JP4066631B2

JP4066631B2 - Low temperature fired ceramic material and low temperature fired ceramic substrate

Info

Publication number: JP4066631B2
Application number: JP2001306733A
Authority: JP
Inventors: 和則赤穂
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2001-10-02
Filing date: 2001-10-02
Publication date: 2008-03-26
Anticipated expiration: 2021-10-02
Also published as: JP2003112965A

Description

【０００１】
【発明の属する技術分野】
本発明は、ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃ 系のガラス粉末を含む低温焼成セラミック材料及び低温焼成セラミック基板に関するものである。
【０００２】
【従来の技術】
従来より、セラミック基板として最も多く用いられているアルミナ基板は、誘電率が高く、しかも、１５００℃以上の高温で焼成する必要があるため、同時焼成する配線導体としてＭｏ，Ｗ等の抵抗値の高い高融点金属を使用せざるを得ない。このため、近年の信号処理の高速化・高周波化の要求に対して、アルミナ基板ではパッケージ設計が困難になってきている。
【０００３】
このような事情から、近年、８００〜１０００℃で焼成可能な低温焼成セラミック基板の需要が急速に拡大している。この低温焼成セラミック基板は、同時焼成する配線導体として、Ａｇ、Ａｇ−Ｐｄ、Ａｕ、Ｃｕ等の低抵抗導体の使用が可能で、且つ、セラミックの誘電率が低く、信号処理の高速化・高周波化に対応できるという特長がある。
【０００４】
現在、開発又は実用化されている低温焼成セラミック材料は、結晶化ガラス系や非ガラス系といった単一組成のものもあるが、多くは、ガラスと骨材（結晶質フィラー）との混合物からなるガラス複合系のものである。このガラス複合系の低温焼成セラミック材料としては、例えばＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃ −Ａｌ₂Ｏ₃系のガラス粉末とＡｌ₂Ｏ₃粉末（アルミナ粉末）との混合物がある。
【０００５】
【発明が解決しようとする課題】
ところで、信号処理の高速化・高周波化への適応性を表す指標としてＱｆ値があり、このＱｆ値が高いほど、高速化・高周波化への対応が容易である。上述した従来のガラス複合系の低温焼成セラミック材料は、Ｑｆ値が２０００ＧＨｚ程度であるが、最近の目覚ましく発展する高速化・高周波化に対応するためには、３０００ＧＨｚ以上の高いＱｆ値を持つ低温焼成セラミック材料を新たに開発する必要がある。また、低温焼成セラミック基板とチップとの接続信頼性等を確保するためには、低温焼成セラミック基板の抗折強度等の機械的強度を確保する必要がある。
【０００６】
本発明はこのような事情を考慮してなされたものであり、従ってその目的は、従来より高いＱｆ値と信頼性確保に必要な基板強度を兼ね備えた低温焼成セラミック材料及び低温焼成セラミック基板を提供することにある。
【０００７】
【課題を解決するための手段】
上記目的を達成するために、本発明の請求項１に記載の低温焼成セラミック材料は、Ａｌ₂Ｏ₃（アルミナ）を主成分とする骨材：３５〜４０重量％と、ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラス粉末：６０〜６５重量％とを混合した低温焼成セラミック材料であり、その骨材は、低温焼成セラミック材料総重量に対して、ＢａＯを０．５〜２．０重量％含有し、前記ガラス粉末は、該ガラス粉末総重量に対して、ＳｉＯ ₂ ：４５〜５５重量％、ＣａＯ：１５〜２１重量％、Ｂ ₂ Ｏ ₃ ：６．５〜７．７重量％、Ａｌ ₂ Ｏ ₃ ：４．２〜５．１重量％、ＢａＯ：６．４〜１８重量％、ＺｎＯ：１．５〜２．５重量％、ＳｎＯ ₂ ：２〜４重量％、不純物：２重量％以下を含有することを特徴とするものである。
つまり、骨材とガラス粉末との両方に適量のＢａＯを添加したところに特徴がある。ＢａＯを添加して作製したＢａＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラス粉末は、焼成工程で結晶化すると、Ｑｆ値が高くなる特性がある。更に、骨材にＢａＯを添加すると、焼成工程で、上記のＢａＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラスの結晶が析出しやすくなり、そのガラス析出量が増加する傾向がある。これにより、低温焼成セラミック材料のＱｆ値を３０００ＧＨｚ以上に高めることができる。
【０００８】
この場合、骨材のＢａＯ添加量が０．５重量％よりも少ないと、添加効果が少なく、ガラス析出量が少ない。反対に、骨材のＢａＯ添加量が２．０重量％よりも多いと、後述する試験結果から、抗折強度が低下することが判明している。従って、骨材のＢａＯ添加量の適正範囲は、０．５〜２．０重量％と考えられる。
【０００９】
また、ガラス粉末のＢａＯ添加量が６．４重量％よりも少ないと、ＢａＯの添加効果が少なく、Ｑｆ値の向上幅が少ない。反対に、ガラス粉末のＢａＯ添加量が１８重量％よりも多いと、ガラス化しにくくなる。従って、ガラス粉末のＢａＯ添加量の適正範囲は、６．４〜１８重量％と考えられる。
【００１０】
また、低温焼成セラミック材料中の骨材が３５重量％よりも少ないと（ガラス粉末が６５重量％よりも多いと）、骨材が不足して、抗折強度が弱くなり、反対に、骨材が４０重量％よりも多いと（ガラス粉末が６０重量％よりも少ないと）、ガラスが不足して、焼結不良が発生する可能性がある。従って、骨材を３５〜４０重量％とし、ＢａＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラス粉末を６０〜６５重量％とすれば、実用に耐え得る抗折強度と焼結性とを確保することができる。
【００１１】
また、ガラス原料に、ＢａＯの他に、適量のＺｎＯとＳｎＯ₂を添加して作ったＢａＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃−ＺｎＯ−ＳｎＯ₂系のガラスは、ＺｎＯを添加しないガラスと比較して、Ｑｆ値が高くなると共に、ＺｎＯがガラスの融点を低下させる役割を果たす。また、ガラス粉末を製造する際に、ＳｎＯ₂を添加すると、ＳｎＯ₂を添加し無い場合と比較して、ガラスの融点を３０〜５０℃低下させることができ、ガラス粉末の製造が容易となる。
【００１２】
この場合、ガラス粉末中のＺｎＯが１．５重量％よりも少ないと、ガラスの融点が１４００℃以上となってしまう。反対に、ＺｎＯが２．５重量％よりも多いと、ガラス化しにくくなる。従って、ＺｎＯを１．５〜２．５重量％とすれば、ガラス融点を適度に下げてガラス化を容易にすることができる。
【００１３】
また、ガラス粉末中のＳｎＯ₂が２重量％よりも少ないと、電気的特性が悪くなり、また、ＳｎＯ₂が４重量％よりも多いと、熱膨張が大きくなる。従って、ＳｎＯ₂を２〜４重量％とすれば、電気的特性、熱膨張特性が良くなる。
【００１４】
また、ガラス粉末中のＣａＯが１５重量％よりも少ないと、ｎＳｉＯ₂・ＣａＯ・Ａｌ₂Ｏ₃系の結晶の析出が少なくなり、必要な強度が得られない。反対に、ＣａＯが２１重量％よりも多いと、ガラス融点が低くなり過ぎる。従って、ＣａＯを１５〜２１重量％とすれば、高強度で適度に低いガラス融点とすることができる。
【００１５】
また、ガラス粉末中のＳｉＯ₂が４５重量％よりも少ないと、ｎＳｉＯ₂・ＣａＯ系又はＢａＯ・ＳｉＯ₂系の結晶の析出が少なくなり、必要な強度が得られない。反対に、ＳｉＯ₂が５５重量％よりも多いと、ガラス化しにくくなる。従って、ＳｉＯ₂を４５〜５５重量％とすれば、強度を確保しながら、ガラス化を容易にすることができる。
【００１６】
一般に、ＳｉＯ₂とＣａＯとＢａＯだけでは、融点の高いガラスになるため、融点を低下させる添加剤としてＢ₂Ｏ₃を添加する必要がある。ガラス粉末中のＢ₂Ｏ₃が６．５重量％よりも少ないと、１４００℃以下ではガラス化しにくくなる。反対に、Ｂ₂Ｏ₃が７．７重量％よりも多いと、必要な強度が得られない。従って、Ｂ₂Ｏ₃が６．５〜７．７重量％とすれば、ガラス融点を適度に下げながら、必要な強度を確保することができる。
【００１７】
また、ガラス粉末中のＡｌ₂Ｏ₃は、ガラスの融点を下げる役割を果たすため、Ａｌ₂Ｏ₃が４．２重量％よりも少ないと、ガラスの融点が１４００℃以上となってしまう。反対に、Ａｌ₂Ｏ₃が５．１重量％よりも多いと、ガラス化しにくくなる。従って、Ａｌ₂Ｏ₃が４．２〜５．１重量％とすれば、ガラス融点を適度に下げてガラス化を容易にすることができる。
【００１８】
また、請求項２のように、低温焼成セラミック材料の骨材は、低温焼成セラミック材料総重量に対してＡｌ₂Ｏ₃を３３〜３９．５重量％含有するようにすると良い。つまり、Ａｌ₂Ｏ₃が３３重量％よりも少ないと、抗折強度が弱くなり、反対に、Ａｌ₂Ｏ₃ が３９．５重量％よりも多いと、焼結不良が発生する。従って、Ａｌ₂Ｏ₃を３３〜３９．５重量％とすれば、実用に耐え得る抗折強度と焼結性を確保することができる。
【００１９】
また、請求項３のように、上述した組成の低温焼成セラミック材料を用いて形成したセラミック生基板を８００〜１０００℃で焼成して低温焼成セラミック基板を製造するようにすると良い。これにより、最近の高速化・高周波化に対応できる高いＱｆ値と信頼性確保に必要な基板強度を兼ね備えた高品質の低温焼成セラミック基板を製造することができる。
【００２０】
以上説明した請求項１〜３では、低温焼成セラミック材料の骨材とガラス粉末との両方に適量のＢａＯを添加したが、請求項４のように、低温焼成セラミック材料の骨材のみにＢａＯを添加し、ガラス粉末には、ＢａＯの代わりにＳｒＯを添加しても良い。
【００２１】
