Deep etching of silicon carbide for micromachining applications: Etch rates and etch mechanisms
Deep etching of silicon carbide for micromachining applications: Etch rates and etch mechanisms
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DOI：
10.1116/1.1387459
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发表时间：
2001-07-01
影响因子：
1.4
通讯作者：
Chabert, P
中科院分区：
文献类型：
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作者：
Chabert, P
已经研究了SF6 Helicon等离子体中4H-SIC的蚀刻速率，这是根据压力，RF功率，偏置电压和基板支架和Helicon源之间的距离的函数。当此距离最小的时候，达到了非常高的蚀刻速率为1.35 mum/min。使用镍掩模时，已经获得了2英寸SIC底物和光滑蚀刻表面的良好均匀性。在高蚀刻速率条件下，选择性SIC/NI约为50。在4H-SIC底物中，通过孔被蚀刻到330 AM的深度。还研究了蚀刻机制在平行板的电容耦合反应器中，我们通过激光诱导的荧光（LIF）检测到SIC在纯SF6等血清中产生的反应离子蚀刻过程中产生的自由基SIF2，CF和CF2。在空间和时间分辨的LIF测量中，用于区分这些物种的气相和蚀刻表面产生。 CF和CF2是主要的蚀刻产物（即主要在蚀刻表面产生），而SIF2自由基主要在气相中产生（可能是通过假定的主要蚀刻产物SIF4的电子撞击解离）。我们将这种差异归因于SIC底物表面上富含碳的层的形成。该层的去除是一个限制步骤，会产生不饱和的CFX（x = 1,2,3）自由基。在我们的条件下，CF2自由基占碳蚀刻总产品的20％。 （c）2001年美国真空学会。
The etch rate of 4H-SiC in a SF6 helicon plasma has been investigated as a function of pressure, rf power, bias voltage and distance between the substrate holder and the helicon source. Very high etch rates of 1.35 mum/min were achieved when this distance is minimum. Good uniformity on 2 in. SiC substrates and smooth etched surfaces free of micromasking have been obtained when using a nickel mask. The selectivity SiC/Ni was found to be about 50 in high etch rate conditions. Via holes have been etched to a depth of 330 Am in 4H-SiC substrates. Etch mechanisms were also studied in a parallel-plate capacitively coupled reactor, We have detected by laser-induced fluorescence (LIF), the radicals SiF2, CF, and CF2 produced during the reactive ion etching of SiC in a pure SF6 plasma. Spatially and temporally resolved LIF measurements were used to distinguish between gas phase and etched surface production of these species. Whereas CF and CF2 are primary etch products (i.e., mainly produced at the etched surface), the SiF2 radicals are mainly produced in the gas phase (probably by electron impact dissociation of SiF4, the putative major etch product). We attribute this difference to the formation of a carbon-rich layer on the SiC substrate surface. The removal of this layer, which is a rate-limiting step, produces unsaturated CFx (x = 1,2,3) radicals. The CF2 radical represents up to 20% of the total carbon etch products under our conditions. (C) 2001 American Vacuum Society.