SOI Wafer Thin Film Transfer via Polymer Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for forming and transferring silicon thin films face challenges such as thermal and physical damage due to high-temperature heat treatment, inversion of device layers, and difficulties in achieving uniformity and integration, particularly in monolithic 3D technology and TSV processes.
Innovation Solution
A method involving bonding a carrier wafer with a polymer bonding material to an SOI wafer, using the buried oxide layer as an etching barrier for selective etching, and performing direct bonding at low temperatures to transfer the silicon thin film without inverting the device layer, thereby minimizing damage and improving integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature heat treatment (400°C) is performed for monolithic 3D technology, then wafer bonding and crystallization can be achieved, but copper wiring lines and already formed elements suffer thermal damage
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperature (400°C) to low temperature (200°C or below) for the heat treatment process. This parameter change enables wafer bonding and crystallization to occur at temperatures that do not cause thermal damage to copper wiring lines and already formed elements, thus resolving the contradiction between bonding reliability and thermal damage prevention
Solution Approach 2:
The patent introduces a polymer bonding material as an intermediary substance between the carrier wafer and the target wafer. This intermediary enables low-temperature bonding by providing a bonding mechanism that does not require high temperatures, thereby preventing thermal damage to sensitive components while still achieving reliable wafer bonding
2Ease of manufacture
If device layer inversion is performed in monolithic 3D technology, then lamination can be achieved, but the top and bottom of the device layer are reversed causing processing difficulties
Solution Approach 1:
Instead of inverting the device layer to achieve lamination (conventional approach), the patent inverts the approach by maintaining the correct orientation of the device layer throughout the process. The carrier wafer is bonded to the backside of the SOI wafer, and subsequent processing steps are performed without inverting the device layer, thus eliminating the complexity of re-orienting inverted layers while still achieving successful lamination
3Manufacturing precision
If additional processes are performed to improve uniformity and prevent physical damage, then film quality improves, but process complexity increases
Solution Approach 1:
The patent employs the buried oxide layer of the SOI wafer to serve multiple functions: it acts as an etching barrier during thin film formation and provides structural support during processing. This self-service approach of the buried oxide layer eliminates the need for additional protective layers or complex process steps, achieving both thin film uniformity and process simplicity
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 allows for the reliable formation and transfer of silicon thin films with reduced process complexity and improved integration, minimizing thermal and physical damage, and enabling the fabrication of semiconductor devices with enhanced three-dimensional laminated structures.
Implementation Method 1
bonding a carrier wafer coated with a polymer bonding material to a top of a silicon-on-insulator (SOI) wafer
Implementation Method 2
etching the backside silicon layer using the buried oxide layer as an etching barrier
Implementation Method 3
bonding a target wafer including an oxide layer to a bottom of the silicon layer through direct bonding
Data Source
AI summary
The present invention relates to a method of forming and transferring a thin film. The method of forming and transferring a thin film according to one embodiment may include a step of bonding a carrier wafer coated with a polymer bonding material to the top of a silicon-on-insulator (SOI) wafer formed by sequentially laminating a backside silicon layer, a buried oxide layer, and a silicon layer; a step of etching the backside silicon layer using the buried oxide layer as an etching barrier, and then selectively etching the buried oxide layer; a step of separating the carrier wafer from the polymer bonding material, and bonding a target wafer including an oxide layer to the bottom of the silicon layer through direct bonding; and a step of transferring the silicon layer to the top of the target wafer including the oxide layer by removing the polymer bonding material.