SENSOR BODY HAVING A MEASURING ELEMENT AND METHOD FOR MANUFACTURING FOR A SENSOR BODY

Abstract

A sensor body for receiving a pressurized fluid or for absorbing a force, having a membrane and at least one strain sensitive measuring element disposed on the membrane, comprising, a semiconductor substrate and at least one piezo resistive resistance track, wherein the resistance track is formed in the semiconductor substrate by means of doping. According to the invention, the measuring element is connected to the membrane by means of a lead-free glass solder and the measuring element is arranged, at least in sections, sunk into the glass solder. A measuring element, a pressure sensor, a force measuring device, a method for manufacturing a sensor body and the use of a measuring element is also provided.

Claims

1. A method for manufacturing a sensor body, the method comprising: A. providing a sensor body, at least one measuring element and either a lead-free glass solder paste or at least one lead-free molded glass part, wherein the lead-free glass solder paste comprises glass particles and volatile, organic components; B. applying the lead-free glass solder paste on at least one surface portion of a membrane of the sensor body or placing the lead-free molded glass part on the at least one surface portion of the membrane of the sensor body; C. applying the at least one measuring element to the lead-free glass solder paste or to the lead-free molded glass part; D. heating the sensor body to a temperature and storing the sensor body at the temperature for a storage period, so that either the volatile, organic components of the lead-free glass solder paste vaporize and the glass particles melt to form a lead-free glass solder into which the at least one measuring element sinks without an application of force or the lead-free molded glass part melts to create a lead-free glass solder into which the at least one measuring element sinks without an application of force; and E. after step D, cooling the sensor body so that the lead-free glass solder solidifies thereby connecting the at least one measuring element to the membrane of the sensor body.

2. The method according to claim 1, wherein the at least one measuring element has a semiconductor substrate, the semiconductor substrate having an upper side and a lower side, wherein, in a plan view, a surface of the upper side fully projects beyond a surface of the lower side over an entire edge of the surface of the lower side such that the lower side has a smaller area than the upper side, wherein side faces of the semiconductor substrate continuously taper from the upper side in a direction of the lower side, at least in sections, such that the semiconductor substrate has a tapered configuration, wherein in step C, the lower side of the semiconductor substrate of the at least one measuring element is applied to the lead-free glass solder paste or to the lead-free molded glass part, and wherein in step D, the at least one measuring element sinks into the lead-free glass solder, starting from the lower side of the semiconductor substrate, without application of force due to the tapered configuration of the semiconductor substrate.

3. The method according to claim 1, wherein the temperature is between 300° C. and 600° C.

4. A method for manufacturing a sensor body, the method comprising: A. providing a sensor body, at least one measuring element and either a lead-free glass solder paste or at least one lead-free glass part, wherein the lead-free glass solder paste comprises glass particles and volatile, organic components; B. applying the lead-free glass solder paste on at least one surface portion of a membrane of the sensor body or placing the lead-free molded glass part on the at least one surface portion of the membrane of the sensor body; C. heating the sensor body to a temperature and storing the sensor body at the temperature for a storage period, so that the volatile components of the lead-free glass solder paste vaporize and the glass particles melt to form a lead-free glass solder or the lead-free molded glass part melts to create a lead-free glass solder and adheres to the membrane; D. applying the at least one measuring element to the lead-free glass solder so that the measuring element sinks into the lead-free glass solder without application of force; and E. after step D, cooling the sensor body so that the lead-free glass solder solidifies thereby connecting the at least one measuring element to the membrane of the sensor body.

5. The method according to claim 4, wherein the at least one measuring element has a semiconductor substrate, the semiconductor substrate having an upper side and a lower side, wherein, in a plan view, a surface of the upper side fully projects beyond a surface of the lower side over an entire edge of the surface of the lower side such that the lower side has a smaller area than the upper side, wherein side faces of the semiconductor substrate continuously taper from the upper side in a direction of the lower side, at least in sections, such that the semiconductor substrate has a tapered configuration, wherein in step D, the lower side of the semiconductor substrate of the at least one measuring element is applied to the lead-free glass solder so that the at least one measuring element sinks into the lead-free glass solder, starting from the lower side of the semiconductor substrate, without application of force due to the tapered configuration of the semiconductor substrate.

