Selective Metal Deposition for Microelectronic Device Manufacturing

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Solution Overview

Problem

Current methods for manufacturing microelectronic devices face challenges such as high metal consumption, non-uniform metal layer deposition, especially in complex structures, and the inability to deposit different metal layers on various semiconductor substrates, leading to inconsistent contact layer performance.

Innovation Solution

A method involving the formation of semiconductor layers on distinct zones of a substrate, followed by selective deposition of metal layers using electrochemical means, allowing for the creation of identical or different intermetallic compounds or solid solutions, with sacrificial layers to optimize metal layer thickness and uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If physical vapor deposition (PVD) is used to deposit metal layer on the entire surface, then metal layer can be formed on all zones, but metal consumption is high and deposition uniformity is poor

Engineering Contradiction:
Improvedeposition uniformityVSAvoidmetal consumption
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent applies local quality by making the metal deposition selective to specific zones based on semiconductor material type. Different metal layers are deposited only where needed (on p-type or n-type semiconductor zones) rather than uniformly across the entire substrate, thereby reducing metal consumption while maintaining deposition uniformity in the targeted areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses preliminary action by forming sacrificial oxide layers on semiconductor zones before metal deposition. These sacrificial layers are created through selective oxidation, which prepares the surface and enables subsequent selective metal deposition. The sacrificial layers are later removed to reveal the underlying semiconductor zones, achieving the desired metal layer distribution without wasting metal on non-reactive areas.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If PVD process is used for metal deposition, then metal layer can be formed, but deposition uniformity in complex structures with high aspect ratio is difficult to achieve

Engineering Contradiction:
Improvedeposition uniformity in complex structuresVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical PVD deposition system with a chemical deposition system. Instead of physically depositing metal vapor, the process uses chemical reactions where metal ions in solution are reduced and deposited onto the semiconductor surface. This chemical approach allows better penetration into complex structures with high aspect ratios, achieving uniform deposition in locations where mechanical PVD would fail due to shadowing effects.

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

3Adaptability or versatility

If conventional PVD deposition is used, then metal layer can be deposited, but different metals cannot be deposited on different contact recovery zones without masking

Engineering Contradiction:
Improvemetal layer differentiationVSAvoidprocess complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating distinct chemical environments in different zones of the substrate. By controlling the oxidation conditions and using different sacrificial layer materials (silicon oxide for p-type, silicon nitride for n-type), the process enables different metal layers to be selectively deposited in different zones without requiring physical masks. Each zone's chemical properties dictate which metal will deposit, providing inherent spatial selectivity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses sacrificial oxide layers as intermediaries to enable selective metal deposition. These intermediate layers are formed through selective oxidation of semiconductor zones and serve as templates that guide subsequent metal deposition. The intermediaries are later removed to reveal the final metal layer pattern, allowing different metals to be deposited on different zones through chemical rather than mechanical means.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Loss of substance

If electroless deposition is used to deposit metal layer, then metal consumption is reduced, but uniform deposition on substrates with different materials is difficult to achieve

Engineering Contradiction:
Improvemetal consumptionVSAvoiddeposition uniformity on different substrates
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent applies local quality by tailoring the electroless deposition conditions to each substrate type. Different metal layers are deposited selectively on p-type or n-type semiconductor zones based on their specific material properties. The deposition parameters (such as solution composition, temperature, and pH) are optimized for each zone's characteristics, ensuring uniform deposition on each substrate type while maintaining overall process efficiency and low metal consumption.

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

This approach reduces metal waste, enhances the uniformity and flexibility of metal layer deposition, enabling better performance and conductivity for both p-type and n-type transistors by standardizing metal layers on diverse semiconductor materials.

Implementation Method 1

a first metal layer is formed in a first zone by an electrochemical deposition process; a second metal layer is formed in a second zone by an electrochemical deposition process

Methodology Applied
Scientific EffectElectrochemical deposition: Electrodeposition

Implementation Method 2

under the effect of heat treatment, the metal layer reacts preferentially with semiconductor zones rather than with dielectric zones

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

a first sacrificial layer is formed by oxidation of a first metal layer, and a second sacrificial layer is formed by oxidation of a second semiconductor layer

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP2894665B1Method for manufacturing a microelectronic device
Publication Date: 2020.10.28 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2894665B1 patent drawingFigure 1a
  • EP2894665B1 patent drawingFigure 1b
  • EP2894665B1 patent drawingFigure 2a~2c

AI summary

The invention relates to a method for manufacturing a microelectronic device comprising, on the basis of a substrate: - the formation of a first layer (201) of a first semiconductor material, on a first area of ​​an upper surface of the substrate; - the formation of a second layer (202) of a second semiconductor material, on a second area, distinct from the first area, of the upper surface of the substrate; it comprises, after the formation of the second layer (202): - the formation of a first metallic layer above the first layer; - the formation of a first contact layer (281) of a first intermetallic compound or solid solution comprising at least a portion of the first layer and at least a portion of the first metallic layer;- the formation of a first sacrificial layer by oxidation, over a thickness e1, of an upper portion of the first contact layer, and the formation of a second sacrificial layer by oxidation, over a thickness e2, of an upper portion of the second layer; - the removal of the entire second sacrificial layer so as to expose a residual portion of the second layer and a partial removal of the first sacrificial layer; - the formation of a second metallic layer above said residual portion; - the formation of a second contact layer (282) of a second intermetallic compound or solid solution comprising at least a portion of said residual portion and at least a portion of the second metallic layer.