DE102018220422A1 - Actuation device for a micromechanical component, micromechanical component and method for producing a micromechanical component - Google Patents

Abstract

The invention relates to an actuation device (1) for a micromechanical component (2) comprising a suspension frame (3); a plurality of bending beams (4) with a spring material (FM), the bending beams (4) each being mechanically connected to the suspension frame (3) and extending laterally therefrom; a plurality of actuator devices (4a), the actuator devices (4a) being mechanically connected to the bending beams (4); a ring element (5) or frame element which is mechanically connected to the bending beams (4) and is laterally spaced from the suspension frame (3) and has a lower flexibility than the bending beams (4); a plurality of spring elements (6) which are mechanically connected to the ring element (5) and laterally extend away from the ring element (5) on a side facing away from the suspension frame (3); and a central segment (7) to be moved, the spring elements (6) mechanically connecting the central segment (7) to the ring element (5).

Description

The present invention relates to an actuation device for a micromechanical component, a micromechanical component and a method for producing a micromechanical component.

State of the art

With regard to applications of movable micromechanical components, for example mirrors, a movable and as planar (mirror) surface as possible is an important prerequisite for good performance properties for many applications, with an internal mechanical tension being as low as possible. Usually, a (mirror) functional element can be made very thick and thus rigid. A soft membrane can be arranged between such a rigid element and its outer suspension, in order nevertheless to be able to achieve the greatest possible deflection with, for example, a piezo actuator with the lowest possible voltages applied.

In the US 9,250,418 B2 describes a Fabry-Perot interferometer with piezo actuators which can move a mirror, the mirror being attached to a frame and the actuators connecting the frame to the mirror.

Disclosure of the invention

The present invention provides an actuation device for a micromechanical component according to claim 1, a micromechanical component according to claim 7 and a method for producing a micromechanical component according to claim 11.

Preferred developments are the subject of the dependent claims.

Advantages of the invention

The idea on which the present invention is based is to specify an actuation device for a micromechanical component, a micromechanical component and a method for producing a micromechanical component which are distinguished by an improved possibility of movement, wherein a planar deflection of a central segment can be improved and the vibrations - And gravitational sensitivity can be reduced. The MEMS component can be made very small.

According to the invention, the actuation device for a micromechanical component comprises a suspension frame; a plurality of bending beams with a spring material, the bending beams each being mechanically connected to the suspension frame and extending laterally therefrom; a plurality of actuators, the actuators being mechanically connected to the bending beams; a ring element or frame element which is mechanically connected to the bending beams and is laterally spaced from the suspension frame and has a lower flexibility than the bending beams; a plurality of spring elements which are mechanically connected to the ring element or frame element and laterally extend away from the ring element or frame element on a side facing away from the suspension frame; and a central segment to be moved, the spring elements mechanically connecting the central segment to the ring element or frame element.

Such an embodiment with a ring element / frame element and a central segment can advantageously enable maximum planarity of the central element without having to accept excessive vibration and gravity sensitivity of the actuation device and of the entire micromechanical component. Usually, the thickness is increased in order to achieve the highest possible planarity of the central element in order to increase the bending stiffness. An increase in thickness is accompanied by an increase in mass, which would reduce the natural frequency of the system, which is why it can then have an increased sensitivity to vibration and gravity.

The ring element or frame element can be understood to mean an essentially planar, self-contained shape or a polygon, which can be circular but can also include other shapes, for example square.

In general, small layer thicknesses can always be formed in the case of most subcomponents in their layers, as a result of which parasitic absorption of light can advantageously be reduced. If the micromechanical component is shaped as a Fabry-Perot interferometer device, light absorption in the substrate can be reduced by small substrate thicknesses. Such a MEMS component can advantageously be formed on a very small scale and include a mirror surface on the central segment of high planarity, that is, the curvature of a mirror device on the central segment can be reduced. Furthermore, a low actuation voltage can be sufficient to move the central segment and the movement of the central segment can nevertheless comprise a higher natural frequency than would be the case with those central segments which would have to be increased in thickness to increase rigidity. The spring elements can furthermore an improved compensation of any tilting of the central segment, for example in the Fabry-Perot interferometer, can be achieved, with which an achievable optical resolution of the filter effect can be increased.

