Abstract: The side edge of the main magnetic pole layer is prevented from protruding in the track width direction even when a skew angle is generated by forming the main magnetic pole layer of the opposing face opposing the recording medium as an inverted trapezoid, thereby enabling the occurrence of side fringing to be prevented.

Abstract: A method for fabricating a multi-level micro-fluidic device for an micro-fluidic injection head equipped with symmetrical heaters. The method incorporates two thick photoresist deposition processes, a light-absorbing layer deposited in-between and a nickel-containing material electroplating process. The first thick photoresist deposition process is carried out to form a primary ink chamber in fluid communication with a funnel-shaped manifold and an injector orifice. The light-absorbing layer is deposited to prevent overheating of the first photoresist layer during a subsequent metal seed layer sputtering process. The second thick photoresist deposition process forms a mold for forming an injector passageway that leads to the injector orifice. The nickel-containing material electroplating process provides an orifice plate on top of the injection head through which an injector passageway that leads to the injector orifice is provided for injecting ink droplets.

Abstract: The magnetic head of the present invention, includes a second magnetic pole (P2 pole) that is fabricated upon a write gap layer that is deposited upon a flat surface. To achieve the flat surface, a P1 pole pedestal is formed upon the P1 pole layer with a sufficient thickness that the induction coil structure can be fabricated beneath the write gap layer. In the preferred embodiment, an etch stop layer is formed upon the P1 pole layer and an ion etching process is utilized to form the induction coil trenches in an etchable material that is deposited upon the etch stop layer. Following the fabrication of the induction coil structure a CMP process is conducted to obtain a polished flat surface upon which to deposit the write gap layer, and the P2 pole is then fabricated upon the flat write gap layer. The magnetic head of the present invention can be reliably fabricated with a more narrow P2 pole tip base width, such that data tracks written by the magnetic head are likewise narrower.

Abstract: An electrode film and a protective electrode film are formed on an insulating film and a first magnetic film in turn. Then, a first photoresist layer, an intermediate layer and a second photoresist layer are formed on the protective electrode film in turn. The intermediate layer is formed by a sputtering method so that the surface temperature of the intermediate layer is set to 140° C. or below. Then, the first photoresist layer is exposed and developed, to fabricate a photoresist pattern. Then, the intermediate layer is partially etched and removed via the photoresist pattern as a mask by a reactive ion etching method using a chlorine-based gas.

Abstract: A recording/reproduction element is mounted on a magnetic head slider via a piezoelectric element so that a displacement of the piezoelectric element performs fine control of the position of the recording/reproduction, thus enabling fine spacing and high track positioning accuracy. This improves linear recording density and track density. A pair of electrodes are formed on both sides of a piezoelectric element to constitute a piezoelectric actuator. One electrode is arranged opposite the rear surface (air flow out end) of a magnetic head slider 11. A recording/reproduction element is arranged on and electrically insulated from the other electrode. The piezoelectric element includes a piezoelectric element displaced in a spacing direction, enabling fine spacing control, a piezoelectric element displaced in the track direction, enabling a fine track position control, and a piezoelectric element displaced in a magnetic disc rotation direction, enabling reduction of jitter of a reproduction signal.

Abstract: A method for manufacturing a structure, including the steps of forming on the substrate a piling of a first insulating layer, a first metallization level, a second insulating layer, and a second metallization level, opening in the second metallization level and in the second insulating layer first windows corresponding to the contour of the first openings and second windows, the external contour of which corresponds to the internal contour of the second openings, forming in a masking layer third windows larger than the first windows, etching the first metallization level in the first windows, removing the second metallization level under the masking layer to as far as the internal periphery of the second windows, etching by a chosen distance the first insulating layer, and simultaneously removing the second insulating layer within the contour of the second windows, and removing the masking layer.

Abstract: A method of depositing a film on a substrate disposed in a substrate processing chamber. The method includes depositing a first portion of the film by forming a high density plasma from a first gaseous mixture flown into the process chamber. The deposition processes is then stopped and part of the deposited first portion of the film is etched by flowing a halogen etchant into the processing chamber. Next, the surface of the etched film is passivated by flowing a passivation gas into the processing chamber, and then a second portion of the film is deposited over the first portion by forming a high density plasma from a second gaseous mixture flown into the process chamber. In one embodiment the passivation gas consists of an oxygen source with our without an inert gas.

