより、メタライズ表面に突起が出ることは効果的に防止され、電子部品の実装や、ワイヤボンディング圧着等を強固に行なわせることができ、接続信頼性を優れたものとすることができる。   Thereby, it is possible to effectively prevent protrusions from appearing on the metallized surface, and it is possible to firmly mount electronic components, wire bonding pressure bonding, and the like, and to have excellent connection reliability.

また、銅粉末の粒径が大きすぎず、形状が球状であるため、密に充填することができ、銅の粉末の間に十分にガラス成分が入り込んで焼結させることができる。そのため、銅の粉末間のガラス成分を介しての焼結性が向上するので、銅粉末間にめっき液等が浸入することは殆どなく、メタライズ導体２の腐食を有効に防止することができる。   Moreover, since the particle size of the copper powder is not too large and the shape is spherical, the copper powder can be filled densely, and the glass component can be sufficiently inserted between the copper powder and sintered. Therefore, since the sinterability through the glass component between the copper powders is improved, the plating solution or the like hardly enters between the copper powders, and corrosion of the metallized conductor 2 can be effectively prevented.

これにより、銅または銅を主成分とする合金から成るメタライズ導体２を外部電気回路に低融点ろう材を介して電気的に接続する場合であっても、メタライズ導体２が絶縁基体１より剥離するといった不具合も有効に防止され、接続信頼性に優れた低電気抵抗の配線基板９を得ることができる。   Accordingly, even when the metallized conductor 2 made of copper or an alloy containing copper as a main component is electrically connected to the external electric circuit via the low melting point brazing material, the metallized conductor 2 is peeled off from the insulating base 1. Such a problem can be effectively prevented, and a low electrical resistance wiring substrate 9 excellent in connection reliability can be obtained.

この場合、メタライズ導体２の露出部は、その直下部の影響を受けて変形等を生じる恐れがあるので、メタライズ導体２に含まれる金属微粒子は、露出部だけでなく、その直下部においても、球状と成すとともに平均粒径を２μｍ乃至９μｍとすることが重要である。   In this case, since the exposed portion of the metallized conductor 2 may be deformed due to the influence of the lower portion thereof, the metal fine particles contained in the metalized conductor 2 are not only exposed but also directly below the exposed portion. It is important to have a spherical shape and an average particle size of 2 to 9 μm.

なお、金属微粒子の平均粒径が２μｍ未満では、個々の金属微粒子の体積および熱容量が小さくなるため、金属微粒子の間にガラス成分が入り込む前に金属微粒子、特に銅成分の溶融等が始まり、バインダ等がメタライズ導体２の露出部やその直下等に残留して表面に凹凸を生じる。また、絶縁基体１と一体的に焼結させることができず、また銅と絶縁基体１との収縮率の不一致により絶縁基体１に反り等の不具合を発生させてしまう。また、９μｍを超えると、金属微粒子の間が広くなり過ぎてガラス成分を十分に入り込ませることが難しくなり、空隙が残留してめっき液が入り込むことに起因する腐食等を生じてしまう。また、金属微粒子が大きくなりすぎて金属微粒子間の焼結性が不十分になり、かえって絶縁基体１に対する接合強度が低くなってしまう。したがって、金属微粒子の平均粒径を２μｍ乃至９μｍの範囲に設定することが重要である。   If the average particle size of the metal fine particles is less than 2 μm, the volume and heat capacity of the individual metal fine particles become small. Therefore, the melting of the metal fine particles, particularly the copper component, starts before the glass component enters between the metal fine particles. And the like remain on the exposed portion of the metallized conductor 2 or directly below the metalized conductor 2 to cause unevenness. Further, it cannot be sintered integrally with the insulating substrate 1, and a defect such as warpage is caused in the insulating substrate 1 due to the mismatch of the shrinkage ratio between the copper and the insulating substrate 1. On the other hand, when the thickness exceeds 9 μm, the space between the metal fine particles becomes too wide to make it difficult for the glass component to sufficiently enter, and the voids remain and corrosion due to the plating solution entering occurs. Further, the metal fine particles become too large, and the sinterability between the metal fine particles becomes insufficient, and on the contrary, the bonding strength to the insulating substrate 1 is lowered. Therefore, it is important to set the average particle size of the metal fine particles in the range of 2 μm to 9 μm.

