Chalcogenidometallate Molecular Solders for Semiconductor Bonding

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Solution Overview

Problem

There is a lack of established methods for joining semiconductor pieces under mild conditions without disrupting their semiconducting properties, which is essential for technologically important inorganic semiconductors.

Innovation Solution

The use of chalcogenidometallate compounds, specifically alkali metal-containing chalcogenidometallates of group IIB, IV, and V elements, as molecular solders to form structures such as thin films, molded objects, and bonded surfaces, including field effect transistors, by coating substrates with a dispersion of metal chalcogenide particles and precursors and annealing them to form metal chalcogenides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional soldering methods are used to join semiconductor pieces, then mechanical and electrical connection is achieved, but semiconducting properties at the joint are disrupted

Engineering Contradiction:

Improvejoint strengthVSAvoidsemiconducting properties

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the solder material by using chalcogenidometallate compounds with specific stoichiometries (e.g., A2MCh2, A2Cd2Se3, A4Bi2Ch5) that match the semiconductor substrate. This compositional matching enables the solder to maintain semiconducting properties while providing mechanical and electrical connection.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The chalcogenidometallate compound acts as an intermediary material between semiconductor pieces. It has intermediate properties that are compatible with both the semiconductor substrate and the joining requirements, allowing bond formation without disrupting the semiconducting properties of the joined pieces.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If high temperatures are used for joining semiconductor pieces, then mechanical bonding is achieved, but semiconducting properties are disrupted

Engineering Contradiction:

Improvebond strengthVSAvoidprocessing temperature

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The invention utilizes phase transition of the chalcogenidometallate compound during annealing, where the compound transforms from a precursor phase to a bonded semiconductor phase. This phase transition occurs at controlled temperatures that enable bonding while preserving semiconducting properties.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The invention employs composite material strategy by combining metal chalcogenide particles with chalcogenidometallate precursor compounds in a dispersion. This composite approach allows the system to achieve both bonding functionality and semiconducting properties through the synergistic interaction of components.

Inventive Principle:

Principle #40Composite materials

3Reliability

If metal chalcogenide particles and precursors are dispersed in solvent and annealed, then metal chalcogenide structures are formed with high electron mobilities

Engineering Contradiction:

Improveelectron mobilityVSAvoidfabrication process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention applies preliminary action by pre-dispersing metal chalcogenide particles and precursors in solvent to form a homogeneous coating before annealing. This preliminary dispersion ensures uniform distribution of components, which leads to high electron mobility in the final structure without requiring complex post-processing steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention replaces complex mechanical joining systems with a chemical-thermal process. Instead of mechanical assembly and bonding, the method uses chemical dispersion followed by thermal annealing to form integrated metal chalcogenide structures, simplifying the overall fabrication process while achieving high performance.

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 allows for the bonding of semiconductor pieces with minimal disruption to their semiconducting properties, achieving high electron mobilities and enabling the creation of high-performance field effect transistors with enhanced thermal and electrical conductivities.

Implementation Method 1

annealing the coating to form the structure of the metal chalcogenide

Methodology Applied

Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

annealing the coating to form the structure of the metal chalcogenide

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS10283357B2Compositionally matched molecular solders for semiconductors

Publication Date: 2019.05.07 UNIVERSITY OF CHICAGO

AI summary

Chalcogenidometallates of group IIB, IV and V elements and, particularly, alkali metal-containing chalcogenidometallates of cadmium, lead and bismuth are provided. Also provided are methods of using the chalcogenidometallates as molecular solders to form metal chalcogenide structures, including thin films, molded objects and bonded surfaces composed of metal chalcogenides.