Wafer Debonding via Oxide Fusion Bonding and Implantation Split
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Solution Overview
Problem
Current temporary bonding techniques for wafers face challenges such as incompatibility between polymer adhesives and semiconductor materials, leading to defects, voids, and uncontrollable uniformity, along with complex and costly detaching processes.
Innovation Solution
A method involving plasma-assisted fusion bonding of silicon carrier wafers with thermal oxide, ion-implanting hydrogen near the surface, and using dangling bonds for low-temperature attachment, followed by annealing to create a planar implantation zone for easy separation, eliminating the need for external adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polymer adhesive is used for temporary bonding, then bonding can be achieved, but interface compatibility defects and voids occur due to incompatibility with semiconductor material
Solution Approach 1:
The patent removes the polymer adhesive layer entirely from the bonding interface. Instead, it uses direct bonding between the carrier wafer and device wafer through oxide layers, eliminating the source of interface compatibility defects and voids while maintaining bonding strength through oxide-oxide adhesion.
Solution Approach 2:
The patent changes the bonding mechanism from polymer-adhesive-based to oxide-layer-based bonding. By using thermal oxide layers on both carrier and device wafers, the bonding interface transitions from an incompatible polymer-semiconductor interface to a compatible oxide-oxide interface, improving reliability while maintaining strength.
2Strength
If polymer adhesive is used for temporary bonding, then bonding can be achieved, but uniformity becomes uncontrollable
Solution Approach 1:
The patent eliminates the polymer adhesive layer that causes uniformity control issues. The direct oxide-to-oxide bonding provides consistent and controllable bonding characteristics without the variability inherent in polymer coating processes.
Solution Approach 2:
The bonding process transitions from polymer-based to oxide-based, where the oxide layer thickness and properties can be precisely controlled through thermal oxidation parameters, enabling better uniformity control in the bonding process.
3Strength
If temporary bonding with adhesive is used, then mechanical support can be provided, but detaching process becomes complex and costly
Solution Approach 1:
The patent removes the adhesive layer that complicates the detaching process. The direct oxide-to-oxide bonding allows for simpler separation methods, such as mechanical cleavage or thermal release, eliminating the need for complex chemical or mechanical adhesive removal processes.
Solution Approach 2:
The patent incorporates a release structure or interface design during the bonding process that enables easy subsequent separation. This preliminary design of the bonding interface facilitates simple detaching operations after the bonding has provided the necessary mechanical support.
4Strength
If thick oxide layer is used for bonding, then bonding strength is improved, but separation at planar implantation zone becomes difficult
Solution Approach 1:
The patent creates a localized planar implantation zone within the oxide layer that has different properties from the bulk oxide. This localized modification provides a preferred separation plane, enabling easy separation at a specific location while maintaining strong bonding elsewhere.
Solution Approach 2:
The planar implantation zone is created in advance during the bonding process preparation. This preliminary creation of a separation plane allows for easy subsequent separation without requiring thick oxide removal or complex separation procedures.
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
Provides a uniform, defect-free interface with improved mechanical support and simplified bonding/de-bonding, ensuring high uniformity and reducing processing complexity and costs.
Implementation Method 1
The final device precursor is annealed to structurally weaken the carrier wafer along the planar implantation zone
Implementation Method 2
The carrier wafer is implanted with an implant material to form the planar implantation zone. The implant material may comprise hydrogen
Implementation Method 3
plasma-assisted fusion bonding of silicon carrier wafers with thermal oxide, ion-implanting hydrogen near the surface, and using dangling bonds for low-temperature attachment
Data Source
AI summary
A method for debonding carrier and device wafer assemblies comprises the following steps. A carrier wafer assembly is provided having a carrier wafer and a carrier oxide layer over the carrier wafer, wherein the carrier wafer comprises a planar implantation zone below the carrier oxide layer. A device wafer assembly is provided having a handle wafer, a device layer on the handle wafer, and a device oxide layer on the device layer. The device layer has at least one semiconductor device formed therein. The carrier wafer assembly is bonded to the device wafer assembly such that the carrier oxide layer is bonded to the device oxide layer to form a final device precursor. The final device precursor is annealed to structurally weaken the carrier wafer along the planar implantation zone. The carrier wafer assembly is separated from the final device precursor at the planar implantation zone.