Area selective deposition via atomic layer deposition (ALD) has proven its utility in elementary nanopatterning processes. In the case of complex 3D patterned substrates, selective deposition processes lead to vertical sidewall coverage only, or top and bottom horizontal surface coverage only, to enable advanced nanopatterning and further miniaturization of microelectronic devices. While many fabrication strategies for vertical only Topographically Selective Deposition (TSD) have already been developed, the horizontal TSD case needs further attention. In this work, we propose a versatile route for the TSD on 3D top and bottom horizontal surfaces along with a proof-of-concept for such selective Ta₂O₅ thin film deposition. The strategy at stake relies on a plasma enhanced atomic layer deposition process assisted by energetic ion bombardment during the plasma step and followed by a postgrowth wet etching step. The effectiveness of this strategy is based on a careful adjustment of processing temperatures purposely set at low temperature, most probably below the ALD temperature window. Anisotropic ion bombardment via substrate biasing during the plasma step provides an extra amount of thermal energy only to exposed horizontal surfaces, which in turn enables a selective densification of the thin film under growth. The difference in thin film density on horizontal and vertical surfaces enables the property-selective etching of vertical surfaces, generating horizontal TSD. A proof-of-concept for such low temperature TSD is shown in the case of 3D trenched substrates with an aspect ratio of 14.

中文翻译：

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通过离子轰击辅助的等离子体增强原子层沉积进行低温地形选择沉积

通过原子层沉积（ALD）进行区域选择性沉积已证明其在基本纳米图案化工艺中的实用性。在复杂的3D图案化基板的情况下，选择性沉积过程仅导致垂直侧壁覆盖，或仅导致顶部和底部水平表面覆盖，以实现先进的纳米图案化和微电子设备的进一步小型化。尽管已经开发出了许多仅用于垂直形貌选择性沉积（TSD）的制造策略，但水平TSD情况需要进一步关注。在这项工作中，我们为3D顶部和底部水平面上的TSD提出了一条通用的路线，并提出了针对此类选择性Ta ₂ O _5的概念证明。薄膜沉积。关键的策略依赖于等离子体增强的原子层沉积过程，该过程由在等离子体步骤期间进行的高能离子轰击以及随后的后生长湿法蚀刻步骤辅助。该策略的有效性是基于对故意设置为低温（最有可能低于ALD温度窗口）的加工温度的仔细调整。在等离子步骤中，通过基板偏压进行的各向异性离子轰击仅向暴露的水平表面提供了额外的热能，从而使生长中的薄膜得以选择性地致密化。水平和垂直表面上薄膜密度的差异使得可以对垂直表面进行属性选择性蚀刻，从而产生水平TSD。