CN114538365A

CN114538365A - Micromechanical component

Info

Publication number: CN114538365A
Application number: CN202111413608.3A
Authority: CN
Inventors: H·韦伯; P·施莫尔格鲁贝尔; T·弗里德里希
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-11-25
Filing date: 2021-11-25
Publication date: 2022-05-27
Also published as: DE102020214792A1

Abstract

A micromechanical component (100) having: -a covering element (10); -a cavity (20) arranged below the covering element (10); -at least one vertical etched channel (11) arranged outside the anchoring structure of the covering element (10); -at least one lateral etching channel (12a.. 12n) arranged below the etch stop layer (3) and below the cavity (20) and arranged between the etch stop layer (3) and the silicon substrate (1) starting from the at least one vertical etching channel (11); and-at least one via-etched channel (3a1...3an) configured between the at least one lateral etched channel (12a.. 12n) and the cavity (20).

Description

Micromechanical component

Technical Field

The invention relates to a micromechanical component. The invention also relates to a method for producing a micromechanical component.

Background

In the production of surface micromechanical sensors, such as inertial sensors or pressure sensors, the following requirements exist: must be assisted by etching vias

Removing sacrificial layers from the cavity region to enable the fabrication of freely movable structures, e.g.A movable material or a membrane. These etched vias must usually be closed again after removal in order to be able to achieve a defined internal chamber pressure.

However, for example in the case of pressure sensors, an etching path leading directly from the upper side of the layer system into the cavity region may lead to a reduced membrane stability. In the variant with an etched channel outside of at least one cavity region, it must be ensured for this purpose that the transverse etched channel cross section is sufficiently large, otherwise a sufficiently large number of etched channels are present

So that a rapid, uniform and complete removal of the sacrificial layer in the functional layer system can be ensured. However, in the production of larger etching channel cross sections within the functional layer system, there are often limitations due to the existing layer thicknesses and lateral layer dimensions required for the realization of the sensor element.

However, due to the ever-increasing miniaturization, the geometries available for the production of etching channels in functional layer systems are decreasing. In order to avoid undercutting of, for example, a polysilicon conductor track during sacrificial layer etching

The sacrificial layer conductor tracks and further layers of the functional layer system are ideally deposited on an electrically insulating layer which is resistant to etching with respect to the following media: the sacrificial layer in the etching channel and/or in the cavity region is removed by means of the dielectric. Below this etch stop layer there may be further layers constituting a substructure (Unterbau) of the sensor element.

In both etching-via variants, the electrical conductor tracks have to be routed from the cavity region for the functionality of the sensor element to be produced. For this purpose, the lateral etching limits around the cavity region have to be interrupted. If the electrically insulating layer surrounding the electrical conductor tracks is also formed here from the material of one or more sacrificial layers (for example SiO2), the etching/removal of the electrically insulating layer is also carried out along the conductor track structure. If a longer etching time is required to remove the sacrificial layer in the cavity region, a large area removal of the sacrificial layer material may also be performed outside the cavity region. Due to the increasing miniaturization and the short path between adjacent components/sensors associated therewith, undesired corrosion in adjacent components or undesired ventilation paths to the cavity may result therefrom.

Disclosure of Invention

It is an object of the present invention to provide an improved micromechanical component, in particular with respect to the above-mentioned aspects.

According to a first aspect, the object is achieved by a micromechanical component having:

-a covering element;

-a cavity arranged below the covering element;

-at least one vertical etched channel arranged outside the anchoring structure of the covering element;

-at least one lateral etching channel provided below the etch stop layer and below the cavity starting from the at least one vertical etching channel and arranged between the etch stop layer and the silicon substrate; and

-at least one via-etched channel configured between the at least one lateral etched channel and the cavity.

According to a second aspect, the object is achieved by a method for producing a micromechanical component, having the following steps:

-constructing a cavity below the covering element;

-constructing at least one vertical etched channel arranged outside the anchoring structure of the covering element; the construction of the cavity is carried out by means of at least one lateral etching channel and at least one via etching channel opening into the cavity, the at least one lateral etching channel being arranged below the etch stop layer and below the cavity, proceeding from the vertical etching channel, and being arranged between the etch stop layer and the silicon substrate.

