薄膜厚度宽带监控中评价函数的修正

Correction of the estimate function in thin-film thickness wideband monitoring

在镀膜过程中,采用宽光谱实时监控薄膜厚度的方法,评价函数的准确计算关系到薄膜厚度的最终监控结果.而薄膜材料的吸收会引起评价函数的失真.本文采用软件的方法,在镀下一层之前,对其评价函数中的理论透射比作以修正,消除已镀层吸收对其的影响,由此逐层进行直至结束.实验结果表明,薄膜厚度监控误差可以达到10-3以下,效果良好,完全可以满足实际需要.

In use of wideband thin_film thickness monitoring during the deposition of layers,whether success or failure of the process depends on correct calculation of the estimate function.The absorption of thin_film material results in distortion of the estimate function.A software method is put forward by the authors.Before the next layer is deposited,the theoritic transmittance is to be corrected to eliminate effect of deposited layer absorption on thickness error.By experiments,the monitoring error of thin_film thickness is reduced to less than 10^(-3) which satisfies the practical requirement.