Alignment Mark Detection in Block Copolymer Self-Assembly

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Solution Overview

Problem

The formation of alignment marks using conventional methods in semiconductor manufacturing results in unexpected microstructures due to self-assembly of block copolymers, making it difficult to detect these marks and potentially reducing overlay precision between substrate layers.

Innovation Solution

A method involving exposing a substrate to a mask image to form first and second marks, applying a polymer layer containing a block copolymer, forming self-assembled regions, selectively removing portions, and creating first and second positioning marks with different shapes to facilitate accurate detection and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If alignment marks are formed using conventional methods in a substrate that undergoes block copolymer self-assembly, then the block copolymer forms unexpected microstructures within the alignment marks, but this makes the alignment marks difficult to detect and reduces overlay precision

Engineering Contradiction:

Improvealignment mark formation precisionVSAvoidalignment mark detection precision

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The alignment mark structure is segmented into multiple components: a base alignment mark and additional distinctive microstructures. This segmentation allows the mark to serve dual purposes - maintaining detectability through the base structure while providing unique identification through additional features that prevent confusion with circuit patterns

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Additional asymmetric microstructures are formed adjacent to or integrated with the conventional alignment mark. These asymmetric features create an unique signature that distinguishes the alignment mark from the symmetric or regularly patterned circuit patterns, enabling reliable detection even when block copolymer self-assembly occurs

Inventive Principle:

Principle #4Asymmetry

2Manufacturing precision

If block copolymer self-assembly is used to form nanoscale circuit patterns, then sub-lithographic structures can be achieved, but alignment marks formed in the same layer become indistinguishable due to unexpected microstructure formation

Engineering Contradiction:

Improvecircuit pattern resolutionVSAvoidalignment mark detectability

Core Design Contradiction:

Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The alignment mark structure is designed in advance to include distinctive features that will remain detectable even after block copolymer self-assembly. The mark formation process incorporates preliminary structuring that ensures detectability is maintained throughout subsequent processing steps

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Different regions of the alignment mark structure are given different qualities - the base structure maintains conventional characteristics for detection, while additional regions incorporate unique microstructures that provide identification. This local differentiation ensures both detectability and distinguishability

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional alignment mark formation is performed before block copolymer application, then the alignment marks are formed simply, but the subsequent block copolymer self-assembly creates harmful microstructures within the marks

Engineering Contradiction:

Improvealignment mark formation simplicityVSAvoidunexpected microstructure formation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The alignment mark structure is designed with preliminary protective features that prevent harmful block copolymer microstructures from forming within the critical detection regions. The structure includes zones that are either protected from self-assembly or designed to channel it into non-interfering patterns

Inventive Principle:

Principle #9Preliminary anti-action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the formation of precise positioning marks that can be effectively detected and used for high-precision alignment, overcoming the challenges of microstructure formation and improving overlay precision in semiconductor device manufacturing.

Implementation Method 1

forming self-assembled regions in at least a portion of the applied polymer layer

Methodology Applied

Scientific EffectSelf-assembly: Self-Assembly

Implementation Method 2

exposing a region, of a substrate, including a mark formation region with a mask image to form a first mark and a second mark

Methodology Applied

Scientific EffectPhoto-lithography: Photopolymerisation

Data Source

PatentUS10354959B2Mark forming method, mark detecting method, and device manufacturing method using self-assembled block copolymer

Publication Date: 2019.07.16 NIKON CORP

AI summary

A mark forming method includes: exposing a wafer with a mask image to form first and second resist marks that have different shapes than one another based on a portion of the mask image; applying a polymer layer that contains a block copolymer to the wafer by spin-coating; forming self-assembled regions in the applied polymer layer; selectively removing a portion of the self-assembled regions; and forming first and second wafer marks on the wafer using the first and second resist marks. This makes it possible to form the marks when forming circuit patterns using self-assembly of a block copolymer.