Hybrid Bonding Structure for Void-Free Copper-Dielectric Joining

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Solution Overview

Problem

The formation of voids during copper/dielectric hybrid bonding in semiconductor devices due to moisture interference, particularly at the oxide bonding stage, leads to inconsistencies and defects in the finished semiconductor device.

Innovation Solution

The use of a heatable mounting stage and bond head with a collet to apply vacuum and controlled temperature to deform substrates into a convex shape, combined with silicon carbon nitride layers to form a hermetic seal, preventing moisture from affecting the bonding surface and using isothermal heating to remove adsorbed moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper/dielectric hybrid bonding is performed at standard conditions, then bonding speed is maintained, but voids form due to moisture interference

Engineering Contradiction:

Improvebonding qualityVSAvoidbonding speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The bonding surfaces are pre-heated to elevated temperatures (e.g., 150°C to 250°C) before the actual bonding process to remove adsorbed moisture and prevent void formation during bonding, ensuring high reliability without sacrificing productivity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The bonding temperature is increased from standard room temperature to elevated temperatures (150°C-250°C) to eliminate moisture interference and prevent void formation, achieving both high reliability and maintained productivity

Inventive Principle:

Principle #35Parameter changes

2Reliability

If vacuum is applied to deform substrates into convex shape, then moisture removal is improved, but device complexity increases

Engineering Contradiction:

Improvevoid formation controlVSAvoidbonding apparatus complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The substrate is deformed into a convex shape during bonding to create a dome-like structure that facilitates moisture removal from the bonding interface, improving void formation control through geometric modification

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

Vacuum pressure is applied to the substrate to deform it into a convex shape during bonding, using pneumatic principles to remove moisture from the bonding interface and prevent void formation

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Reliability

If isothermal heating is used to remove adsorbed moisture, then bonding reliability improves, but energy consumption increases

Engineering Contradiction:

Improvebonding consistencyVSAvoidheating energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The bonding temperature is precisely controlled and maintained at a specific elevated temperature range (150°C-250°C) to optimally remove adsorbed moisture while minimizing energy consumption, achieving both high reliability and energy efficiency

Inventive Principle:

Principle #35Parameter changes

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 method reduces void formation, enabling high-density IO connections and improved 3D integration by eliminating moisture-induced defects, allowing for finer pitch and more reliable semiconductor device manufacturing.

Implementation Method 1

a heatable bond head configured to have a vacuum applied thereto to deformably accommodate the second semiconductor substrate and the second stack of semiconductor materials against the collet

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

isothermally heating at least one of the bond head or the stage to control a thermal distortion between the silicon die device on the upper substrate and the bottom substrate

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

combined with silicon carbon nitride layers to form a hermetic seal, preventing moisture from affecting the bonding surface

Methodology Applied

Scientific EffectHermetic seal:

Implementation Method 4

Cu/dielectric bonding is through non-melting Cu diffusion bonding

Methodology Applied

Scientific EffectDiffusion bonding: Diffusion Welding

Data Source

PatentUS12456709B2Structures and processes for void-free hybrid bonding

Publication Date: 2025.10.28 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

An apparatus for bonding a first substrate to a second substrate includes a heatable mounting stage configured to accommodate a first semiconductor substrate on an upward-facing surface and a first stack of semiconductor materials on the first semiconductor substrate; a heatable bond head configured to accommodate a second semiconductor substrate on a downward-facing surface and a second stack of semiconductor materials on the second semiconductor substrate; and a collet disposed on the downward-facing surface of the heatable bond head and configured to receive the second semiconductor substrate and the second stack of semiconductor materials. The heatable bond head is configured to have a vacuum applied thereto to deformably accommodate the second semiconductor substrate and the second stack of semiconductor materials against the collet. The heatable bond head is configured to be pressed against the heatable mounting stage to bond the semiconductor materials.