Abstract: Patterning of a layer of material that can be etched with gaseous mixture of oxygen, chlorine, and nitrogen as etchant species, such as a chromium or a chromium-containing compound layer, is accomplished by using a patterned organometallic resist, such as a polymer which contains silicon or germanium. Although gaseous mixtures of chlorine and oxygen etch chromium anisotropically. Some undercut of the chromium is still observed. This undercut is controlled or eliminated by adding nitrogen to the gas mixture. Layers of material that have been patterned in this way can then be used for photolithographic masks or reticles, for X-ray masks, for e-beam masks. or for direct patterning of other, underlying layers in semiconductor integrated circuits or other devices.

Abstract: An implantable article having on at least a portion of its exterior surface an integral, as-cast macrotextured surface having pores with undercut edge profiles is provided. The integral, as-cast macrotextured surface is able to be formed on the implantable articles by a modified casting process. As part of a casting process, positive models of the articles to be cast, or parts thereof, are formed by stereolithographic techniques. Cavities or molds, representing negative images of the articles to be cast, are then formed by encasing one or more models in a refractory material. The positive models are then extracted by heating and thus melting the material from which they are made. Thereafter, molten casting material can be poured into the resulting mold to obtain the implantable articles.

Abstract: A method for forming a re-entrant photoresist lift-off profile for thin film device processing of particular utility in conjunction with self-aligned sputtered films, such as permanent magnet ("PM") films, for use in magnetoresistive ("MR") read heads as well as a device made thereby. Photoresist is patterned in a conventional manner upon the thin film layers overlying a suitable substrate and the photoresist is then exposed to a suitable developer resulting in photoresist regions having substantially vertical sidewalls. An electron beam, or other suitable energy source, is then utilized to cross-link (or render relatively insoluble) the upper portion of the positive tone resist image by accelerating a sufficient dose of electrons into the photoresist to a well controlled depth. A second electron beam is then distributed throughout the entire photoresist thickness to render the lower portion of it relatively more soluble in a developer. The resist is then developed for a predetermined time to achieve an undercut in the lower portion of the photoresist.

Abstract: A method of forming a semiconductor structure, and a structure thereof are provided. The method is based on a novel lift-off masking process, and has particular application for forming gate structures for FETs with sputtered metals. After providing a weakly bonded surface layer on the substrate, a multilayer masking layer stack is deposited, and patterned to define an opening with undercut sidewalls. The multilayer masking stack forms a heat resistant mask for nigh temperature deposition of one or more conductive layers, e.g. sputtered metals to form a gate metal stack for a FET. The undercut sidewalls of the mask create a discontinuity in the deposited metal layers. Preferential etching of the deposited metal layers occurs at the discontinuity, resulting in separation of the gate metal structure and the excess metal overlying the masking layers. The weakly bonded surface layer on the substrate controls the adhesion of the overlying masking layers, and allows for the excess metal and the underlying masking layers to be separated from the substrate simply by a liftoff process. The latter is conveniently accomplished by application of an adhesive tape to pull up and remove the layers, separating the weakly bonded surface layer, e.g. an oxide from the substrate. The method provides for a gate structure comprising a multilayer metal stack characterized by smoothly tapered sidewalls, with substantially no undercut in which the taper angle may be controlled. Advantageously, the method avoids ion etch damage to the substrate surface surrounding the gate metal stack.

Abstract: We report a novel fabrication process aimed at reducing the parasitic junction capacitance of AlGaAs-GaAs heterojunction bipolar transistors. The process, named as the Laterally Etched Undercut (LEU) process, physically removes the extrinsic base-collector junction area and results in a cantilever structure. The DC, small-signal, and large-signal performances of the LEU devices are compared to those obtained from the conventional devices.

Abstract: A reversible casing for a fluid-actuated, percussive, down-the-hole drill is provided with a tubular body having an internal surface forming a bore extending along a longitudinal axis. The internal surface has a profile that is a mirror image about a centerline axis perpendicular to the longitudinal axis. The profile is provided with alternating undercut portions and land portions, with a portion of the undercut portions being in an annular scalloped configuration comprising a plurality of longitudinally extending parallel grooves in the internal surface.

