YIELDMANAGEMENT
There are several primary differences between the
semiconductor and the PV industry; incoming
material, volume of wafers, and data variability.
Incoming material (wafers) are a significant source
of efficiency loss however the industry has
problems identifying and tracking these issues,
wafer dimensions and weight are monitored
however the material properties are not measured
and left an unknown. Incoming batch sizes are not
Issue I 2009
fixed and can reach sizes of 5000 plus wafers.
Starts per day are easily an order of magnitude
higher than the semiconductor industry. As
factories continue to scale there will be a
tremendous volume of data to organize and
analyse to produce useful information.
-pv-management.com were likely to blame fab set up and putting the A third issue is the data variability and the need for
onus on the manufacturers. Yield management clarification of the standards. The lack of metrology
.solar
tools not only helped identify problems but also within the process leaves more reliance on final
www
changed the balance of power between test to uncover issues and pinpoint root cause.
manufacturers and tool and material providers. Wafer ID, batch, equipment tracking, and inline
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metrology can vary between factories. In many
In view of the above issues and following on from cases this information is tracked manually using
the company release of the new product a number log sheets then entered into spreadsheets
of questions were put to Rudolph Technologies to
elaborate on the new PV manufacturing analysis To meet these needs Discover’s database was
tool and what the impact such a tool could have changed to handle large volumes of wafer data
on the PV industry. and still allow very fast and efficient queries and
analysis of hundred’s of thousands of records.
The analysis then had to be modified for the
realities of the type of metrology and equipment
Fab management software has become an tracking data made available.
important part of semiconductor and related
manufacturing. This is the traditional area where One function we had is the capability to aid the
Rudolph Technologies has developed expertise. engineering group separate process problems
The company’s initial attempts focused on versus incoming material issues. This analysis links
transferring IC experience to PV. Can you please the performance data with inline metrology and
elaborate on the different needs of PV you equipment tracking data to indentify the source.
discovered and what software changes were For factories that collect this information using log
required to meet these needs? sheets we have a method to manually enter this
information into Discover Solar. While the detail
may be more coarse than a more automated
tracking system there is enough information to aid
the engineer in the analysis and experimentation.
Fab Management software is now essential in the
semiconductor world but this was not always the
case. Initially it was not automatically linked to tool
and process control until manufacturers began to
seek more data regarding the tools and processes
they were purchasing.
Are you finding the same in the PV world? Who is
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