なお、金属微粒子について、平均粒径が２乃至９μｍの球状とするには、従来周知の水アトマイズ工法等が採用される。   In addition, conventionally well-known water atomization method etc. are employ | adopted in order to make metal fine particles spherical with an average particle diameter of 2 to 9 μm.

また、絶縁基体１を形成するガラスセラミック焼結体の抗折強度は３３０ＭＰａ以上であることが好ましい。かかる構成となすことにより、ガラスセラミック焼結体から成る絶縁基体１の機械的な強度を十分に高く確保することができ、絶縁基体１に電子部品を気密封止する場合の信頼性に優れた配線基板とすることができる。   Moreover, it is preferable that the bending strength of the glass-ceramic sintered compact which forms the insulating base | substrate 1 is 330 Mpa or more. By adopting such a configuration, the mechanical strength of the insulating base 1 made of a glass ceramic sintered body can be secured sufficiently high, and the reliability when the electronic component is hermetically sealed on the insulating base 1 is excellent. It can be set as a wiring board.

例えば、絶縁基体１に凹部（図示せず）を形成するとともに凹部内に電子部品を搭載し、金属製の蓋体（図示せず）をシームウェルド法等により絶縁基体１に接合して凹部を塞ぎ、電子部品を気密封止する際に生じる、金属製の蓋体と絶縁基体１との熱膨張係数の違いによる応力や、気密封止された配線基板９を外部回路基板（図示せず）に実装する際に生じる、配線基板９と外部回路基板との熱膨張係数の違いによる応力等の応力が絶縁基体１に作用したとしても、その応力で絶縁基体１にクラック等の機械的な破壊が生じることは有効に防止される。従って、気密封止の信頼性に優れた配線基板となる。   For example, a recess (not shown) is formed in the insulating base 1 and an electronic component is mounted in the recess, and a metal lid (not shown) is joined to the insulating base 1 by a seam weld method or the like to form the recess. Stress due to the difference in thermal expansion coefficient between the metal lid and the insulating base 1 generated when the electronic component is sealed and the airtight sealing of the electronic component, or the hermetically sealed wiring board 9 is external circuit board (not shown). Even if a stress such as a stress caused by a difference in thermal expansion coefficient between the wiring board 9 and the external circuit board is applied to the insulating base 1 when it is mounted on the insulating base 1, mechanical damage such as a crack is caused on the insulating base 1 by the stress. Is effectively prevented from occurring. Therefore, the wiring board is excellent in hermetic sealing reliability.

なお、ガラスセラミック焼結体から成る絶縁基体１について、その抗折強度を３３０ＭＰａ以上とするには、例えば、２５質量％以上のアルミナ質を含むことが望ましい。   In addition, about the insulating base | substrate 1 which consists of a glass ceramic sintered compact, in order that the bending strength shall be 330 Mpa or more, it is desirable to contain 25 mass% or more of alumina, for example.

また、絶縁基体１を形成するガラスセラミック焼結体の縦弾性係数は１６０ＧＰａ以上であることが好ましい。かかる構成となすことにより、絶縁基体１に熱応力等の応力が作用したとしても、その応力で絶縁基体１が弾性変形することなく、電子部品に変形による機能の変化を起こさせることのない、また、蓋体に反りの応力を与えることのない、より一層信頼性に優れた配線基板９とすることができる。   Moreover, it is preferable that the longitudinal elastic modulus of the glass ceramic sintered body forming the insulating substrate 1 is 160 GPa or more. By adopting such a configuration, even if a stress such as a thermal stress acts on the insulating substrate 1, the insulating substrate 1 is not elastically deformed by the stress, and the electronic component is not changed in function due to the deformation. In addition, the wiring board 9 can be made more highly reliable without giving warping stress to the lid.

例えば、電子部品を内部に搭載し、金属製の蓋体によりシームウェルド法等により、電子部品を気密封止する際に生じる、金属製の蓋体と絶縁基体１との熱膨張係数の違いによる応力を受けても、配線基板９が（弾性）変形することなく、搭載された電子部品に変形からくる機能の変化を起こさせることのない、また、蓋体に反りによる応力を与えることない、より一層信頼性に優れた配線基板９とすることができる。   For example, due to the difference in thermal expansion coefficient between the metal lid and the insulating substrate 1 that occurs when the electronic component is mounted inside and the electronic component is hermetically sealed by a seam weld method or the like with the metal lid. Even if stress is received, the wiring board 9 is not (elastically) deformed, the mounted electronic component is not caused to change its function due to deformation, and the lid is not subjected to stress due to warpage, The wiring board 9 can be made more highly reliable.

