3D Circuit Assembly Using Oxygen Getter Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of 3D integrated circuits with superposed transistors faces challenges such as material degradation and bonding defects due to high thermal budgets and hydrogen degassing, particularly when using direct bonding with thin oxide layers, which can lead to untimely oxidation of the upper level semiconducting layer.
Innovation Solution
Incorporating oxygen getter materials like Ti, unhydrogenated Si, or Mo on the connection elements and areas of the transistors, which oxidize to form stable oxides, enhancing the bonding interface and preventing hydrogen degassing, thereby reducing thermal budget requirements and minimizing bonding defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If direct bonding with thin oxide layers is used, then bonding strength is improved, but hydrogen degassing causes bonding defects
Solution Approach 1:
An oxygen getter layer is introduced as an intermediary between the thin oxide bonding layer and the semiconductor substrate. This getter layer absorbs hydrogen degas during bonding, preventing hydrogen from reaching the bonding interface and causing defects, while allowing the thin oxide layer to maintain strong bonding
Solution Approach 2:
The harmful hydrogen gas is extracted from the system by the oxygen getter material, which captures and removes hydrogen atoms that would otherwise accumulate at the bonding interface and create defects during the bonding process
2Reliability
If high temperature heat treatment is applied, then bonding is achieved, but material degradation and contact deterioration occur
Solution Approach 1:
The bonding process parameters are changed by introducing the oxygen getter layer, which enables bonding at lower temperatures (below 550°C) by preventing hydrogen degassing. This temperature reduction preserves material integrity while achieving reliable bonding
3Stability of the object's composition
If thermal budget is reduced, then material degradation is prevented, but hydrogen degassing causes bonding defects
Solution Approach 1:
The oxygen getter acts as a mediator that decouples the relationship between thermal budget and bonding quality. It allows low-temperature bonding (preserving material stability) while simultaneously preventing hydrogen degassing defects through hydrogen absorption
4Manufacturing precision
If thin oxide layers are used for bonding, then bonding precision is improved, but untimely oxidation of upper level semiconducting layer occurs
Solution Approach 1:
The oxygen getter layer serves as a protective intermediary that controls oxygen availability. It prevents oxygen from reaching the upper level semiconducting layer (preventing untimely oxidation) while still enabling precise bonding through the thin oxide layer at the bonding interface
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 a stronger, defect-free bonding interface, preventing material deterioration and hydrogen-induced defects, while allowing for reduced thermal processing temperatures and maintaining the integrity of the transistors, thus improving the reliability and performance of 3D integrated circuits.
Implementation Method 1
one or several areas made of a given oxygen getter material capable of oxidising
Implementation Method 2
a hydrogen degassing phenomenon can occur and generate bonding defects
Implementation Method 3
the assembly of said structure and the support being made by bonding in which the thin silicon oxide layer is bonded to oxidised portions of said one or several areas of said given oxygen getter material
Data Source
AI summary
Fabrication of a circuit with superposed transistors includes assembly of a structure having transistors formed from a first semiconducting layer with a support provided with a second semiconducting layer in which transistors are provided on a higher level. The second semiconducting layer is coated with a thin layer of silicon oxide. The assembly of said structure and the support is made by direct bonding in which the thin silicon oxide layer is bonded to oxidised portions of getter material.