A low stress silicon oxynitride deposition process has been developed in which the average stress level can be tailored by adjusting silane flow in the plasma enhanced chemical vapor deposition reactor. Stress gradients, as might be caused by nonuniform heating or gas distribution, were not found to exist. By volume, the SiON films were found to be approximately 81 silicon dioxide and 19 silicon nitride. Because the films are easily removed in hydrofluoric acid, this composition is ideally suited for use as a hardmask patterning layer on x-ray masks. A reactive ion etch process employing CHF3, O-2, and Ar gases has demonstrated selectivity to Shipley SNR 200 resist of better than 3:1. Smooth pattern transfer into TaSi and TaSiN absorber layers of test features as small as 0.1 mu m has been achieved using SiON as the hardmask layer. Image placement distortions on the order of 15 nm (3 sigma) occur from etching the SiON films on 64 Mbit SRAM x-ray test masks. (C) 1997 American Vacuum Society. References: 12
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机译：已经开发了一种低应力氮氧化硅沉积工艺，其中可以通过调整等离子体增强化学气相沉积反应器中的硅烷流量来定制平均应力水平。没有发现可能由不均匀加热或气体分布引起的应力梯度。按体积计算，SiON薄膜的二氧化硅含量约为81%，氮化硅含量约为19%。由于薄膜在氢氟酸中很容易去除，因此该组合物非常适合用作 X 射线掩模上的硬掩模图案层。采用 CHF3、O-2 和 Ar 气体的反应性离子蚀刻工艺已证明对 Shipley SNR 200 光刻胶的选择性优于 3：1。使用SiON作为硬掩模层，可以平滑地将图案转移到小至0.1μm的测试特征的TaSi和TaSiN吸收层中。在64 Mbit SRAM X射线测试掩模上蚀刻SiON薄膜时，会出现大约15 nm（3 sigma）的图像放置失真。（C） 1997年美国真空学会。[参考资料： 12]
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