SiC Backside Metal Frame Structure for Thin-Wafer Separation
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Solution Overview
Problem
The handling of semiconductor wafers becomes increasingly complex with decreasing thickness, requiring auxiliary carriers for mechanical stability during processing, and existing methods for thinning and dicing are inefficient, especially for silicon carbide wafers.
Innovation Solution
A method involving a silicon carbide substrate with an idle layer and a device layer, where an auxiliary carrier is bonded to the substrate, and a mold structure is formed to separate device regions, allowing for reduced thickness and improved mechanical stability without extensive grinding, using a grid-shaped groove and frame structures for precise separation and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wafer thickness is reduced to improve device characteristics, then on-state resistance decreases, but mechanical stability deteriorates
Solution Approach 1:
A support structure is introduced as an intermediary element between the thinned semiconductor wafer and the handling system. This support structure provides mechanical stability during processing while allowing the wafer to maintain its reduced thickness for optimal electrical performance. The support structure acts as a mediator that decouples the conflicting requirements of thinness and strength.
2Length of moving object
If extensive grinding processes are used to thin wafers, then final thickness is reduced, but manufacturing complexity increases
Solution Approach 1:
The support structure is attached to the wafer before the thinning process begins. This preliminary action provides mechanical support during subsequent processing steps, enabling more straightforward and less complex grinding or thinning operations. The support structure is prepared in advance to facilitate the main thinning operation without requiring complex in-process adjustments.
3Ease of operation
If auxiliary carriers are bonded onto wafer surface for mechanical stability, then handling becomes easier, but device complexity increases
Solution Approach 1:
The support structure is designed with a segmented or modular architecture that includes a carrier portion and a connection portion. This segmentation allows the support structure to be attached only to specific regions of the wafer (such as the peripheral area), rather than covering the entire surface. The segmented design reduces the complexity of attachment while maintaining mechanical stability during handling and processing.
Data Source
AI summary
A method of manufacturing a semiconductor device includes: providing a silicon carbide substrate that includes device regions and a grid-shaped kerf region laterally separating the device regions; forming a mold structure on a backside surface of the grid-shaped kerf region; forming backside metal structures on a backside surface of the device regions; and separating the device regions, wherein parts of the mold structure form frame structures laterally surrounding the backside metal structures.