なお。絶縁基体１について、その縦弾性係数を１６０ＧＰａ以上とするには、例えば、２５質量％以上のアルミナ質を含むことが望ましい。   Note that. In order for the insulating base 1 to have a longitudinal elastic modulus of 160 GPa or more, for example, it is desirable to include 25 mass% or more of alumina.

また、絶縁基体１を形成するガラスセラミック焼結体の熱伝導率は４Ｗ／ｍ・Ｋ以上であることが好ましい。かかる構成となすことにより、電子部品で発生した熱を、絶縁基体１を通して効果的に外部へ伝導でき、電子部品の過熱を防止して、長期に渡り信頼性に優れた配線基板９となる。   Moreover, it is preferable that the heat conductivity of the glass-ceramic sintered compact which forms the insulation base | substrate 1 is 4 W / m * K or more. With this configuration, the heat generated in the electronic component can be effectively conducted to the outside through the insulating base 1, and the electronic component is prevented from being overheated, so that the wiring substrate 9 is excellent in reliability over a long period of time.

なお、絶縁基体１について、その熱伝導率を４Ｗ／ｍ・Ｋ以上とするには、例えば、２５質量％以上のアルミナ質を含むことが望ましい。   In addition, about the insulating base | substrate 1, in order to make the heat conductivity into 4 W / m * K or more, it is desirable to contain 25 mass% or more of alumina, for example.

また、メタライズ導体２にはガラス質を６〜１６質量％含有させるとともに、該ガラス質の成分を、ＳｉＯ２が４６．７〜５２．０質量％，Ａｌ２Ｏ３が１７．２〜２３．７質量％，Ｂ２Ｏ３が５．８〜８．３質量％，ＭｇＯが６．０〜９．０質量％，ＢａＯが５．０〜１５．０％，ＣａＯが２．７〜８．０％，ＺｎＯが１．２〜４．７％に設定しておくことが好ましい。かかる構成となすことにより、少なくとも露出部において、より一層確実にメタライズ導体の表面に凹凸が生じることが防止された、平坦度が良好に確保された配線基板とすることができる。 In addition, the metallized conductor 2 contains 6 to 16% by mass of glass, and the glassy components are 46.7 to 52.0% by mass of SiO 2 and 17.2 to 23.3% of Al 2 O 3 . 7 wt%, B 2 O 3 is 5.8 to 8.3 wt%, MgO is 6.0 to 9.0 mass%, BaO is 5.0 to 15.0%, CaO is 2.7 to 8. It is preferable to set 0% and ZnO to 1.2 to 4.7%. By adopting such a configuration, it is possible to obtain a wiring board having a good flatness in which unevenness is prevented from occurring on the surface of the metallized conductor more reliably at least in the exposed portion.

また、メタライズ表面をめっき層で被覆する場合もめっき層のメタライズ表面に対する密着性に優れたメタライズ導体の表面なので、銅粉末間にめっき液等が浸入することをより効果的に防止することができ、メタライズ導体２の腐食をより確実に防止することができる。   Also, when the metallized surface is coated with a plating layer, the surface of the metallized conductor has excellent adhesion to the metallized surface of the plating layer, so that it is possible to more effectively prevent the plating solution from entering the copper powder. Further, corrosion of the metallized conductor 2 can be more reliably prevented.

これによって、配線基板の信頼性をより一層高めることができる。   As a result, the reliability of the wiring board can be further enhanced.

