Gold Brazed Bonding Structure for Susceptor Terminal

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Solution Overview

Problem

Existing bonding structures for semiconductor wafer susceptors, which connect electrodes in ceramic members to power supply members, face issues with high temperature durability and mechanical strength due to the use of Au-Ni solder alloys and low-melting-point aluminum brazing, leading to vulnerability and reduced bonding strength.

Innovation Solution

A bonding structure using a ceramic member made of aluminum nitride with a molybdenum terminal and connecting member, bonded via a gold-only brazed bond layer, incorporating clearances and braze pool spaces to enhance thermal expansion matching and mechanical stability, and employing a gold brazed bond layer with specific thickness and geometry to prevent intermetallic compound formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Au-Ni solder alloy is used for brazed bond layer, then electrical connection is achieved, but bonding strength decreases and vulnerability increases

Engineering Contradiction:

Improvebonding strengthVSAvoidbonding strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent extracts and removes the problematic Ni component from the brazed bond layer, using Au-only material instead. This eliminates the intermetallic compound formation issue while maintaining electrical conductivity and bonding strength requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the material composition parameter of the brazed bond layer from Au-Ni alloy to pure Au, and optimizes the thickness parameter to 3-10 μm. This parameter change prevents vulnerable intermetallic compound formation while ensuring adequate bonding strength and electrical connection.

Inventive Principle:

Principle #35Parameter changes

2Strength

If thicker brazing material layer is used, then bonding strength is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvebonding strengthVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent optimizes the brazing material layer thickness to a specific range of 3-10 μm. This parameter optimization achieves adequate bonding strength without requiring excessively thick layers, thereby simplifying manufacturing processes and reducing material costs.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If screw connection is used for power supplying member, then electrical connection is achieved, but mechanical load on bonding portion increases causing breakage

Engineering Contradiction:

Improveelectrical connectionVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent segments the connection function into two separate mechanisms: the brazed bond layer provides mechanical bonding and electrical connection, while the screw connection is used only for electrical connection and adjustment. This segmentation prevents mechanical load from the screw from compromising the bonding portion.

Inventive Principle:

Principle #1Segmentation

4Reliability

If aluminum brazing is used for ceramic member fixation, then bonding is achieved, but bonding strength decreases at high temperatures

Engineering Contradiction:

Improvebonding reliabilityVSAvoidhigh temperature durability

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent changes the brazing material from low-melting-point aluminum to high-melting-point pure gold. This parameter change in material composition enables the bonding structure to maintain adequate bonding strength at high temperatures up to 400°C and above, where aluminum brazing would fail.

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

The solution provides a robust and durable bonding structure that maintains high bonding strength and mechanical stability under extreme temperature cycles and mechanical loads, preventing breakage and ensuring reliable electrical connection.

Implementation Method 1

a brazed bond layer consisting of gold (Au) only; and a connecting member inserted in the hole, bonded to the terminal via the brazed bond layer

Methodology Applied

Scientific EffectBrazing: Brazing

Implementation Method 2

a ceramic member made of aluminum nitride and including a hole

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS8193629B2Bonding structure for a terminal of a susceptor of a semiconductor device manufacturing apparatus

Publication Date: 2012.06.05 NGK INSULATORS LTD

AI summary

A bonding structure including: a ceramic member made of aluminum nitride and including a hole; a terminal embedded in the ceramic member, exposed to a bottom surface of the hole, and made of molybdenum; a brazed bond layer consisting of gold (Au) only; and a connecting member inserted in the hole, bonded to the terminal via the brazed bond layer, and made of molybdenum.