請求項４に記載の低温焼成セラミック材料は、Ａｌ₂Ｏ₃（アルミナ）を主成分とする骨材：３５〜４０重量％と、ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラス粉末：６０〜６５重量％とを混合した低温焼成セラミック材料であり、その骨材は、低温焼成セラミック材料総重量に対して、ＢａＯを０．５〜２．０重量％含有し、前記ガラス粉末は、該ガラス粉末総重量に対して、ＳｉＯ ₂ ：４７〜５５重量％、ＣａＯ：１０〜１４．４重量％、Ｂ ₂ Ｏ ₃ ：６．５〜７．２重量％、Ａｌ ₂ Ｏ ₃ ：４．２〜５．０重量％、ＳｒＯ：１１〜１８．８重量％、ＺｎＯ：４．５〜５．５重量％、ＳｎＯ ₂ ：２．０〜４．３重量％、不純物：２重量％以下を含有することを特徴とするものである。このようにＳｒＯを添加して作製したＳｒＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラス粉末は、焼成工程で結晶化すると、抗折強度が高くなる特性がある。更に、骨材にＢａＯを添加すると、焼成工程で、ＢａＯ−ＳｒＯ−ＳｉＯ₂系のガラスの結晶が析出しやすくなり、そのガラス析出量が増加する傾向がある。これにより、低温焼成セラミック材料のＱｆ値を３０００ＧＨｚ以上に高めることができる。
【００２２】
この場合、骨材のＢａＯ添加量が０．５重量％よりも少ないと、添加効果が少なく、ガラス析出量が少ない。反対に、骨材のＢａＯ添加量が２．０重量％よりも多いと、後述する試験結果から、抗折強度が低下することが判明している。従って、骨材のＢａＯ添加量の適正範囲は、０．５〜２．０重量％と考えられる。
【００２３】
また、ガラス粉末のＳｒＯ添加量が１１重量％よりも少ないと、ＳｒＯの添加効果が少なく、抗折強度の向上幅が少ない。反対に、ガラス粉末のＳｒＯ添加量が１８．８重量％よりも多いと、ガラス化しにくくなる。従って、ガラス粉末のＳｒＯ添加量の適正範囲は、１１〜１８．８重量％と考えられる。
【００２４】
また、低温焼成セラミック材料中の骨材が３５重量％よりも少ないと（ガラス粉末が６５重量％よりも多いと）、骨材が不足して、抗折強度が弱くなり、反対に、骨材が４０重量％よりも多いと（ガラス粉末が６０重量％よりも少ないと）、ガラスが不足して、焼結不良が発生する可能性がある。従って、骨材を３５〜４０重量％とし、ＳｒＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラス粉末を６０〜６５重量％とすれば、実用に耐え得る抗折強度と焼結性とを確保することができる。
【００２５】
また、ガラス原料に、ＳｒＯの他に、適量のＺｎＯとＳｎＯ₂を添加して作ったＳｒＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃−ＺｎＯ−ＳｎＯ₂系のガラスは、ＺｎＯを添加しないガラスと比較して、Ｑｆ値が高くなると共に、ＺｎＯがガラスの融点を低下させる役割を果たす。また、ガラス粉末を製造する際に、ＳｎＯ₂を添加すると、ＳｎＯ₂を添加し無い場合と比較して、ガラスの融点を３０〜５０℃低下させることができ、ガラス粉末の製造が容易となる。
【００２６】
この場合、ガラス粉末中のＺｎＯが４．５重量％よりも少ないと、ガラスの融点が１４００℃以上となってしまう。反対に、ＺｎＯが５．５重量％よりも多いと、ガラス化しにくくなる。従って、ＺｎＯを４．５〜５．５重量％とすれば、ガラス融点を適度に下げてガラス化を容易にすることができる。
【００２７】
また、ガラス粉末中のＳｎＯ₂が２重量％よりも少ないと、電気的特性が悪くなり、また、ＳｎＯ₂が４．３重量％よりも多いと、熱膨張が大きくなる。従って、ＳｎＯ₂を２〜４．３重量％とすれば、電気的特性及び熱膨張特性が良くなる。
【００２８】
また、ガラス粉末中のＣａＯが１０重量％よりも少ないと、ｎＳｉＯ₂・ＣａＯ・Ａｌ₂Ｏ₃系の結晶の析出が少なくなり、必要な強度が得られない。反対に、ＣａＯが１４．４重量％よりも多いと、ガラス融点が低くなり過ぎる。従って、ＣａＯを１０〜１４．４重量％とすれば、高強度で適度に低いガラス融点とすることができる。
【００２９】
また、ガラス粉末中のＳｉＯ₂が４７重量％よりも少ないと、ｎＳｉＯ₂・ＣａＯ系又はＳｒＯ・ＳｉＯ₂系の結晶の析出が少なくなり、必要な強度が得られない。反対に、ＳｉＯ₂が５５重量％よりも多いと、ガラス化しにくくなる。従って、ＳｉＯ₂を４７〜５５重量％とすれば、強度を確保しながら、ガラス化を容易にすることができる。
【００３０】
一般に、ＳｉＯ₂とＣａＯとＳｒＯだけでは、融点の高いガラスになるため、融点を低下させる添加剤としてＢ₂Ｏ₃を添加する必要がある。ガラス粉末中のＢ₂Ｏ₃が６．５重量％よりも少ないと、１４００℃以下ではガラス化しにくくなる。反対に、Ｂ₂Ｏ₃が７．２重量％よりも多いと、必要な強度が得られない。従って、Ｂ₂Ｏ₃が６．５〜７．２重量％とすれば、ガラス融点を適度に下げながら、必要な強度を確保することができる。
【００３１】
また、ガラス粉末中のＡｌ₂Ｏ₃は、ガラスの融点を下げる役割を果たすため、Ａｌ₂Ｏ₃が４．２重量％よりも少ないと、ガラスの融点が１４００℃以上となってしまう。反対に、Ａｌ₂Ｏ₃が５．０重量％よりも多いと、ガラス化しにくくなる。従って、Ａｌ₂Ｏ₃が４．２〜５．０重量％とすれば、ガラス融点を適度に下げてガラス化を容易にすることができる。
【００３２】
また、請求項５のように、低温焼成セラミック材料の骨材は、低温焼成セラミック材料総重量に対してＡｌ₂Ｏ₃を３３〜３９．５重量％含有するようにすると良い。つまり、Ａｌ₂Ｏ₃が３３重量％よりも少ないと、抗折強度が弱くなり、反対に、Ａｌ₂Ｏ₃が３９．５重量％よりも多いと、焼結不良が発生する。従って、Ａｌ₂Ｏ₃を３３〜３９．５重量％とすれば、実用に耐え得る抗折強度と焼結性を確保することができる。
【００３３】
また、請求項６のように、上述した組成の低温焼成セラミック材料を用いて形成したセラミック生基板を８００〜１０００℃で焼成して低温焼成セラミック基板を製造するようにすると良い。これにより、最近の高速化・高周波化に対応できる高いＱｆ値と信頼性確保に必要な基板強度を兼ね備えた高品質の低温焼成セラミック基板を製造することができる。
【００３４】
【発明の実施の形態】
［実施形態（１）］
以下、本発明の実施形態（１）を図１に基づいて説明する。低温焼成セラミック多層基板は、低温焼成セラミック材料で形成した複数枚のグリーンシート１１ａ，１１ｂ，１１ｃを積層して８００〜１０００℃で焼成したものである。この場合、低温焼成セラミック材料は、Ａｌ₂Ｏ₃（アルミナ）を主成分とする骨材：３５〜４０重量％とＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラス粉末：６０〜６５重量％とを混合したものを使用する。
【００３５】
低温焼成セラミック材料の骨材は、低温焼成セラミック材料総重量に対して、ＢａＯ：０．５〜２．０重量％とＡｌ₂Ｏ₃：３３〜３９．５重量％を含有している。
【００３６】
ガラス粉末は、該ガラス粉末総重量に対して、ＳｉＯ₂：４５〜５５重量％、ＣａＯ：１５〜２１重量％、Ｂ₂Ｏ₃：６．５〜７．７重量％、Ａｌ₂ Ｏ₃：４．２〜５．１重量％、ＢａＯ：６．４〜１８重量％、ＺｎＯ：１．５〜２．５重量％、ＳｎＯ₂：２〜４重量％、不純物：２重量％以下を含有するＢａＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃−ＺｎＯ−ＳｎＯ₂系のガラス粉末を用いる。
【００３７】
グリーンシート１１ａ，１１ｂ，１１ｃは、上記組成の低温焼成セラミック材料に、バインダー（例えばアクリル系樹脂、ブチラール樹脂）、溶剤（例えばトルエン、キシレン、ブタノール等）及び可塑剤を配合して、十分に撹拌混合してスラリーを作製し、このスラリーを用いてドクターブレード法等でテープ成形したものである。
【００３８】
各層のグリーンシート１１ａ，１１ｂ，１１ｃを積層する前に、各層のグリーンシート１１ａ，１１ｂにパンチング加工されたビアホール１２に、ビア導体１３を充填する。各層のビア導体１３は、例えば、Ａｇ、Ａｇ／Ｐｄ、Ａｇ／Ｐｔ、Ａｇ／Ａｕ等を主に含むＡｇ系導体ペーストの印刷により形成されている。尚、各層のビア導体１３は、Ａｇ系導体ペーストに代えて、Ａｕ系、Ｃｕ系等の低融点金属のペーストを用いても良い。更に、２層目以下のグリーンシート１１ｂ，１１ｃには、ビア導体１３と同種の低融点金属の導体ペーストを使用して内層配線導体１４をスクリーン印刷する。
【００３９】
また、１層目（最上層）のグリーンシート１１ａには、パッドや配線パターン等の表層配線導体１５を上述したＡｇ系、Ａｕ系、Ｃｕ系等の低融点金属の導体ペーストを使用してスクリーン印刷する。尚、表層配線導体１５は、基板焼成後に、後付けで印刷・焼成するようにしても良い。
【００４０】
印刷工程後に、各層のグリーンシート１１ａ，１１ｂ，１１ｃを積層して加熱圧着して一体化して低温焼成セラミック生基板を作製する。そして、この低温焼成セラミック生基板を８００〜１０００℃（好ましくは９００℃以下）で焼成して、各層のグリーンシート１１ａ，１１ｂ，１１ｃとビア導体１３、内層配線導体１４及び表層配線導体１５を同時焼成して、低温焼成セラミック多層基板を製造する。
【００４１】
焼成後の低温焼成セラミック多層基板の組成は、ＳｉＯ₂：２７〜３５．８重量％、ＣａＯ：９〜１３．７重量％、Ｂ₂Ｏ₃：３．９〜５重量％、Ａｌ₂Ｏ₃：３６〜４２．８重量％、ＢａＯ：４．３〜１３．７重量％、ＺｎＯ：０．９〜１．６重量％、ＳｎＯ₂：１．２〜２．６重量％である。
【００４２】
以上説明した本実施形態（１）では、グリーンシート１１ａ，１１ｂ，１１ｃを形成する低温焼成セラミック材料のガラス粉末と骨材の両方に適量のＢａＯを添加したところに特徴があり、更に、ガラス粉末に適量のＺｎＯとＳｎＯ₂を添加したところにも特徴がある。
【００４３】
ＢａＯを添加したガラス粉末は、焼成工程で結晶化すると、Ｑｆ値が高くなる特性がある。更に、骨材に適量のＢａＯを添加すると、焼成工程で、ＢａＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラスの結晶が析出しやくなり、そのガラス析出量が増加する傾向がある。これにより、低温焼成セラミック材料のＱｆ値を３０００ＧＨｚ以上に高めることが可能となる。
【００４４】
また、ガラス原料に、ＢａＯの他に、適量のＺｎＯとＳｎＯ₂を添加して作ったＢａＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃−ＺｎＯ−ＳｎＯ₂ 系のガラスは、ＺｎＯを添加しないガラスと比較して、Ｑｆ値が高くなると共に、ＺｎＯがガラスの融点を低下させる役割を果たす。また、ガラス粉末を製造する際に、ＳｎＯ₂を添加すると、ＳｎＯ₂を添加し無い場合と比較して、ガラスの融点を３０〜５０℃低下させることができ、ガラス粉末の製造が容易となる。
【００４５】
【実施例】
本発明者は、ガラス粉末の組成と、骨材のＢａＯ添加量、ガラス粉末と骨材の配合比の適正範囲を評価する試験を行ったので、その試験結果を次の表１、表２に示す。
【００４６】
【表１】

