Large Die Wafer Stitching Across Dummy Dicing Margins

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Solution Overview

Problem

Conventional photolithography steppers are limited by their maximum field of exposure, making it challenging to fabricate large IC dies that exceed this size, which is necessary for applications like high-speed computing.

Innovation Solution

The method involves forming a large die by stitching together multiple die portions, each with a size equal to or smaller than the stepper's maximum field of exposure. These die portions include a substrate, a dielectric layer, and a first metal layer with to-be-interconnected metal layers. A second metal layer is formed with inter-die interconnecting metal layers that cross dummy dicing margins and connect with the adjacent die portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If multiple die portions are stitched together to form large dies exceeding the stepper's maximum field of exposure, then the die size can be increased for high-speed computing applications, but the interconnection complexity and functional integration between die portions deteriorate

Engineering Contradiction:

Improvedie sizeVSAvoidinterconnection complexity

Core Design Contradiction:

Area of moving objectVSDevice complexity

Solution Approach 1:

The large die is segmented into multiple die portions (first die portion, second die portion, etc.), each within the stepper's exposure field. These portions are stitched together through dummy dicing margins that contain interconnection structures, allowing the overall die to exceed the maximum field of exposure while maintaining manageable interconnection complexity through structured segmentation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Interconnection structures are embedded within the dummy dicing margins, utilizing the vertical dimension and the margin space between die portions. This allows electrical connections to be established between adjacent die portions through the dummy margins rather than requiring complex surface-level interconnections, thereby reducing interconnection complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Area of moving object

If multiple die portions are stitched together to form large dies, then larger die size is achieved, but the electrical signal interconnection quality between die portions deteriorates

Engineering Contradiction:

Improvedie sizeVSAvoidelectrical signal interconnection quality

Core Design Contradiction:

Area of moving objectVSReliability

Solution Approach 1:

Interconnection structures are pre-formed within the dummy dicing margins during the die fabrication process, before the actual stitching occurs. This preliminary preparation ensures that when die portions are stitched together, reliable electrical signal interconnection is already established through the pre-configured interconnection structures in the dummy margins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dummy dicing margins serve as intermediary structures between adjacent die portions. These margins contain interconnection structures that mediate the electrical signal transmission between die portions, ensuring reliable interconnection while allowing the die portions to be stitched together to form larger dies.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Area of moving object

If multiple die portions are stitched together to form large dies, then die size increases for high-speed computing applications, but the functional integration between die portions deteriorates

Engineering Contradiction:

Improvedie sizeVSAvoidfunctional integration

Core Design Contradiction:

Area of moving objectVSAdaptability or versatility

Solution Approach 1:

The dummy dicing margins serve multiple functions: they provide physical spacing between die portions, contain interconnection structures for electrical signaling, and enable the stitching process. This multi-functionality allows die portions to be integrated with enhanced functional versatility, supporting various applications including high-speed computing while maintaining compact design.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 approach enables large die level interconnection, optimizing electrical signal interconnection, and increasing functional integration, thus allowing the fabrication of full-size three-dimensionally integrated dies with enhanced flexibility and compatibility.

Implementation Method 1

exposing the die portions successively one by one using a first photomask module

Methodology Applied

Scientific EffectPhotolithography: Photopolymerisation

Data Source

PatentUS12322707B2Large die wafer, large die and method of forming the same

Publication Date: 2025.06.03 WUHAN XINXIN SEMICON MFG CO LTD

AI summary

The present invention provides a large die, a method of forming the large die and a large die wafer. The method includes: providing a wafer containing a plurality of large dies each having a size greater than that of a maximum field of exposure of a stepper, each large die including at least two die portions to be stitched together, the die portions including a substrate and a first metal layer, the first metal layer including at least to-be-interconnected metal layers for interconnection of the die portions; and forming a second metal layer including at least inter-die interconnecting metal layers crossing dummy dicing margins between adjacent die portions and coming into electrical connection with the to-be-interconnected metal layers of the adjacent die portions. The present invention allows interconnection of the die portions to be stitched together in each large die.