Microlens Dummy Structures for Passivation Film Stress Relief
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Solution Overview
Problem
In solid-state imaging devices, the mismatch between the passivation film and the microlens underlying layer can cause the passivation film to crack or delaminate, reducing the reliability and functionality of the devices.
Innovation Solution
Incorporating dummy structures around the bond pad area within the microlens layer, with varying microlens elements in the sensing, pad, and peripheral regions, to prevent passivation film failures by ensuring compatibility and reducing stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dummy structures are added to the microlens layer to prevent passivation film failures, then the reliability and functionality of the device are enhanced, but the device complexity increases
Solution Approach 1:
The patent applies dummy structures locally at specific positions (such as around bond pads or in peripheral regions) rather than uniformly across the entire device. This localized approach provides stress relief and prevents passivation film failures only where needed, enhancing reliability while minimizing the increase in overall device complexity.
Data Source
AI summary
A solid-state imaging device has a sensing region, a pad region and a peripheral region between the sensing region and the pad region. The solid-state imaging device includes a plurality of photoelectric conversion elements formed in a semiconductor substrate and disposed in the sensing region, and a bond pad disposed on the semiconductor substrate and in the pad region. The solid-state imaging device further includes a microlens layer disposed above the semiconductor substrate. The microlens layer includes a microlens array in the sensing region and a first dummy structure in the pad region. The first dummy structure includes a plurality of first microlens elements disposed to surround an area of the bond pad. Moreover, the solid-state imaging device includes a passivation film conformally formed on a top surface of the microlens layer.