【００４７】
【表２】

【００４８】
この評価試験では、表１に示す４種類の組成（１）〜（４）のガラス粉末を作製した。このガラス粉末の製造方法は、表１の組成の混合物を溶融してガラス化して急冷し、これを粉砕して平均粒径が１０μｍ程度のガラス粉末を作製した。
【００４９】
この試験に用いた骨材は、ＢａＯを添加しないＡｌ₂Ｏ₃のみの骨材と、低温焼成セラミック材料総重量に対するＢａＯ添加量が０．５重量％、１．０重量％、１．５重量％、２．０重量％、３．０重量％の骨材を使用した。
【００５０】
そして、これらのガラス粉末と骨材とを表２に示す配合比で混合して低温焼成セラミック材料を作製し、この低温焼成セラミック材料に溶剤とアクリル系樹脂（バインダー）と可塑剤を配合して、十分に撹拌混合してスラリーを作製し、このスラリーをドクターブレード法でテープ成形して乾燥させ、厚さ０．１ｍｍのグリーンシートを作製した。
【００５１】
その後、このグリーンシートを１２枚積層して熱圧着した後、これを１０．０ｍｍ×５０．０ｍｍのサイズに切断してサンプル基板を作製した。そして、このサンプル基板を大気中で９００℃、３０分ホールドの条件で焼成し、焼結の良否を評価した。更に、焼結したサンプル基板については、曲げ試験によりサンプル基板の抗折強度を測定した。その結果、表２に示すように、１７種類のサンプル＃１〜＃１７の焼結性と抗折強度の測定値が得られた。
【００５２】
一方、各サンプル＃１〜＃１７のＱｆ値の測定は、次のようにして行った。各サンプル＃１〜＃１７の組成の低温焼成セラミック材料を金型プレスにより直径１５ｍｍの円柱状に成形してサンプルを作製し、このサンプルを大気中で９３０℃、３０分ホールドの条件で焼成した。そして、焼結したサンプルを用いて、誘電体共振法により、Ｑ値と共振周波数ｆを測定し、Ｑｆ値を算出した。このＱｆ値は、信号処理の高速化・高周波化への適応性を表す指標となり、Ｑｆ値が高いほど、高速化・高周波化への対応が容易である。従来のガラス複合系の低温焼成セラミック材料は、Ｑｆ値が２０００ＧＨｚ程度であるが、最近の目覚ましく発展する高速化・高周波化に対応するためには、３０００ＧＨｚ以上の高いＱｆ値を持つことが好ましい。
【００５３】
この評価試験における合格基準は、焼結性が良で、且つ、抗折強度が１７０ＭＰａ以上で、且つ、Ｑｆ値が３０００ＧＨｚ以上であることであり、これら３つの条件が全て満たされた場合に合格（○）と評価し、いずれか１つでも満たさない条件があれば不合格（×）と評価した。
【００５４】
表１の組成（１）のガラス粉末を用いたサンプル＃１、＃２は、いずれも、不合格（×）となった。また、組成（２）〜（４）のガラス粉末を用いたサンプル＃３〜＃１７は、骨材のＢａＯ添加量、ガラス粉末と骨材の配合比によって合格（○）と不合格（×）とに評価が分かれた。
【００５５】
この事から、ガラス粉末の組成については、表１の（２）〜（４）の範囲内が適正であることが判明した。表１の（２）〜（４）のガラス粉末の組成は、該ガラス粉末総重量に対して、ＳｉＯ２：４５〜５５重量％、ＣａＯ：１５〜２１重量％、Ｂ２Ｏ３：６．５〜７．７重量％、Ａｌ２Ｏ３：４．２〜５．１重量％、ＢａＯ：６．４〜１８重量％、ＺｎＯ：１．５〜２．５重量％、ＳｎＯ２：２〜４重量％の範囲内である。
【００５６】
この場合、ガラス粉末のＢａＯ添加量が６．４重量％よりも少ないと、ＢａＯの添加効果が少なく、Ｑｆ値の向上幅が少ない。反対に、ガラス粉末のＢａＯ添加量が１８重量％よりも多いと、ガラス化しにくくなる。従って、ガラス粉末のＢａＯ添加量の適正範囲は、６．４〜１８重量％と考えられる。
【００５７】
また、ガラス粉末中のＺｎＯは、Ｑｆ値を高くすると共に、ガラスの融点を低下させる役割を果たす。ガラス粉末中のＺｎＯが１．５重量％よりも少ないと、ガラスの融点が１４００℃以上となってしまう。反対に、ＺｎＯが２．５重量％よりも多いと、ガラス化しにくくなる。従って、ＺｎＯを１．５〜２．５重量％とすれば、ガラス融点を適度に下げてガラス化を容易にすることができる。
【００５８】
また、ガラス粉末中のＳｎＯ₂が２重量％よりも少ないと、電気的特性が悪くなり、また、ＳｎＯ₂が４重量％よりも多いと、熱膨張が大きくなる。従って、ＳｎＯ₂を２〜４重量％とすれば、電気的特性、熱膨張特性が良くなる。
【００５９】
また、ガラス粉末中のＣａＯが１５重量％よりも少ないと、ｎＳｉＯ₂・ＣａＯ・Ａｌ₂Ｏ₃系の結晶の析出が少なくなり、必要な強度が得られない。反対に、ＣａＯが２１重量％よりも多いと、ガラス融点が低くなり過ぎる。従って、ＣａＯを１５〜２１重量％とすれば、高強度で適度に低いガラス融点とすることができる。
【００６０】
また、ガラス粉末中のＳｉＯ₂が４５重量％よりも少ないと、ｎＳｉＯ₂・ＣａＯ系又はＢａＯ・ＳｉＯ₂系の結晶の析出が少なくなり、必要な強度が得られない。反対に、ＳｉＯ₂が５５重量％よりも多いと、ガラス化しにくくなる。従って、ＳｉＯ₂を４５〜５５重量％とすれば、強度を確保しながら、ガラス化を容易にすることができる。
【００６１】
一般に、ＳｉＯ₂とＣａＯとＢａＯだけでは、融点の高いガラスになるため、融点を低下させる添加剤としてＢ₂Ｏ₃を添加する必要がある。ガラス粉末中のＢ₂Ｏ₃が６．５重量％よりも少ないと、１４００℃以下ではガラス化しにくくなる。反対に、Ｂ₂Ｏ₃が７．７重量％よりも多いと、必要な強度が得られない。従って、Ｂ₂Ｏ₃が６．５〜７．７重量％とすれば、ガラス融点を適度に下げながら、必要な強度を確保することができる。
【００６２】
また、ガラス粉末中のＡｌ₂Ｏ₃は、ガラスの融点を下げる役割を果たすため、Ａｌ₂Ｏ₃が４．２重量％よりも少ないと、ガラスの融点が１４００℃以上となってしまう。反対に、Ａｌ₂Ｏ₃が５．１重量％よりも多いと、ガラス化しにくくなる。従って、Ａｌ₂Ｏ₃が４．２〜５．１重量％とすれば、ガラス融点を適度に下げてガラス化を容易にすることができる。
【００６３】
次に、骨材のＢａＯ添加量の適正範囲を考察する。ＢａＯを添加しないＡｌ₂Ｏ₃のみの骨材を用いたサンプルは、Ｑｆ値が３０００ＧＨｚ未満又は焼結不良となり、不合格（×）と評価された。また、骨材のＢａＯ添加量が０．５重量％、１．０重量％、２．０重量％のサンプルは、いずれも、Ｑｆ値が３０００ＧＨｚ以上、焼結性良好、抗折強度が１７０ＭＰａ以上となり、合格（○）と評価された。しかし、骨材のＢａＯ添加量が３．０重量％のサンプル＃７は、抗折強度が１６５ＭＰａに低下して合格基準（１７０ＭＰａ以上）を満たさず、不合格（×）と評価された。この事から、骨材のＢａＯ添加量の適正範囲は、０．５〜２．０重量％と考えられる。
【００６４】
次に、ガラス粉末と骨材の配合比の適正範囲を考察する。この試験では、ガラス粉末の配合比を５５〜７０重量％、骨材を３０〜４５重量％に設定した。ガラス粉末：５５重量％、骨材：４５重量％のサンプルは、いずれも、ガラスが不足して、焼結不良となり、不合格（×）と評価された。また、ガラス粉末：７０重量％、骨材：３０重量％のサンプルは、いずれも、骨材が不足して、抗折強度が１５０ＭＰａ以下に低下して合格基準（１７０ＭＰａ以上）を満たさず、不合格（×）と評価された。
【００６５】
これに対し、ガラス粉末：６０〜６５重量％、骨材：３５〜４０重量％の場合は、骨材のＢａＯ添加量が適正範囲（０．５〜２．０重量％）のサンプルについては、合格基準（焼結性：良、抗折強度＞１７０ＭＰａ、Ｑｆ値＞３０００ＧＨｚ）の条件を満たし、合格（○）と評価された。この事から、ガラス粉末と骨材の配合比の適正範囲は、ガラス粉末：６０〜６５重量％、骨材：３５〜４０重量％と考えられる。
【００６６】
［実施形態（２）］前記実施形態（１）では、低温焼成セラミック材料の骨材とガラス粉末との両方に適量のＢａＯを添加したが、以下に説明する実施形態（２）では、低温焼成セラミック材料の骨材のみにＢａＯを添加し、ガラス粉末には、ＢａＯの代わりにＳｒＯを添加し、それに伴い、ガラス粉末の各成分の配合比を調整している。
【００６７】
本実施形態（２）においても、グリーンシートを成形する低温焼成セラミック材料は、Ａｌ₂Ｏ₃（アルミナ）を主成分とする骨材：３５〜４０重量％とＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃系のガラス粉末：６０〜６５重量％とを混合したものを使用する。
【００６８】
低温焼成セラミック材料の骨材は、低温焼成セラミック材料総重量に対して、ＢａＯ：０．５〜２．０重量％とＡｌ₂Ｏ₃：３３〜３９．５重量％を含有している。
【００６９】
ガラス粉末は、該ガラス粉末総重量に対して、ＳｉＯ₂：４７〜５５重量％、ＣａＯ：１０〜１４．４重量％、Ｂ₂Ｏ₃：６．５〜７．２重量％、Ａｌ₂Ｏ₃：４．２〜５．０重量％、ＳｒＯ：１１〜１８．８重量％、ＺｎＯ：４．５〜５．５重量％、ＳｎＯ₂：２．０〜４．３重量％、不純物：２重量％以下を含有するＳｒＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃−ＺｎＯ−ＳｎＯ₂系のガラス粉末を用いる。
【００７０】
この組成の低温焼成セラミック材料のスラリーを用いて、前記実施形態（１）と同様の方法でグリーンシートを成形し、導体パターン印刷、グリーンシート積層、焼成工程を順番に実行して、低温焼成セラミック多層基板を製造する。
【００７１】
焼成後の低温焼成セラミック多層基板の組成は、ＳｉＯ₂：２８．２〜３５．８重量％、ＣａＯ：６．０〜９．４重量％、ＢａＯ：０．５〜２．０重量％、Ｂ₂Ｏ₃：３．９〜４．７重量％、Ａｌ₂Ｏ₃：３２．５〜４２．８重量％、ＳｒＯ：６．６〜１２．２重量％、ＺｎＯ：２．７〜３．６重量％、ＳｎＯ₂ ：１．２〜２．８重量％である。
【００７２】
以上説明した本実施形態（２）では、グリーンシートを形成する低温焼成セラミック材料の骨材のみにＢａＯを添加し、ガラス粉末には、ＢａＯの代わりにＳｒＯを添加したところに特徴があり、更にガラス粉末に適量のＺｎＯとＳｎＯ₂を添加したところにも特徴がある。
【００７３】
ＳｒＯを添加したガラス粉末は、焼成工程で結晶化すると、抗折強度が高くなる特性がある。更に、骨材に適量のＢａＯを添加すると、焼成工程で、ＢａＯ−ＳｒＯ−ＳｉＯ₂系のガラスの結晶が析出しやくなり、そのガラス析出量が増加する傾向がある。これにより、低温焼成セラミック材料のＱｆ値を３０００ＧＨｚ以上に高めることが可能となる。
【００７４】
また、ガラス原料に、ＳｒＯの他に、適量のＺｎＯとＳｎＯ₂を添加して作ったＳｒＯ−ＳｉＯ₂−ＣａＯ−Ｂ₂Ｏ₃−Ａｌ₂Ｏ₃−ＺｎＯ−ＳｎＯ₂ 系のガラスは、ＺｎＯを添加しないガラスと比較して、Ｑｆ値が高くなると共に、ＺｎＯがガラスの融点を低下させる役割を果たす。また、ガラス粉末を製造する際に、ＳｎＯ₂を添加すると、ＳｎＯ₂を添加し無い場合と比較して、ガラスの融点を３０〜５０℃低下させることができ、ガラス粉末の製造が容易となる。
【００７５】