Abstract: A diamond-like carbon mask is formed on the surface of the magnetic material for ion-milling the magnetic material into a magnetic pole of a transducer. The mask is formed by depositing a layer of diamond-like carbon over the magnetic material. Successive layers of photoresist, SiO2 and photoresist are applied over the magnetic material. The second layer of photoresist is patterned in the shape of the pole being formed. The exposed insulating layer is etched with an etchant that does not attack the diamond-like carbon, the exposed portions of the photoresist are exposed and removed, and the exposed portion of the diamond-like carbon is etched with an oxygen etchant. The remaining photoresist is washed away to remove the remaining insulating material. In one form of the invention, a layer of SiO2 may additionally be formed over the diamond-like carbon to protect the diamond-like carbon from being affected by any undercut of the photoresist by the oxygen etchant. The SiO2 layer is etched prior to etching the diamond-like carbon. The mask is used to ion mill the magnetic material to the desired pole.

Abstract: Microcoils are less efficient due to the scale effect, but if a permanent magnet is used, the result is a quite scale-independent magnetic field strength. 2D-microstructures of various shapes have been etched out from a 1 /spl mu/m aluminium thin-film. These structures are locally released from the wafer by undercut etching. By sending an electric current through them, a Lorentz force component is induced in some sections, resulting in deformation of the thin-film structure. First, different shapes of 1-turn coils are presented. The arrangement of vertical and parallel magnetic field is discussed. Micromachine fabrication using IC thin-film, lithography and etching technology is presented. An x-y table was built as an application example for the use of Lorentz force in micromachines. For protection and the ease of handling the microactuators are packaged into a standard IC case. As examples of further applications of Lorentz force actuators, a micromirror device, a ciliary motion system and microrelays are discussed.

Abstract: A channel layer made of n-type GaAs doped with Si, a hole absorption layer made of InGaAs having a valance band higher in energy level than that of GaAs, and an undoped layer made of GaAs are formed sequentially on a semi-insulating substrate made of GaAs. A gate recess region having a pair of sidewall portions each consisting of an upper sidewall composed of the undoped layer and a lower sidewall composed of the hole absorption layer is formed on the channel region. The channel region is exposed in the gate recess region. An indent having an undercut configuration is formed in the lower sidewall of the gate recess region. A gate electrode is formed to extend over a stepped portion composed of the sidewall portion of the gate recess region closer to a drain electrode.

Abstract: This paper investigates the plasma etch characteristics of electron beam processed photoresist. A standard positive novolak photoresist, as well as an advanced deep-UV photoresist, are evaluated. Etch characteristics are determined for an oxide etch application. Etch selectivity of the photoresist is determined as a function of electron beam dose. Photoresist undercut and wall slope variation are also determined as a function of dose. The performance of the electron beam processed photoresist is evaluated for line and via formation. The etch characteristics of the electron beam processed photoresist are compared with the etch characteristics for untreated and thermally processed photoresist. In most cases there is an improvement in photoresist profile integrity with increasing electron beam dose. Interaction of the processed photoresist with the plasma chemistry, and its effect on post process removal, are also presented. Finally, a process model is presented for using the electron beam process in current production plasma etch applications.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: A machining apparatus (20) for deep fillet rolling the undercut radii of a crankshaft (22) includes an adjustable support means or workholder (24) and a rolling tool assembly (26).

Abstract: In a drilling device for producing drilled holes with an undercut, in particular in facing panels of stone, ceramics, concrete or similar materials a drive motor of a drilling shaft is mounted so as to swivel, is displaced outward by a sloping surface, and is driven by a lead screw gear unit to perform a precession movement.

Abstract: The clamp comprises a frame insert (16) connected by a hinged joint piece (18) to the opposite face of a hinge plate support (7). The insert fits into a recess (10) with undercut sides (12) in the frame (1). The undercut face of the frame is clamped between the hinge plate support and the insert when brought together by a screw (25). The clamp is made in one piece by extrusion so that the holes through all three parts for the screw are correctly positioned and aligned when the distance between the insert and support faces is equal to the thickness of the recess undercut face.

