Vacuum pressure sensor including contaminant shield

Abstract

A vacuum pressure sensor includes an electrode and a diaphragm forming a capacitive structure. The sensor further includes a housing defining a sensor cavity and including a support structure configured to support the capacitive structure within the sensor cavity. The diaphragm is located in a diaphragm plane and the electrode extends substantially parallel to the diaphragm on a first side of the diaphragm plane. The housing further includes an inlet disposed on a second side of the diaphragm plane and configured to be in fluid communication with the measured environment. The sensor further includes a contaminant shield disposed in the sensor cavity between the inlet and the capacitive structure, where the contaminant shield is configured to provide at least one fluid communication path from the inlet to the diaphragm, and where each of the at least one fluid communication path crosses the diaphragm plane at least twice.

Description

Technical Field

[0001] The present disclosure generally relates to vacuum pressure sensors, and in particular, to vacuum pressure sensors including a contaminant shield. Background Art

[0002] Industrial systems and processes for depositing and removing materials from a substrate, such as semiconductor manufacturing processes, typically require a vacuum chamber with a tightly controlled environment for supplying the required reactive gases at controlled concentrations, pressures, temperatures, and flow rates. Examples of such applications and processes include various types of deposition and etching processes, as well as sterilization processes.

[0003] In these industrial systems, sensors are required to measure process parameters including pressure, temperature, and gas flow rate. For example, capacitance diaphragm gauges are known in the art, and simplified examples are shown in FIGS. 1 and 2. Referring to FIG. 1, a vacuum pressure sensor 100 includes a housing 102 defining a sensor cavity 104 having a capacitance structure 108 disposed therein. A conduit forms an inlet 106 and is hermetically connected to the housing 102, and provides fluid communication of a medium from the environment being measured (e.g., a vacuum chamber, not shown) to the sensor cavity 104, as indicated by the thick arrow. The capacitance structure 108 includes a conductive flexible diaphragm 108 that is supported at a fixed distance from an electrode 110 located in a permanently sealed vacuum environment 112, thereby forming a capacitor. In a nominal state (i.e., undeflected), the diaphragm 108 lies in a plane 114 that bisects the sensor cavity 104, such that the capacitance structure 108 has a known capacitance value. When the diaphragm 108 is exposed to a varying pressure from the environment being measured, the diaphragm 108 deflects to a varying extent, thereby changing the capacitance of the capacitance structure. Using known components and circuitry, this change in capacitance can be measured such that the pressure in the environment being measured can be determined.

[0004] The industrial systems typically produce reaction by-products, such as vapors and particles, which migrate into the deployed sensor cavities and contaminate and / or corrode the sensing elements disposed therein. These contaminants typically take the form of deposited films and particles deposited on the sensing elements, such as the sensing diaphragm 108 of a capacitance sensor. If such process contamination is allowed to accumulate on or corrode the sensing elements of the sensor, the measurement accuracy and sensor output stability will degrade over time. Preventing such process contamination of the sensing elements is important for ensuring proper performance and reliability of the measurement output of the sensor, and various techniques for minimizing such contamination are known in the art.

[0005] For example, heated vacuum gauges are often used, in which the temperature of the sensor is controlled high enough to prevent condensation of vapor in the sensor cavity. While this method efficiently prevents contaminants from condensation, such heated gauges are more expensive than non-heated gauges and do not prevent particulate contaminants from entering and affecting the sensor element.

[0006] As another example, discrete in-line filters have been used to capture particulate contaminants in the conduit leading to the sensor. However, such filters involve additional system components and may not be effective for condensing vapor before it reaches the sensing element of the sensor.

[0007] Additionally, routine maintenance has been employed to remove contaminants in the sensing cavity of the sensor by flushing with a solvent. However, this technique requires the system to be shut down for maintenance, and its effectiveness highly depends on the specific solvent used and the technique employed for such flushing. If an inadequate or inappropriate solvent is used, or an inappropriate flushing technique is employed, it may also lead to damage or deterioration of the sensor.

[0008] The use of a shielding barrier or plasma shield is a common technique for protecting the sensing diaphragm from direct exposure to process contaminants, examples of which are shown in FIGS. 1 and 2. In FIG. 1, a disk-shaped shield 120 is deployed within the sensor cavity 104 and is configured such that it prevents line-of-sight communication of the incoming fluid medium from the conduit 106 to the diaphragm. Similarly, in FIG. 2, a sensor 200 (which includes a housing, conduit, and sensing structure substantially the same as those shown in FIG. 1) includes a helical shield 220 deployed within the input conduit and again prevents line-of-sight communication from the measured environment to the sensor cavity. Although such shields 120, 220 provide a form of protection as a primary shield against most contaminants, they still leave significant paths around such shields, which results in secondary contamination exposure of the sensing diaphragm area.