6. The method according to claim 5, wherein the temperature is between 300° C. and 600° C.

7. A method for manufacturing a sensor body, the method comprising: A. providing a sensor body, at least one measuring element and either a lead-free glass solder paste or at least one lead-free glass part, wherein the lead-free glass solder paste comprises glass particles and volatile, organic components; B. applying the lead-free glass solder paste on at least one surface portion of a membrane of the sensor body or placing the lead-free molded glass part on the at least one surface portion of the membrane of the sensor body; C. heating the sensor body to a temperature and storing the sensor body at the temperature for a storage period, so that the volatile components of the lead-free glass solder paste vaporize and the glass particles melt to form a lead-free glass solder or the lead-free molded glass part melts to create a lead-free glass solder and adheres to the membrane; D. after step C, cooling the sensor body so that the lead-free glass solder solidifies; E. after step D, applying the at least one measuring element to the lead-free glass solder; F. after step E, re-heating the sensor body to reliquify the lead-free glass solder so that the measuring element sinks into the lead-free glass solder without application of force; and G. after step F, cooling the sensor body so that the lead-free glass solder re-solidifies thereby connecting the at least one measuring element to the membrane of the sensor body.

8. The method according to claim 7, wherein the at least one measuring element has a semiconductor substrate, the semiconductor substrate having an upper side and a lower side, wherein, in a plan view, a surface of the upper side fully projects beyond a surface of the lower side over an entire edge of the surface of the lower side such that the lower side has a smaller area than the upper side, wherein side faces of the semiconductor substrate continuously taper from the upper side in a direction of the lower side, at least in sections, such that the semiconductor substrate has a tapered configuration, wherein in step E, the lower side of the semiconductor substrate of the at least one measuring element is applied to the lead-free glass solder so that the at least one measuring element sinks into the lead-free glass solder, starting from the lower side of the semiconductor substrate, without application of force due to the tapered configuration of the semiconductor substrate.

9. The method according to claim 8, wherein the temperature is between 300° C. and 600° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0056] FIG. 1 schematically shows a sectional view of a sensor body,

[0057] FIG. 2 schematically shows a perspective view of the sensor body according to FIG. 1,

[0058] FIG. 3 schematically shows a perspective view of a measuring element with a view of an upper side of a semiconductor substrate of the measuring element,

[0059] FIG. 4 schematically shows a perspective view of the measuring element according to FIG. 3 with a view of a lower side of the semiconductor substrate of the measuring element,

[0060] FIG. 5 schematically shows a semitransparent plan view of a rectangular measuring element with a view of an upper side of a semiconductor substrate of the measuring element,

[0061] FIG. 6 schematically shows a semitransparent plan view of a hexagonal measuring element with a view of an upper side of a semiconductor substrate of the measuring element,

[0062] FIG. 7 schematically shows a plan view of the rectangular measuring element according to FIG. 4 with a view of a lower side of the semiconductor substrate of the measuring element,

[0063] FIG. 8 schematically shows a plan view of the hexagonal measuring element according to FIG. 6 with a view of a lower side of the semiconductor substrate of the measuring element,

[0064] FIG. 9 schematically shows a sectional view of a section of a sensor body,

[0065] FIG. 10 schematically shows a sectional view of a semiconductor substrate of a measuring element in an edge region,

[0066] FIG. 11 schematically shows a sectional view of a semiconductor substrate of a measuring element in an edge region,

[0067] FIG. 12 schematically shows a sectional view of a semiconductor substrate of a measuring element in an edge region,

[0068] FIG. 13 schematically shows a sectional view of a semiconductor substrate of a measuring element in an edge region,

[0069] FIG. 14 schematically shows a plan view of a section of a measuring element with a view of an upper side of a semiconductor substrate of the measuring element,

[0070] FIG. 15 schematically shows a plan view of a section of a measuring element with a view of an upper side of a semiconductor substrate of the measuring element,

