1993_Motorola_Linear_Interface_ICs_Vol_2.pdf
1993_Motorola_Linear_Interface_ICs_Vol_2.pdf
1993_Motorola_Linear_Interface_ICs_Vol_2.pdf
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Quality improvement for a task or a process can be quickly<br />
described in terms of the target, current status with respect to<br />
target (variability), reduction of variability (commitment to<br />
never ending improvement), customer requirements (who<br />
receives output, what are a person's requirements/<br />
expectations) and economics (cost of nonconformance, loss<br />
function, etc.).<br />
Application of quality to the whole company has come to be<br />
known by such names as "Total Quality Control" (TQC);<br />
"Company Wide Quality Control" (CWQC); "Total Quality<br />
Excellence" or "Total Quality Engineering" (TQE); "Total<br />
Quality Involvement" (TQI). These names attempt to convey<br />
the idea that quality is a process (a way of acting continuously)<br />
rather than a program (implying a beginning and an end).<br />
Nevertheless for this process to be successful it must be able<br />
to show measurable results.<br />
"Six Sigma is the required capability level to approach the<br />
standard. The standard is zero defects. Our goal is to be<br />
Best-in-Class in product, sales and service." (For a more<br />
detailed explanation, contact your <strong>Motorola</strong> Representative<br />
for a pamphlet of the Six Sigma Challenge.)<br />
Quick insight into six sigma is obtained if we realize that a<br />
six sigma process has variability which is one half of the<br />
variation allowed (tolerance, spread) by the customer<br />
requirements (i.e. natural variation is one half of the customer<br />
specification range for a given characteristic). When six sigma<br />
is achieved, virtually zero defects are observed in the output<br />
of a process/product even allowing for potential process shifts<br />
(Figure 1).<br />
Policies, objectives and five year plans are the mechanisms<br />
for communicating the key beliefs and measurable goals to all<br />
personnel and continuously keeping them in focus. This is<br />
done at the corporate, sector, group, division, and department<br />
levels.<br />
Virtually<br />
Zero Defects<br />
(3.4 ppm)<br />
I<br />
Cp = 2<br />
Cpk=I.5<br />
Quality Concepts<br />
Figure 1. A Six Sigma Process Has Virtually Zero<br />
Defects Allowing for 1.50" Shift<br />
The Analog Division, for example, evaluates performance<br />
to the corporate goals of 10 fold improvement by 1989; 100<br />
fold improvement by 1991 and achievement of six sigma<br />
capability by 1992 by utilizing indices such as Outgoing<br />
Electrical and Visual Mechanical Quality (AOQ) in terms of<br />
PPM (parts per million or sometimes given in parts per billion);<br />
% of devices with zero PPM ; product quality returns<br />
(RMR); number of processes/products with specified capability<br />
indices (cp, cpk); six sigma capability roadmaps;<br />
failure rates for various reliability tests (operating life,<br />
temperature humidity bias, hast, temperature cycling, etc.);<br />
on-time delivery; customer product evaluation and failure<br />
analysis turnaround; cost of nonconformance; productivity<br />
improvement and personnel development.<br />
Figure 2 shows the improvement in electrical outgoing<br />
quality for analog products over recent years in a normalized<br />
form. Figure 3 shows the number of parts with zero PPM over<br />
a period of time.<br />
Documentation control is an important part of statistical<br />
process control. Process mapping (flow charting etc. ) with<br />
documentation identified allows visualization and therefore<br />
optimization of the process. Figure 4 shows a portion of a flow<br />
chartforwaferfabrication. Control plans are an important part<br />
of Statistical Process Control, these plans identify in detail<br />
critical points where data for process control is taken,<br />
parameters measured, frequency of measurements, type of<br />
control device used, measuring equipment, responsibilities<br />
and reaction plans. Figure 5 shows a portion of a control plan<br />
for wafer fabrication. Six sigma progress is tracked by<br />
roadmaps based on the six sigma process, a portion of which<br />
is shown on Figure 6.<br />
On-time delivery is of great importance, with the current<br />
emphasis on just-in-time systems. Tracking is done on an<br />
overall basis, and at the device levels.<br />
Six Sigma Capability<br />
Cp = 2<br />
Cpk = 1.5<br />
-60" -50" -40" -30" -20" -10 0" 10" 20 30" 40"<br />
± Six Sigma Design Specification Width<br />
MOTOROLA LINEAR/INTERFACE <strong>ICs</strong> DEVICE DATA<br />
14-2<br />
50" 60"