Abstract: A method, useful in fabricating semiconductor integrated circuits, for passivating an undercut formed by etch-back of a silicon dioxide layer under a diverse insulator film is disclosed. The method includes the step of coating the device with a thin, conformal film to a thickness sufficient only to line, without refilling, the lateral walls of the undercut region.

Abstract: Epitaxial regrowth by vapor phase epitaxy of controlled composition semiconductor material in and around undercut regions of a processed heterostructure wafer permits formation of a ridge waveguide capable of active or passive operation. Subsequent material selective and crystallographically preferential etching is employed to form mirror facets on each end of the ridge waveguide.

Abstract: An integrally cast composite piston assembly is disclosed which is effective to carry a ceramic plate in an iron based cap. The assembly comprises a cylindrical piston body, preferably of aluminum, having a crown top, an annular crown side wall with an upper edge, and an annular undercut surface terminating the crown side wall. The undercut surface must make an angle with a plane extending perpendicular to the axis of the piston, the angle being substantially equal to the arc tangent of H/R where H is the median distance of the undercut surface from the plane and R is the median radius of the undercut surface from the axis of the piston. The assembly further comprises the cylindrical iron-based cap disposed on the piston body crown top and having a cap side wall depending about the crown side wall, the cap side wall having an annular lip extending radially inwardly from the cap side wall, the lip having a surface mateable with the undercut surface of the piston body so that there exists a tightly stressed camming relationship between the mateable surfaces as a result of the shrinkage of the piston body upon solidification.

Abstract: This specification discloses a method of molding an article having undercut portions by the use of a plurality of divided cores or core sections combined together to form a unitary mold and having therein through-holes every other of which is different in shape, each of the through-holes having an angle of inclination with respect to a predetermined axis. The method includes the steps of disposing the divided cores on a reference plate to form a divided mold and inserting moving pins into the through-holes, pouring a material between a fixed mold and the divided mold and molding a molded article, and moving the pins inserted in the through-holes of the divided cores constituting the divided mold in the direction of the predetermined axis, whereby of the divided cores, one group of cores having the through-holes of the same shape is first separated from the molded article, and then the other group of cores is separated from the molded article. The specification also discloses an apparatus for carrying out such method.

Abstract: PURPOSE:To prevent generation of damage on a conductive layer and a semiconductor substrate by a method wherein, among multilayer resist films, an undercut etching is performed on the third layer film, the intruding of a high melting point metal film generated by sputtering on the side face of a pattern hole is cut off, and the removal of an unnecessary high melting point metal film conducted when a lift-off method is performed is simplified. CONSTITUTION:A multilayer resist film to be used for a prescribed lift-off is formed. A high melting point metal film 14 is formed using a high melting point metal such as tungsten silicide, for example, and a gate electrode 15 is constituted on a conductive layer having exposed center part. A sufficient undercut 11a is formed on a positive type photoresist 11, and the effect of intruding of the high melting point metal when a sputtering is performed is remarkably relieved. Also, the conductive layer 2 is covered by a titanium film 9, and as said conductive layer 2 is almost not etched, and the possibility of having damage when a reactive ion etching is performed on a silicon nitride film 10 can be removed. Besides, the titanium film 9 and silicon nitride films 10 and 12 of the multilayer resist can be removed easily using an aqueous solution of hydrofluoric acid, the multilayer can be removed, and the unnecessary high melting point metal film 14 adhered to the upper surface of the multilayer resist can also be removed integrally.

Abstract: PURPOSE:To improve the bonding strength between an object, for example, of a metal or ceramic with a synthetic resin, by making holes each having an undercut in an object, and pouring a melted resin into the holes. CONSTITUTION:An object 21 is formed with holes 26 each having an undercut by laser working, and is placed in a mold for molding plastics, and a melted plastic is poured into the holes 26. Thus, the melted synthetic resin 16 fills the undercut sections of the holes 26 of the object through the straight sections thereof to form synthetic resin securing sections 16a, thereby obviating waste of the synthetic resin material.

