SiC Wafer Splitting via Separation Region and Controlled Cracking
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Solution Overview
Problem
The integration of SiC wafer splitting into the standard SiC production process is complex and requires modifications, leading to inefficiencies and increased costs, necessitating an efficient and cost-sensitive integration of SiC wafer splitting and production processes.
Innovation Solution
A method involving the formation of a separation region with altered physical properties to increase thermo-mechanical stress, followed by applying an external force or laser radiation to propagate cracks, allowing the semiconductor wafer to split into two pieces, one retaining device structures, while using a carrier to stabilize the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SiC wafer splitting is integrated into standard SiC production process, then material utilization efficiency is improved, but process complexity increases
Solution Approach 1:
The patent applies preliminary action by forming a separation region within the SiC wafer before the splitting operation. This separation region is created through ion implantation or laser irradiation, which modifies the physical properties of the wafer at the intended split location. By preparing this separation region in advance, the subsequent splitting process becomes more controlled and efficient, allowing the wafer to be divided cleanly into a device wafer and a reclaimed wafer that can be reused for additional device structures, thereby improving material utilization without excessive process complexity
Solution Approach 2:
The patent applies segmentation by dividing the SiC wafer into two distinct parts: a device wafer containing the formed device structures and a reclaimed wafer that can be reused. This segmentation is achieved through controlled cracking along the pre-formed separation region. The reclaimed wafer portion is then reused to form additional device structures, effectively multiplying the utility of the original SiC material and improving overall material utilization efficiency
2Manufacturing precision
If external force is applied to propagate cracks along separation region, then wafer splitting precision is improved, but risk of damaging device structures increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a separation region with altered physical properties as a mediator between the external force and the wafer splitting process. This separation region, formed through ion implantation or laser irradiation, creates a controlled path of reduced strength within the wafer. When external force is applied, cracks propagate preferentially along this pre-defined separation region rather than randomly through the wafer, ensuring precise splitting while protecting the device structures from damage
Solution Approach 2:
The patent applies parameter changes by modifying the physical properties of the separation region through ion implantation or laser irradiation. These parameter changes create a region with different mechanical strength and crack propagation characteristics compared to the surrounding wafer material. By controlling parameters such as ion dose, energy, or laser power, the separation region is engineered to guide crack propagation precisely along the desired path, achieving high splitting precision while maintaining device structure integrity
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 approach reduces material waste, minimizes unwanted surface structures, and enhances reproducibility, thereby lowering manufacturing costs and improving the efficiency of SiC semiconductor device production.
Implementation Method 1
forming a separation region within the semiconductor wafer, the separation region having at least one altered physical property which increases thermo-mechanical stress within the separation region relative to the remainder of the semiconductor wafer
Implementation Method 2
applying laser radiation to a separation region within the semiconductor wafer such that the separation region increased thermo-mechanical stress relative to the remainder of the semiconductor wafer
Implementation Method 3
applying an external force to the semiconductor wafer such that at least one crack propagates along the separation region and the semiconductor wafer splits into two separate pieces
Data Source
AI summary
A method of splitting a semiconductor wafer includes: forming a slot in an edge of the semiconductor wafer; applying a first stressor to the semiconductor wafer; and applying a second stressor different than the first stressor to the semiconductor wafer, such that the semiconductor wafer splits into two separate pieces. A front side of the semiconductor wafer includes at least one of: a plurality of device structures of a semiconductor device; a metallization layer; and a passivation layer.