PRESSURE SENSOR HAVING AN ANTISTATIC SURFACE, AND METHOD OF MANUFACTURE

Abstract

A pressure sensor having an anti-adhesion layer, and a method for manufacturing such a pressure sensor. In this context, the pressure sensor includes a pressure sensor element, which is accommodated and/or situated in a housing of the pressure sensor. In order to protect the pressure sensor element, at least one filling material is provided, which is introduced into the housing and covers the pressure sensor element at least partially. The surface of the at least one filling material is configured to have an antistatic effect.

Claims

1. A pressure sensor, comprising: a housing; and a pressure sensor element situated in the housing, the pressure sensor element in the housing being covered at least partially by at least one filling material, the at least one filling material transmitting a pressure of an applied medium to the pressure sensor element; wherein a surface of the filling material, which is pointed at the applied medium, has an antistatic property.

2. The pressure sensor as recited in claim 1, wherein the filling material is enriched with antistatic particles.

3. The pressure sensor as recited in claim 2, wherein the antistatic particles include polyquaternium.

4. The pressure sensor as recited in claim 1, wherein at least part of the surface of the filling material has an ionic tenside anti-adhesion layer.

5. The pressure sensor as recited in claim 1, wherein the pressure sensor element is covered by a first filling material, and a layer including a second filling material, is deposited at least partially on the first filling material, the second filling material including an ionic tenside anti-adhesion layer.

6. A method for manufacturing a pressure sensor, comprising: positioning a pressure sensor element in a housing; and introducing at least one filling material into the housing, the at least one filling material covering the pressure sensor element at least partially; wherein antistatic components are introduced into the at least one filling material.

7. The method as recited in claim 6, wherein the antistatic components are introduced into the at least one filling material prior to the introduction of the filling material into the housing.

8. The method as recited in claim 6, wherein the filling material is enriched with polyquaternium.

9. The method as recited in claim 6, wherein a second filling material, which contains the antistatic components, is deposited onto a first filling material.

10. The method as recited in claim 9, wherein the second filling material includes an ionic tenside anti-adhesion layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 shows an example pressure sensor represented schematically.

[0012] FIG. 2 shows a flow chart for an example method of manufacturing the pressure sensor of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0013] The construction of a pressure sensor 100 manufactured with the aid of micromechanical methods is described, using FIG. 1; the present invention being intended to be explained in light of the construction of the pressure sensor. In this connection, a housing 150 is positioned on a substrate 110, such as a circuit board. An evaluation chip 120 and a pressure sensor element 130, which are interconnected electrically by a bond 140, are positioned in housing 150, that is, on substrate 110. Also, as an alternative, only pressure sensor element 130 may be positioned on substrate 110; or evaluation chip 120, for example, an ASIC, may be positioned on substrate 110 next to pressure sensor element 130. A first filling material 160, which covers at least the important electrical and/or electronic components of pressure sensor element 130 and, optionally, of evaluation chip 120, is introduced into housing 150, in order to prevent corrosion of the medium surrounding pressure sensor 100, due to pollutants.

[0014] In a first embodiment of the present invention, first filling material 160 includes antistatic particles or components, which prevent, in particular, charged particles from depositing or settling on its surface facing the medium to be measured.

[0015] In one alternative, second variant of the present invention, a layer of a second filling material 170 is provided on first filling material 160. In this context, this layer may cover first filling material 160 completely or only partially. This layer advantageously takes the form of a planar membrane. The antistatic effect of the surface of second filling material 170 is achieved by the use of ionic tensides, such as quaternary ammonium compounds having at least one long alkyl group.

[0016] As an option, only one of the two filling materials 160 and 170 may include antistatic elements. However, in addition, an antistatic effect with respect to the applied medium may first be generated upon the interaction of the two filling materials 160 and 170.

[0017] The manufacture of the pressure sensor 100 according to the present invention is described in light of the flow chart of FIG. 2. In a first version of the manufacturing, after the construction of the pressure sensor by micromechanical method steps in step 200, the first filling material 160 mixed with antistatic particles, components, or elements is brought into housing 150 and cured in the next step 220.

[0018] In an alternative method, in step 220, a filling material 160 is used, which does not yet have any antistatically acting parts. The antistatic particles or components are first introduced into first filling material 160, using an additional step 240.

[0019] In a further possible method, in step 220, a layer made of a second filling material 170 may be deposited after the introduction of first filling material 160. In this context, both the first and/or the second filling material 160, 170, respectively, may be provided with antistatic particles or components. As explained above, these antistatic particles or components may be introduced both prior to and after the introduction of the respective filling material.

[0020] In this context, the antistatic particles, elements or components may constitute a fraction of 0.1 to 30% of the filling material, for example, as an admixture or as a subsequent result of implantation. In one particular variant, the fraction may also be 0.5 to 5%.

[0021] In the layer made up of the second filling material, the fraction of antistatic particles, elements, or components may be between 50 and 99%. In this context, the layer may be, in particular, very thin, for example, between 100 nm and 4 μm. If the layer covers the underlying passivating gel, that is, the first filling material, completely, then sufficient flexibility of the structure made up of the two filling materials may be obtained, which means that the applied pressure may be transmitted without considerable damping or delay.

[0022] A possible method of depositing the layer of second filling material 170 is to use a spraying operation.