Method for manufacturing a semiconductor component and support substrate for manufacturing a semiconductor component

Abstract

A method (600) for manufacturing a semiconductor component (100) having at least one exposed film portion is presented, the method (600) having the following steps: preparing a semiconductor material (102) having a support substrate (104) provided with a passivation layer (108), on which passivation layer (108) a film layer (110) having or consisting of a material whose structure and / or composition can be changed by water, in particular hydrolyzable, is disposed, the film layer (110) covering the semiconductor material on the opposite side of the passivation layer (108) by a protective layer (114); removing a part of the support substrate (104) under the use of a wet chemical method to obtain an exposed region of the passivation layer (108) within the structured region (130) of the semiconductor material (102); and exposing a part of the film layer (110) within the structured region (130) using a first dry etching step for etching the passivation layer and a second dry etching step for etching the protective layer to obtain the exposed film portion (140).

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for manufacturing a semiconductor component according to the main claim.

Background Art

[0002] Regarding the manufacture of semiconductor components provided with a film, from German Patent Application Publication No. 102011005249A1, an apparatus for converting mechanical energy into electrical energy and a manufacturing method thereof are known. Herein, the manufacture of a curved piezoelectric film is described.

[0003] From Japanese Unexamined Patent Application Publication No. 2013-160706, a flow rate detection device on a semiconductor substrate having an exposed sensor surface is known.

[0004] Regarding modern semiconductor components, frequently, high flexibility regarding material properties is a prerequisite, and as a result, for example, good deflection of light rays can be achieved in optical semiconductor components. A semiconductor component can be interpreted, within the meaning of the present invention, as a component manufactured on a semiconductor substrate as a support substrate, for example a semiconductor wafer, for example a silicon wafer. This can be a mechanical and / or optical component, where in some cases the semiconductor properties of this substrate may not be important for the function. This can be a mechanical component, an optical component, a component for electromagnetic waves in the NIR region, visible region, UV region, EUV region or X-ray region. Such semiconductor components can be manufactured using typical technologies of the semiconductor industry. However, in this case, the problem is that some advantageous material properties partly belong to material types that are difficult to process. For example, a material can have good and desirable material properties such as a predetermined refractive index, and this material can interact particularly advantageously at the interface with other materials such as air, thereby enabling particularly good deflection or shaping of electromagnetic radiation. At the same time, this material itself may be, for example, water-soluble or hydrolyzable, so that some process steps used in conventional semiconductor manufacturing methods cannot be used to process this type of material.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Based on this problem setting, a realization method is presented that enables improved processing and thus manufacturing of semiconductor components with improved properties.

Means for Solving the Problems

[0006] This problem is solved by the subject matter of the main claim.

[0007] According to the approach presented herein, a method for manufacturing a semiconductor component with at least one exposed film portion is presented, where in this case the method has the following steps: - A step of preparing a semiconductor material having a support substrate provided with a passivation layer, on which a film layer having or consisting of a material whose structure and / or composition can be changed by water, in particular hydrolyzable material, is disposed, and this film layer is covered by a protective layer on the opposite side of the passivation layer; a step of preparing a semiconductor material; - A step of removing a part of the support substrate under the use of a wet chemical method to obtain an exposed region of the passivation layer within the structured region of the semiconductor material; and - A step of exposing a part of the film layer within the structured region by using a first dry etching step for etching the passivation layer and a second dry etching step for etching the protective layer to obtain an exposed film portion (140).

