DLTS Measurement Apparatus Maintenance for Accuracy
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Solution Overview
Problem
The DLTS measurement method experiences inaccuracies due to chronological changes and differences in the sample stage and wiring of the measurement apparatus, leading to unreliable process control and quality monitoring in epitaxial growth furnaces and semiconductor wafers.
Innovation Solution
A method for managing the DLTS measurement apparatus involves determining if measurement values are within a set allowable range and performing maintenance, including exchanging or repairing the sample stage, first wiring, and second wiring, with conductive covering film formation on the sample stage and wiring tips using metals like Au, Ag, or Pt to prevent measurement inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DLTS measurement is performed using conventional apparatus without maintenance, then measurement can be conducted continuously, but measurement accuracy deteriorates due to chronological changes in sample stage and wiring
Solution Approach 1:
The patent applies preliminary action by establishing maintenance schedules and procedures before measurement accuracy deteriorates. The control computer monitors measurement values over time and triggers maintenance actions (exchanging sample stage, wiring, or probe needles) before the apparatus components degrade to a point where measurements become unreliable. This proactive approach ensures measurement accuracy is maintained by addressing chronological changes in the sample stage and wiring before they significantly impact measurement reliability.
2Measurement precision
If measurement apparatus components are frequently exchanged or maintained, then measurement accuracy is maintained, but device complexity and maintenance cost increase
Solution Approach 1:
The patent implements feedback by using the control computer to continuously monitor measurement values and compare them against reference ranges. When measurement values fall outside the acceptable range, the system automatically generates maintenance alerts and determines which components (sample stage, wiring, or probe needles) require replacement. This feedback mechanism optimizes maintenance frequency by performing exchanges only when necessary, maintaining measurement accuracy while avoiding unnecessary maintenance actions that would increase device complexity and costs.
3Reliability
If probe needles are exchanged based on resistance values, then electrical contact reliability is improved, but measurement precision may be affected by improper exchange timing
Solution Approach 1:
The patent applies self-service by enabling the measurement apparatus to automatically monitor its own component conditions and trigger maintenance actions. The control computer continuously measures electrical parameters including probe needle resistance and compares them against predetermined thresholds. When resistance values indicate degradation, the system automatically determines that probe needle exchange is needed, ensuring electrical contact reliability is maintained while preventing measurement precision deterioration from improper exchange timing. The system serves itself by detecting and responding to its own degradation without external intervention.
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 enhances measurement accuracy and reliability by reducing the influence of the measurement apparatus on the DLTS method results, allowing for precise evaluation of metal contamination and crystal defects in semiconductor samples.
Implementation Method 1
performing maintenance, including exchanging or repairing the sample stage, first wiring, and second wiring, with conductive covering film formation on the sample stage and wiring tips using metals like Au, Ag, or Pt to prevent measurement inaccuracies
Data Source
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Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
An aspect of the present invention relates to a method of managing a DLTS measurement apparatus, wherein the DLTS measurement apparatus comprises a sample stage which has a measurement target sample placement surface and on which a measurement target sample having a semiconductor junction on one surface of a semiconductor sample and an ohmic layer on the other surface is placed in which the ohmic layer and the measurement target sample placement surface face each other; a first wiring having a tip contacting or being to contact with the measurement target sample; and a second wiring having a tip contacting or being to contact with the sample stage, and the method comprising determining whether or not a measurement value measured by the DLTS measurement apparatus is in a preliminarily set allowable range; and performing maintenance processing of exchanging or repairing at least one of a whole or a part of the sample stage, a whole or a part of the first wiring, and a whole or a part of the second wiring, in a case where the measurement value is outside the preliminarily set allowable range as a result of the determination.