Donor Wafer Transfer via Sacrificial Layer Etching
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Solution Overview
Problem
The integration of group IV or group III-V semiconductor materials on a silicon platform is challenging due to crystalline defects such as lattice mismatch, anti-phase boundaries, and mismatch stress relaxation, and existing methods for manufacturing semiconductor devices with these materials are inefficient and prone to damage or require costly and complex processes.
Innovation Solution
A method involving a donor wafer with a sacrificial layer is used, where the sacrificial layer is formed between isolation regions, and an active layer is grown on this layer, which is then bonded to a handling wafer and lifted off, reducing the risk of damaging the active layer and allowing for the reuse of the donor wafer, thus simplifying and cost-reducing the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the donor wafer is removed by thinning or grinding from its back side, then the active layer can be transferred to the handling wafer, but the donor wafer cannot be reused and the active layer may be damaged by mechanical stress
Solution Approach 1:
A sacrificial layer is introduced as an intermediary between the donor wafer and the active layer. This sacrificial layer can be selectively removed to release the active layer from the donor wafer, enabling the donor wafer to be reused while maintaining active layer integrity. The sacrificial layer acts as a mediator that facilitates the transfer process without requiring mechanical stress on the active layer.
Solution Approach 2:
The sacrificial layer is extracted or removed selectively from the structure after the active layer has been transferred to the handling wafer. This extraction process allows the donor wafer to be released and reused, while the active layer remains intact on the handling wafer. The selective removal of the sacrificial layer resolves the contradiction between donor wafer reuse and active layer protection.
2Reliability
If the smartcut process with hydrogen implantation and annealing is used to remove the donor wafer, then the active layer can be released, but ion-induced damages and diffusion related damages occur in the active layer
Solution Approach 1:
The chemical or physical removal process of the sacrificial layer replaces the ion implantation and thermal annealing processes of the smartcut method. This substitution eliminates the harmful ion-induced damages and diffusion-related damages to the active layer, while still achieving the goal of releasing the active layer from the donor wafer. The sacrificial layer removal process is designed to be gentler and more selective than the smartcut process.
3Manufacturing precision
If existing methods are used to manufacture semiconductor devices with group IV or group III-V materials, then the active layer can be formed, but the process is complex and costly due to crystalline defects and damage risks
Solution Approach 1:
The sacrificial layer is formed in advance on the donor wafer before the active layer is grown or transferred. This preliminary action prepares the structure for easy and damage-free transfer of the active layer to the handling wafer. By having the sacrificial layer in place beforehand, the manufacturing process becomes simpler and more reliable, reducing both complexity and cost while maintaining high active layer quality.
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 method effectively reduces the risk of damaging the active layer and allows for the reuse of the donor wafer, providing a simpler, more cost-efficient process for manufacturing semiconductor devices with group IV or group III-V materials, while minimizing ion-induced and mechanical stress-related damages.
Implementation Method 1
The donor wafer may e.g. be lifted off by means of a selective etching of at least a part of the sacrificial layer
Implementation Method 2
The group III-V material is provided in fins arranged between shallow trench isolation (STI) regions in a front side of the donor wafer, and is bonded to the handling wafer by means of a bonding oxide layer.
Data Source
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AI summary
A method and a donor wafer (110) for manufacturing a semiconductor device (100) is disclosed, wherein the donor wafer is used for transferring an active layer (130), comprising a group IV, a group III-IV or a group II-VI semiconductor material, to a handling wafer (140). The method includes forming (30) the active layer on a sacrificial layer (120) of the donor wafer, bonding (40) the donor wafer to the handling wafer, and selectively etching the sacrificial layer to remove (50) the donor wafer from the handling wafer, leaving the active layer on the handling wafer. The present disclosure provides a simpler and more cost efficient process that allows for the donor wafer to be reused.