[0008] The support substrate can be interpreted as, for example, a conventional substrate, such as a substrate made of silicon. This support substrate may be provided with a passivation layer containing, for example, silicon nitride or made of such a material. The film layer can be interpreted as a layer having or consisting of a material that has particularly favorable properties with respect to its optical behavior, but whose structure and / or composition can be changed by water, particularly hydrolyzable. For example, when this material comes into contact with water or the layer made of this material is crushed or cracked, the mechanical structure of this material can deteriorate. Hydrolysis can be interpreted as the intervention between water molecules, whereupon the material can precipitate or crystallize again during the evaporation or volatilization of water. However, during hydrolysis, this material may also be chemically decomposed by contact with water. Aluminum nitride can be hydrolyzed, for example, under the formation of ammonia. The protective layer can be interpreted in this specification as covering the film layer. Here, a protective layer and a passivation layer preferably made of a water-insoluble material or a material whose structure and / or composition cannot be changed by water or containing such a material can ensure that the film layer is liquid-tightly sealed from the environment of the semiconductor component (for example, excluding the corners on the side surface of the wafer). In this way, it can be ensured that the film layer is not damaged during the processing or structuring of the support substrate or the region of the semiconductor component, and thus the semiconductor component to be manufactured is not destroyed. The wet chemical method can be interpreted as one process step or a plurality of process steps of a wet etching method or a wet cleaning method using a liquid etchant and / or a cleaning agent to introduce a structure into a semiconductor material or to clean the surface of a semiconductor material. The dry etching method can be interpreted as a process step of structuring a semiconductor material using a physical or mechanical removal method or using a gaseous etchant. Furthermore, the first and second dry etching steps can be carried out using the same dry etching method and / or in one process step, but this is not necessary.Similarly, it is preferable to perform two dry etching steps that are successively carried out on one side of the semiconductor component each time. Also, the order of the steps of preparing, removing, and exposing can preferably be carried out in the order given, and the first and second dry etching steps are carried out as partial steps of the exposing step and may be carried out in any order.

[0009] The approach proposed in this specification provides the advantage that, by using various etching methods or cleaning methods in various processing stages, it is guaranteed to keep the film layer sensitive to the etching material or cleaning material used in one of the process steps as intact as possible. In this way, it is also possible to use a material that is extremely advantageous for the function of the semiconductor component to be manufactured for the film layer. Therefore, the approach proposed in this specification enables remarkable flexibility when using various materials having extremely advantageous characteristics for the desired intended use of the semiconductor component.

[0010] One embodiment of the approach proposed herein is advantageous when, in the preparation step, a semiconductor material with a protective layer having a cover layer forms a layer stack as the protective layer, where the material of the protective layer is different from the material of the cover layer, and in particular the material of the cover layer has a reflective material and / or metal. Such an embodiment provides the advantage that the structuring of this protective layer can be extremely flexible due to the different materials of the layers of the protective layer, so that a flexible design of the exposed film layer can also be achieved in subsequent process steps. By using a reflective material for the cover layer, for example, the desired optical properties of the finished semiconductor component can also be realized. Also, according to one embodiment, this method can further include a step of structuring the protective layer, which is carried out before the second dry etching step, in particular before the step of removing a part of the support substrate, where the protective layer is at least partially, in particular under the use of an auxiliary mask, removed by one of the etching methods (e.g., the dry etching method used in the first or second dry etching step) or another etching method (e.g., a further or different dry etching method) to expose the cover layer.

[0011] According to another embodiment of the approach proposed herein, in the structuring step, a part of the support substrate can be removed within the structured region. Such an embodiment of the approach proposed herein provides the possibility of preparing a semiconductor material or a semiconductor component so that only a dry etching method can be used in the subsequent exposing step using known efficient processing steps. In this way, by pre-treating the semiconductor material, it can be avoided that in some cases the already exposed surface of the film layer is damaged by an etching agent or a cleaning agent that is too aggressive with respect to the material of the film layer.

[0012] An embodiment of the approach proposed herein, which implements a process of structuring such that the membrane layer is sealed against an etchant or a cleaning agent of a wet chemical method by means of a passivation layer and at least a part of a protective layer, is particularly advantageous. This type of embodiment offers the advantage that the membrane layer is reliably protected against an etchant of a wet chemical method, thereby avoiding damage to the membrane layer.

[0013] According to another embodiment of the approach proposed herein, in the step of exposing, at least a part of the passivation layer and the protective layer can be removed by means of a dry etching method. This type of embodiment of the approach proposed herein offers the advantage that a dry etching method can be applied already when initially exposing the membrane layer, thereby enabling the membrane layer to be protected as well as possible or structured efficiently.

