Micromechanical component with diffusion stop channel

Abstract

Method for producing a micromechanical component (1) with a substrate (3) and with a cap (7) connected to the substrate (3) and enclosing a first cavity (5) with the substrate (3), wherein a first pressure prevails in the first cavity (5) and a first gas mixture with a first chemical composition is enclosed, wherein the cap (7) encloses a second cavity with the substrate (3), wherein a second pressure prevails in the second cavity and a second gas mixture with a second chemical composition is enclosed, wherein -- in a first process step (101) an access opening (11) connecting the first cavern (5) with a surrounding (9) of the micromechanical component (1) is formed in the substrate (3) or in the cap (7), wherein -- in a second process step (102) the first pressure and / or the first chemical composition is set in the first cavern (5), wherein -- in a third process step (103) the access opening (11) is closed by introducing energy or heat into an absorbing part of the substrate (3) or the cap (7) using a laser, characterized in that -- in a fourth process step (104) a recess (1501) arranged essentially between the first cavern (5) and the second cavern is formed for the purpose of diverting at least one first particle type (A) of the first gas mixture and / or at least one second particle type (B) of the second gas mixture, wherein the recess (1501) forms a second access opening connected to the surroundings (9).

Description

State of the art

[0001] The invention relates to a method according to the preamble of claim 1.

[0002] Such a method is known from WO 2015 / 120939 A1. If a specific internal pressure is desired in a cavity of a micromechanical component, or if a gas mixture with a specific chemical composition is to be enclosed in the cavity, the internal pressure or chemical composition is often adjusted during the capping of the micromechanical component or during the bonding process between a substrate wafer and a cap wafer. During capping, for example, a cap is bonded to a substrate, whereby the cap and the substrate together enclose the cavity. By adjusting the atmosphere or the pressure and / or the chemical composition of the gas mixture present in the environment during capping, the desired internal pressure and / or chemical composition in the cavity can thus be set.

[0003] The method known from WO 2015 / 120939 A1 allows for the targeted adjustment of internal pressure in a cavity of a micromechanical component. In particular, this method makes it possible to produce a micromechanical component with a first cavity, in which a first pressure and a first chemical composition can be set that differ from a second pressure and a second chemical composition at the time of capping.

[0004] In the method for precisely controlling the internal pressure in a cavity of a micromechanical component according to WO 2015 / 120939 A1, a narrow access channel to the cavity is created in the cap or cap wafer, or in the substrate or sensor wafer. The cavity is then flooded with the desired gas and internal pressure via the access channel. Finally, the area around the access channel is locally heated using a laser, causing the substrate material to liquefy locally and, upon solidification, hermetically seal the access channel.

[0005] Another method for setting an internal pressure in a cavity of a micromechanical component is known from DE 195 37 814 A1. Such a method is intended for the production of angular rate sensors and accelerometers. In this process, a multitude of freestanding, thick polycrystalline functional structures are produced on a substrate, with conductor tracks and electrodes buried beneath the functional layers. The micromechanical structures produced in this way are then sealed with a cap wafer. Depending on the application, a suitable pressure is enclosed within the sealed volume.

[0006] In gyroscopes, for example, a very low pressure is confined, such as 1 mbar. This is because some of the moving structures in gyroscopes are driven resonantly. At this low pressure, relatively low voltages can easily induce an oscillation due to the low damping.

[0007] In contrast, with accelerometers, it is undesirable for the sensor to oscillate, which would be possible if an external acceleration were applied. Therefore, these sensors are operated at a higher internal pressure. The internal pressure of an accelerometer is, for example, 500 mbar.

[0008] Further disclosures are found in the publications DE 10 2014 202 801 A1, US 2009 / 0205371 A1, DE 10 2005 060 870 A1, DE 10 2015 224 545 A1 and US 2015 / 0111332 A1. Disclosure of the invention

[0009] The object of the present invention is to provide a method for manufacturing a mechanically robust and long-life micromechanical component in a manner that is simpler and more cost-effective than those found in the prior art. Furthermore, the object of the present invention is to provide a compact, mechanically robust, and long-life micromechanical component compared to those found in the prior art. According to the invention, this applies in particular to a micromechanical component with a (first) cavity. With the method and micromechanical component according to the invention, it is also possible to realize a micromechanical component in which a first pressure and a first chemical composition can be set in the first cavity and a second pressure and a second chemical composition can be set in a second cavity.For example, such a method is provided for the production of micromechanical components for which it is advantageous to have a first pressure enclosed in a first cavity and a second pressure enclosed in a second cavity, the first pressure being different from the second pressure. This is the case, for example, when a first sensor unit for measuring angular rate and a second sensor unit for measuring acceleration are to be integrated into a micromechanical component.

