CN112520687A - Method for producing a micromechanical system and micromechanical system - Google Patents

Method for producing a micromechanical system and micromechanical system Download PDF

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Publication number
CN112520687A
CN112520687A CN202010984667.5A CN202010984667A CN112520687A CN 112520687 A CN112520687 A CN 112520687A CN 202010984667 A CN202010984667 A CN 202010984667A CN 112520687 A CN112520687 A CN 112520687A
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Prior art keywords
etching
micromechanical
functional layer
trenches
etching trenches
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J·赖因穆特
T·弗里德里希
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
    • B81C1/00444—Surface micromachining, i.e. structuring layers on the substrate
    • B81C1/00468—Releasing structures
    • B81C1/00476—Releasing structures removing a sacrificial layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00349—Creating layers of material on a substrate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
    • B81B3/0064—Constitution or structural means for improving or controlling the physical properties of a device
    • B81B3/0067—Mechanical properties
    • B81B3/007—For controlling stiffness, e.g. ribs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
    • B81C1/00523—Etching material
    • B81C1/00531—Dry etching
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
    • B81C1/00523—Etching material
    • B81C1/00539—Wet etching
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
    • G01L1/142—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors
    • G01L1/148—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors using semiconductive material, e.g. silicon
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/12—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance, i.e. electric circuits therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00—Specific applications of microelectromechanical systems
    • B81B2201/02—Sensors
    • B81B2201/0264—Pressure sensors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2203/00—Basic microelectromechanical structures
    • B81B2203/01—Suspended structures, i.e. structures allowing a movement
    • B81B2203/0127—Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C2201/00—Manufacture or treatment of microstructural devices or systems
    • B81C2201/01—Manufacture or treatment of microstructural devices or systems in or on a substrate
    • B81C2201/0101—Shaping material; Structuring the bulk substrate or layers on the substrate; Film patterning
    • B81C2201/0128—Processes for removing material
    • B81C2201/013—Etching
    • B81C2201/0133—Wet etching

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Micromachines (AREA)

Abstract

The invention provides a manufacturing method for a micromechanical system and the micromechanical system. The method comprises the following steps: applying a first micromechanical functional layer on a substrate; in a first anisotropic etching step, a plurality of two-dimensionally arranged, spaced-apart, elongated etching trenches are formed in a first region of the first micromechanical functional layer, wherein the etching trenches are spaced apart from adjacent etching trenches at one or both longitudinal ends by a break region to a first etching depth which is less than the thickness of the first micromechanical functional layer; and in a subsequent isotropic etching step, the etching trenches are expanded to a second etching depth which is greater than the first etching depth and less than the thickness of the first micromechanical functional layer, wherein the etching trenches are expanded within the first micromechanical functional layer and an interruption region is etched underneath the etching trenches, such that adjacent etching trenches are connected to one another within the first micromechanical functional layer below the interruption region, wherein the interruption region remains on the upper side of the first micromechanical functional layer.

Description

Method for producing a micromechanical system and micromechanical system
Technical Field
The invention relates to a method for producing a micromechanical system and to a micromechanical system.
Background
Although applicable to any micromechanical system, the present invention and the background on which the present invention is based are explained with respect to micromechanical pressure sensors manufactured in silicon technology.
DE 102011080978 a1 discloses a method for producing micromechanical structures, by means of which the topography of a MEMS functional layer can be freely structured. This method is typically used to arrange a plurality of MEMS functional layers on top of each other. In this case, cavities are produced in the process in the region of the removed MEMS functional layer. These cavities can be used intentionally, for example as etching channels, to locally accelerate the sacrificial layer etching often used in MEMS processes and thereby locally modify the lower etching in a controlled manner.
A method in which, for example, these etched channels can be used and are also required for the function of the component is a capacitive pressure sensor.
Fig. 8a), 8b) show an example of a micromechanical system in the form of a capacitive micromechanical pressure sensor for explaining the problem on which the invention is based.
In fig. 8a), reference sign S denotes a substrate, for example a silicon substrate, on which a first insulating layer I1 and a second insulating layer I2 located above the first insulating layer are applied. The first insulating layer I1 is made of silicon dioxide, for example, and the second insulating layer I2 is made of silicon nitride.
A thin conductor track layer L, for example made of polysilicon, is applied to the second insulating layer I2 and is structured in such a way that it forms the first electrode E1.