The suspension frame can be applied to a substrate or can itself comprise a substrate, in which case the bending beams can then be attached to the substrate. The actuators can each be assigned to a separate bending beam.

The ring element can connect a plurality of bending beams to one another.

The ring element can have incisions in the radial direction on both sides, which can facilitate expansion upon actuation.

The actuator or actuators can comprise at least one electrostatic and / or piezoelectric (bending) actuator, both embodiments advantageously being able to require only little power for actuation. The bending beams can have actuators on both the end of the suspension frame and the end of the ring element, which can enable actuation in two directions.

According to a preferred embodiment of the actuation device, the central segment comprises a planar extension and can be moved or rotated perpendicular to the planar extension by means of the actuators via the bending beams and via the spring elements.

Such an arrangement is advantageously suitable for an interferometer if the central segment comprises a mirror.

According to a preferred embodiment of the actuation device, the bending beams and the spring elements comprise the same spring material.

According to a preferred embodiment of the actuation device, the ring element and the central segment comprise the same material.

By means of the reinforcement layer, the ring element and the central segment can be made more rigid than the spring area and the area of the bending beams.

According to a preferred embodiment of the actuation device, the ring element and the central segment comprise the same spring material as the bending beams and the spring elements and a reinforcing layer.

The bending beams and the spring elements can advantageously have essentially the same thickness.

Furthermore, the central segment and the ring element can be rigid and have essentially the same thickness.

According to a preferred embodiment of the actuation device, the central segment comprises a clamping frame connected to the spring elements and an inner membrane.

The stenter frame can represent an outer edge of the central segment as a ring and can tension a membrane in the inner region. The membrane can itself be a reflective element or it can be arranged on the membrane.

According to the invention, the micromechanical component comprises an actuation device according to the invention; and a first substrate, wherein the suspension frame is attached to the first substrate or the first substrate itself represents the suspension frame and laterally rotates the bending beams.

According to a preferred embodiment of the micromechanical component, the actuation element advantageously comprises a first mirror device.

According to a preferred embodiment of the micromechanical component, the latter comprises a second substrate with a second mirror device, the second substrate being arranged on the first substrate and the first mirror device being arranged opposite the second mirror device.

The micromechanical component can be designed with the two mirror devices as a Fabry-Perot interferometer.

According to a preferred embodiment of the micromechanical component, it is designed as a spectrometer device and comprises a light-sensitive detector device which is arranged downstream of the first mirror device and the second mirror device in a light emission direction.

The detector device can detect light of specific wavelengths which is transmitted through the resonator, which the two mirror devices can represent for specific distances.

According to the invention, a first substrate is provided in the method for producing a micromechanical component; a Applying an insulator layer on the first substrate and structuring the insulator layer into areas for a spring trench which laterally runs around a central segment and an actuator trench which runs around the spring trench at a certain distance and runs around a ring element between the spring trench and the actuator trench; applying a spring material on the first substrate and on the insulator layer and a mirror material for a first mirror device on the central segment; introducing a spring trench and an actuator trench into the first substrate up to the insulator layer; and removing the insulator layer in the spring trench and in the actuator trench.

The method can also be characterized by the features already mentioned in connection with the actuation device and the micromechanical component and their advantages, and vice versa.

According to a preferred embodiment of the method, a piezo actuator layer is applied to the spring material above the actuator trench and a second substrate is provided with a second mirror device and the second substrate is arranged above the first substrate so that the second mirror device is opposite the first mirror device and is provided of a base substrate, which comprises a cavity over which the first substrate is arranged.