[0010] The task is solved by the fact that -- in a fourth process step, a recess is formed, essentially between the first cavern and the second cavern, for draining at least one first particle type of the first gas mixture and / or at least one second particle type of the second gas mixture.

[0011] This provides a simple and cost-effective method for manufacturing a micromechanical component with a recess that selectively interrupts the first diffusion of the first particle type from the first cavern towards and into the second cavern, and / or the second diffusion of the second particle type from the second cavern towards and into the first cavern. This advantageously reduces or eliminates the presence of the first particle type in the second cavern and / or the presence of the second particle type in the first cavern compared to the prior art. Consequently, the probability of a functional impairment or failure of a first sensor unit located in the first cavern due to particles of the second particle type is reduced.The failure of a second sensor unit located in the second cavern due to particles of the first type can be reduced compared to the prior art. Thus, the present invention provides a method for manufacturing a mechanically robust and long-life micromechanical component in a simpler and more cost-effective manner compared to the prior art.

[0012] The inventive method advantageously avoids or significantly reduces diffusion processes of light gases between a cavern with high internal pressure and a cavern with low internal pressure, for example from the second cavern to the first cavern.

[0013] Furthermore, the method according to the invention is advantageous when a gas, such as molecular hydrogen (H₂) or light noble gases, such as helium (He) and neon (Ne), diffuses through, for example, oxide layers and other layers of the micromechanical component 1 or a MEMS component at temperatures occurring in the field, such as 150°C. For example, such gases are generated during the capping or bonding process due to a chemical reaction. However, such gases also diffuse out of the sensor wafer or cap wafer due to the high temperatures occurring during the capping process. For example, to establish a high internal pressure or a high secondary pressure in the cavity of the accelerometer or in the second cavity, gases such as molecular nitrogen (N₂) are used, which do not diffuse, or diffuse less readily, through, for example, oxide or the oxide layer.For example, the additional gases that arise during the capping process or diffuse out of the substrate or cap and can diffuse readily through oxide or oxide layers constitute only a small fraction compared to the nitrogen (N2). If, for example, the hydrogen diffuses out of the accelerometer cavity or the second cavity over the lifetime of the device, the pressure in the accelerometer cavity or the second cavity changes only slightly. This is less problematic, for example, because accelerometers are insensitive to small pressure changes. It is more critical if, for example, some of the hydrogen diffuses into the yaw rate sensor cavity or the first cavity and, due to the low internal pressure and the high sensitivity of the yaw rate sensor to pressure changes, leads to failure of the yaw rate sensor.

[0014] The method according to the invention is also advantageous when sensor or sensor core surfaces are provided with organic coatings that prevent moving structures from sticking together, and these organic coatings degrade at high temperatures, for example in bonding processes, and are no longer fully effective. The method according to the invention can counteract the at least partial release of the organic layers into the cavity and the resulting increased internal pressure after sealing the MEMS element or micromechanical component in a simple and cost-effective manner.

[0015] According to the invention, a particle is preferably understood to be an atom or a collection of atoms, such as a molecule or several molecules. In the context of the present invention, the particle is in a gaseous, liquid, or solid state of matter or is part of a gaseous, liquid, or solid phase and comprises at least one phase interface with its surroundings. In particular, according to the invention, a particle is understood to be a body small on the scale of the micromechanical component, i.e., a body which has a maximum extent of 1 / 10 of the maximum extent of the micromechanical component.

[0016] According to the present invention, a particle type is understood to be a specific type of particle. For example, the invention provides that the first particle type essentially corresponds to the second particle type. Alternatively, it is also provided, for example, that the first particle type differs from the second particle type. However, the invention also provides that the first particle type and the second particle type each differ from a third particle type. For example, the invention provides that the first particle type and / or the second particle type comprise H₂ and / or a light noble gas such as He and Ne. It is also provided, for example, that the third particle type comprises N₂.

