This paper was written while employed at IBM where I was a part of an SPC implementation team tasked with rolling out a new in house created SPC system called ETSS (Enhanced Tool Support System). It shows the basic methods, workflow and results of one of 4 projects I led during the implementation. This paper was presented at several internal conferences and at an ASMC conference in Cambridge, MA

1. --.."--:--..-
A LARGE-SCALE SPC IMPLEMENTATION USING TIlE IBM MULTIMEDIA SPC PROGRAM
Mark Harrison and Russ Shapiro
10M Technology ProductA
Essex Junction, Vermont 05452
Abstract
This paper describes the implementation of statistical
process control (SPC) in the chemical vapor deposition
(CVD) process area of IBM's semiconductor wafer
fabricator in Essex Junction, Vermont (near
Burlington), using advanced self-study interactive
video/computer training and a series of cross-
funetional meetings for problem solving. The training
production employees received enabled them to enhance
their basic statistieal knowledge and skills while
cross-functional group meetings served as the vehicle
for bdng!ng thnt knowlndge And experf.ence together in
the manufacturing environment to establish SPC online
controls.
Introduction
IBH's corporate education group introdueed it's SPC
Implementation Program to the manufaeturing environ-
ment in February, 1990. This program uses interactive
videodiscs, computer software, workbooks and other ma-
terials to help production employees implement SPG at
the workstation level. A series of cross-funetional
meetings was· used with the video course to form imple-
mentation teams consisting of manufacturing operators,
en~ineers, maintenance personnel, statistical support
people and, in some cases, vendor personnel (Figure
1). These meGtings are where the individual's manu-
facturing Area experience.ond new SPC knowledge are
applied to specific problem solving. This paper de-
scribes how the interactive videodisc (IVD) course-and
meetings enabled IBM to introduce SPC in a tungsten
CVD process area.
Figure 1. Statisticalprocess controlInteractivevideo
disc Implementation concept.
. The 3rt; IVD Course
The SPG IVD course consists of three separate modules
designed to be used in sequence, with the succeeding
module built on the concepts of the previous one.
Training aids include 8 personal comput9r connGcted to
a laser disc player that contains video and computer
graphics images. Students interact through either a
touch-screen monitor or mouse. The monitor is capable
of displaying video, computer graphics or a combina·
tion of both simultaneously. During the course stu-
dents use the touch-screen or mouse to make topic
selection ••, s"l"ct exampl"", tnke unit or modlll<!
tests, and control how they sequence through the cur-
riculum.
Operators benefit from the IVD approach to SPG train-
ing because they can take it at their convenience and
in a uniform fashion. In addition, the training is
cost effective.
Module 1 - Starter Kit: This module contains four
units: Unit A - What is SPC7, Unit Z - Data and Vari-
ation, Unit C - Pictures of Numbers and Unit D - In-
troduction to Control Charts.
Unit A describes SPC and how it differs from other
methods of quality control. Examples of spe's benefit
to IBM and the individUAl are provided.
Unit B demonstrates the·underlying principles of SPC
using a marbl~-and-funnel experiment. Special and
common-cause variation are defined, with examples of
how SPG can help to discover them.
Unit C introduces students to the histogram, an ana-
lytical tool for visualizing variation patterns. In
this unit they learn a~out histograms and how to use
them to interpret various aspects of process behavior.
Unit D deals with control charts and how they are used
to detect variations in a process. Students also
learn how to prepare control charts. the funct Ion of
each section and some basic rules for interpreting
them.
Module 2 - A New T,ook at the Process: This module
contains one unit: Unit A - Selecting Parameters.
It teaches students how to use process block diagrams,
Pareto charts and fishbone diagrams to make decisions
about those process parameters that must be controlled
in their area. They alRo learn how to use the parame-
ter test checklists for selecting critical parameters.
Module 3 - Using SPG: This module contains throe
units: Unit A - Types of Charts, Unit B - Setting Up
end Using a Control Chart, Bnd Unit C - Interpretation
and Action.
Unit A describes different control charts and how they
are used.
Unit B enablos students to m~e sample data to calcu-
late control limits for two different types of SPC
charts following step-by-step instructions on the
videodisc and in the student Bulde.
r---~a
~--'*'-

2. Unit G teaches students how to interpret SPC charts
based on observed patterns to determine if adjustment
is needed. The students. also learn how variability·
can be reduced in the manufacturing process by using
data from control charts.