ここで、ガラス質の含有量が６質量％未満では、個々の金属微粒子の体積および熱容量が小さくなるため、金属微粒子の間にガラス成分が入り込む前に金属微粒子、特に銅成分の溶融等が始まり、バインダ等がメタライズ導体２の露出部やその直下等に残留して表面に凹凸を生じるおそれがある。また、絶縁基体１と一体的に焼結させることができず、また銅と絶縁基体１との収縮率の不一致により絶縁基体１に反り等の不具合を発生させてしまう。また、１６質量％を超えると、金属微粒子の間が広くなり過ぎてガラス成分を十分に入り込ませることが難しくなり、空隙が残留してめっき液が入り込むことに起因する腐食等を生じるおそれがある。さらに、金属微粒子が大きくなりすぎて金属微粒子間の焼結性が不十分になり、かえって絶縁基体１に対する接合強度が低くなる傾向がある。   Here, when the glassy content is less than 6% by mass, the volume and heat capacity of the individual metal fine particles become small, so that the metal fine particles, particularly the copper component starts to melt before the glass component enters between the metal fine particles. In addition, the binder or the like may remain on the exposed portion of the metallized conductor 2 or directly below the metalized conductor 2 to cause unevenness on the surface. Further, it cannot be sintered integrally with the insulating substrate 1, and a defect such as warpage is caused in the insulating substrate 1 due to the mismatch of the shrinkage ratio between the copper and the insulating substrate 1. On the other hand, when the amount exceeds 16% by mass, the space between the metal fine particles becomes too wide to make it difficult to allow the glass component to sufficiently enter, and there is a possibility of causing corrosion or the like due to the void remaining and the plating solution entering. . Further, the metal fine particles become too large, the sinterability between the metal fine particles becomes insufficient, and the bonding strength to the insulating substrate 1 tends to be lowered.

また、ガラス質の成分について、ＳｉＯ２が４６．７質量％未満では、結晶化ガラス成分が多くなり、焼結性が悪くなり、めっき液等が内部に侵入しやすくなり、腐食の原因となりやすい。５２．０質量％を超えると非結晶ガラス質が多くなり、焼結しやすくなり、メタライズ表面の凹みやガラス質がメタライズ表面を被覆して、めっき層がうまく被覆しない恐れがある。 In addition, if the SiO 2 content is less than 46.7% by mass for the glassy component, the crystallized glass component increases, the sinterability deteriorates, the plating solution or the like tends to enter the inside, and easily causes corrosion. . If it exceeds 52.0% by mass, the amorphous vitreous substance increases and sintering is likely to occur, and there is a possibility that the metallized surface dents or vitreous coats the metallized surface and the plated layer does not cover well.

また、Ａｌ２Ｏ３が１７．２質量％未満では、非結晶ガラス質が多くなり、焼結しやすくなり、メタライズ表面の凹みやガラ質がメタライズ表面を被覆して、めっき層がうまく被覆しないおそれがある。２３．７質量％を超えると、結晶化ガラス成分が多くなり、焼結性が悪くなり、めっき液等が内部に侵入しやすくなり、腐食の原因となりやすい。 Further, if Al 2 O 3 is less than 17.2% by mass, the amount of amorphous glass is increased and sintering is facilitated, and the metallized surface dents and glass cover the metallized surface and the plating layer does not cover well. There is a fear. If it exceeds 23.7% by mass, the crystallized glass component increases, the sinterability deteriorates, the plating solution or the like tends to enter the inside, and is likely to cause corrosion.

また、Ｂ２Ｏ３が５．８質量％未満では、非結晶ガラス質が多くなり、焼結しやすくなり、メタライズ表面の凹みやガラ質がメタライズ表面を被覆して、めっき層がうまく被覆しないおそれがある。８．３質量％を超えると、結晶化ガラス成分が多くなり、焼結性が悪くなり、めっき液等が内部に侵入しやすくなり、腐食の原因となりやすい。 Further, if B 2 O 3 is less than 5.8% by mass, the amount of amorphous glass is increased and sintering is facilitated, and the metallized surface dents and glassy material cover the metalized surface, and the plating layer does not cover well. There is a fear. If it exceeds 8.3% by mass, the crystallized glass component increases, the sinterability deteriorates, the plating solution or the like tends to enter the inside, and tends to cause corrosion.

また、ＭｇＯが６．０質量％未満では、結晶化ガラス成分が多くなり、焼結性が悪くなり、めっき液等が内部に侵入しやすくなり、腐食の原因となりやすい。９．０質量％を超えると非結晶ガラス質が多くなり、焼結しやすくなり、メタライズ表面の凹みやガラ質がメタライズ表面を被覆して、めっき層がうまく被覆しない恐れがある。   On the other hand, if MgO is less than 6.0% by mass, the crystallized glass component is increased, the sinterability is deteriorated, the plating solution or the like is liable to enter the inside, and is likely to cause corrosion. If the content exceeds 9.0% by mass, the amount of amorphous glass is increased and sintering is likely to occur, and there is a possibility that the metallized surface is covered with dents or glassy material and the plating layer is not coated well.