[0017] According to the invention, the recess arranged essentially between the first cavern and the second cavern is understood to mean that the recess is arranged such that the recess at least partially comprises a plane, wherein the plane intersects a straight line connecting the first cavern and the second cavern essentially perpendicularly.

[0018] In the context of the present invention, the term “micromechanical component” is to be understood as encompassing both micromechanical components and microelectromechanical components.

[0019] The present invention is preferably intended for the manufacture of a micromechanical component with two cavities. However, the present invention is also intended, for example, for a micromechanical component with three cavities or with more than three, i.e., four, five, six or more than six, cavities.

[0020] Preferably, the access opening is closed by introducing energy or heat into an energy- or heat-absorbing part of the substrate or cap using a laser. Preferably, energy or heat is introduced sequentially into the absorbing part of the substrate or cap of several micromechanical components, which are, for example, manufactured together on a wafer. Alternatively, however, simultaneous introduction of energy or heat into the respective absorbing part of the substrate or cap of several micromechanical components is also possible, for example, using multiple laser beams or laser devices.

[0021] Advantageous embodiments and further developments of the invention can be found in the dependent claims and in the description with reference to the drawings.

[0022] According to a preferred embodiment, the recess is formed at least partially in a bonding layer located between the substrate and the cap. This advantageously enables the recess to be formed particularly easily and cost-effectively during the bonding process. Furthermore, it advantageously allows the first type of particle and / or the second type of particle to be easily and efficiently diverted into the surrounding environment during diffusion through the bonding layer.

[0023] According to a preferred embodiment, the recess is formed at least partially in a layer arranged between the substrate and the cap. This advantageously allows the recess to be formed particularly easily and cost-effectively during the structuring of the layer. Furthermore, it advantageously enables the first type of particle and / or the second type of particle to be discharged into the environment particularly easily and efficiently during diffusion through the layer.

[0024] According to a preferred embodiment, the recess is formed at least partially in an additional layer arranged between the substrate and the cap. This advantageously allows the recess to be formed particularly easily and cost-effectively when structuring the additional layer. Furthermore, it advantageously enables the first type of particle and / or the second type of particle to be discharged into the environment particularly easily and efficiently during diffusion through the additional layer.

[0025] According to a preferred embodiment, the recess is formed at least partially in the substrate and / or the cap. This advantageously allows the recess to be formed particularly easily and cost-effectively during the structuring of the substrate and / or the cap. Furthermore, this advantageously allows the first type of particle and / or the second type of particle to be discharged into the environment particularly easily and efficiently during diffusion through the substrate and / or the cap.

[0026] A further object of the present invention is a micromechanical component comprising a substrate and a cap connected to the substrate and enclosing a first cavity with the substrate, wherein a first pressure prevails in the first cavity and a first gas mixture with a first chemical composition is enclosed, wherein the cap encloses a second cavity with the substrate, wherein a second pressure prevails in the second cavity and a second gas mixture with a second chemical composition is enclosed, wherein the substrate or the cap comprises a sealed access opening, and wherein the micromechanical component comprises a recess arranged substantially between the first cavity and the second cavity for draining at least one first particle type of the first gas mixture and / or at least one second particle type of the second gas mixture.This advantageously provides a compact, mechanically robust, and cost-effective micromechanical component with preset first and second pressures. The aforementioned advantages of the method according to the invention also apply accordingly to the micromechanical component according to the invention.

[0027] According to a preferred embodiment, the recess is provided for to be located at least partially within a bonding layer positioned between the substrate and the cap. This advantageously enables the recess to be formed particularly simply and cost-effectively during the bonding process. Furthermore, it advantageously allows the first type of particle and / or the second type of particle to be dissipated into the environment particularly easily and efficiently during diffusion through the bonding layer.

[0028] According to a preferred embodiment, the recess is arranged at least partially in a layer positioned between the substrate and the cap. This advantageously allows the recess to be formed particularly easily and cost-effectively during the structuring of the layer. Furthermore, it advantageously enables the first type of particle and / or the second type of particle to be discharged into the environment particularly easily and efficiently during diffusion through the layer.

