MICRO CHECK VALVE AND SYSTEM WITH MULTIPLE MICRO CHECK VALVES AND METHOD FOR THE PRODUCTION THEREOF

Abstract

The invention concerns a micro check valve (10) comprising a substrate body (12) having a top side (16) and an underside (14), wherein at least the top side (16) has a sealing bar (34) between a first trough (30) and a second trough (32). The substrate body (12) also has a passage (24) which leads from the underside (14) of the substrate body (12) to the top side (16) of the substrate body (12) and ends on the top side (16) of the substrate body (12) in the first trough (30). In addition arranged on the top side (16) of the substrate body (12) is a diaphragm (18) which is mounted flexibly at least in the region of the sealing bar (34) and the first and second troughs (30, 32). The diaphragm (18) also has at least one through opening (42) arranged above the second trough (32).

The invention further concerns a system having a plurality of micro check valves (10) and a method for the production thereof.

Claims

1. A micro check valve comprising a substrate body (12) having a top side (16) and an underside (14), wherein the top side (16) includes a first trough (30) and a second trough (32) with a sealing bar (34) between the first trough and the second trough, and the substrate body (12) has at least one passage (24) which leads from the underside (14) of the substrate body (12) to the top side (16) of the substrate body (12) and ends in the first trough (30), and arranged on the top side (16) of the substrate body (12) is a deposited diaphragm (18) which is flexible at least in the region above the first trough (30), the second trough (32) and the sealing bar (34) in order to move at least in the direction of a normal vector (36) to the surface (16) of the substrate body (12) with respect to the substrate body, and the diaphragm (18) has at least one through opening (42) arranged in the region of the diaphragm (18), that is arranged above the second trough (32).

2. A micro check valve according to claim 1 wherein the first trough (30) is in the form of a first, preferably round, in particular circular, recess in the substrate body (12) and the second trough (32) is in the form of a second, preferably annular, in particular circular-annular, recess extending around the first recess in the substrate body (12) and the first trough (30) is separated from the second trough (32) extending around same by the sealing bar (34), wherein the sealing bar (34) is preferably annular, in particular circular-annular.

3. A micro check valve according to claim 1 or claim 2 wherein the first trough (30) with the diaphragm (18) defines an inner chamber (20) and the second trough (32) with the diaphragm (18) defines an outer chamber (22) and the sealing bar (34) forms a sealing means adapted together with the diaphragm (18) substantially to prevent a fluid flow and/or aerosol flow between the inner chamber (20) and the outer chamber (22).

4. A micro check valve according to one of the preceding claims wherein the micro check valve (10) has an opened and a closed state and is adapted to assume the opened state when a pressure difference of a fluid or aerosol between the pressure in the passage (24) and a pressure above the diaphragm (18) is at or over a predefined minimum pressure difference and to assume a closed state when the pressure difference is beneath the minimum pressure difference.

5. A micro check valve according to one of the preceding claims wherein at its top side the sealing bar (34) defines a plane, namely a sealing surface, which is deeper in the substrate body (12) than the plane which is formed by the top side (16) of the substrate body (12) and which is at least outside an outside diameter (48) of the second trough (32), preferably an outer trough edge (47).

6. A micro check valve according to one of the preceding claims wherein the diaphragm (18) has a plurality of through openings (42) arranged above the second trough (32) distributed in such a way as to produce a plurality of predefined spray directions and/or a predefined preferential spray direction of a fluid or aerosol passed through the through openings (42).

7. A micro check valve according to one of the preceding claims wherein at least one or all through openings (42) are round and/or at least one or all through openings (42) are oval and/or at least one or all through openings (42) are trapezoidal, angular, triangular, polygonal with rounded corners.

8. A micro check valve according to one of the preceding claims wherein the micro check valve (10) has at least one spring arm (120) having a first end and a second end, wherein the first end is directly or indirectly connected to the diaphragm (18) in the region in which the diaphragm (18) is moveable and the second end is directly or indirectly connected to the substrate body (12) and the spring arm (120) is preferably produced from oxidised polysilicon.

9. A micro check valve according to claim 8 wherein the diaphragm (18) at least in the moveable region of the diaphragm (18) has a stiffening element (122) which is formed from a layer formed additionally to the diaphragm and preferably corresponds to a grid, a ring or a plate and the first end of the at least one spring arm (120) is indirectly connected to the diaphragm (18) by way of the stiffening element (122).

10. A micro check valve according to claim 8 or claim 9 wherein the at least one spring arm (120) is adapted to apply a force to the moveable region of the diaphragm (18), that acts in the direction of the substrate body (12).