In this way, the cavity region underneath the cover element can advantageously be emptied from underneath by the only vertical etching via which extends into the lateral etching via. In this way the cover element and the electrical printed conductor can advantageously be largely unaffected by the laterally etched channels. It is advantageously possible to create a woven network of transverse etching channels (Geflecht) starting from the vertical etching channels, if necessary, so that the etching channels can be formed in a simple manner from below into the cavity region.

In this way it can be advantageously supported: at least one lateral etching channel can be provided at a defined position below the cavity region and below the etch stop layer, from which at least one via etching channel can be provided through the etch stop layer for the etching-technical emptying of the cavity region from below.

The gaseous etching medium for emptying the cavity region can thereby be distributed in an efficient manner. In this way, the chamber region can advantageously be emptied from below in a relatively short time, not only from the side, as is conventionally provided, but also from the side, as a function of the principle, with a relatively long etching time.

In this way, the etching medium can advantageously be distributed very efficiently in the cavity region, wherein the etching front can enter the cavity region from below starting from at least one via etching channel through the etch stop layer and at least one lateral etching channel between the etch stop layer and the substrate. In this way, it is possible, as a result, to empty a large cavity region quickly and efficiently from below over a large area.

A preferred embodiment of the micromechanical component can be realized by the measures listed in the preferred embodiments.

An advantageous embodiment of the micromechanical component is characterized in that the vertical etching channel is formed as a slotted cylinder or tube. Different geometries of the vertical etched channels are thereby advantageously obtained.

A further advantageous embodiment of the micromechanical component is characterized in that at least one electrically conductive and/or electrically insulating limiting element, which laterally limits the at least one lateral etching channel, is formed in the first silicon dioxide layer.

In this way, electrically conductive "Si Plugs" (Si Plugs) can be formed, by means of which a multiplicity of possibilities for electrically contacting different elements of the micromechanical component are advantageously created. In this way, for example, electrical substrate contacts can also be realized via vertical etching channels. Furthermore, at least one delimiting element can be provided as a lateral etch stop structure in the production of at least one lateral etch channel. In a variant with a non-conductive limiting element, the advantages described can also be achieved. In both variants, it is essential that the delimiting elements are resistant to etching or have a lower etching rate with respect to the etching medium used for removing the sacrificial layer or layers in the cavity region.

A further advantageous embodiment of the micromechanical component is characterized in that the vertical etched channel is electrically conductively connected to the cover element or electrically insulated from the cover element. In this way, different possibilities for electrically contacting the cover element can be achieved.

A further advantageous embodiment of the micromechanical component is characterized in that the at least one lateral etching channel is delimited in the first silicon dioxide layer by at least one electrically conductive or electrically insulating delimiting element that is resistant to etching by the sacrificial layer etching medium. In this way, the vertical etched channels can be electrically conductively connected to the remaining layer system or insulated therefrom.

A further advantageous embodiment of the micromechanical component is characterized in that the at least one lateral etching channel is at least partially formed in or at least partially above the substrate. This advantageously enables a larger cross section to be formed for the at least one lateral etching channel.

A further advantageous embodiment of the micromechanical component is characterized in that a plurality of lateral etching channels are formed proceeding from the at least one vertical etching channel and/or proceeding from the at least one lateral etching channel, wherein the plurality of lateral etching channels are formed in a mesh-like and/or parallel manner. In this way, the overall dimensioning of the lateral etching channels (dimensioning) can advantageously be achieved.

Drawings

The invention is described in detail below with additional features and advantages based on a number of figures. Identical or functionally identical elements have the same reference numerals here. The drawings are particularly intended to illustrate principles essential to the invention and are not necessarily to scale. For clarity, not all reference numerals may be designated in all figures.

Shown in the drawings are:

fig. 1 to 3: a cross-sectional view of a conventional micromechanical component;

FIG. 4: a cross-sectional view of an embodiment of the proposed micromechanical component;

fig. 5 to 7: alternative variants for providing the etched channels of the proposed micromechanical component;

FIG. 8: a cross-sectional view of an embodiment of the proposed micromechanical component;

FIG. 9: a cross-sectional view of another embodiment of the proposed micromechanical component;

fig. 10 to 14: a cross-sectional view of a lateral etched channel through the proposed micromechanical component;

fig. 15 to 18: a cross-sectional view of a lateral etched channel through the proposed micromechanical component;

fig. 19 to 23: a cross-sectional view of a lateral etched channel through the proposed micromechanical component;

fig. 24 to 28: a cross-sectional view of a laterally etched channel through the proposed micromechanical component;

fig. 29 to 31 show top views of embodiments of the micromechanical component; and

FIG. 32: a principle process for manufacturing the proposed micromechanical component.

