Abstract: In wet anisotropic etching, the etched profile of undercut convex corners depends on the type of etchant. A considerable amount of research has been carried out to explain this convex corner undercutting and to identify the orientation of undercut planes. However, it is not clearly understood why differently shaped undercut fronts appear with different etchants. Moreover, there has been no descriptive explanation regarding the distinct shape of the undercut convex corner in both KOH and TMAH. In this work, corner undercutting on the surface of a Si{100} wafer is thoroughly investigated. The undercutting behavior is examined for two different kinds of etchants (KOH and TMAH). The study is performed by analyzing the etching characteristics of different kinds of convex corners on the mask patterns. One type of corner in the mask design is formed by directions, while other types are formed by the intersection of different directions, which shapes the undercut convex corner profile. Furthermore, the appearance of etchant-dependent beveled directions at convex corners is clearly explained using the contour plot of the etch-rate data of a silicon hemisphere.

Abstract: A method for creating undercut features in a wax pattern in an investment casting process is disclosed. The method comprises designing a tooling that includes a mold for an object with an aperture and a core corresponding in size and shape of the aperture. Then, the mold is used to injection mold a pattern for the object, wherein the pattern includes an opening corresponding to the aperture. Next, a plug from the core of the tooling is injection molded using the mold. The plug is press-fitted into the opening of the pattern and the opening of the pattern is sealed with the plug.

Abstract: A composite of metal and resin includes a metal piece and a resin piece combined with the metal piece. A surface of the metal piece defines a plurality of micropores including an upper portion and a lower portion, the upper portion is communicated with the lower portion, and an aperture of the lower portion is larger than an aperture of the upper portion. The lower portion includes an undercut portion. The resin piece is partially embedded into the lower portion and the upper portion of the micropores. A method of manufacturing the composite of metal and resin is also provided.

Abstract: Disclosed is a detection and quality judgment method for strip steel weld surface appearance. The surface of a weld is scanned by a linear laser; the values such as weld stack height, depression, undercut and misalignment are calculated according to scanned data; the quality of the weld is judged according to the values; accordingly, the surface appearance quality of the weld is judged continuously. The method has the advantages that the surface appearance of the weld can be detected fast and evaluated fast, fast continuous operation of an acid tandem rolling is ensured, and breakage of strip steel is prevented.

Abstract: This article describes automated identification, classification, division and determination of release direction of complex undercut features of die-cast parts. The proposed system uses the concepts of visibility and accessibility to identify undercut features from a B-rep model of a die-casting part. The undercut features are then classified using a rule-based algorithm. Thereafter, the identified complex undercut features are separated into simple ones. Finally, the release direction for each simple undercut feature is determined and those having common release direction are grouped. The proposed system is implemented on case study die-cast parts, and the results are verified. This article would help bridge the design-manufacturing integration gaps in the die-casting process.

Abstract: Described are a mold and molding process for manufacturing devices and containers that are scalable, modular, and lockable laterally and vertically with other like devices or containers. The mold is formed with a cup mold and top end mold sections specially designed to allow for molding and demolding a container with an undercut. The cup mold includes, on a vertical wall, one or more undercuts. Multiple undercuts may further form tongues with undercuts each of which forms a groove with undercuts on the molded article, and/or one or more grooves with undercuts each of which form a tongue with undercuts in the molded article. Molding and Demolding of the article with undercuts is further enabled by utilizing an improved method of molding said article with an undercut, and demolding said article from the mold once it is molded, by improvements to each stage of the molding process, including the preform stage, the conditioning station stage, the blow stage and the release stage.

Abstract: Non-conventional process like Photochemical Machining (PCM) is found to show a promise for machining very thin metal components. In the present study, the effect of various selected parameters such as time of etching, temperature of etchant and concentration of etchant on material removal rate, undercut in PCM of phosphor bronze has been investigated by using multi-objective grey relational analysis and their optimal conditions are evaluated. Full factorial (L27) orthogonal array (DoE) has been used to perform the experiments. GRG value indicates most significant parameters affecting the PCM process. The above factors are selected on the basis of effect - cause analysis and literature survey. Mathematical models relating to the machining performance and machining parameters have been formulated. Optimal settings for each performance measure have also been obtained. The results obtained after conference test prove that improvement in the quality will take place is if the setting of parameters are done at optimum level predicted by multi-objective grey relational analysis. The ANN model is prepared to predict the result by training neural which can be compared with actual experiments to confirm the satisfactory performance during the experimentation.

