TSV Diffused Isolation Well Reduces Parasitic Capacitance
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Solution Overview
Problem
Conventional through-silicon via (TSV) structures in semiconductor devices face significant parasitic capacitance issues due to their large size, leading to vulnerability to substrate noise, which existing solutions attempt to address with extra shielding, increasing costs and lowering throughput.
Innovation Solution
A TSV structure surrounded by a diffused insulation well with a concentration gradient of dopant impurities, formed through multiple diffusion operations, reduces parasitic capacitance by creating a well region of opposite dopant type surrounding the conductive material, thereby minimizing capacitance effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric layer is used to surround TSV, then TSV structure is formed, but parasitic capacitance is significant and substrate noise vulnerability increases
Solution Approach 1:
The patent applies local quality by creating a diffused isolation well with a concentration gradient of dopant impurities specifically around the TSV structure. This localized modification of the substrate's electrical properties in the region surrounding the TSV reduces parasitic capacitance without affecting other areas of the semiconductor device, thereby addressing substrate noise vulnerability while maintaining overall device functionality.
Solution Approach 2:
The patent changes the electrical parameters of the substrate by introducing a diffused isolation well with controlled dopant concentration gradients. By modifying the dopant impurity concentration in the region surrounding the TSV, the patent alters the electrical characteristics to reduce parasitic capacitance, transforming the substrate's properties to mitigate noise vulnerability.
2Reliability
If extra shielding is added to reduce parasitic capacitance, then capacitance effects are compensated, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the shielding function from separate additional shielding structures and integrates it directly into the substrate through the diffused isolation well. By forming the isolation well during the TSV fabrication process itself, the patent eliminates the need for separate shielding layers and associated masking operations, reducing manufacturing complexity while maintaining capacitance compensation.
Solution Approach 2:
The patent merges the isolation well formation with the TSV fabrication process by using the same masking and diffusion steps. The diffused isolation well is created as part of the TSV structure formation, combining multiple functions (isolation, capacitance reduction) into a single integrated structure, thereby reducing overall device complexity and manufacturing steps.
3Reliability
If extra shielding and masking operations are performed, then parasitic capacitance is reduced, but manufacturing throughput decreases
Solution Approach 1:
The patent performs preliminary action by forming the diffused isolation well during the initial TSV fabrication steps, before subsequent processing steps are performed. The isolation well is created using the same masking and diffusion operations that define the TSV structure, so no additional masking or processing steps are required later, thereby maintaining high manufacturing throughput while achieving capacitance reduction.
Solution Approach 2:
The patent makes the masking and diffusion operations universal by using them to achieve multiple objectives simultaneously: defining the TSV structure and creating the diffused isolation well. This multi-functionality eliminates the need for separate dedicated steps for isolation well formation, maintaining manufacturing efficiency while achieving parasitic capacitance reduction.
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 diffused insulation well effectively reduces parasitic capacitance, enhancing the reliability of TSV structures without the need for additional shielding, thus improving manufacturing throughput and reducing costs.
Implementation Method 1
The diffusion well may include a concentration gradient of one dopant impurity. The diffusion well may be formed by one or multiple diffusion operations
Data Source
AI summary
A semiconductor device and method for forming the same provide a through silicon via (TSV) surrounded by a dielectric liner. The TSV and dielectric liner are surrounded by a well region formed by thermal diffusion. The well region includes a dopant impurity type opposite the dopant impurity type of the substrate. The well region may be a double-diffused well with an inner portion formed of a first material and with a first concentration and an outer portion formed of a second material with a second concentration. The surrounding well region serves as an isolation well, reducing parasitic capacitance.