[0014] Particularly delicate and efficiently designed semiconductor components for their intended use can be manufactured even when the film layers are not only exposed but also structured. For this purpose, for example, through-holes can be introduced into the film layer, for example, to enable the realization of a damper for electromagnetic radiation or an optical structure, such as an aperture structure within the film layer in the exposed film portion. Such an aperture structure can have through-holes with a diameter larger than the design optical wavelength of the component in order to form a conventional aperture. Thus, according to a particularly preferred embodiment, in order to obtain a perforated and exposed film portion, in the step of exposure, the film layer can be at least partially removed, and in particular in this case, the structured region of the protective layer and / or the coating mask applied on the protective layer and / or on the cover layer can be used as an etching mask. Such perforations can have perforation holes with a diameter larger than the design optical wavelength of the component in order to form a conventional aperture. It is also possible to provide perforation holes with a diameter smaller than the design optical wavelength of the component in order to generate evanescent light waves or to act as a short-pass filter. The perforated film portion may represent a diffraction grating. It should be noted that in the context of the present invention, light can also be interpreted as EUV radiation (XUV in English), UV radiation, visible light, and infrared light. The optical function (design optical wavelength) of the component may be envisaged for each of the wavelength regions mentioned.

[0015] Furthermore, according to another embodiment of the approach presented herein, in the step of structuring and exposing, within a passage region laterally adjacent to the structured region, the membrane layer, the support substrate, the protective layer, the masking layer, and the passivation layer can be removed such that an opening is formed and fragments of the membrane layer do not protrude within this opening. Such an embodiment of the approach proposed herein provides the advantage that, using the method presented herein, another region of the semiconductor material where the exposed portion of the membrane layer is not required can also be structured. In this way, the structuring of the semiconductor material or semiconductor component can be carried out compactly with fewer working steps, thereby reducing the manufacturing cost and manufacturing time.

[0016] Furthermore, in the structuring step, it is particularly preferred to apply a holding material on a portion of the passivation layer exposed within the passage region and, in the exposing step, to remove the holding material within the passage region after removing the support substrate and the passivation layer in order to form an opening. The holding material can be interpreted, for example, as a plastic material, such as a photoresist, which can also be used to introduce structures into different layers of the semiconductor material. Also, this holding material may be applied together with another material on the surface of the semiconductor material or semiconductor component. For example, by using a semiconductor material applied directly on the passivation layer, flakes or fragments of the layer to be removed are prevented from uncontrollably falling into the processing space and causing defects in subsequent steps. Rather, this type of fragment that may occur by continuously reducing the thickness of the layer to be removed can be supported by the holding material or held by material bonding, enabling complete removal or dissolution of this fragment. In this case, the holding material may preferably be applied on the passivation layer on the side opposite the substrate within the extent of the intended passage region.

[0017] In the exposing step, an embodiment of the approach proposed herein, which forms an opening so as to have a diameter larger than that of the opening in the exposed region of the film layer, can also be used very flexibly. Such an embodiment provides the advantage that structures of different dimensions can be introduced into the semiconductor material using a unified method or process, so that the desired functions can be efficiently realized in the semiconductor member.

[0018] A semiconductor component having particularly advantageous properties can be realized, in particular, by preparing a semiconductor material in which the passivation layer and / or the masking layer has at least partially silicon nitride, and / or the film layer has at least partially aluminum nitride, germanium oxide and / or aluminum oxide, and / or the cover layer contains a metal, in particular chromium, and / or the protective layer contains silicon and / or silicon nitride in the preparation step. In this way, a semiconductor component that is particularly advantageously designed for optical applications can be realized.

[0019] Particularly advantageously, in order to implement the various steps of the approach proposed herein, in the structuring step, a wet chemical method can be used, such as implementing a wet etching method under the use of potassium hydroxide or tetramethylammonium hydroxide as an etchant and / or implementing a wet chemical cleaning method and / or in the exposing step, an embodiment can be used in which a dry etching method is implemented under the use of a physical dry etching method, a chemical dry etching method and / or a physical-chemical dry etching method.

[0020] Preferably, the thickness of the film layer can be 5 nm to 1000 nm, particularly preferably 10 nm to 500 nm, and most preferably 50 nm to 200 nm. Preferably, the lateral spread of the exposed area of the film can be 50 μm to 5000 μm, particularly preferably 100 μm to 500 μm. This film may be perforated, for example, to have a hole pattern with a lateral hole spacing of 50 nm to 5000 nm, preferably 100 nm to 1000 nm. This film can be used, for example, to absorb and / or diffract electromagnetic radiation.

