Porous Dielectric Stack Layout for Lower Parasitic Capacitance
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Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in achieving improved quality, yield, performance, and reliability while reducing complexity, particularly due to issues with parasitic capacitance and dielectric constant in existing designs.
Innovation Solution
A semiconductor device is designed with a substrate featuring a bottom porous dielectric layer, a top porous dielectric layer, and a middle porous dielectric layer, where the porosity of the top layer is greater than the middle layer, and the middle layer's porosity is greater than the bottom layer, along with conductive structures, to reduce parasitic capacitance by employing low dielectric constant materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric layers are used in scaled-down semiconductor devices, then device complexity is reduced, but parasitic capacitance increases and performance deteriorates
Solution Approach 1:
The patent employs porous dielectric layers with controlled porosity gradients to reduce the dielectric constant and thereby reduce parasitic capacitance. The porous structure introduces voids that lower the effective dielectric constant compared to conventional solid dielectric layers, directly addressing the harmful effect of parasitic capacitance in scaled-down devices.
Solution Approach 2:
The patent changes the physical parameter of the dielectric layer by creating a porosity gradient, where porosity varies through the thickness of the layer. This parameter change results in a gradient dielectric constant, optimizing the balance between reducing parasitic capacitance and maintaining electrical performance.
2Object-affected harmful factors
If porosity of dielectric layers is increased to reduce dielectric constant, then parasitic capacitance is reduced, but outgassing occurs and reliability deteriorates
Solution Approach 1:
The patent applies local quality by creating a porosity gradient where different regions of the dielectric layer have different porosity levels. The bottom portion has lower porosity to prevent outgassing and maintain structural integrity, while the top portion has higher porosity to reduce parasitic capacitance. This spatial variation in porosity allows simultaneous optimization of both reliability and capacitance reduction.
Solution Approach 2:
The intermediate porosity layer acts as a mediator between the low-porosity bottom layer and high-porosity top layer, providing a gradual transition that prevents sudden outgassing while maintaining the overall low dielectric constant. This intermediate structure balances the conflicting requirements of preventing outgassing and reducing parasitic capacitance.
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 design effectively reduces parasitic capacitance, enhancing the performance of the semiconductor device and improving its reliability by using low dielectric constant materials in the porous layers, while the barrier layers prevent outgassing and serve as etching stops.
Implementation Method 1
A porosity of the top porous dielectric layer is greater than a porosity of the middle porous dielectric layer. The porosity of the middle porous dielectric layer is greater than a porosity of the bottom porous dielectric layer.
Implementation Method 2
performing an energy treatment to turn the bottom energy-removable layer into a bottom porous dielectric layer, turn the top energy-removable layer into a top porous dielectric layer, and form a middle porous dielectric layer between the bottom porous dielectric layer and the top porous dielectric layer
Data Source
AI summary
The present application discloses a semiconductor device and a method for fabricating the semiconductor device. The semiconductor device includes a substrate; a first bottom conductive layer positioned in the substrate; a bottom porous dielectric layer positioned on the substrate; a top porous dielectric layer positioned on the bottom porous dielectric layer; a middle porous dielectric layer positioned between the bottom porous dielectric layer and the top porous dielectric layer; and a mixing-area conductive structure positioned along the top porous dielectric layer, the middle porous dielectric layer, and the bottom porous dielectric layer, and positioned on the first bottom conductive layer. A porosity of the top porous dielectric layer is greater than a porosity of the middle porous dielectric layer. The porosity of the middle porous dielectric layer is greater than a porosity of the bottom porous dielectric layer.