초록 ▼

The invention relates to a microstructure in a preferably electrically conductive substrate (1), more specifically made of doped single crystal silicon, with at least one functional unit (2.1, 2.2) and to a method of fabricating the same. In accordance with the invention, the functional unit (2.1, 2

The invention relates to a microstructure in a preferably electrically conductive substrate (1), more specifically made of doped single crystal silicon, with at least one functional unit (2.1, 2.2) and to a method of fabricating the same. In accordance with the invention, the functional unit (2.1, 2.2) is mechanically and electrically separated from the substrate (1) on all sides by means of isolation gaps (5, 5a) and is connected, on at least one site, to a first structure (4a) of an electrically conductive layer (S) that is electrically isolated from the substrate (1) by way of an isolation layer (3) and that secures the unit into position relative to the substrate (1). For this purpose, the functional unit (2.1, 2.2) is released from the substrate (1) in such a manner that the isolation gaps (5, 5a) are provided on all sides relative to the substrate (1). The electrically conductive layer (S) is applied in such a manner that it is connected through contact fingers (4a) for example to the functional unit (2.1, 2.2) which it secures into position. The method in accordance with the invention permits to substantially facilitate the manufacturing process and to produce a microstructure with but small parasitic capacitances.

대표청구항 ▼

1. A method of producing a microstructure comprising the steps of:(a) completely mechanically and electrically separating from a substrate on all sides by means of isolation gaps at least one functional unit comprising a fastening anchor, at least one spring part bordering on the fastening anchor, a

1. A method of producing a microstructure comprising the steps of:(a) completely mechanically and electrically separating from a substrate on all sides by means of isolation gaps at least one functional unit comprising a fastening anchor, at least one spring part bordering on the fastening anchor, and at least one mass part connected to the spring part; and(b) depositing an electrically conductive layer so as to connect the fastening anchor via a first structure comprising a plurality of contact fingers formed in the electrically conductive layer to the electrically conductive layer, the contact fingers overlapping the isolation gaps as a bridge to secure the fastening anchor into position.2. The method of claim 1, wherein the following method steps are performed:producing on the surface of the substrate an isolation layer with openings by patterning those regions which define the fastening anchor and the future surrounding first lateral isolation gaps between the substrate and the fastening anchor,depositing the electrically conductive layer onto the isolation layer and onto that region, which is not provided with an isolation layer and will form the fastening anchor and, concurrently or subsequently,patterning the electrically conductive layer in such a manner that at one site at least, a first structure of the electrically conductive layer remains connected to the fastening anchor to be produced, said connection extending through the future first lateral isolation gap between substrate and functional unit, and configuring a second structure of the electrically conductive layer that is connected to the first structure and, if necessary, a conductive pattern of the electrically conductive layer on the substrate provided with the isolation layer,completely electrically and mechanically separating the fastening anchor from the substrate by a sequence of etching processes in connection with at least one passivation step so as to form the isolation gaps, the connection to the fastening anchor created by the first structure of the electrically conductive layer being maintained at one site at least in the way of a bridge so that the fastening anchor is secured into position as a result thereof.3. The method according to claim 1, wherein, to completely electrically and mechanically separate fastening anchor and/or spring part and/or mass part from the substrate except for the mechanical fixation of the functional unit or of the fastening anchor through the first structure of the electrically conductive layer, the following processes are carried out:etching wells into the substrate for the purpose of forming the first lateral isolation gaps using a photolithographically manufactured mask concurrently with the mask produced through the masking effect of the patterned surface layers,depositing a passivation layer on vertical and horizontal areas of the first lateral isolation gaps,etching the passivation layer for the purpose of removing it from at least the bottom of the first lateral isolation gaps, undercutting the substrate material under the regions of the to be produced functional unit or fastening anchor and, if required, of the spring part and/or the mass part that are protected both on the side areas and on the surface thereof in order to produce the second isolation gap between substrate and base of functional unit or fastening anchor and/or spring part and/or mass part.4. The method according to claim 2, wherein the isolation layer is produced by thermal oxidation of silicon or by chemical vapour phase deposition.5. The method according to claim 1, wherein, to create the a first lateral isolation gap, wells are etched into the substrate normal to the substrate surface by means of reactive ion etching processes.6. The method according to claim 5, wherein, simultaneously with or after etching of the wells into the substrate, a defined isotropic etching of the substrate material is performed by means of reactive ion etching processes in the substrate to completely electrically isolate the substrate from the electrically conductive layer.7. The method according to claim 1, wherein, to etch at least one first lateral isolation gap into the substrate, gases containing fluorine and carbon are utilized.8. The method according to claim 1, wherein, to etch a plurality of isolation gaps into the substrate, gases containing chlorine or fluorine are utilized.9. The method according to claim 1, further comprising using dry etching processes, wet chemical etch solutions, or a combination of dry etching processes and wet chemical etch solutions for defined isotropic etching.10. The method according to claim 1, wherein, after undercutting material from the substrate, a passivation layer is completely removed from a surface of the electrically conductive layer.11. The method according to claim 10, wherein the passivation layer comprises an organic material which, after isotropic etching, is completely removed from the surface of the electrically conductive layer by means of a dry etching process.12. The method according to claim 10, wherein the passivation layer comprises a plasma polymer.13. The method according to claim 1, wherein the electrically conductive layer is subsequently placed in electric contact through peripheral connections.14. The method according to claim 1, wherein the electrically conductive layer is placed in electric contact through peripheral connections that are already provided in the surrounding substrate.15. The method according to claim 1, wherein, after the electrically conductive layer has been applied and patterned, an additional second passivation layer is deposited which is patterned subsequently, immediately prior to etching wells into the substrate with the same mask as used for etching the first lateral isolation gaps into the substrate.16. The method according to claim 10, wherein the additional second passivation layer is removed from at least the surface of the electrically conductive layer together with the passivation layer.