Wafer Bonding System Pneumatic Force Alignment

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Solution Overview

Problem

Existing wafer bonding technologies face issues with misalignment and non-uniform heat application due to mechanical shear forces and poor thermal coupling, leading to suboptimal bonding quality.

Innovation Solution

A wafer bonding system utilizing a pneumatic force created by a pressure differential between a surrounding high-pressure environment and a lower pressure between the wafers, combined with non-contact gaseous thermal paths for heating, which minimizes mechanical stress and ensures uniform heat distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If mechanical elements (hydraulic pistons) apply contact pressure directly onto wafer clamping elements, then bonding force is achieved, but shear forces cause misalignment of wafers

Engineering Contradiction:

Improvebonding forceVSAvoidwafer alignment

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical contact pressure system (hydraulic pistons directly contacting clamping elements) with a pneumatic system. Gas pressure is applied to the wafer clamp assembly, creating bonding force through pneumatic pressure differential rather than direct mechanical contact. This eliminates shear forces from mechanical elements while maintaining the necessary bonding force, thereby preserving wafer alignment precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs pneumatic pressure differential to apply bonding force. A first pressure (higher) surrounds the wafer clamp assembly while a second pressure (lower, e.g., vacuum) is maintained between the wafers. This pressure differential creates the bonding force without mechanical contact, eliminating the shear forces that caused misalignment in previous mechanical systems.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Temperature

If heating elements are integrated within mechanical elements, then direct thermal path is achieved, but vacuum environment creates poor thermal coupling and non-uniform heat distribution

Engineering Contradiction:

Improveheat applicationVSAvoidheat uniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical thermal conduction path (heating elements integrated within mechanical pistons) with a non-contact thermal path. Heating elements are positioned adjacent to the wafer clamp assembly without direct mechanical contact, transferring heat through radiation or convection in the gas-filled environment. This eliminates the poor thermal coupling caused by vacuum while achieving uniform heat distribution across the wafer surfaces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stress or pressure

If mechanical elements contact wafer clamping elements, then pressure is applied, but adverse stresses cause wafer misalignment

Engineering Contradiction:

Improvecontact pressureVSAvoidwafer alignment

Core Design Contradiction:

Stress or pressureVSManufacturing precision

Solution Approach 1:

The patent substitutes mechanical contact pressure application with pneumatic pressure differential. Instead of mechanical elements physically contacting and stressing the wafer clamping elements, gas pressure is used to transmit force through the clamp assembly. This pneumatic approach applies the necessary contact pressure for bonding while distributing stress uniformly without creating adverse localized stresses that would cause misalignment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 reduces wafer misalignment and achieves consistent, controlled heating, allowing for optimized pressure and heating functions, resulting in improved bond quality between semiconductor wafers.

Implementation Method 1

a pneumatic force created by a pressure differential between a first pressure surrounding the two wafers and a second pressure, which is less than the first pressure, maintained between the two wafers

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

The wafers are heated via a non-contact, gaseous interface, thermal path between heating elements and the wafers

Methodology Applied

Scientific EffectThermal conduction through gas: Conduction (thermal)

Data Source

PatentUS10121760B2Wafer bonding system and method

Publication Date: 2018.11.06 SCREEN HOLDINGS CO LTD

AI summary

A wafer bonding system and method using a combination of heat and a pneumatic force to bond two wafers held together in alignment. The wafers are heated via a non-contact, gaseous interface, thermal path between heating elements and the wafers. The pneumatic force is created by a pressure differential between a first pressure surrounding the two wafers and a second pressure, which is less than the first pressure, maintained between the two wafers.