[0009] Thus, a technique that overcomes the above disadvantages of the prior art would be a welcome addition to the prior art. SUMMARY OF THE INVENTION

[0010] The above disadvantages are solved by providing a vacuum pressure sensor according to the present disclosure. In one embodiment, such a sensor includes electrodes and a diaphragm that form a capacitive structure. The sensor further includes a housing that defines a sensor cavity and includes a support structure configured to support the capacitive structure within the sensor cavity. The diaphragm is located in a diaphragm plane and the electrodes extend generally parallel to the diaphragm on a first side of the diaphragm plane. The housing further includes an inlet that is provided on a second side of the diaphragm plane and is configured to communicate with an ambient fluid to be measured. The sensor further includes a contaminant shield disposed in the sensor cavity between the inlet and the capacitive structure, wherein the contaminant shield is configured to provide at least one fluid communication path from the inlet to the diaphragm, and wherein each of the at least one fluid communication paths crosses the diaphragm plane at least twice.

[0011] In one embodiment, the housing and the contaminant shield are formed of a corrosion-resistant material, such as INCONEL or 316L stainless steel.

[0012] In one embodiment, the contaminant shield is mounted on the support structure.

[0013] In one embodiment, each of the at least one fluid communication paths is provided in part by a hole formed in the contaminant shield on the first side of the diaphragm plane.

[0014] In one embodiment, the contaminant shield includes a lower wall that extends generally parallel to the diaphragm plane and on a second side of the diaphragm plane, and further includes side walls that extend from the lower wall such that distal edges of the side walls terminate on the first side of the diaphragm plane.

[0015] In one embodiment, the support structure includes an undercut region that extends generally parallel to the diaphragm plane and on a first side of the diaphragm plane to define a dorsal surface of the support structure. Further for this embodiment, the contaminant shield may include a lower wall that extends generally parallel to the diaphragm plane and on a second side of the diaphragm plane, side walls that extend from the lower wall to the first side of the diaphragm plane, and an upper wall that extends generally parallel to the diaphragm plane from the side walls, wherein the upper wall is disposed between the housing and the dorsal surface of the support structure, and wherein the upper wall includes at least one hole that defines at least one fluid communication path. Still further for this embodiment, the contaminant shield may be formed of an upper shield section and a lower shield section, wherein the upper shield section is provided as part of the support structure or wherein the upper shield section includes the upper wall. Additionally, the upper shield section may include at least a portion of the side walls.

[0016] In one embodiment, one of the at least one fluid communication path includes at least one labyrinth feature that partially blocks the fluid communication path. The at least one labyrinth feature structure can be provided on the housing and / or the contaminant shield. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments in conjunction with the accompanying drawings, in which:

[0018] FIG. 1 is a schematic cross-sectional view showing a first embodiment of a vacuum pressure sensor including a contaminant shield according to the prior art;

[0019] FIG. 2 is a schematic cross-sectional view showing a second embodiment of a vacuum pressure sensor including a contaminant shield according to the prior art;

[0020] Figure 3 is a schematic cross-sectional view showing a first embodiment of a vacuum pressure sensor including a contaminant shield according to the present disclosure;

[0021] Figure 4 is a schematic cross-sectional view showing a second embodiment of a vacuum pressure sensor including a contaminant shield according to the present disclosure;

[0022] Figure 5 is a schematic cross-sectional view showing a third embodiment of a vacuum pressure sensor including a contaminant shield according to the present disclosure; and

[0023] Figure 6 is a schematic cross-sectional view showing a fourth embodiment of a vacuum pressure sensor including a contaminant shield according to the present disclosure. DETAILED DESCRIPTION

[0024] As used herein, a phrase generally similar to "at least one of A, B, or C" is intended to be construed in a disjunctive manner, i.e., requiring A or B or C or any combination thereof, unless the context otherwise indicates or implies. Additionally, a phrase generally similar to "at least one of A, B, and C" is intended to be construed in a conjunctive manner, i.e., requiring at least one of A, at least one of B, and at least one of C, unless the context otherwise indicates or implies. Further still, the term "substantially" or similar words requiring subjective comparison are intended to mean "within manufacturing tolerances", unless the context otherwise indicates or implies.

