Before we discuss the software that runs our R&D line and fabs, here are the basics of the chip-making process it controls.

A wafer begins its trip through the fab as a ­mirror-polished disk of 99.9999999 percent pure silicon, 300 mm in diameter and not quite a millimeter thick. The wafer then passes through the first of many patterning processes to create the chip’s astounding profusion of transistors [see “Hands Off”]. These patterning processes, known as photolithography, are the heart of chip making and they are carried out repeatedly, up to 30 to 40 times for an advanced chip like a 64-bit Itanium microprocessor.

Each time a wafer goes through one of these photolithography cycles, a liquid polymer called a photoresist is applied to it. Then it goes into a step-and-repeat projection camera, better known as a “stepper,” which exposes a pattern onto the resist-coated wafer. For each exposure, the stepper moves to a new position, each one corresponding to a single chip.

The pattern is projected onto the wafer in ultraviolet light through a photomask, a thin plate of transparent quartz covered with the pattern defined in chrome of a particular chip layer. After the wafer has been exposed, it is washed with a solvent, removing the undesired resist and leaving the image of the photo­mask on the wafer.

Each time the wafer is patterned, one of three different processes is performed. In some cases, the wafer will be etched to remove material. This can involve a liquid acid or a high-temperature plasma, both of which will eat away any surface not covered by the resist. During other steps, the wafer is put through another diffusion or deposition process that adds material to it. In this case, the resist acts as a barrier, preventing the new material from adhering to parts of the wafer.

The third process involves changing the concentration of ions in parts of the wafer to adjust the conductivity of the semi­conductor. Here the resist again acts as a barrier, preventing the ions from penetrating into the protected parts of the wafer. After the wafer has been processed, all the remaining resist is removed with a special solvent.

This process is repeated many times to create all the components of a transistor. Then, the process is repeated several more times, adding layers of metal interconnects to the components to create functional circuits. Afterward, insulating material is added to the wafer, the wafer is patterned for interconnects, metal is deposited and polished smooth, and the next layer of insulation is added.

While the basic chip-making processes have been around since the early days of semiconductor manufacturing, more than 35 years ago, several significant changes have occurred. For instance, there are a lot more photolithography cycles today to create the layers of wires needed to connect the proliferation of transistors mandated by Moore’s Law.

Also, shorter wavelengths of light are used to resolve smaller features, new materials are always being introduced, new processes such as plasma etching and silicon straining have come into vogue, and optical tricks of remarkable complexity are employed to produce features even smaller than the wavelengths that are resolving them.

And, last but not least, the whole process is now controlled by software.

The AMT suite has four major components: the Manufacturing Execution System, the Process Control Automation Framework, the Engineering Analysis Framework, and the Material Handling and Tool Control. Each is composed of several programs, and each of those programs controls a different part of the chip-making process.

One program in the Manufacturing Execution System that’s called Fab-Wide Scheduling, for example, acts like the world’s most sophisticated traffic cop: it tracks all the wafers through the fab to ensure that they pass in and out of different machines in sync with all the other wafers that are simultaneously moving from machine to machine. Another program, in the Process Control Automation Framework called Advanced Process Control, automatically detects random variations in the processing equipment—maybe a chemical vapor deposition machine has deposited too much metal to make a wire, for instance—and adjusts the recipe accordingly.

On each manufacturing line, as well as on the main technology development line where we refine recipes for new chips, the AMT system takes thousands of readings from hundreds of machines. There are defect-density and film-thickness readings from quality inspection tools, temperature and pressure readings from deposition and etch tools, and even readings of the velocity of the gas flowing to diffusion furnaces. All this information feeds into the fab’s database, which typically contains tens of trillions of bytes of data, or five to 10 times the amount of information you’d find in the entire print collection of the U.S. Library of Congress. These data are crucial to determining the merits of the different recipes our researchers experiment with while creating a new chip. Automated engineering programs, part of the Engineering Analysis Framework, evaluate transistor performance, wafer yields, and manufacturing processes related to the chip-making experiments run on the technology development line. These proprietary programs identify recipes that improve transistor performance and the yield of chips, reduce power consumption and heat dissipation, and otherwise help produce better chips faster. This automated analysis of hundreds of thousands of data points enables fast tuning of the manufacturing recipes in the fab.

How fast can these recipes be put into use? In the blink of an eye, basically. Once we determine that a new recipe works for, say, an etching bath, the system feeds it back to the chip-making tools on the technology development line and starts using it right away. So a batch of wafers that is already in the midst of photolithography can benefit immediately from these revised instructions.

For example, suppose a wafer lot has just been exposed in a stepper and is awaiting a cleansing chemical bath in an etcher. By the time it gets to that etching bath, there might be a better recipe awaiting the wafers than the one used for the batch that just exited the machine. These experiments continue until the microprocessor recipe is fine-tuned for use in all the company’s high-volume manufacturing lines.

The AMT suite of programs has improved tremendously over the last couple of decades. The most recent innovation, developed by Intel’s Logic Technology Development group, is 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.