I noticed that many of your reference and a lot of the methods seem to be applied to the Wafer fabrication or IC industry. Why is this?

Are the Integrated Yield Management Methods only applicable to the Wafer or IC Industries?

Wafer fabrication is a high-precision, multi-step process with the Best-In-The-Class International Fabs achieving total yields in the high 90%. This is a very significant accomplishment when you consider many of the IC processes must perform hundreds of very complicated steps with minimum to no rework capability. All of which must be performed continuously over a cycle time extending many weeks, even months. Consider the graph showing the impact of individual process or step yield on the total yield.

Consider that for a 100 step process, with a yield of 99% at each step, the total or final yield would be approximately a mere 40%. Obviously these Fabs are doing something that is worth learning.

Definitely not! Integrated Yield Management Methods is a process which is applicable to most many multi-step, complicated procedures. It has successfully applied to the, Head Disc Assembly in the disc drive industry; panels and display technologies; business processes like accounts payable; equipment manufacturing; software development; and numerous other industries. And, YSI is always looking for new applications and industries that would benefit from the Integrated Yield Management Methods.

Six-Sigma is a set of quality tools which focuses on reducing variability in a process to 3.4 defects per million or better. It originated at Motorola in the 80’s and has traveled throughout the globe, with applications in manufacturing and business process.

Lean Manufacturing is “a philosophy of production that emphasizes the minimization of the amount of all the resources (including time) used in the various activities of the enterprise. It involves identifying and eliminating non-value-adding activities in design, production, supply chain management, and dealing with the customers. Lean producers employ teams of multi-skilled workers at all levels of the organization and use highly flexible, increasingly automated machines to produce volumes of products in potentially enormous variety. It contains a set of principles and practices to reduce cost through the relentless removal of waste and through the simplification of all manufacturing and support.” (http://scrc.ncsu.edu/public/DEFINITIONS/J%20-%20L.html). Lean Manufacturing, also called Just-In-Time Production has roots with Eli Whitney and interchangeable parts, with further development by Henry Ford, and later by the Toyota Motor Company.

Integrated Yield Management Methods is a systematic methodology of improving Yield and Other Productivity metrics on complicated and highly interdependent processes. Its major focus is an examination of the entire Enterprise with respect to Pre-production, Development, Manufacturing and Customer methods and integration into a working, manageable program. Many quality programs only deal with snap-shot areas, where as IYMM attempts to deal with the whole Enterprise as a single unit for managing and maximizing current assets and intellectual property investments. Integrated Yield Management Methods (IYMM) starts with a high-level review of the process, defining and quantifying the monetary effect of yield loss and the potential monetary gain through yield improvement.

Initially, IYMM provides focus on the development and design phase of the process and product. There is no sense developing processes and automation which haven’t been optimized for manufacturing. IYMM ideally starts long before the processes goes into manufacturing. Here, IYMM emphasizes the application of Fault Avoidance and Yield Enhancing methods.

The thrust of IYMM then continues into the Pre-production and Manufacturing phases.
This step systematically quantifies the yield loss components of the process or sub-processes, called Long-Loop Quantification. After Long-Loop Quantification, the IYMM flow moves to Short Loop Controls, real time Statistical Process Control, and feed-back and feed-forward prediction and integrated data systems.

Central to the IYMM flow is the integration and manipulation of data to create information becoming paramount to the success of IYMM and the integration of numerous engineering functions into Enterprise wide operations like Cost, Marketing, Development, Sales, etc.

This is only a brief overview of a few of the tools, methods, and processes used in IYMM. There are, of course, many other methods that make IYMM so unique such as differentiation of random and systematic yields, assignment of yield ownership, and focus on common causes as opposed to special causes. The important distinction to remember is that it is a total integrated methodology affecting and achieving yield improvement and monetary gain across the entire Enterprise.