[0025] As used herein, the phrase "operatively connected" refers to at least one functional relationship between two elements and can encompass configurations in which the two elements are directly connected to each other, i.e., without any intermediate element, or indirectly connected to each other, i.e., with an intermediate element.

[0026] As used herein, the phrase "in fluid communication" refers to an arrangement between two or more components in which fluid can flow between such components in at least one direction.

[0027] All of the vacuum pressure sensors shown in the drawings are not drawn to scale. Additionally, as is well known in the art, the various sensors shown in the figures are generally cylindrical in shape about a longitudinal axis.

[0028] Now referring to Figure 3 , a simplified illustration of a first embodiment of a vacuum pressure sensor 300 including a contaminant shield in accordance with the present disclosure is shown. The sensor 300 includes a housing 302 mounted on a support structure 304 such that an airtight sensor cavity 306 is formed therebetween. The materials for the housing 302 and the mounting structure 304 are consistent with those typically used in the art. A conduit in airtight connection with the housing 302 forms a fluid inlet 308 leading to the sensor cavity 306. In accordance with known techniques, the support structure 304 is configured to support a capacitive structure 310 including a diaphragm 312 and electrodes 314 within the sensor cavity 306. In a nominal undeflected state, the diaphragm 312 lies within a diaphragm plane 316. Throughout the present disclosure, the region above the diaphragm plane as depicted in the current drawings is considered the first side of the diaphragm plane, and the region below the diaphragm plane as depicted in the current drawings is considered the second side of the diaphragm plane.

[0029] Again, note that Figure 3 the structure shown in Figure 3 is not drawn to scale; for example, for a diaphragm 312 having a 1 inch (25.4 mm) diameter, the spacing between the diaphragm 312 and the electrodes 314 would be approximately 0.005 inches (0.13 mm). Components and circuitry providing electrical communication with the diaphragm 312 and the electrodes 314 are well known in the art and are not shown in

[0030] The sensor 300 further includes a contaminant shield 320 disposed within the sensor cavity 306 between the inlet 308 and the capacitive structure 310 such that line-of-sight communication as well as fluid communication between the inlet 308 and the capacitive structure 310 is blocked. The contaminant shield 320 is configured to provide at least one fluid communication path from the inlet 308 to the diaphragm 312 while ensuring that the at least one fluid communication path is tortuous, thereby reducing the likelihood of contaminants reaching the diaphragm 312. In the context of the present disclosure, the term "tortuous" means that the contaminant shield according to all embodiments of the present disclosure is configured to ensure that the at least one fluid communication path provided thereby crosses the diaphragm plane at least twice, as described in further detail below. This configuration will tend to substantially surround the capacitive structure 310 or isolate the capacitive structure 310 from the inlet 308, thereby making it more difficult for contaminants to reach the capacitive structure 310 while still providing a relatively compact structure for the sensor 300. This configuration also has the further benefit of isolating the capacitive structure 310 from environmental factors (e.g., barometric pressure, thermal transients, etc.), thereby improving the accuracy and consistency of the sensor 300. Various examples of contaminant shields meeting these criteria are shown in the various embodiments described herein.

[0031] Generally, the contaminant shield according to the present disclosure is preferably made of a corrosion-resistant material (specifically, a material resistant to particular industrial process chemicals and contaminants to which it may be exposed). Examples of such materials include "INCONEL" alloys or 316L stainless steel. Other materials suitable for this purpose will be apparent to those skilled in the art.

[0032] In Figure 3 a first embodiment, the contaminant shield 320 is formed as a cup-like structure having a lower or bottom wall 322 and an annular side wall 324 extending generally perpendicularly from the perimeter of the lower wall 322. The diameter of the contaminant shield 320 is such that it is greater than the outer diameter of the capacitive structure 310 but less than the inner diameter of the housing 302, thereby forming a flow path as described in further detail below. As Figure 3As shown, the contaminant shield 320 is mounted on the support structure 304 using known techniques (such as welding), although this is not required, i.e., in an alternative embodiment, the contaminant shield 320 may be mounted on the housing 302 via, for example, suitable support posts or the like. In the illustrated embodiment, the lower wall 322 and the lateral wall 324 are integrally formed as a single unit. As further shown, the lower wall 322 is configured to extend generally parallel to the diaphragm plane 316. A feature of the contaminant shield 320 is that the lower wall 322 is deployed on the second (lower) side of the diaphragm plane 316, and the lateral wall 324 extends from the lower wall 322, across the diaphragm plane 316 and has a distal edge (relative to the lower wall 322) that terminates at a point on the first side of the diaphragm plane 316. In this way, the configuration, placement, and sizing of the contaminant shield 320 relative to the configuration, placement, and sizing of the housing 302 and the capacitive structure 310 results in the establishment of a fluid communication path that is forced to cross the diaphragm plane 316 at least twice.