The actuator trench and the spring trench can already be marked (structured) as areas in the substrate, for example exposed before an actual removal of the substrate material takes place, before the further elements (spring material, actuator layers, etc.) are formed over these areas. Nevertheless, in the context of this description, one can already speak of actuator trenches and spring trenches; in fact, for the time being, these can be the areas provided for these trenches.

The order of the process steps can also differ from the order mentioned. When the mirror material is applied to the central segment, the bond connections and supply lines can also be applied; alternatively, the supply lines can also be arranged in previous steps (before the spring material is applied). The arrangement of the first substrate on the base substrate can take place before or after the connection of the first and the second substrate. Before the second substrate is applied, the spring material can be structured into the shape of the spring elements above the spring trench. Subsequent, for example after all substrates have been connected, leads or bond pads can be exposed, for example by sawing.

Alternatively, an SOI substrate (silicon on insulator) can be used in an analogous manner for the first substrate, which already comprises an insulator and a spring material layer

Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

Figure list

The present invention is explained in more detail below with reference to the embodiment shown in the schematic figures of the drawing.

• 1 eine schematische Ansicht einer Aktuationseinrichtung in einem mikromechanischen Bauelement gemäß eines Ausführungsbeispiels der vorliegenden Erfindung;
• 2 eine schematische Ansicht einer Aktuationseinrichtung gemäß eines Ausführungsbeispiels der vorliegenden Erfindung;
• 3 eine schematische Seitenansicht eines mikromechanischen Bauelements gemäß eines Ausführungsbeispiels der vorliegenden Erfindung; und
• 4 eine schematische Draufsicht eines mikromechanischen Bauelements gemäß eines Ausführungsbeispiels der vorliegenden Erfindung; und
• 5 eine schematische Blockdarstellung eines Verfahrens zur Herstellung eines mikromechanischen Bauelements gemäß eines Ausführungsbeispiels der vorliegenden Erfindung.

Show it:

• 1 a schematic view of an actuation device in a micromechanical component according to an embodiment of the present invention;
• 2nd a schematic view of an actuation device according to an embodiment of the present invention;
• 3rd a schematic side view of a micromechanical component according to an embodiment of the present invention; and
• 4th a schematic plan view of a micromechanical component according to an embodiment of the present invention; and
• 5 is a schematic block diagram of a method for producing a micromechanical component according to an embodiment of the present invention.

In the figures, the same reference symbols designate the same or functionally identical elements.

1 shows a schematic view of an actuation device in a micromechanical component according to an embodiment of the present invention.

In the 1 becomes a part of the actuation device 1 shown which, for example, a sub-segment of a circular actuation device 1 , approximately according to the 2nd , may include.

The actuation device 1 for a micromechanical component comprises a suspension frame 3rd ; a plurality of bending beams 4th with a spring material FM , the bending beam 4th each with the hanging frame 3rd are mechanically connected and extend laterally from it; a plurality of actuators 4a , the actuators 4a with the bending beams 4th are mechanically connected; a ring element 5 which with the bending beam 4th is mechanically connected and from the hanging frame 3rd is laterally spaced and has less flexibility than the bending beams 4th ; a plurality of spring elements 6 which with the ring element 5 are mechanically connected and separate from the ring element 5 on one of the hanging frames 3rd laterally extend away from the opposite side; and a central segment to be moved 7 , the spring elements 6 the central segment 7 with the ring element 5 connect mechanically.

The present embodiment enables an actuation device 1 can be achieved with a small size. The spring elements 6 can have a rectangular frame with two narrow connectors each VS include, with a connector to the central segment 7 and the other connector to the frame member 5 can extend.

2nd shows a schematic view of an actuation device according to an embodiment of the present invention.

The internal mechanical tension of the bending beam can advantageously extend radially inwards to the associated spring element 6 continue, but over the frame element 5 on all spring elements 6 be balanced. In other words, through the cantilever 4th a mechanical bending moment is generated radially inwards. Since the bending beam over the rigid frame element 5 are connected to one another, and the bending effect of all the bending beams can be transferred to the stroke of the frame element, the same deflection amplitude of the edge of the central segment can be achieved on the spring elements 7 be achieved and the central segment 7 are moved (actuated) with a high degree of parallelism with respect to the rest position. The bending beams are advantageous on an annular suspension frame 3rd attached, which with a first substrate 9 can be connected or even a first substrate 9 may include.