[0071] FIG. 16 schematically shows a plan view of a section of a measuring element with a view of an upper side of a semiconductor substrate of the measuring element,

[0072] FIG. 17 schematically shows a sectional view of a section of a pressure sensor,

[0073] FIG. 18 schematically shows cross-sectional views of a section of a sensor body during various steps of a method for the manufacture thereof,

[0074] FIG. 19 schematically shows cross-sectional views of a section of a sensor body during various steps of a method for the manufacture thereof,

[0075] FIG. 20 schematically shows cross-sectional views of a section of a sensor body during various steps of a method for the manufacture thereof,

[0076] FIG. 21 schematically shows cross-sectional views of a section of a sensor body during various steps of a method for the manufacture thereof,

[0077] FIG. 22 schematically shows a sectional view of a sensor body in an unloaded state,

[0078] FIG. 23 schematically shows sectional views of the sensor body according to FIG. 22 in a loaded state,

[0079] FIG. 24 schematically shows an exemplary embodiment of a force measuring device and

[0080] FIG. 25 schematically shows another exemplary embodiment of a force measuring device.

DETAILED DESCRIPTION

[0081] FIG. 1 shows a sectional view of a possible embodiment of a sensor body 120 for a pressure sensor 100 shown in FIG. 17 or for force measuring devices 190 shown in FIGS. 24 and 25. FIG. 2 shows a perspective view of the sensor body 120 according to FIG. 1.

[0082] The sensor body 120 is designed to receive a pressurized fluid or to absorb forces.

[0083] In the illustrated embodiment, the sensor body 120 has a hat shape in which the sensor body 120 comprises an upper side surface, which is formed by a membrane 121. In this case, the membrane 121 extends in particular over the entire width, in the exemplary embodiment shown over an entire diameter d, of the upper side surface. The diameter d is, for example, 2.5 mm to 15 mm.

[0084] For example, the sensor body 120 is made of an iron alloy, in particular of a stainless steel. Alternatively, the sensor body 120 is formed from a non-ferrous metal alloy, wherein the non-ferrous metal alloy is in particular coated with a metallic adhesion-promoting layer, or the sensor body 120 is formed of a ceramic.

[0085] A lateral surface, extending at least substantially perpendicular to the cover surface in an illustrated unloaded state of the sensor body 120, terminates in a peripheral flange-like structure which in the unloaded state of the sensor body 120 projects at least substantially perpendicularly at an end of the lateral surface facing away from the cover surface. The flange-like structure is thereby formed to mount the sensor body 120 within the pressure sensor 100, or to the force measuring device 190.

[0086] The sensor body 120 comprises at least one strain sensitive measuring element 130 disposed on an upper side of the membrane 121. The measuring element 130 is connected to the membrane 121 by means of a lead-free glass solder 150 and the measuring element 130 is arranged, at least in sections, sunk into the glass solder 150. That is, the measuring element 130 is at least partially sunk into the glass solder 150; at least one volume section of the measuring element 130 is sunk into the glass solder 150.

[0087] FIGS. 3 and 4 show perspective views of a possible exemplary embodiment of a measuring element 130 with a view of an upper side 134 and a lower side 135 of a semiconductor substrate 131 of the measuring element 130.

[0088] In addition to the semiconductor substrate 131, which is in particular a silicon crystal, the measuring element 130 comprises at least one piezoresistive resistance track 132, which is formed in the semiconductor substrate 131 by means of doping. The resistance track 132 has contact surfaces 133 at its ends to provide electrical contact.

[0089] The at least one resistance track 132 is in particular formed by a structured p-type doping in the semiconductor substrate 131 and lies at least essentially in a {110} crystal plane of the silicon crystal and runs at least essentially along a <110> crystal direction or a <111> crystal direction. Alternatively, the at least one resistance track 132 is formed by a structured n-type doping in the semiconductor substrate 131 and lies at least essentially in a {100} crystal plane or a {110} crystal plane of the silicon crystal and runs at least essentially along a <100> crystal direction.

