Method for producing microelectromechanical component structure, microelectromechanical component structure, microelectromechanical device and microelectromechanical speaker

Abstract

The invention relates to a method (100) for producing a microelectromechanical component structure (200), comprising a first substrate (20) having a substrate surface (21) and comprising at least one vertical functional region (F) which extends substantially perpendicular to the substrate surface (21), the at least one vertical functional region (F) is bounded by an adjoining sacrificial region (O) by producing and passivating at least one vertical trench (70) and is released by removing the sacrificial region (O), a bonding surface (23) being produced by applying at least one layer (22) to the substrate surface (21) of the first substrate (20), and wherein the at least one vertical functional region (F) is bonded to the bonding surface (23) by applying at least one layer (22) to the substrate surface (21) of the first substrate (20). A second substrate (30) is applied on the bonding surface (23), in which at least one vertical trench (70) is produced. The invention also relates to a microelectromechanical component structure (200), a microelectromechanical device (300) and a microelectromechanical loudspeaker (400).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electrical component structure, a microelectromechanical component structure, a microelectromechanical device, and a microelectromechanical loudspeaker. Background Technology

[0002] Microelectromechanical structures, also known as MEMS structures, and methods for manufacturing microelectromechanical structures, are known from the prior art.

[0003] DE 10 2015 206 996 A1 discloses a method for fabricating a layered microelectromechanical structure (MEMS) and a corresponding electronic structural element having a MEMS. The method includes providing a carrier substrate having a first surface, applying an insulating layer to the first surface, epitaxially growing a first silicon layer on the insulating layer, structuring the first silicon layer to form trenches in the first silicon layer, passivating the first silicon layer, wherein the trenches are filled and a passivation layer is formed on a side facing away from the first surface, structuring the passivation layer, wherein sacrificial regions and functional regions are formed in the first silicon layer, and the sacrificial regions are at least partially without a passivation layer on the side facing away from the carrier substrate, and finally removing the sacrificial regions.

[0004] EP 3 912 953 A1 describes a method for manufacturing MEMS structural elements, in which a first structural layer and a second structural layer are fabricated, and trenches and a mask layer are provided.

[0005] US 2015 / 0 274 ​​512 A1 provides a MEMS device and a method for manufacturing it, in which a first dielectric layer having an integrated circuit is formed on a first substrate, a second dielectric layer having an acceleration sensor is formed on the first dielectric layer, and a second substrate is applied on the second dielectric layer.

[0006] US 8 043 931 B1 relates to a method for fabricating a multilayer silicon structure by manufacturing a structured monolayer and orienting and bonding the monolayer. Summary of the Invention

[0007] According to the features of independent claim 1, a method for manufacturing a microelectromechanical component structure is proposed, the microelectromechanical component structure having a first substrate having a substrate surface and having at least one vertical functional region extending substantially perpendicular to the substrate surface, wherein the at least one vertical functional region is demarcated from an adjacent sacrificial region by generating and passivating at least one vertical trench and is released by removing the sacrificial region, wherein a bonding surface is created by applying at least one layer on the substrate surface of the first substrate, and wherein a second substrate is applied to the bonding surface, wherein at least one vertical trench is generated in the second substrate.

[0008] In other words, the proposed method proposes to generate microelectromechanical component (MEMS) structures with layered structures having more than one substrate, wherein, in principle, a higher layer thickness can be achieved by using multiple substrates than, for example, through epitaxial growth or deposition processes. Therefore, it is possible, through the proposed method, to fabricate MEMS structures and functional regions with large vertical extensions, for example, greater than 100 μm, using a simplified process. Furthermore, the proposed method can fabricate laterally elongated structures, for example, with widths less than 20 μm, which can also be achieved with narrow tolerance bandwidths, for example, less than 10 μm, less than 5 μm, or less than 2 μm. The elongated structure, for example, can improve the mobility of the functional regions and reduce their stiffness. Through a fabrication method with passivated vertical trenches and optional horizontal etch-stop regions (to be explained later), which can separately demarcate sacrificial and functional regions and enable the release of functional regions by removing sacrificial regions, or alternatively, the separation of functional regions at different potentials, a high degree of configurational freedom with virtually arbitrary vertical and horizontal structures can be achieved. Functional regions can form mechanical or electrical connections, and may extend over the entire vertical length of a component structure or its carrier, such as a MEMS chip, or only over a portion of the component structure with locally customized configurations. In this case, movable structures may also be created, or electrical connections and insulation may be freely defined and configured, such as through vertical and / or horizontal potential guidance or separation. Furthermore, horizontal potential guidance may be used for mechanical stability purposes or for horizontal connections in vertically staggered structures. Moreover, trenches can be fabricated simply and with high precision in a second substrate or in another substrate to be explained later, compared to trench fabrication in a sequence of material layers with comparable vertical extension scales and a single applied material layer. Furthermore, microelectromechanical structures can be fabricated economically efficiently using the proposed method because large layer heights can be achieved at low cost via a substrate compared to material layers with comparable vertical extension scales fabricated through epitaxial growth or deposition processes. Furthermore, the proposed method is applicable to CMOS and high-temperature environments. For example, attaching a second or additional substrate via direct wafer bonding is more advantageous in terms of heat and energy compared to epitaxial growth processes for comparable structure heights. For instance, epitaxial growth processes may require process temperatures exceeding 1000°C, while wafer bonding can occur at temperatures below 100°C. Furthermore, small wafer warpage can be expected in the proposed method. By creating a stable, robust layer structure on the substrate, there are no movable structures during the method, and the subsequent structure is fixed during process flow via vertical and horizontal passivation and etch-stop structures, ensuring high process safety.The deep structuring of component structures is achieved through the contouring of functional and sacrificial regions, which eliminates the need for large-volume etching in trench processes and allows for more precise definition of structural elements. This results in reduced trench angles and smaller tilts.