11. A micro check valve according to one of the preceding claims wherein the thickness of the diaphragm (18) and/or the spring force of the at least one spring arm (120) and/or the area of the moveable part of the diaphragm (18) and/or the number of through openings (42) in the diaphragm (18) is selected so as to provide a predefined opening pressure and/or a predefined closing pressure and a predefined through-flow quantity.

12. A system comprising a plurality of micro check valves (10) according to one of claims 1 to 11, wherein the micro check valves (10) have a common substrate body (12).

13. A system according to claim 12 wherein the through openings (42) are arranged distributed in such a way to produce predefined spray directions and/or a predefined preferential spray direction of a fluid or aerosol passed through the through openings (42).

14. A method for the production of a micro check valve (10), in particular according to one of claims 1 to 11, including the steps: a) producing a first oxide layer (76) which in particular is round and a second oxide layer (74) which in particular is annular on the top side (16) of a substrate body (12) which has a top side (16) and an underside (14), b) depositing a layer on the top side (16) of the substrate body (12) to form a diaphragm (18) at least above the first oxide layer (76) and the second oxide layer (74), c) etching through openings (42) in the diaphragm (18) in the region above the second oxide layer (74), d) etching at least one passage (24) from the underside (14) of the substrate body (12) to the first oxide layer (76), and e) removing the oxide layers (74, 76).

15. A method according to claim 14 wherein before step b) a third oxide layer (80) is produced in the region between the first oxide layer (76) and the second oxide layer (74), or an oxide layer (95) is deposited in the region over the first oxide layer (76), the second oxide layer (74) and in the region (96) between the first oxide layer (76) and the second oxide layer (74) by a deposition process.

16. A method according to claim 15 wherein the produced third oxide layer (80) of the annular region is produced for a spacing (92) of a thickness less than the thickness of the first oxide layer (76) and the second oxide layer (74).

17. A method according to one of claims 14 to 16 wherein the diaphragm (18) is deposited with a layer thickness which is dependent on a predetermined minimum pressure difference for opening and closing of the micro check valve (10).

18. A method according to one of claims 14 to 17 wherein after step e) oxidation (90, 106) of the structure produced is carried out.

Description

[0049] Further configurations will be apparent from the embodiments by way of example described in greater detail with reference to the Figures.

[0050] FIG. 1 shows a section of a micro check valve according to a first embodiment,

[0051] FIG. 2 shows an enlarged view of a portion of FIG. 1,

[0052] FIG. 3 shows a plan view of the micro check valve of FIGS. 1 and 2,

[0053] FIG. 4 shows a perspective sectional view of the micro check valve of FIGS. 1 to 3,

[0054] FIGS. 5a to 5c show the top side of different micro check valves with different configurations of the through openings,

[0055] FIG. 6 shows a further embodiment of a check valve,

[0056] FIG. 7 shows the steps for production of a micro check valve according to an embodiment,

[0057] FIG. 8 shows an additional step to the steps shown in FIG. 7 for the production of a micro check valve according to a further embodiment,

[0058] FIG. 9 shows a plan view of a micro check valve produced with the steps shown in FIG. 7,

[0059] FIG. 10 shows a further embodiment for the production of a micro check valve,

[0060] FIG. 11 shows the steps for the production of spring arms and a stiffening element of a micro check valve, and

[0061] FIG. 12 shows a plan view of a micro check valve with spring arms and a stiffening element, which is produced with the steps shown in FIG. 11.

[0062] FIG. 1 shows a sectional view of a micro check valve 10 according to a first embodiment. It is possible to see here a substrate body 12 having an underside 14 and a top side 16. A layer, for example of nitride, which forms a diaphragm 18, has been deposited on the top side 16. The substrate body 12 has recesses so that a first chamber 20 and a second chamber 22 are formed by the recesses together with the diaphragm 18, between the diaphragm 18 and the substrate body 12.

[0063] In addition a passage 24 passes through the substrate 12. The region 26 illustrated by the circle is shown on an enlarged scale in FIG. 2. In a further embodiment which is not shown here there are a plurality of passages 24.

[0064] Accordingly FIG. 2 shows the substrate body 12 on which a diaphragm 18 was produced by deposition. The substrate body 12 has a round recess corresponding to a first trough 30 and together with the diaphragm 18 forming the first chamber 20. In addition the substrate body has an annular recess corresponding to a second trough 32. The second trough 32 is arranged to extend around the first trough 30 such that the second trough 32 surrounds the round recess or trough 30. The second trough 32 with the diaphragm 18 accordingly forms a second surrounding chamber 22. The round or annular configuration of the troughs 30, 32 respectively cannot be seen in the sectional view shown here but will be clear in following FIGS. 3 and 4.

