Solid-State Image Pickup Light Shielding Member for Oblique Light
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In solid-state image pickup apparatuses with global electronic shutter functions, oblique light can intrude into the charge storage unit through openings in the light shielding member, causing noise and degrading image quality.
Innovation Solution
A light shielding member with a first part covering the charge storage unit and at least one gate electrode, and a second part extending between the gate electrodes, is disposed to suppress oblique light incidence, improving light shielding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light shielding member is disposed on an interlayer insulating film including a wiring layer, then the charge storage unit is covered, but oblique light can easily intrude into the charge storage unit via an opening of the light shielding member
Solution Approach 1:
The light shielding member is extended in the vertical dimension by adding a lower portion that protrudes downward from the upper surface toward the charge storage unit. This three-dimensional structure blocks oblique light paths that would otherwise reach the charge storage unit through openings in the upper surface, effectively addressing the light intrusion problem without compromising image quality.
2Ease of operation
If an opening for a plug of the contact is formed in the light shielding member, then voltage can be supplied to the element, but it makes it easier for oblique light to intrude into the charge storage unit
Solution Approach 1:
The lower portion of the light shielding member extends vertically downward to block oblique light paths, while openings are formed in the upper surface for voltage supply. The vertical extension creates a shielded environment that prevents oblique light from reaching the charge storage unit through the openings, thus maintaining both electrical connectivity and light shielding performance.
3Ease of manufacture
If the light shielding member has a simple flat structure, then manufacturing is simple, but oblique light can intrude into the charge storage unit
Solution Approach 1:
The light shielding member incorporates a lower portion that protrudes downward from the upper surface, creating a three-dimensional structure. This design blocks oblique light paths while maintaining compatibility with standard semiconductor manufacturing processes, thus achieving improved light shielding without significantly complicating the manufacturing procedure.
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
The structure effectively reduces oblique light intrusion into the charge storage unit, enhancing image quality by minimizing noise and dark current.
Implementation Method 1
a light shielding member including a first part and a second part wherein the first part is disposed over the charge storage unit and at least over the first gate electrode and the second gate electrode, and wherein the second part is disposed between the first gate electrode and the second gate electrode such that the second part extends from the first part toward a surface of the semiconductor substrate
Data Source
AI summary
A solid-state image pickup apparatus includes a photoelectric conversion unit, a charge storage unit, and a floating diffusion unit, all disposed on a semiconductor substrate. The solid-state image pickup apparatus further includes a first gate electrode disposed on the semiconductor substrate and extending between the photoelectric conversion unit and charge storage unit, and a second gate electrode disposed on the semiconductor substrate and extending between the charge storage unit and the floating diffusion unit. The solid-state image pickup apparatus further includes a light shielding member including a first part and a second part, wherein the first part is disposed over the charge storage unit and at least over the first gate electrode or the second gate electrode, and the second part is disposed between the first gate electrode and the second gate electrode such that the second part extends from the first part toward a surface of the semiconductor substrate.