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The discussion on reticle cost continues to raise questions by many in the semiconductor industry. The
diamond industry developed a method to judge and grade diamonds. [1, 11] The diamond-marketing tool of "The
4Cs of Diamonds" and other slogans help explain the multiple, complex variables that determine the value of a
particular stone. Understanding the critical factors of Carat, Clarity, Color, and Cut allows all customers to
choose a gem that matches their unique desires. I apply the same principles of "The 4Cs of Diamonds" to
develop an analogous method for rating and tracking reticle performance.
I introduced the first 3Cs of reticle manufacturing during my BACUS presentation panel at SPIE in February
2008. [2] To these first 3Cs (Capital, Complexity, and Content), I now add a fourth, Cycle time. I will look at
how our use of reticles changes by node and use "The 4Cs of Reticles" to develop the key performance
indicators (KPI) that will help our industry set standards for evaluating reticle technology.
Capital includes both cost and utilization. This includes tools, people, facilities, and support systems required
for building the most critical reticles. Tools have highest value in the first two years of use, and each new
technology node will likely increase the Capital cost of reticles.
New technologies, specifications, and materials drive Complexity for reticles, including smaller feature size,
increased optical proximity correction (OPC), and more levels at sub-wavelength. The large data files needed
to create finer features require the use of the newest tools for writing, inspection, and repair.
Content encompasses the customer's specifications and requirements, which the mask shop must meet. The
specifications are critical because they drive wafer yield. A clear increase of the number of masking levels has
occurred since the 90 nm node.
Cycle time starts when the design is finished and lasts until the mask house ships the reticle to the fab.
Depending on the level of Complexity, a reticle can take from as few as one, to more than forty, days to build.
By using the 4Cs, I can show how the reticle build has changed from the 90 nm technology node. I will begin
by delineating proposed KPIs for reticles.
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