[0033] In combination with the housing 302, the bottom wall 322 and the lateral wall 324 form a first horizontal flow path 326 and a first (annular) vertical flow path 328. In a similar manner, and in combination with the support structure 304 and the capacitive structure 310, the bottom wall 322 and the lateral wall 324 also form a second (annular) vertical flow path 330 and a second horizontal flow path 332. In the illustrated embodiment, the lateral wall 324 includes at least one hole 334 that provides fluid communication, although restricted, between the respective vertical flow paths 328, 330. In this way, fluid communication between the horizontal flow paths 326, 332, the vertical flow paths 328, 330, and the at least one hole 334 produces at least one fluid communication path from the inlet 308 to the diaphragm 312. As indicated by the thick arrows, the medium from the measured environment can thus flow through the inlet 308, into the first horizontal flow path 326, and thereafter into the first vertical flow path 328, thereby crossing the diaphragm plane 316 for the first time. The medium can continue to flow through the hole 334, into the second vertical flow path 330 and into the second horizontal flow path 332, thereby crossing the diaphragm plane 316 for the second time. The medium present in the second horizontal flow path 332 impinges on the diaphragm 312, thereby allowing measurement of the pressure within the measured environment. Formed in this way, this at least one fluid communication path from the inlet 308 to the diaphragm 312 establishes a relatively long path and surface, which provides a greater opportunity for particles and condensate to accumulate before encountering the diaphragm 312.

[0034] As Figure 3As further depicted in , the support structure 304 may optionally have an undercut region 340 formed therein such that the undercut region 340 extends behind the capacitive structure 310 and creates a backside surface 342 of the capacitive structure 310. Techniques for forming such an undercut region are well known to those skilled in the art. The presence of the undercut region 340 may provide additional surface area where particles or condensate may settle before encountering the diaphragm 312. Additionally, in an alternative embodiment described below, the undercut region 340 may be configured to receive a portion of a contaminant shield.

[0035] Now referring to Figure 4 , a simplified illustration of a second embodiment of a vacuum pressure sensor 400 including a contaminant shield in accordance with the present disclosure is shown. In Figure 4 , like reference numerals refer to like structures as compared to Figure 3 . In this second embodiment, in addition to the housing 302 and the support structure 404, the sensor cavity 306 is further defined by an upper housing 450. Here, the support structure 404 is modified to provide a larger undercut region 440 such that, as compared to the first embodiment 300 of Figure 3 , the backside surface 442 of the support structure 404 is further located within the sensor cavity 306.

[0036] The upper housing 450 spans the diameter of the opening (opposite the inlet 308) formed by the housing 302 and is attached to the terminal edge of the housing 302 in an airtight manner using known techniques. The opening is formed centrally in the upper housing 450 such that the support structure 404 can be attached to the upper housing 450 in an airtight manner using known techniques. The upper housing 450 further includes a flange 452 that extends into the undercut region 440 opposite the backside surface 442 of the support structure 404. The annular portion 454 of the flange 452 extends downward (as depicted in Figure 4 ), and the radially extending portion 456 of the flange 452 extends generally parallel to the diaphragm plane 316 such that the peripheral edge of the radially extending portion 456 has a diameter greater than the outermost diameter of the support structure 404 but less than the inner diameter of the housing 302. In this manner, the flange 452 creates a third horizontal flow path 460 and further cooperates with the backside surface 442 of the support structure 404 to create a fourth horizontal flow path 462.

[0037] Additionally, the flange 452 has at least one hole 434 formed therein, providing fluid communication between the third and fourth horizontal flow paths 460, 462. In the illustrated embodiment, the at least one hole 434 is formed in the annular portion 454 of the flange 452. However, this is not required as the at least one hole 434 may alternatively be formed in the radially extending portion 456 of the flange 452.

