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Magnetic recording areal densities using magnetoresistive (MR) head technology are increasing at annual rates in excess of 60% per year and in some applications as great as 100% per year. Today, the critical features of the thin-film head can be patterned with the same optical lithography techniques used by the semiconductor industry. However, with the assumption that areal density increases in magnetic recording are maintained, within the next rive years, thin-film head lithography requirements will exceed semiconductor roadmap projections. This paper describes the use of e-beam lithography as an alternative to optical lithography for the fabrication of critical features in the thin-film head. In particular, the unique geometry of the head structure, the low density of critical head features on the wafer, and the relatively low wafer volume requirements for thin-film heads allow e-beam lithography to become a viable manufacturing alternative for thin-film head fabrication. More important, e-beam lithography is ideally suited for producing thin-film head structures at a development level prior to the optimization of manufacturable optical processing.

We report sub-20 nm sacrificial nanochannels that enable stretching and translocating single DNA molecules. Sacrificial silicon nano-structures were etched with XeF2 to form nanochannels. Translocations of linearized DNA single molecules were imaged by fluorescence microscopy. Our method offers a manufacturable wafer-scale approach for CMOS-compatible bio-chip platform.

Highly scaled FinFET SRAM cells, of area down to 0.128 m2, were fabricated using high-kappa dielectric and a single metal gate to demonstrate cell size scalability and to investigate Vt variability for the 32 nm node and beyond. A single-sided ion implantation (I/I) scheme was proposed to reduce Vt variation of Fin-FETs in a SRAM cell, where resist shadowing is a great issue. In the 0.187 m2 cell, at Vd = 0.6 V, a static noise margin (SNM) of 95 mV was obtained and stable read/write operations were verified from N-curve measurements. sigmaVt of transistors in 0.187 m2 cells was measured with and without channel doping and the result was summarized in the Pelgrom plot. With the 22 nm node design rule, FinFET SRAM cell layouts were compared against planar-FET SRAM cell layouts. An un-doped FinFET SRAM cell was simulated to have significant advantage in read/write margin over a planar-FET SRAM cell, which would have higher sigmaVt mainly caused by heavy doping into the channel region.

A fully functional electron beam microcolumn, 3.5 mm in length, demonstrating a probe size of 10 nm and beam current >= 1 nA at 1 keV has been successfully developed. This paper presents its current status and future directions. Potential applications ranging from low cost scanning electron microscopy to arrays of such microcolumns for lithography, metrology, testing etc. will be discussed.

The authors report on a hybrid lithography process that integrates electron beam lithography (EBL) and optical photolithography. To maximize resolution and density, the EBL exposure is performed using a hydrogen silsesquioxane-based resist, while the photolithographic exposure is performed using standard positive or negative tone 248nm photoresists. Both exposures take place on a common underlayer consisting of an antireflective coating (ARC). During pattern transfer into the ARC layer, a composite image of the two lithographic exposures is formed creating a robust and versatile etch mask for further pattern transfer into the substrate. They demonstrate the utility of this technique by using it to pattern the active, gate, and wiring levels of complementary metal oxide semiconductor devices and circuits consisting of trigated Fin-based field effect transistors. These devices have a minimum active area pitch of 50nm, minimum gate pitch of 90nm, and achieve densities suitable for 15nm node static random acc...

A miniature Schottky electron source has been developed and evaluated for applications in a new generation of scanning tunneling microscope aligned field emission microcolumns. Both the physical dimensions and the heating power of this source have been significantly reduced from a conventional source of the same kind. Operating parameters for such a source in a microcolumn environment in terms of emission characteristics, suppressor operating range, etc., have been evaluated. Test results show that very good emission stability at ≥100 μA emission current over several hours, and axial angular current densities in excess of 100 μA/sr can be obtained. Energy distributions have been measured using a carefully calibrated analyzer, and the results show a full width at half‐maximum of 0.4 to 0.76 eV for a 0.3 μm radius Schottky source operating over an angular current density range of 1 to over 100 μA/sr. A significant change in the shape of the energy distribution was observed over this range of operation, indi...

We have built and tested a 1 keV electron‐beam microcolumn that focuses 1 nA of beam current into a 10 nm full width half‐maximum beam diameter at a working distance of 1 mm. The electron source is a miniaturized Zr/O/W Schottky field emitter with 150 μA/sr angular emission current density operating at about 1800 K at a distance of only 100 μm from a silicon membrane extractor electrode. The actual microcolumn is 3.5 mm long assembled mainly from silicon membrane electrodes. Improved einzel lens design and fabrication allowed the operation of this beam focusing element in the accelerating mode. Spherical and chromatic aberrations were reduced by factors of about 2–3, respectively, as compared to the retarding lens mode. Excellent beam current stability with less than 1% variation over several hours has been observed.

