微波基板表面可焊性镀层的制备及性能评估

文中针对低温共烧陶瓷（Low Temperature Co-fired Ceramic, LTCC）微波多层基板高密度布线和多深腔的结构形态，结合化学镀工艺过程及原理，讨论了采用化学镀在LTCC微波多层基板表面制备可焊性镀层的工艺难点。针对某微波多层基板化学镀生产中出现的漏镀和渗镀缺陷，深入分析了各影响因素及作用机理，借助扫描电子显微镜（Scanning Electron Microscope, SEM）、能谱仪（Energy Dispersive Spectrometer, EDS）等微观分析手段，确定了引起漏镀和渗镀缺陷的主要原因，采取酸漂洗、增强玻璃刻蚀条件等措施，解决了漏镀和渗镀的难题。对可焊性镀层的附着力和键合可靠性进行了测试评价，结果表明，金属浆料及可焊性镀层均附着良好，键合强度较高，键合点可靠，能很好地满足微波组件的应用要求。

Preparation and Performance Evaluation of Solderable Coating on Microwave Substrate

Considering the high density of top-layer patterns and the deep cavity structures of LTCC (Low Temperature Co-fired Ceramic) microwave multilayer substrates, combining the process and theory of electroless plating, the key points of solderable coatings deposition by electroless plating on microwave multilayer substrates are discussed in this paper. The factors causing the defects of skip plating and over plating occurred in the electroless plating of a kind of microwave multilayer substrates and the mechanism of the defects are analyzed in detail. By means of SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectrometer) and other microscopic analysis methods, the main causes of the defects are identified. Appropriate solutions such as acid immersion and glass etch conditions strengthening are adopted to avoid the defects. The film adhesion and the wire bonding strengths are tested, the results indicate that the film adhesion and the bonding strengths are competent for the application in microwave components.