Abstract: The Long Duration Exposure Facility (LDEF) has provided an excellent opportunity to understand the nature of directed atomic oxygen interactions with protected polymers and composites. Although there were relatively few samples of materials with protective coatings on their external surfaces on LDEF which were exposed to a high atomic oxygen fluence, analysis of such samples has enabled an examination of the shape of atomic oxygen undercut cavities at defect sites in the protective coatings. Samples of front-surface aluminized (Kapton) polyimide were inspected by scanning electron microscopy to identify and measure crack defects in the aluminum protective coatings. After chemical removal of the aluminum coating, measurements were also made of the width of the oxidized undercut cavities below the crack defects. The LDEF flight undercut cavity geometries were then compared with Monte Carlo computational model undercut cavity predictions. The comparison of the LDEF results and computational modeling indicates agreement in specific undercut cavity geometries for atomic oxygen reaction probabilities dependent upon the 0.68 to 3.0 power of the energy. However, no single energy dependency was adequate to replicate flight results over a variety of aluminum crack widths.

Abstract: PURPOSE:To obtain a resin forming mold for molding a resin molded piece wherein a part of a product having a rib is forming an undercut. CONSTITUTION:In order to mold a molded piece W in which a base of a rib molding part 5a of a cavity 5 forms an undercut Ur, a slant push-up core 4 which moves to a slant front part with respect to a movable mold 2 by interlocking the front protrusion of the molded piece W is provided for heightening degassing effect at the rib molding section 5a, and treating the undercut when the molded piece is to be pushed out. In the slant push-up core 4, a slide pin 15 to be energized by a spring is provided. The tip of it appears and disappears in accordance with the back-and-forth movement of the slant push-up core 4 so as to treat other undercut Uo of the molded piece.

Abstract: A screw head for an injection molding machine is mounted to a distal end portion of a screw, and includes a trunk portion and a screw portion, and an undercut portion formed between the trunk portion and the screw portion, wherein a relationship between a shaft diameter ~ of the undercut portion and a nominal diameter ~ of the screw portion is defined as: 0.74f ~ e ~ 0.85f and a relationship between the nominal diameter ~ of the screw portion and a radius ~ of curvature of the undercut portion is defined as: 0.5f ~ r

Abstract: PURPOSE:To eliminate the need for deburring in a post stage by rotating plural molding members around the central axial line of molded goods after the end of pressurization, then retreating the members from a die space. CONSTITUTION:Material powder 71 is press molded by actuating upper and lower punches 35, 37 and upper and lower second punches 41, 47. Burrs P are generated at the butt surfaces at the front ends of cam die plates 31, 33. These cam die plates 31, 33 are simultaneously rotated at a prescribed angle theta. The upper and lower punches 35, 37 are slightly retreated at the time of rotation to decrease the stresses acting on the cam die plates 31, 33 so that the cam die plates 31, 33 easily rotate. Consequently, the burrs P formed on the outer periphery of an undercut part 51 are removed. The cam die plates 31, 33 are rotated in a backward direction and are returned to their home positions after the removal of the burrs P. The molded goods are then taken out by retreating the die plates.

Abstract: PURPOSE:To improve a weight balance and to reduce the cost by molding monolithically a fan having a construction wherein a fitting plate of a hat type and a ring-shaped air-straightening and reinforcing plate being opposite thereto are con nected by a plurality of vanes juxtaposed radially. CONSTITUTION:This fan has a construction wherein an upper-end flange 1b of a fitting plate 1 of a hat type and a ring-shaped air-straightening and reinforcing plate 4 are connected by a plurality of vanes 2 arranged in radial directions. As for a die for molding this monolithically, a cavity insert die 26 is fitted to a stationary template 20 and a core insert die being opposite thereto is fitted to a movable template 21. A notch 35 for molding the reinforcing plate 4 is embedded around the base end of the core insert die and made movable forward and backward. Outside of the core insert die, a plurality of vane insert dies (core slides 24 and cavity slides 23) for molding discrete vanes 2 are provided. Locking blocks 25 are fixed to the movable template 21 and a stationary die plate 28 and the undercut parts thereof are made to engage with the vane insert dies 23 and 24. After molding, the vane insert dies 23 and 24 are drawn outward in such a manner that a time lag occurs in conformity with the movement of a movable die.