A first micromechanical functional layer F1 made of polysilicon and a second micromechanical functional layer F2 made of polysilicon are applied and structured above the conductor track layer L. In particular, a membrane region M is structured out of the second micromechanical functional layer F2, which membrane region spans the cavity K.
On the underside of the membrane, a functional element 1 is present, which is structured from the first micromechanical functional layer F1. This functional element 1 is used on the one hand as a reinforcing element for the membrane M and on the other hand as a second electrode E2 or counter electrode for the electrode E1 and also serves, in terms of its function, during the production process, to accelerate the etching of the sacrificial layer in the region where the sacrificial layer is to be removed. In particular, these (not shown) sacrificial layers are located in the region between the first electrode E1 and the second electrode E2.
In order to accelerate the sacrificial layer etching process, etching channels are provided on the underside of the functional element 1, which etching channels run parallel to one another in a direction parallel to the drawing plane.
In this regard, fig. 8a) shows a cross section of the consolidated area, and fig. 8b) shows a cross section of the etched channel. Thus, the reinforcement area may cause reinforcement in only one direction, but not in a direction perpendicular to that direction. Furthermore, it is not possible to interconnect the etching channels running through the functional element 1, which would impair the stiffening properties.
Disclosure of Invention
The invention relates to a method for producing a micromechanical system and to a micromechanical system.
The invention is based on the idea of realizing an etched trench structure in which all etched trenches are fluidically connected to one another by means of an at least two-stage etching method, wherein the two-dimensional mechanical reinforcement is realized by bridge-shaped interruption regions of the etched trenches, which interruption regions are produced from micromechanical functional layers. Such an etched trench structure can be realized in particular by a combination of a first anisotropic etching step and a subsequent isotropic etching step, wherein the isotropic etching step causes a lower etching of the interruption region, so that the etched trenches are interconnected inside the micromechanical functional layer in the lower etching region, wherein the mechanically stable interruption region remains on the upper side of the micromechanical functional layer. The production method according to the invention can also be scaled for thicker functional layers (skalieren) and does not suffer from limitations in terms of the thickness of the functional layer.
Such a micromechanical system with a two-dimensional etched trench structure can be used, for example, as an etching channel system for guiding an etching fluid in a sacrificial layer etching step, but is not limited thereto. Applications in microfluidic systems or other micromechanical systems are also conceivable.
The features listed below relate to advantageous embodiments and improvements of the subject matter of the invention.
According to a preferred embodiment, the etched trench has a first plurality of first etched trenches and a second plurality of second etched trenches, wherein the interruption region has a first plurality of first interruption regions and a second plurality of second interruption regions. In a first anisotropic etching step and a subsequent isotropic etching step, a first plurality of first etching trenches is formed running in a first longitudinal direction and a second plurality of second etching trenches is formed running in a second longitudinal direction. The first etching trenches and the second etching trenches are arranged alternately in each case in the first longitudinal direction and the second etching trenches are arranged in rows with respect to one another in the second longitudinal direction, wherein first interruption regions are provided in each case between the first and second etching trenches in the first longitudinal direction, and wherein second interruption regions are provided in each case between the second etching trenches in the second longitudinal direction.
According to a further preferred development, the first longitudinal direction is arranged substantially perpendicularly to the second longitudinal direction. This enables the formation of an etched trench structure having a rectangular pattern.
According to a further preferred embodiment, the first sacrificial layer is applied to the substrate before the first micromechanical functional layer is applied, wherein the isotropic etching step is followed by etching trenches in the second isotropic etching step up to a third etching depth which extends over the entire depth of the first micromechanical functional layer and exposes the first sacrificial layer, wherein the interruption region remains on the upper side of the first micromechanical functional layer, and wherein a further interruption region is formed on the lower side of the first micromechanical functional layer, said further interruption region being oriented in the depth direction of the first micromechanical functional layer towards said interruption region. The production method according to the invention is particularly well suited for thin sacrificial layers underneath the micromechanical functional layer, in particular when using a third anisotropic etching step, in order to produce a particularly large capacitance between the functional layer and the base.
According to a further preferred embodiment, a further etching trench is formed in the periphery of the first region (Peripherie) by means of the first and second anisotropic etching steps and the isotropic etching step.
According to a further preferred embodiment, the further trenches have a third plurality of trenches which surround the first region in an annular closed manner. This forms a first region of the first micromechanical functional layer that is spaced apart and free-floating (freischwebende).
