FinFET Gate Cut Features for Self-Aligned Gate Isolation
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Solution Overview
Problem
The challenge in semiconductor integrated circuit manufacturing lies in achieving precise and uniform cutting of gate electrodes in FinFETs, particularly in reducing alignment errors and spacing between fins, which affects yield and circuit area.
Innovation Solution
A self-aligned process is employed to form insulating cut features between device fins using a spacer material, ensuring accurate alignment and reduced spacing, and subsequent etching techniques are used to create electrically isolated gates with precise cut features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional gate cutting processes are used to electrically isolate gates, then gate isolation is achieved, but alignment errors increase and spacing between fins must be larger
Solution Approach 1:
The patent applies preliminary action by forming a spacer material around the fins before the gate cutting process. This spacer material pre-defines the precise location where cuts will be made, ensuring accurate alignment and reducing the spacing needed between fins. The spacer is deposited and patterned in advance, creating a template that guides subsequent etching operations.
Solution Approach 2:
The patent introduces an intermediary element - the spacer material - that mediates between the fin structure and the gate cutting process. This spacer acts as a physical guide and reference structure that enables precise alignment of cut features without requiring large spacing between fins. The intermediary spacer transfers the positioning information from the fin layout to the gate structure.
2Reliability
If gate cutting is performed to isolate adjacent gates, then electrical isolation is achieved, but yield decreases due to alignment errors
Solution Approach 1:
The spacer material serves as an intermediary that ensures reliable electrical isolation while maintaining high manufacturing yield. By providing a physical reference structure, the spacer eliminates alignment errors that would otherwise cause cutting failures. The intermediary spacer guarantees that cuts are made at the correct locations, ensuring both electrical isolation and process reliability.
Solution Approach 2:
The spacer material enables self-service by allowing the structure itself to define the cut locations. The spacer is formed from the same material layers as the surrounding structure, and its removal after cutting leaves clean isolation regions. The process uses the existing fin and spacer structures to automatically determine where cuts should be made, reducing dependency on external alignment references.
3Area of stationary object
If precise alignment is achieved through improved cutting processes, then circuit area is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent reduces manufacturing complexity by performing preliminary actions - forming the spacer material and pattern - before the actual gate cutting. This preliminary structure serves as a permanent reference that simplifies subsequent cutting operations. Instead of requiring complex real-time alignment systems, the preliminary spacer provides a static guide that reduces the complexity of the cutting process itself.
Solution Approach 2:
The intermediary spacer material acts as a bridge between the simple fin formation process and the complex gate isolation requirement. By introducing this intermediate structure, the patent transforms a potentially complex alignment problem into a simpler process where cuts are made relative to the spacer. This intermediary element manages the complexity by providing a clear reference framework.
Data Source
AI summary
Examples of an integrated circuit with gate cut features and a method for forming the integrated circuit are provided herein. In some examples, a workpiece is received that includes a substrate and a plurality of fins extending from the substrate. A first layer is formed on a side surface of each of the plurality of fins such that a trench bounded by the first layer extends between the plurality of fins. A cut feature is formed in the trench. A first gate structure is formed on a first fin of the plurality of fins, and a second gate structure is formed on a second fin of the plurality of fins such that the cut feature is disposed between the first gate structure and the second gate structure.