[0021] Furthermore, the structured region of the semiconductor material has an edge, and the normal of the edge has an angle of less than 60°, particularly 54.7°, with respect to the surface normal of the support substrate. In particular, when this semiconductor material is a single crystal and this edge is formed by an etch-resistant crystal plane, one embodiment of the approach presented in this specification is preferred. For example, a silicon wafer having a {100} surface can be used. When this edge is formed by the {111} crystal plane and equivalent crystal planes, this angle can be 54.74°.

[0022] Variations of this method may be implemented, for example, in the form of software or hardware, or in a mixed form of software and hardware, for example, as control instructions in a control device or apparatus.

[0023] The approach presented in this specification further achieves an apparatus formed to implement, control, or transform the steps of the variations of the method presented in this specification in corresponding equipment. This implementation variation of the present invention in the form of an apparatus can also quickly and efficiently solve the problems underlying the present invention.

[0024] For this purpose, the device can have at least one arithmetic unit for processing signals or data, at least one storage unit for storing signals or data, at least one interface for sensors or actuators for reading sensor signals of sensors or outputting data signals or control signals to actuators and / or at least one communication interface for reading and outputting data embedded in a communication protocol. The arithmetic unit can be, for example, a signal processor, a microcontroller, etc., and the storage unit can be a flash memory, an EEPROM or a magnetic storage unit. The communication interface can be formed to be wirelessly and / or wiredly connected to read or output data, and a communication interface capable of reading or outputting wiredly connected data can read this data electrically or optically from a corresponding data transmission line or output it into a corresponding data transmission line.

[0025] The device can be interpreted in this specification as an electrical device that processes sensor signals and outputs control signals and / or data signals depending thereon. The device can have an interface that can be formed according to hardware and / or software. In the case of a hardware-based formation, this interface can be, for example, part of a so-called system-ASIC that includes various functions of the device. However, this interface can also be a separate integrated circuit or at least partially consist of separate components. In the case of a software-based formation, this interface can be, for example, a software module that exists on a microcontroller in addition to other software modules.

[0026] A computer program product or program code that may be stored in a machine-readable carrier or storage medium, such as a semiconductor memory, a hard disk memory, or an optical memory, and is used for executing, transforming, and / or controlling the steps of the method according to one of the above-described embodiments is also advantageous, particularly when this program product or program is executed on a computer or device.

[0027] Examples of the approach presented in this specification are shown in the drawings and will be described in more detail in the following description.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0029] In the following description of the preferred embodiments of the present invention, for members shown in different figures and acting similarly, the same or similar reference numerals are used, and repeated descriptions of these members are omitted.

[0030] FIG. 1 shows a plurality of partial views depicted as FIGS. 1A-1I, each showing a cross-sectional view of a semiconductor component 100 manufactured according to an embodiment after different process steps.

[0031] In FIG. 1A, first, a semiconductor material 102 is shown in the form of a stack of a plurality of layers. In this case, the semiconductor material 102 includes a support substrate 104 made of or including, for example, silicon. The semiconductor substrate 104 further includes a lower masking layer 106 and a passivation layer 108, and this passivation layer has or includes, for example, silicon nitride (Si 3 N 4 ). The masking layer 106 and the passivation layer 108 can be formed on the support substrate 104, for example, in the same manufacturing step. On the passivation layer 108, a film layer 110 including or consisting of, for example, a water-soluble material is disposed. Separately or additionally, the film layer 110 can be or consist of a material whose structure and / or composition can be changed by water, particularly a hydrolyzable material. On the film layer 110, a protective layer 112 including, for example, a protective layer 114 and a cover layer 116 disposed on the protective layer 114 is disposed. This protective layer 114 has a silicon-based semiconductor material herein and may be formed as an etch stop layer. The cover layer 116 can include or consist of, for example, a reflective material and / or a metal, such as chromium.

[0032] In a first processing step, for example, the structuring of the cover layer 116, for example, a reflective material, is performed. For this purpose, for example, a photoresist can be used, and this photoresist is exposed according to the structure introduced into the cover layer 116. For the structuring of the cover layer 116, a wet etching method can be used, and separately or additionally, a dry etching method can also be used.

