SOT-MTJ Layout Pattern With Dummy MTJs for Uniform Etching

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Solution Overview

Problem

The uneven thickness and spacing of SOT-MTJ structures during the etching process lead to quality issues in the manufacturing of semiconductor structures, particularly due to the inclusion of two contact plug structures, resulting in non-uniform pattern density and process defects.

Innovation Solution

Incorporating dummy MTJ structures with varying shapes between the MTJ structures to adjust the spacing and create a more uniform pattern density, ensuring consistent etching parameters by maintaining consistent groove depths for the bottom anti-reflection layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If SOT-MTJ structures are arranged with two contact plug structures below each layer, then the device functionality is improved, but the pattern density uniformity deteriorates due to uneven spacing in different directions

Engineering Contradiction:

Improvedevice functionalityVSAvoidpattern density uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Dummy MTJ structures are introduced as intermediary elements between the actual SOT-MTJ structures. These dummy structures do not perform functional operations but serve to fill spacing gaps and uniformize the pattern density distribution across the chip, thereby resolving the contradiction between maintaining device functionality and achieving uniform pattern density for etching process control

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If SOT-MTJ structures are arranged closely in one direction to increase density, then the chip area is reduced, but the etching thickness uniformity deteriorates due to uneven groove depths

Engineering Contradiction:

Improvechip areaVSAvoidetching thickness uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The dummy MTJ structures are strategically placed in specific locations where spacing is excessive, creating a non-uniform distribution pattern that locally compensates for the uneven spacing. This local adjustment ensures that the groove depths between adjacent structures (both real and dummy) become more uniform, thereby improving etching thickness uniformity while maintaining high overall density

Inventive Principle:

Principle #3Local quality

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

The addition of dummy MTJ structures improves the uniformity of pattern density and enhances the quality of the manufacturing process by stabilizing etching parameters, reducing defects, and ensuring consistent thickness across the semiconductor structure.

Implementation Method 1

The invention relates to the field of semiconductor manufacturing, in particular to a layout pattern of a semiconductor structure with SOT-MTJ (magnetic tunneling junction using spin orbit torque technology)

Methodology Applied

Scientific EffectSpin-orbit torque:

Implementation Method 2

Spin-transfer torque (STT) is one of the techniques used to control the direction of magnetic moment in magnetic materials in the field of spintronics. The core principle of STT technology is to use spin-polarized current. When a spin-polarized current passes through a magnetic material, electrons in the current will transfer their spin angular momentum to the magnetic moment of the material, thus changing the direction of the magnetic moment.

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 3

It is known that the magnetoresistance (MR) effect is the effect that the resistance of a material changes with the change of an external magnetic field. At present, magnetoresistance effect has been successfully applied to hard disk production

Methodology Applied

Scientific EffectMagnetoresistance effect: Magnetoresistance

Implementation Method 4

This will lead to the problem of uneven thickness in the etching step and affect the process quality

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS20260033247A1Layout pattern of semiconductor structure and forming method thereof

Publication Date: 2026.01.29 UNITED MICROELECTRONICS CORP

AI summary

The invention provides a layout pattern of a semiconductor structure, which comprises a plurality of SOT (spin-orbit torque) layers arranged in an array and located on a dielectric layer, wherein two contact plug structures are connected below each SOT layer, and a plurality of MTJ (magnetic tunnel junction) structures are arranged in an array, each MTJ structure is located on each SOT layer, wherein each SOT layer comprises one MTJ structure disposed thereon. And a plurality of dummy MTJ structures located between the MTJ structures, wherein the shape of each dummy MTJ structure is different from the shape of each MTJ structure.