また、ＢａＯが５．０質量％未満では、結晶化ガラス成分が多くなり、焼結性が悪くなり、めっき液等が内部に侵入しやすくなり、腐食の原因となりやすく、１５．０％質量％を超えると、非結晶ガラス質が多くなり、焼結しやすくなり、メタライズ表面の凹みやガラ質がメタライズ表面を被覆して、めっき層がうまく被覆しないおそれがある。   On the other hand, if the BaO content is less than 5.0% by mass, the crystallized glass component is increased, the sinterability is deteriorated, the plating solution or the like is liable to enter the inside, and is liable to cause corrosion. If it exceeds 1, the amount of amorphous glass will increase, and it will be easy to sinter, and the metallized surface will be covered with dents and glassy material, and the plating layer may not be coated well.

また、ＣａＯが２．７質量％未満では、結晶化ガラス成分が多くなり、焼結性が悪くなり、めっき液等が内部に侵入しやすくなり、腐食の原因となりやすい。８．０％質量％を超えると、非結晶ガラス質が多くなり、焼結しやすくなり、メタライズ表面の凹みやガラ質がメタライズ表面を被覆して、めっき層がうまく被覆しない恐れがある。   On the other hand, when CaO is less than 2.7% by mass, the crystallized glass component is increased, the sinterability is deteriorated, the plating solution or the like is liable to enter the inside, and is likely to cause corrosion. If it exceeds 8.0% by mass, the amount of amorphous glass will increase, and it will be easy to sinter, and there is a possibility that the metallized surface will be covered with dents and glassy material and the plating layer will not be coated well.

また、ＺｎＯが１．２質量％未満では、非結晶ガラス質が多くなり、焼結しやすくなり、メタライズ表面の凹みやガラ質がメタライズ表面を被覆して、めっき層がうまく被覆しない恐れがある。４．７％質量％を超えると、結晶化ガラス成分が多くなり、焼結性が悪くなり、めっき液等が内部に侵入しやすくなり、腐食の原因となりやすい。   If the ZnO content is less than 1.2% by mass, the amount of amorphous glass is increased and sintering is likely to occur, and the metallized surface dents and glassy material may cover the metalized surface and the plating layer may not be coated well. . If it exceeds 4.7% by mass, the crystallized glass component increases, the sinterability deteriorates, the plating solution or the like tends to enter the inside, and is likely to cause corrosion.

また、金属微粒子の粒径は、最小粒径１μｍ以上、最大粒径２０μｍ以下であることが好ましい。かかる構成となすことにより、極端に粒径の小さい金属微粒子や大きいものが混在することは無く、より一層確実に、密に充填することができるとともに、金属微粒子の間に十分にガラス成分を入り込ませることができる。   The metal fine particles preferably have a minimum particle size of 1 μm or more and a maximum particle size of 20 μm or less. By adopting such a configuration, extremely small metal particles and large particles are not mixed together, and can be more reliably and densely packed, and the glass component is sufficiently inserted between the metal particles. Can be made.

すなわち、極端に粒径の小さい金属微粒子が、焼成中に早期に溶融して、バインダの除去やガラス成分の入り込みの妨げになるようなことをより確実に防止することができる。また、極端に粒径の大きな金属粒子の間に大きな空隙が生じてガラス成分を十分に入り込ませることが難しくなるようなことや、金属微粒子間の焼結性が不十分になるようなことをより確実に防止することができる。   That is, it is possible to more reliably prevent the metal fine particles having an extremely small particle diameter from melting at an early stage during firing and hindering the removal of the binder and the entry of the glass component. In addition, a large void is generated between extremely large metal particles, and it is difficult to allow the glass component to sufficiently enter, or that the sinterability between the metal fine particles is insufficient. It can prevent more reliably.