Detailed Description

The core idea of the invention is in particular to realize the following etched channel structure: the etched channel structure is independent of the layers and layer thicknesses of the functional layer system used for producing the sensor element and, for example, enables the use of only SiO along the conductor track structure outside the cavity region₂The layer is subjected to a small amount of etching.

For this purpose, it is provided that the etching channels are not provided in the layers within the functional layer system that are necessary for the realization of the mechanical and electrical functions of the sensor element, but rather in their substructure. In this connection, "substructure" is understood to mean a layer system between an etch stop layer (for example silicon-rich silicon nitride, SiRiN) and a silicon substrate.

In the prior art, basically two types of etched vias are known. For example, etching vias in the cavity region are known which lead directly from the upper side of the layer system into the cavity region. Etching passages are also known which lead from the upper side of the layer system, however from outside the cavity region, via lateral etching channels within the layer system into the cavity region. In this variant, the lateral etching channels are guided through the cavity wall generally orthogonally within the functional layer system.

Fig. 1 shows a cross section through a conventional micromechanical component 100 in the form of a sensor element, which has a Si substrate 1 (silicon substrate) and a first silicon dioxide layer 2 arranged thereon. An etch stop layer 3 is disposed on the first silicon dioxide layer 2. A first functional layer 4 is present on the etch stop layer 3. A second silicon dioxide layer 5 is arranged on the first functional layer 4, on which second silicon dioxide layer a second functional layer 6 is arranged. A third silicon dioxide layer 7 is arranged on the second functional layer 6, on which a third functional layer 8 is arranged, from which a covering element 10, for example in the form of a film or a cap element, is subsequently formed. For example, polycrystalline silicon, preferably polycrystalline silicon provided with dopants, can be used as the material for the

functional layers

4, 6, 8.

At least one vertical etched channel 11 is led through the cover element 10, which terminates in a cavity region 7a (subsequent cavity 20) on the third silicon dioxide layer 7. The silicon dioxide material is removed from the cavity region 7a by means of an etching medium, for example a liquid or a gas with HF, via at least one vertical etching channel 11. As is shown in fig. 2, the cavity 20 is formed here or thereby below the cover element 10. The vertical etched channels 11 are then closed with a closing element 11 a. In this case, it can be problematic that during the emptying of the chamber region 7a by means of the etching medium along the electrical conductor tracks 4a of the first functional layer 4, which lead out of the chamber region 7a, uncontrolled etching X can occur along the conductor tracks 4a and within the functional layer system. This occurs in particular even if the electrical printed conductor 4a of the first functional layer 4 is at least partially surrounded by silicon dioxide for the purpose of electrical insulation.

An improvement of the mentioned case may consist in arranging at least one vertical etched channel 11 in a laterally spaced manner from the anchoring structure of the cover element 10 in an area outside the cavity 20, as is illustrated in fig. 3, whereby the cover element 10 is no longer damaged. However, in this case, the following problems may still occur: the electrical conductor tracks 4a formed in the first functional layer 4 in the region around the lateral etching channels 12a formed in the functional layer system are disadvantageously attacked.

In the prior art, the etching channels from outside the cavity region end at the cavity wall and can from there remove the sacrificial layer in the cavity region 7 a. Since a longer etching time can occur here depending on the size of the cavity region 7a, the insulating layer surrounding the following conductor tracks 4a is subjected to an etching action for a particularly long time: the conductor tracks emerge from the chamber 20 in the vicinity of or in the region of the etched channels through the chamber wall.

For improvement, at least one lateral etching channel 12a is provided, which is arranged in a substructure of the proposed micromechanical component 100, which may end at any point below the cavity region 7a, for example, and at least one via etching channel 3a1 runs along the substructure from the lateral etching channel 12a through the etch stop layer 3 to the cavity region 7a or into the cavity region 7a, from where the sacrificial layer in the cavity region 7a can be removed, as is shown in fig. 4 in an embodiment of the proposed micromechanical component 100. Similar to the etching paths which are introduced directly into the cavity region 7a starting from the surface via the at least one vertical etching path 11, the at least one via etching path 3a1, 3b through the etch stop layer 3 and the at least one lateral etching path 12a and can be arranged at will, one or more via etching paths 3a.. 3n can also be positioned in the substructure in such a way that a smooth, uniform and complete removal of the sacrificial layer can be ensured without the need to carry out, for example, perforation of the cover element 10 and thus to withstand mechanical constraints and/or greater design constraints in the functional layer system.

