Hybrid Diffusion Library Cells With Fixed Base Layers for ECO Masks
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Solution Overview
Problem
As fabrication technology size decreases, the time and costs associated with programming and fabricating Engineering Change Order (ECO) standard library cells increase due to the need to alter multiple layers and re-fabricate masks in integrated circuits (ICs).
Innovation Solution
The introduction of hybrid diffusion standard library cells with fixed base layers and break regions, along with fixed MEOL interconnects, limits the number of masks that need to be programmed, reducing fabrication time and costs by maintaining constant base layer designs across different IC devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fully custom diffusions are used to accommodate varied transistor locations, then design flexibility is improved, but mask complexity and manufacturing cost increase
Solution Approach 1:
The diffusion layer is segmented into a fixed base diffusion layer and variable upper diffusion layers. The base layer contains diffusion regions at all possible transistor locations, while upper layers activate only the needed regions through selective patterning. This segmentation allows a single mask set to serve multiple design configurations, reducing mask complexity while preserving design flexibility.
Solution Approach 2:
The fixed base diffusion layer serves multiple functions: it provides diffusion regions for all possible transistor locations, establishes a common foundation for various circuit designs, and enables the same mask set to be reused across different device configurations. This multi-functionality reduces the need for custom masks for each design variant.
2Adaptability or versatility
If fully custom diffusions are fabricated for each device, then design flexibility is improved, but manufacturing cost increases
Solution Approach 1:
By segmenting the diffusion structure into fixed base layers and variable upper layers, the patent enables reuse of the expensive base layer fabrication across multiple devices. Only the simpler upper layers require device-specific patterning, significantly reducing per-device manufacturing cost while maintaining design flexibility.
Solution Approach 2:
The fixed base diffusion layer is prepared in advance with all possible diffusion regions formed before device-specific customization. This preliminary action allows subsequent devices to be fabricated using the same base layer with minimal additional processing, reducing overall manufacturing cost.
3Device complexity
If diffusion regions are merged to reduce process steps, then manufacturing complexity is reduced, but transistor location flexibility is lost
Solution Approach 1:
The patent segments the diffusion formation into two distinct stages: a first diffusion process that creates merged diffusion regions for all possible locations, and a second diffusion process that selectively activates specific regions. This segmentation resolves the contradiction by maintaining flexibility through selective activation while using merged regions to simplify the overall process.
Solution Approach 2:
The diffusion structure transitions from a static merged configuration to a dynamic selectively-activated configuration. The first diffusion creates a superset of all possible transistor locations, and the second diffusion dynamically selects which locations are actually used based on the specific device design, maintaining flexibility without requiring fully custom processes.
4Adaptability or versatility
If multiple diffusion regions are kept separate to enable selective activation, then transistor location flexibility is improved, but process complexity increases
Solution Approach 1:
The patent segments the diffusion regions into a fixed base layer containing all possible locations and variable upper layers that enable selective activation. This segmentation allows transistor location flexibility through the upper layers while keeping the base layer simple and reusable, thereby limiting the increase in process complexity.
Data Source
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AI summary
Hybrid diffusion standard library cells, and related systems and methods are disclosed. The hybrid diffusion standard library cells may be fabricated with reduced costs because masks corresponding to fixed base layers remain constant across integrated circuit (IC) devices. In one aspect, a hybrid diffusion standard library cell is provided. The hybrid diffusion standard library cell employs multiple diffusion regions, wherein a break region separates at least two of the multiple diffusion regions. The hybrid diffusion standard library cell includes one or more MEOL interconnects at fixed locations that are configured to connect transistors to a first metal layer. The hybrid diffusion standard library cell includes at least one transistor. Including the break region between multiple diffusion regions helps to limit the locations of the fixed MEOL interconnects, which limits possible locations for base level transistors and fixes the base layer design.