Abstract: PURPOSE:To cheaply and accurately obtain a molded piece, which has undercut portions and is easy to pigment by a method wherein a core consisting in temporarily forming and shaping particulate matter by a special method is employed together with a molding die in order to mold cold-setting resin. CONSTITUTION:Firstly, molding film 8 is attached onto the surface of the core cavity 4 of a master die 3 by sucking. Secondly, a suction pipe 9 is inserted from an opening 6 into the core cavity 4 and at the same time particulate matter M such as metal powder or the like is charged in the core cavity 4. Thirdly, the opening 6 is sealed with film 10. Fourthly, a portion enclosed with the films 8 and 10 is evacuated by sucking so as to solidify the particulate matter M in order to form a core C. Fifthly, the core C is separated from the master die 3 and then set in a molding die 11. Sixly, liquid cold-setting resin is charged in a product cavity 12 shaped by partitioning with the molding die 11 and the core C in order to set the resin therein. Seventhly, the suction of the suction pipe 9 is stopped so as to collapse the core C and to discharge the particulate matter M from the molding die 11 in order to obtain an aimed molded piece.

Abstract: PURPOSE:To prevent generation of an undercut and defective bead by flattening the tip of an electrode rod, forming a groove at the center of the width thereof and forming a pair of projecting parts to be used as cathode points on both sides of the groove. CONSTITUTION:The tip 11 of a tungsten electrode rod 10 is flattened and a groove 12 centering at the width thereof is provided to the flattened tip. A pair of projecting parts 13, 13 to be used as cathode points are formed on both sides of the groove 12 by the formation of such groove. If TIG arc welding is performed, an arc is generated from the two cathode points by which the adequate dispersion of the arc force is induced. The bead control is thus accomplished by changing the direction for attaching the electrode, applying a magnetic field, etc. over a wide range from small current to large current, by which the welding is accomplished in the mode meeting the purpose of a joint without generation of an undercut and defective bead.

Abstract: PURPOSE:To prepare a radiator tank with complicated undercut portions in the form of a solid molded piece by injecting resin with a low-melting alloy core into a mold and then heating the molded piece to make the core to be melted and flow out. CONSTITUTION:In a radiator tank 3 with the L type liquid injecting hole 1 and the L type inlet pipe 2, undercut portions cannot be taken out by a mold of simple slide core structure. A low-melting alloy core with a specified shape, that has been provided in advance, is fixed in the mold to inject thermplastic resin. The core is taken out together with the molded piece, molded then heated in an oven. The core only is melted and allowed to flow away. Glass fiber charged with polyamide or thermoplastic resin such as noryl etc. is used for the material of the radiator tank. Lead-tin alloy, lead-tin-antimon alloy, etc. are used for the core.

Abstract: PURPOSE:To judge the defectiveness and nondefectiveness of a weld bead at a high speed with high accuracy by picking up the shape of the weld bead from the top surface and side surface, converting the images to the digital information of a gray tone level and obtaining the information on the weld bead. CONSTITUTION:The image of the weld bead welded by a weld zone 8 is picked up from the vertical and horizontal directions by image pickup parts 1, 2, by which the information on the analog images is obtd. Such information on the analog images is supplied separately to an analog-to digital converter 3, by which the information is converted to the information on the respective digital images. A digital image processing part 4 determines the width and height of the beads and the width and length of an undercut and supplies the information on the beads to an arithmetic part 5 for the bead shape. The part 5 judges the defectiveness and nondefectiveness of the weld bead shape. The operation of an automatic welding machine is controlled by the result of the judgement.

Abstract: PURPOSE:To improve the resistance of a guide shoe to seizure and to improve the durability and productivity thereof by providing a recess of a specific depth on the guiding surface of the guide shoe and spraying thermally and depositing a ceramic sprayed layer having specific porosity to the recess. CONSTITUTION:A recess 2 is undercut at 1-30mm. depth on the guiding surface 1 including the contact region of a guide shoe which holds the outside circumference of a blank material for a steel pipe in contact therewith during forming of a seamless steel pipe. A ceramic sprayed layer 3 is thermally sprayed and deposited to the recess 2 to attain the thickness equiv. to the original surface level. The layer 3 is porous with 10-60% porosity. The resistance of the surface 1 of the guide shoe to wear and seizure is thus improved and the durability and productivity thereof are improved.

Abstract: PURPOSE:To make it possible to finish skin material to a preferable shape by pressing heat-melting material tightly to a formed part corresponding to a mold with the use of a plug having a contour form corresponding to the concave and convex parts of the above-described undercut section simultaneous with vacuum molding. CONSTITUTION:For instance, in molding back rest skin material for a car, skin material 10 whose edge is fixed by clamps 3a, 3b on a mold 1 is heated at temperature suitable to vacuum molding and then is molded by sucking with a vacuum pump 9. At that time, plugs 2a, 2b are introduced into a cavity 4 as auxiliary means and mold faces corresponding to the plugs 2a, 2b are sucked and pressed onto undercut sections 5a, 5b to realize molding and then the same procedures are taken to form a deep-drawn part. Thus it is made possible to mold skin material 10 into a perfect undercut, deep-drawn and convex/concave parts with the use of the plugs 2a, 2b.

