TiN薄膜掠射侧倾法应力测试

The Stress Measurement for TiN Films by Glancing Method

由于薄膜厚度很薄 ,使得在应用传统 X射线法测试薄膜应力时 ,存在透入深度过深且衍射强度不够的缺点 ;而且一般气象沉积膜都存在择优取向的情况 ,应用常规法 (或侧倾法 )测试时易发生 sin2 ψ曲线弯曲现象 .准聚焦衍射几何也使得常规法在无应力情况下产生正、负 ψ的 sin2 ψ曲线发生分离现象 .故与传统方法相比 ,掠射侧倾法具有透入深度浅、透入深度随 ψ角变化不大以及对织构影响不敏感以及没有无应力试样的正、负 ψ曲线分离等优点 ,所以掠射侧倾法是一种更适于薄膜应力测量的测试方法 .本文应用掠射侧倾法测量了 PVD和 PCVD工艺的 Ti N薄膜的内应力情况 ,结果表明制备工艺对于气象沉积膜内的应力状态有较大影响 ,而且薄膜内的应力状态比较复杂 ,一般处于三向应力状态 .

The traditional sin 2 ψ methods for X ray stress analysis, such as Bragg Brentano and side incline methods, have some disadvantages when they are applied to the measurement of residual stresses in thin films, where the penetration depth is very deep and the intensity is too low to form the diffraction peaks. The thin films prepared by vapor deposition are always anisotropy. It can lead the curve of sin 2 ψ to show appreciable oscillation in the range of the low ψ angle. In addition, Bragg Brentano method can be affected by the diffraction geometry of the para focusing method, and the positive and the negative ψ parts of sin 2 ψ curve of the sample would split under zero stress condition. Compared with Bragg Brentano and side incline methods, glancing method is much better, its pene tration depth is very thin and it changes little when the ψ angle increases. In addition, the anisotropy of thin films and the diffraction geometry can hardly affect the results obtained by glancing method. So the glancing method is a good way for measuring the residual stress in thin films. By the method, we found that the stress state is rather complex in thin films and is always a tri axial stress state.