【実施例】
本実施形態（２）の組成の低温焼成セラミック材料に関しても、本発明者は、ガラス粉末の組成と、骨材のＢａＯ添加量、ガラス粉末と骨材の配合比の適正範囲を評価する試験を行ったので、その試験結果を次の表３、表４に示す。
【００７６】
【表３】

【００７７】
【表４】

【００７８】
この評価試験では、表３に示す４種類の組成（１）〜（４）のガラス粉末を作製した。このガラス粉末の製造方法は、表３の組成の混合物を溶融してガラス化して急冷し、これを粉砕して平均粒径が１０μｍ程度のガラス粉末を作製した。
【００７９】
この試験に用いた骨材は、ＢａＯを添加しないＡｌ₂Ｏ₃のみの骨材と、低温焼成セラミック材料総重量に対するＢａＯ添加量が０．５重量％、１．０重量％、１．５重量％、２．０重量％、３．０重量％の骨材を使用した。
【００８０】
そして、これらのガラス粉末と骨材とを表４に示す配合比で混合して低温焼成セラミック材料を作製し、この低温焼成セラミック材料に溶剤とアクリル系樹脂（バインダー）と可塑剤を配合して、十分に撹拌混合してスラリーを作製し、このスラリーをドクターブレード法でテープ成形して乾燥させ、厚さ０．１ｍｍのグリーンシートを作製した。
【００８１】
その後、このグリーンシートを１２枚積層して熱圧着した後、これを１０．０ｍｍ×５０．０ｍｍのサイズに切断してサンプル基板を作製した。そして、このサンプル基板を大気中で９００℃、３０分ホールドの条件で焼成し、焼結の良否を評価した。更に、焼結したサンプル基板については、曲げ試験によりサンプル基板の抗折強度を測定した。その結果、表４に示すように、１７種類のサンプル＃２１〜＃３７の焼結性と抗折強度の測定値が得られた。尚、各サンプル＃２１〜＃３７のＱｆ値の測定方法は前記実施形態（１）と同じである。
【００８２】
この評価試験における合格基準は、焼結性が良で、且つ、抗折強度が２００ＭＰａ以上で、且つ、Ｑｆ値が３０００ＧＨｚ以上であることであり、これら３つの条件が全て満たされた場合に合格（○）と評価し、いずれか１つでも満たさない条件があれば不合格（×）と評価した。
【００８３】
表３の組成（１）のガラス粉末を用いたサンプル＃２１、＃２２は、いずれも、不合格（×）となった。また、組成（２）〜（４）のガラス粉末を用いたサンプル＃２３〜＃３７は、骨材のＢａＯ添加量、ガラス粉末と骨材の配合比によって合格（○）と不合格（×）とに評価が分かれた。
【００８４】
この事から、ガラス粉末の組成については、表３の（２）〜（４）の範囲内が適正であることが判明した。表３の（２）〜（４）のガラス粉末の組成は、ガラス粉末総重量に対して、ＳｉＯ₂：４７〜５５重量％、ＣａＯ：１０〜１４．４重量％、Ｂ₂Ｏ₃：６．５〜７．２重量％、Ａｌ₂Ｏ₃：４．２〜５．０重量％、ＳｒＯ：１１〜１８．８重量％、ＺｎＯ：４．５〜５．５重量％、ＳｎＯ₂：２〜４．３重量％の範囲内である。
【００８５】
この場合、ガラス粉末のＳｒＯ添加量が１１重量％よりも少ないと、ＳｒＯの添加効果が少なく、抗折強度の向上幅が少ない。反対に、ガラス粉末のＳｒＯ添加量が１８．８重量％よりも多いと、ガラス化しにくくなる。従って、ガラス粉末のＳｒＯ添加量の適正範囲は、１１〜１８．８重量％と考えられる。
【００８６】
また、ガラス粉末中のＺｎＯは、Ｑｆ値を高くすると共に、ガラスの融点を低下させる役割を果たす。ガラス粉末中のＺｎＯが４．５重量％よりも少ないと、ガラスの融点が１４００℃以上となってしまう。反対に、ＺｎＯが５．５重量％よりも多いと、ガラス化しにくくなる。従って、ＺｎＯを４．５〜５．５重量％とすれば、ガラス融点を適度に下げてガラス化を容易にすることができる。
【００８７】
また、ガラス粉末中のＳｎＯ₂が２重量％よりも少ないと、電気的特性が悪くなり、また、ＳｎＯ₂が４．３重量％よりも多いと、熱膨張が大きくなる。従って、ＳｎＯ₂を２〜４．３重量％とすれば、電気的特性及び熱膨張特性が良くなる。
【００８８】
また、ガラス粉末中のＣａＯが１０重量％よりも少ないと、ｎＳｉＯ₂・ＣａＯ・Ａｌ₂Ｏ₃系の結晶の析出が少なくなり、必要な強度が得られない。反対に、ＣａＯが１４．４重量％よりも多いと、ガラス融点が低くなり過ぎる。従って、ＣａＯを１０〜１４．４重量％とすれば、高強度で適度に低いガラス融点とすることができる。
【００８９】
また、ガラス粉末中のＳｉＯ₂が４７重量％よりも少ないと、ｎＳｉＯ₂・ＣａＯ系又はＳｒＯ・ＳｉＯ₂系の結晶の析出が少なくなり、必要な強度が得られない。反対に、ＳｉＯ₂が５５重量％よりも多いと、ガラス化しにくくなる。従って、ＳｉＯ₂を４７〜５５重量％とすれば、強度を確保しながら、ガラス化を容易にすることができる。
【００９０】
一般に、ＳｉＯ₂とＣａＯとＳｒＯだけでは、融点の高いガラスになるため、融点を低下させる添加剤としてＢ₂Ｏ₃を添加する必要がある。ガラス粉末中のＢ₂Ｏ₃が６．５重量％よりも少ないと、１４００℃以下ではガラス化しにくくなる。反対に、Ｂ₂Ｏ₃が７．２重量％よりも多いと、必要な強度が得られない。従って、Ｂ₂Ｏ₃が６．５〜７．２重量％とすれば、ガラス融点を適度に下げながら、必要な強度を確保することができる。
【００９１】
また、ガラス粉末中のＡｌ₂Ｏ₃は、ガラスの融点を下げる役割を果たすため、Ａｌ₂Ｏ₃が４．２重量％よりも少ないと、ガラスの融点が１４００℃以上となってしまう。反対に、Ａｌ₂Ｏ₃が５．０重量％よりも多いと、ガラス化しにくくなる。従って、Ａｌ₂Ｏ₃が４．２〜５．０重量％とすれば、ガラス融点を適度に下げてガラス化を容易にすることができる。
【００９２】
次に、骨材のＢａＯ添加量の適正範囲を考察する。ＢａＯを添加しないＡｌ₂Ｏ₃のみの骨材を用いたサンプルは、Ｑｆ値が３０００ＧＨｚ未満又は焼結不良となり、不合格（×）と評価された。また、骨材のＢａＯ添加量が０．５重量％、１．０重量％、２．０重量％のサンプルは、いずれも、Ｑｆ値が３０００ＧＨｚ以上、焼結性良好、抗折強度が２００ＭＰａ以上となり、合格（○）と評価された。しかし、骨材のＢａＯ添加量が３．０重量％のサンプル＃２７は、抗折強度が１７０ＭＰａに低下して合格基準（２００ＭＰａ以上）を満たさず、不合格（×）と評価された。この事から、骨材のＢａＯ添加量の適正範囲は、０．５〜２．０重量％と考えられる。
【００９３】
次に、ガラス粉末と骨材の配合比の適正範囲を考察する。この試験では、ガラス粉末の配合比を５５〜７０重量％、骨材を３０〜４５重量％に設定した。ガラス粉末：５５重量％、骨材：４５重量％のサンプルは、いずれも、ガラスが不足して、焼結不良となり、不合格（×）と評価された。また、ガラス粉末：７０重量％、骨材：３０重量％のサンプルは、いずれも、骨材が不足して、抗折強度が１５０ＭＰａ以下に低下して合格基準（２００ＭＰａ以上）を満たさず、不合格（×）と評価された。
【００９４】
これに対し、ガラス粉末：６０〜６５重量％、骨材：３５〜４０重量％の場合は、骨材のＢａＯ添加量が適正範囲（０．５〜２．０重量％）のサンプルについては、合格基準（焼結性：良、抗折強度＞２００ＭＰａ、Ｑｆ値＞３０００ＧＨｚ）の条件を満たし、合格（○）と評価された。この事から、ガラス粉末と骨材の配合比の適正範囲は、ガラス粉末：６０〜６５重量％、骨材：３５〜４０重量％と考えられる。
【００９５】
【発明の効果】
以上の説明から明らかなように、本発明の請求項１の低温焼成セラミック材料は、骨材とガラス粉末との両方に適量のＢａＯを添加したので、低温焼成セラミック材料のＱｆ値を３０００ＧＨｚ以上に高めることができて、最近の目覚ましく発展する高速化・高周波化に対応することができると共に、基板の信頼性確保に必要な機械的な強度を持たせることができる。
【００９６】
更に、ガラス原料に、ＢａＯの他に、適量のＺｎＯとＳｎＯ₂を添加したので、Ｑｆ値を更に高くできると共に、ガラスの融点を低下させることができ、ガラス粉末の製造が容易となる。
【００９７】
また、請求項２では、骨材のＡｌ₂Ｏ₃含有量を、低温焼成セラミック材料総重量に対して３３〜３９．５重量％としたので、実用に耐え得る抗折強度と焼結性を確保することができる。
【００９８】
また、請求項３では、上述した組成の低温焼成セラミック材料を用いて形成したセラミック生基板を８００〜１０００℃で焼成して低温焼成セラミック基板を製造するようにしたので、最近の高速化・高周波化に対応できる高いＱｆ値と信頼性確保に必要な基板強度を兼ね備えた高品質の低温焼成セラミック基板を製造することができる。
【００９９】
また、請求項４では、低温焼成セラミック材料の骨材のみにＢａＯを添加し、ガラス粉末には、ＢａＯの代わりにＳｒＯを添加したので基板の機械的な強度を更に向上できると共に、低温焼成セラミック材料のＱｆ値を３０００ＧＨｚ以上に高めることができて、最近の目覚ましく発展する高速化・高周波化に対応することができる。
【０１００】
更に、ガラス原料に、適量のＺｎＯとＳｎＯ₂を添加したので、Ｑｆ値を更に高くできると共に、ガラスの融点を低下させることができ、ガラス粉末の製造が容易となる。
【０１０１】
また、請求項５では、骨材のＡｌ₂Ｏ₃含有量を、低温焼成セラミック材料総重量に対して３３〜３９．５重量％としたので、実用に耐え得る抗折強度と焼結性を確保することができる。
【０１０２】
また、請求項６では、上述した組成の低温焼成セラミック材料を用いて形成したセラミック生基板を８００〜１０００℃で焼成して低温焼成セラミック基板を製造するようにしたので、最近の高速化・高周波化に対応できる高いＱｆ値と信頼性確保に必要な基板強度を兼ね備えた高品質の低温焼成セラミック基板を製造することができる。
【図面の簡単な説明】
【図１】本発明の実施形態（１）を示す低温焼成セラミック多層基板の縦断面図
【符号の説明】
１１ａ，１１ｂ，１１ｃ．．．低温焼成セラミックのグリーンシート、１２．．．ビアホール、１３．．．ビア導体、１４．．．内層配線導体、１５．．．表層配線導体。[0001]
BACKGROUND OF THE INVENTION
The present invention provides SiO₂-CaO-B₂O_Three-Al₂O_Three  The present invention relates to a low-temperature fired ceramic material and a low-temperature fired ceramic substrate containing a glass powder of the system.
[0002]
[Prior art]
Conventionally, the alumina substrate most frequently used as a ceramic substrate has a high dielectric constant and needs to be fired at a high temperature of 1500 ° C. or higher. A high refractory metal must be used. For this reason, package design has become difficult with alumina substrates in response to recent demands for higher speed and higher frequency of signal processing.
[0003]
Under such circumstances, in recent years, the demand for a low-temperature fired ceramic substrate that can be fired at 800 to 1000 ° C. is rapidly expanding. This low-temperature fired ceramic substrate can use a low-resistance conductor such as Ag, Ag-Pd, Au, Cu, etc. as a wiring conductor to be fired at the same time, and the dielectric constant of the ceramic is low. It has the feature that it can respond to conversion.
[0004]
Currently, low-temperature fired ceramic materials that have been developed or put into practical use include single crystal compositions such as crystallized glass and non-glass, but many are composed of a mixture of glass and aggregate (crystalline filler). Glass composite system. As this glass composite low-temperature fired ceramic material, for example, SiO₂-CaO-B₂O_Three  -Al₂O_ThreeGlass powder and Al₂O_ThreeThere is a mixture with powder (alumina powder).
[0005]
[Problems to be solved by the invention]
By the way, there is a Qf value as an index indicating the adaptability to high speed and high frequency of signal processing. The higher this Qf value, the easier the response to high speed and high frequency. The above-mentioned conventional glass composite low-temperature fired ceramic material has a Qf value of about 2000 GHz. However, in order to cope with the recent rapid development of high speed and high frequency, low-temperature fired having a high Qf value of 3000 GHz or more. There is a need to develop new ceramic materials. Further, in order to ensure the connection reliability between the low-temperature fired ceramic substrate and the chip, it is necessary to ensure the mechanical strength such as the bending strength of the low-temperature fired ceramic substrate.
[0006]
The present invention has been made in view of such circumstances. Accordingly, the object of the present invention is to provide a low-temperature fired ceramic material and a low-temperature fired ceramic substrate having both a higher Qf value and a substrate strength necessary for ensuring reliability. There is to do.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the low-temperature fired ceramic material according to claim 1 of the present invention is made of Al.₂O_Three(Alumina) -based aggregate: 35-40% by weight, SiO₂-CaO-B₂O_Three-Al₂O_ThreeGlass powder of the system: a low-temperature fired ceramic material mixed with 60 to 65% by weight, and the aggregate contains 0.5 to 2.0% by weight of BaO with respect to the total weight of the low-temperature fired ceramic material, The glass powder is based on the total weight of the glass powder.SiO ₂ : 45-55 wt%, CaO: 15-21 wt%, B ₂ O _Three : 6.5 to 7.7% by weight, Al ₂ O _Three : 4.2-5.1 wt%, BaO: 6.4-18 wt%, ZnO: 1.5-2.5 wt%, SnO ₂ : 2 to 4% by weight, impurities: 2% by weight or lessIt is characterized by this.
  That is, it is characterized in that an appropriate amount of BaO is added to both the aggregate and the glass powder. BaO-SiO prepared by adding BaO₂-CaO-B₂O_Three-Al₂O_ThreeThe glass powder of the system has a characteristic that the Qf value becomes high when crystallized in the firing step. Furthermore, when BaO is added to the aggregate, the BaO—SiO is used in the firing step.₂-CaO-B₂O_Three-Al₂O_ThreeThere is a tendency that the crystal of the glass of the system tends to precipitate and the amount of the deposited glass increases. Thereby, the Qf value of the low-temperature fired ceramic material can be increased to 3000 GHz or more.
[0008]
In this case, if the amount of BaO added to the aggregate is less than 0.5% by weight, the effect of addition is small and the amount of glass deposited is small. On the contrary, when the BaO addition amount of the aggregate is more than 2.0% by weight, it has been found from the test results described later that the bending strength is lowered. Therefore, the appropriate range of the BaO addition amount of the aggregate is considered to be 0.5 to 2.0% by weight.
[0009]
Further, when the BaO addition amount of the glass powder is less than 6.4% by weight, the effect of adding BaO is small and the Qf value is not improved. On the contrary, when the BaO addition amount of the glass powder is more than 18% by weight, vitrification becomes difficult. Therefore, the appropriate range of the BaO addition amount of the glass powder is considered to be 6.4 to 18% by weight.
[0010]
Also, if the aggregate in the low-temperature fired ceramic material is less than 35% by weight (if the glass powder is more than 65% by weight), the aggregate is insufficient and the bending strength is weakened. If it is more than 40% by weight (if the glass powder is less than 60% by weight), the glass may be insufficient and sintering failure may occur. Therefore, the aggregate is 35 to 40% by weight, BaO-SiO.₂-CaO-B₂O_Three-Al₂O_ThreeIf the glass powder of the system is 60 to 65% by weight, the bending strength and the sinterability that can withstand practical use can be ensured.
[0011]
Also,In addition to BaO, suitable amounts of ZnO and SnO₂Made by adding BaO-SiO₂-CaO-B₂O_Three-Al₂O_Three-ZnO-SnO₂The system glass has a Qf value higher than that of glass not added with ZnO, and ZnO plays a role of lowering the melting point of the glass. In addition, when producing glass powder, SnO₂When SnO is added₂Compared with the case where no is added, the melting point of the glass can be lowered by 30 to 50 ° C., and the production of the glass powder becomes easy.
[0012]
