Quality and Reliability Assurance / Handling Precautions
Quality And Reliability Assurance / Handling Precautions
In recent years, technical revolutions have become almost a daily occurrence in the
electronics industry. This is accompanied by the increasing application of semiconductors in
both the consumer and industrial sectors, and demands for higher quality and higher
reliability.
Toshiba is making every effort to improve both quality and reliability with the following
quality control system which incorporates product design, quality assurance for parts and
materials received, manufacturing process quality assurance, shipping quality and
reliability assurance, and quality after-service based on user demands and market survey
data.
1 Quality And Reliability Assurance
1.1
Quality Assurance
Trying to sense the customer’s needs, we do our best to incorporate the quality and
reliability required by the customer into the design, while considering the safety
and PL (Product Liability) of the products.
Quality and reliability evaluation are performed on the developed products
according to the Toshiba’s reliability test standard which is prepared in conformity
with JIS, EIAJ, MIL, etc., thereby certifying the design. The parts and materials
are standardized through the engineering department and the quality assurance
department. After the design is accepted, standardization is performed by the
engineering department on the parts and materials, process plan, and inspection
plan. Engineering Institution of Works (EW) is then established on the working
detail. The quality and reliability evaluation are performed on the mass-produced
products on an experimental basis.
In the mass production, the production department has control of the
manufacturing process, the environment and facility, and the quality assurance
department. Quality assurance performs incoming inspection of parts and
materials, modification control, instrument control, periodical reliability test and
line audit. The production technology divisions also participate in process
improvement, automatization, etc.
Education and training for quality and reliability, are given to new workers,
inspectors, engineers and small groups (QC/ZD movement). In shipping the
finished products, a lot quality assurance test is performed by the quality assurance
department. We then commence preparation of specifications meeting pre-arranged
quality and reliability standards and the inspection and reports on discrepant
products “quick action” as the motto. Figure 1 shows the quality assurance system
of semiconductor.
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2002-02-20
Quality and Reliability Assurance / Handling Precautions
1.2
Quality Assurance Level of Semiconductor Products
Lot Quality Assurance (AQL display: in accordance with ANSI Z 1.4-1993)
Table 1
Item
Electrical Characteristics
Appearance
Serious Defect
Minor Defect
AQL
0.15%
0.15%
0.25%
Table 1 shows the lot quality
assurance level, which is complied
with the sampling inspection
method (AGL) of MIL-STD-105E.
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2002-02-20
Quality and Reliability Assurance / Handling Precautions
Department
Step
Planning
Market /
Customers
Marketing
Application
Engineering
Manufacturing
Engineering
QA
Manufacturing
Production
Control
Subcontractors
DR/AT
Control System
Check Sheets
Meetings
Development CS Development
Planning
Meeting
Market Research
Review of
Specifications
Determine Development Plan
Determine Specification
Product Design
Design Review, Safety and PL Check
Parts and
Materials
Approval
Trial Production of Developed Product,
Evaluation of Characteristics
Q & R Evaluation of Developed Product
Design Approval
DAT DAT Execution
Plan CS
DAT Execution
Meeting
DR
Development CS Design Planning
Meeting
Development
Design
Trial Run
Production
Standardization (Parts & Materials,
Process Plan, Inspection Plan)
Qualification
Preparation
of Parts and of Engineering
Materials
Instructions
Trial Run
Production
Q & R Evaluation of Trial Run Production
Approval of Production
Quality
Transfer to Full Production
QAT QAT Execution
Plan CS
DAT Execution
Meeting
QAT Execution
Meeting
QAT Review
Meeting
Transfer
Meeting
Full
Production
*1
Full Production
*2
*3
Subcontracting
Control of Changes
Q & R Evaluation of
Production Product
Approval of Production
Product
QA Meeting
Confirmation
of Shipped
Quality
Delivery
Quality, Engineering and Complaint
Service
Failure
Analysis
Complaint
Complaint
Handling
Shipment
PAT PAT Execution
Plan CS
PAT Execution
Meeting
PAT Review
Meeting
*4
DR:
DAT:
QAT:
CS:
Design Review
Design Approval Test
Quality Approval Test
Check Sheet
*1
*2
*3
*4
Improvement of Manufacturing Technology
Promotion of Automatization
Inspection of Incoming Parts
Line Audit
Reliability Test
Measurement Control
Quality Training & Education
Manufacturing Control
Environmental Control
Facility Control
Assurance of Quality, Cost & Delivery
Control of Delivery and Quantity
Figure 1
Quality Assurance (QA) System of Procedural Flow
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2002-02-20
Quality and Reliability Assurance / Handling Precautions
1.3
Reliability of Microcontrollers
For microcontroller products, reliability can be estimated within the following
temperature range.
Tj = 0°C to 85°C
Tj (junction temperature) can be calculated using the following formula:
Tj = Ta + Q
× θja
Ta: Operating environment temperature for the product
[°C]
The operating environment temperature is the temperature of the
surrounding environment. The thermal effects of the operation of the
product are not taken into account.
Q: Average power consumption of the product
[W]
θ
ja: Thermal resistance of the package
[°C
/ W]
Note 1: When operating the device outside the range Tj = 0°C to 85°C for
extended periods, please contact your nearest Toshiba office or
authorized Toshiba dealer.
Note 2: For details of the value of
θ
ja, please contact your nearest Toshiba office
or authorized Toshiba dealer.
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2002-02-20
Quality and Reliability Assurance / Handling Precautions
2 Handling Precautions for Microcontrollers
2.1
Mounting Precautions
Plastics have basically porous feature. When a chip (especially an SMD which has a thin
plastic surface) is heated in a state of moisturized and is soldered by the reflow soldering
method, moisture is vaporized as the temperature rises to cause a package expanded. Or a
borderd surface between a lead frame and a plastic material is peeled off to cause a crack.
These bring serious troubles on reliability.
In order to prevent hygroscopity or enable high heat treatment after absorbing moisture,
Toshiba uses a dampproof packing and/or a heat proof tray.
(1) Recommended Methods of Soldering for Flat Packages
•
Table 2.1 lists the recommended method of soldering flat packages. If you have
any question or request, please refer to “IC PACKAGE MANUAL” or contact
your local offices.
•
For overall heating method, recommended mounting methods and
conditions after opening the pack differ depending on products to be
used. See Table 2.2 and 2.3 for the details.
For locally heating a lead part, soldering iron method is
recommended. For other localized heating methods, refer to “IC
PACKAGE MANUAL” or contact your Toshiba local offices.
•
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2002-02-20