[0038] In this embodiment, the contaminant shield 420 again has a cup-like shape and includes a lower wall 422 disposed on a second side of the diaphragm plane 316 and a lateral wall 424 extending therefrom to a first side of the diaphragm plane 316. Different from Figure 3 the first embodiment, the lateral wall 424 does not have a hole formed therein. Additionally, the contaminant shield 420 is mounted on a radially extending portion 456 of the flange 452. In this manner, the radially extending portion 456 effectively serves as an upper wall of the contaminant shield.

[0039] Constructed in this way, the established at least one fluid communication path includes (in order from the inlet 308 to the diaphragm 312) a first horizontal flow path 326, a first vertical flow path 328, a third horizontal flow path 460, at least one hole 434, a fourth horizontal flow path 462, a second vertical flow path 330, and a second horizontal flow path 332. By adding the third and fourth horizontal flow paths 460, 462, the total length of the at least one fluid communication path is substantially increased, thereby providing additional isolation of the capacitive structure 310 from the inlet 308 and an even greater opportunity for particles and condensate to accumulate before encountering the diaphragm 312.

[0040] Now referring to Figure 5 , a simplified illustration of a third embodiment of a vacuum pressure sensor 500 including a contaminant shield according to the present disclosure is shown. In Figure 5 , like reference numerals refer to similar structures as compared to Figure 3 . In this third embodiment, the housing 302 again has a cup-like structure. However, in this case, the housing 302 is inverted such that it is mounted on a housing base 503, which in turn has an inlet 308 mounted thereon. Thus, the sensor cavity 306 is defined by the housing base 503, the housing 502, and a support structure 504 (in a central opening formed in the housing 502) mounted on the housing 502. Again, the support structure 504 (as compared to Figure 3 ) is modified to provide a larger undercut area 540 such that, as compared to the first embodiment 300 of Figure 3 , the back side surface 542 of the support structure 504 is further located within the sensor cavity 306.

[0041] In the third embodiment, the contaminant shield 520 generally resembles that described above with respect to Figure 3 and Figure 4The lower wall 522 and the lateral wall 524 of those described. However, in this case, the contaminant shield further includes an upper wall 526 that extends radially inward from the upper terminal of the lateral wall 524. The upper wall 526 includes a central opening that is configured to receive a portion of the support structure 504 such that the upper wall 526 is attached to the support structure 504 in an airtight manner using known techniques. The upper wall 526 further includes at least one hole 534.

[0042] As Figure 5 Further shown, the contaminant shield 520 is formed by two sections: a lower shield section 570 and an upper shield section 572, which can be attached to each other in an airtight manner using known techniques. As shown, the upper shield section 572 provides 526 and a portion of the side wall 524, while the lower shield section 570 provides another portion of the side wall 524 and the lower wall 522. However, it should be understood that the upper shield section 570 and the lower shield section 572 can be configured to respectively provide different portions of the respective walls 522, 524, 526 that define the contaminant shield 520.

[0043] In any case, this sectionalized construction of the contaminant shield 520 makes the assembly of the sensor 500 simpler because the upper shield section 572 can be first attached to the support structure 504. Thereafter, the lower shield section 570 is attached to the upper shield section 572 such that the contaminant shield 520 substantially surrounds the capacitive structure 310. Thereafter, the assembly including the support structure 504 and the contaminant shield 520 is mounted on the housing 502, which is subsequently attached to the housing base 503.

[0044] In Figure 5 the third embodiment, similar to Figure 4 the embodiment, the at least one fluid communication path includes (in order from the inlet 308 to the diaphragm 312) a first horizontal flow path 326, a first vertical flow path 328, a third horizontal flow path 560, at least one hole 534, a fourth horizontal flow path 562, a second vertical flow path 330, and a second horizontal flow path 332. By adding the third and fourth horizontal flow paths 560, 562, the total length of the at least one fluid communication path is again substantially increased, thereby providing additional isolation of the capacitive structure 310 from the inlet 308 and an even greater opportunity for particles and condensate to accumulate before encountering the diaphragm 312.