[0033] FIG. 1B shows a cross-sectional view of the semiconductor component 100 in the state after the implementation of the above-described method steps.

[0034] Subsequently, according to this embodiment, the structuring of the masking layer 106 is carried out, for example, again under the use of a photoresist to be exposed and / or under the use of a wet etching method or another dry etching method different therefrom.

[0035] FIG. 1C shows a cross-sectional view of the semiconductor component 100 in the state after the implementation of this method step.

[0036] In a further method step, in order to realize various lattice types within the semiconductor component 100, structuring is carried out under the use of a photoresist as the etching mask 120. Thereby, the substrate lattice type 122 and on the other hand, the film lattice 124 can be structured within another region.

[0037] FIG. 1D shows a cross-sectional view of the semiconductor component 100 in the state after the implementation of this method step.

[0038] According to the embodiment shown in FIG. 1 for the manufacture of the semiconductor component 100, in a further method step, etching is carried out through the support substrate 104 under the use of a wet etching method. In this case, by using the wet etching method, side surfaces that are inclined obliquely into the support substrate can be formed through the openings of the masking layer 106 instead of trenches, which is made possible by the corresponding orientation of the crystal structure of the support substrate 104 by using the wet etching method. The formation of this kind of side surface is extremely advantageous for optical applications, as will be explained in more detail below. Then, etching is carried out until the back surface of the passivation layer 108, which functions as a stop layer for the wet etching method, is exposed. In this way, it is possible to avoid the water-soluble or water-sensitive film layer 110 being attacked by the wet etching method and thereby being damaged or destroyed.

[0039] FIG. 1E shows a cross-sectional view of the semiconductor component 100 in the state after the implementation of this method step. At the same time, this state of the semiconductor component 100 is the final state in this embodiment of the manufacturing that can be processed by the steps of the wet etching method. The subsequent steps are carried out under the use of the dry etching method in order to avoid damage or destruction of the film layer 110 made of or containing this water-soluble material.

[0040] In subsequent steps, the sacrificial layer can be removed, and this sacrificial layer is, in the embodiments of this specification, the exposed portion of the passivation layer 108 on the back side of the support substrate 104 and is also the portion of the protective layer 114 not covered by the photoresist and / or the cover layer 116 as the etching mask 120. The dry etching method is used for this removal because now the film layer 110 is exposed within the structured region 130 and within the through region 132. Due to the use of the process steps of the wet etching method, in this state, the film layer 110 is also attacked and damaged. Therefore, according to the approach presented in this specification, only the use of the dry etching method is allowed for the processing of the semiconductor component 100 after this method step.

[0041] FIG. 1F shows a cross-sectional view of the semiconductor component 100 in the state after the implementation of this method step.

[0042] Subsequently, in a further method step, for example, the removal of the membrane layer 110 within the passage region 132 can be carried out, so that here a wide opening 136 penetrating the semiconductor component 100 is produced. Furthermore, within the structured region 130, the exposed membrane layer 110 can also be removed through the structured protective layer 112, in particular through the structured protective layer 114 and the structured cover layer 116, which can be realized, for example, by a dry etching method acting from above. In this way, the membrane layer 110 containing a water-soluble or water-sensitive material can be structured as desired. At the same time, extremely fine structures, such as holes 138 within the structured region 130, for example, can also be realized within the membrane layer 110, which, for example, enables the formation of the subsequently produced exposed membrane layer 110 as a movable element.

[0043] Figure 1G shows a cross-sectional view of the semiconductor component 100 in the state after the implementation of this method step.

[0044] Furthermore, in a subsequent step, the region of the protective layer 112 not covered by the etching mask 120, for example, the region not covered by the protective layer 114 and the cover layer 116, is (dry) etched or removed, thereby producing an exposed membrane portion 140 of the membrane layer 110 having, for example, a fine structure, such as a through-hole 138. The diameter of this through-hole 138 can also be made significantly smaller than the opening 236 within the passage region 132.

[0045] Figure 1H shows a cross-sectional view of the semiconductor component 100 in the state after the implementation of this method step.

[0046] Finally, in a subsequent step, the removal or (dry) etching of the etching mask 120 and, optionally, the separation of individual parts of the semiconductor component 100 are carried out.

