Semiconductor Termination Structure Charge Removal

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Solution Overview

Problem

Semiconductor devices with charged insulating or semi-insulating films in the termination structure exhibit increased leakage current and unstable dielectric strength during testing, necessitating a method to remove charge from these films.

Innovation Solution

A method involving a charge removal step using various devices such as resistor devices, grounding devices, or voltage apply devices to depolarize the top surface layer of the termination structure, allowing for accurate dielectric strength testing without delay times, thereby reducing inspection time and preventing thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dielectric strength testing is performed on semiconductor devices with charged insulating films in the termination structure, then the testing can be conducted, but the measurements exhibit increased leakage current and unstable dielectric strength

Engineering Contradiction:

Improvestability of dielectric strength measurementVSAvoidaccuracy of dielectric strength measurement

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing a charge removal step before dielectric strength testing. The method includes: (1) applying a first voltage to remove charge from the insulating film of the termination structure, (2) then performing dielectric strength testing. This preliminary charge removal eliminates the source of measurement instability and leakage current, ensuring accurate and reliable measurements from the outset.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If charge removal is performed using conventional methods with delay times, then charge can be removed from the insulating film, but inspection time increases

Engineering Contradiction:

Improvecharge removal effectivenessVSAvoidinspection time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies parameter changes by optimizing the voltage application parameters for charge removal. The method specifies applying a first voltage within a predetermined range (e.g., 50-200V for a certain duration) to efficiently remove charge from the insulating film. By carefully controlling voltage magnitude and application time, the patent achieves effective charge removal while minimizing the charge removal step duration, thus reducing overall inspection time while maintaining reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements continuity of useful action by integrating the charge removal step directly into the testing workflow without unnecessary interruptions or extended delay times. The charge removal voltage is applied continuously for a optimized duration, and the process flows seamlessly into the dielectric strength testing phase, eliminating wasted time while ensuring complete charge removal effectiveness.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If repeated testing is performed on semiconductor devices, then comprehensive testing can be conducted, but thermal damage may occur due to accumulated heat

Engineering Contradiction:

Improvecompleteness of testingVSAvoidthermal damage risk

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent applies preliminary action by performing charge removal before dielectric strength testing, which eliminates the need for repeated testing attempts due to measurement failures. By ensuring the insulating film is properly decharged beforehand, the first testing run provides accurate results, avoiding the need for retesting that would generate additional heat and increase thermal damage risk.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies the skipping principle by rushing through the charge removal process with optimized voltage parameters that achieve complete charge removal in minimal time. This efficient approach allows the testing to proceed immediately without delays, reducing the total number of testing cycles required and thereby minimizing cumulative heat generation from repeated testing operations.

Inventive Principle:

Principle #21Skipping (Rushing through)

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

Effectively removes charge from the top surface layer, stabilizing dielectric strength measurements and reducing inspection time by integrating a charge removal step after initial testing, ensuring reliable and efficient semiconductor device testing.

Implementation Method 1

the insulating film of the termination structure is charged by polarization

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 2

removing charge from the top surface layer of the termination structure

Methodology Applied

Scientific EffectElectrostatics: Electrostatics

Data Source

PatentUS9401314B2Method of testing semiconductor device

Publication Date: 2016.07.26 MITSUBISHI ELECTRIC CORP

AI summary

A method of testing a semiconductor device having a substrate in and on which a cell structure and a termination structure are formed, the cell structure having a main current flowing therethrough, the termination structure surrounding the cell structure, the method includes a first test step of testing dielectric strength of the semiconductor device, a charge removal step of, after the first test step, removing charge from a top surface layer of the termination structure, the top surface layer being located on the substrate and formed of an insulating film or a semi-insulating film, and a second test step of, after the charge removal step, testing dielectric strength of the semiconductor device.