Thin Silicon Layer Transfer by Ion-Implanted Cleavage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for transferring thin silicon layers from a donor substrate to a handle substrate in silicon-on-insulator (SOI) structure fabrication are time-consuming, costly, and lack suitable thickness uniformity for layers thinner than a few microns.
Innovation Solution
A method involving the implantation of H2+ and He+ ions into the donor substrate, followed by annealing to form a damage layer, bonding to a handle substrate, and subsequent cleaving at the damage layer to transfer a silicon layer with a thickness between 500 Angstroms and 2500 Angstroms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wafer bonding and back etching methods are used to transfer silicon layers, then layer transfer can be achieved, but the process is time-consuming and costly
Solution Approach 1:
The patent applies preliminary action by implanting hydrogen ions into the donor wafer before bonding occurs. This pre-creates a cleavage plane at the desired depth, so that when the wafer is subsequently bonded and processed, the thin layer can be easily separated along this pre-formed plane. This eliminates the need for time-consuming back etching processes while maintaining precise thickness control.
2Productivity
If conventional back etching is used to remove donor wafer material, then layer transfer is achieved, but substantial substrate is wasted
Solution Approach 1:
The patent extracts only the necessary thin layer (500-2500 Angstroms) from the donor wafer by utilizing the pre-formed hydrogen implantation cleavage plane. Instead of removing substantial portions of the donor wafer through back etching, the method selectively separates and transfers only the required thin silicon layer to the handle wafer, leaving the bulk of the donor substrate intact for potential reuse.
3Strength
If thermal annealing is used to strengthen wafer bonds, then bond strength is improved, but process complexity and cost increase
Solution Approach 1:
The patent utilizes parameter changes by controlling the depth and dose of hydrogen ion implantation to create a cleavage plane at the precise depth where the thin layer will be transferred. By adjusting implantation energy and dose parameters, the method achieves both strong bonding and controlled layer separation without requiring complex multi-step thermal processing sequences.
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 enables the efficient transfer of thin silicon layers with improved thickness uniformity, reducing manufacturing costs and time, while allowing for the recycling of the donor wafer.
Implementation Method 1
implanting H2+ ions, H+ ions, or a combination of H2+ ions and H+ ions through a silicon dioxide layer in contact with a front surface of the single crystal silicon donor substrate and through the front surface of the single crystal silicon donor substrate
Implementation Method 2
implanting He+ ions through the silicon dioxide layer in contact with the front surface of a single crystal silicon donor substrate and through the front surface of the single crystal silicon donor substrate
Implementation Method 3
annealing the ion implanted single crystal silicon donor substrate at a temperature and for a duration sufficient to form a damage layer in the single crystal silicon donor substrate
Implementation Method 4
bonding the silicon dioxide layer in contact with the front surface of the single crystal silicon donor substrate to a dielectric layer in contact with the handle substrate
Implementation Method 5
cleaving the annealed multilayer substrate at the damage layer in the single crystal silicon donor substrate to thereby transfer the silicon layer
Data Source
AI summary
A method for preparing semiconductor on insulator structures comprises transferring a thin layer of silicon from a donor substrate onto a handle substrate.