Manufacturing method for a micromechanical pressure sensor device and corresponding micromechanical pressure sensor device

Abstract

A manufacturing method for a micromechanical sensor device and a corresponding micromechanical sensor device. The method includes providing a substrate including at least one first through a fourth parallel trenches; depositing a layer onto the front side, the trenches being sealed, and structuring the layer, contact structures being formed in the layer above the second and fourth trenches; oxidizing of outwardly free-standing side surfaces of the contact structures as well as of the second and fourth trenches, at least in areas; depositing and structuring a first metallic contacting material, the contact structures being filled with the first metallic contacting material, at least in areas; opening the second trench and the fourth trench; galvanic deposition of a second metallic contacting material into the second and fourth trenches, resulting in the formation of a pressure-sensitive capacitive capacitor structure; and opening the first trench from the front side of the substrate.

Claims

1. A manufacturing method for a micromechanical pressure sensor device, comprising: A) providing a substrate including at least one first through a fourth trench, which run in parallel to one another at a distance to one another, starting from a front side of the substrate; B) depositing a layer onto the front side, the at least first through fourth trenches being sealed by the layer, and structuring the layer, contact structures being formed in the layer above the second and fourth trenches; C) oxidizing outwardly free-standing side surfaces of the contact structures and of the second and fourth trenches; D) depositing and structuring a first metallic contacting material, the contact structures being filled with the first metallic contacting material; E) opening the second trench and the fourth trench from a rear side of the substrate; F) galvanically depositing a second metallic contacting material via the rear side of the substrate into the second and fourth trenches, the second metallic contacting material being deposited on the oxidized side surfaces, resulting in the formation of a pressure-sensitive capacitive capacitor structure; and G) opening the first trench from the front side of the substrate, a pressure access being formed for the pressure-sensitive capacitive capacitor structure.

2. The manufacturing method as recited in claim 1, wherein an N-lattice is implemented on the front side of the substrate for forming the at least first through fourth trenches.

3. The manufacturing method as recited in claim 1, wherein a porous silicon is used for the substrate.

4. The manufacturing method as recited in claim 1, wherein at least one of an electronic evaluation unit and a bipolar processor, is integrated into the substrate on the substrate level.

5. The manufacturing method as recited in claim 1, wherein a monocrystalline silicon is used for the layer.

6. The manufacturing method as recited in claim 1, wherein the side surfaces, which are oxidized, are used for depositing the first metallic contacting material and the second metallic contacting material.

7. The manufacturing method as recited in claim 1, wherein when the first metallic contacting material is deposited and structured, metallic strip conductors are formed, and the metallic strip conductors are used for the galvanic deposition of the second metallic contacting material.

8. The manufacturing method as recited in claim 7, wherein the metallic strip conductors are at least partially removed, after the galvanic deposition of the second metallic contacting material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional features and advantages of the present invention are explained below based on specific embodiments with reference to the figures.

(2) FIGS. 1A through 8A show schematic cross-sectional views for explaining a manufacturing method for a micromechanical pressure sensor device and a corresponding micromechanical pressure sensor device according to a first specific embodiment of the present invention.

(3) FIGS. 1B, 3B through 5B, 7B and 8B show schematic top views corresponding to FIGS. 1A, 3A through 5A, 7A and 8A.

(4) FIGS. 4A, 4B, 7A show schematic enlargements of corresponding FIG. 4A and FIG. 7A.

(5) FIG. 9 shows a schematic top view for elucidating a micromechanical pressure sensor device according to a second specific embodiment of the present invention.

(6) FIGS. 10A through 14A show schematic cross-sectional views for elucidating a method for producing an exemplary first trench and an exemplary second trench based on an APSM technology, FIGS. 10B through 14B being corresponding top views of FIGS. 10A through 14A.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(7) Identical reference symbols in the figures denote identical elements or elements having an identical function.

(8) The steps of the manufacturing method for a micromechanical pressure sensor device shown in the drawings show at least one first through fifth trench G1; G2; G3; G4; G5. This is intended to be understood as an additional specific embodiment of the micromechanical pressure sensor device. The symmetrical design of first trench G1 and of fifth trench G5 makes it in particular possible to carry out a homogeneous pressure measurement.

(9) Furthermore, a mechanical stress may be homogeneously equalized during operation of the micromechanical pressure sensor device.

(10) FIGS. 1A through 8A are schematic cross-sectional views for elucidating a manufacturing method for a micromechanical pressure sensor device and a corresponding micromechanical pressure sensor device according to a first specific embodiment of the present invention.

(11) In FIG. 1A, reference numeral 1 denotes a substrate including at least one first through one fifth trench G1; G2; G3; G4; G5. Trenches G1; G2; G3; G4; G5 extend from a front side V1 of substrate 1 in parallel to one another. As shown in FIG. 1A and FIG. 1B, at least first through fifth trenches G1; G2; G3; G4; G5 are freely accessible from front side V1 of substrate 1. An N-lattice N1 may in particular be implemented on front side V1 of substrate 1 (see FIGS. 10A through 13A).

(12) In FIG. 2A, reference numeral 1 denotes an alternative substrate 1, which has an electronic evaluation unit A1 on its front side. Alternatively, electronic evaluation unit A1 may be combined with a bipolar processor A1 or replaced by bipolar processor A1.