[0029] According to a preferred embodiment, the recess is arranged at least partially in a further layer positioned between the substrate and the cap. This advantageously allows the recess to be formed particularly easily and cost-effectively when structuring the further layer. Furthermore, it advantageously enables the first type of particle and / or the second type of particle to be discharged into the environment particularly easily and efficiently during diffusion through the further layer.

[0030] According to a preferred embodiment, the recess is arranged at least partially in the substrate and / or in the cap. This advantageously allows the recess to be formed particularly easily and cost-effectively during the structuring of the substrate and / or the cap. Furthermore, this advantageously allows the first type of particle and / or the second type of particle to be discharged into the environment particularly easily and efficiently during diffusion through the substrate and / or the cap.

[0031] According to a preferred embodiment, the first pressure is lower than the second pressure, with a first sensor unit for measuring the angular rate being arranged in the first cavern and a second sensor unit for measuring the acceleration being arranged in the second cavern. This advantageously provides a mechanically robust micromechanical component for measuring angular rate and acceleration, with optimal operating conditions for both the first and second sensor units. Brief description of the drawings Fig. Figure 1 shows a schematic representation of a micromechanical component with an open access opening. Fig. Figure 2 shows a schematic representation of the micromechanical component according to Fig. 1 with a closed access opening. Fig. Figure 3 shows a schematic representation of a method for manufacturing a micromechanical component according to an exemplary embodiment of the present invention. Fig. Figure 4 shows a schematic representation of a micromechanical component known from the prior art. Fig. 5, Fig. 6 and Fig. Figure 7 shows schematic representations of sections of micromechanical components according to exemplary embodiments of the present invention. Embodiments of the invention

[0032] In the various figures, identical parts are always marked with the same reference symbols and are therefore usually only named or mentioned once.

[0033] In Fig. 1 and Fig. Figure 2 is a schematic representation of a micromechanical component 1 with an open access opening 11 in Fig. 1 and with closed access opening 11 in Fig. Figure 2 shows an exemplary embodiment of the present invention. Here, the micromechanical component 1 comprises a substrate 3 and a cap 7. The substrate 3 and the cap 7 are connected to each other, preferably hermetically, and together enclose a first cavity 5. For example, the micromechanical component 1 is configured such that the substrate 3 and the cap 7 additionally enclose a second cavity. The second cavity is in Fig. 1 and in Fig. 2, however, is not shown.

[0034] For example, in the first cavern 5, especially in situations like those in Fig. Figure 2 shows a sealed access opening 11, and a first pressure is present. Furthermore, a first gas mixture with a first chemical composition is enclosed in the first cavity 5. Additionally, for example, a second pressure prevails in the second cavity, and a second gas mixture with a second chemical composition is enclosed in the second cavity. Preferably, the access opening 11 is arranged in the substrate 3 or in the cap 7. In the present embodiment, the access opening 11 is arranged in the cap 7 by way of example. However, according to the invention, it can alternatively be provided that the access opening 11 is arranged in the substrate 3.

[0035] For example, it is planned that the initial pressure in the first cavern 5 will be lower than the second pressure in the second cavern. It is also planned, for example, that a [missing text] will be installed in the first cavern 5. Fig. 1 and Fig. 2 not shown first micromechanical sensor unit for measuring rotation rate and in the second cavern a in Fig. 1 and Fig. 2 second micromechanical sensor units for acceleration measurement are arranged, not shown.

[0036] In Fig. Figure 3 shows a schematic representation of a method for manufacturing the micromechanical component 1 according to an exemplary embodiment of the present invention. In this process, -- in a first process step 101 the access opening 11 connecting the first cavern 5 with an environment 9 of the micromechanical component 1, in particular narrow, is formed in the substrate 3 or in the cap 7. Fig. Figure 1 shows, as an example, the micromechanical component 1 after the first process step 101. Furthermore, -- in a second process step 102, the first pressure and / or the first chemical composition is set in the first cavern 5, or the first cavern 5 is flooded with the desired gas and the desired internal pressure via the access channel. Furthermore, for example -- in a third process step 103, the access opening 11 is closed by introducing energy or heat into an absorbing part of the substrate 3 or the cap 7 using a laser. Alternatively, it is also provided, for example, that -- in the third process step 103, the area around the access channel is preferably heated locally by a laser and the access channel is hermetically sealed. Thus, it is advantageously possible to provide the process according to the invention with energy sources other than a laser for sealing the access opening 11. Fig. Figure 2 shows, by way of example, the micromechanical component 1 after the third process step 103.

