Robert Boschgmbh

Guenther Findler

Jiri Marek

Michael Offenberg

Horst Muenzel

Juergen Buchholz

Udo Jauernig

Uwe Konzelmann

Helmut Baumann

Hans-Peter Trah

Botho Ziegenbein

Josef Kleinhans

Frank Bantien

Eckart Reihlen

Martin Willmann

Joerg Muchow

Uwe Lipphardt

Alexandra Boehringer

Nils Kummer

Richard Bischof

A semiconductor chip, which is preferably designed as a pressure sensor, has on its rear side one or more depressions in which the pressure is measured by correspondingly designed diaphragms which are coupled to piezosensitive circuits. The surface of the depressions and, optionally, the rear side of the semiconductor chip are coated with a protective layer which ensures that the semiconductor is protected from aggressive media. The protective layer thereby makes it possible to use the sensor universally in acids, lyes or hot gases.

Semiconductor sensor having a protective layer

A silicon orifice element includes an upper silicon plate and a lower silicon plate. A liquid can be injected through injection orifices of the upper silicon plate. Recesses which form air conduits are present in the lower silicon plate. The atomization and spray angle of the liquid stream passing through the injection orifices can be influenced by certain arrangements of the air conduits.

Orifice element

Orifice elements for use in valves for injecting fuel or a fuel-gas mixture. The orifice elements include two silicon plates, joined to one another. An upper plate has one or more injection orifices. The lower plate has a through hole introduced in it, through which a fuel jet can emerge. The lower plate follows in the downstream direction and includes a jet splitter. The jet splitter divides the through hole into at least two passthrough openings so that a dual-jet characteristic is produced or maintained for the valve. At least two conduits are formed between the upper plate and the lower plate. Gas is provided via the conduits and is mixed with the fuel discharged through the injection orifice. The injection orifice and the valve are particularly suited for injection systems of mixture-compressing internal-combustion engines having externally supplied ignition.

Orifice element and valve with orifice element

A mass flow sensor includes a measuring element arranged on a membrane that is clamped in a frame. The sensor is formed by introducing a recess into a silicon wafer. Through the application of a recess having perpendicular walls, the thickness of the frame can be reduced, thus allowing the required surface area of the wafer to also be reduced.

Mass flow sensor having a measuring element arranged on a membrane

A mass-flow sensor includes a measuring element on a membrane and a media-temperature measuring element on a separate membrane. By configuring the media-temperature measuring element on a membrane, the mass-flow sensor quickly reacts to changes in the temperature of the flowing medium.

Mass-flow sensor

A capacitive sensor has a plurality of mutually insulated metallized silicon wafers or plates, the bond bases of which were treated by etching to create trapezoidally-cross-sectional bonding bases or pads for wire-bonding of the individual silicon plates. The stray capacitance caused by the bond bases is reduced by this step and the value of the stray capacitance becomes exactly reproducible.

Capacitive sensor

A method for fabricating silicon injection plates is both highly precise and particularly simple. The silicon injection plate is formed by an upper silicon plate having injection holes and a lower silicon plate having a through opening and channels. The lower silicon plate is fabricated by simultaneous, double-sided etching of silicon.

Method for the manufacture of silicon injection plates and silicon

A method for producing capacitive sensors which is used in particular for the parallel production of capacitive sensors with exactly defined stray capacitance. For this purpose, troughs (15, 16, 17) are cut along or parallel to the splitting lines (6), so that adjustment errors in the position of the cut, during separation of the sensors, and variations in the cut width have no effect on the stray capacitance.

Method of making sensor

Device for one-sided etching of a semiconductor wafer

A method for anisotropically etching recesses in a monocrystalline disk-shaped wafer is proposed, by which structural elements such as membranes or through openings can be made in the wafer. To this end, a mask layer is applied to a first surface of the wafer and subsequently structured by making at least one opening in the mask layer. The dimensioning of the at least one opening, and its orientation with respect to the crystal orientation of the wafer and to the anisotropic properties of the wafer material, are selected such that the desired size and shape of the area of the recess or outlet hole are attained by anisotropic etching into the wafer through the at least one opening in the mask layer and by purposeful underetching of the mask layer.

Method of anisotropically etching monocrystalline, disk-shaped wafers

Processes are proposed for structuring monocrystalline semiconductor substrates provided with a basic doping, in particular silicon substrates with a (100) or (110) crystal orientation. In this process, at least one main surface of the semiconductor substrate is passivated by means of a structured masking layer, and in an etching step etching into the semiconductor substrate is done anisotropically through openings in the masking layer. It is proposed that as the masking layer (12), a structured, preferably monocrystalline, layer of the basic material of the semiconductor substrate be used, which is doped such that a pn junction is produced between the masking layer (12) and the semiconductor substrate (10), the junction being polarized in the depletion direction and serving as an etch stop. It is also proposed that the semiconductor substrate (10) be formed of a substrate (11) and at least one layer (13), applied thereon, with buried zones (16), with pn junctions being produced between the zones (16) and the substrate (11). Zones (16) that are electrically insulated from one another and the semiconductor substrate (10) are electrically bonded, so that the pn junctions are polarized in the depletion direction and serve as an etch stop for deep etching.

Method of structuring a semiconductor chip

Electrochemical etching of silicon wafers or plates, on the front side of which a monocrystalline epitaxy layer is provided having a doping of a type opposite to the doping of the remainder of the silicon plate, so as to provide a pn or np junction, is performed with an organic photo film material of negative type and polyisoprene base serving as a passivating layer on the previously etched and metallized front (epitaxy) side. The film layer is held in place with the help of an adhesion promoting silane compound and covers the entire front side including the portions previously masked with silicon nitride or oxide. It is dried and hardened before exposure to the etchant which is used to etch the rear side of the plate until the etchant reaches the pn junction, where a small voltage bias applied to the junction from the front side assures an etch-stop. Etchants containing tetraalkylammonium hydroxide in water solution or in water-free form are preferred, with various additives as inhibitors, complexing agents and/or wetting agents.

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Stuttgart, Germany

Guenther Findler