According to a further preferred embodiment, a second sacrificial layer is formed which closes the etching trench and the further etching trench at the top side and covers the interior, wherein the respective cavity remains in the expanded region of the etching trench. Such cavities accelerate the subsequent sacrificial layer etching step.
According to a further preferred embodiment, a first through-opening is formed in the second sacrificial layer in the vicinity of the first region, said first through-opening locally exposing the first mechanical functional layer located therebelow.
According to a further preferred development, in a further isotropic etching step, the first mechanical functional layer located below the first through opening is locally removed, wherein the second sacrificial layer functions as an etch stop. This enables the removal of a defined region of the first micromechanical functional layer.
According to a further preferred embodiment, a third sacrificial layer is formed, which closes the first through opening.
According to a further preferred embodiment, one or more second through openings are formed in the first region, which second through openings partially expose the first mechanical functional layer located thereunder, wherein a second micromechanical functional layer is formed and structured, which second micromechanical functional layer is connected to the first micromechanical functional layer within the second through openings. This enables the formation of a suspension of the first micromechanical functional layer at the second micromechanical functional layer.
According to a further preferred development, the first, second and third sacrificial layers are removed by a sacrificial layer etching step using the etching trenches and/or the further etching trenches as etching channels. The etching channels do not cause restrictions in the mechanical properties of the first micromechanical functional layer. In particular, the etched trenches of the continuous interconnect do not cause mechanical separation of the micromechanical functional layers. In the case of etching trenches with a larger diameter as etching channels, it is also possible to apply etching methods with the aid of liquid media, which were not possible hitherto. Various etching methods based on liquid media are significantly more cost-effective and also often provide higher or better selectivity with respect to the etch stop layer.
Drawings
Further features and advantages of the invention are explained below with reference to the drawings.
Fig. 1a) -1c) to fig. 7a) -7c) show successive process stages of an embodiment of the production method according to the invention for micromechanical systems; the partial images a) each show a top view, the partial images B) each show a section along the line a-a 'in the partial image a), and the partial images c) each show a section along the line B-B' in the partial image a).
Fig. 8a), 8b) show an example of a micromechanical system in the form of a capacitive micromechanical pressure sensor for explaining the problem on which the present invention is based.
Detailed Description
In the drawings, like reference numbers indicate identical or functionally identical elements.
Fig. 1a) -1c) to fig. 7a) -7c) show successive process stages of an embodiment of the production method according to the invention for micromechanical systems; the partial images a) each show a top view, the partial images B) each show a section along the line a-a 'in the partial image a), and the partial images c) each show a section along the line B-B' in the partial image a).
In fig. 1a) -1c), reference sign S denotes a substrate, for example a silicon substrate. Alternatively (not shown), different functional and/or insulating layers can be grown and structured on the substrate S in a pretreatment (see fig. 8a), 8 b)).
A first sacrificial layer O is grown and structured on a substrate S, for example formed of silicon dioxide. The first sacrificial layer O may also be structured in order to produce a substrate contact or contact plane with respect to one of the optional functional layers. In the present example, a first micromechanical functional layer F1 made of conductively doped polysilicon or a similar conductively capable material is formed on the first sacrificial layer O.
A plurality of two-dimensionally arranged, spaced-apart, elongated etching trenches K2, K3 are then formed in a first anisotropic etching step in a first region B1 of the first micromechanical functional layer F1. The etching trenches K2, K3 may be oriented substantially perpendicular to each other. Alternatively, the etched trenches may also be arranged parallel or offset parallel. Alternatively, the etched trenches K2 and K3 may have different widths and/or lengths in all embodiments.
The etching trenches K2, K3 are spaced apart at one or both longitudinal ends from the adjacent etching trenches K2, K3 by respective interruption regions U1, U2 formed by the first micromechanical functional layer F1.
The first anisotropic etching step is carried out to a first etching depth, which is smaller than the thickness of the first micromechanical functional layer F1, and is performed, for example, using a process using SF6(sulfur hexafluoride) in the case of a plasma process. A passivation layer may be deposited on the sidewalls of the etched trenches K2, K3 in the final stage of the first anisotropic etching step.
In a subsequent isotropic etching step, for example, also using SF6In the case of the plasma method (sulfur hexafluoride), the trenches K2, K3 are extended to a second etching depth which is greater than the first etching depth and less than the thickness of the first micromechanical functional layer F1. The isotropic etching step is controlled in such a way that the lower lateral etching in this step corresponds to at least half the width of the interruption regions U1, U2.
