METHOD FOR MANUFACTURING AT LEAST ONE MEMBRANE SYSTEM, MEMBRANE SYSTEM FOR A MICROMECHANICAL SENSOR, AND COMPONENT

Abstract

A method for manufacturing at least one membrane system for a micromechanical sensor for the calorimetric detection of gases. A wafer-shaped substrate is provided. At least one reference volume is introduced from a front side into the wafer-shaped substrate with the aid of a surface or volume micromechanical process while forming a reference membrane covering the reference volume at least in some areas. At least one measuring volume, which is adjacent to the at least one reference volume, is introduced into the substrate from a back side or the front side of the wafer-shaped substrate while forming a measuring membrane. A wafer-shaped cap substrate is applied onto the front side of the wafer-shaped substrate. A membrane system and a component are described.

Claims

1-14. (canceled)

15. A method for manufacturing at least one membrane system for a micromechanical sensor for calorimetric detection of gases, the method comprising the following steps: providing a wafer-shaped substrate; introducing at least one reference volume from a front side into the wafer-shaped substrate using a surface or volume micromechanical process while forming a reference membrane covering the reference volume at least in some areas; introducing at least one measuring volume adjacent to the at least one reference volume, into the wafer-shaped substrate from a back side or the front side of the wafer-shaped substrate while forming a measuring membrane; and applying a wafer-shaped cap substrate onto the front side of the wafer-shaped substrate.

16. The method as recited in claim 15, wherein the wafer-shaped cap substrate is applied onto the wafer-shaped substrate after the introduction of the reference volume.

17. The method as recited in claim 15, wherein the wafer-shaped cap substrate is applied onto the wafer-shaped substrate after the introduction of the at least one measuring volume.

18. The method as recited in claim 15, wherein the at least one measuring volume is introduced into the wafer-shaped substrate using: (i) dry etching, or (ii) a trench etching process, or (iii) a wet etching process.

19. The method as recited in claim 15, wherein the wafer-shaped cap substrate is applied onto the front side of the wafer-shaped substrate using: (i) anodic bonding, or (ii) eutectic bonding, or (iii) bonding with using glass frit, or (iv) adhesive bonding, or (v) soldering, or (vii) welding.

20. The method as recited in claim 15, wherein the at least one reference volume, which is open or closed in A direction of the front side of the wafer-shaped cap substrate, is formed between the reference membrane and the wafer-shaped cap substrate and/or between the measuring membrane and the wafer-shaped cap substrate. during an application of the wafer-shaped cap substrate onto the wafer-shaped substrate.

21. The method as recited in claim 15, wherein the at least one measuring volume, introduced into the wafer-shaped substrate from the front side of the wafer-shaped substrate while forming the measuring membrane, is opened in a gas-conducting manner from the back side of the wafer-shaped substrate.

22. The method as recited in claim 21, wherein the at least one measuring volume is opened on the back side in a gas-conducting manner: (i) by material removal on the back side of the wafer-shaped substrate or (ii) using a porous semiconductor structure introduced on the back side of the wafer-shaped substrate.

23. The method as recited in claim 22, wherein a porous silicon structure is removed.

24. The method as recited in claim 15, wherein a sealant is situated on the back side of the wafer-shaped substrate.

25. The method as recited in claim 15, wherein at least one resistor and at least one electrically conductive connection are placed onto the reference membrane and the measuring membrane, the wafer-shaped substrate connected to the wafer-shaped cap substrate is separated into at least two membrane systems.

26. The method as recited in claim 15, wherein the at least one reference volume is introduced from the front side into the wafer-shaped substrate using a PorSi process, with or without subsequent removal of a porous silicon, while forming the reference membrane covering the reference volume at least in some areas.

27. The method as recited in claim 15, wherein the at least one reference volume is introduced into the wafer-shaped substrate from the front side while forming the reference membrane covering the reference volume at least in some areas, and an initially closed measuring volume is introduced into the wafer-shaped substrate from the front side while forming the measuring membrane covering the measuring volume at least in some areas, using a PorSi process with or without subsequent removal of the porous silicon.

28. A membrane system for a sensor for calorimetric detection of gases, comprising a cap substrate section connected to a substrate section; at least one reference volume introduced into the substrate section, which is delimited, on one side, by a reference membrane in a direction of the cap substrate section; at least one measuring volume introduced into the substrate section, which is delimited, on one side, by a measuring membrane in a direction of the cap substrate section; wherein the reference membrane is fluid-conducting, at least in some areas, in a direction of a front side of the cap substrate section, and the measuring volume is fluid-conducting in a direction of a back side of the substrate section.

29. A component, comprising: a membrane system including: a cap substrate section connected to a substrate section; at least one reference volume introduced into the substrate section, which is delimited, on one side, by a reference membrane in a direction of the cap substrate section; at least one measuring volume introduced into the substrate section, which is delimited, on one side, by a measuring membrane in a direction of the cap substrate section; wherein the reference membrane is fluid-conducting, at least in some areas, in a direction of a front side of the cap substrate section, and the measuring volume is fluid-conducting in a direction of a back side of the substrate section.

30. The component as recited in claim 29, wherein the component is a sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG. 1 shows a schematic section through a membrane system according to a first specific embodiment of the present invention.

[0071] FIG. 2 shows a schematic section through a membrane system according to a second specific embodiment of the present invention.

[0072] FIG. 3 shows a schematic representation of a method for manufacturing a membrane system according to a first exemplary embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0073] In the figures, the same structural elements each have the same reference numerals.

