Multibeam (United States)

Developers of e-beam lithography systems are pursuing diverse strategies to bolster throughput. To achieve parallelism, some e-beam efforts focus on building multiple-columns, and others focus on developing columns with multiple beamlets. In this paper, we discuss the benefits and throughput of a multiple column approach for a particular application: Complementary E-Beam Lithography (CEBL). CEBL is a novel approach where the e-beam lithography system is used only to pattern the smallest features. Everything else is patterned with existing optical lithography equipment. By working hand-in-hand with optical lithography, CEBL provides an urgently needed solution to create next-generation microchips. Moreover, CEBL is extendable for multiple technology generations. We show how a multiple column approach is the best way to meet the requirements for CEBL, including high throughput, high resolution and overlay accuracy, without excess complexity or cost.

The semiconductor industry is moving to highly regular designs, or 1D gridded layouts, to enable scaling to advanced nodes, as well as improve process latitude, chip size and chip energy consumption. The fabrication of highly regular ICs is straightforward. Poly and metal layers are arranged into 1D layouts. These 1D layouts facilitate a two-step patterning approach: a line-creation step, followed by a line-cutting step, to form the desired IC pattern (See Figure 1). The first step, line creation, can be accomplished with a variety of lithography techniques including 193nm immersion (193i) and Self-Aligned Double Patterning (SADP). It appears feasible to create unidirectional parallel lines to at least 11 nm half-pitch, with two applications of SADP for pitch division by four. Potentially, this step can also be accomplished with interference lithography or directed self assembly in the future. The second step, line cutting, requires an extremely high-resolution lithography technique. At advanced nodes, the only options appear to be the costly quadruple patterning with 193i, or EUV or E-Beam Lithography (EBL). This paper focuses on the requirements for a lithography system for "line cutting", using EBL to complement Optical. EBL is the most cost-effective option for line cutting at advanced nodes for HVM.