Amorphous Silicon Photolithography Surface Treatment for Pattern Accuracy

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Solution Overview

Problem

The photolithography process in semiconductor device manufacturing suffers from low accuracy in pattern transfer due to impurities on the surface of the amorphous silicon layer, leading to pattern defects and reduced quality of the semiconductor device.

Innovation Solution

A method involving the formation of a composite layer with an amorphous silicon and silicon dioxide layer, followed by dry etching and plasma surface treatment using second plasma to neutralize charges and remove impurities, improving adhesion between the amorphous silicon layer and the photoresist layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a photoresist is coated for exposure in a front-end photolithography process, then the semiconductor device manufacturing process can proceed, but the accuracy of pattern transfer is not high due to impurities on the amorphous silicon layer surface

Engineering Contradiction:
Improvepattern transfer accuracyVSAvoidimpurities on amorphous silicon layer surface
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies a preliminary plasma surface treatment to the amorphous silicon layer before photoresist coating. This treatment removes impurities and activates the surface in advance, creating an optimal surface condition for subsequent photoresist adhesion and pattern transfer, thereby resolving the contradiction between maintaining surface integrity and eliminating harmful impurities.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses plasma treatment to convert the harmful impurities on the amorphous silicon layer surface into a beneficial effect. The plasma process not only removes organic contaminants but also creates surface activation that enhances photoresist adhesion, transforming the problematic impure surface into an ideal substrate for photolithography.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

If the amorphous silicon layer surface is treated to remove impurities, then pattern transfer accuracy improves, but additional process steps are required

Engineering Contradiction:
Improvepattern transfer accuracyVSAvoidnumber of process steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the plasma surface treatment step with the existing photolithography process flow. By integrating the surface treatment into the standard process sequence and using the same plasma equipment, the additional complexity is minimized while achieving the desired pattern transfer accuracy improvement.

Inventive Principle:
Principle #5Merging (Combining)

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

Enhances the accuracy of pattern transfer by improving the adhesion between the amorphous silicon layer and the photoresist layer, thereby reducing pattern defects and enhancing the overall quality of the semiconductor device.

Implementation Method 1

performing, by using second plasma, a plasma surface treatment on an exposed part of the surface of the amorphous silicon layer

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

plasma surface treatment using second plasma to neutralize charges and remove impurities

Methodology Applied
Scientific EffectCharge neutralization: Electrostatics

Implementation Method 3

dry etching the silicon dioxide layer in the array region by using first plasma

Methodology Applied
Scientific EffectDry etching:

Implementation Method 4

dry etching the silicon dioxide layer in the array region by using first plasma, to expose a part of the surface of the amorphous silicon layer

Methodology Applied
Scientific EffectPlasma etching: Plasma

Data Source

PatentEP4020526B1Semiconductor fabrication method
Publication Date: 2024.05.22 CHANGXIN MEMORY TECH INC
  • EP4020526B1 patent drawingFigure 1
  • EP4020526B1 patent drawingFigure 2
  • EP4020526B1 patent drawingFigure 3~5

AI summary

The present disclosure provides a semiconductor device and a method of manufacturing a semiconductor device. The method of manufacturing a semiconductor device includes: providing a substrate that includes an array region and an edge region; forming a composite layer on the substrate, where the composite layer includes an amorphous silicon layer and a silicon dioxide layer, and the silicon dioxide layer is located on a surface of the amorphous silicon layer away from the substrate; dry etching the silicon dioxide layer in the array region by using first plasma, to expose a part of the surface of the amorphous silicon layer in the array region; performing, by using second plasma, a plasma surface treatment on an exposed part of the surface of the amorphous silicon layer; cleaning an amorphous silicon layer on which the plasma surface treatment has been performed and a dry etched silicon dioxide layer; and coating a first photoresist layer on the composite layer in the edge region and the array region of the substrate, and performing exposing and developing.