Abstract: PURPOSE:To prevent generation of an undercut, to increase a welding speed, and to improve a productivity by making a force of a reverse direction operate on a molten metal flow by an electromagnetic force of a moving magnetic field against a molten metal, in case of a horizontal submerged arc welding. CONSTITUTION:In case of a large heat input welding or a high speed welding, a molten pool 5 becomes long and large, and flows 6 in the rear of an arc. A force 11 for obstructing a metallic flow is operated by providing a moving magnetic field generating device 7 just behind an arc fusion zone 10. By this force 11, a good welding state is obtained by preventing generation of an undercut part of a weld zone, and a work efficiency can be improved by further increasing a welding speed.

Abstract: PURPOSE:To form a thin-film having excellent coverage even on the surface of a substrate with a narrow recessed section such as an undercut section by forming a thin-film on the substrate consisting of a semiconductor, etc. with the undercut section, a slender clearance, etc., repeating a process, in which the thin-film is etched through a directional etching method, plural times and forming the thin- film in desired thickness. CONSTITUTION:A CVD SiO2 film 91 is etched through a directional etching method shown by the arrows such as an RIE method in which an Si substrate is positioned between plate electrodes arranged in parallel. A flat section is etched easily through the etching, bu the CVD SiO2 film formed to an undercut section 6 under the end section of a gate electrode 4 is hardly etched because it is shaped by the gate electrode 4. When a CVD SiO2 film 92 is formed again and etched through the directional etching method such as the RIE method, a CVD SiO2 film 9 is formed to the undercut section 6, and the undercut section 6 can be buried. When the undercut section 6 is not buried, a process in which a CVD SiO2 film is shaped and etched through the directional etching method is further repeated.

Abstract: PURPOSE:To facilitate the demolding of a molding with an undercut part from a mold by using an automatic demolding device having a pair of adsorption pads mobile outwardly from the center. CONSTITUTION:An injection molding for a molding 21 is performed and the mold is opened. Then, an automatic demolding device is inserted between a mobile die 20 and a fixed die, a base plate 26 is advanced to fasten an adsorption pad 27 to the molding 21 and with the pulling back of a slide core 25, the diameter of a middle die 24 is reduced while the space of the adsorption pad 27 is widened to remove an undercut part 22 from a flange 23. Then, the base plate 26 is retracted toward the fixed die to release the molding 21 from the mold. This facilitates the releasing of a rubber molding with an undercut part from the mold.

Abstract: PURPOSE:To make possible favorable releasing even when an item having a rib or the like that interferes with the movement of a split mold is produced using a mold having such a structure that the split is moved in the oblique direction of an oblique rod, by dividing the split mold into two blocks, and moving only the block having an undercut section approximately normally to the releasing direction of the molded item. CONSTITUTION:A split mold 38 can be separated downward from a movable mold 22 and is divided into an extrusion block 40 and a slide block 39. The slide block 39 is formed with an undercut section 39a forming an extended section 1a, and the extrusion block 40 is fixed to the tip of a fixed rod 35. Accordingly when releasing is effected, the slide block 39 can be moved on the upper side, where it would not engage with a rib 1b, to a position where the extended section 1a is separated completely from the undercut section 39a, and the molded item 1 can be released below the movable mold 22.

Abstract: PURPOSE:To form a pattern having an inclination with excellent controllability by baking a polyimide group resin on a layer to be processed, applying a photo- resist film and exposing the film, shaping the polyimide group resin to an undercut shape through a development and hard baking and dry-etching the surface. CONSTITUTION:A film to be etched 12 (Al-Si) is evaporated onto an Si substrate 11, and a polyimide group resin (ARC)17 is applied onto the film 12 and baked. A positive type photo-resist 15 is applied, pre-baked and exposed by ultraviolet beams 16. ARC is dissolved to an alkali group developer, the resist is developed, ARC is hard-baked, and patterns for the resist 15 and ARC17 are acquired. When the Al-Si layer 12 is sputtered and etched by using the resist 15 and an ARC film as masks, an exposed section and the resist 15 are etched, and the film to be etched 12 is exposed newly. Accordingly, a pattern with an inclined edge section is formed.

