Paper Presentation on

1. Paper Presentation on (EUVL) Presented By: Sweta Shalini Lal Krishna

2. Why EUVL? • The process used to transfer a pattern to a layer on the chip is called Lithography. Demerits: • It become more difficult to transfer accurate images onto a photo resist layer as line widths become smaller. • The vertical sidewalls are rough because metal films have relatively large grains. • There is also a need to repair defects such as clear defect and opaque defect.

3. Fabrication of Extreme Ultraviolet Lithography Fig 1. is a cross-sectional view of a mask substrate covered with an etched stop layer 12-oxide layer 14-silicon layer 16-molybdenum layer 18-second silicon layer 10-reflective substrate

4. 12- SiO2 (thickness-50A°) 20-silicon layer Fig 2. illustrates the substrate of Fig 1. after a silicon layer has been formed over the etched stop layer. 30-silicon layer 32-reflective region 34-verticle sidewalls Fig 3. illustrates the substrate of Fig 2. after the photo resist have been patterned and the Si layer has been etched .The resulting structure includes Si members and reflective region.

5. Fig 4. illustrates the substrate of Fig 3. after a layer of metal has been deposited. 40-nickle layer (approx. 600A°) 50-absorbing member Fig 5. illustrates the substrate of fig 4. after the Si members have been converted into the absorption members.

6. Advantages of using nickel: • Dimensions of silicon members (30) do not changes significantly when they are transformed into nickel silicide. • Silicide formation can be don e at low temperature. Fig 6. illustartes the substrate of the metal and the oxide (etched stop layer ) has been etched .

7. 120-etch stop layer 70-clear defect 72-opaque defect Fig 7. illustrates the substrate of fig 2. after the photo resist has been patterned and the Si layer has etched .The resulting structure includes Si members and a Si artifact that can result in an opaque defect in the reflective region. • Clear defect- It occurs when mask is inadvertently removed. • Opaque defects: It occurs when mask material or debris that act as a masking material is present .

8. Fig 8. illustrates the substrate of fig 7. after the opaque defect has been repaired in the reflective region . • 80- Gallium stain • The gallium stain is caused due to damage of each stop layer by gallium ion . Fig 9. illustrates the substrate of fig 8. after a layer of metal has been deposited.

9. Fig 10.illustrates the substrate of Fig 9.after the Si members have been converted into the absorption members Fig 11.illustrates the substrate of Fig 10. after the metal has been etched.

10. Fig 12. illustrates the substrate of fig11. after the clear defect has been repaired in the absorption member. • The patch(130) absorbs electromagnetic energy at a predetermined wavelength such as EUV. • After the excess metal is removed , the clear defect is repaired as depicted in fig 12.

11. Fig 13.illustrates the substrate of fig12. after the metal and the oxide (etched step) layer have been etched. • The novel mask fabrication process described above provides improved critical dimension control over conventional metal film mask. This result is achieved by etching a layer of silicon to form silicon members into a nickel silicide. In addition , defects in the mask are repaired , thus ensuring that an accurate image of the mask is cast onto substrate.

12. EUVL Machines • EUVL machines or systems are used for producing integrated circuits (IC) components , such as transistors formed on a substrate. • It utilizes a laser plasma point source directed via an optical arrangement onto a mask which is reflected by a multiple mirror system onto the substrate or target. • They operate in the 10-14 nm wavelength soft x-ray photons.

13. Future Prospects of EUVL • With the help of EUVL microchips 10 times faster than today’s most powerful chips and memory chips with much more capacity can be made easily. • . Current lithography technology is expected to allow manufacturers to eventually print circuits as small as 0.1 micron in width, or 1/1,000th the width of a human hair. • Processors built using EUV technology are expected to reach speeds of up to 10 gigahertz (GHz) in 2007. By comparison, the fastest Pentium 4 processor today is 1.5 GHz. • The consortium includes Berkeley Lab, Sandi-California National Laboratory, Lawrence Livermore National Laboratories, Intel, Motorola, Advanced Micro Devices, Micron Technology, Infineon Technologies and IBM.

14. The founder of Intel Gordon Moore , proposed a law well known as Moore’s Law: “The complexity for the minimum component costs has increased at rate of roughly a factor of two per year …… Certainly over short term this rate can be expected to continue , if not to increase. Over the longer terms , the rate of increase is a bit more uncertain , although there is no reason to believe it will not remain nearly constant for at least 10 years.” • Companies like AMD, IBM, and Intel will continue using silicon to build smaller and faster microprocessors for at least another ten years, but not without the help of extreme ultraviolet (EUV) lithography, a new way of printing circuit patterns onto silicon that eschews lasers and lenses in favor of xenon gas and microscopic reflectors. • Tried-and-true optical lithography techniques that print patterns with features as narrow as 65 nanometers will extend Moore's Law into 2007. Only EUV can stretch it into the next decade, shaving feature widths to 32 nanometers.

15. CONCLUSION From the previous discussions we conclude that EUVL Technology can built smaller and smaller circuits , more compact chips reducing the power consumption . The EUVL consortium, a Intel led group that includes AMD,IBM, Micron Technology and Motorola hopes to debut EUV around 2009, shrinking CPU feature widths to around 32nm. But the technology needed fine tuning . It is still not clear that this will be a cost –effective solution or not.

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