[0090] The semiconductor substrate 131 has, for example, a thickness of 0.005 mm to 0.1 mm and/or a width of 0.1 mm to 2.8 mm and/or a length of 0.2 mm to 3.8 mm. For example, the upper side 134 and the lower side 135 are at least substantially parallel to one another and are at least substantially rectangular in shape.

[0091] In order to enable or simplify sinking of the measuring element 130 into the lead-free glass solder 150, side faces 136 of the semiconductor substrate 131 are continuously tapered, at least in sections, from the upper side 134 towards the lower side 135. This means that in a plan view, a surface of the upper side 134 extends over the edge of the entire circumference of a surface of the lower side 135, so that the lower side 135 is a smaller area than the upper side 134. The semiconductor substrate 130 thus tapers from its upper side 134 to its lower side 135.

[0092] FIG. 5 shows a semitransparent plan view of a possible embodiment of a rectangular measuring element 130 with a view of the upper side 134 of the semiconductor substrate 131 of the measuring element 130, which illustrates that in the plan view, the surface of the upper side 134 fully projects beyond the surface of the lower side 135 over its entire edge, so that the lower side 135 is a smaller area than the upper side 134 and the semiconductor substrate 131 tapers from its upper side 134 toward its lower side 135.

[0093] FIG. 6 shows a semitransparent plan view of a possible embodiment of a hexagonal measuring element 130 with a view of the upper side of the semiconductor substrate 131 of the measuring element 130, which demonstrates that in the plan view, the surface of the upper side 134 fully projects beyond the surface of the lower side 135 over its entire edge, so that the lower side 135 is a smaller area than the upper side 134 and the semiconductor substrate 131 tapers from its upper side 134 toward its lower side 135.

[0094] FIG. 7 shows a plan view of the rectangular measuring element 130 according to FIG. 5 with a view of the lower side 135 of the semiconductor substrate 131 of the measuring element 130.

[0095] FIG. 8 schematically shows a plan view of the hexagonal measuring element 130 according to FIG. 6 with a view of the lower side 135 of the semiconductor substrate 131 of the measuring element 130.

[0096] FIG. 9 shows a sectional view of a detail of a possible embodiment of a sensor body 120. In this embodiment, the measuring element 130, for example, is arranged such in the glass solder 150 that a glass solder film 151 having a thickness of 0.001 mm to 0.1 mm is formed between the lower side 135 of the measuring element 130 and a surface of the membrane 121, and/or the upper side 134 of the measuring element 130 protrudes from the glass solder 150 by 0 percent to 95 percent of the thickness of the measuring element 130. It is also possible for the measuring element 130 to be arranged at least substantially flush with a surface of the glass solder 150 in the latter.

[0097] FIG. 10 shows a sectional view of a possible embodiment of a semiconductor substrate 131 of a measuring element 130 in an edge region.

[0098] In this exemplary embodiment, side faces 136 of the semiconductor substrate 131 are continuously tapered from the upper side 134 to the lower side 135 of the semiconductor substrate 131.

[0099] In this case, an average angle 137 of a side face cross section to a surface normal 138 of the upper side 134 is more than 0°, in particular at least 5°, in particular at least 15°.

[0100] The side faces 136 in particular have a flat surface, so that the semiconductor substrate 131 has at least substantially the shape of a truncated pyramid, wherein the upper side 134 forms a base of the truncated pyramid and the lower side 135 forms a cover surface of the truncated pyramid.

[0101] Such a shape of the side faces 136 is manufactured, for example, in a sawing process or in a laser cutting process.

[0102] FIG. 11 shows a sectional view of another possible embodiment of a semiconductor substrate 131 of a measuring element 130 in an edge region.

[0103] In this exemplary embodiment, the side faces 136 of the semiconductor substrate 131 have a concave surface, at least in sections.

[0104] Such a shape of the side surfaces 136 is manufactured, for example, in an etching process or in a laser cutting process.

[0105] In this case, an average angle 137 of an average side face cross section to a surface normal 138 of the upper side 134 is more than 0°, in particular at least 5°, in particular at least 15°.