[0037] After the third procedural step 103, in a Fig. Mechanical stresses occur in the lateral region 15 of the micromechanical component 1, as illustrated by example in Figure 2, on a surface of the cap 7 facing away from the cavern 5, and in depth perpendicular to a projection of the lateral region 15 onto the surface, i.e., along the access opening 11 and in the direction of the first cavern 5. These mechanical stresses, in particular local mechanical stresses, prevail especially at and near an interface between a material region 13 of the cap 7 that transitions into a liquid state in the third process step 103 and into a solid state after the third process step 103, closing the access opening 11, and a residual region of the cap 7 that remains in a solid state during the third process step 103. Fig. 2 the material area 13 of the cap 7 closing the access opening 11 is to be regarded as merely schematic or is shown schematically, in particular with regard to its lateral extent or shape, especially parallel to the surface, and in particular with regard to its extent or configuration perpendicular to the lateral extent, especially perpendicular to the surface.

[0038] In Fig. Figure 3 shows an example of a fourth process step 104, wherein -- In the fourth process step 104, a recess 1501 is formed, substantially located between the first cavern 5 and the second cavern, for the purpose of extracting at least one first particle type A of the first gas mixture and / or at least one second particle type B of the second gas mixture. In other words, a channel or cavity is created between two MEMS caverns in the fourth process step 104. It is provided, for example, that the recess 1501 is formed at least partially in a bonding layer 1503 located between the substrate 3 and the cap 7. Furthermore, it is provided, for example, additionally or alternatively, that the recess 1501 is formed at least partially in a layer 1505 located between the substrate 3 and the cap 7.Furthermore, it is additionally or alternatively provided that the recess 1501 is formed at least partially in a further layer 1507 arranged between the substrate 3 and the cap 7. Finally, it is additionally or alternatively provided that the recess 1501 is formed at least partially in the substrate 3 and / or in the cap 7.

[0039] For example, it is planned that -- in a fifth process step, the recess 1501 is filled with a filling material. In other words, it is provided, for example, that the recess 1501 comprises a filling material. It is provided, for example, that the filling material is diffusion-open to the first particle type A and / or the second particle type B. In other words, it is provided, for example, that if the channel or recess 1501 is filled, the channel or recess is diffusion-open to the outside or to the environment 9 for light gases. It is provided, for example, that the filling material comprises a plastic potting compound or several plastic potting compounds. It is also provided, for example, that the filling material comprises a synthetic resin, in particular a casting resin. However, according to the invention, the use of a filling material that is diffusion-open to the first particle type A and / or the second particle type B is also permitted.

[0040] In Fig. Figure 4 shows a schematic representation of a micromechanical component 1 known from the prior art. The substrate 3, the first cavity 5, the cap 7, the sealed access opening 11, the solidified material region 13, and the surrounding area 9 are shown as examples. The in Fig. Figure 4 shows an exemplary micromechanical component 1 comprising a first sensor unit 1511 arranged in the first cavern 5 and a second sensor unit 1513 arranged in the second cavern. Furthermore, it shows Fig. 4. For example, a second particle type B arranged in the second cavern, a second particle type B diffusing from the second cavern towards the first cavern 3, and a second particle type B that has already diffused into the first cavern 5 and is arranged in the first cavern. Additionally, in Fig. 4 a third type of particle C arranged, which does not diffuse in the direction of the first cavern 5.

[0041] The in Fig. Figure 4, enlarged, shows substrate 3 and cap 7. It also shows Fig. 4 by way of example a bonding layer 1503, a layer 1505 and a further layer 1507, wherein the bonding layer 1503, the layer 1505 and the further layer 1507 are arranged between the substrate 3 and the cap 7 and substantially between the first cavern 5 and the second cavern.

[0042] Furthermore, in Fig. 5, Fig. 6 and Fig. Figure 7 shows schematic representations of sections of micromechanical components according to exemplary embodiments of the present invention. Here, in Fig. 5, Fig. 6 and Fig. Figure 7 shows by way of example that the micromechanical component 1 comprises a recess 1501 arranged essentially between the first cavern 5 and the second cavern for diverting at least one first particle type A of the first gas mixture and / or at least one second particle type B of the second gas mixture.

