Backside Trench Isolation Layout for High-Voltage Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor technologies face challenges in efficiently isolating high voltage devices from surrounding components to prevent electrical interference, crosstalk, and leakage currents, particularly in mixed-signal and high-voltage applications.
Innovation Solution
The integration of backside trench isolation (BDTI) and backside via patterning in a fully depleted bulk process (FVBP) scheme, which involves etching deep trenches in the substrate and filling them with insulating material to create a physical barrier, allowing for seamless power delivery and electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shallow trench isolation (STI) is used to isolate high voltage devices, then electrical isolation is provided, but leakage currents and electrical interference cannot be fully prevented
Solution Approach 1:
The isolation structure is segmented into two distinct parts: STI on the frontside for basic isolation, and BDTI on the backside for enhanced isolation. This segmentation allows each layer to perform its isolation function independently, with BDTI providing an additional barrier that prevents leakage currents and electrical interference that penetrate through STI alone.
Solution Approach 2:
The invention transitions from single-sided isolation (frontside only) to dual-sided isolation by adding BDTI on the backside. This dimensional change creates a three-dimensional isolation architecture where BDTI forms a continuous isolation barrier that extends through the substrate thickness, effectively blocking electrical interference and leakage currents that travel through the substrate.
2Object-generated harmful factors
If deep trenches are etched for backside isolation, then electrical interference is minimized, but manufacturing complexity increases
Solution Approach 1:
The formation of BDTI is merged with the existing backside via patterning process. The same lithography and etching steps used to create backside vias are also used to define the BDTI trenches, combining two manufacturing operations into one unified process flow. This merging reduces the total number of process steps while achieving both electrical isolation and via formation.
Solution Approach 2:
The backside processing steps are designed to serve multiple functions: forming backside vias for electrical connections, creating BDTI trenches for isolation, and preparing the surface for subsequent processing. This multi-functionality reduces manufacturing complexity by eliminating redundant process steps.
3Ease of manufacture
If backside via patterning is integrated with BDTI formation, then manufacturing is simplified, but alignment precision must be maintained
Solution Approach 1:
Alignment marks are defined and registered before the combined via and BDTI patterning process. This preliminary action ensures that the subsequent lithography and etching steps are precisely aligned with the device geometry and with each other, maintaining manufacturing precision while enabling process integration.
Data Source
AI summary
A semiconductor device includes a backside contact, a shallow trench isolation (STI), and a backside dielectric trench isolation (BDTI) below the STI. A top surface of the BDTI is connected to the STI on a backside of a high voltage region of the semiconductor device, a bottom surface of the BDTI is connected to a backside power interconnect, and the BDTI isolates a backside contact from a substrate.