DE102008003242A1 - Micromechanical component i.e. inertial sensor, has micromechanical functional layer extending over specific percentage of substrate thickness perpendicular to main extension plane of substrate - Google Patents

Abstract

The component (1) has a micromechanical functional layer that is formed in the material of a substrate (24), where the substrate has a main extension plane (11). The substrate and the micromechanical functional layer are provided in a plane that is arranged parallel to the main extension plane. The micromechanical functional layer extends over 30 percentage of the substrate thickness perpendicular to the main extension plane. The functional layer covers another layer in a direction perpendicular to the main extension plane. An independent claim is also included for a method for manufacturing a micromechanical component.

Description

State of the art

The The invention is based on a micromechanical component after Preamble of claim 1.

Such base elements are well known. For example, from the document DE 43 15 012 B4 a sensor with a movable monocrystalline sensor element is known, wherein the movable sensor element is mounted on a plate-shaped substrate made of monocrystalline silicon and wherein the attachment of the sensor element is provided on the substrate by means of an insulating layer disposed between the sensor element and the substrate.

Disclosure of the invention

The Micromechanical component according to the invention and the inventive method for the preparation a micromechanical device according to the have sibling claims against the The prior art has the advantage that with a comparatively low Number of manufacturing steps a micromechanical device can be produced, which has a comparatively thick functional layer perpendicular to the main plane of extension. Thus, for example, a Increasing the aspect ratio of capacitive Sensors achieved, thereby reducing the required chip area of the capacitive sensors compared to the prior art becomes. The manufacturing cost of the micromechanical device are therefore considerably reduced. The functional layer is off formed the material of the substrate, which is preferably a monocrystalline Silicon includes, and overlaps in a normal to the surface the main extension plane vertical direction with the substrate.

One Another object of the present invention is a micromechanical Component having a main extension plane exhibiting substrate and a parallel to the main extension plane formed further Layer, wherein the substrate is structured such that the substrate has a micromechanical functional layer, which in a plane parallel to the main extension plane in the substrate is arranged and which in a direction perpendicular to the main extension plane Direction at least partially overlaps the other layer. Advantageously, therefore, the micromechanical functional layer formed by a corresponding structuring of the substrate, so that the structures of the micromechanical functional layer in particular be formed by the material of the substrate. The micromechanical Functional view is particularly advantageous by the further layer, which preferably has an epitaxial layer applied to the substrate covers, covered, so that movable elements of the micromechanical Functional layer electrically contacted by the further layer, mechanically fixed and / or against mechanical and / or chemical influences to be protected. In particular, it is advantageous in this way according to the invention possible that the functional layer of the micromechanical device on the side of the further layer, through the overlapping or continuous further layer is completed, in particular hermetically sealed and thus the function of a capping is taken over by the further layer.

advantageous Refinements and developments of the invention are the subclaims, and the description with reference to the drawings.

According to one preferred development is provided that the micromechanical Functional layer perpendicular to the main plane of extension at least over 50%, preferably at least over 75%, and more preferably extends at least over 90% of the substrate thickness. Especially is advantageous by such an increase in the functional layer thickness the aspect ratio of the micromechanical device further increased, which reduces the chip area and thus reduce the cost of production.

According to one Another preferred embodiment provides that the micromechanical functional layer has movable elements and / or that the substrate another Layer has. Advantageously, by the movable Elements in particular electrodes can be realized, which are preferred for the capacitive measurement of acting on the movable elements Inertia forces are provided. Especially preferred allow the further layer and / or parts of the further layer the electrical contacting of the movable elements and / or the formation of tracks. Very particularly preferably the substrate and / or the functional layer counterelectrodes with respect the electrodes formed by the movable elements.

In accordance with a further preferred development, it is provided that the micromechanical component has a capping layer, the capping layer preferably being arranged on a first side of the substrate and the further layer being arranged on a second side of the substrate. The capping layer is particularly advantageous for protecting the micromechanical function Layer, wherein preferably the vibrational capabilities of the movable elements are adjusted by the inclusion of a special atmosphere in the micromechanical functional layer. The micromechanical functional layer is particularly advantageously protected and / or atmospherically sealed by the further layer on a side opposite the capping layer perpendicular to the main extension plane.

