摘要:
Method and apparatus which uses harmonic cantilevers, such as used in atomic force microscopy, to detect variations in the attractive and repulsive forces on a solid surface as a result of macromolecular binding, for example, hybridization of a single stranded DNA molecule attached to the surface with another DNA molecule. The complexed macromolecule is less flexible than an uncomplexed molecule. It will typically have more negative charge due to amino acids or DNA monomers. Both stiffness of the surface and the attractive capillary forces will change after binding and may be detected. The present methods and materials enable ultraflat surfaces for the macromolecule deposition, and may include the use of a gold-coated mica substrate and a self-assembling monolayer.
摘要:
A harmonic cantilever for use in a tapping-mode atomic force microscope includes a cantilever arm and a probe tip. The cantilever arm has a shape selected to tune the fundamental resonance frequency or a resonance frequency of a selected higher order mode so that the fundamental and higher-order resonance frequencies have an integer ratio or near integer ratio. In one embodiment, the cantilever arm can be shaped to tune the fundamental resonance frequency. Alternately, the cantilever arm can include a geometric feature for tuning the resonance frequency of the fundamental mode or the selected higher order mode. An imaging method using the harmonic cantilever is disclosed whereby signals at the higher harmonics are measured to determine the material properties of a sample. In other embodiment, a cantilever includes a probe tip positioned at a location of minimum displacement of unwanted harmonics for suppressing signals associated with the unwanted harmonics.
摘要:
A bimorph spiral which exhibits a shape-altering response to thermal radiation and is dimensioned to have a focussing effect on light, such as a visible light, by acting as a quasi-Fresnel element. The focussing effect varies as the shape of the bimorph spiral changes due to absorption of thermal radiation. An array of such bimorph spirals can be used for efficient, high-resolution and rapid uncooled photothermal spectroscopy.
摘要:
An improved optical photolithography system and method provides predetemined light patterns generated by a direct write system without the use of photomasks. The Direct Write System provides predetermined light patterns projected on the surface of a substrate (e.g., a wafer) by using a computer controlled component for dynamically generating the predetermined light pattern, e.g., a spatial light modulator. Image patterns are store in computer and through electronic control of the spatial light modulator directly illuminate the wafer to define a portion of the polymer array, rather than being defined by a pattern on a photomask. Thus, in the Direct Write System each pixel is illuminated with an optical beam of suitable intensity and the imaging (printing) of an individual feature is determined by computer control of the spatial light modulator at each photolithographic step without the use of a photomask. The Direct Write System including a spatial light modulator is particularly useful in the synthesis of DNA arrays and provides an efficient element for polymer array synthesis by using spatial light modulators to generate a predetermined light pattern that defines the image patterns of a polymer array to be deprotected.
摘要:
A scanning probe microscope is used to fabricate a gate or other feature of a transistor by scanning a silicon substrate in which the transistor is to be formed. An electric field is created between the cantilever tip and the silicon substrate, thereby causing an oxide layer to be formed on the surface of the substrate. As the tip is scanned across the substrate the electric field is switched on and off so that an oxide pattern is formed on the silicon. Preferably, the oxide pattern is formed on a deposited layer of amorphous silicon. Extremely small features, e.g., a MOSFET gate having a length of 0.2 .mu.m or less can be fabricated by this technique.
摘要:
A deflection sensor for a microcantilever includes two sets of interdigitated fingers, one (reference) set being attached to the substrate from which the microcantilever extends and the other (movable) set being attached to the tip of the microcantilever. Together the interdigitated fingers form an optical phase grating. The deflection of the microcantilever is measured by directing a light beam against the optical phase grating and detecting the intensity of the reflected light in the first (or other) component of the resulting diffraction pattern. As the microcantilever deflects, the reference and movable fingers move relative to one another creating large variations in the intensity of the zeroth and first order components of the diffraction pattern. To eliminate "1/f" noise the deflection of the microcantilever can be measured using an AC signal.
摘要:
A device for detecting the presence of particles and irregularities on the surface of a semiconductor wafer or other substrate includes a plurality of cantilevers formed on a semiconductor substrate and a means of detecting the deflection of each of the cantilevers. The cantilevers may, for example, be formed in rows and separated by selected distances. The entire substrate is then scanned over the surface to be examined, in a raster pattern, for example, and the deflection of the individual cantilevers is monitored.
摘要:
A photolithography system includes a plurality of cantilevers, preferably formed in a silicon wafer. Each cantilever includes a tip located near the free end of the cantilever and a waveguide which extends along the length of the cantilever and intersects the tip. An aperture is formed at the apex of the tip so that light travelling through the waveguide may exit the tip. A light switch is included in the waveguide to control the passage of light to the tip of the cantilever.The array of cantilevers is positioned adjacent a wafer which is to be lithographed, in the manner of an atomic force microscope operating in the attractive mode. Each cantilever is a compound structure, including a thick portion and a thin portion, the latter having a preselected mechanical resonant frequency. The cantilevers are caused to vibrate at their resonant frequency and the actual frequency of vibration is detected and used to maintain a uniform spacing between the tip of the cantilever and the surface of a photoresist layer which is to be exposed. Preferably, both the vibrational motion and the control of the tip-photoresist spacing are effected by means of a capacitive plate located adjacent the cantilever.The cantilever array is scanned over a photoresist layer on the wafer, preferably in a raster pattern, and the individual light switches are operated so as to expose individual pixels on the photoresist layer.
摘要:
A integrated mass memory device is formed by combining a piezoelectric bimorph cantilever (214) with a recording surface (212) having a number of storage locations to and from which digital information is transferred using a scanning tunneling microscope or an atomic force microscope mode of operation. Controls circuits (240) are provided for controlling the scanning of the recording surface (212) and for writing and reading information into and from the recording surface. An image storage system stores images captured from an optical sensor using piezoelectric bimorph cantilevers for reading and writing digital information on recording surfaces.
摘要:
A sample and selective support structure mounted on a platform in a scanning tunneling microscope includes a double spring support with the springs overlapped to reduce overall length of the support. In a preferred embodiment, a rigid support structure supports a first platform. A second platform is positioned around and spaced from the first platform and includes a plurality of support members extending therefrom. A first set of springs is attached to the rigid support structure and to the second platform for supporting the second platform, and a second set of springs is attached to the second platform and to the first platform for supporting the first platform. By attaching the second set of springs to the rigid members extending from the second platform, the first and second sets of springs can be overlapped, thereby reducing the overall length of the spring support without reducing the effective length of the springs. A lock mechanism is provided for locking the first and second platforms when not in use, and includes a rod that engages holes in two members depending from the first and second platforms. The lock mechanism further includes first and second rigid arms pivotally attached to the rod and supported whereby the rigid arms extend from and retract to the rod when the rod is translated. When the rigid arms are extended from the rod, the arms engage lock mechanisms depending from the first platform, thereby achieving a rigid lock in six axes of motion.