In this case, if ZnO in the glass powder is less than 1.5% by weight, the melting point of the glass becomes 1400 ° C. or higher. On the other hand, when ZnO is more than 2.5% by weight, vitrification becomes difficult. Therefore, if ZnO is 1.5 to 2.5% by weight, the glass melting point can be lowered appropriately to facilitate vitrification.
[0013]
In addition, SnO in glass powder₂Is less than 2% by weight, the electrical properties deteriorate, and SnO₂When the amount is more than 4% by weight, the thermal expansion increases. Therefore, SnO₂When the content is 2 to 4% by weight, electrical characteristics and thermal expansion characteristics are improved.
[0014]
If the CaO content in the glass powder is less than 15% by weight, nSiO₂・ CaO ・ Al₂O_ThreePrecipitation of crystals in the system is reduced and the required strength cannot be obtained. On the contrary, if the CaO content is more than 21% by weight, the glass melting point becomes too low. Accordingly, if CaO is 15 to 21% by weight, the glass melting point can be made high and moderately low.
[0015]
In addition, SiO in glass powder₂Is less than 45% by weight, nSiO₂・ CaO or BaO ・ SiO₂Precipitation of crystals in the system is reduced and the required strength cannot be obtained. Conversely, SiO₂When it is more than 55% by weight, vitrification becomes difficult. Therefore, SiO₂If it is 45 to 55 weight%, vitrification can be made easy, ensuring intensity | strength.
[0016]
In general, SiO₂And CaO and BaO alone result in a glass with a high melting point, so B as an additive to lower the melting point₂O_ThreeNeed to be added. B in glass powder₂O_ThreeIs less than 6.5% by weight, it becomes difficult to vitrify at 1400 ° C. or lower. Conversely, B₂O_ThreeIs more than 7.7% by weight, the required strength cannot be obtained. Therefore, B₂O_ThreeIs 6.5 to 7.7% by weight, the required strength can be ensured while the glass melting point is appropriately lowered.
[0017]
In addition, Al in glass powder₂O_ThreePlays a role in lowering the melting point of glass, so Al₂O_ThreeIf it is less than 4.2% by weight, the melting point of the glass becomes 1400 ° C. or higher. Conversely, Al₂O_ThreeIs more than 5.1% by weight, it becomes difficult to vitrify. Therefore, Al₂O_ThreeIf it is 4.2 to 5.1 weight%, glass melting point can be lowered | hung moderately and vitrification can be made easy.
[0018]
Claims2Thus, the aggregate of the low-temperature fired ceramic material is Al to the total weight of the low-temperature fired ceramic material.₂O_ThreeIt is good to contain 33-39.5 weight%. That is, Al₂O_ThreeIf it is less than 33% by weight, the bending strength is weakened.₂O_Three  If it is more than 39.5% by weight, sintering failure occurs. Therefore, Al₂O_ThreeIf it is 33-39.5 weight%, the bending strength and sinterability which can be practically used can be ensured.
[0019]
Claims3As described above, a ceramic raw substrate formed using the low-temperature fired ceramic material having the above-described composition may be fired at 800 to 1000 ° C. to produce a low-temperature fired ceramic substrate. As a result, it is possible to manufacture a high-quality low-temperature fired ceramic substrate having both a high Qf value that can cope with the recent increase in speed and frequency and the substrate strength necessary for ensuring reliability.
[0020]
Claims 1 to 1 explained above3Then, an appropriate amount of BaO was added to both the aggregate of the low-temperature fired ceramic material and the glass powder.4As described above, BaO may be added only to the aggregate of the low-temperature fired ceramic material, and SrO may be added to the glass powder instead of BaO.
[0021]
Claim4The low-temperature fired ceramic material described in Al₂O_Three(Alumina) -based aggregate: 35-40% by weight, SiO₂-CaO-B₂O_Three-Al₂O_ThreeGlass powder of the system: a low-temperature fired ceramic material mixed with 60 to 65% by weight, and the aggregate contains 0.5 to 2.0% by weight of BaO with respect to the total weight of the low-temperature fired ceramic material, The glass powder is based on the total weight of the glass powder.SiO ₂ : 47 to 55 wt%, CaO: 10 to 14.4 wt%, B ₂ O _Three : 6.5 to 7.2% by weight, Al ₂ O _Three : 4.2 to 5.0% by weight, SrO: 11 to 18.8% by weight, ZnO: 4.5 to 5.5% by weight, SnO ₂ : 2.0 to 4.3 wt%, impurities: 2 wt% or lessIt is characterized by containing. SrO—SiO prepared by adding SrO in this way₂-CaO-B₂O_Three-Al₂O_ThreeWhen the glass powder of the system is crystallized in the firing process, it has a characteristic that the bending strength is increased. Furthermore, when BaO is added to the aggregate, BaO—SrO—SiO is used in the firing step.₂There is a tendency that the crystal of the glass of the system tends to precipitate and the amount of the deposited glass increases. Thereby, the Qf value of the low-temperature fired ceramic material can be increased to 3000 GHz or more.
[0022]
In this case, if the amount of BaO added to the aggregate is less than 0.5% by weight, the effect of addition is small and the amount of glass deposited is small. On the contrary, when the BaO addition amount of the aggregate is more than 2.0% by weight, it has been found from the test results described later that the bending strength is lowered. Therefore, the appropriate range of the BaO addition amount of the aggregate is considered to be 0.5 to 2.0% by weight.
[0023]
On the other hand, when the SrO addition amount of the glass powder is less than 11% by weight, the effect of adding SrO is small, and the width of improvement in bending strength is small. On the contrary, when the SrO addition amount of the glass powder is more than 18.8% by weight, vitrification becomes difficult. Therefore, the appropriate range of the SrO addition amount of the glass powder is considered to be 11 to 18.8% by weight.
[0024]
Also, if the aggregate in the low-temperature fired ceramic material is less than 35% by weight (if the glass powder is more than 65% by weight), the aggregate is insufficient and the bending strength is weakened. If it is more than 40% by weight (if the glass powder is less than 60% by weight), the glass may be insufficient and sintering failure may occur. Therefore, the aggregate is 35 to 40% by weight, and SrO—SiO.₂-CaO-B₂O_Three-Al₂O_ThreeIf the glass powder of the system is 60 to 65% by weight, the bending strength and the sinterability that can withstand practical use can be ensured.
[0025]
  Also,In addition to SrO, suitable amounts of ZnO and SnO for glass raw materials₂Made by adding SrO-SiO₂-CaO-B₂O_Three-Al₂O_Three-ZnO-SnO₂The system glass has a Qf value higher than that of glass not added with ZnO, and ZnO plays a role of lowering the melting point of the glass. In addition, when producing glass powder, SnO₂When SnO is added₂Compared with the case where no is added, the melting point of the glass can be lowered by 30 to 50 ° C., and the production of the glass powder becomes easy.
[0026]
In this case, if ZnO in the glass powder is less than 4.5% by weight, the melting point of the glass becomes 1400 ° C. or higher. On the other hand, when ZnO is more than 5.5% by weight, vitrification becomes difficult. Therefore, if ZnO is 4.5 to 5.5% by weight, the glass melting point can be lowered appropriately to facilitate vitrification.
[0027]
In addition, SnO in glass powder₂Is less than 2% by weight, the electrical properties deteriorate, and SnO₂When the amount is more than 4.3% by weight, the thermal expansion increases. Therefore, SnO₂When the content is 2 to 4.3% by weight, the electrical characteristics and the thermal expansion characteristics are improved.
[0028]
Further, when CaO in the glass powder is less than 10% by weight, nSiO₂・ CaO ・ Al₂O_ThreePrecipitation of crystals in the system is reduced and the required strength cannot be obtained. On the contrary, when CaO is more than 14.4% by weight, the glass melting point becomes too low. Accordingly, if CaO is 10 to 14.4% by weight, the glass melting point can be made high and moderately low.
[0029]
In addition, SiO in glass powder₂Is less than 47% by weight, nSiO₂・ CaO or SrO ・ SiO₂Precipitation of crystals in the system is reduced and the required strength cannot be obtained. Conversely, SiO₂When it is more than 55% by weight, vitrification becomes difficult. Therefore, SiO₂If it is 47 to 55 weight%, vitrification can be made easy, ensuring intensity | strength.
[0030]
In general, SiO₂And CaO and SrO alone result in a glass with a high melting point, so B as an additive to lower the melting point₂O_ThreeNeed to be added. B in glass powder₂O_ThreeIs less than 6.5% by weight, it becomes difficult to vitrify at 1400 ° C. or lower. Conversely, B₂O_ThreeIs more than 7.2% by weight, the required strength cannot be obtained. Therefore, B₂O_ThreeIs 6.5 to 7.2% by weight, the required strength can be ensured while the glass melting point is appropriately lowered.
[0031]
In addition, Al in glass powder₂O_ThreePlays a role in lowering the melting point of glass, so Al₂O_ThreeIf it is less than 4.2% by weight, the melting point of the glass becomes 1400 ° C. or higher. Conversely, Al₂O_ThreeWhen it is more than 5.0% by weight, vitrification becomes difficult. Therefore, Al₂O_ThreeIf it is 4.2 to 5.0 weight%, glass melting point can be lowered | hung moderately and vitrification can be made easy.
[0032]
Claims5Thus, the aggregate of the low-temperature fired ceramic material is Al to the total weight of the low-temperature fired ceramic material.₂O_ThreeIt is good to contain 33-39.5 weight%. That is, Al₂O_ThreeIf it is less than 33% by weight, the bending strength is weakened.₂O_ThreeIf it is more than 39.5% by weight, sintering failure occurs. Therefore, Al₂O_ThreeIf it is 33-39.5 weight%, the bending strength and sinterability which can be practically used can be ensured.
[0033]
Claims6As described above, a ceramic raw substrate formed using the low-temperature fired ceramic material having the above-described composition may be fired at 800 to 1000 ° C. to produce a low-temperature fired ceramic substrate. As a result, it is possible to manufacture a high-quality low-temperature fired ceramic substrate having both a high Qf value that can cope with the recent increase in speed and frequency and the substrate strength necessary for ensuring reliability.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment (1)]
  Hereinafter, embodiment (1) of this invention is described based on FIG. The low-temperature fired ceramic multilayer substrate is obtained by laminating a plurality of

