QUALITY
ASSURANCE
1.
VIEWS
ON
QUALITY
AND
RELIABILITY deSign, device design, layout design, etc. There-
fore, as long as standardized proceSSing and
Basic views on
quality at Hitachi are
to
meet
the
materials are used
the
reliability risk is extremely
individual
uers' required quality level and maintain a small even in
the
case of
new
development
general quality level equal
to
or above
that
of
the
devices,
with
the exception of special require-
general market. The quality required,by
the
user may ments imposed by functional needs.
be specified by contract, or may be indefinite.
In either
case, efforts are made
to
assure reliable performance
in
actual operating circumstances. Quality control
during
the
manufacturing process, and quality aware-
ness from design through production lead
to
product
quality and customer satisfaction.
Our
quality assur-
ance technique consists basically of
the
following
steps:
(1)
Build
in
reliability at
the
design stage of
new
product development.
(2) Build in
quality
at all steps in
the
manufacturing
process.
(3) Execute stringent inspection and
reliability con-
firmation of final products.
(4) Enhance
quality levels through field data feed
back.
(5) Cooperate
with
research laboratories for higher
quality and reliability.
With
the
views and methods mentioned above,
utmost efforts are made to meet users' requirements.
2.
RELIABILITY DESIGN OF
SEMICONDUCTOR DEVICES
2.1 Reliability Targets
The reliability target is an
important
factor
in
sales,
manufacturing, performance, and price.
It
is not ade-
quate to set a reliability target based on a single set of
common test conditions. The
reliability target is set
based on many factors:
(1) End use
of
semiconductor device.
(2) End use
of
equipment in
which
device is used.
(3) Device manufacturing process.
(4) End user manufacturing techniques.
(5)
Quality control and screening test methods.
(6)
Reliability target of system.
2.2
Reliability Design
The
following
steps are taken
to
meet
the
reliability
targets:
(1) Design Standardization
As
for
design rules, critical items pertaining to
quality and reliability are always studied at circuit
19
(2) Device Design
It is important for
the
device deSign to consider
total balance of process, structure, circuit, and
layout design, especially in
the
case where
new
processes
and/or
new
materials are employed.
Rigorous teChnical studies are conducted prior to
device
development.
(3) Reliability Evaluation by Functional
Test
Functional Testing is a useful method for design
and process reliability evaluation of IC's and LSI
devices
which
have complicated functions.
The objectives of
Functional Test are:
• Determining the fundamental failure mode.
• Analysis of relation between failure mode and
manufacturing process.
• AnalysiS of failure mechanism.
• Establishment of
QC
points in manufacturing
process.
2.3
Design Review
Design Review is an organized method to confirm
that
a design satisfies
the
performance required and
meets design specifications.
In addition, design review
helps to insure quality and reliability of the finished
products.
At
Hitachi, design review is performed from
the
planning stage
to
production for
new
products,
and
also
for
design changes on existing products.
Items discussed and considered at design review are:
(1) Description of the products based
on
design
documents.
(2) From the standpoint of each participant, design
documents are studied, and for points needing
clarification,
further
investigation
will
be
carried
out.
(3) Specify
quality control and test methods based on
design documents and drawings.
(4) Check process and
ability of manufacturing line to
achieve design
goal.
(5) Preparation for production.
(6)
Planning and execution of sub-programs for
design changes proposed by
individual specialists,
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