According to one Another preferred embodiment provides that the substrate a cavern, the cavern preferably in the range of movable elements and / or formed on the first side. The formation of the cavern allows in advantageous Way a comparatively precise definition of the functional layer thickness perpendicular to the main extension plane.

According to one Another preferred development is provided that between the substrate and the further layer at least partially an insulating layer is arranged and / or that the further layer trenches perpendicular to the main plane of extension and / or that the having further layer contact pads. Allow in an advantageous manner Contact pads the electrical contacting of the micromechanical Component, while through the trenches an electric Isolation is realized by parts of the further layer. The insulation layer acts preferably for electrical insulation of the functional layer and / or the substrate of the further layer and / or for attachment the further layer on the functional layer and / or the substrate. Particularly preferred is the insulating layer in the trenches arranged while the insulating layer in the functional layer at least partially etched away.

According to one Another preferred embodiment provides that the micromechanical component is an inertial sensor. in an advantageous manner by the micromechanical Component an inertial sensor with a comparatively high aspect ratio realized.

One Another object of the present invention is a method for producing a micromechanical according to the invention Component, wherein in a first process step, a substrate is provided and wherein in a second process step on the substrate, a further layer is applied and wherein Furthermore, in a third method step, the substrate is structured. Particularly advantageous is the structuring of the substrate even the functional layer of the material of the substrate in the Substrate formed. Because of the comparatively large Substrate thicknesses perpendicular to the main plane of extension thus become enables functional layers compared to the state of the art which a much larger aspect ratio exhibit. The further layer is preferably used for electrical Contacting of the substrate and / or the functional layer.

According to one preferred training is provided that before the time second process step, the substrate in a fourth process step is coated on at least one side with an insulating layer and / or before the third process step, the further layer in a fifth process step coated with a further insulating layer becomes. Part of the substrate, the Functional layer and / or the other layer from each other electrically isolated.

According to one Another preferred development is provided that before the third step, the further layer in a sixth Process step structured and / or the substrate in a seventh Process step is etched. Particularly advantageous the structuring of the further layer the electrical insulation of parts of the further layer for electrical contacting of the functional layer and / or the substrate and / or for the formation of conductor tracks.

The etching of the substrate allows a comparatively precise Determining the substrate or functional layer thickness.

According to one Another preferred embodiment provides that after the fourth process step, the insulation layer in an eighth step is structured and / or that after the fifth process step structured the further insulation layer in a ninth step and / or that in a twelfth process step the insulation layer is etched. Especially advantageous allows the structuring of the insulation layer and / or the further insulation layer both the definition of mechanical solid connections between the insulating layers and the substrate and / or the further layer, as well as the definition of wegätzbaren Insulation layers, which, for example, in the functional layer by an etching process, the formation of the movable elements enable.

According to a further preferred development, it is provided that, after the third method step, the substrate is at least partially covered by a capping layer in a tenth method step and / or at least one contact pad is arranged on the further layer in an eleventh method step. Particularly advantageously, the arrangement of at least one contact pad allows the electrical contacting of the micromechanical device, while the capping layer for protection and / or the atmosphere rule sealing the micromechanical functional layer acts.

embodiments The present invention are illustrated in the drawings and explained in more detail in the following description.

Brief description of the drawings

It demonstrate

1a 1 is a schematic side view of a first precursor structure for producing a micromechanical device according to a first embodiment,

1b 1 is a schematic side view of a second precursor structure for producing a micromechanical device according to the first embodiment,

1c FIG. 2 shows a schematic side view of a third precursor structure for producing a micromechanical device according to the first embodiment, FIG.

1d FIG. 2 shows a schematic side view of a fourth precursor structure for producing a micromechanical component according to the first embodiment, FIG.

1e FIG. 2 shows a schematic side view of a fifth precursor structure for producing a micromechanical device according to the first embodiment, FIG.

1f FIG. 2 shows a schematic side view of a sixth precursor structure for producing a micromechanical component according to the first embodiment, FIG.

