Fin Mask for Saddle Type Fin Fabrication

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Solution Overview

Problem

The existing method for fabricating saddle type transistors forms dummy saddle type fins at the ends of active regions, leading to increased leakage and gate capacitance, which deteriorates transistor performance.

Innovation Solution

A fin mask combination is used, comprising a first line-type fin mask and a second island-type or opening-type fin mask, which selectively exposes saddle type fin regions while covering the ends of neighboring active regions, preventing the formation of dummy fins during the etching process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a line type fin mask is used to form saddle type fins, then the fin mask can be simply formed, but dummy saddle type fins are formed at the ends of active regions leading to increased leakage and gate capacitance

Engineering Contradiction:

Improvefin mask formation simplicityVSAvoidtransistor performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The fin mask is divided into two separate components: a line type fin mask for defining the basic fin pattern and a separate end mask for covering the ends of active regions. This segmentation allows each mask to perform its specific function independently, preventing dummy fin formation while maintaining the simplicity of line type mask formation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An end mask is introduced as an intermediary element that specifically covers the ends of active regions where dummy fins would otherwise form. This end mask acts as a mediator between the line type fin mask and the etching process, selectively preventing etching at critical locations without affecting the overall fin formation process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If the fin mask covers all active regions uniformly, then dummy fins are prevented, but the desired saddle type fins cannot be formed in the center regions

Engineering Contradiction:

Improvefin formation accuracyVSAvoidetching process efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The masking strategy applies different masking qualities to different regions: the line type fin mask provides uniform coverage for fin formation in center regions, while the end mask provides selective coverage only at the ends of active regions. This local differentiation allows precise control of etching to form saddle type fins in center regions while preventing dummy fins at ends.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of applying a complete uniform mask across all regions, the solution uses partial masking with the end mask applied only where needed at the active region ends. This partial action approach prevents over-masking that would block desired fin formation in center regions while still providing protection where dummy fins would form.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8377826B2Fin mask and method for fabricating saddle type fin using the same

Publication Date: 2013.02.19 SK HYNIX INC

AI summary

A fin mask for forming saddle type fins in each of active regions formed in an island shape having a certain size with a major axis and a minor axis includes a first fin mask of a line type, and a second fin mask of an island type, wherein the first fin mask and the second fin mask in combination expose saddle type fin regions and cover ends of the neighboring active regions along the major axis.