これにより、金属微粒子の間に空隙が残留するのをさらに有効に防止し、金属微粒子間にめっき液等が浸入することに起因したメタライズ導体２の腐食をより確実に防止することができる。 Thereby, it is possible to more effectively prevent the voids from remaining between the metal fine particles, and to more reliably prevent the metallized conductor 2 from being corroded due to the penetration of the plating solution or the like between the metal fine particles.

また、メタライズ導体２は、外部電気回路に接続される部位毎に独立して形成された接続パッド４として形成されており、各接続パッド４から絶縁基体１の内部配線２ａにかけて貫通導体５が形成されていることが好ましい。かかる構成となすことにより、メタライズ導体２の各部位を外部電気回路に、より容易に位置決めして接続することができるとともに、各接続パッド４を、貫通導体５を介して絶縁基体１により接合させることができ、搭載部に搭載された電子部品を接続パッド４を介して、外部電気回路基板に接続できる、より一層の機能性に優れた配線基板９を提供することができる。   The metallized conductor 2 is formed as a connection pad 4 formed independently for each part connected to an external electric circuit, and a through conductor 5 is formed from each connection pad 4 to the internal wiring 2 a of the insulating base 1. It is preferable that With this configuration, each part of the metallized conductor 2 can be more easily positioned and connected to the external electric circuit, and each connection pad 4 is joined to the insulating base 1 via the through conductor 5. In addition, it is possible to provide a wiring board 9 with even higher functionality that can connect an electronic component mounted on the mounting portion to an external electric circuit board via the connection pad 4.

なお、接続パッド４は、例えば、円形状や楕円形状，四角形状等の、個々に独立したパターンで形成される。   Note that the connection pads 4 are formed in an independent pattern such as a circular shape, an elliptical shape, or a rectangular shape.

ここで、内部配線２ａとは、メタライズ導体２を絶縁基体１の内部にも形成した場合、内部に形成された部位を分かり易く区別するための呼び方であり、かかる内部配線２ａは、例えば、絶縁基体１の対向する主面にそれぞれ形成されたメタライズ導体２の間を電気的に接続する機能をなす。内部配線２ａは、絶縁基体１の表面に形成されているメタライズ導体２と同様の金属材料から成り、同様の方法で形成される。   Here, when the metallized conductor 2 is also formed inside the insulating base 1, the internal wiring 2a is a name for distinguishing the portion formed inside easily, and the internal wiring 2a is, for example, It functions to electrically connect the metallized conductors 2 respectively formed on the opposing main surfaces of the insulating substrate 1. The internal wiring 2a is made of the same metal material as the metallized conductor 2 formed on the surface of the insulating base 1, and is formed by the same method.

また、貫通導体５は、例えば、絶縁基体１となるグリーンシートのうち、接続パッド４が形成される部位に一端が位置するような貫通孔を形成しておき、この貫通孔内に、メタライズ導体２を形成するのと同様の金属ペーストを印刷充填しておくことにより形成される。   In addition, the through conductor 5 has, for example, a through hole in which one end is located in a portion of the green sheet to be the insulating base 1 where the connection pad 4 is formed, and the metallized conductor is formed in the through hole. 2 is formed by printing and filling the same metal paste as that for forming 2.

貫通導体５は、接続パッド４と内部配線２ａとを電気的に接続するとともに、それぞれの接続パッド４の絶縁基体１に対する接合を補強する機能をなす。   The through conductor 5 serves to electrically connect the connection pad 4 and the internal wiring 2 a and reinforce the bonding of each connection pad 4 to the insulating substrate 1.

なお、本発明は上述の実施の形態の例に限定されるものではなく、本発明の要旨を逸脱しない範囲であれば種々の変更は可能である。   Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

例えば、メタライズ導体２を被覆するめっき層を、接続パッド４と成る部位とその他の部位とで異なる構成としてもよい。   For example, the plating layer that covers the metallized conductor 2 may be configured to be different between a portion that becomes the connection pad 4 and another portion.

また、絶縁基体１は、平板状のものではなく、上面に電子部品収納用等の凹部を有するものでもよい。   The insulating substrate 1 is not flat and may have a concave portion for storing electronic components on the upper surface.

さらに、凹部を取り囲む絶縁基体１の上面に枠状にメタライズ導体２の露出部を配置し、その枠状の露出部に蓋体をシーム溶接等の手法で接合して凹部を気密封止するようなものでもよい。   Further, an exposed portion of the metallized conductor 2 is disposed in a frame shape on the upper surface of the insulating base 1 surrounding the recess, and a lid is joined to the frame-shaped exposed portion by a technique such as seam welding so that the recess is hermetically sealed. It may be anything.