Abstract: This paper presents the issues in machining of copper using Photochemical Machining (PCM). Twenty-seven experimental runs base on full factorial (3 3 ) Design of Experiments (DoE) technique can perform. The control parameters can consider the etchant concentration, etching temperature and etching time. The response parameters were Undercut (Uc) and the Surface roughness (Ra). The effects of control parameters on undercut and surface roughness can analyze using Analysis of Variance (ANOVA) technique and their optimal conditions can evaluate. An optimum surface roughness can observe at particular etching temperature, an etching concentration and etchings time. The minimum undercut (Uc) can observe at the particular etching temperature, etching concentration and etching time.

Abstract: Tungsten inert gas (TIG) welding which uses a non-consumable tungsten electrode and an inert gas for arc shielding, is an extremely important arc welding process. The aims of this research project are to find optimization parameters in weld bead using TIG. Semi-automatic TIG was developed to ensure the success of this research project. Samples are produce in single bead and padding bead on top of substrate (base metal) in horizontal position. Substrate material is from Mild Steel AISI 1018 while wire filler ER70S-6 has a diameter of 0.8 mm and Tungsten electrode EWth-2 (2% Thorium, Red) has a diameter 2.4mm. Argon is used as shielding gas for this research project. Parameters such as Ampere (A), Travel Speed (mm/s) and Wire Feed Rate (mm/min) has been determined and selected as factors that can influence the weld bead result. Taguchi orthogonal array L9 (Minitab 16) was used to determine the amount of runoff and the analysis of samples. The result for surface roughness was found to be better with an average value of Ra 2.96 μm for single bead and Ra 3.08 μm for padding bead when compared to the work of other researchers. Surface hardness has also shown improvement from this research project. Analysis result shows that the travel speed of the torch has the greatest effect on surface roughness followed by wire feed rate and ampere. Dye Penetrant Inspection (DPI) interpretations of the nearest Optimize level shows no cracks or porosity occurring on top of the bead surface. Defects only happen at the undercut weld due to improper start-up of the welding. For future study other parameters and optimization technics need to be considered. The parameter combination must reflect safety, environment issue and reasonable factors.

Abstract: The present invention relates generally to semiconductor devices and more particularly, to a structure and method of forming a contact silicide on a source-drain (S-D) region of a field effect transistor (FET) having extensions by using an undercut etch and a salicide process. A method of forming a contact silicide extension is disclosed. The method may include: forming an undercut region below a dielectric layer and above a source-drain region, the undercut region located directly below a bottom of a contact trench and extending below the dielectric layer to a gate spacer formed on a sidewall of a gate stack; and forming a contact silicide in the undercut region, the contact silicide in direct contact with the source-drain region.

Abstract: Suspended structures are provided using selective etch technology. Such structures can be protected on all sides when the selective undercut etch is performed, thereby providing excellent control of feature geometry combined with superior material quality.

Abstract: Advances in micro and nano fabrication technologies for MEMS require high-level measurement techniques with regard to sampling and sensitivity. For this purpose at the Institute of Microtechnology (IMT) highly sensitive piezoresistive 3D force sensors based on SU-8 polymer have been developed. In this paper we present an improved micro fabrication process for a double-sided micro structured design. The sensors are produced by multilayer processing techniques such as UV lithography and coating methods. The double-sided micro structured design demands a photoresist application method which simultaneously features a top side structuring and a casting from a mold. We use a new micro molding process to meet the demands. The micro fabrication technology is described, focusing on the development of the molding structure for shaping of the bottom side and a capable release process for the detachment of the molded structures. The fabrication process of the SU-8 mold layer is optimized to fabricate molding structures with heights from a few μm up to 350 μm. Therefore different SU-8 formulations, namely with classification numbers 5, 25, 50, and 100, have been used. The fundamental limitations for the mold design result from the lithography process, which defines the smallest lateral resolution, and from the characteristics of a molding process, e.g. the impossibility to realize an undercut. To allow for reliable release, the molding structures have to be coated with a sacrificial layer. Silicon nitride is deposited onto the substrate with accompanying monitoring of the deposition temperature during the PECVD process.

