IEEE Spectrum March, 2007 - 37

Manufacturing
Execution System

Engineering
Analysis Framework
VIRTUAL
FAB
PROCESS
MATCHING

RETICLE
MANAGER
MANUFACTURING
FLOWS

FAB-WIDE
SCHEDULING

FABASSEMBLY
TRACEABILITY

TRANSISTOR
PERFORMANCE
DATA
MINING

EQUIPMENT
MANAGER
EXPERIMENT
MANAGER

DISPATCHING
SERVICE

DATA
WAREHOUSE

PROCESS
ANALYSIS
YIELD
OPTIMIZATION

WORK-FLOW
AUTOMATION

a piece of software we call "the grid." It allows
all our machines and the dozens of applications
that make up the AMT suite to communicate
with each other to fully automate fab operations.
The grid is basically a giant electronic bulletin
board, where machines and wafers inside the fab
announce their respective states and locations.
The AMT programs-written in a variety
of programming languages, including C, C++,
and C#-all speak a common language: eXtensible
Markup Language, or XML. Each program posts
messages encoded in XML on the grid for other
programs to see and, if necessary, act upon. The
chip-making tools also post messages on the grid
in XML. Each tool has its own control program,
which, among other things, translates the tool's
message from machine language into XML.

TO SEE HOW THE gRId improves the manufactur-

XML messaging
"The grid" provides intelligent
routing and sequencing
of work flow

NERvE cENTER: Intel's
patent-pending grid allows all
the machines and software
modules in a fab to communicate with each other in real
time via XMl. Machines and
wafers constantly update
their status, while software
modules scan for sensor
data relating to things like
chip performance. The modules also post commands and
requests on what is essentially a fantastically complex
community bulletin board.

TOOL CONTROL

MATERIAL
DELIVERY
CONTROL

OVERHEAD
VEHICLE

STOCKERS

Material Handling and
Tool Control
42 IEEE Spectrum | March 2007 | NA

TOOL FAULT
DETECTION
MANAGER

ADVANCED
PROCESS
CONTROL

RECIPE
MANAGER

STATISTICAL
PROCESS
CONTROL

ADAPTIVE
DEFECT
METROLOGY

IN-LINE
YIELD
MANAGER

Process Control
Automation Framework

ing flow and the R&D process, let's look at a 25-piece
lot of experimental wafers-call it Lot X500. The
wafers, coated with resist, are about to go into the
stepper, where the mask patterns will be repeatedly
projected onto them. There are dozens of steppers in
each of our fabs. We'll call this one Stepper No. 8.
First, the Manufacturing Execution System
(MES) choreographs all the steps necessary to get
Lot X500 through the next manufacturing step
before anything is physically moved. The MES
knows everything about the tens of thousands of
wafers in the fab and all the machines that process
them-how many steps each wafer has gone through
and its location in the fab, for instance, or the health
of each machine and whether or not it is busy.
The MES knows, for example, that Lot X500 has
already passed through several process steps and is
sitting in a front-opening unified pod, which is basically a kind of storage and transport container for
batches of wafers. This pod is in a larger storage rack
that contains thousands of such pods all arranged
on floor-to-ceiling shelves, each identified by row
and column location. The MES maps out where
Lot X500 is and where it needs to go next-the stepper station. The MES then announces Lot X500's
virtual location on the software grid.
The Fab-Wide Scheduling module, which is
constantly scanning the grid for updates on the
thousands of pods being processed all over the
fab, sees that Lot X500 is ready for photolithography and needs to be assigned to one of the many
steppers on the manufacturing floor. The scheduler also recognizes that Lot X500 is destined to
become Core 2 Quad microprocessors-Intel's
four-core microprocessors, which will be fabricated at 45 nm-and determines which stepper is
available and qualified to do the job.
Just as the scheduling system is constantly
scanning the grid to determine tool availability and wafer locations, the tools themselves
are perpetually posting information about their
readiness to the software grid. In this case,
Stepper No. 8 signals its tool controller that it is
idle and therefore ready to accept a new lot of

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Table of Contents for the Digital Edition of IEEE Spectrum March, 2007