Abstract: PURPOSE:To carry out anisotropic etching to cause no undercut at all, by subjecting a polycrystalline silicon film on a wafer substrate heated at a proper temperature to dry etching by the use of a mixed gas of CCl2F2 and N2 as a reaction gas. CONSTITUTION:The polycrystalline silicon film 201 formed on the silicon oxide film 203 grown on the silicon wafer substrate 202 has the mask 204 of photoresist or other etching-resistant film, the wafer substrate 202 is heated to 30- 100 deg.C, and dry etching is carried out by the use of a mixed gas of CCl2F2 and N2 as a reaction gas. Consequently, improved anisotropic etching having no undercut at the interface 205 between the polycrystalline silicon film 201 and the oxide film 203 can be carried out while keeping high selectivity for the oxide film 203 of the substrate and the mask 204. A flow rate of N2 gas in the total flow rate of the mixed gas is preferably 5-80wt%, and etching pressure is preferably 4-50Pa.

Abstract: The invention relates to a piece part for stiffening and securing a corner joint of toy building blocks which possess undercut longitudinal grooves on their lateral surfaces. In order to be able to produce a stable corner joint which is simple to assemble, the piece part consists of two coherent parts which can be pressed apart radially, each part possessing half of an undercut strip at its two outer surfaces forming the angle of the corner joint and at the edge facing the other part. The two halves together exhibit a maximum cross-sectional dimension which is less than the minimum cross-sectional dimension of the undercut longitudinal grooves on the toy building blocks.

Abstract: PURPOSE:To prevent an airtight material from releasing at the time of mold breaking, by providing an undercut part in a charging groove of the airtight material to be provided at a position surrounding a cavity of a parting surface of a mold. CONSTITUTION:An undercut part 22 is formed in a charging groove 11 of an airtight material, in a mold provided with the groove 11 at a position surrounding a cavity 10 on a parting surface 9 of the mold 7. Then the airtight material 12 is also made into a shape capable of fitting in the undercut part 22.

Abstract: PURPOSE:To form a self-alignment system of an emitter electrode by employing a semiconductor matched in lattice to a substrate as a mask when annealing after ion implantation, thereby suppressing the abnormal diffusion of a P type impurity. CONSTITUTION:A non-doped Al0.3Ga0.9As layer 28, an Al0.4Ga0.6As layer 29, a GaAs layer 30 are grown on an active layer of an N type GaAs substrate 23. This wafer is etched at the layers 30, 29 by Ar reverse sputtering with a photoresist 31 and an SiO2 film 32 as masks. Then, the layer 29 is etched in the undercut shape, and Mg ions 33 are implanted with the photoresist 31 and the film 32 as masks. After the photoresist 31 and the film 32 are removed, a heat treatment is executed to active an Mg acceptor, thereby forming a P type region 34. After ion implantation, GaAs and lattice are matched, and the Al0.4 Ga0.6As, Al0.1Ga0.9As of mostly equal thermal expansion coefficients are used as masks, the abnormal diffusion by the thermal stress of Mg does no almost occur.

Abstract: PURPOSE:To prevent undercut and decrease in strength and to perform automatically multi- layer welding at a high speed by maintaining the specified angle and distance of a torch with and from the outside circumferential end face of a patch, determining the upsetting position of multi-layer welding and controlling the torch. CONSTITUTION:Multi-layer welding is executed while the specified angle and distance of a torch axis with and from the outside circumferential end face of a patch 4 are maintained by controlling the angle theta of inclination with respect to the central axis of a nozzle 7 and the X-axis moving in the direction perpendicular to the central axis. The displacement DELTAZ in the central axial direction of the nozzle where the weld beads of the 2nd and succeeding layers exist between the weld beads of the 1st layer is measured. The measured value DELTAZ is then integrated with the tangential trigonometric function tanbeta of the angle beta at which the outside circumferential end face 6 directed by the welding torch 7 inclines with respect to the central axis of the nozzle 7. The position further from the nozzle 7 in the X-axis direction as compared with the upsetting position of welding set nearer the face 6 of the 1st layer by as much as the length corresponding to the integrated value X is set in the upsetting position of welding near the face 6 in the weld beads of the 2nd and succeeding layers, then welding is executed.