[0009] The first substrate, also commonly referred to as a wafer, can be, for example, a silicon substrate, particularly a single-crystal implementation. The first substrate can form a planar carrier structure for microelectromechanical components (MEMS) having a bottom surface and a substrate surface opposite the bottom surface. Further component structures can be constructed as a layer sequence on this substrate surface. The bottom surface and the substrate surface can have the largest area proportion of the first substrate and a length and width, respectively, greater than the depth of the first substrate. The extending direction of the substrate surface can define a horizontal plane of the MEMS structure. The component structure can, for example, have a rectangular cross-sectional profile.

[0010] The vertical functional regions generated by the proposed method can have a vertical extension scale perpendicular to the substrate surface, which is larger than the horizontal extension scale of functional regions parallel to the substrate surface. The vertical functional regions can be implemented, in particular, as elongated structures, for example, having a width of less than 20 μm, or having an extension scale in the vertical direction that is many times, for example, at least five or at least ten times larger than that along the horizontal width and / or depth directions. As elongated structures, the vertical functional regions can advantageously fulfill specific functions of microelectromechanical component structures, such as forming movable structures and thereby forming sensing elements, or undertaking mechanical functions, such as supporting elements spaced apart from each other.

[0011] Vertical trenches can be created, for example, using trenching processes to produce elongated trenches with high precision. At least one trench created in the second substrate can advantageously extend to the bonding surface of the first substrate. To create the trenches, the location of the trenches or trenches can be predefined by a structured etch stop layer acting as a mask layer. Passivation of the created vertical trenches can be performed as surface passivation of the trench surface and, for example, by filling with a passivation material that acts as an etch barrier, causing the etching process to terminate at the passivated trench. For example, a horizontal etch stop layer can be applied to the second substrate having the vertical trenches, which penetrates the vertical trenches due to capillary effects and passivates the vertical trenches.

[0012] Applying at least one layer can involve applying a material layer made of a material, particularly a semiconductor-based material. Such a material layer can be, for example, a monocrystalline, polycrystalline, or amorphous silicon layer, or a dielectric layer having a silicon compound, such as silicon dioxide (SiO2) or silicon nitride (Si3N4). Furthermore, applying at least one layer can involve applying auxiliary layers, such as etch stop layers or sacrificial layers, which may optionally be removed during or subsequently by means of an HF vapor phase etching process. Etch stop layers or sacrificial layers may, for example, have a silicon compound, such as silicon dioxide (SiO2) or silicon nitride (Si3N4). Etch stop layers can, for example, define horizontal boundaries within the component structure and protect adjacent structural regions from etching. In particular, it is conceivable to set etch stop regions in segments of the component structure where subsequent vertical constructions should terminate. Furthermore, applying at least one layer can involve applying a sequence of layers, which may, for example, have one or more material layers and / or one or more auxiliary layers. Additionally, the applied layers may optionally be structured, for example, by etching, to form layer regions spaced apart from each other.

[0013] The second substrate, and other substrates mentioned later, can be implemented similarly or identically to the first substrate in terms of material and size. For example, the second substrate or other substrate can advantageously be a silicon substrate, particularly implemented in a single crystal. According to one embodiment, the first substrate and the second substrate or other substrate can have substantially the same substrate height. Alternatively, it is conceivable that the second substrate or other substrate has a larger or smaller substrate height to be able to define a personalized layer height for the microelectromechanical component structure. The substrate height can also be affected, for example, by thinning the second substrate or other substrate. The application of the second substrate or other substrate can be performed, for example, by means of a wafer-to-wafer bonding process.

