Silicon Carbide Wafer Splitting With Ion-Implanted Bow Mitigation
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Solution Overview
Problem
Wafer splitting from a crystalline substrate, such as silicon carbide, often results in bowing, complicating subsequent process integration steps and increasing manufacturing costs.
Innovation Solution
Implanting cleaving ions at a first depth from one surface and non-cleaving ions at a second depth into the substrate to create a separation and mitigation layer, respectively, followed by thermal energy application to separate the wafer while minimizing further separation at the mitigation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafer splitting is performed to increase device yield, then more devices can be produced from a single substrate, but wafer bowing occurs which complicates subsequent process integration
Solution Approach 1:
The patent applies preliminary anti-action by implanting ions at a first depth to create compressive stress that counteracts the tensile stress-induced bowing. This pre-applied counterforce prevents the wafer from bowing during subsequent processing steps, allowing multiple wafers to be split while maintaining manufacturing precision.
Solution Approach 2:
The patent changes physical parameters by controlling ion implantation depth, dose, and energy to precisely adjust the stress state in the substrate. By varying these parameters, the process optimizes the balance between enabling wafer splitting (productivity) and maintaining wafer flatness (manufacturing precision).
2Ease of manufacture
If ion implantation is used to create separation layers, then wafer splitting becomes possible, but substrate bowing is introduced
Solution Approach 1:
The patent applies local quality by creating distinct ion implantation zones at different depths with different ion types. The first ion implantation creates a separation layer for easy wafer splitting, while the second ion implantation creates a stress compensation layer at a different location (depth) to counteract bowing, allowing each zone to serve its specific function.
Solution Approach 2:
The patent creates a composite structure within the substrate by combining different ion-implanted regions. The separation layer (first ion type) and stress compensation layer (second ion type) form a composite system where each component contributes different properties - one enables splitting while the other maintains shape stability.
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
Effectively mitigates wafer bowing, allowing for efficient production of multiple wafers from a single substrate with reduced defects and improved integration compatibility.
Implementation Method 1
implant a cleaving ionic species into a crystalline substrate to a first depth from a substrate first surface. The implantation of the cleaving ionic species may cause bowing of the crystalline substrate and/or the attached wafer.
Implementation Method 2
followed by thermal energy application to separate the wafer while minimizing further separation at the mitigation layer
Data Source
AI summary
Methods of forming a crystalline wafers such as silicon carbide wafers are disclosed. Such a method may include providing a crystalline substrate comprising a substrate first surface and a substrate second surface opposite the substrate first surface. The method may also include creating a separation layer at a first depth from the substrate first surface and creating a mitigation layer at a second depth from a substrate second surface. Creating the separation layer may cause the crystalline substrate to bow, and creating the mitigation layer may reduce the bow of the crystalline substrate. The method may further include separating the wafer from the crystalline substrate along the separation layer.