A small, 2×2×1.1 cm (height), three‐axis micropositioner has been developed. It combines sub‐nm positioning capability with a large range of travel of more than 1 mm in each direction. Its applications range from scanning proximal probe instruments to sample stages for electron or light microscopes. Two shear piezos are provided in each direction to facilitate motion. They are located at opposite sides of a moving frame which is guided by V grooves on sapphire balls (or rods). A critical point in designing this kind of positioners is how to generate the ‘‘attachment’’ force that holds the parts of the positioner together. Gravity cannot be used as the stage needs to work in all orientations. Springs, connecting the two parts moving relative to each other, generate a force in the direction of the desired motion that is changing with position, making the stage motion nonlinear. Magnets are not appropriate when low‐energy electrons are involved in the vicinity. This problem is solved by especially designed leaf springs coupled to V grooves and balls (or rods). This design allows the attachment force to remain constant and orthogonal to the direction of motion when the stage moves, thus making the motion very linear and independent of the orientation of the positioner. The positioner is exceptionally compact and can be operated in ultrahigh vacuum. These properties make the positioner attractive for atomic scale resolution scanning proximal probe microscopes and a wide range of other applications.

Schottky emission tips have been evaluated with microlenses for applications in scanning tunneling microscope aligned field emission microcolumns. Operation of Zr/O/W 〈100〉 Schottky emission tips at 1800 K with an axial separation of 50–100 μm between the tip and a microlens has been successfully tested. The microlens consists of an extraction electrode with a 5‐μm‐diam hole in a 1‐μm‐thick silicon membrane. The preliminary results of this study show that thermal field emission tips can be operated continuously in close proximity to a microlens over a long period of time, and that good emission stability of less than 1% noise fluctuation over 10 h is achieved with emission currents up to at least 100 μA.

A new method for high-resolution imaging, near-field scanning optical microscopy (NSOM), has been developed. The concepts governing this method are discussed, and the technical challenges encountered in constructing a working NSOM instrument are described. Two distinct methods are presented for the fabrication of well-characterized, highly reproducible, subwavelength apertures. A sample one-dimensional scan is provided and compared to the scanning electron micrograph of a test pattern. From this comparison, a resolution of > 1,500 A (i.e., approximately lambda/3.6) is determined, which represents a significant step towards our eventual goal of 500 A resolution. Fluorescence has been observed through apertures smaller than 600 A and signal-to-noise calculations show that fluorescent imaging should be feasible. The application of such imaging is then discussed in reference to specific biological problems. The NSOM method employs nonionizing visible radiation and can be used in air or aqueous environments for nondestructive visualization of functioning biological systems with a resolution comparable to that of scanning electron microscopy.

A piezo‐actuated locking stage is described, which minimizes stage mechanical vibrations relative to the column in a nanometer electron beam lithography system capable of using large 5‐in. diameter substrates. The performance of the piezo locking stage is compared to the performance of a laser position servo system with a resolution of about 5 nm. The measurements show that mechanically locking the stage with respect to the objective lens is far more effective than the servo loop in suppressing mechanical vibrations. With the stage locked, total beam position noise with respect to the substrate has been measured as 2.5‐nm peak‐to‐peak compared to 10‐nm peak‐to‐peak total noise for the servo loop within a bandwidth of 0.25 to 200 Hz. A more detailed analysis of the beam position noise shows that the piezo locking stage reduces the noise component which is caused by mechanical vibrations to 0.4‐nm rms.

Field emitters offer a particularly high potential in e‐beam lithography when writing in the nanometer range. Using a modified VG Microscopes Ltd., model HB 501 STEM, a current of 0.1 nA can be focused into a diameter of 2.5 nm at 100 kV with a final beam aperture of 1.6 mrad. In order to fulfill the demands of microlithography, an objective lens of 15 mm nominal focal length is used. Stage travel in the system is 5 mm in the X and Y directions and the maximum scan field is 250×250 μm2. The beam is deflected electromagnetically under computer control and vector scanning is used during lithography. The 14 bit digital pattern generator has been electrically isolated by optocouplers from the host computer and is connected via analog differential buffers to the deflection amplifiers. The cold tungsten field emitter exhibits a linear decrease in current of about 20% within 20 min of continuous writing. The decrease in current is corrected during lithography by a feedback to the clock frequency of the digital p...