Semiconductor Gate Pattern Layout for Optical Proximity Correction
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Solution Overview
Problem
Conventional semiconductor fabrication techniques face challenges in maintaining consistent gate lengths due to the optical proximity effect, leading to variations in pattern dimensions, which affect the performance of semiconductor integrated circuits, especially with the miniaturization of devices.
Innovation Solution
A semiconductor device layout is proposed where a standard cell with multiple gate patterns at an equal pitch is positioned next to a diode cell, with the gate patterns terminating near the cell boundary and having equal widths, and the diode cell includes opposite end portions that oppose the standard cell's gate patterns, ensuring shape regularity and minimizing variations in gate length caused by the optical proximity effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography is used to form patterns on semiconductor substrate, then patterns can be formed, but variations in pattern dimensions occur due to optical proximity effect
Solution Approach 1:
The patent applies optical proximity effect correction (OPC) to the mask pattern before photolithography exposure. The mask is designed with pre-corrected dimensions that anticipate the optical distortion, so that after exposure and development, the final pattern achieves the desired gate length precision. This preliminary correction compensates for the optical proximity effect before it occurs during fabrication.
2Manufacturing precision
If optical proximity effect correction is applied to all gate patterns, then gate length precision is improved, but turn around time and processing amount increase
Solution Approach 1:
The patent selectively applies optical proximity effect correction only to specific gate patterns that are adjacent to diode cells, rather than uniformly correcting all gate patterns on the chip. This localized approach targets the problematic areas where gate-length variations most significantly affect performance, while leaving other areas unchanged, thereby reducing the overall processing time and computational resources required for OPC.
3Stability of the object's composition
If gate patterns are standardized with equal pitch, then layout consistency is improved, but design flexibility is reduced
Solution Approach 1:
The patent creates a standardized diode cell layout that can be universally applied adjacent to various types of gate patterns. The diode cell structure itself is designed with standardized dimensions and positioning rules, making it a reusable component that maintains layout consistency across different circuit designs. This standardization provides a universal solution for protecting against optical proximity effects while working within standardized cell libraries.
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
This configuration reliably prevents variations in gate length, reducing the need for post-placement corrections and streamlining the design process, thereby enhancing the operational performance and efficiency of semiconductor integrated circuits.
Implementation Method 1
differences between the designed layout dimensions and the pattern dimensions formed on the semiconductor substrate become large due to an optical proximity effect of the diffracted light
Data Source
AI summary
A standard cell has gate patterns extending in Y direction and arranged at an equal pitch in X direction. End portions of the gate patterns are located at the same position in Y direction, and have an equal width in X direction. A diode cell is located next to the standard cell in Y direction, and includes a plurality of opposite end portions formed of gate patterns that are opposed to the end portions, in addition to a diffusion layer which functions as a diode.