The bend can go over the ring element 5 continue radially inward and the spring elements 6 deflect and the central segment 7 deflect or tilt essentially parallel to the base plane, up or down, depending on the arrangement of the actuator elements on the bending beam. For deflection, the actuators can be arranged on the bending beams on the side of the suspension frame and / or on the side of the ring element (not shown).

The central segment 7 can one with the spring elements 6 connected stenter 7a and an inner membrane 7b include. Due to the design with a tenter frame, for example in the case of optically transmissive MEMS components, a mirror layer can stand free as a membrane, so that absorption in the spring material and reinforcement layer as in the rigid central segment 7 doesn't matter. Furthermore, it can be optically advantageous if such a mirror layer adjoins air, vacuum or a gas instead of a solid on both sides.

After 2nd can use the bending beams 4th an arrangement of strips lying side by side and describing a circular shape, which form the hanging frame 3rd with the ring element 5 connect, and the ring element 5 can already be raised or lowered from a basic level. The hanging frame 3rd can serve as anchoring of the bending beams. The ring element 5 can thus serve as a fixation for the ends of the bending beams on the ring element side, as a result of which, for example, manufacturing tolerances with regard to piezoelectric layers of the actuator can be partially compensated for. The ring element 5 can also represent a fixation for other actuators. Furthermore, the ring element 5 in connection with the bending beam 4th and the spring elements 6 serve as a design element to influence the bending line of the hanging frame in addition to design properties 3rd to the central segment 7 to serve. Because the ring element 5 can have a high torsional stiffness, the bending moment on the central segment can advantageously 7 be reduced, thereby reducing the warpage of the central segment 7 can be achieved. The ring element 5 can also mechanical decoupling of the central segment 7 , cause the ring element itself and the area with the attached actuators. As a result, an excessive decrease in the natural frequency of the actuator device and its elements can advantageously be reduced or prevented, which would result in vibration and gravitational sensitivity of the actuator device.

The spring elements 6 can to the ring element 5 towards and also towards the central segment 7 one narrow connection point each VS comprise and in between have a frame shape, for example with a rectangular or square shape. The bending moment that continues inwards can occur in the interior due to the torsion and / or bending of the spring elements 6 between ring element 5 and central segment 7 are cushioned, the narrow or small-area connection point (s) also warping the central segment 7 can reduce or avoid. Because the spring elements 6 and the bending beams 4th are deformed during actuation, they show advantageously a lower bending stiffness in the actuation direction than the ring element, the suspension frame and the central segment, the spring elements 6 and the bending beams 4th can advantageously comprise the same material and in particular the same spring material. A bending stiffness of the spring elements and bending beams should, however, be sufficiently high so that the natural frequency of the mechanical system (elements of the actuator device) does not become too low and this can become sensitive to vibration and inclination. Typical natural frequencies for a robust overall system are in the range of several kHz. The bending stiffness results from the mechanical material properties and the chosen thickness. An advantageous thickness for polySi (PolySilicon) could therefore be approx. 10-50µm. Thus, the ring element and the central segment 7 only bend slightly or not at all during actuation.

The majority of the bending beams 4th can, for example, at regular intervals around the central segment 7 be arranged around. On the other hand, it is also possible that the bending beam is only concentrated in two opposite areas around the central segment 7 can be arranged (not shown).

3rd shows a schematic side view of a micromechanical component according to an embodiment of the present invention.

The first mirror device SP1 can be used as a micromirror, advantageously as at least one or more mirror layers on the central segment 7 be arranged and be carried out in MEMS design. The second mirror device SP2 can also comprise one or more mirror layers, the micromechanical component 2nd in this case a tunable optical filter such as a Fabry-Perot interferometer.

