Integrated Circuit Metal Routing via Double Patterning
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Solution Overview
Problem
The increasing density of integrated circuits (ICs) poses challenges in design and fabrication due to the complexity of routing conductive traces, leading to difficulties in achieving efficient packing density and reducing manufacturing errors.
Innovation Solution
Implementing a system and method for layout design that routes all metal lines in one direction on each metal layer, utilizing double patterning to increase packing efficiency and relax pitch requirements, thereby enhancing the regularity of metal structures and reducing the risk of manufacturing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If increasing IC density is implemented, then speed and functionality are improved, but design and fabrication complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the metal line routing into two separate photolithographic patterning steps (first and second photomasks). This allows the complex dense routing to be broken down into manageable segments that can be fabricated with standard pitch requirements, thereby enabling higher IC density without proportionally increasing fabrication complexity
Solution Approach 2:
The patent introduces a temporal dimension by using sequential patterning steps. Instead of attempting to pattern all metal lines in a single step, the process uses two separate photolithography steps taken at different times, allowing complex routing to be achieved through time-based separation of the patterning operations
2Ease of manufacture
If conventional single photomask patterning is used, then fabrication process is simple, but pitch requirements are stringent and packing density is limited
Solution Approach 1:
The fabrication process is segmented into two separate photolithography patterning steps using first and second photomasks. This segmentation relaxes the pitch requirements for each individual mask, allowing standard fabrication processes to achieve higher overall packing density that would be impossible with single-mask patterning
Solution Approach 2:
The first photomask pattern is formed as a preliminary step before the second photomask pattern. This preliminary action establishes part of the metal line routing, allowing the second patterning step to complete the dense routing configuration with relaxed pitch constraints
Data Source
AI summary
An integrated circuit includes a first and a set of conductive traces, and a first conductive feature. The second set of conductive traces includes a first conductive trace of the second set of conductive traces corresponding to a gate terminal of a first p-type transistor, and a second conductive trace of the second set of conductive traces corresponding to a gate terminal of a first n-type transistor. The first conductive feature corresponds to at least a first contact of a first dummy transistor. The first conductive trace of the second set of conductive traces is electrically coupled to the second conductive trace of the second set of conductive traces by at least the first conductive feature. The first n-type transistor being part of a first transmission gate. The first p-type transistor being part of a second transmission gate.