[0014] The bonding surface can be the surface of a layered structure facing away from the first substrate, the layered structure having a first substrate and at least one layer, wherein the bonding surface can extend parallel to the substrate surface of the first substrate. The bonding surface is configured to attach a second substrate to the layered structure up to the present time and forms a boundary surface between the at least one layer applied to the first substrate and the second substrate. In this case, it is advantageous to create a continuous bonding surface such that the second substrate can be planarly supported on the bonding surface. In particular, a structured layer having layer segments spaced apart from each other due to structuring can be filled with material in such a way that a continuous bonding surface is created.

[0015] After introducing and passivating at least one vertical trench, or at the end of the method, the functional region can be released by removing adjacent sacrificial regions. Multiple, such as two or more, sacrificial regions may also be adjacent to the functional region, and these sacrificial regions are removed to release the functional region. Removal can be performed by an etching process, which may terminate vertically on the passivated trench and horizontally on an auxiliary layer, such as an etch stop layer. The etching process may be used, for example, to remove silicon material. The etching process may be, for example, an isotropic plasma etching process using, for example, sulfur hexafluoride (SF6), or a vapor-phase etching process using, for example, xenon difluoride (XeF2). Removal of the sacrificial regions may begin from the surface of the last applied substrate and / or from the back side of the first substrate opposite the substrate surface. Alternatively, after removing the sacrificial regions, the passivation and etch stop materials may be removed from the component structure to induce complete release of the functional region.

[0016] According to one embodiment, the bonding surface of the first substrate can be generated by applying and structuring a first etch stop layer to form etch stop regions spaced apart from each other and by filling the gaps between the etch stop regions with a material layer. This allows for the targeted generation of bonding surfaces that can provide the etch stop regions as etch barriers, for example, to limit the depth of vertical trench introduction. Furthermore, the etch stop regions can form, for example, horizontal boundaries between sacrificial regions and functional regions of a component structure, such that the etch process for removing the sacrificial regions terminates at the etch stop regions and protects adjacent regions from etch erosion. The etch stop layer can be, for example, a silicon dioxide layer or a silicon nitride layer. The etch stop layer can be applied, for example, by thermal oxidation and / or chemical vapor deposition. A high degree of configurational freedom is provided in the geometry of the functional and sacrificial regions through the horizontally oriented etch stop regions and the vertically oriented passivation trenches. Furthermore, overlapping or interlocking structural elements or structural regions can be realized. The material layer can be, for example, a semiconductor material, particularly silicon.

[0017] According to one embodiment, a single-crystal silicon material is used as a material layer to fill the gaps. Thus, for example, in the case of a first single-crystal substrate and a second single-crystal substrate, a continuous single-crystal vertical structure can be generated on the layer structure by the material layer. The continuous single-crystal vertical structure can have particularly advantageous mechanical and electrical properties. For example, the structure can have improved fracture strength or improved thermal conductivity. The material layer can be applied, for example, by epitaxial growth or by deposition, such as by chemical vapor deposition (CVD). According to other embodiments, it is also conceivable to use, for example, polycrystalline or amorphous silicon materials for the material layer.

[0018] According to one embodiment, the bonding surface of the first substrate can be chemically and / or mechanically processed to prepare for the application of the second substrate. This ensures reliable and planar attachment of the second substrate to the bonding surface. For example, planarization of the bonding surface can be performed. This processing can be performed, for example, by polishing, such as by a chemical mechanical polishing (CMP) process. Furthermore, it is conceivable, for example, to thin the second substrate to a predetermined structural height of the substrate surface of the second substrate after application to the bonding surface by means of grinding and / or polishing. The second substrate can have a thickness of more than 100 μm, more than 200 μm, or more than 400 μm before or after an optional thinning process.

[0019] According to one embodiment, another bonding surface can be formed on the substrate surface of the second substrate facing away from the first substrate, and the other substrate is applied to the bonding surface of the second substrate, creating at least one additional vertical trench in the other substrate. This allows for efficient and simple further increase in the vertical extension scale of the component structure and its functional regions. At least one additional vertical trench can be introduced, in particular, up to the bonding surface of the second substrate. The formation of the additional bonding surface can be similar to that of the bonding surface on the first substrate, for example, by applying and structuring an etch stop layer to form etch stop regions spaced apart from each other, and by filling the gaps between the etch stop regions with a material layer, wherein the material layer can be, for example, silicon, especially single-crystal silicon, and is applied, for example, by epitaxial growth or by deposition. The application of the other substrate can be similar to that of the second substrate, for example, by means of a wafer-direct bonding process. Furthermore, it is conceivable, for example, to thin the other substrate to a predetermined structural height on the substrate surface of the other substrate after application to the bonding surface by means of grinding and / or polishing. The other substrate can be before or after an optional thinning process, for example, having a thickness of more than 100 μm, more than 200 μm, or more than 400 μm. The additional vertical trenches can be created in a manner similar to where the trenches were created in the second substrate, for example, using a trenching process.