[0106] FIG. 12 shows a sectional view of a further possible exemplary embodiment of a semiconductor substrate 131 of a measuring element 130 in an edge region.

[0107] In this exemplary embodiment, the side faces 136 of the semiconductor substrate 131 have a wavy surface, at least in sections.

[0108] Such a shape of the side faces 136 is, for example, manufactured by machining the semiconductor substrate 131 using a laser, wherein the machining is carried out in particular in several steps with respectively decreasing beam waists of the laser.

[0109] In this case, an average angle 137 of an average side face cross section to a surface normal 138 of the upper side 134 is more than 0°, in particular at least 5°, in particular at least 15°.

[0110] FIG. 13 shows a sectional illustration of a further possible exemplary embodiment of a semiconductor substrate 131 of a measuring element 130 in an edge region.

[0111] In contrast to the exemplary embodiment shown in FIG. 10, the side faces 136 of the semiconductor substrate 131 are tapered continuously only in sections from the upper side 134 toward the lower side 135.

[0112] FIG. 14 depicts a plan view of a section of a possible embodiment of a measuring element 130 with a view of the upper side 134 of the semiconductor substrate 131 of the measuring element 130.

[0113] The measuring element 130 comprises a strip-shaped resistance track 132, which comprises contact surfaces 133 at its ends.

[0114] In this case, the resistance track 132 is formed by a structured p-type doping in the semiconductor substrate 131 and lies at least essentially in a {110} crystal plane of the silicon crystal, wherein its running direction 160, i.e., a measuring direction, extends at least essentially along a <110> crystal direction or a <111> crystal direction. Alternatively, the at least one resistance track 132 is formed by a structured n-type doping in the semiconductor substrate 131 and lies at least essentially in a {100} crystal plane or a {110} crystal plane of the silicon crystal, wherein the running direction 160 thereof, i.e., a measuring direction, extends at least essentially along a <100> crystal direction.

[0115] FIG. 15 shows a plan view of a detail of a possible further embodiment of a measuring element 130, with a view of the upper surface 134 of the semiconductor substrate 131 of the measuring element 130.

[0116] In contrast to the exemplary embodiment shown in FIG. 14, the resistance track 132 has a meandering shape. The resistance track in a meandering shape enables that a long strain of the resistance track 132 in the direction of the strain load is achieved even on a semiconductor substrate 131 with limited dimensions, while at the same time the strain of the resistance track 132 in the transverse direction being small. As a result, the achievable measurement signal can be enhanced, and the measurement accuracy can consequently be improved.

[0117] FIG. 16 shows a plan view of a section of a possible further exemplary embodiment of a measuring element 130 with a view of the upper side 134 of the semiconductor substrate 131 of the measuring element 130.

[0118] In contrast to the exemplary embodiment shown in FIG. 14, the measuring element 130 comprises two resistance tracks 132, wherein the resistance tracks 132 in particular are arranged parallel to one another, and contact surfaces 133 of the resistance tracks 132 are electrically insulated from one another.

[0119] FIG. 17 shows a sectional illustration of a section of a possible exemplary embodiment of a pressure sensor 100.

[0120] The pressure sensor 100 is configured to convert a pressure into an electrical signal, and includes a sensor body 120, a terminal body 170, a housing 110, an evaluation electronics 140 and a transmission 180.

[0121] Here, the terminal body 170 is sealingly connected to the sensor body 120 and sealingly connectable to a fluid source. By means of the terminal body 170, a fluid can be introduced in the sensor body 120.

[0122] The evaluation electronics 140 is electrically connected to the at least one resistance track 132 and adapted to convert a change in resistance of the resistive track 132 to an electrical measurement signal.

[0123] The housing 110 is connected to the terminal body 170, so that the membrane 121, the measuring element 130 and the evaluation electronics 140 are at least in sections, that is, at least partially, enclosed by the housing 110.

[0124] The transmission 180 is connected to the evaluation electronics 140 in such a way that it converts the electrical measurement signal to an electrical output signal and either makes it available by means of contacts that are accessible from outside the housing 110 or emits it as a radio signal.

