Bonded Wafer Oxygen Ion Layer Removal via Oxidizing and HF Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for producing bonded wafers face challenges in achieving uniform thickness and complete removal of oxygen ion implanted layers, particularly when these layers are partially mixed with Si or SiOx, leading to defects and poor thickness distribution.
Innovation Solution
A method involving the direct bonding of wafers with oxygen ion implantation, followed by repetitive treatment with oxidizing solutions like ozone water and HF to effectively remove the oxygen ion implanted layer, improving thickness distribution and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen ion implantation is used to form an oxygen ion implanted layer, then it is possible to create a buried oxide film, but the layer becomes partially mixed with Si or SiOx and cannot be completely removed by conventional HF solution
Solution Approach 1:
The patent changes the chemical parameters of the removal solution by combining oxidizing solution (to convert Si/SiOx to SiO2) with HF solution (to dissolve SiO2). This parameter change enables complete removal of the oxygen ion implanted layer while maintaining its quality as a buried oxide film.
Solution Approach 2:
The patent uses a composite removal system consisting of oxidizing solution and HF solution working in sequence. The oxidizing solution component converts the mixed Si/SiOx layer into removable SiO2, while the HF solution component dissolves the oxidized layer, creating an effective composite removal mechanism.
2Productivity
If grinding and polishing is used to thin the wafer, then the active layer can be formed, but the thickness uniformity of the SOI layer deteriorates
Solution Approach 1:
The patent performs oxygen ion implantation and heat treatment to create a distinct buried oxide film structure before the grinding and polishing steps. This preliminary action establishes a defined interface that guides the subsequent thinning process, helping to maintain better thickness uniformity in the active layer.
Solution Approach 2:
The patent replaces purely mechanical grinding and polishing with a combined chemical-physical approach. The oxygen ion implantation and heat treatment create a chemically distinct buried oxide layer that facilitates more controlled and uniform mechanical removal during thinning, improving thickness uniformity.
3Reliability
If SIMOX method is used to produce bonded wafer, then buried oxide film can be formed, but different crystal orientations cannot be produced through the insulating layer
Solution Approach 1:
The patent segments the wafer structure into distinct layers: the active layer with its original crystal orientation, the oxygen ion implanted layer forming the buried oxide, and the support substrate. This segmentation allows each layer to have different properties and orientations independently, enabling versatility in crystal orientation while maintaining buried oxide quality.
Solution Approach 2:
The patent applies local quality by allowing different regions of the bonded wafer to have different crystal orientations. The active layer can maintain its original orientation while the support substrate can have a different orientation, and the buried oxide layer acts as an interface that accommodates this local variation.
4Productivity
If grinding-polishing method is used to produce bonded wafer, then active layer can be formed, but the thickness uniformity of the active layer is poor
Solution Approach 1:
The patent performs oxygen ion implantation and heat treatment to create a distinct buried oxide film structure before the grinding and polishing steps. This preliminary action establishes a defined interface that guides the subsequent thinning process, helping to maintain better thickness uniformity in the active layer.
Solution Approach 2:
The patent replaces purely mechanical grinding and polishing with a combined chemical-physical approach. The oxygen ion implantation and heat treatment create a chemically distinct buried oxide layer that facilitates more controlled and uniform mechanical removal during thinning, improving thickness uniformity.
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 effective removal of oxygen ion implanted layers and improves the in-plane thickness uniformity of the SOI layer, reducing defects and enhancing the quality of the final product.
Implementation Method 1
a step of implanting oxygen ions into the wafer for active layer to form an oxygen ion implanted layer in the active layer
Implementation Method 2
a step of oxidizing the bonded wafer to form an oxide film on the exposed surface of the oxygen ion implanted layer
Implementation Method 3
a step of removing the oxide film
Data Source
AI summary
Even if an oxygen ion implanted layer in a wafer for active layer is not a completely continuous SiO2 layer but a layer mixed partially with Si or SiOx, it is removed by here is provided a method for producing a bonded wafer in which it is possible to remove an oxygen ion implanted layer effectively as it is by repetitive treatment with an oxidizing solution and HF solution at a step of removing the oxygen ion implanted layer in a bonded wafer.