The proposed construction of one or more lateral etched channels 12a.. 12n in the substructure additionally offers the following possibilities with respect to conventional micromechanical components: placing an interwoven network of etched channels, for example below the cavity region 7a, requires only a single vertical etched via 11 at the upper side of the functional layer system. By positioning the one or more via-etched channels 3a1...3an, more so to speak, centrally below the cavity region 7a, it is possible to: by removing the sacrificial layer from the center of the cavity, removal of insulating or sacrificial layer material along the conductor tracks 4a, 4b outside the cavity region 7a can be avoided, at least strongly minimized.

In the illustrated variant of the proposed micromechanical component 100, the walls of the cavity region 7a and of the

etching channels

11, 12a.. 12n through the functional layer system are made of silicon by way of example. The polysilicon layer in the functional layer system is used here not only for realizing the lateral etch limit structure, but also for realizing it (for example from SiO)₂Formed) electrically between polysilicon layers within the electrically insulating layer. In principle, however, it is also possible to: if the electrically insulating material has a high etching resistance with respect to the etching medium used for removing the sacrificial layer or layers, the electrically insulating material is used for lateral etch protection boundaries, for example SiRiN when HF vapor is used as the etching medium.

The production of an etching channel in the functional layer system substructure made of the first silicon dioxide layer 2 between the etching stop layer 3 made of SiRiN and the silicon substrate 1 can be carried out by way of example as follows:

at least one first silicon dioxide layer 2 is deposited or thermally grown on the substrate 1 and is structured in a standard manner in such a way that, in defined regions, the first silicon dioxide layer 2 is removed in addition to the substrate 1. This can be done by means of a plasma etching process or by wet chemical etching (e.g. in BOE). These structures can be filled subsequently by means of a subsequent deposition of an etch stop layer 3. Is designed accordinglyIn the case of these structures, these structures can form the walls of the etching channels and be used in a later etching process to remove SiO in the cavity region₂The sacrificial layer serves as a lateral etch stop structure.

It is also conceivable to fill these structures with silicon, for example by means of LPCVD deposition. A deposition of an etch stop layer 3 can then be carried out on this silicon layer or the polysilicon layer can be removed on the first silicon dioxide layer 2, for example by a CMP method, so that polysilicon remains only in the exposed structure of the first silicon dioxide layer 2. Surface removal of the polysilicon layer on the oxide may be necessary if as little parasitic capacitance as possible should be formed between the electrically active layer of the functional layer system of the component 100 and the substrate 1.

Filling the structure in the first silicon dioxide layer 2 with electrically conductive polysilicon (Polysilizium) has the following advantages with respect to the filling of the exposed structure by means of an electrically insulating material, such as SiRiN: in this case, the substrate 1 can also be electrically connected or connected in a targeted manner in order to place it at a defined potential. In order to increase the conductivity of the polysilicon structure through the first silicon dioxide layer 2, the polysilicon can additionally be doped in a targeted manner during the deposition, but also in a subsequent step. Lateral etch limits and one or more electrical contacts of the substrate 1 can thus be realized by means of a polysilicon filling.

Fig. 4 depicts a cross section through a micromechanical component 100 produced in this way, in which at least one vertical etching channel 11 has been provided in the functional layer system outside the cavity region 7a, which vertical etching channel is connected via a via etching channel 3b in the first functional layer 4 and the etch stop layer 3 to a lateral etching channel 12a.. 12n in the substructure of the micromechanical component 100, which lateral etching channel is in turn connected via a via etching channel 3a1 in the first functional layer 4 and the etch stop layer 3 to the cavity region 7 a. The at least one vertical etching channel 11 can be embodied here in the form of a slot or a tube.

By removing the oxide material in the vertical etching channels 11, whose walls advantageously consist of, for example, silicon, within the functional layer system and the oxide material within the lateral etching channels 12a.. 12n in the substructure of the micromechanical component 100, at least one via to the cavity region 7a of the micromechanical component 100 can be created via the via etching channels 3a1...3an, 3b, by means of which at least one sacrificial layer, consisting of, for example, SiO2, in the cavity region 7a can be removed. Due to the position of the lateral etch channels 12a.. 12n in the substructure of the sensor element 100, via-etch channels 3a1...3an can be created in this way at any defined position within the cavity region 7a, via which via-etch channels at least one sacrificial layer can be removed from the cavity region 7 a. In this way, measures for realizing etched channels in the functional layer system or measures which significantly limit the design do not have to be taken into account when designing the sensor.