1g a schematic side view of a micromechanical device according to the first embodiment and

2 a schematic perspective view of a micromechanical device according to a second embodiment.

Embodiment (s) of the invention

In In the different figures, the same parts are always the same Reference numerals provided and are therefore usually also each named only once.

In 1a is a schematic side view of a first precursor structure for producing a micromechanical device to illustrate a first, fourth and eighth process step 1 according to a first embodiment, wherein in the first method step, the substrate 2 provided. The substrate 2 is in the fourth step on both sides, each with an insulating layer 8th coated, wherein one of the insulating layers 8th is structured in the eighth process step. The substrate 2 preferably comprises a monocrystalline silicon wafer. At the insulation layer 8th it is preferably a thermal oxide, which is structured in a standard method, such as Tegal, LAM. The substrate 2 has a main extension plane 11 on.

In 1b is a schematic side view of a second precursor structure for producing a micromechanical device to illustrate a second and sixth method step 1 according to the first embodiment, wherein in the second method step on the substrate 2 or the structured insulation layer 8th another layer 3 is applied, which preferably comprises a polycrystalline silicon, which is particularly preferably deposited by an epitaxial process. In a sixth method step, the further layer 3 structured, in particular trenches 9 in the further layer 3 be formed by trench method. The further layer is preferred 3 planarized by a standard method.

In 1c is a schematic side view of a third precursor structure for producing a micromechanical device to illustrate a fifth and ninth method step 1 according to the first embodiment, wherein in the fifth method step, the further layer 3 with another insulation layer 8th' is covered, which is structured in a subsequent ninth step. The trenches are preferred 9 through further insulation layer 8th' completely filled, with the further insulation layer 8th' particularly preferably comprises a thermal oxide, which very particularly preferably by means of a MORI method for producing conductive structures in the further insulating layer 8th' is structured.

In 1d is an illustration of an eleventh process step, a schematic side view of a fourth precursor structure for producing a micromechanical device 1 illustrated in the first embodiment, wherein in the eleventh step on the further insulating layer 8th' contact pads 12 are arranged, which for electrical contacting of the micromechanical device 1 serve. The contact pad 12 preferably comprises a metal surface and / or a metallic conductor track.

In 1e is an illustration Seventh method step, a schematic side view of a fifth precursor structure for producing a micromechanical device 1 according to the first embodiment, wherein in the seventh process step, the substrate 2 is etched. Before the seventh process step, the fifth precursor structure is preferably rotated 180 degrees, with the axis of rotation in the main plane of extension 11 lies. Particularly preferred is a cavern 7 in the substrate 2 etched, so that a desired residual thickness of the substrate perpendicular to the main plane of extension between the substrate surface and the insulating layer 8th is set. The etching process is especially on a first page 5 of the substrate 2 performed, which is perpendicular to the main plane of extension 11 on the opposite side of a second page 6 with the further layer 3 with respect to the substrate 2 is arranged.

In 1f FIG. 3 is a schematic side view of a sixth precursor structure for producing a micromechanical device, to illustrate a third and a twelfth process step. FIG 1 according to the first embodiment, wherein in the sixth method step, the substrate 2 is structured and in a subsequent twelfth process step, the insulation layer 8th is etched, preferably by means of a gas phase etching process. Particularly preferred is the substrate 2 in the area of the cavern 7 trimmed, so that after the twelfth process step in the substrate 2 movable elements 2 ' from the material of the substrate 2 be formed

In 1g is a schematic side view of the micromechanical device 1 illustrated in the first embodiment, wherein in a tenth method step, the micromechanical device 1 with a capping layer 4 is covered. Preferably, the capping layer comprises 4 a thin-film cap, which is on the first page 5 of the substrate 2 is arranged. The cap wafer 4 is particularly preferably by means of a seal-glass connection or by means of an anodic bonding process to the substrate 2 attached.