[0020] According to one configuration of the above embodiment, at least one layer is cyclically applied to the substrate surface of a substrate, a bonding surface is created, another substrate is applied, and at least one vertical trench is created and passivated in the other substrate until a predetermined target height of the vertical functional region is reached. This allows for efficient and simple further enhancement of the vertical extension dimensions of the component structure and its functional regions. After reaching the predetermined target height, which can be precisely adjusted optionally by thinning the last applied substrate, the functional regions can be released by removing the sacrificial regions.

[0021] According to one embodiment, the method may have a start process, a loop process, and a termination process, wherein the start process includes the following steps: -Provide the first base; - Apply the first etch stop layer to the first substrate; and -Etching stop regions with spacing between each other are created by structuring the first etch stop layer.

[0022] Therefore, the method can be divided into different method segments, where the initial method stage is called the start process and the final method stage is called the end process. The cyclic process can contain a series of method steps that can be repeated cyclically between the start and end processes at any frequency. Thus, a very diverse yet simple method can be provided, which is variable, for example, in terms of the number of cycles, and can be individually adapted to pre-given requirements for the component structure to be produced. Individual layer planes can be personalized and independently structured and configured, such that a segment of the overall layout of the component structure in each cycle can be fabricated with a personalized geometry. The initial start process enables entry into the cyclic process. During the start process, a first substrate is provided as a carrier structure, and a first etch stop layer is applied and structured on this first substrate. Further method steps can then be performed directly within the framework of the cyclic process.

[0023] According to one implementation, the cyclic process may include the following steps: - Fill the gaps between etch stop regions that are spaced apart by a layer of material to form a bonding surface; - Bond a second substrate or another substrate to the formed bonding surface; - Apply a second etch stop layer onto another substrate; -Etching stop regions spaced apart from each other are created by structuring a second etch stop layer; - At least one vertical trench is formed between the etch stop regions of the second etch stop layer, and especially up to the etch stop region of the first etch stop layer; - Apply a third etch stop layer and passivate at least one trench; and -Etching stop regions with spacing between each other are generated by structuring a third etch stop layer.

[0024] The above steps can be described as repeating sequentially and cyclically, for example, until the component structure or functional area of ​​the component structure reaches a predetermined vertical target height. Optionally, after filling the gaps between etch stop regions spaced apart by a material layer to form a bonding surface, planarization of the bonding surface can be performed to provide an optimized planar surface for attachment to a second substrate or another substrate. The etch stop regions of the second etch stop layer can form a mask, wherein the area between the etch stop regions can define the location of the trench to be generated. Optionally, the etch stop regions of the second etch stop layer can be removed after at least one vertical trench is generated, for example by etching and / or machining, to enable the uniform application of a third etch stop layer. The third etch stop layer can be generated, for example, by deposition or growth on the substrate surface of the second substrate facing away from the first substrate, wherein by applying the third etch stop layer, a passivation layer is also formed on the surface of at least one vertical trench, and the trench structure openings of the trench are closed on the substrate surface. The second and third etch stop layers can be, for example, silicon dioxide layers or silicon nitride layers. By providing the step of creating spaced-apart etch stop regions through a structured third etch stop layer, these spaced-apart etch stop regions can be filled with a material layer according to the first step of the cycle process upon restarting the cycle, forming another bonding surface and enabling bonding of another substrate to the bonding surface. Therefore, the cycle process of this method can be performed and repeated in a closed loop. In this case, it should be considered that in the second cycle run, the resulting vertical trenches are no longer introduced, particularly up to the etch stop regions of the first etch stop layer, but terminate, particularly at the etch stop regions of the third etch stop layer, which is the etch stop layer last applied in the previous cycle run. If no other restarting cycle is set, the spaced-apart etch stop regions of the third etch stop layer can form horizontal boundaries of the functional regions, protecting these boundaries from etch erosion upon subsequent release of the functional regions.

[0025] According to one implementation, the termination process may include the following steps: -Release functional areas by removing the sacrificed areas.

[0026] This can provide a microelectromechanical component structure with a released functional region. Optionally, the termination process may include a further step after the release, in which the etch stop and passivation materials are at least partially removed from the component structure. The illustrated steps can, for example, be directly linked to a cyclic process of the method's operation. The sacrificial region can be removed, for example, by means of an etching process suitable for removing silicon material. The etching process can, for example, be an isotropic plasma etching process using sulfur hexafluoride (SF6) or a vapor-phase etching process using xenon difluoride (XeF2). Here, the removal of the sacrificial region is limited by the surface passivation level of the trench structure, while the etch process is limited in the vertical direction via the etch stop region of the respective substrate surface. The material bond between two substrate planes, achieved via material layers, particularly those containing silicon material, can form a vertical etch channel for the sacrificial region via the substrate plane.