The silicon dioxide in the etching channels 11, 3a1...3an, 3b, 12a.. 12n and in the cavity region 7a can be removed by means of an HF vapor etching process or by means of a wet-chemical etching process with HF (for example BOE).

Fig. 5 to 7 show a plurality of possibilities for constructing via etching channels 3a1...3an and 3b from the functional layer region through the etch stop layer 3 to the substructure.

For example, fig. 5 shows how etching vias 3a1, 3b can be etched through the first functional layer 4 and the etch stop layer 3 by means of the mask layer and the resulting recess can subsequently be filled with a second silicon dioxide layer 5.

Fig. 6 shows a further possibility, in which the etch stop layer 3 and subsequently the first functional layer 4 are first structured by means of two mask layers in such a way that, in the region of the via-etched channel structures 3a1, 3b, the channel structures formed by the etch stop layer 3 are formed in the region of the openings of the channel structures formed by the first functional layer 4, and the resulting recesses/channel structures are subsequently filled with the silicon oxide material of the second silicon oxide layer 5.

Fig. 7 shows a further variant in which the etch stop layer 3 is first structured, then the first functional layer 4 is deposited and structured such that the channel structures through the first functional layer 4 are located in the open regions of the via-etched channel structures 3a1, 3b through the etch stop layer 3, and the recess/etched via channel structures 3a1, 3b produced there are subsequently filled with the silicon dioxide material of the second silicon dioxide layer 5.

By using an electrically insulating etch stop layer 3 it is possible to achieve: the vertical etching channel 11 through the functional layer system is designed to be electrically insulated from the substructure of the functional layer system, as is illustrated in fig. 8.

This can be used to electrically connect the at least one electrical conductor track 4a of the functional layer system via the at least one vertical etching channel 11 with its conductive wall composed of polysilicon and/or to electrically connect one or more electrically conductive limiting elements 13a.. 13n in the form of Si structures in the first silicon dioxide layer 2 via which the substrate 1 can also be electrically connected by providing one or more corresponding contacts through the etch stop layer 3, as is indicated in fig. 9. In this way, the substrate 1 can be electrically contacted at the same time also via the vertical etching channels 11 through the functional layer system. In contrast, if an electrically insulating layer (for example SiRiN) is used to laterally etch-limit the etch channels in the first silicon dioxide layer, the substrate contacts have to be produced by means of further process steps, which can lead to additional costs.

Instead of the described production of the electrically conductive limiting element 13a in the first silicon dioxide layer 2, it is also possible to structure the Si structure, which is intended, for example, for lateral etching limiting of the at least one lateral etching channel 12a.. 12n and/or for electrically contacting the substrate 1 in the first silicon dioxide layer 2 in the substructure of the sensor element 100, first from the substrate 1 by means of a mask layer, as is shown in fig. 10, and then, as can be seen in fig. 11, by means of SiO₂The deposition of the layer is covered.

If a CMP process is subsequently carried out to planarize the wafer surface, the raised electrical limiting elements 13a.. 13n can be exposed again and SiO can remain between these limiting elements as indicated in fig. 12₂And (3) a layer. By means of closely juxtaposed electrically conductive limiting elements 13a.. 13n and non-conformal SiO₂Deposition, it being possible here to achieve incomplete SiO₂Filling the space between the electrically conductive limiting elements 13a.. 13nAnd (3) removing the solvent. This results in incompletely filled lateral etched channels 12a.. 12n or an incompletely filled lateral etched channel system in the first silicon dioxide layer 2 of the substructure, as a result of which the etching medium (for example HF vapor) can propagate significantly faster through the lateral etched channels 12a.. 12n to the via etched channels 3a1...3an in the cavity region 7 a.

As a result, in this way it is possible to achieve: a fast etching action of the sacrificial oxide layer in the cavity region 7a is achieved even when longer lateral etching channels 12a.. 12n are used. Furthermore, a polysilicon deposition step for filling the exposed structures in the first silicon dioxide layer 2 and possibly a downstream doping step can be saved in this method.

