PROBLEM TO BE SOLVED: To secure sufficient thermal conductivity between an electronic circuit chip and a thermal conductor, while securing insulation properties therebetween in an ultrasonic probe.SOLUTION: In the ultrasonic probe, an ASIC 54 having a back side 54a with conductivity, and a metal rear-side thermal conductor 34 are joined with each other via a composite layer 90b having an insulation function and a thermal conduction function. The composite layer 90b includes: an insulating thin-film-like film 96； a front-side adhesive layer 98 for sticking the film 96 and the ASIC 54； and a rear-side adhesive layer 100 for sticking the film 96 and the rear-side thermal conductor 34. The insulation properties between the ASIC 54 and the rear-side thermal conductor 34 are secured by the film 96. Further, the film 96 is formed of a material with relatively high dielectric strength, so that, even when the film 96 is thinned to substantially several μm, the insulation properties can be secured. The thickness of the film 96 is thinned to substantially several μm to thereby reduce the thickness of the composite layer 90b to substantially several μm-several dozen μm. This configuration can retain the thermal conductivity of the composite layer 90b high.SELECTED DRAWING: Figure 5【課題】超音波プローブ内において、電子回路チップと熱伝導体との絶縁性を担保しつつ、両者間の十分な熱伝導性を確保する。【解決手段】裏面５４ａが導電性であるＡＳＩＣ５４、及び金属製の後側熱伝導体３４が、絶縁機能及び熱伝導機能を有する複合層９０ｂを介して、互いに接合される。複合層９０ｂは、絶縁性の薄膜状のフィルム９６、フィルム９６とＡＳＩＣ５４とを接着する前側接着層９８、及びフィルム９６と後側熱伝導体３４とを接着する後側接着層１００を含んで構成される。フィルム９６によりＡＳＩＣ５４と後側熱伝導体３４との間の絶縁性が担保される。また、フィルム９６を絶縁耐力の比較的高い物質で形成することで、フィルム９６を数μｍ程度に薄くしても絶縁性を担保可能となる。フィルム９６の厚みを数μｍ程度にすることで複合層９０ｂの厚みも数μｍ～数十μｍまで小さくすることが可能になり、複合層９０ｂの熱伝導性が高く維持される。【選択図】図５