Abstract: A Damascene process is provided for manufacturing a coil structure for a magnetic head. During the manufacturing process, an insulating layer is initially deposited after which a photoresist layer is deposited. A silicon dielectric layer is then deposited on the photoresist layer. After masking the silicon dielectric layer, at least one channel is etched in the photoresist layer and the silicon dielectric layer. Then, a conductive seed layer is deposited in the at least one channel. The at least one channel is then ready to be filled with a conductive material and chemically/mechanically polished to define a coil structure.

Abstract: Circuit boards (1100, 1400) and methods for fabricating circuit boards that include conduits (1004) are provided. The conduits formed by patterning a metal layer (1102) are lined by inert coating (1106) and caped by a photodefinable polymer layer (1110) that is affixed to the inert coating by with the help of an initially uncured polymer layer (1106). Holes are formed by patterning the photodefinable polymer layer for admitting and removing fluid from the conduit.

Abstract: A TMR element includes: a free layer formed on a lower gap layer; a tunnel barrier layer formed on the free layer; and a pinned layer formed on the tunnel barrier layer. The pinned layer and the tunnel barrier layer have sidewalls formed through etching. The TMR element further comprises a deposition layer made of a material that is separated by etching and deposits on the sidewalls and undergoes oxidation.

Abstract: A method for reducing feature size in a thin film magnetic write head includes plating a seed layer over a selected base layer, spinning a photoresist layer onto the seed layer, defining a trench in the photoresist layer, depositing an insulative spacer layer to cover the trench side walls using a low temperature chemical vapor deposition process, anisotropically etching to remove spacer layer material from the bottom of the trench and thereby expose the plating seed layer while leaving intact vertical portions of the spacer layer that cover the trench side walls and narrow its width, forming a structure of reduced feature size by electroplating metallic material into the narrowed trench, stripping away the photoresist layer and the spacer layer vertical portions, and milling or sputter etching the plating seed layer to leave a structure of reduced feature size.

Abstract: A magnetic disk apparatus includes a magnetic reproducing head portion, and a magnetic recording head including a lower magnetic core and an upper magnetic core having a end portion and a rear portion. The rear portion is formed using a negative resist or an electron beam resist to form a frame for plating above the end portion of the upper magnetic core head.

Abstract: An integrated lead suspension includes a solder ball that is placed between a lead wiring pad provided on a flexure of the suspension, and a bonding pad provided on a slider of a head gimbal section. The lead wiring pad and bonding pad are soldered by melting the solder ball. As a result, there is provided a recessed section into which a solder ball is placed by way of surface raised sections, using gravitational force, in the vicinity of the center line of the surface of the lead wiring pad. In this way the position of the solder ball is not displaced from the center line when a bonding pad and lead wiring pad are connected by means of a solder ball.

Abstract: A method for producing transducers having a 1-3 composite structure. The transducer element includes a plurality of thin piezoceramic wafers which are electroded on opposing major surfaces. The spaced wafers are separated by a passive polymer layer in a composite structure and the electrodes on the opposing major surfaces are connected to different ones of top and bottom electrode surfaces.

Abstract: The invention provides microfabricated silicon substrates and devices having extremely small apertures (termed “nanoapertures”) and methods for producing such nanoapertures. The devices have a nanoaperture (which may have a diameter ranging from about a few millimeters to as small as a few nm) across a substrate effective to connect two regions separated by the substrate. The devices are suitable for the formation of lipid bilayer membranes across the apertures, and for use in devices such as biosensors. Substrates and devices may include multiple nanoapertures, which may each support a lipid bilayer membrane, allowing fault tolerant devices such as fault-tolerant biosensors, and allowing devices able to sense more than one target molecule.

Abstract: A method of making a magnetic head assembly wherein the magnetic head assembly has a write head with a pole tip includes the steps of forming a shaping layer on an underlying layer wherein the shaping layer has a side surface and a top surface, ion beam sputter depositing a ferromagnetic material layer on the underlying layer and on the side and top surfaces of the shaping layer and removing first and second portions of the ferromagnetic material layer from the underlying layer and the top surface of the shaping layer, respectively, leaving a remaining portion of the ferromagnetic material layer on the side surface of the shaping layer which is the aforementioned pole tip.

