Via Layout Shifting During Optical Proximity Corrections

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Solution Overview

Problem

Optical proximity corrections (OPC) techniques in integrated circuit manufacturing result in significant movement and sizing changes of metal lines, leading to reduced via-metal overlap and increased risk of electrical shorts, which compromises the process window and yield.

Innovation Solution

A pitch-aware correction (PAC) algorithm is employed to shift vias and extend metal lines, maximizing via-metal overlap while minimizing electrical shorting risk, using a rule-based equation to predict metal line movements and constrain via positions to ensure optimal overlap and avoid patterning violations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If OPC techniques are applied to improve printability, then manufacturing precision is improved, but via-metal overlap is reduced and electrical short risk increases

Engineering Contradiction:

ImproveprintabilityVSAvoidvia-metal overlap

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing via chasing - adjusting via positions - before final patterning. The system predicts metal line shifts from OPC, calculates required via position adjustments in advance, and applies these corrections to maintain proper via-metal overlap before the actual manufacturing process begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using a iterative process where via positions are adjusted based on predicted metal shifts, then re-evaluating overlap metrics, and repeating until optimal overlap is achieved. The system continuously monitors via-metal overlap and electrical short risk, using this information to refine via position adjustments.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If OPC techniques are applied to improve printability, then manufacturing precision is improved, but risk of electrical shorts increases

Engineering Contradiction:

ImproveprintabilityVSAvoidelectrical short risk

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by proactively counteracting the harmful effect of electrical shorts before they can occur. The system predicts which vias are at risk of electrical shorts due to metal line shifts, and pre-adjusts their positions to maintain safe spacing from adjacent metal lines, thereby preventing the harmful effect before manifesting.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system continuously monitors electrical short risk metrics and uses this feedback to refine via position adjustments. By iteratively evaluating short risk and adjusting via positions accordingly, the system reduces electrical short risk while maintaining the benefits of OPC for printability.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If via positions are adjusted to maintain overlap, then via-metal overlap is improved, but processing time increases

Engineering Contradiction:

Improvevia-metal overlapVSAvoidprocessing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by focusing via chasing efforts only on critical vias that require adjustment to maintain overlap, rather than uniformly adjusting all vias. The system identifies and prioritizes vias most affected by metal shifts, applying corrections only where necessary to maintain overlap metrics while minimizing overall processing time.

Inventive Principle:

Principle #16Partial or excessive action

4Manufacturing precision

If via positions are adjusted to maintain overlap, then via-metal overlap is improved, but device complexity increases

Engineering Contradiction:

Improvevia-metal overlapVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent simplifies the overall process by performing preliminary via position adjustments based on predicted metal shifts before final patterning. This preliminary action consolidates multiple adjustment steps into a single coordinated process, reducing the complexity of subsequent manufacturing steps while maintaining via-metal overlap.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240334611A1Enhanced rule-based shifting of integrated circuit vias layouts to match metals during optical proximity corrections

Publication Date: 2024.10.03 INTEL CORP

AI summary

This disclosure describes systems, methods, and devices related to shifting layouts of electronic circuit vias during optical proximity corrections (OPC). A method may include identifying a first metal line, of an electronic circuit, drawn at a first position; identifying a second metal line, of the electronic circuit, drawn at a second position; identifying a via drawn at a third position extending between the first metal line and the second metal line; determining a fourth position to which the first metal line is to move from the first position; determining a fifth position to which the second metal line is to move from the second position; determining, based on the fourth position, the fifth position, a sixth position to which the via is to move from third position; and generating a layout for generating a photomask for the via at the sixth position.