摘要
提出硅片直接键合(SDB)的下列机理:热氧化硅表面的悬挂键在常温下与羟基因形成化学键.两个镜面平整表面互相重合,原子互相以范德瓦斯力互相吸引.在200—400℃,两表面吸附之羟基互相作用形成键合界面的硅醇键.温度高于800℃,硅醇键间发生显著化学聚合反应,形成硅氧键及水.水分子高温下扩散入体内与硅氧化,使键合强度增大,并使键合界面处空洞形成局部真空,有利于空洞消失.水扩散系数随温度而指数增大,在1050℃附近有一转折点,扩散系数增加速率显著减慢.由以上键合机理确定了优化的两阶段键合工艺,制得3英寸直接键合硅片.成功地利用SOI/SDB衬底制备了1—3μm CMOS器件,典型的电子和空穴沟道迁移率为680cm^2/V·sec及320cm^2/V·sec.
A silicon wafer direct bonding mechanism is proposed as follows. Silicon dangling bonds on the thermal oxidized silicon surface adsorb OH groups to form chemical bonds. A pair of these mirror-polisned silicon wafers in contact is attracted by van der Waal's force at room temperature. At 200-400℃, OH groups located on both surfaces interact, and interface silanol bonds are formed between two surfaces. The polymerization of silanol bonds takes place at a temperature above 800℃ to form siloxane (Si-O-Si) and water. Water molecules diffuse through the interface oxide to react with the bulk silicon. It results in an enhancement of bonding strength and in a local vacuum at uncontacted voids and contributes to the elimination of voids. Water molecular diffusion coefficient increases exponentially with temperature and there is a turning point around 1050℃ after which the increasing rate slows down significantly. Based on the above bonding mechanism, an optimized bonding process has been designed and 3' wafers have been directly bonded successfully 1-3μm CMOS devices using the SOI/SDB material have been fabricated and good performance has been shown. Typical values of electron and hole channel mobility at low drain voltage are 680 cm2/V. sec. and 320 cm2/V. sec., respectively.
出处
《应用科学学报》
CAS
CSCD
1990年第4期303-308,共6页
Journal of Applied Sciences
基金
国家自然科学基金资助
