Fin Field Effect Transistor Cutting via Self-Aligned Sidewalls

Solution Overview

Problem

Existing methods for cutting off unwanted fins in fin field effect transistors require high precision lithography equipment, which is costly and often not available, especially as semiconductor process nodes shrink, making it difficult to implement with less advanced lithography equipment.

Innovation Solution

A method that involves forming a first pattern structure with wider dimensions, followed by the creation of second sidewalls for self-alignment, allowing the cutting off of fins without direct photolithography definition, reducing the need for high precision lithography equipment by using a less advanced lithography equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high precision lithography equipment is used to cut off fins, then manufacturing precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvelithography precisionVSAvoidlithography equipment complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the fin cutting process into multiple steps: first forming a pattern structure with wider dimensions that is easier to lithograph, then using etching to create sidewalls that define the final fin boundaries. This segmentation allows the lithography step to work at relaxed precision while subsequent self-aligned etching achieves the required fine precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by first forming a pattern structure with intentionally wider dimensions than the final fin spacing. This preliminary pattern serves as a template that guides subsequent self-aligned etching processes, allowing the actual fin definition to occur without direct lithography intervention at the critical dimension.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If high precision lithography equipment is used to cut off fins, then manufacturing precision is improved, but cost increases

Engineering Contradiction:

Improvelithography precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent segments the fin cutting process into multiple steps: first forming a pattern structure with wider dimensions that is easier to lithograph, then using etching to create sidewalls that define the final fin boundaries. This segmentation allows the lithography step to work at relaxed precision while subsequent self-aligned etching achieves the required fine precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by first forming a pattern structure with intentionally wider dimensions than the final fin spacing. This preliminary pattern serves as a template that guides subsequent self-aligned etching processes, allowing the actual fin definition to occur without direct lithography intervention at the critical dimension.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If advanced lithography equipment is used to cut off fins at small process nodes, then manufacturing precision is improved, but availability decreases

Engineering Contradiction:

Improvelithography precisionVSAvoidequipment availability

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent segments the fin cutting process into multiple steps: first forming a pattern structure with wider dimensions that is easier to lithograph, then using etching to create sidewalls that define the final fin boundaries. This segmentation allows the lithography step to work at relaxed precision while subsequent self-aligned etching achieves the required fine precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by first forming a pattern structure with intentionally wider dimensions than the final fin spacing. This preliminary pattern serves as a template that guides subsequent self-aligned etching processes, allowing the actual fin definition to occur without direct lithography intervention at the critical dimension.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11640910B2Method for cutting off FIN field effect transistor

Publication Date: 2023.05.02 SHANGHAI HUALI INTEGRATED CIRCUIT CORP

AI summary

A method for cutting off a fin in a field effect transistor, comprising: step 1: forming fins and first spacing regions, there are two types of fins—the first type is configured to be cut off and a second type is configured to be reserved; and forming a first material layer to fill the first spacing regions; step 2: forming a first pattern structure comprising first strip structures aligning to one first type fin and second spacing regions; step 3: forming second sidewalls on two sides of each first strip structure; step 4: removing the first strip structures to form a second pattern structure by the second sidewalls; step 5: etching away the first material layer and the first type of fins by using the second sidewalls as a mask ; step 6: removing the second sidewalls and the remaining first material layer. The present application enables using less advanced lithography equipment.