Semiconductor Substrate Diffusion via Silanol-Coated Thin Film

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Solution Overview

Problem

Existing methods for diffusing impurity ingredients into semiconductor substrates with three-dimensional nano-scale structures face challenges such as defect formation, non-uniform ion implantation, and overhang issues, leading to performance deterioration and crystal damage in CMOS image sensors and multigate elements.

Innovation Solution

A method involving a diffusion agent composition with an impurity diffusion ingredient and a Si compound hydrolyzable to produce a silanol group, applied as a thin coating film of not more than 30 nm under low relative humidity, allowing uniform diffusion into semiconductor substrates, including inner surfaces of microvoids, while minimizing defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ion implantation is used to diffuse impurity ingredients into semiconductor substrates, then diffusion efficiency is improved, but point defects and point defect clusters are formed near the surface, deteriorating element performance

Engineering Contradiction:
Improvediffusion efficiencyVSAvoidelement performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces the mechanical ion implantation process with a chemical diffusion process using a diffusion agent composition. Instead of physically implanting ions that cause damage, the invention uses a coating film containing impurity diffusion ingredients that diffuse into the substrate through thermal energy, eliminating mechanical impact damage while maintaining diffusion efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the diffusion mechanism from high-energy ion implantation to low-energy thermal diffusion. By controlling parameters such as coating film thickness (5-30 nm), heating temperature (700-1100°C), and atmosphere composition, the invention achieves effective impurity diffusion without forming point defects or clusters that deteriorate device performance.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If ion implantation is used on semiconductor substrates with three-dimensional nano-scale structures, then impurity diffusion is achieved, but uniform implantation into side surfaces and inner surfaces of concaves is difficult

Engineering Contradiction:
Improveimpurity diffusion uniformityVSAvoidion implantation uniformity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces directional ion implantation with isotropic thermal diffusion. The diffusion agent composition is coated as a thin film that conforms to three-dimensional surfaces, and thermal diffusion occurs uniformly in all directions, enabling impurity diffusion into side surfaces and inner surfaces of nanoscale concaves that are inaccessible to directional ion beams.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses a flexible thin film coating (5-30 nm thick) that can conform to complex three-dimensional nano-scale structures. This thin film encapsulates the impurity diffusion ingredients and allows them to diffuse uniformly onto all surfaces including vertical sidewalls and bottom surfaces of fins and trenches, achieving complete coverage that ion implantation cannot provide.

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If CVD method is used to form oxide film with impurity diffusion ingredients, then impurity diffusion is achieved, but overhang phenomenon causes non-uniform thickness and blocks openings of concaves

Engineering Contradiction:
Improveoxide film uniformityVSAvoidopenings coverage
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces CVD oxide film formation with direct coating of diffusion agent composition. Instead of depositing oxide that suffers from overhang effects, the invention coats a thin organic-inorganic hybrid film containing impurity diffusion ingredients that can conformally cover three-dimensional structures without blocking openings, enabling subsequent uniform thermal diffusion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 well-distributed impurity diffusion into semiconductor substrates with three-dimensional nano-scale structures, reducing defect occurrence and enhancing the performance of CMOS image sensors and multigate elements by ensuring uniform coverage and suppressing surface damage.

Implementation Method 1

a Si compound (B) that is hydrolyzable to produce a silanol group

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

diffusing the impurity diffusion ingredient (A) in the diffusion agent composition into the semiconductor substrate I

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentUS9831086B2Method for manufacturing semiconductor substrate
Publication Date: 2017.11.28 TOKYO OHKA KOGYO CO LTD

AI summary

A method for manufacturing a semiconductor substrate that, even when a substrate which has, on a surface thereof, a three-dimensional structure having nanometer-scale microvoids on a surface thereof is used, can allow an impurity diffusion ingredient to be uniformly diffused into the substrate at the whole area thereof where the diffusion agent composition is coated, including the whole inner surfaces of the microvoids, while suppressing the occurrence of defects in the substrate. A coating film having a thickness of not more than 30 nm is formed on a surface of a substrate under such conditions that an atmosphere around the substrate has a relative humidity of not more than 40%, using a diffusion agent composition comprising an impurity diffusion ingredient and a Si compound that is hydrolyzable to produce a silanol group.