[0027] The present invention also relates to a microelectromechanical component structure having a first substrate having a base surface and at least one vertical functional region extending substantially perpendicular to the base surface, wherein the vertical functional region extends across a material layer disposed on the base surface and across a second substrate disposed on the material layer. This component structure is characterized by its particularly simple and efficient manufacture. By constructing the component structure based on a layered structure having at least two substrates disposed in the layered structure, it is possible to provide a structure with a high vertical extension dimension, high stability, and optionally very elongated structures, for example, with a width of less than 20 μm, and functional regions with narrow tolerances, for example, less than 10 μm, less than 5 μm, or less than 2 μm. For example, the functional region can have a vertical extension dimension that can be greater than 100 μm. The component structure can be manufactured, in particular, by the methods described above. The component structure can, for example, have a rectangular cross-sectional profile.

[0028] According to one embodiment, the material layer may have a single-crystal silicon material. Thus, for example, in the case of a single-crystal first substrate and a single-crystal second substrate, a continuous single-crystal vertical structure can be provided in the layer structure by means of a single-crystal material layer.

[0029] According to one embodiment, the vertical functional region can extend across at least one additional material layer and across at least one additional substrate disposed on said additional material layer. This can provide a component structure with a very high vertical extension dimension of the component structure or the vertical extension dimension of the component structure's functional region.

[0030] The present invention also relates to a microelectromechanical device having a microelectromechanical component structure according to one of the above features, wherein the microelectromechanical component structure is at least sectionally formed with an extrusion structure for generating fluid pressure. The extrusion structure can be formed, for example, by at least one functional region of the component structure. In this case, for example, at least one functional region of the component structure can form a movable element of the extrusion structure, wherein a volume change can be induced in the component structure by activating the functional region, and fluid pressure can be generated by this volume change. It is possible with the proposed component structure to provide functional regions with high vertical extension dimensions and elongated structural forms, these functional regions having low stiffness and therefore being easily activated. With such functional regions, highly efficient fluid pressure generation with low energy consumption is possible. According to one embodiment, the device can be configured, for example, as a pump or valve for microfluidic applications. According to another embodiment, the device can be configured as an acoustic sound generator.

[0031] The present invention also relates to a microelectromechanical loudspeaker having the aforementioned microelectromechanical device, wherein the extrusion structure is configured to generate sound pressure as fluid pressure, and wherein the loudspeaker further comprises a signal processing unit for applying and processing signals from the microelectromechanical device. The extrusion structure can be formed, for example, by at least one functional region of a component structure. With the proposed component structure, it is possible to provide a functional region with a high vertical extension dimension and an elongated structural form. Due to the elongated, longitudinally extending structural form, the functional region has low stiffness and is easily actuated. The functional region can advantageously form vertically distributed sheets of the loudspeaker, through which it is possible to generate sound pressure with high sound quality and low energy consumption. The microelectromechanical loudspeaker can, for example, be implemented as a system-on-a-chip (SoC).

[0032] In a completely general sense, in the context of this application, the word “a / one” should not be understood as a quantifier unless otherwise stated, but rather as an indefinite article with the meaning of “at least one”. Attached Figure Description

[0033] This invention allows for different implementations and is further explained below with reference to embodiments having accompanying drawings. The following is illustrated schematically: Figure 1 :- A method for manufacturing a microelectromechanical component structure according to one embodiment; Figure 2a-2k :- A method for manufacturing a microelectromechanical component structure according to another embodiment; Figures 3a-3b :-according to Figure 2a-2k The microelectromechanical component structure manufactured by this method before and after the end process of this method; Figure 4:- Schematic diagram of a microelectromechanical loudspeaker with microelectromechanical devices. Detailed Implementation

[0034] Figure 1 The illustration shows the process of manufacturing, for example, in... Figure 3a and 3b The diagram illustrates a method 100 for constructing a microelectromechanical component structure 200 according to one embodiment. Method 100 includes a start process 110, a cycle process 120, and an end process 130. The component structure 200 has a first substrate 20 with a substrate surface 21. Figure 3a As shown, the vertical functional region F extends substantially perpendicular to the substrate surface 21. The vertical functional region F is demarcated from the adjacent sacrificial region O by a trench 70 that creates and passivates the surface. Figure 3b It is released by removing the sacrifice region O. As follows... Figure 1 Similarly, by applying at least one layer 22, a bonding surface 23 is formed on the substrate surface 21 of the first substrate 20. A second substrate 30 is applied to the bonding surface 23, in which vertical grooves 70 are formed. Using the proposed method, the microelectromechanical component structure 200 and functional regions F, having a large vertical extension and an elongated structural form, can be fabricated with simplified process technology. Furthermore, the proposed method allows for a high degree of configurational freedom in forming the functional regions F in the component structure 200.

