磁控溅射成膜温度对纯铝薄膜小丘生长以及薄膜晶体管阵列工艺良率的影响

Effect of sputter temperature on hillock formation in pure Al film and thin film transistor array process yield

纯铝薄膜被广泛用作TFT-LCD的金属电极,但纯铝薄膜在热工艺中容易产生小丘,对TFT的阵列工艺的良率有较大影响。本文用磁控溅射的方法在不同温度下沉积纯铝薄膜作为薄膜晶体管的栅极,并通过电学检测、扫描电子显微镜和应力测试等方法对不同温度下沉积的纯铝薄膜的小丘生长情况进行了研究。实验结果表明:纯铝成膜温度提高,薄膜的晶粒尺寸增大,退火后产生小丘的密度和尺寸明显降低,温度-应力曲线中屈服点温度也相应提高。量产中适当提高成膜温度,可以有效抑制小丘的发生,提高TFT阵列工艺的量产良率。

The pure Al films were widely used as the thin film transistor （TFT） gate electrode,but the TFT mass production yield is easily influenced by hillock phenomenon happened in pure Al film in heating process.The pure Al films were prepared at different deposition temperature by the magnetron sputtering in the experiment.The hillocks and the pure Al films were characterized by electrical test instruments,the scan electron microscopy （SEM） and stress tester.It was found that the hillock density and size reduced when the deposition temperature increased because of the larger grain size of the pure Al films and the higher yield temperature point in the stress temperature curve.So the deposition temperature should be advisably increased to limit the hillock quantity for improving TFT array process yield.