In 2 is a schematic perspective view of a micromechanical device 1 according to a second embodiment, wherein exemplified a comb structure 20 from moving electrodes 21 and fixed counterelectrodes 22 is shown, wherein the movable electrodes 21 fixed to each other and spring structures 23 with the substrate 24 are elastically connected.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4315012 B4 [0002]

Claims (13)

Micromechanical device ( 1 ) with a substrate ( 2 ) and at least partially in the material of the substrate ( 2 ) formed micromechanical functional layer ( 2 ' ), the substrate ( 2 ) a main extension plane ( 11 ) and wherein the substrate ( 2 ) and the micromechanical functional layer ( 2 ' ) at least partially in a plane parallel to the main plane ( 11 ) level ( 11 ' ) are provided lying, characterized in that the micromechanical functional layer ( 2 ' ) perpendicular to the main plane of extension ( 11 ) at least over 30% of the substrate thickness ( 10 ) is provided extending. Micromechanical device ( 1 ), in particular according to claim 1, having a main extension plane ( 11 ) having substrate ( 2 ) and one parallel to the main extension plane ( 11 ) formed further layer ( 3 ), characterized in that the substrate ( 2 ) is structured such that the substrate ( 2 ) a micromechanical functional layer ( 2 ' ), which in one to the main extension plane ( 11 ) parallel plane ( 11 ' ) in the substrate ( 2 ) is arranged and which in a to the main extension plane ( 11 ) vertical direction ( 10 ' ) at least partially the further layer ( 3 ) overlaps. Micromechanical device ( 1 ) according to one of the preceding claims, characterized in that the micromechanical functional layer ( 2 ) perpendicular to the main plane of extension ( 11 ) at least over 50%, preferably at least over 75%, and more preferably at least over 90% of the substrate thickness ( 10 ). Micromechanical device ( 1 ) according to one of the preceding claims, characterized in that the micromechanical functional layer ( 2 ' ) has movable elements and / or that the substrate ( 2 ) another layer ( 3 ), wherein the further layer ( 3 ) preferably comprises an epitaxial layer. Micromechanical device ( 1 ) according to one of the preceding claims, characterized in that the micromechanical component ( 1 ) a capping layer ( 4 ), wherein preferably the capping layer ( 4 ) on a first page ( 5 ) of the substrate ( 2 ) and the further layer ( 3 ) on a second page ( 6 ) of the substrate ( 2 ) is arranged. Micromechanical device ( 1 ) according to one of the preceding claims, characterized in that the substrate ( 2 ) a cavern ( 7 ), wherein the cavern ( 7 ) preferably in the region of the movable elements ( 2 ' ) and / or on the first page ( 5 ) is trained. Micromechanical device ( 1 ) according to one of the preceding claims, characterized in that between the substrate ( 2 ) and the further layer ( 3 ) at least partially an insulating layer ( 8th ) and / or that the further layer ( 3 ) Trenches ( 9 ) perpendicular to the main plane of extension ( 11 ) and / or that the further layer ( 3 ) Contact Pads ( 12 ) having. Micromechanical device ( 1 ) according to one of the preceding claims, characterized in that the micromechanical component ( 1 ) is an inertial sensor. Method for producing a micromechanical component ( 1 ) according to one of the preceding claims, characterized in that in a first process step, a substrate ( 2 ), wherein in a second process step on the substrate ( 2 ) another layer ( 3 ) and wherein in a third process step the substrate ( 2 ) is structured. Method according to claim 9, characterized in that before the second method step, the substrate ( 2 ) in a fourth method step at least on one side with an insulating layer ( 8th ) and / or before the third process step, the further layer ( 3 ) in a fifth method step with a further insulation layer ( 8th' ) is coated. Method according to one of claims 9 or 10, characterized in that before the third process step, the further layer ( 3 ) structured in a sixth method step and / or the substrate ( 2 ) is etched in a seventh process step. Method according to one of claims 9 to 11, characterized in that after the fourth process step, the insulating layer ( 8th ) is structured in an eighth method step and / or that after the fifth method step the further insulation layer ( 8th' ) is structured in a ninth method step and / or that in a twelfth method step the isolation layer ( 8th ) is etched. Method according to one of claims 9 to 12, characterized in that after the third process step, the substrate ( 2 ) in a tenth process step at least partially from a capping layer ( 4 ) and / or on the further layer ( 3 ) in an eleventh method step at least one contact pad ( 12 ) is arranged.