Implementation Meetings
Implementation meetings (I-meetings) are held after
students complete each course module (Figure 2).
There are three types of I meetings: I-I, 1-2 and 1-3.
The I-I meeting introduces participants to each.other,
describes what each person's role is during the imple-
mentation of SPG and answers any questions people may
have. The 1-2 meeting focuses on applying SPG to the.
semiconductor product process. Usually, more than one
session is required for this part of the implementa-
tion, with six to eight most likely necessary. These
meetings-cover a process overview, creation of process
bloek ''·diagrams,:measurement tool studies, B·· review 'of
the measurement / sampling plan, SPG system training,
fishbone diagraMS / corrective actions, SPC· chart
building and initial data colleetion / limit calcu-
lation. A third type of implementation meeting (1-3)
is held once SPC charts are in place and SPC· limits
have been calculated.
Qrganization
A formal team with cle.arly delineated responsibilities
and a specific chain of command must be established to
successfully implement SPC in a large organiT-ation.
The following job assIgnments are necessary:
Program Manager: Has overall responsibility for' cre-
ating and monitoring schedules, overseeing.training,
and reporting results. This individual should be fa-
miliar with the manufacturing environment and have
previous management experience. With all team members
reporting SPG activities to the program manager, B
clear chain of command is established.
Statistical Consultants: Teach SPC theory to those
people who have been designated SPC experts, run pilot
programs as practical on-the-job training and answer
the more difficult statistical questions.
SPC Experts: Must have the technical background to un-
derstand the statistical training they will receive.
The SPC experts who participated in the IBM Burlington
program received 100 hours of formal classroom train-
ing in statistics, which included basic, intermediate,
and advanced SPC taught on site by company statisti-
cians. In addition, these experts must understand
gro~p dy~amics to effectively lead their teams during
the implementation process. They are given this know-
ledge in group problem solving sessions that deal with
nominal group techniques, fishbone diagrams and meth-
ods for facilitating effective meetings. Another im-
portant criteria is knowledge of the area in which SPC
will be implemented.
5PC Drivers: These manufacturing operators act a~ the
SPC focal point for a partieular manufacturing depart-
ment. They assist the SPC expert in coordinating dif-
ferent training activities and performing routine
maIntenance on the area's SPC charts. In IBM
Burlington's CVD project, SPC drivers were active in
almost all technical aspects of the project.
~D.J.mQ..l~!lt~ntation
The CVD Process: The eVD process (in which SPC was
implemented) deals with the deposition of tungsten
onto the surface of a semiconductor wafer that is
later processed to create electrical interconnections
FIgure2. Tralnlngflmplementatlon flow chart.
between semIconductor devices on the integrated cir-
cuit chips that comprise that wafer. The process uses
low pressure, high temperatures and a combination of
process gases to apply a uniform film·.
Tungsten GVD Toolset: The tools used to perform this
'process consist of a large process chamber with sjx
'wafer chucks mounted in a circular arrangement on a
rotating spindle (Figure 3). Silicon wafers are
loaded or unloaded from either the lAft or right side
of the tool to allow for continuous processing. While
each wafer chuck's temperature is controlled independ-
ently, changes in deposit time affect all chucks (en-
tire process chamber). Process gases are dispensed to
the chucks through a single manifold where flow rates
cannot be individually controlled.
.Manufacturing Work Schedule: Manufacturing personnel
in this fabricator are assigned to four teams, and
work an alternate work schedule (AWS) consisting of 12
hour shifts. TWo teams work daylight hours while an-
other two work at night. To maintain B consistency
between the teams, SPC experts met with each once'a
week (four meetings/week) to collect information, re-
view results from the previous week's Work and address
new issues. The following is a chronology of events
that occurred during the.implementation meetings:
I-I Meeting (Introductory Meeting)-: The 1-1 meeting
serves as.a kick-off for the project. Manufacturing
personnel, ~ngineers, maintenance support personnel as
well as the SPG expert and the SPC program manager are
brought together and introduced to each other. Then
the SPC Implementation' Program, along with each
group's role in it is explained. The group is given a
program schedule and then reviews all phases of train-
ing required for completion.
Process
Gases
FIgure3. Tungsten CVD processchamber.

3. ,Proee!!!! Overvinw, MBnllfllcturing engineering provides
an operational overview of each toolset in the CVD
process area at this meeting, noting which parameters
affect the operation or the quality of the tool's out-
put. Pre-and-post processing operations are also re-
viewed.