[0035] Below, based on Figure 1Steps 1 to 12 shown further explain the method 100. The initiation process 110 begins in the first step 1 with the provision of a first substrate 20 having a substrate surface 21. In the second step 2, a first etch stop layer 22a is applied as a layer 22 onto the substrate surface 21 of the first substrate 20. In the third step 3, etch stop regions 24a spaced apart from each other are generated by structuring the first etch stop layer 22a. Subsequently, the method 100 proceeds to the cyclic process 120. In the fourth step 4, the gaps 25a between the spaced-apart etch stop regions 24a are filled with a material layer 22b to form a bonding surface 23. In an optional fifth step 5, a CMP process is applied to planarize the bonding surface 23. In the sixth step 6, a second substrate 30 is bonded to the formed bonding surface 23. The second substrate 30 has a substrate surface 31 facing away from the first substrate 20. Optionally, in the seventh step 7, the second substrate 30 is thinned by grinding and polishing. In step 8, a second etch stop layer 26 is applied to the substrate surface 31 of the second substrate 30. In step 9, the second etch stop layer 26 is structured such that etch stop regions 24b spaced apart from each other are formed. In step 10, a vertical trench 70 is introduced between the etch stop regions 24b of the second etch stop layer 26. According to the illustrated embodiment, the vertical trench 70 terminates at the etch stop region 24a of the first etch stop layer 22a. In step 11, a third etch stop layer 27 is applied, through which the trench 70 is simultaneously passivated with a passivation material 71. In step 12, the third etch stop layer 27 is structured to create etch stop regions 24c spaced apart from each other. Subsequently, the cycle 120 can be selectively repeated with the addition of other substrates, such as a third substrate 40, a fourth substrate 50, and a fifth substrate 60, as shown below according to the appendix. Figures 2a to 2k The explanation remains the same. Alternatively, it is conceivable that after each cycle, a termination process 130 is initiated, in which the functional region F is released by removing the sacrifice region O. For example, termination process 130 can be initiated when the functional region F of the component structure 200 reaches a predetermined target height.

[0036] according to Figures 2a to 2k Explain how a component structure 200 with a personalized configuration of functional area F can be manufactured by the proposed method 100 while running multiple cyclic processes 120.

[0037] exist Figure 2aAs can be seen, a first substrate 20 with a substrate surface 21 is provided, and a first etch stop layer 22a is applied and structured as layer 22 on the substrate surface 21. The structuring creates etch stop regions 24a spaced apart from each other, with gaps 25a between these etch stop regions.

[0038] Depend on Figure 2b It can be concluded that the gap 25a is filled by the material layer 22b and forms the bonding surface 23. The material layer 22b can be applied, for example, by deposition or growth of a single-crystal silicon layer. Through the growth process, a polycrystalline layer 80 can be generated on the etch stop region 24a of the first etch stop layer 22a. Optionally, the bond surface 23 is chemically mechanically polished immediately after the application of the material layer 22b to create a contour-compensated and smooth bond surface 23. Subsequently, in the wafer bonding method, the second substrate 30, in particular a silicon substrate, is attached to the bonding surface 23 through the substrate surface 31. Subsequently, optional back-side grinding of the second substrate 30 and chemical mechanical polishing of the second substrate surface 31 are performed to bring the second substrate 30 to the target layer thickness. Furthermore, the second substrate 30 is structured by applying trenches 70 in the second substrate 30, which release the sides of the functional region F and terminate on the etch stop region 24a of the first etch stop layer 22a.

[0039] exist Figure 2c As can be seen, a third etch stop layer 27 is applied to the substrate surface 31 of the second substrate 30, thereby passivating the surface of the trench 70 with a passivating material 71. Furthermore, the trench 70 is sealed on the substrate surface 31 of the second substrate 30 by the third etch stop layer 27. In addition, the third etch stop layer 27 is structured to construct etch stop regions 24c spaced apart from each other.

[0040] Depend on Figure 2d It can be concluded that, similar to targeting Figure 2b The described process involves applying another material layer 22b to create another bonding surface 23 and attaching a third substrate 40. Trench 70 is formed in the third substrate 40, terminating at the etch stop region 24c of the third etch stop layer 27. The trench 70 in the second substrate 30 and the trench 70 in the third substrate 40 are primarily arranged such that they transition into each other as vertically continuous trench 70s. However, in Figure 2d It can also be seen that the etch stop region 24c' is constructed as the horizontal boundary of the functional region F, such that the vertical trenches 70 of the second substrate 30 on the etch stop region 24c' are arranged offset from the vertical trenches 70 of the third substrate 40. Thus, it can be seen that almost any geometry of the functional region F can be configured through the etch stop layer and the passivated vertical trenches. Furthermore, in Figure 2dAs can be seen, adjacent functional regions F can also be structurally separated from each other through vertical trenches and horizontal etching stop regions 24c'. Thus, for example, electrically insulated functional regions F can be fabricated in the component structure 200 for the purpose of separating potential guides.