In this case, the etched trenches K2, K3 are widened inside the first micromechanical functional layer F1 and the interruption regions U1, U2 are etched underneath in such a way that adjacent etched trenches K2, K3 are connected to one another inside the first micromechanical functional layer F1 below the interruption regions U1, U2 by widening, wherein the interruption regions U1, U2 remain on the upper side of the first micromechanical functional layer F1 and form a mechanical stabilization or reinforcement of the structure.
The etching trenches K2, K3 have in the present example a first majority of first etching trenches K2 and a second majority of second etching trenches K3, and the interruption regions U1, U2 have a first majority of first interruption regions U1 and a second majority of second interruption regions U2.
In a first anisotropic etching step and a subsequent isotropic etching step, a first plurality of first etching trenches K2 is formed running in the first longitudinal direction x and a second plurality of second etching trenches K3 is formed running in the second longitudinal direction y.
The first etching trenches K2 and the second etching trenches K3 are arranged alternately in the first longitudinal direction x, respectively, wherein the second etching trenches K3 are arranged in rows with respect to one another in the second longitudinal direction y.
First interruption regions U1 are respectively arranged in the first longitudinal direction x between the first and second etching trenches K2, K3, wherein second interruption regions U2 are respectively arranged in the second longitudinal direction y between the second etching trenches K3.
In the present example, the first longitudinal direction x is arranged substantially perpendicular to the second longitudinal direction y.
Furthermore, for example, in the periphery of the first region B1, further trenches K0, K1, K1 ' are formed by a first and a second anisotropic etching step and an isotropic etching step, wherein the further trenches K0, K1, K1 ' have a third plurality of trenches K1, K1 ' which surround the first region B1 in an annular closed manner and which are connected to the first and second trenches K2, K3 after the two etching steps.
Therefore, according to fig. 1a) -1c), there are micromechanical systems with mechanically stable etched trench structures interconnected in the region B1, for which there are different application possibilities.
In the present example, according to fig. 2a) -2 c), a second anisotropic etching step is carried out following the isotropic etching step, wherein the etching trenches K0, K1, K1', K2, K3 are etched up to a third etching depth which is the same as the third etching depthThe degree extends over the entire depth of the first micromechanical functional layer F1, for example, also in use with SF6In the case of the plasma method (sulfur hexafluoride), the first micromechanical functional layer optionally has an additional passivation layer in the region above the etched trenches K0, K1, K1', K2, K3.
Subsequently, the trenches K0, K1, K1', K2, K3 are etched such that the first sacrificial layer O is exposed, wherein the interruption regions U1, U2 remain on the upper side of the first micromechanical functional layer F1, and wherein further interruption regions U3 are formed on the lower side of the first micromechanical functional layer F1, which are oriented symmetrically with respect to the interruption regions U1, U2 in the depth direction of the first micromechanical functional layer F1.
Furthermore, with reference to fig. 3a) to 3c), a second sacrificial layer O ' is formed from silicon dioxide, which closes the first and second etching trenches K2, K3 and the further etching trenches K0, K1, K1 ' on the upper side and covers them in the interior, wherein a cavity HZ remains in the expanded region of the etching trenches K0, K1, K1 ', K2, K3, which can be used as an etching channel in a subsequent sacrificial layer etching process.
Further, referring to fig. 4a) to 4c), in the periphery of the first region B1, the second sacrificial layer O' has a first through portion D that partially exposes the first mechanical functional layer F1 located therebelow.
In a further isotropic etching step, the first mechanically functional layer F1 is locally removed below the first through going portion D, wherein the second sacrificial layer O' acts laterally as an etch stop and the first sacrificial layer O acts vertically as an etch stop.
According to fig. 5a) -5 c), a third sacrificial layer O ″ is constructed from silicon dioxide, which closes the first through-opening D.
One or more second through holes D 'are formed in the first region B1, and the first mechanical functional layer F1 located therebelow is partially exposed through the second through hole D'.
Then, a second micromechanical functional layer F2, which is connected to the first micromechanical functional layer F1 within the second through opening D2, is formed from polycrystalline silicon and is structured.
After further optional steps, according to fig. 7a) -7c), the first, second and third sacrificial layers O, O ', O "are removed by a sacrificial layer etching step using the first and second etch trenches K2, K3 and the further etch trenches K0, K1, K1' as etch channels.
In the sacrificial layer etching step, the etching front spreads more rapidly in the cavity HR of the first and second etching trenches K2, K3 and the further etching trenches K0, K1, K1' than in the solid sacrificial layer material. Preferably, an etching method using liquid HF (hydrogen fluoride) or a solution containing HF is applied in the sacrificial layer etching step.