green sheets

11a, 11b, and 11c formed of a low-temperature fired ceramic material and firing them at 800 to 1000 ° C. In this case, the low-temperature fired ceramic material is Al₂O_Three(Alumina) -based aggregate: 35-40% by weight and SiO₂-CaO-B₂O_Three-Al₂O_ThreeGlass powder of the system: a mixture of 60 to 65% by weight is used.
[0035]
The aggregate of the low-temperature fired ceramic material is BaO: 0.5 to 2.0% by weight with respect to the total weight of the low-temperature fired ceramic material.₂O_Three: 33 to 39.5% by weight.
[0036]
The glass powder is composed of SiO2 with respect to the total weight of the glass powder.₂: 45-55 wt%, CaO: 15-21 wt%, B₂O_Three: 6.5 to 7.7% by weight, Al₂ O_Three: 4.2-5.1 wt%, BaO: 6.4-18 wt%, ZnO: 1.5-2.5 wt%, SnO₂: BaO-SiO containing 2 to 4% by weight, impurities: 2% by weight or less₂-CaO-B₂O_Three-Al₂O_Three-ZnO-SnO₂Glass powder of the system is used.
[0037]
The

green sheets

11a, 11b, and 11c are mixed with a binder (for example, acrylic resin, butyral resin), a solvent (for example, toluene, xylene, butanol, etc.) and a plasticizer in the low-temperature fired ceramic material having the above composition, and sufficiently stirred. A slurry is prepared by mixing, and this slurry is tape-molded by the doctor blade method or the like.
[0038]
Before the

green sheets

11a, 11b, and 11c of each layer are stacked, the via conductors 13 are filled into the via holes 12 punched in the

green sheets

11a and 11b of the respective layers. The via conductors 13 in each layer are formed by printing an Ag-based conductor paste mainly containing Ag, Ag / Pd, Ag / Pt, Ag / Au, or the like, for example. The via conductors 13 in each layer may be made of a paste of low melting point metal such as Au or Cu instead of the Ag conductor paste. Further, the inner layer wiring conductor 14 is screen-printed on the second and lower

green sheets

11b and 11c using a low-melting point metal conductor paste of the same type as the via conductor 13.
[0039]
Further, the first layer (uppermost layer) green sheet 11a is formed by using the above-described low melting point metal conductor paste such as Ag-based, Au-based, or Cu-based for the surface layer wiring conductor 15 such as a pad or a wiring pattern. Print. The surface layer wiring conductor 15 may be printed and fired after the substrate is fired.
[0040]
After the printing process, the

green sheets

11a, 11b, and 11c of the respective layers are stacked and integrated by thermocompression bonding to produce a low-temperature fired ceramic raw substrate. Then, this low-temperature fired ceramic raw substrate is fired at 800 to 1000 ° C. (preferably 900 ° C. or less), and the

green sheets

11a, 11b and 11c of each layer, the via conductor 13, the inner layer wiring conductor 14 and the surface layer wiring conductor 15 are simultaneously formed. Firing to produce a low-temperature fired ceramic multilayer substrate.
[0041]
The composition of the low-temperature fired ceramic multilayer substrate after firing is SiO₂: 27 to 35.8% by weight, CaO: 9 to 13.7% by weight, B₂O_Three: 3.9 to 5% by weight, Al₂O_Three: 36 to 42.8 wt%, BaO: 4.3 to 13.7 wt%, ZnO: 0.9 to 1.6 wt%, SnO₂: 1.2 to 2.6% by weight.
[0042]
The embodiment (1) described above is characterized in that an appropriate amount of BaO is added to both the glass powder and the aggregate of the low-temperature fired ceramic material forming the

green sheets

11a, 11b, and 11c. Suitable amount of ZnO and SnO₂It is also characterized by the addition of
[0043]
The glass powder to which BaO is added has a characteristic that the Qf value becomes high when crystallized in the firing step. Furthermore, when an appropriate amount of BaO is added to the aggregate, BaO—SiO is used in the firing step.₂-CaO-B₂O_Three-Al₂O_ThreeThere is a tendency that the crystal of the glass of the system tends to precipitate and the amount of the deposited glass increases. As a result, the Qf value of the low-temperature fired ceramic material can be increased to 3000 GHz or more.
[0044]
In addition to BaO, glass materials can contain appropriate amounts of ZnO and SnO.₂Made by adding BaO-SiO₂-CaO-B₂O_Three-Al₂O_Three-ZnO-SnO₂ The system glass has a Qf value higher than that of glass not added with ZnO, and ZnO plays a role of lowering the melting point of the glass. In addition, when producing glass powder, SnO₂When SnO is added₂Compared with the case where no is added, the melting point of the glass can be lowered by 30 to 50 ° C., and the production of the glass powder becomes easy.
[0045]
【Example】
Since this inventor performed the test which evaluates the appropriate range of the composition of glass powder, the BaO addition amount of aggregate, and the compounding ratio of glass powder and aggregate, the test result is shown in the following Table 1 and Table 2. Show.
[0046]
[Table 1]

[0047]
[Table 2]

