Carrier Wafer Debonding via Implanted Separation Plane
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Solution Overview
Problem
There is a need for an efficient technique to separate the device layer from the parent Si substrate in RF switch devices fabricated on silicon-on-insulator (SOI) wafers with precise control, to reduce manufacturing costs and improve device performance by allowing processing with alternative materials on the backside.
Innovation Solution
A method involving hydrogen implantation to create a planar implantation zone in the substrate, bonding with a carrier wafer using an adhesive, annealing to weaken the substrate, and separating it to form a thinned device wafer assembly, followed by removing residual substrate and debonding the carrier, with optional passivation and mold compound layers for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the device layer is separated from the parent Si substrate using conventional methods, then the separation process becomes complex and costly, but manufacturing precision and device performance can be improved
Solution Approach 1:
The patent applies preliminary action by forming the implantation zone within the substrate before bonding the device layer to the carrier wafer. This pre-positioned weak separation plane enables controlled separation later without requiring complex processing steps, thus improving separation precision while maintaining ease of manufacture
Solution Approach 2:
The patent segments the substrate by creating a planar implantation zone that acts as a predetermined separation plane. This segmentation allows the device layer to be cleanly separated from the parent substrate along a precise plane, achieving high manufacturing precision through structural division rather than complex processing
2Adaptability or versatility
If alternative materials are used on the backside of the device layer, then device performance can be improved and costs reduced, but the separation technique must be precisely controlled
Solution Approach 1:
The implantation zone is formed in advance within the substrate, creating a predetermined separation plane that enables precise control during later separation steps. This preliminary positioning of the weak plane ensures that even when separating for alternative backside materials, the separation occurs at the exact desired location with high precision
Solution Approach 2:
The patent applies local quality by creating a localized implantation zone with specific properties (hydrogen or helium ions at controlled depth and concentration) within the substrate. This localized modification creates a distinct separation plane with different properties from the rest of the substrate, enabling precise separation control while allowing versatility in backside material selection
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
Enables precise separation of the device layer from the substrate, allowing processing with alternative materials to enhance device performance and reduce costs, while maintaining semiconductor integrity.
Implementation Method 1
The substrate is annealed to weaken the substrate along the planar implantation zone
Implementation Method 2
The substrate is annealed to weaken the substrate along the planar implantation zone
Implementation Method 3
The carrier wafer assembly is bonded to the device layer of the device wafer assembly with an adhesive
Data Source
AI summary
A process for debonding carrier and device wafer assemblies comprises providing a carrier wafer assembly and a device wafer assembly that comprises a substrate, and a device layer on the substrate. The device layer has at least one semiconductor device formed therein, and the substrate has a planar implantation zone of implant material below the device layer. The carrier wafer assembly is bonding to the device layer of the device wafer assembly with an adhesive. The substrate is annealed to weaken the substrate along the planar implantation zone. A main portion of the substrate above the planar implantation zone is separated from the device wafer assembly to form a thinned device wafer assembly. A residual portion of the substrate is removed from the thinned device wafer assembly to form a precursor.