Additional optional steps may follow. For example, the cavity created by the sacrificial layer etching step can be hermetically closed.
When using the micromechanical system in a pressure sensor, according to fig. 7B) the region of the second micromechanical functional layer F2 is a membrane and the region B1 of the first micromechanical functional layer F1 is a functional element 1' (see fig. 8a), 8B)), which serves as an electrode and a stiffening element. Particularly advantageously, the reinforcement acts two-dimensionally here, i.e. in the x and y longitudinal directions.
Although the invention has been described above with reference to preferred embodiments, the invention is not limited thereto but can be varied in many ways.
In particular, the invention is not limited to the exemplary proposed layer materials. The invention is also not only suitable for the exemplary pressure sensors mentioned, but in principle for all micromechanical sensors or actuators in which two electrically conductive functional regions are suspended on a substrate in a mechanically connected but electrically isolated manner.
In a variant, the first anisotropic etching step can also be divided into two different regions by two etchings, for example, by means of a lacquer mask. In the first region, the anisotropic etching does not take place over the entire depth of the functional layer. In the second region, the etching is performed over the entire depth of the functional layer. In the second region, no under-etching of the side faces is produced in a subsequent step. This action can be used to define areas where etching proceeds more slowly, or where vertical trenches are desired, for example to create capacitive drive or sense structures or to create very precisely defined springs.
The concept according to the invention also brings new design freedom for packaged acceleration or tacho sensors or resonators. In principle, it is also possible to use new closing methods which allow only a small number of openings, such as laser repackaging methods. It has hitherto been necessary to provide a very large number of closely spaced etching inlets in a very large number of process flows for the etching of sacrificial layers, which are difficult to close because of the large number of inlets.

Claims (15)

1. Manufacturing method for a micromechanical system, having the following steps:
applying a first micromechanical functional layer (F1) on a substrate (S);
forming a plurality of two-dimensionally arranged, spaced-apart, elongated etching trenches (K2, K3) in a first region (B1) of the first micromechanical functional layer (F1) in a first anisotropic etching step, wherein the etching trenches (K2, K3) are spaced apart from adjacent etching trenches (K2, K3) at one or both longitudinal ends by respective interruption regions (U1, U2) formed by the first micromechanical functional layer (F1), the etching trenches being carried out to a first etching depth which is less than the thickness of the first micromechanical functional layer (F1); and is
In a subsequent isotropic etching step, the etching trenches (K2, K3) are expanded to a second etching depth which is greater than the first etching depth and less than the thickness of the first micromechanical functional layer (F1), wherein the etching trenches (K2, K3) are expanded inside the first micromechanical functional layer (F1) and the interruption regions (U1, U2) are underetched such that adjacent etching trenches (K2, K3) are connected to one another inside the first functional layer (F1) below the interruption regions (U1, U2), wherein the interruption regions (U1, U2) remain at the upper side of the first micromechanical functional layer (F1).
2. The manufacturing method for a micromechanical system according to claim 1,
the etching trenches (K2, K3) having a first plurality of first etching trenches (K2) and a second plurality of second etching trenches (K3);
the interruption regions (U1, U2) having a first interruption region (U1) of a first majority and a second interruption region (U2) of a second majority;
in the first anisotropic etching step and the subsequent isotropic etching step, a first plurality of first etching trenches (K2) is formed running in a first longitudinal direction (x), and a second plurality of second etching trenches (K3) is formed running in a second longitudinal direction (y);
wherein first (K2) and second (K3) etching trenches, respectively, are alternately arranged in the first longitudinal direction (x), and the second etching trenches (K3) are arranged in rows with respect to one another in the second longitudinal direction (y);
wherein the first interruption region (U1) is provided between the first and second etching trenches (K2, K3) respectively in the first longitudinal direction (x);
wherein the second interruption regions (U2) are respectively provided between the second etching trenches (K3) in the second longitudinal direction (y).
3. Method for manufacturing a micromechanical system according to claim 2, wherein said first longitudinal direction (x) is arranged substantially perpendicular to said second longitudinal direction (y).