Fig. 13 shows the substructure described in fig. 12 with a part of the subsequently deposited functional layer system. Fig. 14 shows lateral etch channels 12a to 12c through the functional layer system after the sacrificial oxide layer in the cavity region 7a has been etched. In this variant, at least one vertical etching channel 11 in the functional layer system can be realized in such a way that the vertical etching channel 11 is split into a plurality of etching channel structures which open into the lateral etching channels 12a to 12 c.

Thus, as can be seen in fig. 10 to 14, the plurality of laterally etched channel structures 12a.. 12n in the first silicon dioxide layer 2 can also be connected to only one vertically etched channel 11 in the functional layer system, when the vertically etched channel 11 in the functional layer system is correspondingly designed. This may advantageously be used to enlarge the effective cross-section of the lateral etched channels 12a.. 12 n. Furthermore, a plurality of lateral etching channels 12a.. 12n, which extend, for example, in different directions (i.e., in a network) can be connected to the vertical etching channels 11 in this way, starting from the at least one vertical etching channel 11, through the functional layer system. For this purpose, the splitting of the at least one vertical etching channel 11 does not necessarily have to be carried out in the functional layer system. Instead, the at least one vertical etching channel 11 can also open into the at least one lateral etching channel 12a.. 12n and, from there, be distributed over a plurality of lateral etching channels 12a.. 12 n.

Alternatively to the method illustrated in fig. 10 to 14, the enlargement of the cross section of the lateral etching channel can also be achieved by: first, trenches are etched into the substrate 1 in the region of the lateral etching channels 12a.. 12n and are closed by means of the first silicon dioxide layer 2 in such a way that cavities 2a.. 2n are formed in them, as is shown in fig. 15 and 16.

By means of the production steps already described in connection with fig. 4, lateral etch limits can now be produced in the first silicon dioxide layer 2 and other functional layer structures can be realized. When removing the sacrificial oxide layer in the cavity region 7a, the etching medium can be distributed quickly along the cavities 2a.. 2n in the trenches even in long lateral etching channels 12a.. 12n, and thus a significantly reduced sacrificial oxide layer etching time compared to completely filled trenches can advantageously be achieved.

If the configuration of the parasitic capacitances between the functional layer system and the substrate 1 is not of any significance, the layer system of the substructure and therefore the first silicon dioxide layer 2 mentioned in the example shown can also be omitted with reference to fig. 15 to 18.

As shown in fig. 19 to 23, for this purpose, the deposited first silicon dioxide layer 2 can be removed, for example, by means of a CMP process (chemical mechanical polishing), in such a way that the cavities produced in the lateral trench channels 12a.. 12n remain closed by the material of the first silicon dioxide layer 2, while the first silicon dioxide layer 2 is completely removed on the remaining substrate 1. The already described production process for realizing the functional layer system with optional electrical contacting of the substrate 1 follows after partial removal of the first silicon dioxide layer 2.

Another variant for producing the lateral etching channels 12a. In this case, first a first silicon dioxide layer 2 is produced on the substrate 1 and is structured in such a way that silicon is removed from the substrate 1 through the openings produced in this case, as is shown in fig. 24 and 25. After the etching of the substrate 1, the opening in the first silicon dioxide layer 2 is closed by means of the second silicon dioxide layer 5 in such a way that a cavity 1a.. 1n is formed in the substrate 1, as can be seen in fig. 26.

Depending on the choice of the etching process (isotropic, anisotropic, a combination of both), it is thus possible to produce individual transverse channel structures 12a.. 12n (as indicated in fig. 24) and/or transverse channel structures with a large channel cross section (as indicated in fig. 25). If the openings in the first silicon dioxide layer 2 are made small or narrow, these openings can be closed quickly. Thereby, only slight topographical differences (topographies) are produced at the upper side of the closing layer (in this case the second silicon dioxide layer 5), which makes an additional CMP step for producing a planar surface unnecessary.

This variant has the following advantages with respect to the variant described in connection with fig. 10 to 14: the channel structure in the substrate 1, below the first silicon dioxide layer 2, can have almost any shape, and need not be so configured: so that it can be closed quickly to enable the creation of a cavity.

If the channel structures described above are also arranged below the transverse channel structures extending in the substructure, as is indicated in fig. 27, it is possible via these channel structures to rapidly distribute an etching medium, for example gaseous (for example HF vapour), laterally over the surface and also to facilitate the removal of the silicon dioxide layer in the substructure within the transverse channel structures 12a.. 12n, as can be seen in fig. 28. This advantageously additionally provides a further enlargement of the passage cross section.