(13) As shown in FIGS. 3A and 3B, a layer S1 is deposited onto front side V1 of substrate 1. In this case, first through fifth trenches G1; G2; G3; G4; G5 are sealed. In the present context, sealing may also be understood to be a hermetic sealing of at least first through fifth trenches G1; G2; G3; G4; G5.

(14) As shown in FIGS. 4A and 4B, layer S1 is structured, contact structures 20; 30 being formed in layer S1 above second and fourth trenches G2; G4.

(15) FIG. 4A is a corresponding enlargement of FIG. 4A. As shown in FIG. 4A, contact structures 20; 30 are formed above second and fourth trenches G2; G4 in such a way that contact structures 20; 30 do not extend into first trench G1, third trench G3 and fifth trench G5.

(16) FIG. 4B shows another enlargement of FIG. 4A (represented by the oval circle in the area of fourth trench G4 of FIG. 4A).

(17) FIG. 4B shows one of the correspondingly outwardly free-standing side surfaces 40 of contact structures 20; 30 and of second and fourth trenches G2; G4. For example, the oxide layer occurring on side surfaces 40 of contact structures 20; 30 and of second and fourth trenches G2; G4 may be a silicon oxide.

(18) As shown in FIG. 5A, a first metallic contacting material M1 is deposited and structured. In this case, contact structures 20; 30 are filled with first metallic contacting material M1, at least in areas.

(19) As shown in FIGS. 5A and 5B, after first metallic contacting material M1 has been deposited at least in areas, metallic strip conductors LB1 are formed, it being possible for metallic strip conductors LB1 to be used for the subsequent galvanic deposition of a second metallic contacting material M2. Furthermore, during the structuring of first metallic contacting material M1, bonding pads P1 and electrodes E2; E4 are formed on layer S1. Strip conductors LB1 are electrically insulated from one another and each of them contacts electrodes E2; E4, which are produced when first metallic contacting material M1 is structured.

(20) As shown in FIG. 6A, second trench G2 and fourth trench G4 are opened from a rear side R1 of substrate 1. This may take place in particular with the aid of trench etching. In other words, first trench G1, third trench G3 and fifth trench G5 remain sealed or have a vacuum.

(21) As shown in FIGS. 7A and 7A, a second metallic contacting material M2 is deposited galvanically via rear side R1 of substrate 1 into second and fourth trenches G2; G4. In this case, second metallic contracting material M2 is deposited on oxidized side surfaces 40 (see also FIG. 4B), resulting in the formation of a pressure-sensitive capacitive capacitor structure K1.

(22) As shown in FIG. 7B, contact structures 20; 30 of second trench and fourth trench G4 are electrically separated from one another.

(23) As shown in FIG. 8A, first trench G1 and fifth trench G5 are opened from front side V1 of substrate 1, pressure accesses D1; D5 being formed for pressure-sensitive capacitive capacitor structure K1.

(24) As shown in FIG. 8B, corresponding pressure accesses D1; D5 extend above first trench G1 and fifth trench G5 and in parallel to pressure-sensitive capacitive capacitor structure K1 at a distance, the pressure-sensitive capacitive capacitor structure K1 being located between pressure accesses D1; D5.

(25) FIG. 9 shows a schematic top view for elucidating a micromechanical pressure sensor device according to a second specific embodiment of the present invention.

(26) As shown in FIG. 9, micromechanical pressure sensor device 100 includes four series-connected pressure sensitive capacitive capacitor structures K1; K2; K3; K4. Each of the four series-connected pressure sensitive capacitive capacitor structures K1; K2; K3; K4 includes corresponding pressure accesses D1; D5.

(27) It should be understood that the manufacturing method described here may be used, in particular, for manufacturing micromechanical pressure sensor devices including a plurality of series-connected and/or parallel-connected pressure-sensitive capacitive capacitor structures.

(28) FIGS. 10A through 13A are schematic cross-sectional views for elucidating a method for producing an exemplary first trench and an exemplary second trench based on an APSM technology according to the first or second specific embodiment of the present invention, FIGS. 10B through 13B representing corresponding top views of FIGS. 10A through 13A.

(29) FIG. 10A shows a substrate 1 having a front side V1, the N-lattice being implemented on front side V1.

(30) In order to provide first trench G1 and second trench G2, the front side is appropriately pre-structured (notches 60), so that macroscopic pores or trenches are created transversely or, in particular, perpendicularly to front side V1 of the substrate, as shown in FIG. 12A. In particular, material residues 70 of substrate 1 may remain in this case.

(31) As shown in FIG. 13A, these material residues 70 may be removed by oxidation or correspondingly by sintering (see transition from FIG. 13A to FIG. 14A), if these material residues 70 are thin enough. In this case, however, areas including material residues 70, which have appropriate wall thicknesses, are spared and form first trench G1 and second trench G2.

(32) As shown in FIG. 14A, substrate 1, which is provided for the manufacturing method described here for micromechanical pressure sensor device 100, includes N-lattice N1 and first trench G1 and second trench G2 which are shown here as an example. FIGS. 10B through 14B show corresponding top views of the schematic side representations.

(33) In other words, the production of the trenches is based in particular on the ASPM method.

(34) Using the micromechanical sensor device described here, it is in particular possible to measure a pressure of approximately 1000 millibars. This pressure range is of particular interest for customer applications.

(35) Although the present invention has been described with reference to preferred exemplary embodiments, it is not limited thereto. In particular, the above-named named materials and topologies are only exemplary and not limited to the explained examples.