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Method and structure for feature size dependent differential film growth

IP.com Disclosure Number: IPCOM000235783D
Publication Date: 2014-Mar-25
Document File: 3 page(s) / 82K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for growing a thin film with a faster growth rate at the bottom of smaller holes/trenches compared to wide flat areas or larger holes/trenches. This method accommodates different design structures with various critical dimensions.

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Method and structure for feature size dependent differential film growth

As feature sizes shrink and aspect ratios become more challenging, conventional film growth techniques, such as Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), and Atomic Layer Deposition (ALD), cannot satisfy the needs of different design structures with various critical dimensions (CD). For example, PVD type techniques deposit films much thicker on top flat surfaces or small aspect ratio holes compared to small CD, high aspect ratio structures. ALD/CVD type growth can fill challenging small and deep holes/trenches; however, due to high conformality (i.e., sidewall growth), film pinches off when the CD is small.

One solution to engineer film growth on different devices is to use masks; however, this increases the cost of manufacturing.

The novel contribution is a method for growing a thin film with a faster growth rate at the bottom of smaller holes/trenches compared to wide flat areas or larger holes/trenches. This achieves a unique structure that shows a thicker film (e.g., material X) at the bottom of the small critical dimensions; meanwhile, the same material (X) is thinner on the top and on the sidewalls as well as in wider holes/trenches.

The method utilizes the gas cluster ion implant process, which can directionally grow thin films depending on the process gas. For example, SiH4 gas clusters grow Si, WF6 clusters can grow W films, etc.

Gas clusters that impinge on...