[0045] Now referring to Figure 6 FIG., a fourth embodiment of a vacuum pressure sensor 600 is shown, which is generally similar to Figure 6A third embodiment. However, in this fourth embodiment, a partial barrier in the form of a labyrinth feature 680 is provided within the first horizontal flow path 326. Although depicted within the first horizontal flow path 326, it should be understood that such a labyrinth feature 680 may alternatively or additionally be provided within any of the other horizontal or vertical flow paths described in any of the presently disclosed embodiments. In the example shown, each of the labyrinth features 680 includes a pair of upwardly extending protrusions 682 formed in the housing base 503 and downwardly extending protrusions 684 formed in the lower wall 522 of the contaminant shield 620 and interdigitated between the upwardly extending protrusions 682. Formed in this way, the labyrinth feature 680 again increases the total distance of the at least one fluid communication path and provides additional surface area for the capture of contaminants. It should be noted that although shown in the form of including a single interdigitated labyrinth feature 680, this is not a requirement, as each of the labyrinth features 680 may include multiple interdigitations, e.g., three upwardly extending protrusions 682 and two downwardly extending protrusions 684 interdigitated therebetween. As yet another alternative, each of the labyrinth features 680 may be more simply constructed as they may include only a single upwardly or downwardly extending protrusion 682, 684.

[0046] While various embodiments in accordance with the present disclosure have been described in connection with their specific implementations, it will be apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, Figures 3 to 6 the various housing embodiments shown may be interchanged where possible. Accordingly, the preferred embodiments of the invention set forth herein are intended to be illustrative rather than limiting, provided that their variations fall within the scope of the appended claims and their equivalents.

Claims

1. A vacuum pressure sensor comprising an electrode and a diaphragm forming a capacitive structure, the sensor comprising: a housing defining a sensor cavity and including a support structure configured to support the capacitive structure within the sensor cavity such that the diaphragm is located in a diaphragm plane and the electrodes extend substantially parallel to the diaphragm on a first side of the diaphragm plane, the housing further including an inlet disposed on a second side of the diaphragm plane and configured to communicate with an ambient fluid being measured; as well as A contaminant shield is disposed in the sensor cavity between the inlet and the capacitive structure, wherein the contaminant shield is configured to provide at least one fluid communication path from the inlet to the diaphragm, wherein each of the at least one fluid communication path crosses the plane of the diaphragm at least twice. 2 . The vacuum pressure sensor of claim 1 , wherein the housing and contaminant shield are formed of corrosion resistant materials.

3. The vacuum pressure sensor of claim 2, wherein the contaminant shield comprises INCONEL or 316L stainless steel.

4. The vacuum pressure sensor of claim 1, wherein the contamination shield is mounted on the support structure.

5. The vacuum pressure sensor of claim 1, wherein each of the at least one fluid communication path is provided in part by an aperture formed in the contamination shield on the first side of the diaphragm plane.

6. The vacuum pressure sensor of claim 1 , wherein the contaminant shield includes a lower wall and further includes a lateral wall, the lower wall being substantially parallel to the diaphragm plane and extending on the second side of the diaphragm plane, the lateral wall extending from the lower wall such that a distal edge of the lateral wall terminates on the first side of the diaphragm plane.

7. The vacuum pressure sensor of claim 1, wherein the support structure includes an undercut region substantially parallel to the diaphragm plane and extending on the first side of the diaphragm plane to define a backside surface of the capacitive structure.

8. The vacuum pressure sensor of claim 7 , wherein the contaminant shield comprises a lower wall substantially parallel to the diaphragm plane and extending on the second side of the diaphragm plane, a lateral wall extending from the lower wall to the first side of the diaphragm plane, and an upper wall extending from the lateral wall substantially parallel to the diaphragm plane, wherein the upper wall is disposed between the housing and the back surface of the support structure, and Wherein the upper wall includes at least one hole defining the at least one fluid communication path. 9 . The vacuum pressure sensor of claim 8 , wherein the contamination sensor is formed by an upper shield segment and a lower shield segment.

10. The vacuum pressure sensor of claim 9, wherein the upper shield section is provided as part of the support structure.

11. The vacuum pressure sensor of claim 9, wherein the upper shield section includes the upper wall.

12. The vacuum pressure sensor of claim 11, wherein the upper shield segment comprises at least a portion of the lateral wall.

13. The vacuum pressure sensor of claim 1, wherein one of the at least one fluid communication path includes at least one labyrinth feature that partially blocks the fluid communication path.

14. The vacuum pressure sensor of claim 13, wherein the at least one labyrinth feature is disposed on the housing.

15. The vacuum pressure sensor of claim 13, wherein the at least one labyrinth feature is disposed on the contamination shield.

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