Interposer Alignment Mark Layout With Peripheral Metal Pad

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Solution Overview

Problem

The mechanical integrity of semiconductor packages is compromised by cracking in stacked dielectric layers near alignment marks during interposer fabrication, leading to defects such as abnormal metal plating and die saw chipping, which reduces yields and increases costs.

Innovation Solution

A peripheral metal pad structure is formed around alignment marks in dielectric layers to enhance adhesion and mechanical integrity, reducing the likelihood of crack formation in the dielectric material stack.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If alignment marks are used in the dielectric layers during interposer fabrication, then lithographic alignment and patterning can be performed, but cracking occurs in the stacked dielectric layers near the alignment marks, leading to defects such as abnormal metal plating and die saw chipping

Engineering Contradiction:

Improvelithographic alignment precisionVSAvoidmechanical integrity of dielectric layer stack

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A peripheral metal pad structure is introduced as an intermediary element between the alignment mark and the dielectric layers. This metal pad serves as a mediator that absorbs mechanical stress and prevents crack propagation into the dielectric stack, thereby protecting the structural integrity while allowing the alignment mark to remain functional for lithographic purposes

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The peripheral metal pad structure is formed in advance around the alignment mark before the dielectric layers are stacked. This pre-positioned metal pad acts as a cushioning element that anticipates and prevents crack formation during subsequent fabrication processes, particularly during die singulation and thermal cycling

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Device complexity

If multiple dielectric layers are stacked during interposer fabrication, then complex interconnect structures can be formed, but the mechanical integrity is compromised by cracking near alignment marks

Engineering Contradiction:

Improveinterconnect structure complexityVSAvoidmechanical strength of dielectric layer stack

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The interposer structure is segmented into distinct functional zones: alignment mark regions, peripheral metal pad regions, and dielectric layer regions. This segmentation isolates the alignment marks from the stacked dielectric layers, allowing the dielectric layers to be stacked for complex interconnect structures while the peripheral metal pads provide mechanical support and prevent cracking

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If alignment marks are present in the dielectric layers, then lithographic patterning can be performed, but defects such as abnormal metal plating and die saw chipping occur

Engineering Contradiction:

Improvelithographic patterning precisionVSAvoiddefects including abnormal metal plating and die saw chipping

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The peripheral metal pad acts as an intermediary barrier between the alignment mark and the dielectric layers, preventing the transmission of mechanical stresses that cause defects. This mediator structure allows the alignment mark to remain exposed for lithographic patterning while blocking crack propagation that would otherwise cause abnormal metal plating and die saw chipping

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The peripheral metal pad structure is formed in advance to counteract the harmful effects of crack formation. By pre-positioning this stress-absorbing structure around the alignment mark, the patent prevents the initiation and propagation of cracks before they can cause defects during metal plating or die singulation processes

Inventive Principle:

Principle #9Preliminary anti-action

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

The peripheral metal pad structure increases the strength of the dielectric layer stack, minimizing cracking and enhancing the reliability of the interposer, thereby improving yield and reducing production costs.

Implementation Method 1

A peripheral metal pad structure is formed around alignment marks in dielectric layers to enhance adhesion and mechanical integrity

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS20250323174A1Interposer structure for semiconductor package including peripheral metal pad around alignment mark and methods of fabricating same

Publication Date: 2025.10.16 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An interposer for a semiconductor package and a method of fabricating an interposer including a peripheral metal pad surrounding an alignment mark. The alignment mark and the surrounding peripheral metal pad are formed on a first dielectric material layer of the interposer. A second dielectric material layer is located over the first dielectric material layer and at least partially over the peripheral metal pad structure and includes an recess extending around a periphery of the alignment mark. A third dielectric material layer is located over the second dielectric material layer and extends into the recess and contacts the alignment mark, the first dielectric material layer, and optionally a portion of the peripheral metal pad. The peripheral metal pad may enhance the adhesion between the first, second and third dielectric material layers near the alignment mark structure and thereby reduce the likelihood of crack formation.