Identified Processes and Parameters; A list of proc-
esses run on the tungsten CVD toolset is prepared,
with each detailed on a process bloek diagram. Brain
storming was used during the initial phases of imple-
mentation and revealed many issues about the processes
that could be addressed later. Block diagrams for
each CVD process helped participants identify prior
process effects, controllable factors (parameters),
uncontrollable factors,. measurement I inspection pa-
rameters and end-of-line electrical parameters (Figure
4).
Pnr(!to IInltlyRia Bnd nRhbone diagramll were u!led 1:0
identify those factors that caused tool I process
.downtime and the parameters most important for process
Controllable
Factors
control (Figure 5). ·Parameters such as foreign mate-
rial (FM), wafer sheet resistance (Rs), process tem-
perature and deposit time were selected for
controlling the CVD process and for determining which
ones would provide the best overall control.
Measurement I Sampling Plan Review: The measurement
sampling plan for each process tool tM.S checked for
statistical validity. with changes recommended by the
SPC expert and statistical consultant.
The sampling plan for FH required that monitor wafers
be run and read every eight hours. However, this was
changed by the group to coincide with their twelve-
hour schedule. This new sampling plan saved one moni-
tor wafer per tool (per day) with minimal additional
risk.
IBM Burlington's sample plan for tbe tungsten deposi-
tion process prior to the Impinmentation cBlls for
measuring one wafer from each product lot processed.
Measurements start with the first wafer chuck Rnd then
·nme/Temp
-Gee Row
-PreS8U1e
Previous Process
~
MeasurementJInspectlon End-of-Une Electrical
Problems Parameters Charac:terisUca
• Residual Slurry -Speed
- Realdual Resist -FM - electrical Shorts
Tungalen -R. Mean • Open.-Mushrooms
- CVD
~ ~• Chipped Walers - Ra Std. Ow•. '·Rellabillty
- Missing AnnealS
Proceas • FilmSlretta • Process Yield
• Sir ••••• Cracks • Teat Yield
t
• Warer Handling
Problems
·F.cllllles
Uncontrollable
Factors
FIgure 4. Tungsten deposlUon block diagram.
Dragglng/Sc:rapes
Travel Speed
Misalignments
End Effector
Speed
Chuck PIns
Fork Speed
Foreign
Material
FIgure s.. F1shbonediagram of tungston CVD forelg" material.

4. ·' _proceed from chuck to chuck in a circuiar pattern.
'This enables both individual chucks and the overall
.tool to be·monitored.
Process sheet resistance (Rs) measurements take the
form of a mean and % standard deviation using 13 meas-
urement sites in an X-V pattern. During the I
meetings, the SPC expert explained that using % stand-
ard deviation confounded the true variation contained
in the measurement by associating. the variability with
the mean value. The group agreed to change their
measurements from t standard deviation to standard de-
viation.
The sample pattern was also changed from a l3-site X-V
pattern to. a 19-site geometric pattern (Figure 6).
The 13-site X-V pattern biased the wafer average to-
ward center measurements where swings in edge measure-
ments minimally affected the average. The 19-site
geometric pattern distributes the points so that each
now represents an equal amount of the wafer surface
area, thereby resolving the sensitivity problem at the
edge of the wafer and providing more accurate process
information.
Measurement Tool 5tudies: A gauge capability study
was performed for the Rs measurement tool, using a
standard wafer (usually a process monitor) for cali-
bration checking and daily data collection. This cal-
ibration check wafer would be used for data
collection. A program was then wrItten for the Rs
tool to measure one site five times without moving the
check wafer. This measurement was taKen once on each
shift for three weeks and recorded in a log book.
The results were analyzed by the SPC expert to deter-
mine the overall capability of the measurement tool
and break down the total variability into short-term
and long-term components. The result of this capabil-
ity study on the measurement tool revealed a
process/tolerance (P/T) ratio of less than .1 (.07 and
.022) for the two different tungsten deposition proc-
esses in the area. Short-term repeatability was found
to be 35 % of total variability, while long-term vari-
ability made up 65 %. This study revealed that the Rs
measurement tool was more than capable of satisfying
process area requirements and that no action was nec-
essary to improve its performance.
