US Patent No. 10,485,099

MULTILAYER CERAMIC SUBSTRATE


Patent No. 10,485,099
Issue Date November 19, 2019
Title Multilayer Ceramic Substrate
Inventorship Takahiro Oka, Nagaokakyo (JP)
Yoshitake Yamagami, Nagaokakyo (JP)
Yuki Takemori, Nagaokakyo (JP)
Kazuo Kishida, Nagaokakyo (JP)
Hiromichi Kawakami, Nagaokakyo (JP)
Assignee MURATA MANUFACTURING CO., LTD., Nagaokakyo-Shi, Kyoto-Fu (JP)

Claim of US Patent No. 10,485,099

1. A multilayer ceramic substrate comprising:a plurality of base layers that are laminated containing a low-temperature co-fired ceramic material;
a plurality of first constraint layers which contain a metal oxide that is not completely sintered at a sintering temperature of the low-temperature co-fired ceramic material and which are located between adjacent base layers of the plurality of laminated base layers; and
a protective layer which contains the metal oxide and which is located outermost in a lamination direction of the plurality of laminated base layers and is in contact with an outermost base layer of the plurality of laminated base layers in the lamination direction,
wherein X1>X2, where X1 is a first content of the metal oxide in a surface section of the protective layer and X2 is a second content of the metal oxide in a boundary section of the protective layer that is in contact with the outermost base layer, and
wherein the protective layer includes a second constraint sublayer in contact with the outermost base layer and a covering ceramic sublayer on the second constraint sublayer, and multilayer ceramic substrate further comprises a wiring conductor on the second constraint sublayer, the covering ceramic sublayer is located so as to cover a periphery of the wiring conductor on the second constraint sublayer, the covering ceramic sublayer contains the metal oxide, and a surface of the covering ceramic sublayer has a region having a metal oxide content higher than that of other regions of the covering ceramic sublayer.