Juan R. Maldonado

Bio: Juan R. Maldonado is an academic researcher from IBM. The author has contributed to research in topics: X-ray lithography & Lithography. The author has an hindex of 17, co-authored 88 publications receiving 926 citations. Previous affiliations of Juan R. Maldonado include Rutherford Appleton Laboratory & Applied Materials.

Electrostatic or vacuum pinchuck formed with microcircuit lithography

Abstract: A pinchuck is formed in accordance with this invention by using lithographic techniques to define and to etch a pattern of pins from an extremely flat etchable surface. Since the pins are formed from a surface which is already flat, it is not necessary to level or polish the pins after they are formed. Since lithographic techniques are used, the pin head dimensions, the number of pins, the arrangement of pins, and the density of pins all may be freely chosen without affecting the fabrication cost. By surrounding the region of etched pins with an unetched band, a raised peripheral ring will be formed which can act as a vacuum sealing ring when the pinchuck is used as a vacuum pinchuck. By fabricating the pins from an electrically conductive material (such as doped silicon) and then covering the pins with a dielectric film (such as silicon dioxide), the pinchuck can be used as an electrostatic pinchuck. By doing both, the same pinchuck can be used as an electrostatic pinchuck or as a vacuum pinchuck or as both simultaneously.

Generating electrons with an activated photocathode

Abstract: An electron beam apparatus comprises a beam source to generate a radiation beam that is directed onto a photocathode to generate an electron beam. The photocathode comprises an electron-emitting material composed of activated alkali halide, such as for example, cesium bromide or cesium iodide. The activated alkali halide has a lower minimum electron emission energy level than the same material in the un-activated state, and provides efficient photoyields when exposed to radiation having an energy level that is higher than the minimum electron emission energy level. The emitted electrons can be collimated into beams and used to write on, inspect, or irradiate a workpiece.

Optimization of x‐ray sources for proximity lithography produced by a high average power Nd:glass laser

Abstract: We measured the conversion efficiency of laser pulse energy into keV x rays from a variety of solid planar targets and a Xe gas puff target irradiated using a high average power Nd:glass slab laser capable of delivering 13 ns full width at half‐maximum pulses at up to 20 J at 1.053 μm and 12 J at 0.53 μm. Targets were chosen to optimize emission in the 10–15 A wavelength band, including L‐shell emission from materials with atomic numbers in the range Z=24–30 and M‐shell emission from Xe (Z=54). With 1.053 μm a maximum conversion of 11% into 2π sr was measured from solid Xe targets. At 0.527 μm efficiencies of 12%–18%/(2π sr) were measured for all of the solid targets in the same wavelength band. The x‐ray conversion efficiency from the Xe gas puff target was considerably lower, at about 3%/(2π sr) when irradiated with 1.053 μm.

Picosecond excimer laser-plasma x-ray source for microscopy, biochemistry, and lithography

Abstract: At Rutherford Appleton Laboratory we developed a high repetition rate, picosecond, excimer laser system which generates a high temperature and density plasma source emitting approximately 200 mW (78 mW/sr) x ray average power at h(nu) approximately 1.2 KeV or 0.28 KeV < h(nu) < 0.53 KeV (the `water window'). At 3.37 nm wavelength the spectral brightness of the source is approximately 9 X 1011 photons/s/mm2/mrad2/0.1% bandwidth. The x-ray source serves a large user community for applications such as: scanning and holographic microscopy, the study of the biochemistry of DNA damage and repair, microlithography and spectroscopy.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Negative electron affinity group III-nitride photocathode demonstrated as a high performance electron source

Abstract: The need for a high performance (low energy spread 3months per spot, emission stability <1%∕h) electron source continues as part of the development of new e-beam writing and inspection tools. We present measurements from a group III-nitride (indium gallium nitride) photocathode in a demountable vacuum system to measure energy spread, lifetime, and preliminary blanking effects. We show the results of cathodes operating in ultrahigh vacuum (UHV), high vacuum (HV), and oxygen-rich backpressures. Our results show InGaN has a longitudinal energy spread of <300meV in reflection mode, flat lifetimes of 60h per illuminated spot where the yield changes by <10%, and stable emission with typical recoveries within 99% of original photocurrent for all blanking periods and vacuum conditions tested (0.5to10min periods).

Principles of Lithography

Abstract: Lithography is a field in which advances proceed at a swift pace. This book was written to address several needs, and the revisions for the second edition were made with those original objectives in mind. Many new topics have been included in this text commensurate with the progress that has taken place during the past few years, and several subjects are discussed in more detail. This book is intended to serve as an introduction to the science of microlithography for people who are unfamiliar with the subject. Topics directly related to the tools used to manufacture integrated circuits are addressed in depth, including such topics as overlay, the stages of exposure, tools, and light sources. This text also contains numerous references for students who want to investigate particular topics in more detail, and they provide the experienced lithographer with lists of references by topic as well. It is expected that the reader of this book will have a foundation in basic physics and chemistry. No topics will require knowledge of mathematics beyond elementary calculus.

Lithographic apparatus, and device manufacturing method

Abstract: A lithographic apparatus configured to project a patterned beam of radiation onto a target portion of a substrate is disclosed. The apparatus includes a first radiation dose detector and a second radiation dose detector, each detector comprising a secondary electron emission surface configured to receive a radiation flux and to emit secondary electrons due to the receipt of the radiation flux, the first radiation dose detector located upstream with respect to the second radiation dose detector viewed with respect to a direction of radiation transmission, and a meter, connected to each detector, to detect a current or voltage resulting from the secondary electron emission from the respective electron emission surface.

Substrate temperature control system and method for controlling temperature of substrate

Abstract: So as to provide a substrate temperature control system capable of unifying the temperature of the substrate and capable of shortening the temperature elevation time (temperature lowering time), the substrate temperature control system is equipped with a temperature control plate (heating or cooling plate) having a plurality of projections on the surface and serving to set the temperature of the substrate, and a chuck mechanism to fix the substrate in contact to a plurality of the projections by chucking the substrate toward the direction of the temperature control plate.

Micromachined silicon electrostatic chuck

Abstract: An electrostatic chuck is faced with a patterned silicon plate 11, createdy micromachining a silicon wafer, which is attached to a metallic base plate 13. Direct electrical contact between the chuck face 15 (patterned silicon plate's surface) and the silicon wafer 17 it is intended to hold is prevented by a pattern of flat-topped silicon dioxide islands 19 that protrude less than 5 micrometers from the otherwise flat surface of the chuck face 15. The islands 19 may be formed in any shape. Islands may be about 10 micrometers in diameter or width and spaced about 100 micrometers apart. One or more concentric rings formed around the periphery of the area between the chuck face 15 and wafer 17 contain a low-pressure helium thermal-contact gas used to assist heat removal during plasma etching of a silicon wafer held by the chuck. The islands 19 are tall enough and close enough together to prevent silicon-to-silicon electrical contact in the space between the islands, and the islands occupy only a small fraction of the total area of the chuck face 15, typically 0.5 to 5 percent. The pattern of the islands 19, together with at least one hole 12 bored through the silicon veneer into the base plate, will provide sufficient gas-flow space to allow the distribution of the helium thermal-contact gas.