[0048]
In this evaluation test, four types of compositions shown in Table 1 were used.(1)~(4)A glass powder was prepared. In this glass powder production method, a mixture having the composition shown in Table 1 was melted, vitrified and rapidly cooled, and pulverized to produce a glass powder having an average particle size of about 10 μm.
[0049]
The aggregate used in this test is Al without adding BaO.₂O_ThreeOnly aggregates and aggregates containing 0.5%, 1.0%, 1.5%, 2.0% and 3.0% by weight of BaO based on the total weight of the low-temperature fired ceramic material. used.
[0050]
These glass powders and aggregates are mixed at a blending ratio shown in Table 2 to produce a low-temperature fired ceramic material, and a solvent, an acrylic resin (binder), and a plasticizer are blended into the low-temperature fired ceramic material. The slurry was sufficiently mixed by stirring, and this slurry was tape-formed by the doctor blade method and dried to prepare a green sheet having a thickness of 0.1 mm.
[0051]
Thereafter, 12 green sheets were laminated and thermocompression bonded, and then cut into a size of 10.0 mm × 50.0 mm to prepare a sample substrate. And this sample board | substrate was baked on the conditions of 900 degreeC and a 30-minute hold | maintenance in air | atmosphere, and the quality of sintering was evaluated. Further, for the sintered sample substrate, the bending strength of the sample substrate was measured by a bending test. As a result, as shown in Table 2, measured values of sinterability and bending strength of 17 types of samples # 1 to # 17 were obtained.
[0052]
On the other hand, the Qf values of the samples # 1 to # 17 were measured as follows. A low-temperature fired ceramic material having the composition of each sample # 1 to # 17 was molded into a cylindrical shape having a diameter of 15 mm by a die press to prepare a sample, and this sample was fired in the atmosphere at 930 ° C. for 30 minutes. . Then, using the sintered sample, the Q value and the resonance frequency f were measured by the dielectric resonance method, and the Qf value was calculated. This Qf value serves as an index indicating the adaptability to signal processing at higher speeds and higher frequencies, and the higher the Qf value, the easier the response to higher speeds and higher frequencies. A conventional glass composite low-temperature fired ceramic material has a Qf value of about 2000 GHz, but preferably has a high Qf value of 3000 GHz or more in order to cope with the recent rapid development of high speed and high frequency.
[0053]
The acceptance criteria in this evaluation test are that the sinterability is good, the flexural strength is 170 MPa or more, and the Qf value is 3000 GHz or more. It evaluated as ((circle)), and if there was any condition which does not satisfy any one, it evaluated as disqualified (x).
[0054]
Composition of Table 1(1)Samples # 1 and # 2 using the glass powder of No. were both rejected (x). Also composition(2)~(4)Samples # 3 to # 17 using the glass powder of No. 2 were evaluated as acceptable (◯) and rejected (x) depending on the amount of BaO added to the aggregate and the mixing ratio of the glass powder and the aggregate.
[0055]
From this, the composition of the glass powder is shown in Table 1.(2)~(4)It was found that the range of was appropriate. Of Table 1(2)~(4)The composition of the glass powder was SiO2: 45-55 wt%, CaO: 15-21 wt%, B2O3: 6.5-7.7 wt%, Al2O3: 4. wt% with respect to the total weight of the glass powder. 2 to 5.1% by weight, BaO: 6.4 to 18% by weight, ZnO: 1.5 to 2.5% by weight, SnO2: 2 to 4% by weight.
[0056]
In this case, if the amount of BaO added to the glass powder is less than 6.4% by weight, the effect of adding BaO is small and the improvement in Qf value is small. On the contrary, when the BaO addition amount of the glass powder is more than 18% by weight, vitrification becomes difficult. Therefore, the appropriate range of the BaO addition amount of the glass powder is considered to be 6.4 to 18% by weight.
[0057]
In addition, ZnO in the glass powder serves to increase the Qf value and lower the melting point of the glass. When ZnO in the glass powder is less than 1.5% by weight, the melting point of the glass becomes 1400 ° C. or higher. On the other hand, when ZnO is more than 2.5% by weight, vitrification becomes difficult. Therefore, if ZnO is 1.5 to 2.5% by weight, the glass melting point can be lowered appropriately to facilitate vitrification.
[0058]
In addition, SnO in glass powder₂Is less than 2% by weight, the electrical properties deteriorate, and SnO₂When the amount is more than 4% by weight, the thermal expansion increases. Therefore, SnO₂When the content is 2 to 4% by weight, electrical characteristics and thermal expansion characteristics are improved.
[0059]
If the CaO content in the glass powder is less than 15% by weight, nSiO₂・ CaO ・ Al₂O_ThreePrecipitation of crystals in the system is reduced and the required strength cannot be obtained. On the contrary, if the CaO content is more than 21% by weight, the glass melting point becomes too low. Accordingly, if CaO is 15 to 21% by weight, the glass melting point can be made high and moderately low.
[0060]
In addition, SiO in glass powder₂Is less than 45% by weight, nSiO₂・ CaO or BaO ・ SiO₂Precipitation of crystals in the system is reduced and the required strength cannot be obtained. Conversely, SiO₂When it is more than 55% by weight, vitrification becomes difficult. Therefore, SiO₂If it is 45 to 55 weight%, vitrification can be made easy, ensuring intensity | strength.
[0061]
In general, SiO₂And CaO and BaO alone result in a glass with a high melting point, so B as an additive to lower the melting point₂O_ThreeNeed to be added. B in glass powder₂O_ThreeIs less than 6.5% by weight, it becomes difficult to vitrify at 1400 ° C. or lower. Conversely, B₂O_ThreeIs more than 7.7% by weight, the required strength cannot be obtained. Therefore, B₂O_ThreeIs 6.5 to 7.7% by weight, the required strength can be ensured while the glass melting point is appropriately lowered.
[0062]
In addition, Al in glass powder₂O_ThreePlays a role in lowering the melting point of glass, so Al₂O_ThreeIf it is less than 4.2% by weight, the melting point of the glass becomes 1400 ° C. or higher. Conversely, Al₂O_ThreeIs more than 5.1% by weight, it becomes difficult to vitrify. Therefore, Al₂O_ThreeIf it is 4.2 to 5.1 weight%, glass melting point can be lowered | hung moderately and vitrification can be made easy.
[0063]
Next, an appropriate range of the BaO addition amount of the aggregate will be considered. Al without adding BaO₂O_ThreeThe sample using only the aggregate had a Qf value of less than 3000 GHz or poor sintering, and was evaluated as rejected (x). In addition, the samples where the BaO addition amount of the aggregate is 0.5% by weight, 1.0% by weight, and 2.0% by weight all have a Qf value of 3000 GHz or more, good sinterability, and a bending strength of 170 MPa or more. It was evaluated as a pass (○). However, Sample # 7, in which the BaO addition amount of the aggregate was 3.0% by weight, was evaluated as rejected (x) because the bending strength decreased to 165 MPa and did not satisfy the acceptance criteria (170 MPa or more). From this, the appropriate range of the BaO addition amount of the aggregate is considered to be 0.5 to 2.0% by weight.
[0064]
Next, the appropriate range of the mixing ratio of glass powder and aggregate will be considered. In this test, the compounding ratio of the glass powder was set to 55 to 70% by weight, and the aggregate was set to 30 to 45% by weight. All of the samples of glass powder: 55 wt% and aggregate: 45 wt% were evaluated as rejected (x) due to lack of glass and poor sintering. In addition, the samples of glass powder: 70% by weight and aggregate: 30% by weight are not satisfactory because the aggregate is insufficient, the bending strength is reduced to 150 MPa or less, and the acceptance criteria (170 MPa or more) are not satisfied. It was evaluated as a pass (x).
[0065]
On the other hand, in the case of glass powder: 60 to 65% by weight and aggregate: 35 to 40% by weight, for the sample in which the BaO addition amount of the aggregate is in an appropriate range (0.5 to 2.0% by weight), The conditions of the acceptance criteria (sinterability: good, bending strength> 170 MPa, Qf value> 3000 GHz) were satisfied, and the product was evaluated as acceptable (◯). From this, it is considered that the appropriate ranges of the mixing ratio of the glass powder and the aggregate are glass powder: 60 to 65% by weight and aggregate: 35 to 40% by weight.
[0066]
[Embodiment (2)] In the embodiment (1), an appropriate amount of BaO is added to both the aggregate of the low-temperature fired ceramic material and the glass powder. However, in the embodiment (2) described below, the low-temperature fired ceramic material is used. BaO is added only to the aggregate of the ceramic material, SrO is added to the glass powder instead of BaO, and accordingly, the blending ratio of each component of the glass powder is adjusted.
[0067]
Also in this embodiment (2), the low-temperature fired ceramic material for forming the green sheet is Al.₂O_Three(Alumina) -based aggregate: 35-40% by weight and SiO₂-CaO-B₂O_Three-Al₂O_ThreeGlass powder of the system: a mixture of 60 to 65% by weight is used.
[0068]
The aggregate of the low-temperature fired ceramic material is BaO: 0.5 to 2.0% by weight with respect to the total weight of the low-temperature fired ceramic material.₂O_Three: 33 to 39.5% by weight.
[0069]
The glass powder is composed of SiO2 with respect to the total weight of the glass powder.₂: 47 to 55 wt%, CaO: 10 to 14.4 wt%, B₂O_Three: 6.5 to 7.2% by weight, Al₂O_Three: 4.2 to 5.0% by weight, SrO: 11 to 18.8% by weight, ZnO: 4.5 to 5.5% by weight, SnO₂: SrO-SiO containing 2.0 to 4.3 wt%, impurities: 2 wt% or less₂-CaO-B₂O_Three-Al₂O_Three-ZnO-SnO₂Glass powder of the system is used.
[0070]
Using the slurry of the low-temperature fired ceramic material having this composition, a green sheet is formed by the same method as in the embodiment (1), and the conductive pattern printing, green sheet lamination, and firing steps are sequentially performed, and the low-temperature fired ceramic is obtained. A multilayer substrate is manufactured.
[0071]
The composition of the low-temperature fired ceramic multilayer substrate after firing is SiO₂: 28.2 to 35.8 wt%, CaO: 6.0 to 9.4 wt%, BaO: 0.5 to 2.0 wt%, B₂O_Three: 3.9 to 4.7% by weight, Al₂O_Three: 32.5 to 42.8% by weight, SrO: 6.6 to 12.2% by weight, ZnO: 2.7 to 3.6% by weight, SnO₂ : 1.2 to 2.8% by weight.
[0072]
In this embodiment (2) described above, BaO is added only to the aggregate of the low-temperature fired ceramic material forming the green sheet, and the glass powder is characterized in that SrO is added instead of BaO. Appropriate amounts of ZnO and SnO in glass powder₂It is also characterized by the addition of
[0073]
The glass powder to which SrO is added has a characteristic that the bending strength is increased when it is crystallized in the firing step. Furthermore, when an appropriate amount of BaO is added to the aggregate, BaO—SrO—SiO is used in the firing step.₂There is a tendency that the crystal of the glass of the system tends to precipitate and the amount of the deposited glass increases. As a result, the Qf value of the low-temperature fired ceramic material can be increased to 3000 GHz or more.
[0074]
In addition to SrO, glass materials can contain appropriate amounts of ZnO and SnO.₂Made by adding SrO-SiO₂-CaO-B₂O_Three-Al₂O_Three-ZnO-SnO₂ The system glass has a Qf value higher than that of glass not added with ZnO, and ZnO plays a role of lowering the melting point of the glass. In addition, when producing glass powder, SnO₂When SnO is added₂Compared with the case where no is added, the melting point of the glass can be lowered by 30 to 50 ° C., and the production of the glass powder becomes easy.
[0075]

【Example】
Regarding the low-temperature fired ceramic material having the composition of the present embodiment (2), the present inventor conducted a test for evaluating an appropriate range of the composition of the glass powder, the amount of BaO added to the aggregate, and the mixing ratio of the glass powder and the aggregate. The test results are shown in Tables 3 and 4 below.
[0076]
[Table 3]

[0077]
[Table 4]

