Diagnostic of Surface Wave Plasma for Oxide Etching in Comparison with Inductive RF Plasma
Diagnostic of Surface Wave Plasma for Oxide Etching in Comparison with Inductive RF Plasma
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DOI：
10.1143/jjap.38.5256
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发表时间：
1999-09
影响因子：
1.5
通讯作者：
H. Kokura;S. Yoneda;Keiji Nakamura;N. Mitsuhira;Moritaka Nakamura;H. Sugai
中科院分区：
文献类型：
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作者：
H. Kokura;S. Yoneda;Keiji Nakamura;N. Mitsuhira;Moritaka Nakamura;H. Sugai
表面波等离子体 (SWP) 和感应耦合等离子体 (ICP) 反应器是高等离子体密度、非磁化源，有望用于下一代蚀刻工艺。我们在 C4F8/Ar 放电中的自由基成分和电子能量分布函数 (EEDF) 方面比较了 2.45 GHz SWP 和 13.56 MHz ICP。在相同的等离子体容器中，在相同的壁温下仔细对两种等离子体进行了比较，其中石英板上的天线耦合器从用于 SWP 的扩展波导更改为用于 ICP 的环形线圈。相同气体条件下相同电子密度下的活性物质测量显示出显着差异。首先，相同电子密度下C4F8的解离度在ICP中比在SWP中更高。其次，相同电子密度下的中性自由基密度（CF3、CF2）在SWP中比在ICP中高几倍，并且ICP具有较高的F自由基密度。第三，从离子组成来看，ICP中Ar+较多，氟碳离子(CmFn+)较少，而SWP中存在大分子离子(C2F4+、C3F3+、C3F5+)。总之，在相同的电子密度下，ICP 比 SWP 更具解离性。这一结果暂时归因于两种等离子体 EEDF 的差异，因为 Ar I 的光学发射光谱表明 ICP 中的高能 (>14 eV) 电子比 SWP 中多 1.5-2 倍。
Surface wave plasma (SWP) and inductively coupled plasma (ICP) reactors are high plasma density, unmagnetized sources that show promise for use in next-generation etching processes. We compare the 2.45 GHz SWP with the 13.56 MHz ICP in terms of the radical composition in C4F8/Ar discharges and the electron energy distribution function (EEDF). A comparison of the two plasmas was carefully made in an identical plasma vessel at the same wall temperature where an antenna coupler on a quartz plate was changed from an expanded waveguide for SWP to a loop coil for ICP. Reactive species measurement at the same electron density under the same gas conditions showed marked differences. First, the dissociation degree of C4F8 at the same electron density is higher in ICP than in SWP. Second, neutral radical densities (CF3, CF2) at the same electron density are several times higher in SWP than in ICP, and ICP has a high F radical density. Third, as regards ionic composition, ICP contains more Ar+ and less fluorocarbon ions (CmFn+), while large molecular ions (C2F4+, C3F3+, C3F5+) exist in SWP. In conclusion, ICP is more dissociative than SWP at the same electron density. This result is tentatively attributed to the difference in the EEDFs of the two plasmas, since optical emission spectroscopy of Ar I suggests 1.5–2 times more high-energy (>14 eV) electrons in ICP than in SWP.