Magnetic Bonding Alignment for Semiconductor Package Structures

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Solution Overview

Problem

Existing semiconductor package structures and fabrication methods are not entirely satisfactory, particularly in terms of alignment precision and reliability in advanced packaging technologies like package on package (PoP), where integrating different or similar function packages is challenging.

Innovation Solution

The use of magnetic pads on semiconductor wafers for self-aligned bonding, where ferromagnetic materials like iron, cobalt, or nickel are magnetized to attract and align the wafers during bonding, enhancing precision and reliability through magnetic bonding structures, along with metal-to-metal and non-metal-to-non-metal bonding processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional bonding methods are used for package on package (PoP) integration, then manufacturing process is simple, but alignment precision and bonding reliability deteriorate

Engineering Contradiction:

Improvealignment precisionVSAvoidbonding process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical alignment and bonding methods with magnetic field-based alignment and magnetic bonding. Magnetic pads with opposite polarities are formed on bonding surfaces, enabling precise alignment through magnetic attraction forces and achieving reliable bonding without complex mechanical positioning systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the bonding interface properties by introducing magnetic pads that alter the physical and chemical characteristics of the bonding surface. This enables controlled magnetic interactions between substrates, transforming the bonding mechanism from purely mechanical/thermal to magnetically-assisted bonding with enhanced precision and reliability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If magnetic pads are used for self-aligned bonding, then alignment precision and bonding reliability improve, but manufacturing process complexity increases

Engineering Contradiction:

Improvebonding reliabilityVSAvoidmanufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple functions into the magnetic pads: alignment reference, bonding force generation, and potential electrical connection. This integration reduces the need for separate alignment marks and bonding mechanisms, simplifying the overall manufacturing process despite the introduction of magnetic materials.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The magnetic pads enable self-aligned bonding where the magnetic attraction forces automatically position the substrates relative to each other during the bonding process. This self-alignment mechanism eliminates the need for complex external alignment systems and reduces manual intervention, improving both reliability and manufacturing efficiency.

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If magnetic bonding is used for die-on-wafer bonding, then alignment precision improves, but manufacturing time increases

Engineering Contradiction:

Improvealignment precisionVSAvoidbonding speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The magnetic pads are formed on the bonding surfaces during the substrate fabrication process before the actual bonding operation. This preliminary preparation ensures that alignment references and magnetic bonding interfaces are already in place, enabling rapid self-aligned bonding without requiring additional alignment steps during assembly, thus maintaining high productivity.

Inventive Principle:

Principle #10Preliminary 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

This approach improves alignment precision and reliability of semiconductor package structures, increasing the yield and performance of hybrid bonding in advanced packaging technologies by ensuring accurate and efficient die-on-wafer bonding.

Implementation Method 1

magnetic pads on semiconductor wafers for self-aligned bonding, where ferromagnetic materials like iron, cobalt, or nickel are magnetized to attract and align the wafers during bonding

Methodology Applied

Scientific EffectMagnetic bonding: Magnetism

Implementation Method 2

ferromagnetic materials like iron, cobalt, or nickel are magnetized to attract and align the wafers during bonding

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentUS10157885B2Package structure having magnetic bonding between substrates

Publication Date: 2018.12.18 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A package structure and method for forming the same are provided. The package structure includes a first die, and the first die includes a first magnetic pad formed over a first substrate. The package structure includes a second die, and the second die includes a second magnetic pad formed over a second substrate. The package structure also includes a hybrid bonding structure formed between the first die and the second die of the second wafer. The hybrid bonding structure includes a magnetic bonding structure which is made of the first magnetic pad and the second magnetic layer.