Abstract: The invention discloses an orthogonal spiral cutting edge type ellipsoidal ball milling cutter for machining a complicated curved surface, and relates to an ellipsoidal ball milling cutter, aiming to solve the problems that a ball milling cutter is low in machining efficiency during machining of the complicated curved surface, the surface quality is lowered, a tool is short in service life due to severe abrasion of a cutting edge, an annular milling cutter is large in undercut quantity during the machining of the complicated curved surface, the application occasions are limited, and the precision of the machined surface is lowered due to tool abrasion of the milling cutter during the machining of a workpiece in the prior art. The ellipsoidal ball milling cutter comprises a cutter handle part and a cutter bit part, and is a cylinder, wherein the cutter handle part is positioned at one end of the cylinder; the cutter bit part is positioned at the other end of the cylinder and comprises an end edge part and a peripheral edge part; the end edge part, the peripheral edge part and the cutter handle part are sequentially arranged from one end of the cylinder to the other end of the cylinder; one end surface positioned at the cutter bit part of the cylinder is a hemi-ellipsoidal. The orthogonal spiral cutting edge type ellipsoidal ball milling cutter for machining the complicated curved surface is applied to the field of machining.

Abstract: A watercraft includes a molded hull in the form of a single-piece hollow plastic structure, and the hull defines a recess having an interior. An insert is also provided that defines an opening and is attached to the hull. The insert is positioned with respect to the recess such that the opening in the insert communicates with the interior of the recess, and the insert cooperates with the recess to define an undercut that accommodates a portion of a hand of a user.

Abstract: J. Tušek, A. Skumavc, D. Klobčar, Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia K. Pompe, TKC-Technology Consulting Center, Ljubljana, Slovenia This paper presents the use of two welding processes for the refurbishment of damaged industrial tools. In the first part the problem is presented followed by the comparison of GTAW and laser welding in terms of repair welding of damaged tools. The macrosections of the welds show the difference between both welding processes in repairing of damaged tools. At the conclusion the main findings are presented. In many cases it is useful to use both welding processes in order to achieve better weld quality and to make welding more economical. The order of the technology used depends on the tool material, the use of the tool and the tool damage.

Abstract: Methods of forming an integrated circuit device include forming an interlayer dielectric layer on a first surface of a semiconductor substrate and then forming an interconnect hole that extends through the interlayer dielectric layer and into the semiconductor substrate. A first sidewall spacer layer is formed on a sidewall of the interconnect hole. The semiconductor substrate at a bottom of the interconnect hole is isotropically etched to define an undercut recess in the semiconductor substrate. This etching step is performed using the first sidewall spacer layer as an etching mask. The interconnect hole and the uncut recess are then filled with a through-via electrode. A second surface of the semiconductor substrate is removed for a sufficient duration to expose the uncut recess containing the through-via electrode.

Abstract: A method is provided for fabricating an ultra short gate length thin film transistor. A plurality of layers is deposited on a substrate including a refractory metal and a first and second photosensitive material. The second material is sensitive to longer wavelength optical radiation than the first material and the first material is not soluble in chemicals used to develop or strip the second material. A source contact pattern is defined in the second material to mask the first photosensitive material. The first material is processed to produce an undercut of the first material with respect to the second material. A metal layer is deposited at a normal incidence on the second material and an exposed portion of the refractory metal. The second material is removed. Exposed portions of the refractory metal corresponding to the undercut of the first material are removed to form a gap in the refractory metal.

