Deep Trench Isolation Layout for Compact BCD Chip Areas
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Solution Overview
Problem
Integrating different voltage semiconductor devices on a single chip poses challenges due to increased BCD layout area requirements for electrical isolation, which occupies valuable chip real estate and risks damage to low voltage devices from high voltage proximity.
Innovation Solution
A single, continuous deep trench isolation structure with rounded corners and intersections is used to electrically isolate BCD layout areas, reducing the overall layout area and minimizing sidewall oxide thickness asymmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional isolation structures are used to electrically isolate BCD layout areas, then electrical isolation is achieved, but the layout area increases and valuable chip real estate is occupied
Solution Approach 1:
The patent transitions from planar isolation structures to a three-dimensional deep trench isolation structure that extends vertically into the substrate. By utilizing the vertical dimension, the isolation effectiveness is enhanced while the horizontal footprint is minimized, allowing compact BCD layout areas with sufficient electrical isolation between high voltage and low voltage regions
Solution Approach 2:
The deep trench isolation structure embeds multiple functional layers within a single vertical structure. The trench contains stacked isolation regions at different depths, each providing isolation for specific voltage levels, effectively nesting multiple isolation functions within one compact structure that defines the BCD layout area perimeter
2Area of stationary object
If deep trench isolation structures are used to reduce layout area, then chip footprint is reduced, but manufacturing complexity increases
Solution Approach 1:
The deep trench isolation structure is formed early in the manufacturing process sequence, establishing the isolation regions and BCD layout area boundaries before subsequent device fabrication steps. This preliminary formation of the trench structure with stacked isolation regions simplifies later processing by providing a pre-defined isolation framework that guides subsequent device formation
Solution Approach 2:
The single deep trench isolation structure performs multiple functions simultaneously: it provides electrical isolation for different voltage levels, defines the BCD layout area perimeter, and creates a standardized template for device placement. This multi-functional structure reduces overall manufacturing complexity by consolidating what would otherwise require multiple separate isolation structures
Data Source
AI summary
Devices and methods of manufacture for a deep trench layout area-saving semiconductor structure for use with bipolar-CMOS-DMOS (BCD) devices. A semiconductor device may comprise a first BCD device formed within a first perimeter of a first BCD layout area, and a deep trench isolation structure defining the first perimeter of the first BCD layout area, in which the deep trench isolation structure may comprise a first rounded corner that may define a first corner of the first BCD layout area. A semiconductor device may comprise, a substrate, BCD device formed on the substrate, and a deep trench isolation structure laterally surrounding the BCD device. The deep trench isolation structure, with respect to a top-down view, may comprise vertical portions, horizontal portions, a âTâ-shaped intersection connecting at least one vertical portion and at least one horizontal portion, and a cross-shaped intersection connecting two vertical portions and two horizontal portions.