[0043] This shows Fig. 5 for example that the recess 1501 is at least partially located in a bonding layer 1503 situated between the substrate 3 and the cap 7. In Fig. Figure 5 shows, by way of example, the cap 7 or cap wafer protecting the MEMS structure, or a first sensor unit 1511 and a second sensor unit 1513. For example, in a sixth process step, the cap 7 or cap wafer is applied to the substrate 3 using a seal glass or a eutectic bond such as an aluminum-germanium (AlGe) alloy or a copper-tin (CuSn) alloy, or using a direct bonding process such as gold-gold (AuAu). For example, the recess 1503 in the bond is designed as a slot-shaped interruption that separates the first cavity 5 from the second cavity, or an accelerometer from a gyroscope, and extends to the edge of the chip at least on one side, or is substantially perpendicular to the image plane. Fig. 5 is at least on one side of the micromechanical component 1 in contact with the environment 9 or is otherwise open or connected to the environment 9. This can be achieved, for example, by also exposing the channel or recess 1501 along with the contact surfaces, in particular a first surface of the cap 7 and a second surface of the layer 1505. This advantageously allows the channel or recess 1501 to be formed very early in the process, before the chips are singulated.

[0044] For example, according to the invention, a stop structure 1509 is arranged between the substrate 3 and the cap 7, and substantially between the first cavity 5 and the cavity between the two cavities. Alternatively, it is also provided, for example, that two, three, four, five, six, or more than six stop structures 1509 are arranged between the substrate 3 and the cap 7, and substantially between the first cavity 5 and the cavity between the two cavities. For example, it is provided that the stop structure 1509 or the stop structures 1509 are arranged in contact with the substrate 3 and / or the cap 7, respectively. This is exemplified in Fig. Figure 5 illustrates this. Such a stop structure 1509 is advantageous, for example, for bond connections that become liquid, smear, or are squeezed out, since a reliably open channel or recess 1501 can be realized in this way. Furthermore, a particularly narrow recess 1501 can be realized using one or more stop structures 1509.

[0045] Furthermore, it is also possible, as an alternative or additional option, for the recess 1501 to be formed at least partially in layer 1505. For this purpose, it is planned, for example, that a groove is etched into the uppermost MEMS layer or layer 1505 on the sensor wafer to create a channel or recess 1501 in the bond connection. In particular, it is planned that the recess 1501 is designed in such a way that the bonding material does not enter or close the recess 1501. In other words, the slot or recess 1501 is chosen to be narrow enough so that the bonding material cannot penetrate the slot.

[0046] Furthermore, it is also provided, for example, that a depression is created or formed below layer 1505, or below the MEMS layer, or on a side of layer 1505 facing substrate 3. For example, it is provided that the depression is formed in substrate 3 or in the subsequent layer 1507. The depression is formed, for example, by means of an etching step. It is also provided, for example, that the depression is formed before the deposition or growth of layer 1505. Thus, it is advantageously possible that, depending on the manufacturing process, the depression is mapped upwards or towards cap 7 as a topography over the MEMS layer or over layer 1505, and thus a recess 1501 is formed on a side of layer 1505 facing cap 7.For example, it is intended that a bonding process is used, whereby the bonding material used in the bonding process is not able to compensate for the topography, so that the recess 1501 remains formed even after the bonding process.

[0047] For example, it is provided that the MEMS functional layer, or layer 1505, is bonded to substrate 3. For example, a direct bonding process is used. For example, it is provided that layer 1505 is bonded to substrate 3 before the cap wafer, or cap 7, is applied to layer 1505. For example, the recess 1501, or channel, is created or arranged under the functional layer, or under layer 1505. For example, the recess is formed in layer 1505. In other words, a groove is provided in the substrate and / or a groove is etched into the underside of the MEMS functional layer or into a side of layer 1505 facing substrate 3. For example, it is also provided that the groove in substrate 3, particularly in the case of direct bonding, represents a minimal topographical difference.Finally, it is also provided, for example, that, particularly in the case of direct bonding, the preconditioning of at least one of the two bonding partners, in particular at least the layer or substrate 3, is disturbed locally in a strip between the first cavern 5 and the second cavern or between the accelerometer cavern and gyroscope cavern in order to create a strip without connection, which can also act like a channel or fulfill the function of the recess 1501 or is designed as a recess 1501.

