PCM测试参数与CCD工艺关系研究

Study on PCM Parameters Test in CCD Process

摘要:

PCM(Process Control Monitor)是一种反映生产线工艺状况的质量监控技术。文章围绕影响电荷耦合器件(CCD)工艺中PCM测试结果的工艺因素展开研究,并对PCM测试结果进行统计分析,以达到测试结果用于工艺改进的目的,并最终获取最佳工艺条件。结果表明:低压化学气相沉积(LPCVD)温度为700℃、膜厚为580nm时的方块电阻为18Ω/□；孔工艺采用干法刻蚀CF₄流量为15cm³/min、CHF₃流量为45cm³/min下的接触电阻为7Ω；栅下埋沟注入磷离子能量为250keV、剂量为2.5×10¹²atom/cm²时,MOS管阈值电压为-8.5V；二次铝刻蚀主刻蚀采用Cl₂流量为90cm³/min,BCl₃流量为45cm³/min,N₂流量为30cm³/min可有效避免因残留物引起的金属同层漏电。

Abstract:

Process control monitor (PCM) is a key quality monitoring technique reflecting the process status of the production line. In this paper, it focuses on the factors affecting the test results of PCM in the fabrication process of charge coupled device (CCD), and the test results of PCM is statistically analyzed. The results show that, the sheet resistance is 18Ω/□ when the deposition temperature of LPCVD is 700℃ and the film thickness is 580nm. The contact resistance is 7Ω when the hole process adopts dry etching with CF₄ flow rate of 15cm³/min and CHF₃ flow rate of 45cm³/min. The threshold voltage of the MOS transistor is -8.5V when the energy and dose of phosphorus ion implanted into the buried channel under the gate are 250keV and 2.5×10¹²atoms/cm², respectively. It can effectively avoid the metal leakage caused by residues when the secondary aluminum etching adopts Cl₂ flow rate of 90cm³/min, BCl₃ flow rate of 45cm³/min and N₂ flow rate of 30cm³/min.