Annual report 2000 - Europractice
Annual report 2000 - Europractice
Annual report 2000 - Europractice
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Low cost IC prototyping<br />
The cost of producing a new ASIC<br />
for a dedicated application within a<br />
small market can be high, if directly<br />
produced by a commercial foundry.<br />
This is largely due to the<br />
4<br />
NRE (Non-Recurring Engineering)<br />
overheads associated with design,<br />
manufacturing and test.<br />
EUROPRACTICE has reduced the<br />
NRE, especially for ASIC prototyping,<br />
by two techniques:<br />
(i) Multi Project Wafer Runs or<br />
(ii) Multi Level Masks.<br />
Multi Project Wafer Runs<br />
By combining several designs from<br />
different customers onto one mask<br />
set and prototype run, known as<br />
Multi Project Wafer (MPW) runs,<br />
the high NRE costs of a mask set is<br />
shared among the participating<br />
customers.<br />
Fabrication of prototypes can thus<br />
be as low as 5% to 10% of the cost<br />
of a full prototyping wafer run. A<br />
limited number of tested or untested<br />
ASIC prototypes, typically<br />
10-20, are delivered to the customer<br />
for evaluation, either as<br />
naked dies or as encapsulated devices.<br />
Only prototypes from fully<br />
qualified wafers are taken to ensure<br />
that the chips delivered<br />
will function “right first<br />
time”.<br />
In order to achieve<br />
this, extensive Design<br />
Rule and Electrical<br />
Rule Checkings<br />
are performed<br />
on all designs submitted<br />
to the Service.<br />
EUROPRACTICE is<br />
organising about 130 MPW runs<br />
per year in various technologies.<br />
Multi Level Mask<br />
Single User Runs<br />
Another technique to reduce the<br />
high mask costs is called Multi<br />
Level Mask (MLM). With this<br />
technique the available mask area<br />
(20 mm x 20 mm field) is typically<br />
divided in four quadrants (4L/R :<br />
four layer per reticle) whereby<br />
each quadrant is filled with one design<br />
layer. As an example : one<br />
mask can contain four layers such<br />
as nwell, poly, ndiff and active. The<br />
total number of masks is thus reduced<br />
by a factor of four. By adapting<br />
the lithographical procedure it<br />
is possible to use one mask four<br />
times for the different layers by<br />
using the appropriate quadrants.<br />
Using this technique the mask<br />
costs can be reduced by about<br />
60%.<br />
The advantages of using MLM single<br />
user runs are : (i) lower mask<br />
costs, (ii) can be started any date<br />
and not restricted to scheduled<br />
MPW runs, (iii) single user and<br />
(iv) customer receives minimal a<br />
few wafers, so a few hundreds of<br />
prototypes.<br />
This technique is preferred over<br />
MPW runs when the chip area becomes<br />
large and when the customer<br />
wants to get a higher number<br />
of prototypes or preserie.<br />
When the prototypes are successful,<br />
this mask set can be used