Inert Gas Soak Chamber for IC Testing Oxidation

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Solution Overview

Problem

High contact resistance between testing pins and leads of integrated circuit (IC) devices during testing leads to false failures and increased costs due to retesting, necessitating improved first pass testing yield and reduced testing costs.

Innovation Solution

An IC device testing system that includes a soak chamber for soaking the IC device in high-purity inert gas, a test chamber with heated contact pins, and a transfer zone, where the IC device is transferred from the soak chamber to the test chamber to reduce oxidation and contact resistance by using inert gas at high temperature and purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If IC devices are tested in conventional air environment, then testing process is simple, but contact resistance increases due to oxidation on leads

Engineering Contradiction:

Improvecontact resistanceVSAvoidtesting system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a inert gas environment (nitrogen or other inert gases) in both the soak chamber and test chamber to prevent oxidation on IC device leads. The inert atmosphere is maintained throughout the testing process, including during the soaking period and actual testing, thereby reducing contact resistance and improving first-pass yield without significantly increasing system complexity.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent introduces a soak chamber that soaks IC devices in inert gas before testing to pre-prevent oxidation on the leads. This preliminary action in the soak chamber prepares the device by creating an oxidation-free surface before the actual testing occurs in the test chamber, thereby improving contact resistance.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If high-purity inert gas is used to reduce oxidation, then contact resistance decreases, but gas consumption and cost increase

Engineering Contradiction:

Improvetesting yieldVSAvoidinert gas consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent maintains continuous inert gas flow through both the soak chamber and test chamber throughout the entire testing process. This continuous action ensures that oxidation is prevented at all times, from soaking through testing, maximizing first-pass yield while optimizing gas usage efficiency.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent specifies using high-purity inert gas (99.9% or higher purity nitrogen or other inert gases) to maximize oxidation prevention effectiveness. This parameter change in gas purity directly reduces contact resistance and improves testing yield, while the system design optimizes the balance between purity level and gas consumption.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If oxidation on leads is prevented using inert gas, then first pass testing yield improves, but retesting costs increase

Engineering Contradiction:

Improvefirst pass testing yieldVSAvoidtesting equipment capacity

Core Design Contradiction:

ProductivityVSUse of energy by stationary object

Solution Approach 1:

By maintaining inert atmosphere throughout the testing process, the patent prevents oxidation that causes false failures, thereby improving first-pass yield and reducing the need for retesting and additional equipment capacity.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The soak chamber performs preliminary oxidation prevention before testing, ensuring leads are oxidation-free before contact pins make contact. This preliminary action increases first-pass yield by preventing contact resistance issues before they occur during testing.

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

The system effectively reduces oxidation on IC leads, thereby lowering contact resistance and improving the first pass testing yield, reducing retesting needs and associated costs.

Implementation Method 1

The presence of an oxidized layer on the leads of an integrated circuit (IC) device may lead to a high contact resistance during testing. Tin (Sn) plating on the leads may become oxidized prior to testing to form Tin oxide (SnO). By introducing an inert gas at high purity and high temperature prior to and during testing, oxidation is reduced and further oxidation is prevented.

Methodology Applied

Scientific EffectOxidation prevention: Oxidation

Implementation Method 2

By reducing the oxidation layer, the contact resistance during testing is reduced, thereby improving the first pass testing yield and reducing testing costs.

Methodology Applied

Scientific EffectThermal heating: Heating

Implementation Method 3

The soak chamber soaks an integrated circuit (IC) device in the inert gas prior to testing.

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10473712B2Integrated circuit device testing in an inert gas

Publication Date: 2019.11.12 INFINEON TECHNOLOGIES AG

AI summary

A system includes an inert gas supply, a soak chamber, a test chamber, a transfer zone, and a heater. The soak chamber soaks an integrated circuit (IC) device in the inert gas prior to testing. The test chamber includes contact pins for testing the IC device in the inert gas by contacting the contact pins to leads of the IC device. The transfer zone is to transfer the IC device from the soak chamber to the test chamber. The heater heats the inert gas supplied to the soak chamber and the test chamber.