Abstract: A gettering unit encompasses a silicon substrate, a thin film heater disposed on the silicon substrate, and a gettering layer disposed selectively on the thin film heater. Here, the thin film heater is made of metallic film such as platinum (Pt) or chromium (Cr) film. The area of the gettering layer is smaller than the area for the thin film heater so as to expose first and second end terminals of the thin film heater. The first and second end terminals of the thin film heater serves as the bonding pads in the assembling process.

Abstract: An etching process for a silicon semiconductor substrate to produce a semiconductor pressure sensor or a semiconductor acceleration sensor. The etching process comprises the following steps: (a) carrying out an etching of the semiconductor without application of a voltage to the semiconductor so as to accomplish a pre-etching step, the pre-etching step including dipping the semiconductor in hydrazine hydrate; and (b) carrying out an electrochemical etching of the semiconductor by applying pre-etching step so as to accomplish a final etching step, the final etching step including dipping the semiconductor in an alkali system etching solution containing at least hydrazine (N.sub.2 H.sub.4), potassium hydroxide (KOH), and water (H.sub.2 O), the alkali system etching solution containing potassium hydroxide in an amount of not less than 0.3% by weight.

Abstract: A method of producing a device having a minute structure such as a semiconductor element. The producing method comprises the following steps: (a) forming a film of liquid containing a sublimable material on a surface of a product of the device, the sublimable material being solid ordinary temperature and at normal pressure, the minute structure being formed at the surface of the product; (b) improving a wettability of at least one of the minute structure and a region surrounding the minute structure by the liquid film of the sublimable material; (c) converting the liquid film into a state containing the sublimable material in solid phase so as to form a protective film; and (d) vaporizing the protective film to be removed.

Abstract: An electrochemical etching process carried out in an etching system including an electrolysis vessel which is provided thereinside with facing wall surfaces defining therebetween an etching solution flow region. A semiconductor substrate to be etched and a counter electrode are mounted respectively on the facing wall surfaces. A flow stream generating section for the etching solution is formed separate from the etching solution flow region and includes a device for generating the flow stream of the etching solution. The flow stream generating section is connected to the etching solution flow region in such a manner that the etching solution flow in a direction generally parallel with the facing wall surfaces inside the electrolysis vessel. An electric potential is applied between the semiconductor substrate and the counter electrode to accomplish an electrochemical etching on the semiconductor substrate.

Abstract: A semiconductor device is produced through electrolytic etching process. The device comprises a P-type silicon substrate. An N-type epitaxial layer is formed on the silicon substrate. P-type regions are defined in the N-type epitaxial layer. N-type regions are defined in some of the P-type regions. A first wiring layer connects to predetermined ones of the P-type regions. A second wiring layer connects to predetermined ones of the N-type regions. The semiconductor device has a given part which has such a possibility that a predetermined magnitude of leakage current flows therethrough between the first and second wiring layers when subjected to the electrolytic etching process. The semiconductor device further has a circuit which is electrically connected to one of the first and second wiring layers. The circuit is capable of removing the possibility of the leakage current flow through the given part when opened.

Abstract: An etching device performing an etching process on a material immersed in a etchant which is a mixture of acids of which the main components are fluoric acid, nitric acid, and acetic acid. The etching device includes a semiconductor electrode immersed in the etchant, an opposing electrode immersed in the etchant, an electron meter for detecting an electric potential difference between the semiconductor electrode and the opposing electrode, and a controller for uniformly controlling the nitrite ion concentration in the etchant from the electric potential difference between the semiconductor electrode and the opposing electrode, detected by the electronmeter.

Abstract: Disclosed is a method of etching comprising preparing an etching solution containing hydrofluoric acid and nitric acid, and etching while adding nitrite ion or a medium for producing nitrite acid ion to the etching solution. As the medium for producing the nitrite ion, silicon with a high impurity concentration, a mixed acid solution containing hydrofluoric acid and nitric acid having been used for dissolving a great amount of silicon, or gaseous nitrogen dioxide may be used. Preferably, the concentration of nitrite ion in the etching solution is detected based on the concentration of NO.sub.x in the gas phase which is in an equilibrium relation to the nitrite ion in the liquid phase of the etching solution, and necessary nitrite ion are added to the etching solution based on the concentration of NO.sub.x.

Abstract: To eliminate the influence of fluctuations in etching liquid sorts, composition, density, degradation, temperature, agitation etc., a method of selectively etching a semiconductor substrate having an n-type layer and a p-type layer and immersed in an electrolytic solution comprises the steps of: applying an etching voltage to the n-type layer; integrating etching current flowing through the substrate; if the integrated current value exceeds a reference value required to etch the p-type layer to a predetermined depth, increasing the etching voltage; if the potential of the substrate relative to a reference electrode reaches a predetermined value at which only the p-type layer can be etched, keeping the increased etching voltage at the current level to further etch only the p-type layer; and if the etching current drops sharply due to formation of an anodic oxidation film on the n-type layer, completing the substrate etching.

Abstract: A semiconductor wafer including a plurality of chips having respective portions to be etched electrochemically with application of an electric voltage to the semiconductor wafer immersed in an etching solution. The semiconductor wafer includes electric circuits formed therein for controlling electric energy applied to the respective portions.

Abstract: An electrochemical etching method for producing semiconductor diaphragms from a semiconductor wafer comprised of a first semiconductor layer of a first conductivity type and a second semiconductor layer formed on the first semiconductor layer, the second semiconductor layer having a second conductivity type different than the first semiconductor layer. The semiconductor wafer is placed in an etching solution with respect to a counter-electrode immersed in the etching solution. The semiconductor wafer has a plurality of chips each of which includes at least one third semiconductor layer of the first conductivity type. The third semiconductor layer extends through the second semiconductor layer to the first semiconductor layer. A first positive potential is applied to the first and third semiconductor layers with respect to the counter-electrode. A second positive potential is applied to the second semiconductor layer with respect to the first semiconductor layer.

Abstract: Two semiconductor substrates, each having a polished surface and at least one groove is formed in the surface of at least one of the two substrates, are tightly and inseparably joined by the steps of wetting the polished surface of at least one of the two substrates with a liquid not containing any solute that causes precipitation of a solid substance upon evaporation of the liquid, e.g. methanol or water, placing one substrate on the other so as to bring the polished surfaces of the two substrates into contact with each other with intervention of a thin film of the liquid therebetween and, after a while, subjecting the provisionally joined substrates to a heat treatment and then forming a dielectric layer of organic polymer or silicon compound in at least one groove. This method is suitable for joining silicon substrates such as silicon wafers now on the market.