Semiconductor Die Fiducial Alignment Slots
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Solution Overview
Problem
The challenge in semiconductor manufacturing is maintaining precise placement of semiconductor die on a temporary carrier during the encapsulation process, as existing methods are limited by die placement tolerance and can result in misalignment or movement, affecting subsequent manufacturing processes.
Innovation Solution
The method involves forming fiducial patterns and alignment slots on the carrier and repassivation layer, allowing the semiconductor die to be precisely aligned and locked in place, ensuring accurate positioning even during encapsulation, and subsequently removing the carrier and adhesive layers after encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high precision die bonder is used for placing semiconductor die on a temporary carrier, then the initial placement precision is improved, but the die may still shift during the encapsulation process
Solution Approach 1:
Alignment slots are formed in the repassivation layer before the die placement process. These pre-formed slots guide the die into precise positions and lock them in place, preventing any shifting during subsequent encapsulation processes. The alignment slots act as a preliminary structural feature that ensures both initial precision and long-term stability.
Solution Approach 2:
The alignment slots serve as an intermediary mechanism between the die and the carrier. Rather than relying solely on the die bonder's precision or adhesive strength, the alignment slots provide a mechanical interface that guides and secures the die position, mediating the connection and preventing movement during processing.
2Stability of the object's composition
If adhesive layers are used to secure die on the carrier, then the die is held in place, but the adhesive may interfere with subsequent manufacturing processes
Solution Approach 1:
The solution segments the positioning function from the adhesive function. Alignment slots provide the mechanical positioning and stability, while the adhesive layer's role is reduced to simple bonding. This segmentation allows the adhesive to be easily removed or bypassed in subsequent processes, as the alignment slots continue to provide structural support and position stability.
Solution Approach 2:
The critical positioning function is extracted from the adhesive layer and transferred to the alignment slots. By taking out the positioning responsibility from the adhesive, the adhesive layer becomes a simpler, more easily removable component that does not interfere with subsequent manufacturing processes that require precise access to the die.
3Stability of the object's composition
If the carrier and adhesive layer are kept throughout the manufacturing process, then die placement stability is maintained, but the complexity of the manufacturing process increases
Solution Approach 1:
Alignment slots are formed in advance in the repassivation layer, creating a self-aligning structure that simplifies subsequent die placement. This preliminary structural feature eliminates the need for complex real-time alignment procedures and reduces the complexity of the overall manufacturing process while maintaining stability.
Solution Approach 2:
The alignment slots provide self-aligning and self-locking functionality during die placement. The die automatically engages with the pre-formed slots, eliminating the need for complex external alignment mechanisms or procedures. This self-service approach reduces manufacturing process complexity while ensuring precise and stable die positioning.
Data Source
AI summary
A semiconductor device has an adhesive layer depositing over a temporary carrier. A plurality of fiduciary patterns is formed over the adhesive layer. A repassivation layer is formed over semiconductor die. The repassivation layer may be a plurality of discrete regions. Alignment slots are formed in the repassivation layer. The fiducial patterns and alignment slots have slanted sidewalls. Leading with the repassivation layer, the semiconductor die is placed onto the carrier so that the alignment slots envelope and lock to the fiducial patterns. Alternatively, a die without the repassivation layer is placed between the fiducial patterns. An encapsulant is deposited over the semiconductor die while the die remain locked to the fiducial patterns. The carrier, adhesive layer, and fiducial patterns are removed after depositing the encapsulant. An interconnect structure is formed over the repassivation layer to electrically connect to contact pads on the semiconductor die.