アルミナ系の組成のガラスセラミック焼結体で外寸が１ｃｍ×１ｃｍの平板状の絶縁基体１を形成し、その表面に銅の金属微粒子によりメタライズ導体２を形成して試験用の配線基板９とした。   A flat insulating substrate 1 having an outer dimension of 1 cm × 1 cm is formed of an alumina-based glass ceramic sintered body, and a metallized conductor 2 is formed of copper fine metal particles on the surface thereof. did.

メタライズ導体２のうち、絶縁基体１の一方の主面に露出するものは、幅０．５ｍｍの線状パターンとし、それと反対側の主面に露出するものは直径０．５ｍｍの円形状のパターンで、縦１０個×横１０個の配列で縦横に並べて形成した。   Of the metallized conductor 2, the one exposed on one main surface of the insulating substrate 1 is a linear pattern having a width of 0.5 mm, and the one exposed on the opposite main surface is a circular pattern having a diameter of 0.5 mm. Then, they were formed by arranging them vertically and horizontally in a 10 × 10 array.

メタライズ導体２の露出表面には、電解めっき法により厚さ２〜５μｍのニッケルめっき層と、厚さ１．５〜２μｍの金めっき層とを順次被着させた。   A nickel plating layer having a thickness of 2 to 5 μm and a gold plating layer having a thickness of 1.5 to 2 μm were sequentially deposited on the exposed surface of the metallized conductor 2 by electrolytic plating.

メタライズ導体２の表面の突起の有無を調べた。   The presence or absence of protrusions on the surface of the metallized conductor 2 was examined.

その後、円形状のパターンを、錫−鉛（共晶）半田を介してプリント配線基板の電気回路に接続し、メタライズ導体２について、表面の凹凸および絶縁基体１に対する接合強度を測定した。   Thereafter, the circular pattern was connected to the electric circuit of the printed wiring board via tin-lead (eutectic) solder, and the surface roughness of the metallized conductor 2 and the bonding strength to the insulating substrate 1 were measured.

上記のメタライズ導体２の強度について、銅粉末の平均粒径を表１に示すように変えて試験し、また最小粒径および最大粒径を表２に示すように変えて試験した。   The strength of the metallized conductor 2 was tested by changing the average particle size of the copper powder as shown in Table 1, and changing the minimum particle size and the maximum particle size as shown in Table 2.

その結果を表１および表２に示す。

Figure 2006237268
The results are shown in Tables 1 and 2.
Figure 2006237268

表１からわかるように、銅の粉末の平均粒径を２乃至９μｍとした本発明の範囲内のものについては、メタライズ導体２の表面には、突起は無く、また、メタライズ導体２と絶縁基体１との間の接合が十分に強固で、接続信頼性が良好であった。   As can be seen from Table 1, for the copper powder having an average particle diameter of 2 to 9 μm within the scope of the present invention, the surface of the metallized conductor 2 has no protrusions, and the metallized conductor 2 and the insulating substrate The connection between the two was sufficiently strong and the connection reliability was good.

これに対し、銅の粉末の平均粒径が２μｍ未満の場合にはメタライズ導体２の表面に突起が見られた。また、９μｍを超える場合にはメタライズ導体２と絶縁基体１との間の接合強度が不十分であった。

Figure 2006237268
On the other hand, when the average particle size of the copper powder was less than 2 μm, protrusions were observed on the surface of the metallized conductor 2. When the thickness exceeds 9 μm, the bonding strength between the metallized conductor 2 and the insulating substrate 1 is insufficient.
Figure 2006237268

また、表２からわかるように、銅の粉末の最小粒径１μｍ未満の場合には、電子部品の実装等に不具合を生じるような異常なものではないものの、若干突出する部位が生じやすくなる傾向が認められた。また、最大粒径２０μｍを超えると、絶縁基体との接合強度が低下する傾向が認められた。   Further, as can be seen from Table 2, when the copper powder has a minimum particle size of less than 1 μm, it is not abnormal to cause a problem in mounting electronic parts, but a slightly protruding part tends to occur. Was recognized. In addition, when the maximum particle size exceeded 20 μm, a tendency that the bonding strength with the insulating substrate was lowered was observed.