[0078]
In this evaluation test, four types of compositions shown in Table 3 were used.(1)~(4)A glass powder was prepared. In this glass powder production method, a mixture having the composition shown in Table 3 was melted, vitrified and rapidly cooled, and pulverized to produce a glass powder having an average particle size of about 10 μm.
[0079]
The aggregate used in this test is Al without adding BaO.₂O_ThreeOnly aggregates and aggregates containing 0.5%, 1.0%, 1.5%, 2.0% and 3.0% by weight of BaO based on the total weight of the low-temperature fired ceramic material. used.
[0080]
These glass powders and aggregates are mixed at a blending ratio shown in Table 4 to produce a low-temperature fired ceramic material. The low-temperature fired ceramic material is blended with a solvent, an acrylic resin (binder), and a plasticizer. The slurry was sufficiently mixed by stirring, and this slurry was tape-formed by the doctor blade method and dried to prepare a green sheet having a thickness of 0.1 mm.
[0081]
Thereafter, 12 green sheets were laminated and thermocompression bonded, and then cut into a size of 10.0 mm × 50.0 mm to prepare a sample substrate. And this sample board | substrate was baked on the conditions of 900 degreeC and a 30-minute hold | maintenance in air | atmosphere, and the quality of sintering was evaluated. Further, for the sintered sample substrate, the bending strength of the sample substrate was measured by a bending test. As a result, as shown in Table 4, measured values of sinterability and bending strength of 17 types of samples # 21 to # 37 were obtained. In addition, the measuring method of the Qf value of each sample # 21- # 37 is the same as the said embodiment (1).
[0082]
The acceptance criteria in this evaluation test are that the sinterability is good, the bending strength is 200 MPa or more, and the Qf value is 3000 GHz or more. It evaluated as ((circle)), and if there was any condition which does not satisfy any one, it evaluated as disqualified (x).
[0083]
Composition of Table 3(1)Samples # 21 and # 22 using the glass powder were rejected (x). Also composition(2)~(4)Samples # 23 to # 37 using the glass powder of No. 2 were evaluated as pass (◯) and fail (x) depending on the amount of BaO added to the aggregate and the mixing ratio of the glass powder and the aggregate.
[0084]
From this, the composition of the glass powder is shown in Table 3.(2)~(4)It was found that the range of was appropriate. Of Table 3(2)~(4)The composition of the glass powder is SiO, based on the total weight of the glass powder.₂: 47 to 55 wt%, CaO: 10 to 14.4 wt%, B₂O_Three: 6.5 to 7.2% by weight, Al₂O_Three: 4.2 to 5.0% by weight, SrO: 11 to 18.8% by weight, ZnO: 4.5 to 5.5% by weight, SnO₂: Within the range of 2 to 4.3% by weight.
[0085]
In this case, when the amount of SrO added to the glass powder is less than 11% by weight, the effect of adding SrO is small and the range of improvement in bending strength is small. On the contrary, when the SrO addition amount of the glass powder is more than 18.8% by weight, vitrification becomes difficult. Therefore, the appropriate range of the SrO addition amount of the glass powder is considered to be 11 to 18.8% by weight.
[0086]
In addition, ZnO in the glass powder serves to increase the Qf value and lower the melting point of the glass. If ZnO in the glass powder is less than 4.5% by weight, the melting point of the glass becomes 1400 ° C. or higher. On the other hand, when ZnO is more than 5.5% by weight, vitrification becomes difficult. Therefore, if ZnO is 4.5 to 5.5% by weight, the glass melting point can be lowered appropriately to facilitate vitrification.
[0087]
In addition, SnO in glass powder₂Is less than 2% by weight, the electrical properties deteriorate, and SnO₂When the amount is more than 4.3% by weight, the thermal expansion increases. Therefore, SnO₂When the content is 2 to 4.3% by weight, the electrical characteristics and the thermal expansion characteristics are improved.
[0088]
Further, when CaO in the glass powder is less than 10% by weight, nSiO₂・ CaO ・ Al₂O_ThreePrecipitation of crystals in the system is reduced and the required strength cannot be obtained. On the contrary, when CaO is more than 14.4% by weight, the glass melting point becomes too low. Accordingly, if CaO is 10 to 14.4% by weight, the glass melting point can be made high and moderately low.
[0089]
In addition, SiO in glass powder₂Is less than 47% by weight, nSiO₂・ CaO or SrO ・ SiO₂Precipitation of crystals in the system is reduced and the required strength cannot be obtained. Conversely, SiO₂When it is more than 55% by weight, vitrification becomes difficult. Therefore, SiO₂If it is 47 to 55 weight%, vitrification can be made easy, ensuring intensity | strength.
[0090]
In general, SiO₂And CaO and SrO alone result in a glass with a high melting point, so B as an additive to lower the melting point₂O_ThreeNeed to be added. B in glass powder₂O_ThreeIs less than 6.5% by weight, it becomes difficult to vitrify at 1400 ° C. or lower. Conversely, B₂O_ThreeIs more than 7.2% by weight, the required strength cannot be obtained. Therefore, B₂O_ThreeIs 6.5 to 7.2% by weight, the required strength can be ensured while the glass melting point is appropriately lowered.
[0091]
In addition, Al in glass powder₂O_ThreePlays a role in lowering the melting point of glass, so Al₂O_ThreeIf it is less than 4.2% by weight, the melting point of the glass becomes 1400 ° C. or higher. Conversely, Al₂O_ThreeWhen it is more than 5.0% by weight, vitrification becomes difficult. Therefore, Al₂O_ThreeIf it is 4.2 to 5.0 weight%, glass melting point can be lowered | hung moderately and vitrification can be made easy.
[0092]
Next, an appropriate range of the BaO addition amount of the aggregate will be considered. Al without adding BaO₂O_ThreeThe sample using only the aggregate had a Qf value of less than 3000 GHz or poor sintering, and was evaluated as rejected (x). In addition, the samples with the BaO addition amount of the aggregate of 0.5% by weight, 1.0% by weight, and 2.0% by weight all have a Qf value of 3000 GHz or more, good sinterability, and a bending strength of 200 MPa or more. And passed (○). However, Sample # 27, in which the BaO addition amount of the aggregate was 3.0% by weight, was evaluated as rejected (x) because the bending strength decreased to 170 MPa and did not satisfy the acceptance criteria (200 MPa or more). From this, the appropriate range of the BaO addition amount of the aggregate is considered to be 0.5 to 2.0% by weight.
[0093]
Next, the appropriate range of the mixing ratio of glass powder and aggregate will be considered. In this test, the compounding ratio of the glass powder was set to 55 to 70% by weight, and the aggregate was set to 30 to 45% by weight. All of the samples of glass powder: 55 wt% and aggregate: 45 wt% were evaluated as rejected (x) due to lack of glass and poor sintering. In addition, the samples of glass powder: 70% by weight and aggregate: 30% by weight are not satisfactory because the aggregate is insufficient, the bending strength is reduced to 150 MPa or less, and the acceptance criteria (200 MPa or more) are not satisfied. It was evaluated as a pass (x).
[0094]
On the other hand, in the case of glass powder: 60 to 65% by weight and aggregate: 35 to 40% by weight, for the sample in which the BaO addition amount of the aggregate is in an appropriate range (0.5 to 2.0% by weight), The conditions of the acceptance criteria (sinterability: good, bending strength> 200 MPa, Qf value> 3000 GHz) were satisfied, and the product was evaluated as acceptable (◯). From this, it is considered that the appropriate ranges of the mixing ratio of the glass powder and the aggregate are glass powder: 60 to 65% by weight and aggregate: 35 to 40% by weight.
[0095]
【The invention's effect】
As apparent from the above description, the low-temperature fired ceramic material according to claim 1 of the present invention has an appropriate amount of BaO added to both the aggregate and the glass powder. In addition to being able to cope with the recent rapid development of high speed and high frequency, the mechanical strength necessary for securing the reliability of the substrate can be provided.
[0096]
In addition to BaO, suitable amounts of ZnO and SnO are used as glass raw materials.₂Thus, the Qf value can be further increased, the melting point of the glass can be lowered, and the production of the glass powder is facilitated.
[0097]
Claims2Then, the aggregate Al₂O_ThreeSince the content is 33 to 39.5% by weight based on the total weight of the low-temperature fired ceramic material, it is possible to ensure the bending strength and sinterability that can withstand practical use.
[0098]
Claims3Then, since the ceramic raw substrate formed using the low-temperature fired ceramic material having the above-mentioned composition is fired at 800 to 1000 ° C. to produce the low-temperature fired ceramic substrate, it can cope with recent high speed and high frequency. A high-quality, low-temperature fired ceramic substrate having both the Qf value and the substrate strength necessary for ensuring reliability can be manufactured.
[0099]
Claims4Then, BaO is added only to the aggregate of the low-temperature fired ceramic material, and SrO is added to the glass powder instead of BaO, so that the mechanical strength of the substrate can be further improved, and the Qf value of the low-temperature fired ceramic material can be increased. The frequency can be increased to 3000 GHz or more, and it is possible to cope with recent high speed and high frequency.
[0100]
In addition, glass materials with appropriate amounts of ZnO and SnO₂Thus, the Qf value can be further increased, the melting point of the glass can be lowered, and the production of the glass powder is facilitated.
[0101]
Claims5Then, the aggregate Al₂O_ThreeSince the content is 33 to 39.5% by weight based on the total weight of the low-temperature fired ceramic material, it is possible to ensure the bending strength and sinterability that can withstand practical use.
[0102]
Claims6Then, since the ceramic raw substrate formed using the low-temperature fired ceramic material having the above-mentioned composition is fired at 800 to 1000 ° C. to produce the low-temperature fired ceramic substrate, it can cope with recent high speed and high frequency. A high-quality, low-temperature fired ceramic substrate having both the Qf value and the substrate strength necessary for ensuring reliability can be manufactured.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a low-temperature fired ceramic multilayer substrate showing an embodiment (1) of the present invention.
[Explanation of symbols]
11a, 11b, 11c. . . Low temperature fired ceramic green sheet, 12. . . Via hole, 13. . . Via conductors, 14. . . Inner layer wiring conductor, 15. . . Surface wiring conductor.

Claims

Aggregate mainly composed of Al ₂ O ₃ : 35 to 40% by weight and SiO ₂ —CaO—B ₂ O ₃ —Al ₂ O ₃ glass powder: 60 to 65% by weight firing the ceramic material, the aggregate, the BaO against low-temperature co-fired ceramic material total weight containing 0.5 to 2.0 wt%, the glass powder, SiO ₂ and with respect to the glass powder to the total weight: 45 55 wt%, CaO: 15 to 21 wt%, B ₂ O _3: 6.5~7.7 wt%, Al ₂ O _3: 4.2~5.1 wt%, BaO: 6.4~18 A low-temperature fired ceramic material comprising: wt%, ZnO: 1.5 to 2.5 wt%, SnO ₂ : 2 to 4 wt%, impurities: 2 wt% or less.

The low-temperature fired ceramic material according to claim 1, wherein the aggregate contains 33 to 39.5 wt% of Al ₂ O ₃ with respect to the total weight of the low-temperature fired ceramic material.

A low-temperature fired ceramic substrate obtained by firing a ceramic raw substrate formed using the low-temperature fired ceramic material according to claim 1 or 2 at 800 to 1000 ° C.

Aggregate mainly composed of Al ₂ O ₃ : 35 to 40% by weight and SiO ₂ —CaO—B ₂ O ₃ —Al ₂ O ₃ glass powder: 60 to 65% by weight firing the ceramic material, the aggregate, the BaO against low-temperature co-fired ceramic material total weight containing 0.5 to 2.0 wt%, the glass powder, SiO ₂ for the said glass powder total weight: 47 55 wt%, CaO: 10 to 14.4 wt%, SrO: 11 to 18.8 wt%, B ₂ O _3: 6.5~7.2 wt%, Al ₂ O _3: 4.2~5 A low-temperature fired ceramic material comprising: 0.0 wt%, ZnO: 4.5 to 5.5 wt%, SnO ₂ : 2.0 to 4.3 wt%, impurities: 2 wt% or less.

The aggregate, low temperature co-fired ceramic material according to claim 4, wherein the containing Al ₂ O ₃ with respect to low-temperature co-fired ceramic material total weight from 33 to 39.5 wt%.

A low-temperature fired ceramic substrate obtained by firing a ceramic raw substrate formed using the low-temperature fired ceramic material according to claim 4 or 5 at 800 to 1000 ° C.