[0065] Formed between the second trough 32 and the first trough 30 is a sealing bar 34 in the form of a bar portion extending from the substrate 12, which remains after production of the two recesses or troughs. The passage 24 extending from the underside 14 which is not shown here in relation to FIG. 1 to the top side 16 of the substrate body 12 ends in the first trough 30. If in accordance with the above-mentioned further embodiment (not shown) there are a plurality of passages 24 then all passages 24 extend from the underside 14 to the top side 16 of the substrate body 12 and end in the first trough 30.

[0066] In the region of the sealing bar 34 the diaphragm 18 and the substrate body 12 are spaced with a predefined spacing which is a few micro- or nanometers. The spacing at any event is small in comparison with the spacing of the diaphragm 18 relative to the substrate body 12 in the region of the troughs 30, 32.

[0067] In the region of the first trough 30 and in the region of the sealing bar 34 the diaphragm 18 is flexible and moveable in a direction 36 forming a normal or a normal vector to the surface of the substrate body 12. If a fluid or an aerosol flows in the direction 38 through the passage 24 to the diaphragm 18 it presses against the diaphragm 18 from the underside 40 thereof. The spacing of the diaphragm 18 relative to the substrate body 12 in the region of the sealing bar 34 increases so that a fluid or aerosol can flow from the chamber 20 into the chamber 22 and can flow out through through openings 42 arranged in the region of the diaphragm 18 above the second trough 32.

[0068] If in contrast a fluid or an aerosol presses against the top side 44 of the diaphragm 18 then the diaphragm 18 is pressed against the substrate body 12 in the region of the sealing bar 34 so that the communication between the chambers 20 and 22 is closed and thus a return flow or backflow is prevented or at least reduced.

[0069] FIG. 3 shows a plan view of the micro check valve 10 of FIGS. 1 and 2. In this embodiment by way of example there are four through openings 42. The embodiment described with reference to FIGS. 1 to 3 however can also have a different number of through openings in further embodiments. The line 46 in this case shows the section line, along which the section in FIG. 1 is shown. The region of the diaphragm 18, that is over the second trough 32, is represented by the broken lines 48 and 50. The region of the diaphragm 18 above the first trough 30 is represented by the broken line 52 and thus the region of the diaphragm 18, that is above the sealing bar 34, is represented by the broken lines 50 and 52.

[0070] The broken line 54 shows the region of the diaphragm 18, that is above the passage 24. The diaphragm 18 is moveable in the normal direction relative to the plane of the drawing at least within the broken line 48 which can be referred to as the outside circle diameter of the second trough 32 and thus the starting region of an outer trough edge 47 while the diaphragm 18 is fixedly or immovably connected to the substrate body 12 outside the broken line 48, that is to say in the region of the outer trough edge 47. In addition the section in FIG. 1 is shown as a perspective view in FIG. 4.

[0071] FIG. 4 accordingly again shows the substrate body 12 and the diaphragm 18. The same references as used in preceding FIGS. 1 to 3 correspond to the same features.

[0072] FIGS. 5a to 5c respectively show the top side 16 of a micro check valve 10, wherein the various embodiments have different numbers and shapes of the through openings 4.

[0073] FIG. 5a shows four round through openings 42 distributed uniformly above the second trough 32. FIG. 5b shows a multiplicity of round through openings 42 which are arranged uniformly on the diaphragm 18 in the region above the second trough 32 and FIG. 5c shows six oval through openings 42 arranged uniformly over the surface of the circular ring above the second trough 32.

[0074] The various arrangements, shapes and numbers of the through openings 42 make it possible to set a given preferential spray direction as well as control of the through-flow amount and a minimum pressure difference for opening or closing of the valve. Accordingly the micro check valve 10 can also be used directly as a spray head.

[0075] FIG. 6 shows an alternative configuration of the micro check valve 10 which is produced by an alternative production technology to the production technology used for the micro check valve 10 which was shown in FIGS. 1 to 4. The same references however correspond to the same features as shown in FIGS. 1 and 4.