[0041] exist Figure 2e As can be seen, a fourth etch stop layer 28 has been applied to the third substrate 40, and thus passivates the surface of the trench 70 with a passivating material 71. The fourth etch stop layer 28 has been structured to construct additional etch stop regions and also creates another horizontal etch stop region 24c'.

[0042] exist Figure 2f As can be seen, the fourth substrate 50 is attached and structured by the vertical groove 70 in a manner similar to the steps described above.

[0043] exist Figure 2g As can be seen, the trench 70 in the fourth substrate 50 is passivated by the fifth etch stop layer 29, and a horizontal etch stop region 24c' is constructed by structuring the fifth etch stop layer 29. Furthermore, similar to the previous steps, the fifth substrate 60 is attached to the bonding surface 23 constructed on the fourth substrate 50.

[0044] exist Figure 2h As can be seen, the fifth substrate 60 is further structured by vertical trenches 70 passivated by passivating material 71 and another horizontal etch stop region 24c' of the sixth etch stop layer 29-2. Furthermore, a seventh etch stop layer 29-3 has been applied and structured on the back surface 21-2 of the first substrate 20 opposite to the substrate surface 21, and vertical trenches 70 have been generated and passivated in the first substrate 20, wherein the trenches 70 in the first substrate 20 establish connections to the vertical trenches 70 of the second substrate 30. Therefore, the component structure 200 can also be structured in the sacrificial region O and the functional region F in the region of the first substrate 20, and the outline of the sacrificial region O and the functional region F is established throughout the component structure 200. Figure 2h In the process, the desired target height of functional area F is reached, and method 100 can enter the termination process 130.

[0045] exist Figure 2i In the process, the sacrificial regions O accessible from the surface of the fifth substrate 60 of the second substrate 30, the third substrate 40, the fourth substrate 50 and the fifth substrate 60 are continuously removed by etching of the isotropic sacrificial layer.

[0046] exist Figure 2jIn this process, the sacrificial regions O of the second substrate 30, the third substrate 40, the fourth substrate 50, and the fifth substrate 60, which are accessible from the back surface 21-2 of the first substrate 20, are continuously removed by etching with an isotropic sacrificial layer. The functional region F is released by removing the sacrificial regions O.

[0047] exist Figure 2k In the process, the achievable passivation and etch-stop layers of component structure 200 are removed by HF vapor phase etching to fully release the functional region F.

[0048] exist Figure 3a and 3b As can be seen, the data before and after the termination process 130 of method 100 is based on... Figure 2a-2k The microelectromechanical component structure 200 was manufactured using the method described above. Figure 3a As can be seen, the component structure 200 is laid out according to the arrangement of vertical trenches 70 and horizontal etch stop regions 24c', which divides the component structure 200 into a sacrificial region O and a functional region F. The vertical trenches 70 and horizontal etch stop regions 24c' can be individually applied in each layer plane of the component structure 200 and connected to the trenches 70 and etch stop regions 24c' of other layer planes. This allows for a high degree of configurational freedom in the three-dimensional structure of the component structure 200.

[0049] exist Figure 3b The diagram shows examples of structural elements of component structure 200, which can be coupled with... Figure 3a The functional area F shown is manufactured. The first structural element 91 can be, for example, a movable three-dimensional structural element clamped along the line of sight. The second structural element 92 can be, for example, a segmented movable three-dimensional structural element clamped on both sides. The third structural element 93 can be, for example, a segmented three-dimensional structural element clamped along the line of sight, and each segment is independently movable. The fourth structural element 94 can be, for example, a fixed three-dimensional support structure clamped on both sides. The fifth structural element 95 can be, for example, a movable three-dimensional structural element suspended on one side. The sixth structural element 96 can be, for example, a horizontal connector of vertically staggered structures of the same potential. The seventh structural element 97 can, for example, form horizontal electrical insulation. The eighth structural element 98 can, for example, form vertical electrical insulation. Therefore, it can be seen that the component structure 200 can be manufactured with a high degree of configurational freedom according to the proposed method 100.

[0050] Figure 4A microelectromechanical loudspeaker 400 having a device 300 and a signal processing unit 410 is schematically shown. The device has a component structure 200 that at least partially forms an extrusion structure according to the features described above. The signal processing unit is connected to the device 300 via a signal connection 420 and is configured to apply and process signals from the microelectromechanical device 300. The extrusion structure of the component structure 200 of the device 300 is configured to generate sound pressure as fluid pressure and operates acoustically efficiently with low power consumption. The microelectromechanical loudspeaker 400 can be implemented as a system-on-a-chip (SoC).