Abstract: Polysilicon formed over an underlying insulator may be highly selectively etched. Therefore, polysilicon may be selectively etched using tetraalkylammonium hydroxide or NH4OH to define a nitride waveguide. The resulting nitride waveguide may have smoother surfaces resulting in less loss of light intensity as light travels through the nitride waveguide.

Abstract: A method of micro-machining comprising providing a primary region of at least a first material which contacts a second material at at least one end portion thereof, the method comprising providing an infill material on to the second material, patterning and etching said infill material to form a hole through the infill material to the second material, depositing the first material on to said infill material so that the at least one portion of the first material contacts the second material through the hole. The method can be used to provide a track bridging suspended portions of micro-machined structures. Also a method of narrowing and sealing top portions of channels cut into a wafer is disclosed.

Abstract: In order to clean a semiconductor device having a dielectric layer deposited on a top surface of a lower metal wiring of the semiconductor device, and a contact hole or a via hole formed in the dielectric layer to expose the lower metal line therethrough, the semiconductor device is located within a radio frequency (RF) cleaning chamber. A gas mixture of HCl and H2O is introduced into the RF cleaning chamber and Ar gas plasma is generated in the RF cleaning chamber to excite HCl gas so that the HCl gas and an excited HCl gas are used to remove carbon radicals and metal particles.

Abstract: The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon micro-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

Abstract: A method of manufacturing a thin film magnetic head in which a top pole is divided into a pole tip and a tope pole layer, and the pole tip is formed on the flat surface of a bottom pole with a write gap layer in between. An insulating layer is formed in a region adjacent to the pole tip. A first layer of thin film coil is formed in a region wherein the insulating layer is formed. The thin film coil is covered by the insulating layer whose surface is flattened. A surface of the top pole layer facing the recording medium can be formed recessed from a surface of the pole tip facing the recording medium.

Abstract: The present disclosure pertains to our discovery of a method of etching a shaped cavity in a substrate, where the shaped cavity has a width that is at least as great as its depth. We have discovered that by varying the process chamber pressure during etching of the shaped cavity, we can control lateral etching of the shaped cavity, while allowing the removal of etch process byproducts from the shaped cavity during continued etching. The method of the invention can be used to etch shaped cavities having round or horizontal elliptical shapes. The method of the invention is particularly useful in the etching of buried cavities, where removal of etch byproducts from the cavity can be difficult.

Abstract: A liquid resist is introduced between adjacent conductive lines of a coil pattern girdling around a magnetic core piece. When the liquid resist is cured, an insulating resin filler can be fixed between the adjacent conductive lines of the coil pattern. An insulating metallic layer is formed to extend over the insulting resin filler and the conductive lines of the coil pattern. Thereafter, the insulating metallic layer is subjected to a flattening grinding treatment until at least a part of the conductive line is exposed at a flattened surface. Of the resist, of a higher fluidity, penetrates in every hole and corner between the adjacent conductive lines, the gap defined between the adjacent conductive lines is fully filled with the insulating material. No voids remain in the gap. The conductive line of the coil can be reliably prevented from corrosion or oxidation. Moreover, a relatively brittle of fragile insulating resin filler is reliably prevented from being subjected to the flattening.

Abstract: A method for manufacturing a micromechanical part, having a plurality of components that move with respect to one another, from a substrate, with a conductive coating being applied to at least one facing surface of the plurality of components that move with respect to one another.

Abstract: A working method of a bar block with a plurality of magnetic head elements and a plurality of pairs of electrode terminals electrically connected to the plurality of magnetic head elements arranged on an element-formed surface of the bar block in at least one line. This method includes a step of pre-laminating an ACF on the element-formed surface of the bar block, a step of bonding a conductive plate member with a plurality of projections located at positions faced to the plurality of pairs of terminal electrodes of the bar block, respectively, on the ACF so that each pair of the terminal electrodes is electrically short-circuited with each other, and a step of, then, working the bar block.