[0048] Furthermore, it shows Fig. Figure 6 shows, for example, that the recess 1501 is at least partially located in a layer 1505 situated between the substrate 3 and the cap 7. Furthermore, it shows Fig. 6. By way of example, the recess 1501 is further arranged, at least partially, in a further layer 1507 located between the substrate 3 and the cap 7. Here, for instance, it is provided that the recess 1501 is formed by means of access holes 1515 in layer 1505 and an isotropic etching step. In other words, a channel or recess 1501 is created under the uppermost MEMS functional layer or on a side of layer 1505 facing the substrate 3. For example, it is provided that a series or a multitude of access holes 1515 are first created in the uppermost MEMS layer or in layer 1515, and subsequently, using an isotropic etching step, for example with hydrogen fluoride (HF) gas phase etching, the underlying layer or the further layer 1507, wherein layer 1507 comprises, for example, an oxide layer, is etched until a continuous channel orThe recess 1501 is located in the material beneath the MEMS layer or in the further layer 1507. For example, it is provided that the micromechanical component comprises a series or a plurality of access holes 1515. This advantageously allows the mechanical stability of the MEMS layer or layer 1505 to be only minimally affected or to exhibit sufficient mechanical stability for the functionality of the micromechanical component 1. Alternatively, it is also provided, for example, that a continuous recess, particularly one essentially perpendicular to the image plane, is located in the MEMS layer. Fig. 6. A continuous channel is generated. This is particularly advantageous when a particularly weight-saving and material-saving design is desired and the mechanical stability is sufficient for the functionality of the micromechanical component 1 despite the continuous channel. Thus, it is advantageously possible to use standard manufacturing steps of the MEMS process in the inventive method for forming the channel or recess 1501.

[0049] Finally, it shows Fig. 7. For example, the recess 1501 is arranged at least partially in the substrate 3. Alternatively or additionally, it is also provided that the recess 1501 is arranged at least partially in the cap 7. Additionally, it is also provided that the recess 1501 is arranged at least partially in a conductor track buried in the substrate 3. Furthermore, it is also provided that the recess 1501 is arranged at least partially in a third layer.

[0050] Furthermore, according to the invention, it is also provided, for example, that a narrow trench is etched in the substrate 3, or in a conductor track buried in the substrate 3, or in the further layer 1507, or in a conductor track buried in the further layer 1507, or in a third layer, or in a conductor track buried in the third layer, such that in a subsequent deposition or growth process step, the trench fills in, but a cavity or recess 1501 is formed due to the profile of the trench. According to the invention, it is also provided, for example, that such a recess 1501 is produced or formed using several combined etching and deposition processes.

[0051] According to the invention, it is also provided, for example, that in the fourth process step further recesses, in particular one or two or three or four or five or six or more than six further, are formed, essentially between the first cavern 5 and the second cavern, for draining at least one first particle type A of the first gas mixture and / or at least one second particle type B of the second gas mixture. Fig. Figure 7 shows three examples of exceptions from 1501. For example, it is also provided that the in Fig. 5, Fig. 6 and Fig. The 7 exemplary recesses shown in 1501 can be combined with each other as desired.

[0052] For example, it is provided that the second particle type B comprises molecular hydrogen (H2). This advantageously provides a method by which, for example, the diffusion of H2 from one MEMS cavern or from the second cavern to another MEMS cavern or to the first cavern 5 is prevented or reduced compared to the prior art. Alternatively or additionally, it is also provided, for example, that the second particle type B comprises other light gases. This advantageously enables, for example, the diffusion of light gases from one MEMS cavern or from the second cavern to another MEMS cavern or to the first cavern 5 to be prevented or reduced compared to the prior art. For example, it is provided that the first particle type A is a particle of a first light gas and the second particle type B is a particle of a second light gas.For example, it is stipulated that the first light gas is identical to the second light gas. Alternatively, it is also stipulated that the first light gas is different from the second light gas.

