COAG Layout Reliability Test Macro for Gate Oxide Breakdown
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Solution Overview
Problem
Contact over active gate (COAG) layout designs face reliability challenges due to gate oxide breakdown and leakage, which are difficult to evaluate using existing test structures, limiting the robustness of material properties and increasing production costs.
Innovation Solution
The development of reliability test macros for COAG layout designs, including gate-shaped dielectric structures, source/drain regions, and dielectric fill material, allows for the evaluation of material properties by applying voltage and detecting current between gate and source/drain contacts, simulating the isolation of gate workfunction-setting metal and assessing breakdown/leakage robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gate contact is placed over the active area to increase device density, then device density is improved, but material robustness deteriorates due to proximity to source/drain contacts causing breakdown
Solution Approach 1:
The patent introduces a dedicated test macro structure that segments the evaluation process from production devices. This separate test structure allows independent assessment of material robustness between gate and source/drain contacts without affecting the actual device density improvements from COAG layout.
Solution Approach 2:
The patent implements preliminary reliability testing through specially designed test macros before full production. This preliminary action identifies material robustness issues early, preventing breakdown problems in high-density COAG devices while maintaining the density benefits.
2Ease of manufacture
If typical structure designs are used for failure analysis, then manufacturing simplicity is maintained, but measurement capability deteriorates due to inability to evaluate material robustness
Solution Approach 1:
The patent introduces an intermediary test macro structure that mediates between simple manufacturing processes and precise measurement needs. This test structure incorporates specific features like gate contacts over active area with source/drain contacts that enable detailed material evaluation without complicating actual device manufacturing.
Solution Approach 2:
The patent creates a copied version of the COAG structure specifically for testing purposes. This test macro copies the critical geometric relationships and material stack of production devices, enabling accurate material robustness evaluation while keeping production device manufacturing simple.
3Area of stationary object
If COAG layout design is implemented to reduce footprint, then area efficiency is improved, but reliability assessment difficulty increases due to lack of appropriate test structures
Solution Approach 1:
The patent segments the reliability assessment function into a separate test macro, allowing detailed measurement of material robustness in COAG structures without affecting the compact footprint of production devices. The test macro isolates critical regions for measurement while production devices maintain minimal area.
Solution Approach 2:
The patent performs preliminary reliability assessment through dedicated test macros before full production implementation. This preliminary measurement identifies potential breakdown issues in the reduced-footprint COAG design, enabling reliability optimization without increasing device area.
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
Enables effective evaluation of material properties, preventing costly reworks and enhancing production yield by identifying robustness against breakdown/leakage, thus improving the reliability of COAG layout designs.
Implementation Method 1
a dielectric fill material is present in between the gate contacts and the source/drain contacts
Implementation Method 2
Breakdown occurs when the gate oxide loses its insulating properties due to the formation of conductive paths through the material
Data Source
AI summary
Reliability test macros for contact over active gate (COAG) layout designs are provided. In one aspect, a COAG layout design reliability test macro includes: gate-shaped dielectric structures disposed over an active area of a substrate; source/drain regions present on opposite sides of the gate-shaped dielectric structures; source/drain contacts in direct contact with the source/drain regions; a dielectric fill material disposed on the source/drain contacts; and gate contacts present over, and in direct contact with, the gate-shaped dielectric structures in the active area, wherein the dielectric fill material is present in between the gate contacts and the source/drain contacts. Methods of forming and using the present COAG layout design reliability test macros are also provided.