Abstract: A method of forming a device, comprising the following steps. A wafer holder and inner walls of a chamber are coated with a seasoning layer The wafer is placed upon the wafer holder and is cleaned wherein a portion of the seasoning layer is re-deposited upon the wafer over and between adjacent wafer conductive structures. The wafer is removed from the chamber and at least two adjacent upper metal structures are formed over at least one portion of a metal barrier layer. The exposed portions of the metal barrier layer are etched and removed, exposing portions of the re-deposited seasoning layer portions using the metal barrier layer etch process which also removes any exposed portions of the re-deposited seasoning layer portions that are comprised of a material etchable in the metal barrier layer etch process.

Abstract: The present invention is directed to methods for editing copper features embedded within an organic body by exposing at least a portion of a top surface of the copper feature, forming a mill box there-over and then simultaneously milling both the copper feature and any organic material exposed through the mill box in a single step using an ion beam in combination with a XeF2 gas for a dwell time of at least 10 milliseconds. The invention dramatically increases the efficiency of Focused Ion Beam milling of copper features embedded in organic layers by milling these features in a gas-depleted environment at significantly increased dwell time while avoiding the problems of graphitization, destruction of the organic layer and metal redeposition.

Abstract: A method of making a small-diameter through hole having high reliability with regard to a hole wall at a high rate with the energy of a high-output carbon dioxide gas laser without pre-making any hole in a copper foil, forming or disposing a coating or a sheet of an organic substance containing 3 to 97% by volume of at least one powder selected from the group consisting of a metal compound powder, a carbon powder and metal powder which have a melting point of at least 900° C.

Abstract: A method of making an interposer having an array of contact structures for making temporary electrical contact with the leads of a chip package. The contact structures may make contact with the leads substantially as close as desired to the body of the chip package. Moreover, the contact structures can be adapted for making contact with leads having a very fine pitch. In a first embodiment, the contact structures include raised members formed over a body of the interposer. A conductive layer is formed over each of the raised members to provide a contact surface for engaging the leads of the chip package. In another embodiment, the raised members are replaced with depressions formed into the interposer. A conductive layer is formed on an inside surface of each depression to provide a contact surface for engaging the leads of the chip package. Moreover, any combination of raised members and depressions may be used.

Abstract: A process of removing excess holefill material from a surface of an electronic substrate in which the holefill residue is contacted with a swelling agent followed by planarizing of the surface in the presence of an agent no stronger than a liquid having a pH of about 6 to about 8.

Abstract: A method is provided for forming sub-micron-size structures over a substrate. A width-defining step is formed over the substrate. A width-defining layer is formed over an edge of the width-defining step. The width-defining layer is etched back to leave a spacer adjacent the width-defining step. A length-defining step is formed over the substrate. A length-defining layer is formed over an edge of the length-defining step. The length-defining layer is etched back to leave a spacer adjacent a first edge of the length-defining step and across a first portion of the spacer left by the width-defining layer. The length-defining step is then removed. The spacer left by the width-defining layer is then etched with the spacer left by the length-defining layer serving as a mask, to form the structure.

Abstract: A circuit board comprising a resin molded article which includes a metal powder coated by an insulation film and a metal conductor which is formed by metal deposition over a circuit pattern drawn by laser beam irradiation on the surface of the resin molded article through electroless plating, and the method of producing the same.

Abstract: In one embodiment, a fluid ejection device comprises a substrate having a fluid slot defined from a first surface through to a second opposite surface; an ejection element formed over the first surface and that ejects fluid therefrom; and a filter having feed holes positioned over the fluid slot near the first surface. Fluid moves from the second surface through the feed holes to the ejection element. In a particular embodiment, the filter is formed of a first material that is surrounded by a second material. In another particular embodiment, the filter is formed from the back side and is formed of the same material as the substrate.

Abstract: A process of forming a two-piece pole for an inductive write head involves first forming a first pole piece having a width between opposite side surfaces defining a gap width of a transducing gap at an air bearing surface of the head. The process next involves forming a second pole piece having a first region remote from the air bearing surface and a second region extending from the first region toward the air bearing surface. The first region is wider than the width of the first pole piece. The second pole piece is formed so that at least a portion of the second region is contiguous a portion of the first pole piece and so that no sharp external corners exist between the first pole tip piece and the second pole piece within a pole tip region of the head.

