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Semiconductor fin with improved profile and surface smoothness

IP.com Disclosure Number: IPCOM000236377D
Publication Date: 2014-Apr-23
Document File: 5 page(s) / 91K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed are integrated methods to improve a semiconductor fin’s profile and surface smoothness following sidewall image transfer (SIT). The approach is to perform an implantation almost parallel to the fin surface, followed by a selective etch or an oxidation in conjunction with oxide etch.

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This is the abbreviated version, containing approximately 69% of the total text.

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Semiconductor fin with improved profile and surface smoothness

FinFET is one of the device options for future Complimentary Metal-Oxide Semiconductor (CMOS) technology. Fins with a straight profile and a smooth surface are critical to minimizing the FinFET device variability that results from fin width variation and achieving high performance by reducing carrier surface scattering.

Fins are usually formed by sidewall image transfer (SIT). Due to patterning variation, fins after SIT processing have the following issues: rough fin surface, tapered fin profile, foot at the bottom of the fin, etc.

Figure 1: Illustration of fin problems following SIT processing

The novel contribution provides several integrated methods to improve the fin profile and surface smoothness. The approach is to perform an implantation almost parallel to the fin surface, followed by a selective etch or an oxidation in conjunction with oxide etch.

Figure 2: A method to improve the fin profile

1. Trim Hard Mask (HM) (optional)

2. Perform an implant with a slightly tilted angle to modify or dope the fin surface (e.g., by fluorine or xenon implantation)

1


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Figure 3: Embodiment #1


Perform an etch to remove the doped fin selective to the undoped fin, resulting in fin with improved profile (more straight and smooth surface)

Figure 4: Embodiment #1 (continued)

Thermal anneal can be performed to heal any implant damage by recrystallization. The thermal anneal can be omitted if the later f...