本発明の配線基板の実施の形態の一例を示す断面図である。It is sectional drawing which shows an example of embodiment of the wiring board of this invention.

符号の説明Explanation of symbols

１・・・絶縁基体
２・・・メタライズ導体
３・・・めっき層
４・・・接続パッド
５・・・貫通導体
９・・・配線基板 DESCRIPTION OF SYMBOLS 1 ... Insulation base | substrate 2 ... Metallized conductor 3 ... Plating layer 4 ... Connection pad 5 ... Through-conductor 9 ... Wiring board

Claims (6)

ガラスセラミック焼結体から成る絶縁基体と、該絶縁基体の内部に形成されるとともに一部が前記絶縁基体の表面に露出した、銅または銅を主成分とする金属微粒子を含むメタライズ導体とを具備してなり、前記メタライズ導体の露出部が低融点ろう材を介して外部電気回路に電気的に接続される配線基板であって、前記メタライズ導体は、少なくとも前記露出部とその直下部に含まれている金属微粒子が球状を成しているとともに、該金属微粒子の平均粒径が２μｍ乃至９μｍに設定されていることを特徴とする配線基板。 An insulating base made of a glass ceramic sintered body, and a metallized conductor that is formed inside the insulating base and is partially exposed on the surface of the insulating base and containing copper or metal fine particles mainly composed of copper. A wiring board in which the exposed portion of the metallized conductor is electrically connected to an external electric circuit via a low melting point brazing material, and the metallized conductor is included at least in the exposed portion and immediately below the exposed portion. A wiring substrate, wherein the fine metal particles are spherical and the average particle size of the fine metal particles is set to 2 μm to 9 μm. 前記ガラスセラミック焼結体は抗折強度が３３０ＭＰａ以上であることを特徴とする請求項１に記載の配線基板。 The wiring substrate according to claim 1, wherein the glass ceramic sintered body has a bending strength of 330 MPa or more. 前記ガラスセラミック焼結体は縦弾性係数が１６０ＧＰａ以上であることを特徴とする請求項１または請求項２記載の配線基板。 The wiring substrate according to claim 1 or 2, wherein the glass ceramic sintered body has a longitudinal elastic modulus of 160 GPa or more. 前記ガラスセラミック焼結体は熱伝導率が４Ｗ／ｍ・Ｋ以上であることを特徴とする請求項１乃至請求項３のいずれかに記載の配線基板。 The wiring substrate according to any one of claims 1 to 3, wherein the glass ceramic sintered body has a thermal conductivity of 4 W / m · K or more. 前記メタライズ導体は、６〜１６質量％のガラス質を含み、該ガラス質の成分は、ＳｉＯ２が４６．７〜５２．０質量％，Ａｌ２Ｏ３が１７．２〜２３．７質量％，Ｂ２Ｏ３が５．８〜８．３質量％，ＭｇＯが６．０〜９．０質量％，ＢａＯが５．０〜１５．０％，ＣａＯが２．７〜８．０％，ＺｎＯが１．２〜４．７％に設定されていることを特徴とする請求項１乃至請求項４のいずれかに記載の配線基板。 The metallized conductor includes 6 to 16% by mass of vitreous, and the vitreous components include 46.7 to 52.0% by mass of SiO 2 and 17.2 to 23.7% by mass of Al 2 O 3. , B 2 O 3 is 5.8 to 8.3% by mass, MgO is 6.0 to 9.0% by mass, BaO is 5.0 to 15.0%, CaO is 2.7 to 8.0%, The wiring board according to any one of claims 1 to 4, wherein ZnO is set to 1.2 to 4.7%. 前記金属微粒子の粒径が、最小粒径１μｍ以上、最大粒径２０μｍ以下であることを特徴とする請求項１乃至請求項５のいずれかに記載の配線基板。 6. The wiring board according to claim 1, wherein the metal fine particles have a minimum particle size of 1 μm or more and a maximum particle size of 20 μm or less.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5648682B2 (en) * 2010-03-30 2015-01-07 株式会社村田製作所 Metal base substrate

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5648682B2 (en) * 2010-03-30 2015-01-07 株式会社村田製作所 Metal base substrate

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