Abstract: Presented in this work are the results of a masters assignment at the NanoElectronics research chair of the University of Twente, the Netherlands. The goal of this assignment was to develop a magnetic organic field-effect transistor, which can be used for spin accumulation measurements. The organic layer is the polymer poly(3-hexylthiophene). In such a device, the injection of a spin polarised current is achieved by using a ferromagnetic material for both the source and the drain contacts. Both a back-gated and a top-gated geometry was developed. For a back-gated magnetic O-FET device, the fabrication process is short and uncomplicated. However, this geometry has disadvantages when compared to a top-gated magnetic O-FET device. Experiments have been designed and realised to develop the fabrication recipe, focussing on obtaining high-quality magnetic electrodes without ridges at the edge of the electrodes. This is achieved by using an image reversal photoresist with a pronounced undercut, in combination with lift-off photolithography. Furthermore, the process of spin-coating the organic polymer was tested. For the spin-coating process, different organic solvents were tested to ensure no negative reactions occurred with the magnetic injection electrodes. As a result of these tests, 1,2- dichlorobenzene was selected as the solvent for poly(3-hexylthiophene). The spin-coating process was calibrated, resulting in a range of available thicknesses of approximately 10-40 nm, selectable by adjusting the spin-coating rotational speed. To achieve high-quality magnetic electrodes, Ti35 image reversal photoresist was used to obtain a pronounced undercut. The specific recipe for applying this photoresist was tested, and the resulting photoresist profiles were imaged using scanning electron microscopy. These measurements show that a good undercut is achieved. Both back-gated and top-gated O-FET devices have been fabricated, and preliminary electrical measurements were performed on these devices. Difficulties with etching of the magnetic electrodes were traced to the organic solvent used for lift-off, and were solved by changing the organic solvent to a more suitable one. A combination of AFM and dark field microscopy images indicate that this mostly prevents the etching of magnetic electrodes. AFM measurements also indicate that lift-off is achieved without ridges on the edge of the electrodes, although some surface roughness is still observed in between the electrodes. In this work, major progress is reported on the fabrication recipe for magnetic O-FET devices. The optimisation of a method to obtain high-quality magnetic electrodes is a crucial step, since any imperfections in these electrodes will negatively influence the spin polarisation of the injected current. However, the fabrication recipe is not yet completely tested and optimised. Furthermore, no spin accumulation measurements have yet been done. In addition to many small improvements, three critical steps remain to be optimised in the fabrication recipe. The first step is finding a solution for the etching that is observed on the magnetic electrodes. Although the major etching problem is solved, minor etching pits are still visible. The second step is the organic etching step, using reactive ion beam etching. The third step is the integration of electron-beam lithography into the recipe, since it is suspected that a four-terminal device may be necessary for spin accumulation measurements. In such a device, two of the four terminals need to be closer together than is achievable using photolithography.

Abstract: PROBLEM TO BE SOLVED: To provide a half-split thrust bearing and a method of manufacturing the same, capable of effectively preventing fatigue separation and seizure of a lining layer even when local contact exists.SOLUTION: Undercut 15 is generated on a semicircular material 14 by punching out a bearing material 11 of a half-split bearing by pressing, thus a circular arc-shaped portion 13' continuously covering a surface 12A and a side face 12B of a back metal 12, is disposed on a radial edge portion of at least an inner peripheral side of a lining layer 13. Simultaneously, a thin portion 17 thinner than a thickness of a radial central portion of the back metal, is formed on the back metal, and a thickness of the thin portion 17 of the lining layer is thicker than a thickness of the radial central part.

Abstract: This paper reports the findings from a benchmark study testing several numerical methods, with a focus on the influence of undercut depth on block caving-induced surface deformation. A comparison is drawn between continuum v. discontinuum treatments of the modelled geology. Results were evaluated with respect to different simulated levels of ground disturbance, from complete collapse to small-strain subsidence. The results show that for a given extraction volume, the extent of ground collapse at surface decreases as undercut depth increases. The presence of sub-vertical faults was seen to limit the extent of the modelled caving zones. In contrast, the extent of small-strain surface subsidence was seen to increase with increasing undercut depth. The faults in this case did not have the same limiting effect. Overall, the findings emphasise the importance of balancing model simplification against the need to incorporate more complex and computationally demanding representations of the rock mass struc...