[0074] FIG. 1 shows a schematic section through a membrane system 1 according to a first specific embodiment of the present invention. Membrane system 1, in this case, is a section of a wafer including a plurality of membrane systems 1, which were separated from one another with the aid of a separation process.

[0075] Membrane system 1 is designed as a system for a double-membrane chip and may be manufactured according to a manufacturing process for layers of a membrane, for example, an ONO membrane (oxide-nitride-oxide) including at least one strip conductor contained therein, for example, made up of the metal platinum, gold, silver, copper, molybdenum, or tungsten, or non-metallic, conductive layers such as polysilicon or a similar material. Alternatively, the membrane may be made up of only oxide, only nitride, or a mixture of both. System 1 encompasses a reference membrane 2, which was manufactured with the aid of a surface or volume micromechanical process or a PorSi process, the latter possibly in combination with a dry etching step for removing the porous silicon structure in a wafer-shaped substrate 4. In the process, a reference volume 6, which is delimited by reference membrane 2 in the direction of a front side V of wafer-shaped substrate 4, is brought about simultaneously. Reference membrane 2 is open at least in some areas in this case, so that a gas exchange with reference volume 6 may take place.

[0076] System 1 encompasses a wafer-shaped cap substrate 8, which was applied onto wafer-shaped substrate 4 after the manufacture of reference membrane 2. Wafer-shaped cap substrate 8 encompasses recesses 7 in the area of membranes 2, 10, which extend through wafer-shaped cap substrate 8. Areas 2 and 10 may also be connected to each other. According to the exemplary embodiment, recesses 7 include oblique edges; these may be caused by a wet etching process. Recesses 7 may also be introduced into wafer-shaped cap substrate 8 with the aid of other material-removal methods, however, such as trench etching.

[0077] Wafer-shaped cap substrate 8 is situated on wafer-shaped substrate 4 with the aid of wafer bonding utilizing glass frit. Due to wafer-shaped cap substrate 8, system 1 obtains additional stability.

[0078] Moreover, system 1 encompasses a measuring membrane 10 adjacent to reference membrane 2. Measuring membrane 10 was manufactured into wafer-shaped substrate 4 during a further processing having a so-called “face down” orientation of system 1. An etching process for generating a measuring volume 14 was used on back side R of the wafer-shaped substrate. Measuring volume 14 is designed to be open in the direction of back side R and therefore allows for an unobstructed gas flow to, but not through, measuring membrane 10. In the case of another type of etching process, which does not require face down processing, such as wet etching, or which holds system 1 at the edge, wafer-shaped cap substrate 8 may also be dispensed with, if necessary.

[0079] In the area of measuring volume 14, a sealant 15 in the form of a sealing ring 15 is situated at back side R of wafer-shaped substrate 4.

[0080] FIG. 2 shows a schematic section through a membrane system 1 according to a second specific embodiment of the present invention. In contrast to membrane system 1 according to the first exemplary embodiment, in this case, measuring volume 14 was introduced into wafer-shaped substrate 4 from front side V of wafer-shaped substrate 4 also with the aid of a surface or volume micromechanical process or a PorSi process. A so-called cloud trench etching process may also be used in this case. Ideally, thereafter, a coating with an ONO membrane and the embedded metal structure made up of platinum is carried out. As a result, measuring volume 14 is closed toward the front side and toward back side R of wafer-shaped substrate 4 and was opened, in a gas-conducting manner, toward back side R with the aid of a subsequent step, for example, with the aid of a trench etching process or another etching process. As a result, measuring volume 14 encompasses openings 16, which are situated on the back side and preferably prevent particles and moisture from entering measuring volume 14.

[0081] FIG. 3 shows a schematic representation of a method 18 for manufacturing a membrane system 1 according to a first exemplary embodiment.

[0082] In a first method step 20, a wafer-shaped substrate 4 is provided.

[0083] Wafer-shaped substrate 4 may be subsequently equipped or provided with resistors or with electrically conductive connections in the form of one or multiple coatings and its/their structuring with the aid of lithography, and the electrically conductive layer is surrounded 21 by electrically insulating layers. The conductive connections preferably form heating resistors.

[0084] Thereafter, at least one reference volume 6 is introduced 22 from a front side V into wafer-shaped substrate 4 with the aid of a surface or volume micromechanical process or a PorSi process including a dry etching step, while forming a reference membrane 2 covering reference volume 6 at least in some areas.

[0085] Alternatively or additionally, the electric lines and enveloping electrically and thermally insulating layers may also be applied onto wafer-shaped substrate 4 according to method step 21 after formation 22 of reference volume 6 and/or measuring volume 14.

[0086] In a further step 23, a wafer-shaped cap substrate 8 is applied onto wafer-shaped substrate 4 and the wafer system is turned over 24, so that a processing of back side R may be carried out. Alternatively, this step may be dispensed with.

[0087] In one step 25, at least one measuring volume 14, which is adjacent to the at least one reference volume 6, is introduced into wafer-shaped substrate 4 from back side R of wafer-shaped substrate 4 while forming a measuring membrane 10. If measuring volume 14 has already been manufactured, a gas supply or a fluid-conducting connection to measuring volume 14 may be introduced from back side R of wafer-shaped substrate 4 in this step 25.

[0088] In a final step 26, wafer-shaped substrate 4 connected to wafer-shaped cap substrate 8 may be separated into at least two membrane systems 1.