Claims

1. Method (100) for producing a microelectromechanical component structure (200) with a first substrate (20) having a substrate surface (21) and with at least one vertical functional region (F) which extends essentially perpendicularly to the substrate surface (21), wherein, The at least one vertical functional region (F) is demarcated from the adjacent sacrificial region (O) by creating and passivating at least one vertical trench (70) and is released by removing the sacrificial region (O), wherein a bonding surface (23) is created on the substrate surface (21) of the first substrate (20) by applying at least one layer (22), and wherein a second substrate (30) is applied on the bonding surface (23), thereby creating at least one vertical trench (70) in the second substrate.

2. The method (100) of claim 1, wherein The bonding surface (23) of the first substrate (20) is generated by applying and structuring a first etch stop layer (22a) to form etch stop regions (24a) spaced apart from each other and by filling the gaps (25a) between the etch stop regions (24a) with a material layer (22b).

3. The method (100) of claim 2, wherein, The gap (25a) is filled with a single-crystal silicon material as a material layer (22b).

4. The method (100) according to any one of the preceding claims, wherein, The bonding surface (23) of the first substrate (20) is prepared for application of the second substrate (30) by chemical and / or mechanical processing.

5. The method (100) according to any one of the preceding claims, wherein, Another bonding surface (23) is formed on the substrate surface (31) of the second substrate (30) opposite to the first substrate (20), and another substrate (40) is applied to the bonding surface (23) of the second substrate (30), in which at least one additional vertical groove (70) is formed.

6. The method (100) according to claim 5, wherein, The process involves cyclically applying at least one layer (22) to the substrate surface (21, 31) of the substrate (20, 30, 40, 50, 60), creating a bonding surface (23), applying another substrate (30, 40, 50, 60), and creating and passivating at least one vertical trench (70) in the other substrate (30, 40, 50, 60) until the predetermined target height of the vertical functional region (F) is reached.

7. The method (100) according to any one of the preceding claims, wherein, The method (100) has a start process (110), a loop process (120), and an end process (130), wherein the start process (110) has the following steps: - Provide the first substrate (20) (1); - Apply a first etch stop layer (22a) to the first substrate (20) (2); and -Etching stop regions (24a) (3) are generated by structuring the first etch stop layer (22a) and spacing them apart from each other.

8. The method (100) according to claim 7, wherein, The cyclic process (120) has the following steps: - Fill the gaps (25a) between the etch stop regions (24a) spaced apart by a material layer (22b) to form a bonding surface (23) (4); - Bond a second substrate or another substrate (30, 40, 50, 60) to the formed bonding surfaces (23) (6); - Apply a second etch stop layer (26) to the second substrate or another substrate (30, 40, 50, 60) (8); -Etching stop regions (24b) (9) are generated by structuring the second etch stop layer (26) and spacing them apart from each other. - At least one vertical trench (70) (10) is formed between the etch stop regions (24b) of the second etch stop layer (26), especially up to the etch stop region (24a) of the first etch stop layer (22a). - Apply a third etch stop layer (27) and passivate the at least one trench (70) (11); and - By structuring the third etch stop layer (27), etch stop regions (24c) (12) are generated that are spaced apart from each other.

9. The method (100) according to claims 7 and 8, wherein, The termination process (130) has the following steps: - The functional region (F) is released by removing the sacrifice region (O).

10. A microelectromechanical component structure (200) having a first substrate (20) having a base surface (21) and having at least one vertical functional region (F) extending substantially perpendicular to the base surface (21), wherein, The vertical functional area (F) extends across a material layer (22b) disposed on the substrate surface (21) and across a second substrate (30) disposed on the material layer (22b).

11. The microelectromechanical component structure (200) according to claim 10, wherein, The material layer (22b) has a single-crystal silicon material.

12. The microelectromechanical component structure (200) according to claim 10 or 11, wherein, The vertical functional area (F) extends across at least one additional material layer (22b) and across at least one additional substrate (40, 50, 60) disposed on the additional material layer (22b).

13. A microelectromechanical device (300) having a microelectromechanical component structure (200) according to any one of claims 10 to 12, wherein, The microelectromechanical component structure (200) at least partially forms an extrusion structure for generating fluid pressure.

14. A microelectromechanical loudspeaker (400) comprising the microelectromechanical device (300) according to claim 13, wherein, The extrusion structure is configured to generate sound pressure as fluid pressure, and is provided with a signal processing unit (410) for applying and processing signals from the microelectromechanical device (300).

Images