New advances with REBL for maskless high-throughput EBDW lithography

Abstract

REBL (Reflective Electron Beam Lithography) is a program for the development of a novel approach for highthroughput maskless lithography. The program at KLA-Tencor is funded under the DARPA Maskless Nanowriter Program. A DPG (digital pattern generator) chip containing over 1 million reflective pixels that can be individually turned on or off is used to project an electron beam pattern onto the wafer. The DARPA program is targeting 5 to 7 wafers per hour at the 45 nm node, and this paper will describe improvements to both increase the throughput as well as extend the system to the 2x nm node and beyond.This paper focuses on three specific areas of REBL technology. First, a new column design has been developed based on a Wien filter to separate the illumination and projection beams. The new column design is much smaller, and has better performance both in resolution and throughput than the first column which used a magnetic prism for separation. This new column design is the first step leading to a multiple column system. Second, the rotary stage latest results of a fully integrated DPG CMOS chip with lenslets will be reviewed. An array of over 1 million micro lenses which is fabricated on top of the CMOS DPG chip has been developed. The microlens array eliminates crosstalk between adjacent pixels, maximizes contrast between on and off states, and provides matching of the NA between the DPG reflector and the projection optics.

Atomic Layer Deposition of W:Al2O3 Nanocomposite Films with Tunable Resistivity

“…Thin film materials comprised of blended conducting and insulating components have been utilized in a wide variety of applications including resistive layers for electron multipliers such as microchannel plates,1–3 resistive memories,4–8 electro‐chromic devices,9–15 biomedical devices,16–18 and charge‐dissipating coatings on micro‐electromechanical systems (MEMS) devices 19–23. The physical and electrical properties of composite thin films can be tailored by adjusting the relative proportions of the constituent materials.…”

Characterization of Fogging and Develop-Loading Effects in Electron-Beam Direct-Writing Technology

“…[1][2][3][4][5] It also seems to be one of the most promising techniques for manufacturing nextgeneration LSIs by multiple EB writing. [6][7][8][9][10][11][12][13] Owing to the continuing decrease in LSI feature size, higher critical dimension (CD) accuracy is required. To improve CD uniformity, it is necessary to take into account long-range CD error factors as well as the conventional proximity effect correction [14][15][16] that occur within the micrometer range.…”

Electron caustic lithography

“…10 ECL is entirely compatible with a multiple column architecture which can, in principle, reduce the required beam current in any one column, and realise several tens of wafers per hour. 13 Further improvements are likely in throughput for reflective electron beam lithography systems and ECL will also benefit from such developments.…”

“…In REBL, the role of the mask is played by the digital pattern generator (DPG) developed by Petric et al, 12,13 which is a sophisticated array of electrostatic mirrors that create the pixels of the image projected onto the resist. As a logical extension, the flexibility of ECL could be improved by adopting a DPG with every individually controllable pixel 'on,' i.e.…”

“…2,8,9,11 In addition there has been a development of maskless approaches, including the use of multiple beams, 14,15 low energy electron microscopy, 10 and reflective electron beam lithography (REBL) wherein the electron beam is reflected by an array of electrostatic mirrors. 12,13 In this letter we describe a complementary approach to REBL and electron projection lithography which is based on the formation of intense electron caustics which can be subsequently projected onto a resist by suitable electron optics. The caustics are formed within the cathode lens of a mirror electron microscope (MEM) in which electrons turn around in the vicinity of a negatively biased specimen surface.…”