SPC Control I Report~g System: Before 5PG was imple-
mented, engineering provided manufacturing with a per-
sonal computer-based data collection/process control
system that consisted of three computers, one located
by each .group of process tools. These computers could
neither communicate with each other nor transmit data
to remotl! !;ystems. lIowever, they did help to center
wafer chuck temperatures and· tungsten deposit time af-
ter tool maintenance had occurred by flagging process
data that exceeded SPecification limits (although
these limits were not statistically derived).
13 Slt.s
Method
19 Sites
Method
Figure6. Tungsten depositionwafer sample plans.
Various SPC control/reporting systems were reviewed
during the 1-2 meetings. A new system being installed
in the· manufacturing area, called enhanced tool sup-
port system (ETSS), was selected.
ET55 Features: A local area nl!twork (LAN) based sys-
tem, ETSS allows data to be accessed and entered any-
where a terminal is located •. This enables engineers
to .view real-time process data in their offices while
operators on the manufacturing floor can check 5PC
control charts for a particular tool without having to
physically be at the tool (Figure 7).. The terminals.
are PS/2 Hodel 80s while the sy.stem:-servers (primary
and backup) are PS/2 Hod.el 9Ss. IBM Burlington's in-
formation systems (l/S) organization is currently con-
structing a prototype of a fast~r vl!rsion of ETSS
using a RISe 6000 system as the network server.
The statistical functions of ETSS. were developed by
site statisticians working with l/S., With the follow-
ing functions, ETSS allows timely and accurate control
of processes on the manufacturing floor:
Each SPC chart can store up to 250 data points with
user entered comm.ents for each one. This allows a
root cause analysis (RCA) to be conducted, with chart
comments used as a data base. Data can be transmitted
to a remote data base for long term storage.
SPG charts have six separate control limits that can
be individually programmed to flag based on user de-
fined conditions (i.e., seven points in a row above
the target). Flags can be programmed to automatically
access the SPC chart, re-calculate a process setting
based on a corrective action algorithm, inhibit the
tOol from processing any additional product via the
manufacturing floor control system until the situation
has been corrected, or 'a combination of the above
(Figure 8). In the CVD area, all features are used
except the tool inhibit, which is planned to be on
line in the near future.
r
ETSS can also calculate process capabiU.ty indices
(Cp, Cpk) fo~ display on SPC charts.
Fishbone Diagrams / Corrective Action: Fishbone dia-
grams were used to brainstorm and list all of the
causes for particular out-of-control situations. This
was a complex process and, in some cases, a rib of the
fishbone had it's own fishbonel These causes were
prioritized and translated into a set of corrective
action messages, which were entered into the ETSS sys-
tem. They are now being used by operators to correct
out-of-control situations. Fishbone diagrams for FH,
Rs ml!an and Rs standard deviation were developed for
the tungsten CVD area.
Chart Building / Structure: TWo charts per tool, (one
for each load/unload chamber) are being used to track
FM.
The group, working with the statistical consultant,
devised a new sampling technique for tungsten deposi-
tion tools that measures all six wafe~ chuck faces at
once and corrects the individual wafer chuck tempor-
atures, if flagged. If the run average chart is
flagged, an algorithm centers all the wafer chuck tem-
peratures around the nominal process setting and com-
pensates by recalculating the deposit time. The
objective of this technique is to keep all six wafer
chucks operating as close to the nominal process tem-
.perature as possible so that a tungsten film of con-
sistently high quality is deposited on the wafer. The
-mean and standard deviation of each wafer chuck, the
run average, range of means of the wafer chucks, and
deposit time are being tracked for Rs. This results
in a total of 15 charts for each tool/process comhi-
nation.
, X9H
'--"-~

5. "-
)Process Data
ETSS
r....
A v
)KTOOI Control feedbaek SPC
Tool Inhibits
Computer Short-Term
v Manufacturing
" "-Terminal Data Point Comments "- Process
"-
Control System
:: Data Resolve Tool Inhibits )
Resolve Tool Inhibits ) Storage v
v
'11
C;n
III
'"'"0
•••
~
Long-Term
Process
Data Storage
Agure 7. Manufacturing systems block diagram.
1.50 r------------~
0.00
~-g
.: 1.00 1------,=-----------1
(8) ~
:g
8,0.50
III
o
•1 1#2 113 114
WalerChuck
tl5 #6
1.50.--------------,
~'t:I
10 1.00
(b) ~
1i
8,0.50
CD
o
0.00
#1 #2 #3 #4
Wafer Chuck
#5 tl6
Figure 9. Tungsten CVD process eapllbliity (a) without SPC
controls and (b) with SPC controls.
