Test Strategies to Enable NPD Revenue Plans
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Freedom from
Project Surprises Newsletter - Issue #41
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September 2008 |
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How
do you view the role of test development in your New Product
Development plans? Test spans three major segments that include silicon
validation, silicon characterization and production test. Activities in
each of the segments increase the understanding of different aspects of
a chip and may involve different people, different equipment and
different objectives. In all three cases test considerations must be
part of the early planning process, commencing at the engineering
requirements phase. This month's newsletter topic on the subject of
test was a suggestion from one of our readers. As always, I appreciate
hearing from readers to steer me in the direction of maximizing the
value of this monthly email for each of you.
Jeff Jorvig, NPD Process Consultant
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News of Interest
- Mind Mapping
- If you're looking for a way to migrate ideas and concepts to the next
level, give mind mapping a try. I use them all the time to map out
paths to possible solutions. Mind
Meister is the one I use.
- Check out this web
based solution to managing your NPD/NPI process here.
- Check out our quick
start instant downloads for managing design
projects.
Leadership Quote of the month:
"Excellence is not an act,
it is a habit."
--Aristotle |
Testing - From Product Concept to
Production
When
thinking about testing for a new product what first comes to mind? Is
it manufacturing, quality or design validation? If you're a designer I
believe you would be most interested in functional validation. Someone
from the product management organization would probably consider
quality or manufacturing first. Tests to cover this broad scope of
validation needs carry similar levels of importance, yet have vastly
different approaches.
Manufacturing test focuses on time,
defects and electrical requirements; quality testing concentrates on
characterizing design margin and reliability; design validation directs
attention to functionality and parametric data - "does it meet the
customers application?" All three testing categories play a
considerable role in a high quality product, however they can place
very different demands on the silicon content necessary to fully
support them.
When defining a new product are you including all
three of the test category types as you develop engineering
specifications? If not, then your product is left open to higher
product costs, or quality and yield issues once you get into
production. I find it best that all silicon expectations for testing
reside in the engineering specification, further reinforcing the
thought process about silicon requirements in support of testing. This
also emphasizes test strategies early in the development process, when
something can still be done about it.
 Make
sure you have a process in place for creating a comprehensive test plan
that includes all three testing categories. Complete that strategy for
testing during the product definition phase and include any silicon
content expectations in support of production testing, validation and
characterization. Bear in mind that the test strategy is a
multi-disciplined effort. Design knows what needs to be validated and
characterized while test and product engineering knows the hardware and
software capabilities of the testing environment and will bring the
required focus on production test costs to the plan. The output of the
test strategy should directly drive the silicon requirements to support
those tests. Please see the diagram above for a proposed NPD
requirements flow that meets the objective of early test definition to
drive the silicon expectations in support of those tests.
The
days of testing as an afterthought should be long gone in the
development organizations of today. Involve test early, involve test in
product definition (test modes) and listen to the test and product
engineer's inputs on testability concerns. In today's environment there
will be no acceptance of a wasted silicon spin to support testing after
the fact, nor will there be any tolerance of quality issues due to
silicon characterization or validation limitations. Think through
testing up front to prevent an inadequacy in silicon validation
capabilities from becoming a surprise, just as you are eagerly
anticipating a production ramp.
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The
Role of the Three Silicon Testing Categories
Proper validation of silicon in support of a production
worthy product involves three major categories of testing requirements.
 These
test types include manufacturing, characterization and functional
validation. See the table to the right for an overview of these test
types. Below I will expand upon the requirements of each one of these
three essential testing philosophies.
Functional Validation
This
type of testing us usually done on a low volume engineering type setup
and concentrates on verifying that the silicon meets the original
requirements, both electrical as well as functional. There may be
specific silicon test modes necessary for functional validation but
usually the characterization and manufacturing needs will cover the
validation activities as well. The design engineer needs to be highly
involved in defining the functional validation requirements, the test
fixture definition and the actual validation activities. Remove any
barriers (or excuses) that would keep the design engineer(s) away from
the bench during the silicon validation activities. Their required
participation will provide a minimized path to production and enable
the designer's essential "real world" silicon learning cycle.
Manufacturing
Once
a product is ready for manufacturing the test focus moves from
functional verification to the identification of manufacturing defects.
Once functionality has been verified via functional validation testing,
a defect is the only means that functionality would be altered, hence
defects become the primary objective of production testing for
manufacturing. Test costs and test coverage to maximize defect exposure
along with parametric validation are the principal motivators in
decisions about manufacturing test. In digital land this is what
motivates an emphasis on scan, which has some very specific silicon
requirements to support this mode. In analog land the primary
requirement will be visibility and stimulus of internal analog
sub-systems, usually accomplished via test modes to mux key internal
signals to external pins.
Characterization
This
type of testing involves the ability to margin the design by varying
FAB processes, supplies, frequencies and signal levels. For analog,
this often requires visibility to internal signals, supplies,
references and so on. For digital, the silicon support is often the
same as the production test requirement of having a scan capability to
inject and view the internal data. The process variance is typically
accomplished via process corner splits within a given lot. There may
also be some specific requirements necessary in support of ESD and/or
latch-up testing that should also be considered.
Again, all
three of these testing families are essential for a product prior to
release to production. Do these well by facilitating an early plan to
define the silicon content necessary for all three, thus removing
another layer of potential surprises in your product release plans.
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| How we
can Help
"Providing solutions to the hidden, behind the scenes project
roadblocks that quietly steal early revenue opportunity"
- Template development for engineering specifications. Includes
the development process phase requirements as well as the technical,
verification and test
information, all in one stand alone document - great for IP sharing too.
- Execution
Challenges? - Are you
confident enough in your leadership to entertain an outside assessment
of
the barriers to your teams ideal level of project execution? Discovery Survey is an economical
solution to providing that external view.
- Business
process modifications to optimize inputs and outputs from New
Product Development teams.
- NPD team work flow assessment and bottleneck
mitigation to get your team on track for meeting project commitments.
- NPD team workshop to improve planning, execution and monitoring skills.
- Web based NPD workflow management.
- Ready made downloads:
schedule, checklist, analog design guide.
- Increase design management bandwidth via Virtual Design Manager.
- Full listing of common services here.
Contact us today via email, 480-895-0478 or
877-895-0478 |
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Feedback
To increase the value of this newsletter for you I would like
to hear your comments.
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newsletter?
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the future?
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Please email me here with any questions,
comments or suggestions that will help me better serve my readers. I
would enjoy hearing from you.
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