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Design of FinFET SRAM fin using Directed Self Assembly

IP.com Disclosure Number: IPCOM000236105D
Publication Date: 2014-Apr-04
Document File: 5 page(s) / 367K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a Static Random Access Memory (SRAM) design that uses directed self-assembly (DSA) with single pitch grating, while meeting the scaling trend. This design allows DSA into SRAM fin Field Effect Transistor (finFET) design space. This description includes a method for converting the existing SRAM design into a DSA-favorable design.

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Page 01 of 5

Title

Design of FinFET SRAM fin using Directed Self Assembly

Abstract

Disclosed is a Static Random Access Memory (SRAM) design that uses directed self- assembly (DSA) with single pitch grating, while meeting the scaling trend. This design allows DSA into SRAM fin Field Effect Transistor (finFET) design space. This description includes a method for converting the existing SRAM design into a DSA- favorable design.

Problem

The directed self-assembly (DSA) technique is an alternative way to extend the scaling trend in lithography. The technique uses a guide pattern to direct the Block-CO Polymer (BCP) into the desired pattern, especially for pattern density multiplication and defect rectification.

Due to the chemistry of this DSA technique, however, only ultra-regular designs are available for designing. A DSA-formed design area restricts its pitch to one with little room for change. This poses design challenges.

Currently, fin (i.e. active layer) in the fin Field Effect Transistor (FinFET) device is being considered as one target insertion layer for DSA. However, no successful Static Random Access Memory (SRAM) design has been reported, because Fin in SRAM requires high regularity to enable the use of DSA while meeting the scaling (size).

Figure 1: Conventional FinFET SRAM: fin design style
 Fin construct in conventional FinFET SRAM has variable fin pitch.
 While logic is maintained one pitch, SRAM requires variable fin pitch.


Page 02 of 5

Figure 2: Conventional SRAM design (for reference)

Figure 3: Conventional SRAM design (for reference)

A method is needed that enables DSA into SRAM finFET design spa...