Furthermore, it is possible for the micromechanical component 2nd a base substrate S on which the first substrate with the actuation device 1 is arranged. The substrates can advantageously be bonded to one another using a bonding method. For example, the second substrate 10th on the first substrate 9 be arranged. If the first and second substrates over a bond frame B with a base substrate S can be connected between the base substrate S , the first substrate 9 and the second substrate 10th an advantageously hermetically sealed cavern is formed by the substrates. The encapsulation advantageously allows the mirror devices to be protected against environmental influences. An internal pressure can advantageously be enclosed in the encapsulation and damping of the system can be set. The base substrate S can include a cavity.

The actuation device 1 can advantageously be encapsulated in the cavern. The detector device D can be on or in the central segment 7 or on the second substrate 10th or on the base substrate S or be integrated into this, advantageously in a light path in the area above or below the central segment 7 . The detector device D can advantageously be light-sensitive and provide measurement data for a transmitted light intensity for purposes such as spectroscopy.

The ring element 5 and the central segment 7 could also consist of a layer of spring material and a reinforcement layer 8th exist, whereby a bending stiffness of these design elements can be increased. A total thickness of the central segment 7 and / or the ring element 5 can for example 50 to have. The actuators 4a can be electrostatic or piezoelectric. In the case of the piezoelectric actuators, these can advantageously be arranged above the spring material. In the case of an electrostatic actuator, this can have comb structures in the spring material and / or the reinforcement layer 8th be pronounced (not shown). The bending beams 4th can both on the side of the hanging frame 3rd as well as on the side of the ring element 5 Actuators 4a have what can enable actuation in two directions. In this way, a larger travel range for the movement of the central segment 7 be achieved. Such bidirectional actuation can compensate for undesired, production-related pre-deflections of the central segment. The actuators and the spring elements allow a vertical deflection (translation) of the central segment 7 done with all actuators 4a can be controlled and the bending beams 4th can deflect immediately. It is also possible that the central segment 7 can be tilted or rotated, the actuators 4a in this case can be controlled / activated differently and a different deflection of the bending beam can result.

As an alternative to executing the 3rd can also use two first substrates 9 can be bonded / fastened one above the other with bending beams and actuators in such a way that the mirror devices are arranged opposite one another. In addition, a base substrate and further substrates such as the second substrate can be present.

In the 3rd is also an insulator layer INS shown, which can serve as an etch stop for the manufacturing process when a spring trench FG and an actuator trench AG in the first substrate 9 be trained if that Central segment 7 and the ring element 5 as well as the hanging frame 3rd from the first substrate 9 getting produced.

4th shows a schematic top view of a micromechanical component according to an embodiment of the present invention.

The top view of the 4th advantageously corresponds to the component from the 3rd . The spring elements 6 can also be designed as a torsion spring and a bending moment of a bending beam via connection points VS to the central segment 7 Reduce. The bending beams can advantageously the actuator trench AG span and the spring elements 6 can a trench FG spanning.

In an edge area outside the actuation device 1 can electrical leads ZL for the actuators in the first substrate 9 or second substrate 10th be integrated. The leads can also be routed in the reinforcement layer or the spring layer (not shown). If the leads in the reinforcement layer 8th and / or in the spring material, the risk of a short circuit with any metallic bonding of the bonding frame can advantageously be reduced.

5 shows a schematic block diagram of a method for producing a micromechanical component according to an embodiment of the present invention.

The method for producing a micromechanical component is provided S1 a first substrate; an application S2 an insulator layer on the first substrate and patterning S2a the insulator layer in areas for a spring trench which laterally runs around a central segment and an actuator trench which runs around the spring trench at a certain distance and a ring element or frame element runs between the spring trench and the actuator trench; an application S3 a spring material on the first substrate and on the insulator layer and a mirror material for a first mirror device on the central segment; a contribution S4 a spring trench and an actuator trench in the first substrate up to the insulator layer; and a removal S5 the insulator layer INS in the spring trench and in the actuator trench.