[0125] FIG. 18 shows sectional views of a section of a sensor body 120 during various steps A through E of a possible embodiment of a method for manufacturing the same.

[0126] In the method, in a step a sensor body 120, at least one measuring element 130 and a lead-free glass solder paste 152 are provided. The glass solder paste 152 comprises glass particles 153 and volatile, in particular organic, components 154.

[0127] In a step B, the glass solder paste 152 is applied to a surface portion 123 of the membrane 121 of the sensor body 120.

[0128] In a step C, the measuring element 130 is applied to the glass solder paste 152 in such a way that its lower side 135 is placed on the glass solder paste 152 or is pressed slightly into it.

[0129] Subsequently, in a step D, the sensor body 120 is heated to at least a temperature and the sensor body 120 is stored at this temperature for a storage period so that the volatile components 154 of the glass solder paste 152 are vaporized, the glass particles 153 melt, and the measuring element 130 sinks into a glass solder 150 thus created. For example, the temperature to which the sensor body 120 is heated is between 300 degrees Celsius and 600 degrees Celsius. The sensor body 120 is stored at this temperature, for example, for a storage period between 30 seconds and 5 hours. Suitable temperatures and storage times depend on the selected glass solder make and its specifications. In particular, the heating and storage of the sensor body 120 can take place over at least two stages, wherein at a first lower temperature stage initially the volatile components 154 of the glass solder paste 152 are vaporized and then, at a second higher temperature stage, the glass particles 153 are re-melted to a glass solder 150.

[0130] In a step E, not shown, this is followed by a cooling of the sensor body 120 so that the glass solder 150 solidifies.

[0131] FIG. 19 shows sectional views of a section of a sensor body 120 during various steps A through D of a further possible embodiment of a method for its manufacture.

[0132] In contrast to the process shown in FIG. 18, a step B1 is carried out between step B and step C, in which the sensor body 120 is heated to a temperature and the sensor body 120 is stored at this temperature for a storage period, so that the volatile components 154 of the glass solder paste 152 already vaporize and the glass particles 153 melt before the measuring element 130 is applied on the glass solder paste 152. For example, the temperature to which the sensor body 120 is heated is between 300 degrees Celsius and 600 degrees Celsius. The sensor body 120 is stored at this temperature, for example, for a storage period between 30 seconds and 5 hours. Suitable temperatures and storage periods depend on the selected glass solder make and its specifications. In particular, the heating and storage of the sensor body 120 can take place over at least two stages, wherein initially the volatile components 154 of the glass solder paste 152 are vaporized at a first lower temperature stage and then, at a second higher temperature stage, the glass particles 153 are re-melted to a glass solder 150.

[0133] The measuring element 130 is applied to the heated glass solder paste 152 in step C, so that the former sinks in step D. As a result, the measuring element 130 is only exposed to a small amount of heat.

[0134] As a result, in a step E, not shown, the sensor body 120 is cooled so that the glass solder 150 solidifies.

[0135] FIG. 20 shows sectional views of a section of a sensor body 120 during various steps A through E of a further possible embodiment of a method for the manufacture thereof.

[0136] In contrast to the exemplary embodiment of the method shown in FIG. 18, a molded glass part 155 is used instead of the glass solder paste 152.

[0137] Here, in a step A, a sensor body 120, at least one measuring element 130 and at least one lead-free molded glass part 155 are provided, before in a step B the molded glass part 155 is placed on a surface portion 123 of the membrane 121 of the sensor body 120.

[0138] In a step C, the measuring element 130 is applied on the molded glass part 155, before in a step D the sensor body 120 is heated to a temperature and the sensor body 120 is stored at this temperature for a storage period, so that the molded glass part 155 melts and the measuring element 130 sinks into a glass solder 150 thus created. For example, the temperature to which the sensor body 120 is heated is between 300 degrees Celsius and 600 degrees Celsius. The sensor body 120 is stored at this temperature, for example, for a storage period between 30 seconds and 5 hours. Suitable temperatures and storage times depend on the selected molded glass part make and its specifications.

