Semiconductor Manufacturing Technology at Nano-C

Semiconductor Manufacturing Technology

Photoresists

Advances in semi-conductor technology are directly related to the ability of photoresist developers to create products that can be use to pattern circuits on silicon wafers with feature sizes down to 20nm and below. Photoresists are typically made of polymers but the limits of polymer based systems are being reached most notably due to the molecular weight of the polymer. The next generation of photoresists are known as molecular resists where fullerenes have significant advantages to control feature size and resolution. The advantage is both inherent due to their <1nm size and uniform nature, their ability to be chemically functionalized, chemically bond in 3-dimensions, and high etch resistance due to their high carbon content.

To enable this progression of Moore’s Law, semi-conductor fabrication technology is expected to move to Extreme Ultra-Violet (EUV) lithography. Leading chip developers, such as Intel, TSMC and Samsung, have invested several billion dollars in tool-maker ASML to accelerate the development of EUV technology. Currently, to achieve the smallest state-of-the-art features, the industry relies on multi-patterning—substantially more costly and more complex than single patterning.

Nano-C has formed an alliance with Irresistible Materials (IM) which is now working with development partners to accelerate the growth of fullerene based resists for use in EUV lithography, e-beam lithography and other applications. IM’s fullerene-based EUV resist chemistry continues to demonstrate leading edge performance for the key EUV metrics of Resolution, Sensitivity and Line Edge Roughness. IM imaging resolution capability now extends to 11 nm.

 EUV4

 

Half pitch   13nm
 LER  3.7nm
Dose to mask 110mJ/cm2
Dose to size ~48mJ/cm2 *
*Pending tool factor of the mask

Special Advantages of Fullerene Resists in Development by IM and Nano-C

  • Very small molecules (1–2 nm in diameter); theoretical resolution limit ~3 nm, an order of magnitude less than current polymers
  • Ultra-high carbon content that leads to superior etch resistance enabling sharper imaging
  • Ability to functionalize 3-dimensional molecules naturally lend themselves to single-patterning at finer resolutions, reducing or eliminating the need for multi-patterning
  • Chemistries developed with low intermolecular forces lead to the formation of smooth but mechanically and thermally stable films
  • Ultra high carbon content means very good etch resistance
  • World-class IP portfolio

Spin-on Carbon Hard Masks

Fullerene-based Spin-on-Carbon (SOC) hard-masks are frequently used to improve the photoresists’ selectivity to silicon during plasma etching.

Uses

  • Hard Mask for FinFet or Tri-gate Transistor structures
  • Gap-fill, Planarization, Underlayers
  • Hard-disk bit patterned media
  • Die attached films
  • MEMS/NEMS

Furthermore, as chip architectures become increasingly complex the use of hard-masks to improve the aspect ratio of features in silicon is critical. For many emerging multi-layer chip architectures, such as tri-layer etch-stacks, a large height to width ratio is required to maintain small lateral features (see figure below).

SoC2
SoC1
The IM/Nano-C SOC hard-mask is uniquely suited to this task due to the fullerene’s high etch durability in fluorine based ICP plasma etching. This is derived from their high carbon content. In addition, they have high temperature stability that exceeds 450 °C. With ever smaller feature sizes, current SoCs are limited due to their hydrogen content. The IM/Nano-C SoC had a much lower hydrogen content that eliminates line “wiggle” evident at these smaller features. All the properties above open the doors to novel use of the IM/Nano-C SoC in future applications like MEMS and NEMS.

Nano-C, Irresistible Materials and their development partners have demonstrated 20nm pattern transfer at aspect ratios of 10:1. Development work continues to achieve sub-20 nm patterns with aspect ratios significantly greater than 20:1. These novel SOCs will lead to reduced energy consumption in chip manufacture (replacing energy intensive CVD), but more importantly will enable high efficiency FinFET/Trigate architectures and thus low power consumption in computing while increasing speed.

The fullerene based spin-on-carbon hard-mask is now available through MicroChem, a leading distributor of electronic materials and chemicals.

Special Advantages of Fullerene Hard Masks in Development by IM and Nano-C

  • Chemistry fundamentally enabling of smaller features (<12nm) at higher aspect rations (>10:1) for continued progress in feature development
  • Eliminates of vapor-based carbon with its high capital cost and cumbersome equipment in favor of simpler SoC processes
  • Ultra-high carbon content and extremely low hydrogen content can produce films with no wiggle
  • Uniquely capable to tailor surface chemistry by application
  • World-class IP and patent portfolio

Semiconductor manufacture