4. Method for manufacturing a micromechanical system according to any of the preceding claims, wherein a first sacrificial layer (O) is applied on the substrate (S) before the application of the first micromechanical functional layer (F1), wherein the etching trench (K2, K3) is etched in a second anisotropic etching step immediately following the isotropic etching step up to a third etching depth which extends over the entire depth of the first micromechanical functional layer (F1), and the etching trench (K2, K3) exposes the first sacrificial layer (O), wherein the interruption region (U1, U2) remains at the upper side of the first micromechanical functional layer (F1), wherein a further interruption region (U3) is formed at the lower side of the first micromechanical functional layer (F1), which further interruption region faces the interruption region (U1) in the depth direction of the first micromechanical functional layer (F1), U2).
5. Manufacturing method for micromechanical systems according to claim 4, wherein further etching trenches (K0, K1, K1') are formed in the periphery of the first region (B1) by means of the first and second anisotropic etching steps and the isotropic etching step.
6. Manufacturing method for micromechanical systems according to claim 5, wherein the further etching trenches (K0, K1, K1 ') have a third majority of etching trenches (K1, K1') which annularly enclose around the first region (B1).
7. Manufacturing method for micromechanical systems according to claim 6, wherein a second sacrificial layer (O ') is constructed which closes the etching trenches (K2, K3) and the further etching trenches (K0, K1, K1 ') at the upper side and covers in the interior, wherein the respective cavities (HZ) remain in the flared regions of the etching trenches (K0, K1, K1 ', K2, K3).
8. The manufacturing method for a micromechanical system according to claim 7, wherein a first through-hole (D) is configured in the second sacrificial layer (O') in the periphery of the first region (B1), said first through-hole locally exposing the first mechanical functional layer (F1) located thereunder.
9. Method for manufacturing a micromechanical system according to claim 8, wherein in a further isotropic etching step the first mechanical functional layer (F1) underlying the first through-going portion (D) is locally removed, wherein the second sacrificial layer (O') functions as an etch stop.
10. Method for manufacturing a micromechanical system according to claim 9, wherein a third sacrificial layer (O ") is configured, which closes the first through-going portion (D).
11. The production method for micromechanical systems according to claim 10, wherein one or more second through openings (D') are formed in the first region (B1), which partially expose the first mechanically functional layer (F1) located thereunder, wherein a second micromechanical functional layer (F2) is formed and structured, which is connected to the first micromechanical functional layer (F1) within the second through opening (D2).
12. Manufacturing method for micromechanical systems according to claim 11, wherein the first, second and third sacrificial layers (O, O ', O ") are removed by a sacrificial layer etching step using the etching trenches (K2, K3) and/or the further etching trenches (K0, K1, K1') as etching channels.
13. A micromechanical system having:
a first micromechanical functional layer (F1) applied on the substrate (S);
a plurality of two-dimensionally arranged, spaced-apart, elongated etching trenches (K2, K3) in a first region (B1) of the first micromechanical functional layer (F1), wherein the etching trenches (K2, K3) are spaced apart from adjacent etching trenches (K2, K3) at one or both longitudinal ends on the upper side of the first micromechanical functional layer (F1) by respective interruption regions (U1, U2) formed by the first micromechanical functional layer (F1);
wherein the etching trenches (K2, K3) are widened in the interior of the first micromechanical functional layer (F1) and the interruption regions (U1, U2) are underetched, so that adjacent etching trenches (K2, K3) are connected to one another in the interior of the first micromechanical functional layer (F1) below the interruption regions (U1, U2).
14. The micromechanical system of claim 13,
the etching trenches (K2, K3) having a first plurality of first etching trenches (K2) and a second plurality of second etching trenches (K3);
the interruption regions (U1, U2) having a first interruption region (U1) of a first majority and a second interruption region (U2) of a second majority;
the first plurality of first etching grooves (K2) is formed running in a first longitudinal direction (x), and the second plurality of second etching grooves (K3) is formed running in a second longitudinal direction (y);
wherein first (K2) and second (K3) etching trenches are arranged alternately in the first longitudinal direction (x) and in rows with one another in the second longitudinal direction (y);
wherein the first interruption region (U1) is provided between the first and second etching trenches (K2, K3) respectively in the first longitudinal direction (x);
wherein the second interruption regions (U2) are respectively provided between the second etching trenches (K3) in the second longitudinal direction (y).
15. Micromechanical system according to claim 13 or 14, wherein the first region (B1) is at least locally connected with a second micromechanical functional layer (F2) arranged above it and is arranged freely floating above the substrate (S).
CN202010984667.5A 2019-09-19 2020-09-18 Method for producing a micromechanical system and micromechanical system Pending CN112520687A (en)

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