Abstract: A method of manufacturing a combination type thin film magnetic head having an inductive type thin film magnetic head supported by a substrate including forming a first magnetic layer extending from an air bearing surface and forming an insulating layer on a surface of a portion of the first magnetic layer such that the insulating layer extends at least the air bearing surface and includes a -shaped cut-out portion.

Abstract: A micromachined vertical vibrating gyroscope consists of three single crystal silicon assemblies: an outer single crystal silicon assembly, an intermediate single crystal silicon assembly, and an inner single crystal silicon assembly. The outer assembly includes a plurality of arc-shaped anchors arranged in a circle and extending from a single crystal silicon substrate coated with an insulating annulus thereon. The intermediate assembly is a suspended wheel concentric with the arc-shaped anchors. The inner assembly is a suspended hub concentric with the circle formed by the anchors and having no axle at its center. The three assemblies are connected to each other through several flexures. The intermediate suspended wheel is driven into rotational vibration by lateral comb capacitors. Input angular rates are measured by two vertical capacitors.

Abstract: Embodiments include a method for forming a head suspension assembly. A spacer layer is formed in or on a silicon wafer. A transfer film including an opening defining the shape of a slider support membrane is provided, and the opening is filled with a resin material. The transfer film with the resin material therein is positioned over the silicon wafer so that at least a portion of the resin material is positioned adjacent to the spacer layer. The resin material is baked to form a glassy carbon material. The spacer layer is etched to form a trench in the silicon wafer adjacent to the glassy carbon material, and a slider is positioned on the glassy carbon material over the trench.

Abstract: A method of reducing notching during reactive ion etching (RIE) is provided. The method is useful when RIE is performed to pass through a silicon layer on a multi-layered structure on which the silicon layer, an insulating layer and a silicon substrate are sequentially deposited. The method includes the steps of: forming an insulating layer on a silicon substrate; forming trenches on the insulating layer to expose the silicon substrate; forming a silicon layer on the insulating layer to fill the trenches; and patterning the silicon layer to form first etch regions, which pass through the silicon layer, to include the trenches. According to the method, it is possible to remarkably reduce notching without depositing a metal layer, when a multi-layered structure including a silicon layer which is etched to be passed through during RIE is fabricated.

Abstract: An exhaust gas sensor includes a housing and a sensor element supported by the housing. The sensor element includes a support member having an exhaust side, a reference side, and an aperture extending through the support member between the exhaust side and the reference side. The sensor element further includes an exhaust-side electrode on the exhaust side of the support member. The exhaust-side electrode is electrically connected to a contact on the reference side of the support member via a lead extending through the aperture. The aperture is sealed around the lead such that gas cannot pass through the aperture. The support member is oriented substantially parallel to the flow of exhaust gases when the exhaust gas sensor is installed on a vehicle. The sensor further includes a contact pin in the housing that engages the contact and biases the sensor element against a portion of the housing.

Abstract: A piezoelectric resonator is constructed to be vibrated in a square type vibration mode and to minimize the variations in the resonant frequency caused by the manufacturing process. The resonator includes a piezoelectric substrate having a pair of main surfaces, electrodes disposed on the pair of main surfaces and grooves provided on one of the main surfaces of the piezoelectric substrate. The grooves divide at least one of the electrodes into a plurality of divided electrodes. One of the plurality of divided electrodes defines an input/output electrode. A maximum distance between the outer edges of two of the grooves disposed opposite to each other across the input/output electrode is about 0.5 to about 0.55 times the length of one side edge of the piezoelectric substrate.

Abstract: A semiconductor processing component includes a quartz body characterized by silicon oxide filled micro cracks. The component is utilized as a processing component in a semiconductor furnace system. The quartz body is prepared by cleaning the component to remove a build up silicon layer and to expose micro cracks in the surface of the component and to etch the micro cracks into trenches. A silicon layer is applied onto the processing component body and at least a portion of the silicon is oxidized to silica to fill the trenches in the surface of the component body.