Abstract: PURPOSE:To prevent weld defects in the stage of producing a pipe by laser welding by specifying the irradiating position of the laser, the space in the butt part of a hoop and the numerical range of an upset quantity. CONSTITUTION:The irradiating position (x) of the laser is set at 5-50mm. position forward on a weld line 2 from the intersected point (o) between the line connecting the axial centers of both upset rolls 1 and 1 and the line 2 in the stage of producing the thin-walled small-diameter pipe consisting of more particularly, a stainless steel, heat resisting superalloy, Ti, Zr, etc. by laser welding. The space (d) in the butt part of a hoop 3 is set at 0.01-0.30mm. in the above-mentioned x= 5-50mm. range and further the upset quantity (u), i.e., {(the width of the hoop 3 - the peripheral length of the welded pipe)/(the width of the hoop 3)}X100% is set at 0.05-1%, then welding is executed. The weld defects such as an undercut, blowhole, high temp. crack, etc. are prevented by the above-mentioned method and the quality and production efficiency of the above-mentioned small-diameter thin-walled welded pipe are improved.

Abstract: PURPOSE:To enable to control the etching shape of a material to be processed utilizing active particle concentration distribution in the interelectrode direction by a method wherein only electrodes at the parts installed with the materials to be processed are made to ascend and descend. CONSTITUTION:A cathode 5 is provided in a reaction chamber 3 holding positional relation in parallel with a plane anode 4. A high-frequency electric power source 6 is connected to the cathode 5, and insulated electrically from the reaction chamber 3 by an insulator 7. Moreover, sample stages 9 consisting of an insulator and to be put thereon with materials 8 to be processed are built in the cathode 5, and moreover the sample stages 9 are connected to a sample stage ascent and descent control system 11 through struts 10 consisting of an insulator. When the material 8 to be processed is etched in the condition put on the surface of the cathode 5, anisotropic etching is advanced to etch an Si substrate 2 faithfully to the pattern of an SiO2 mask 1 [the figure (a)]. While, when the material 8 to be processed is etched in the condition lifted up by 10mm. from the surface of the cathode 5 according to the sample stage ascent and descent control system 11, isotropic etching is advanced to form what is called an undercut under the SiO2 mask 1 [the figure (b)].

Abstract: PURPOSE:To make easy molding possible without being charged with a high mold expense, by mounting a resilient body to a nonmolding surface of an undercut working section of a mold, and removing the undercut working section from the inside of the product by physical treatment or chemical treatment after the injection molding. CONSTITUTION:A resilient body sheet 60 is stuck to a nonmolding surface 31 of a core 30 that will be oppositely fitted to a nonmolding surface 53 of an undercut working section 50. A resilient body sheet 61 is stuck to a nonmolding surface 41 of a slide core 40 that is opposite to a nonmolding surface 54 of the undercut working section 50. The undercut working section 50 is made of a sinter produced from a brittle material and the shape of the undercut working section 50 can be lost or collapsed physical or chemically. Thus when molding of a product is effected, the undercut working section is molded, and it is mounted in a mold to form a cavity corresponding to the shape of the product, so that a product with an undercut having a complicated shape can be easily injection molded. Further since resilient body is stuck to a part where an undercut working section is required thereby absorbing the molding error at the undercut working section, high accuracy of molding at the undercut working section is not required.

Abstract: A transducer to measure force in the direction of movement being applied to a segmented sheet formed from narrow pieces of lumber during the passage of the sheet through processing. The transducer is constructed of several typical pieces of wood bonded together to form a small section of the sheet. The central portion of the transducer is undercut to form a trough within which strain gauges are mounted. The undercut protects the gauges from mechanical damage by processing machinery.

Abstract: PURPOSE:To form penetration beads having excellent uniformity without defects such as reinforcement of weld, undercut, etc. by providing projections on the surface of a backing material which contacts with the rear surface of the groove of materials to be welded. CONSTITUTION:A solid backing material for one-side welding is constituted by providing continuous or discontinuous projections 11 to the top surface thereof, i.e., the surface which contacts with the rear surface of the groove of materials 4 to be welded. Projections 11a, 11b of a refractory solid material which contacts with penetration beads 5 are melted by the arc heat of welding and a suitable slag layer 6 is formed by such backing material. The penetration beads having excellent uniformity without defects such as reinforcement of weld, undercut, etc. are thus formed.

Abstract: A mold is made from a flute chimney model having a precision bore, and a chimney is cast from the mold with substantially no shrinkage in bore diameter. The mold can be made from a chimney model having an entire undercut surface thereon, and the chimney cast with substantially no shrinkage in undercut diameter.