OS/2 / ETSS Training' Because ETSS ~s OS/2 based, eV-
eryona involved in the implementation had to learn two
new systems before SPG could be properly implemented.
Each team learned how to access icons, shrink and ex-
pand windows, use the mouse and access the applica-
tions available on the system, including ETSS.
ETSS training focused on data entry. ,SPC chart view-
ing, Rccessing correctlve action messages and the en-
tering of comments on a data point.
Collecting Data: Once system training was completed,
operators began entering data into ETSS. Current
process specificationR Were used to establish limits
on the initial SPC charts untH enough data was col-
lected to calculate actnal statistical control limits.
·At first, people were unsure about the adjustments re-
commended by the corrective action algorithms, which
prompted them to continue making process adjustments
without calculated guidance. After discuRsing the
problem as a group. it was decided to pilot tbe activ-
ity on one tool so that the accuracy of the new system
could be determined. The pilot tool ran well. which
raised the confidence of manufacturing operators in
the system's accuracy. The transition to using ETSS
bas now been 'made on aLl process tools .
Process Document Updating:, Both engineers and the SPC
expert rev~ew current process documentation and update
it. when needed, to reflect SPC control methods.
While process specification limits and targets remain
unchanged, both control limits and modified control
limits are defined as ETSS SPC limits.
1-3 Meeting: This meeting marks the completion of in-
itial implementation. Each team reviews SPC charts
with the new control limits. ~odi£ied Control limits
are also explained, with examples given to show how
they are used to protect specification limits.
Process Results
When our teams began operating tools with SPC, results
were almost immediate. The change in process capabil-
'ity for tungsten deposition oVer a one-month period is
shown in Figure 8. Further improvements are expected
as active tool controls continue to be applied to re-
duce process variability.
Post Implementation
SPC must be woven into the fabric of the business if a
manufacturer is to realize full benefit from it. This
means data must be entered in real-time, interpreted,
and used to make technical decisions.
This is being accomplished at IBtIBurlington with
weekly technical review meetings. These meetingR in-
clude representatives from all four manufacturing
teams, engineering, maintenance, and the SPC expert.
Although the meeting is informal, all aspects of the
area are addressed, including process, maintenance,
production, and control.
~---,
,.•--...•.~"

6. 4 -,
·Sqme of the projects currently unclnrway include the
improvement of wafer handling in -the tooI-· to-·-reduce
scrap, ft :ltudy of the differlmee§ b••tw ••••n product and
monitor m@IJSUtl!Ml!nts,and a plan for reducing FM. To
increase management awareness of its SPG activities,
the group has presented it's results as- part of the
fabricator's monthly continuous improvement (meeting)
program.
SPC IVD training has proven to be a valuable tool for
installing on line controls inth ••tungsten GVD area,
with the cross-functional team approach providing the
technical expertise required for such a complex task.
Manufacturing employees have found IVD training to be
convenient, consistent and an effective way_to acquire
the knowledge they need to implement SPG. Implementa-
tion meetings provide a logical structure for inte--
grating online experience, new ideas and statistical
knowledge into the manufacturing environment· and
achieving necessary improvements.
Results from complete process reviews, measurement
tool studies and the creation of ETSS SPC charts have
been very encouraging. On one tungsten level, the
process capability (Cp) improved from .893 to 1.278 (+
_43%) while Cpk·· (process centering) values went from
.753 to 1.215 (+ 61%).
In addition to it's technical accomplishments, the
Tungsten SPC project improved teamwork by involving
engineers, maintenance people, and manufacturing oper-
ators from all teams in implementation meetings. Man-
ufacturing operators were empowered- -because they
learned more about their processes and how they relate
to product quality. In addition, they were involved
in establishing controls and in deciding how best to
respond to out-of-control situations. Ongoing techni-
cal review meetings are used to address problems and
devise methods for ensuring ongoing process and tool
performance improvements.
Acknowledgements
The authors acknowledge Gary Snyder for his statis-
tical expertise and guidance, Jack Phillips of
tungsten CVD engineering for his technical support and
guidance, and the SPC drivers - Hark DeSimone, Kent
Irish, Keith Chapman and Hark Nielsen - for.their con-
tinuing support.
, ~9H
-.---.---"