III. Writing exercises:

Exercise 1. Complete the sentences with the suggested words:

performance, everyday, top, technologies, end.

To that ________, some of the ________ minds in the industry are at work at TI ________ developing silicon process ________ that improve ________, increase battery life and reduce cost.

Exercise 2. Fill in the table with words and expressions from the text:

	parts	systems	process
Example: new deep-submicron process technologies are pushing			the physical limits of what we can do with transistors
we believe that in-house semiconductor R&D provides
we work to improve
Our own state-of-the-art fabrication plants are

Exercise 3. Compose a story on one of the topics (up to 100 words):

“Semiconductor Industry”

“Integrated Circuits Products”

“Silicon Process Technologies”

Lesson 8

Read the text: Lithography

Lithography is the gating function in the development of new CMOS manufacturing processes. While all semiconductor manufacturers are dependent on the same available lithography tools, the ways of using those tools vary depending on the expertise and requirements of the manufacturer.

At Texas Instruments, we have a long history of innovation in lithography. Our expertise allows us to develop leading-edge processes with the right balance of performance, cost and power consumption for our customers.

As the critical dimensions of transistors get smaller, it becomes increasingly difficult to focus light on the areas of the chip where the photoresist must be exposed. Today's argon-fluorine (ArFl) lithography tools, which provide light at a wavelength of 193 nm, are used to pattern critical dimensions as small as 70 nm for transistor gates in the 130-nm process. As the 90-nm process goes into production, the smallest critical dimension are dropping below 40 nm—five times smaller than the light wave that forms it.

Obviously, we have to maintain tight control of these critical dimensions so that the transistors formed are consistent in their scaling. Embedded phase shifting within the reticule enables us to focus light at sub-wavelength dimensions. Models built using our experience with the process allow us to employ optical proximity correction (OPC) to ensure that the effect of exposure is uniform across the wafer. We are also developing reticule enhancements, such as sub-resolution assist features for stricter process margins, as we enter volume production.

These types of improvements drive up the cost of making reticules. As a result, it is no longer economical to make numerous versions in developing the right set of reticules for a new product. Instead, we are learning to build the complexities required of deep-submicron lithography into the reticule from the very beginning. This process keeps time and expense to a minimum.

With an eye to the future, we anticipate the availability of the next generation of lithography tools. These tools will shrink light wavelengths to 157 nm. Extreme ultraviolet (EUV) is proposed to take us beyond that point. Electron beam projection printing is also likely to become important as the alternative technology matures. For Texas Instruments’ R&D, the key issue with these tools, as with other fundamental process developments, is how we can use them to build products with the right mix of performance, low cost and power efficiency for our customers.