Abstract: A method of determining and correcting alignment during imprint lithography process is described. During an imprint lithographic process the template may be aligned with the substrate by the use of alignment marks disposed on both the template and substrate. The alignment may be determined and corrected for before the layer is processed.

Abstract: Three fundamental and three derived aspects of the present invention are disclosed. The three fundamental aspects each disclose a process sequence that may be integrated in a full process. The first aspect, designated as “latent masking”, defines a mask in a persistent material like silicon oxide that is held abeyant after definition while intervening processing operations are performed. The latent oxide pattern is then used to mask an etch. The second aspect, designated as “simultaneous multi-level etching (SMILE)”, provides a process sequence wherein a first pattern may be given an advanced start relative to a second pattern in etching into an underlying material, such that the first pattern may be etched deeper, shallower, or to the same depth as the second pattern. The third aspect, designated as “delayed LOCOS”, provides a means of defining a contact hole pattern at one stage of a process, then using the defined pattern at a later stage to open the contact holes.

Abstract: A micromachined fluid handling device having improved properties. The valve is made of reinforced parylene. A heater heats a fluid to expand the fluid. The heater is formed on unsupported silicon nitride to reduce the power. The device can be used to form a valve or a pump. Another embodiment forms a composite silicone/parylene membrane. Another feature uses a valve seat that has concentric grooves for better sealing operation.

Abstract: A process for fabricating micro-mirrors on a silicon substrate is disclosed, which can markedly improve the flatness of micro-mirrors, reduce the scattering of incident light, and increase S/N ratio. The fabrication process comprises the steps of: forming micro-planes along a certain direction on a silicon substrate to serve as mirrors; forming a SiO2 layer on the silicon substrate; and melting the SiO2 layer on the micro-planes by a heating process and then crystallizing SiO2 again to form micro-mirrors. Further, instead of coating the SiO2 layer, a metal layer can be used to form a eutectic structure with the silicon substrate. After the micro-mirrors are formed, a layer of Au can be coated thereon to increase the reflectance of the micro-mirrors.

Abstract: A process of forming a microactuator for positioning a transducing head over a selected radial track of a rotatable disc in a disc drive system is disclosed. A tub is etched in a substrate, and a bottom coil layer is plated at least partially in the tub. A first insulating layer is deposited on the bottom coil layer. A ferromagnetic core layer is formed on the first insulating layer. A second insulating layer is deposited on and around the ferromagnetic core layer. A top coil layer is plated on the second insulating layer, and contacts the bottom coil layer at a point spaced from the ferromagnetic core. A rotor is formed on a rotor substrate to confront the ferromagnetic core, is operatively attached to the slider and is movable with respect to the ferromagnetic core.

Abstract: In a mass flow sensor having a layered structure on the upper side of a silicon substrate (1), and having at least one heating element (8) patterned out of a conductive layer in the layered structure, thermal insulation between the heating element (8) and the silicon substrate (1) is achieved by way of a silicon dioxide block (5) which is produced beneath the heating element (8) either in the layered structure on the silicon substrate (1) or in the upper side of the silicon substrate (1). As a result, the sensor can be manufactured by surface micromechanics, i.e. without wafer back-side processes.

Abstract: Polysilicon formed over an underlying insulator may be highly selectively etched. Therefore, polysilicon may be selectively etched using tetraalkylammonium hydroxide or NH4OH to define a nitride waveguide. The resulting nitride waveguide may have smoother surfaces resulting in less loss of light intensity as light travels through the nitride waveguide.

Abstract: A cross-section is obtained in which a sample shape is clearly delineated by forming a covering layer of a material different from that of the sample surface on the sample surface, forming a protective layer on the covering layer forming a hole in the protective and covering layers and the sample surface to expose the cross-section, and tilting the sample and scanning the cross-section with a focused ion beam so as to obtain a microscopic image of the cross-section. By forming the covering layer of a material different from that of the sample surface, the shape of the sample can be clearly viewed in the obtained image.

Abstract: A method for making a thin-film magnetic head having a magnetoresistive effect element wherein an insulating layer is formed under an electrode layer of a magnetoresistive effect element with a lower gap layer interposed therebetween. As a result, the distance between the electrode layer and the lower shielding layer becomes longer, thus permitting maintenance of a satisfactory electrical insulation.