In all the variants shown, the etch stop layer 3, which is electrically insulating and etch-resistant with respect to the etching medium used for removing the sacrificial layer, and the lateral etch stop delimitations 13a.. 13n in the substructure serve to enable the etching channel used for removing the sacrificial layer to be guided to any location within the cavity region.

The proposed micromechanical component 100 produced by means of the proposed method may be, for example, a capacitive pressure sensor. However, other embodiments are also conceivable, such as microphones, piezoresistive pressure sensors, etc.

Fig. 29 to 31 show top views of different embodiments of the proposed micromechanical component 100. It can be seen that starting from the vertical etching channels 11, a plurality of lateral etching channels 12a.. 12n can be formed, in the region or course of which via etching channels 3a1...3an can be provided at defined locations through the etch stop layer 3 into the cavity region 7a, by means of which via etching channels sacrificial layer etching can take place from below in the cavity region 7 a.

Fig. 32 shows a schematic flow of a method for producing the proposed micromechanical component 100.

In step 200, a cavity 20 is constructed below the cover element 10.

In step 210, at least one vertical etching channel 11 arranged outside the anchoring structure of the cover element 10 is formed, wherein the formation of the cavity 20 is carried out by means of at least one lateral etching channel 12a.. 12n, which is arranged below the etch stop layer 3 and below the cavity 20, starting from the vertical etching channel 11 and is arranged between the etch stop layer 3 and the silicon substrate 1, and at least one via etching channel 3a1...3 an.

Claims

1. A micromechanical component (100) having:

-a covering element (10);

-a cavity (20) arranged below the covering element (10);

-at least one vertical etched channel (11) arranged outside the anchoring structure of the covering element (10);

-at least one lateral etching channel (12a.. 12n) arranged below the etch stop layer (3) and below the cavity (20) and arranged between the etch stop layer (3) and the silicon substrate (1) starting from the at least one vertical etching channel (11); and

-at least one via-etched channel (3a1...3an) configured between the at least one lateral etched channel (12a.. 12n) and the cavity (20).

2. Micromechanical component (100) according to claim 1, characterized in that the at least one vertical etched channel (11) is configured in the form of a slit or a tube.

3. Micromechanical component (100) according to claim 1 or 2, characterized in that at least one electrically conductive limiting element (13a.. 13n) and/or an electrically insulating limiting element (13a.. 13n) which laterally limits the at least one lateral etching channel (12a.. 12n) is/are formed in the first silicon dioxide layer (2).

4. Micromechanical component (100) according to any of the preceding claims, characterized in that the at least one vertical etched channel (11) is configured to be electrically conductively connected to the cover element (10) or electrically insulated from the cover element (10).

5. Micromechanical component (100) according to any of the preceding claims, characterized in that the at least one vertical etching channel (11) is configured to be electrically conductively connected to the at least one electrically conductive limiting element (13a.. 13n) or electrically insulated from the at least one electrically conductive limiting element (13a.. 13 n).

6. Micromechanical component (100) according to claim 4 or 5, characterized in that the at least one lateral etching channel (12a.. 12n) is delimited in the first silicon dioxide layer (2) by at least one electrically conductive and/or electrically insulating delimiting element (13a.. 13 n).

7. Micromechanical component (100) according to any of the preceding claims, characterized in that the at least one lateral etching channel (12a.. 12n) is at least partially configured within the substrate (1) or at least partially above the substrate (1).

8. Micromechanical component (100) according to any of the preceding claims, characterized in that starting from the at least one vertical etching channel (11) a plurality of etching channels (12a.. 12n) are configured.

9. Micromechanical component (100) according to claim 8, characterized in that the plurality of lateral etched channels (12a.. 12n) is configured as a mesh and/or parallel.

10. A method for producing a micromechanical component (100), having the following steps:

-constructing a cavity (20) below the covering element (10);

-structuring at least one vertical etched channel (11) arranged outside the anchoring structure of the covering element (10); wherein the structuring of the cavity (20) is performed by means of at least one lateral etching channel (12a … 12n) and by means of at least one via etching channel (3a1 … 3an) opening into the cavity (20), the at least one lateral etching channel (12a … 12n) being arranged below the etch stop layer (3) and below the cavity (20) and being arranged between the etch stop layer (3) and the silicon substrate (1) proceeding from the vertical etching channel (11).