Solid State Imaging Device Void Insulator Film Residue Prevention
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Solution Overview
Problem
In solid state imaging devices, the refinement of semiconductor processes leads to narrower gaps between gate electrodes, causing residues of light shielding films to remain, which can result in leakage and degrade the light shielding property and yield rate.
Innovation Solution
A manufacturing method involving the formation of a void between gate electrodes, with an insulator film covering them, and a light shielding member formed by etching over the insulator film, ensuring the light shielding member is absent on one side of the insulator film, thereby improving flatness and reducing residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gap between gate electrodes is narrowed due to semiconductor process refinement, then device integration density is improved, but residues of light shielding film remain causing leakage and degrading light shielding property
Solution Approach 1:
An insulator film is formed in advance to cover the gate electrodes and fill the gap between them before the light shielding film is deposited. This preliminary action ensures that when the light shielding film is subsequently etched, the insulator film is present to prevent residue formation in the narrow gap, thus maintaining light shielding property while allowing narrow gap design for high integration density
Solution Approach 2:
The insulator film acts as an intermediary substance between the gate electrodes and the light shielding film. It fills the narrow gap between gate electrodes and provides a surface that prevents light shielding film residue during etching, thereby enabling narrow gap design without compromising light shielding effectiveness
2Reliability
If the insulator film thickness is increased to fill the gap between gate electrodes, then residue occurrence is reduced, but the distance between photoelectric conversion unit and light shielding member increases reducing light shielding capability
Solution Approach 1:
The thickness of the insulator film is precisely controlled within a specific range (50nm to 200nm) to achieve optimal balance. This parameter optimization ensures sufficient film coverage to prevent light shielding film residue in narrow gaps while maintaining adequate light shielding capability by limiting the distance between the photoelectric conversion unit and the light shielding member
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
This method enhances the light shielding property and yield rate by preventing residues and maintaining the integrity of the light shielding member, even in narrow gaps, while reducing the thickness of the insulator film to improve the light shielding capability.
Implementation Method 1
forming an insulator film covering the first gate electrode and the second gate electrode
Implementation Method 2
forming a light shielding member by removing a part of the film by etching
Data Source
AI summary
A manufacturing method of a solid state imaging device according to one embodiment includes the steps of forming, on a substrate, a gate electrode of a first transistor and a gate electrode of a second transistor adjacent to the first transistor; forming an insulator film covering the gate electrode of the first transistor and the gate electrode of the second transistor such that a void is formed between the gate electrode of the first transistor and the gate electrode of the second transistor; forming a film on the insulator film; and forming a light shielding member by removing a part of the film by an etching.