氮化铝-铝复合封装基板的制备

采用磁控溅射法在阳极氧化预处理过的铝板上沉积氮化铝薄膜,制备氮化铝-铝复合基板。制备的氮化铝为非晶态,抗电强度超过700 V/μm,阳极氧化铝抗电强度达75 V/μm。当阳极氧化铝膜厚约10μm、氮化铝膜约1μm时,制备的复合封装基板击穿电压超过1350 V,绝缘电阻率1.7×106 MΩ·cm,氮化铝与铝板的结合强度超过8 MPa;阳极氧化铝膜作为缓冲层有效缓解了氮化铝与铝热膨胀系数失配的问题,在260℃热冲击下,铝板未发生形变,氮化铝膜未破裂,电学性能无明显变化。氮化铝与阳极氧化膜的可见光高透性保持了镜面抛光金属铝的高反射率,当该复合基板应用于LED芯片COB封装时,有助于提高封装光效。

The Fabrication of AlN-Al Substrate

AlN-Al composite substrate is fabricated by depositing AlN thin film on the anodized aluminum. The AlN and Anodized Aluminum Oxidation(AAO) film are amorphous and the dielectric strength exceeding 700 V/μm and 75 V/μm, respectively. When the thicknesses of AlN and AAO are 1 μm and 10 μm, the breakdown voltage and resistivity are larger than 1350 V and 1.7×106 MΩ·cm. The bond strength of AlN and Al reaches 8 MPa. AAO film, as a buffer layer, reduces the mismatch of Temperature Expansion Coefficient(TEC) between AlN and Al. Thus, when the temperature of thermal shock reaches 260℃, the aluminum substrate does not deform, and the AlN film not crack. The high transparency of AlN and AAO film keeps the high reflectivity of polished aluminum. Thus AlN-Al substrate can improve the light extraction, when used in the COB package of LED chip.