The determined distance can advantageously describe a width of the ring element.

Although the present invention has been fully described above on the basis of the preferred exemplary embodiment, it is not restricted to this but can be modified in a variety of ways.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 9250418 B2 [0003]

Claims (12)

Actuating device (1) for a micromechanical component (2) comprising - A hanging frame (3); - A plurality of bending beams (4) with a spring material (FM), wherein the bending beams (4) are each mechanically connected to the suspension frame (3) and extend laterally therefrom; - a plurality of actuator devices (4a), the actuator devices (4a) being mechanically connected to the bending beams (4); - A ring element (5) or frame element which is mechanically connected to the bending beam (4) and laterally spaced from the suspension frame (3) and has less flexibility than the bending beam (4); - A plurality of spring elements (6) which are mechanically connected to the ring element (5) and laterally extend away from the ring element (5) on a side facing away from the suspension frame (3); and - A central segment (7) to be moved, the spring elements (6) mechanically connecting the central segment (7) to the ring element (5). Actuating device (1) after Claim 1 , in which the central segment (7) comprises a planar extent and can be moved or rotated perpendicular to the planar extent by means of the actuator devices (4a) via the bending beams (4) and the spring elements (6). Actuating device (1) after Claim 1 or 2nd , in which the bending beam (4) and the spring elements (6) comprise the same spring material (FM). Actuating device (1) according to one of the Claims 1 to 3rd , in which the ring element (5) and the central segment (7) comprise the same material and a reinforcing layer (8). Actuating device (1) after Claim 4 , in which the ring element (5) and the central segment (7) comprise the same spring material (FM) as the bending beams (4) and the spring elements (6). Actuating device (1) according to one of the Claims 1 to 5 , in which the actuating element (7) comprises a clamping frame (7a) connected to the spring elements (6) and an inner membrane (7b). Micromechanical component (2) comprising - an actuation device (1) according to one of the Claims 1 to 6 ; and - a first substrate (9), the suspension frame (3) being fastened to the first substrate (9) or the first substrate (9) itself representing the suspension frame (3) and the bending beam (3) running laterally. Micromechanical component (2) according to Claim 7 , in which the central segment (7) comprises a first mirror device (SP1). Micromechanical component (2) according to Claim 8 which comprises a second substrate (10) with a second mirror device (SP2), the second substrate (10) being arranged on the first substrate (10) and the first mirror device (SP1) being arranged opposite the second mirror device (SP2). Micromechanical component (2) according to Claim 9 , which is designed as a spectrometer device and comprises a light-sensitive detector device (11) which is arranged downstream of the first mirror device (SP1) and the second mirror device (SP2) in a light emission direction (Lab). Method for producing a micromechanical component (2) comprising the steps: - Providing (S1) a first substrate (9); - Application (S2) of an insulator layer (INS) on the first substrate (9) and structuring (S2a) of the insulator layer (INS) in areas for a spring trench (FG), which laterally runs around a central segment (7) and an actuator trench (AG) , which runs around the spring trench (FG) at a certain distance and runs around a ring element (5) or frame element between the spring trench (FG) and actuator trench (AG); - Applying (S3) a spring material (FM) on the first substrate (9) and on the insulator layer (INS) and a mirror material for a first mirror device (SP1) on the central segment (7); - Introducing (S4) a spring trench (FG) and an actuator trench (AG) into the first substrate (9) up to the insulator layer (INS); and - Remove (S5) the insulator layer (INS) in the spring trench (FG) and in the actuator trench (AG). Procedure according to Claim 11 , in which an application of a piezo actuator layer on the spring material (FM) over the actuator trench (AG) and provision of a second substrate (10) with a second mirror device (SP2) and arrangement of the second substrate (10) over the first substrate (9) takes place so that the second mirror device (SP2) is opposite the first mirror device (SP1), and a base substrate (S) is provided which comprises a cavity over which the first substrate (9) is arranged.

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