[0053] Furthermore, it is provided, for example, that the micromechanical component 1 includes a second access opening connecting the recess 1501 and the surrounding area 9. It is also provided, for example, that the micromechanical component 1 includes a third access opening connecting the recess 1501 and the surrounding area 9. For example, it is provided that the second access opening and / or the third access opening are substantially perpendicular to the image planes of the Fig. 5, Fig. 6 and Fig.7 is formed. In a connection between the recess 1501 and the environment 9, it is advantageous that the partial pressure of light gases such as H2, He and Ne in air is extremely low, and that thus, for example, gas diffusing from the accelerometer cavern or from the second cavern into the channel or into the recess 1501 is directed outwards or towards the environment 9. Thus, it is advantageously achieved that the gas does not diffuse further into the yaw rate sensor cavern or into the first cavern.

[0054] Finally, for example, it is provided that in the fourth process step 104, a recess, arranged essentially between the first cavity 5 and the second cavity, is formed in several micromechanical components 1 of a wafer before the micromechanical components 1 are separated from one another. However, it is also provided, for example, that several micromechanical components 1 of a wafer are first separated from one another and then, in the fourth process step 104, a recess, arranged essentially between the first cavity 5 and the second cavity, is formed in several micromechanical components 1.

Claims

[1] Method for producing a micromechanical component (1) with a substrate (3) and with a cap (7) connected to the substrate (3) and enclosing a first cavity (5) with the substrate (3), wherein a first pressure prevails in the first cavity (5) and a first gas mixture with a first chemical composition is enclosed, wherein the cap (7) encloses a second cavity with the substrate (3), wherein a second pressure prevails in the second cavity and a second gas mixture with a second chemical composition is enclosed, wherein -- in a first process step (101) an access opening (11) connecting the first cavern (5) with a surrounding (9) of the micromechanical component (1) is formed in the substrate (3) or in the cap (7), wherein -- in a second process step (102) the first pressure and / or the first chemical composition is set in the first cavern (5), wherein -- in a third process step (103) the access opening (11) is closed by introducing energy or heat into an absorbing part of the substrate (3) or the cap (7) using a laser, characterized by , that -- in a fourth process step (104) a recess (1501) arranged essentially between the first cavern (5) and the second cavern is formed for the purpose of diverting at least one first particle type (A) of the first gas mixture and / or at least one second particle type (B) of the second gas mixture, wherein the recess (1501) forms a second access opening connected to the surroundings (9). [2] Method according to claim 1, wherein the recess (1501) is formed at least partially in a bond layer (1503) arranged between the substrate (3) and the cap (7). [3] Method according to one of the preceding claims, wherein the recess (1501) is formed at least partially in a layer (1505) arranged between the substrate (3) and the cap (7). [4] Method according to one of the preceding claims, wherein the recess (1501) is formed at least partially in a further layer (1507) arranged between the substrate (3) and the cap (7). [5] Method according to one of the preceding claims, wherein the recess (1501) is formed at least partially in the substrate (3) and / or in the cap (7). [6] Micromechanical component (1) comprising a substrate (3) and a cap (7) connected to the substrate (3) and enclosing a first cavity (5) with the substrate (3), wherein a first pressure prevails in the first cavity (5) and a first gas mixture with a first chemical composition is enclosed, wherein the cap (7) encloses a second cavity with the substrate (3), wherein a second pressure prevails in the second cavity and a second gas mixture with a second chemical composition is enclosed, wherein the substrate (3) or the cap (7) comprises a sealed access opening (11), characterized by , that the micromechanical component (1) comprises a recess (1501) arranged substantially between the first cavern (5) and the second cavern for diverting at least one first particle type (A) of the first gas mixture and / or at least one second particle type (B) of the second gas mixture, wherein the recess (1501) forms a second access opening connected to the surroundings (9). [7] Micromechanical component (1) according to claim 6, wherein the recess (1501) is arranged at least partially in a bonding layer (1503) arranged between the substrate (3) and the cap (7). [8] Micromechanical component (1) according to claim 6 or 7, wherein the recess (1501) is arranged at least partially in a layer (1505) arranged between the substrate (3) and the cap (7). [9] Micromechanical component (1) according to claim 6, 7 or 8, wherein the recess (1501) is arranged at least partially in a further layer (1507) arranged between the substrate (3) and the cap (7). [10] Micromechanical component (1) according to claim 6, 7, 8 or 9, wherein the recess (1501) is arranged at least partially in the substrate (3) and / or in the cap (7).

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