[0139] Then, in a step E, not shown, the sensor body 120 is cooled so that the glass solder 150 solidifies.

[0140] FIG. 21 shows sectional views of a section of a sensor body 120 during various steps A through D of a further possible embodiment of a method for its manufacture.

[0141] In contrast to the process illustrated in FIG. 20, a step B1 is performed between step B and step C in which the sensor body 120 is heated to a temperature and the sensor body 120 is stored at this temperature for a storage period, so that the molded glass part 155 melts to a glass solder 150 and adheres to the membrane 121, before the measuring element 130 is applied on the glass solder 150. For example, the temperature to which the sensor body 120 is heated is between 300 degrees Celsius and 600 degrees Celsius. The sensor body 120 is stored at this temperature, for example, for a storage period between 30 seconds and 5 hours. Suitable temperatures and storage times depend on the selected molded glass part make and its specifications.

[0142] The measuring element 130 is applied to the heated glass solder paste 152 in step C, so that it sinks in a step D. As a result, the measuring element 130 is only exposed to a small amount of heat.

[0143] In a not-shown step E, the sensor body 120 is cooled so that the glass solder 150 solidifies.

[0144] FIG. 22 shows a sectional view of a possible embodiment of a sensor body 120 in an unloaded state. FIG. 23 shows the sensor body 120 in a loaded, i.e., in a pressurized state, or in a state in which forces are introduced in the sensor body.

[0145] It can be seen here that in a loaded state, the membrane 121 bulges in a central region 124 in such a way that on its side facing the measuring element 130, surface portions with strong positive strain (stretching) 126 of the surface are formed and surface portions with strong negative strain (compression) 127 of the surface are formed. The outer region 125 of the membrane 121 adjoining the central region 124 experiences essentially no deformation. The position of surface portions 123 with a strong strain 126 or with strong compression 127 of the surface depends on the particular shape of the membrane 121.

[0146] To achieve a particularly reliable and accurate measurement of the shape change of the membrane 121, it is provided in one possible embodiment of the sensor body 120 that in the central region 124, two resistance tracks 132 are disposed in such a manner in a surface portion with a strong positive strain (stretching) 126 of the surface that the running direction 160 extends in the direction of the possible stretch. The resistance tracks 132 can be divided between two measuring elements 130 or arranged on a common measuring element 130. Two further resistance tracks 132 are arranged in a surface portion with strong negative strain (compression) 127 in such a way that their running direction 160 extends in the direction of the possible compression 127. These resistance tracks 132 can also be divided between two measuring elements 130 or arranged on a common measuring element 130. The four resistance tracks 132 are connected to a Wheatstone measuring bridge 139 in such a way that the two resistance tracks, which are disposed in a region with the same strain direction, in each case lie diagonally opposite in the circuit diagram of the measuring bridge.

[0147] Here, a large voltage signal is generated in a particularly advantageous manner, which results from the fact that when deformed, the electrical resistance of the resistance tracks 132 increases in areas with strong stretching 126 and the electrical resistance of the resistance tracks 132 decreases in areas with strong compression 127.

[0148] In a further possible embodiment of the sensor body 120, it is provided that a total of four resistance tracks 132 are disposed on the membrane 121 and are connected to a Wheatstone measuring bridge 139, wherein at least one resistance track 132 is arranged in the central region 124 of the membrane 121 in a surface portion with strong stretching 126 or severe compression 127, while the remaining resistance tracks 132 are arranged in the edge region 125.

[0149] Here, a very precise voltage signal is generated in a particularly advantageous manner, which results from the fact that the at least one resistance track 132 disposed in the central region 124 is deformed upon pressurization of the sensor body 120 and changes its resistance, while the other resistance tracks 132 are not substantially deformed and thus show no change in resistance.

[0150] The voltage signal can be amplified by the fact that the resistance tracks 132 are each formed by the structured p-type doping in the semiconductor substrate 131 and at least essentially lie in the {110} crystal plane of the silicon crystal, wherein their direction of extension 160 runs at least essentially along a <110> crystal direction or the <111> crystal direction, or alternatively, the resistance tracks 132 are each formed by the structured n-type doping in the semiconductor substrate 131 and at least essentially lie in the {100} crystal plane or the {110} crystal plane of the silicon crystal, wherein their direction of extension 160 runs at least substantially along the <100> crystal direction.

