Capacitor Recess Protective Layer for Semiconductor Stability
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Solution Overview
Problem
In semiconductor devices with mixed circuits, the variation in shape at the upper end portion of the capacitor recess leads to variations in capacitance due to the low mechanical strength of the interlayer insulating layer, which is exacerbated by the use of low-dielectric-constant films.
Innovation Solution
A protective layer with a higher dielectric constant is introduced at the periphery of the capacitor recess, made of materials like silicon oxide, to enhance mechanical strength and reduce shape variation, thereby stabilizing the capacitor's capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a low-dielectric-constant film is used as an interlayer insulating layer to reduce parasitic capacitance, then the operation speed is improved, but the mechanical strength decreases leading to shape variation at the recess upper end
Solution Approach 1:
The patent applies local quality by forming a protective layer with high mechanical strength specifically at the upper end portion of the capacitor recess where shape variation occurs, while the rest of the interlayer insulating layer maintains low dielectric constant for reduced parasitic capacitance. This localized reinforcement solves the mechanical strength problem without compromising the overall electrical performance.
Solution Approach 2:
The patent uses composite materials by combining a low-dielectric-constant film (such as fluorinated silicate glass) for the interlayer insulating layer with a protective layer made of different material having high mechanical strength. This composite structure allows simultaneous achievement of low parasitic capacitance and high mechanical strength at critical locations.
2Object-generated harmful factors
If a low-dielectric-constant film is used to reduce parasitic capacitance, then the capacitance between wirings is reduced, but the shape variation at the recess upper end increases
Solution Approach 1:
The protective layer is formed locally at the upper end portion of the recess to maintain shape precision where it is most needed, while allowing the rest of the structure to use low-dielectric-constant material for reduced parasitic capacitance. This localized approach maintains manufacturing precision without compromising electrical performance.
Solution Approach 2:
The protective layer is formed beforehand to prevent shape variation at the recess upper end before the capacitor formation process. This preventive measure ensures that the low-dielectric-constant film does not cause subsequent shape instability during processing.
3Object-generated harmful factors
If the interlayer insulating layer has low mechanical strength, then the parasitic capacitance is low, but the variation in capacitance of the capacitor increases
Solution Approach 1:
The protective layer provides localized mechanical support at the recess upper end to prevent shape variation that would cause capacitance variation, while the low-dielectric-constant interlayer insulating layer maintains low parasitic capacitance. This resolves the contradiction between low parasitic capacitance and high capacitance stability.
Solution Approach 2:
The protective layer acts as an intermediary element between the low-dielectric-constant interlayer insulating layer and the capacitor structure. It provides the necessary mechanical support to ensure capacitance stability without interfering with the low parasitic capacitance property of the main insulating layer.
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 use of a high dielectric constant protective layer reduces capacitance variation and improves the reliability of semiconductor devices by maintaining the performance of the wiring in the logic circuit portion and reducing parasitic capacitance.
Implementation Method 1
the periphery of the upper end portion of the recess is protected by a protective layer which has a dielectric constant greater than that of the insulating layer and which is made of a material having high mechanical strength
Implementation Method 2
Variation in the shape of the upper end portion of the opening portion of the hole may cause variation in capacitance of the capacitor
Implementation Method 3
An interlayer insulating layer having wirings buried therein are required to have a low dielectric constant in order to reduce the parasitic capacitance between wirings
Data Source
AI summary
To provide a semiconductor device featuring reduced variation in capacitor characteristics. In the semiconductor device, a protective layer is provided at the periphery of the upper end portion of a recess (hole). This protective layer has a dielectric constant higher than that of an insulating layer placed in the same layer as the protective layer and configuring a multilayer wiring layer placed in a logic circuit region.