Abstract: PURPOSE:To provide a slide mold structure which is compact without necessity of a large-scale mold operating mechanism in the case of releasing a molded form having double undercut parts and in which a cost, a manhour required for manufacturing molds can be reduced and an effective mold opening timing can be obtained. CONSTITUTION:A master slide 2 which moves in a direction capable of mold releasing from a first undercut part 6b in the case of moving a slide mold and has a guide protrusion 2a inclined to the moving direction engages to hold a slave slide 3 which has a guide groove 3a to be slidably engaged with the protrusion 2a of the slide 3. A stopper 4 which has a step 4a having an angle and a height in which the slide 3 is separable from a second undercut part 6c engages a step 4a with a recess 3d formed in a bottom of the slide 3.

Abstract: PURPOSE:To enable a molded product having an undercut part to be simply vacuum formed CONSTITUTION:A sheet material is vacuum formed to be pinched by pressure between a top tool 2 and a bottom tool 3 of a vacuum forming apparatus 1 Further, an insert die 7 for molding an undercut part is protruded from a tool surface 4 An undercut part 20 is molded between the insert die 7 and an recess part 11 for molding the undercut opposed to the insert die 7

Abstract: During implementation of a chemically amplified I-line negative resist (INR) into the eight- inch-wafer manufacturing line at IBM's facility in Essex Junction, Vermont we found that the resist profiles were being undercut during development on silicon-nitride surfaces. The undercut was attributed to a `poisoning' of the photoacid generated in the resist during exposure by the nucleophilic characteristics of the silicon-nitride surface. A second-generation negative resist has since been formulated by IBM, which greatly reduces these undercut effects but does not eliminate them. This newer version of INR is referred to as INR2. To further understand the effects of silicon nitride on the I-line negative-resist profiles, we used Prolith/2 (v3.05)3 to model the underlying stack and evaluate the performance of INR2. Silicon monitors with oxide and different nitride thicknesses were patterned with INR2 using 4-Mb DRAM manufacturing ion-implant block masks and associated photo processing. The results indicated that the undercut observed by this chemically amplified negative resist on silicon nitride was not only chemical in nature, but related to the optical properties of the nitride substrate. Simulation results obtained using Prolith/2 are give and compared with resist profiles obtained from wafers processed with INR2; the accuracy of the Prolith/2 model to predict slope profiles for INR2 is also discussed.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: PURPOSE: To easily and highly accurately form continuous undercut part along the peripheral edge of the opening part of a box-like molded article CONSTITUTION: A projecting part 14C, which fits to a dovetail provided on the inclined plane of a vertically moving movable core block 8, is provided on a side slide core 14 Further, in inclined through hole 27A, into which an angular pin 25 slantly fixed to a movable retainer plate 4 interlocking with the movable core block 8, is provided on a corner slide core 26 COPYRIGHT: (C)1996,JPO

Abstract: of EP0668062An implantable article having on at least a portion of its exterior surface an integral, as-cast macrotextured surface having pores with undercut edge profiles is provided. The integral, as-cast macrotextured surface is able to be formed on the implantable articles by a modified casting process. As part of a casting process, positive models of the articles to be cast, or parts thereof, are formed by stereolithographic techniques. Cavities or molds, representing negative images of the articles to be cast, are then formed by encasing one or more models in a refractory material. The positive models are then extracted by heating and thus melting the material from which they are made. Thereafter, molten casting material can be poured into the resulting mold to obtain the implantable articles.

Abstract: A device for temporary attachment to goods having a flexible material for the protection thereof against theft. The device includes a side with a recess formed therein, the recess having a given shape. The recess is bounded laterally by undercut side walls. A part having a shape substantially complementary to the recess of the member and being adapted to be inserted in the recess. The recess of the member and the part defining a space therebetween for receiving and clamping a layer of flexible material of the goods to be protected against theft without penetrating through the flexible material. The recess and the part are provide with mutually cooperating means for releasably locking the part in the recess of the member with the layer of material clasped in between.