[0151] In a further possible configuration of the sensor body 120, four resistance tracks 132 are formed in the semiconductor substrate 131 of a single measuring element 130, wherein the resistance tracks 132 are formed by a structured p-type doping in the semiconductor substrate 131 and at least essentially lie in a {110} crystal plane of the silicon crystal. Two of the four resistance tracks 132 form a first pair, which is oriented at least substantially along a <110> crystal direction or a <111> crystal direction or extends in one of these crystal directions. The remaining two resistance tracks 132 form a second pair, which is aligned substantially perpendicular to the alignment of the first pair of resistance tracks. Thus, the first pair of resistance tracks 132 runs in a direction in which the resistance, as already described in a previous section, depends essentially only on strain in the direction of extension of the tracks, while the second pair of resistance tracks 132 runs in a transverse direction thereto, in which the resistance is essentially independent of the strain in this transverse direction. The four resistance tracks 132 can in particular be interconnected to form a Wheatstone bridge circuit in such a way that the resistance tracks 132 of the first pair and the resistance tracks 132 of the second pair are each diagonally opposite in the circuit diagram of the bridge circuit. This has the advantage that a measuring element 130 with such a measuring bridge is essentially only sensitive to strain, that is to say stretching/compression, along the orientation of the first pair of resistance tracks 132, and a very precise measuring signal can be tapped in relation thereto. The connection to a measuring bridge can be formed within the semiconductor substrate 131 or can be manufactured outside the measuring element 130 by contacting the individual resistance tracks 132. A sensor body 120 can be manufactured particularly simply and inexpensively with such a measuring element 130, since only one measuring element 130 has to be applied. In addition, this can be arranged anywhere on the membrane. The sensor body 120 can be manufactured particularly advantageously by arranging such a measuring element 130 centrally in a central region 124 on the membrane 121, since essentially no asymmetries are created in the loading of the membrane 121.

[0152] FIG. 24 shows a possible embodiment of a force measuring device 190 for converting a force F to an electric signal.

[0153] The force measuring device 190 comprises two sensor bodies 120, two storage areas 191, a load introduction area 192, an evaluation electronics 140, a transmission 180 and two deformation sections 193, in which in each case one sensor body 120 is disposed.

[0154] In this case, the deformation sections 193 are connected with the respective sensor body 120, and the force F can be introduced in the sensor body 120 by means of said deformation sections 193.

[0155] The evaluation electronics 140 is in each case electrically connected to the at least one resistance track 132, not shown in detail, of the respective sensor body 120 and adapted to convert a change in resistance of the resistance tracks 132 to an electrical measurement signal.

[0156] The transmission 180 is connected such with the evaluation electronics 140 that it converts the electrical measurement signal to an electrical output signal and either makes it available by means of contacts or emits it as a radio signal.

[0157] FIG. 25 shows a further possible exemplary embodiment of a force measuring device 190 for converting a force F to an electrical signal.

[0158] In contrast to the embodiment illustrated in FIG. 24, the force measuring device 190 comprises a storage area 191, a load introduction area 192, an evaluation electronics 140, a transmission 180 and a deformation section 193, in which two sensor bodies 120 are arranged.

[0159] The deformation section 193 is connected to the sensor bodies 120 and the force F can be introduced in the sensor bodies 120 by means of the deformation section 193.

[0160] Between the sensor bodies 120, a slot-shaped recess 194 is formed in the deformation section 193, so that with an introduction of the force F, a resulting deformation of the deformation section 193 is focused in the area of the sensor bodies 120 and thus, the deformation is very reliable detected. The recess 194 can also have any other desired shape.

[0161] The invention is not restricted to the preceding, detailed exemplary embodiments. It can be modified within the scope of the following claims.

[0162] Individual aspects from the dependent claims can also be combined with one another.

[0163] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.