Abstract: The utility model discloses a rear undercut anchor. The rear undercut anchor comprises an anchor rod with an inverted cone head at one end, a nut matched with the other end of the anchor rod and an expansion sleeve which sleeves the anchor rod, wherein an expansion portion formed by a plurality of expansion pieces is arranged at one end of the expansion sleeve, close to the inverted cone head, an oblique plane is formed on the outer side of each expansion piece, the thickness of the free end of each expansion piece is less than the thickness of the bottom of each expansion piece, an undercut tool is arranged at the free end of each expansion piece, and corrosion protection coatings are respectively arranged on the outer sides of the anchor rod and the expansion sleeve. Compared with the prior art, the rear undercut anchor has the advantages that firstly, the undercut tools are arranged at the free ends of the expansion pieces, and therefore connection strength of the expansion sleeve and a hole wall is improved; secondly, the outer sides of the expansion pieces are set in oblique plane shapes, and then the undercut tools can deep penetrate into the hole wall under the circumstance that the external diameters of the undercut tools are respectively equal to the outer diameter of the expansion sleeve, and therefore the connection strength of the expansion sleeve and the hole wall is improved, and simultaneously the external diameters of the undercut tools are respectively equal to the outer diameter of the expansion sleeve.

Abstract: PROBLEM TO BE SOLVED: To provide a tandem gas shield arc welding method for deeply penetrable horizontal fillet welding, by providing an excellent bead shape in low sputter, without causing an undercut, by using 100% carbon dioxide for any of a preceding electrode and a succeeding electrode these, by setting both of them in reverse polarity.SOLUTION: A torch angle θof a preceding electrode 4 composed of a solid wire and a torch angle θof a succeeding electrode 5 composed of a flux-cored wire, are respectively set so as to become "5°≤θ<40°" and "40°≤θ≤60°", and a 100% carbon dioxide is used as a shield gas G of both electrodes. At this time, a welding voltage Vbeing a welding parameter of the preceding electrode 4 is 26-38 [V], and a welding current Iis 350-550 [A], and the welding voltage V[V]and the welding current I[A] satisfy a relationship of "56≤(V.10/I)≤84".

Abstract: The present invention relates to an undercut extractions apparatus for an injection mold. The undercut extracting apparatus is formed between a bottom plate and a fixation plate and comprises: the bottom plate which includes a molding hole formed so that one side is opened, an accommodation hole formed to be connected to the lower part of the molding hole and a sliding part containing a pin guide hole; a push plate which includes an eject pin fixed and installed in order to extract an injection product by elevation operation; a guide axis which supports the operation of the push plate by being formed at both side of the push plate; and a molding core which includes a driving shaft performing reciprocal movement according to the elevation operation of the push plate, a molding unit combined to the upper part of the driving shaft and a driving force providing means providing elastic force in order to operate the driving shaft by being combined to the lower end of the driving shaft.

Abstract: The invention relates to a formation method of a semiconductor packaging structure. The formation method comprises the steps of providing a semiconductor substrate, wherein a welding pad layer is formed on the semiconductor substrate; forming a passivation layer which covers the surfaces of the semiconductor substrate and the welding pad layer, wherein a first opening for exposing the surface of the welding pad layer is formed in the passivation layer; forming an under-bump metal layer at the first opening; forming a metal post on the under-bump metal layer; etching to remove the under-bump metal layer on the two sides of the metal post, wherein the edge of the remaining under-bump metal layer at the bottom of the metal post has an undercut defect which is depressed towards the bottom of the metal post; forming a sacrificial layer, wherein the sacrificial layer fills the undercut defect; forming a second mask layer which covers the sacrificial layer, the passivation layer and the metal post, wherein a third opening for exposing the surface of one end of the sacrificial layer is formed in the second mask layer; removing the sacrificial layer along the third opening to form a cavity, wherein the cavity is communicated with the third opening; forming a compensation layer for filling the undercut defect, wherein the compensation layer is made of a metal material. The formation method provided by the invention has the advantage that the reliability and the stability of the packaging structure are improved.

Abstract: PROBLEM TO BE SOLVED: To provide an undercut treatment mechanism capable of coping with requirement of save spacing by forming into a compact size, capable of being constituted simply without labor and time for assembly, capable of achieving cost down, especially capable of die cutting a formed product having an undercut part over its whole circumferential direction on an outer circumferential side surrounding an inner hole of the formed product easilySOLUTION: A pair of undercut forming cores 30A, 30B surrounding a core 50 from a whole circumferential direction are stored in a holder 40 provided in a movable mold 13 The forming cores 30A, 30B are movable to a forming position coming into contact each other while surrounding the core 50 and to a separation position separating each other, and are guided into escape directions having a same or different angle with respect to the horizon, respectively