Abstract: PURPOSE:To provide an injection forming mold with which an undercut is released from a slant core smoothly and assuredly, and an ejection stroke is minimized so as to shorten a molding cycle time. CONSTITUTION:A slide core 20 is provided near an undercut of a slant core 12. At the side of the undercut of the slide core 20, a side ejector pin 21 protrudes. Further, a spring 22 is provided at an opposite side of the side ejector pin 21 of the slide core 20. The slide core 20 is slid by the pressing force of the spring 22 and an undercut 31 of a molded piece is projected by the ejection of the side ejector pin 21.

Abstract: PROBLEM TO BE SOLVED: To avoid the concentration of an electric field effectively by forming a gentle shape of the edge part, i.e., the shoulder part of a trench forming part in a semiconductor substrate. SOLUTION: An oxidation-resistant film 21 is formed on the surface of a semiconductor substrate 11 through an oxide film 15 so called a pad oxide film. Then, a trench 13, which is made in the semiconductor substrate 11 penetrating the oxidation-resistant film 21 and the oxide film 15, is formed. Thereafter, an undercut part 15u, which is expending with a width (d), is formed on the oxide film 15 by isotropic etching from the edge part of the trench 13 to the outside. Furthermore, an oxide film with a thickness (t) is formed on the inner surface of the trench 13 including the exposed surface of the semiconductor substrate exposed by the undercut of the oxide film. Thus, a trench- isolated separated semiconductor device is constituted. COPYRIGHT: (C)1997,JPO

Abstract: PURPOSE:To enhance the strength of a slide mold and to easily form the slide surfaces of a movable mold and the slide mold by forming a through-hole to the slide mold and fitting a mold member having a rib forming recessed part in the through-hole to form the rib of a resin molded object. CONSTITUTION:A drive means moving a slide.mold 40 to a movable mold 33 from the undercut part 41b of a resin molded object is provided. A mold member having a rib forming recessed part 43c provided to the leading end surface thereof by the through-hole 33d formed to the slide mold 40 so as to pierce in the same direction as the predetermined direction of the slide mold 40 and the rod like member fitted in the through-hole 33d in a freely slidable manner and fixed to the movable mold 33 is provided. The through-hole 33d is formed so that the distance between the end part on the side of the undercut part 41b of the through-hole 33d and the rib forming recessed part 43c becomes larger than the moving quatity of the slide mold for retracting the slide mold 40 from the undercut part 41b.

Abstract: PURPOSE: To delay and transmit momentum to a ball so as to damp audible vibration by providing a damping means for damping audible vibration generated when a front wall part collides with a golf ball on the front wall part of the front end of the main recessed part. CONSTITUTION: A main body part 11 of a head 20 partitions a heel 12, a toe 13, an upper surface 14 and a sole 15, and the main body part 11 further partitions a face 16 inclined upward and backward. The main body part 11 partitions two recessed parts intersecting each other. An undercut recessed part 22 is formed in such a shape as to be bulged outward from the main recessed part 21 to at least three of the top surface 14, the sole 15, the head part 13 and the heel part 12, or formed in such a manner as to position immediately after the front wall part 17. The part bulged toward the upper surface 14 and the part bulged toward the sole 15 of the undercut recessed part 22 are elongated in such a manner as to be extended toward the toe heel direction extending over the most part of the whole length of the head 10.

Abstract: PURPOSE:To prevent the partial deformation caused by molding shrinkage of an instrument panel of a car subjected to injection molding. CONSTITUTION:A resin instrument panel 1 having an undercut structure having an air blowoff port part 1a which has attaching holes 2 for supporting an external part formed to the upper and lower wall surfaces thereof in a piercing state provided to the end part thereof is produced by injection molding. The blowoff port mold forming the inner surface of the air blowoff port part 1a is equipped with a pair of upper and lower extrusion molds 4 and the extrusion guide allowing both molds to approach and separate in an up-and-down direction. Projections 4a forming the attaching holes 2 are provided to the extrusion molds 4 and protruding parts 4b are integrally provided thereto in the panel molding shrinkage direction in the vicinity of the projections 4a. The molding shrinkage force F of the instrument panel generated when the instrument panel subjected to injection molding is extruded by the extrusion molds 4 to be demolded is dispersed by the engagement of the projections 4a and the attaching holes 2 and the engagement of the protruding parts 4b and recessed parts 7 to prevent the deformation of the attaching holes 2.