Christopher F. Bevis

Nanoclusters of MoO3−x embedded in an Al2O3 matrix engineered for customizable mesoscale resistivity and high dielectric strength

We have synthesized a material consisting of conducting metal oxide (MoO3−x) nanoclusters embedded in a high-dielectric-strength insulator (Al2O3) matrix. The resistivity of this material can be customized by varying the concentration of the MoO3−x nanoclusters. The Al2O3 protects the MoO3−x from stoichiometry change, thus conserving the number of carriers and maintaining a high dielectric strength. This composite material is grown by atomic layer deposition, a thin film deposition technique suitable for coating 3D structures. We applied these atomic layer deposition composite films to our 3D electron-optical micro electrical mechanical systems devices and greatly improved their performance.

The REBL DPG: recent innovations and remaining challenges

Reflective electron-beam lithography (REBL) employs a novel device to impress pattern information on an electron beam. This device, the digital pattern generator (DPG), is an array of small electron reflectors, in which the reflectance of each mirror is controlled by underlying CMOS circuitry. When illuminated by a beam of low-energy electrons, the DPG is effectively a programmable electron-luminous image source. By switching the mirror drive circuits appropriately, the DPG can ‘scroll’ the image of an integrated circuit pattern across its surface; and the moving electron image, suitably demagnified, can be used to expose the resist-coated surface of a wafer or mask. This concept was first realized in a device suitable for 45 nm lithography demonstrations. A next-generation device has been designed and is presently nearing completion. The new version includes several advances intended to make it more suitable for application in commercial lithography systems. We will discuss the innovations and compromises in the design of this next-generation device. For application in commercially-practical maskless lithography at upcoming device nodes, still more advances will be needed. Some of the directions in which this technology can be extended will be described.

Digital pattern generator: an electron-optical MEMS for massively parallel reflective electron beam lithography

Abstract. The digital pattern generator (DPG) is a complex electron-optical MEMS that pixelates the electron beam in the reflective electron beam lithography (REBL) e-beam column. It potentially enables massively parallel printing, which could make REBL competitive with optical lithography. The development of the REBL DPG, from the CMOS architecture, through the lenslet modeling and design, to the fabrication of the MEMS device, is described in detail. The imaging and printing results are also shown, which validate the pentode lenslet concept and the fabrication process.