Optical Sensor Redistribution Chip Structure Resists Wire-Bonding Forces
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Solution Overview
Problem
Conventional optical sensors experience defects during wire-bonding due to external forces exerted on the periphery of the large-sized die, leading to structural issues and potential short circuits.
Innovation Solution
The optical sensor design incorporates a redistribution chip structure with an embedded first electronic chip, a sensor chip, a light-permeable sheet, and metal wires, where the sensor chip is supported by the redistribution chip structure to resist external forces, and the package body retains the light-permeable sheet above the sensor chip, preventing defects and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire-bonding is performed on the periphery portion of the large-sized die, then electrical connection is achieved, but external forces cause defects within the optical sensor
Solution Approach 1:
The patent introduces a redistribution chip structure as an intermediary component between the substrate and the sensor chip. This redistribution chip includes an insulating body with embedded electronic chips and redistribution layers that provide electrical connection pathways. By using this intermediary structure, the wire-bonding process is relocated to the redistribution chip rather than directly on the sensor chip periphery, thereby eliminating the harmful external forces during wire-bonding while maintaining electrical connectivity.
Solution Approach 2:
The patent segments the electrical connection function by separating the wire-bonding operation from the sensor chip. The redistribution chip structure divides the connection pathway into multiple stages: substrate to redistribution chip, and redistribution chip to sensor chip. This segmentation allows the wire-bonding to occur on the redistribution chip where it does not exert harmful forces on the sensor chip, while still achieving the required electrical connections.
2Area of moving object
If the sensor chip is larger than the first electronic chip, then sensing area is increased, but the periphery portion becomes suspended over the substrate causing vulnerability to external forces
Solution Approach 1:
The redistribution chip structure serves as a mediator that provides structural support to the larger sensor chip. The insulating body of the redistribution chip extends beyond the boundaries of the first electronic chip, creating an extended support platform. This allows the sensor chip to have a larger sensing area while the redistributed chip structure prevents the periphery from being suspended, thereby maintaining structural strength and resistance to external forces.
Data Source
AI summary
Disclosed is an optical sensor including a substrate, a redistribution chip structure disposed on the substrate, a sensor chip disposed on the redistribution chip structure, a light-permeable sheet arranged above the sensor chip, metal wires electrically connecting the substrate and the sensor chip, and a package body disposed on the substrate. The redistribution chip structure includes an insulating body, a first electronic chip embedded in the insulating body, and a redistribution layer (RDL) connected to bottoms of the insulating body and the first electronic chip. The RDL is fixed onto the substrate in a flip-chip manner. A projected region defined by orthogonally projecting a sensing area of the sensor chip onto the redistribution chip structure is located inside outer edges of the redistribution chip structure. The redistribution chip structure, the sensor chip, a part of the light-permeable sheet, and the metal wires are embedded in the package body.