[0076] FIG. 7 shows the steps for the production of a micro check valve 10 according to an embodiment of the method. In this case a substrate body 12 is produced in step 70. In step 72 a first oxide layer 76 which is preferably round and a second oxide layer 74 which is preferably annular are produced, preferably by a LOCOS process (Local Oxidation of Silicon). In step 78 a third oxide layer 80 is produced between the previously produced first oxide layer 76 and second oxide layer 74, preferably being annular. The third oxide layer 80 is preferably also produced by a LOCOS process, but the third oxide layer is produced in a smaller thickness. Then in step 81 a layer 82, for example a silicon nitride, is deposited, forming a diaphragm 18 for the later check valve 10. Above the second oxide layer 74 through openings 42 are produced in the deposited layer 82 while in step 86 a passage 24 is etched through the substrate body 12 from an underside 14 of the substrate body 12 to the first oxide layer 76. The oxide layers 74, 76, 80 are then removed in step 88 by sacrificial layer etching.

[0077] FIG. 8 shows an additional step 90 to the steps shown in FIG. 7, by which, in a further embodiment, a further oxide layer 91 is produced over the structure of the micro check valve, in particular in the interior thereof. For that purpose, after step 88 in which the oxide layers are removed, the substrate is oxidised afresh. In that way the spacing 92 between the diaphragm and the sealing bar 34, which can also be referred to as the gap, is reduced to achieve a better closing action.

[0078] FIG. 9 shows a plan view of the steps illustrated in FIG. 7 and optionally the micro check valve 10 produced with the step described with reference to FIG. 8.

[0079] FIG. 10 shows an alternative method for the production of the micro check valve 10. Firstly a substrate body 12 is again produced in a step 70. In step 72 a first oxide layer 76 which is preferably round and a second oxide layer 74 which is preferably annular are produced. The first oxide layer 70 and the second oxide layer 74 are preferably produced by a LOCOS process. In step 94 however an oxide layer 95 is now deposited in the region over the first oxide layer 76, the second oxide layer 74 and the interposed region 96, by a deposition process, for example an LPCDV process. Thereupon steps 98, 100, 102, 104 and 106 are carried out like steps 81, 84, 86, 88 and 90.

[0080] Accordingly therefore in step 98 a layer 82, for example a silicon nitride, is deposited, forming the diaphragm 18 for the later check valve 10. Then in step 100 through openings 42 are produced in the deposited layer 82 above the second oxide layer 74 while in step 102 a passage 24 is etched through the substrate body 12 from an underside 14 of the substrate body 12 to the first oxide layer 76. The oxide layers 74, 76, 95 are then removed in step 104 by sacrificial layer etching. In that case now firstly the last-deposited oxide layer 95 is attacked so that removal of the remaining oxide layer can be effected substantially more quickly by virtue of the increased surface area for attacking the oxide layers. Step 104 is thus admittedly identical to step 88, but takes substantially less time for implementation thereof.

[0081] Step 106 corresponds to the optional additional step shown in FIG. 8 for producing an oxidised surface.

[0082] FIG. 11 shows modified steps of the production described with reference to FIG. 7 for producing the spring arms and the stiffening element. In accordance therewith firstly steps 70, 72, 78, 81 and 84 are carried out as described with reference to FIG. 7. Thereupon however in a step 108 an oxide layer 110 is produced at least in an annular region which is partially above the later moveable region of the diaphragm 18. Then in step 112 a polysilicon structure 114 is produced, being of the shape of the later spring arms and the stiffening element. Thereupon in step 116 the passage 24 is etched and in step 118 the oxide layers 74, 76, 80 and 110 are removed.

[0083] FIG. 12 shows a plan view of the micro check valve which is produced involving the steps described with reference to FIG. 11. Here now the spring arms 120 and the stiffening element 122 are produced in comparison with FIG. 9.

LIST OF REFERENCES

[0084] 10 micro check valve [0085] 12 substrate body [0086] 14 underside of the substrate body [0087] 16 top side of the substrate body [0088] 18 diaphragm [0089] 20 first chamber [0090] 22 second chamber [0091] 24 passage [0092] 26 region [0093] 30 first trough [0094] 32 second trough [0095] 34 sealing bar [0096] 36, 38 directions [0097] 40 underside of the diaphragm [0098] 42 through openings [0099] 44 top side of the diaphragm [0100] 46 section line [0101] 47 outer trough edge [0102] 48-54 broken lines [0103] 70, 72, 78 steps in the method [0104] 74 second oxide layer [0105] 76 first oxide layer [0106] 80 third oxide layer [0107] 81 step in the method [0108] 82 deposited layer [0109] 86, 88, 90 steps in the method [0110] 91 further oxide layer [0111] 92 spacing or gap [0112] 94 step [0113] 95 oxide layer [0114] 96 region [0115] 98-108 steps [0116] 110 oxide layer [0117] 112 step [0118] 114 polysilicon structure [0119] 116, 118 steps [0120] 120 spring arms [0121] 122 stiffening element