[0047] Figure 1I shows a cross-sectional view of the semiconductor component 100 in the state after the implementation of this method step.

[0048] Accordingly, the partial view of FIG. 1 shows an example of a process procedure for manufacturing a self-standing, moisture-sensitive, structured film using a sacrificial protection layer and standard CMOS process steps. During all critical steps, sensitive layers such as film layer 110 are protected, thereby enabling the use of wet and thus low-cost replacement process steps.

[0049] Accordingly, using the approach presented herein, it is possible to manufacture an ultrathin, self-standing, structured film as film layer 110 made of a sensitive layer material by a wet method. In this way, it is possible to efficiently realize the manufacture of a self-standing ultrathin film that generally requires many wet chemical process steps for wet chemical methods such as lithography and wafer cleaning. To manufacture a self-standing film, the entire wafer is generally etched by dry etching or wet etching. Dry etching methods such as DRIE (deep reactive ion etching) produce a substantially vertical etching profile through the wafer, while wet etching methods may also produce an inclined etching profile within the etched grooves. For optical applications, an inclined V-shaped sidewall using wet etching is preferred to transmit light with a high NA (numerical aperture) through the film without shading on the sidewalls of the wafer holes. Of course, the use of wet etching methods is difficult or impossible when the use of a film material sensitive to wet chemistry is required. For example, aluminum-based or germanium-based materials may be water-soluble and are thus not suitable for most wet methods. In contrast, the approach presented herein provides a process procedure that enables the manufacture of substantially all self-standing film materials. Furthermore, a method for manufacturing a structured film is described.

[0050] The production of free-standing membranes is a widespread technology, for example, for MEMS products or optical sensors. Usually, a robust material such as SiN or metal is used as the membrane material or the material for the membrane layer 110. However, depending on the application, the use of more sensitive materials is also desirable. For example, GeO, AlN, or Al x O y are good candidates for transmissive UV and EUV applications based on a good refractive index match compared to vacuum. However, since these materials are soluble in water, wet process steps are not directly possible. Here, a method is presented that can now produce a free-standing membrane consisting of almost all structured hygroscopic materials and having sloping sidewalls of holes etched through the wafer. These sidewalls consist of various sacrificial layers that protect the sensitive layer of the membrane layer 110 from the wet environment. Using this approach, it is possible to structure the membrane and enable a reflective material suitable for sensor purposes in the VIS region. For the accuracy of structuring, there are no limitations other than the resolution limits of the lithography tools and etching tools used. Here, the minimum structure size <200 nm within the resolution limit of the tools is shown.

[0051] The approach presented in this specification can be particularly preferably used for the production of free-standing ultrathin membranes made of materials suitable especially for the UV region and EUV region. This material, especially AlN, is water-soluble or hydrolyzable especially in the case of thin layers and is not robust in the commonly used cleaning chemicals. The proposed process flow avoids these limitations.

[0052] The proposed process flow also enables, in principle, the use of each depositable and structurable material as the membrane layer, resulting in high flexibility in the design of semiconductor components.

[0053] The proposed process will be described based on the processing steps of the semiconductor component shown in the partial view of FIG. 1. This process includes various standard process steps such as coating, lithography, cleaning, wet etching, and dry etching. The use of the proposed process route enables the implementation of more wet cleaning steps, thereby improving the overall quality of surface defects. In particular, it is generally possible to at least partially utilize important steps of wet etching for the production of the film.

[0054] An important aspect of the proposal presented herein is the use of a protective layer below (SiN) and above the moisture-sensitive layer during all wet process steps. These protective layers are ultimately removed by etching. This layer stack is selected such that individual layers can be selectively etched without etching other masking layers and / or protective layers. Another advantage of the proposed approach or layer stack is that the optical reflectivity can be adjusted by the selected material and / or layer thickness. For example, the introduction of the protective layer offers the possibility of reducing the reflectivity to almost zero with, for example, green light or achieving the maximum reflectivity by simply changing the layer thickness.

[0055] In the proposed process flow, the steps between the processing steps shown in FIGS. 1F and 1G are challenging. During the etching through the last self-supporting layer to create a large hole such as within the region of the via opening 136, this layer is gradually thinned. If the remaining layer is too thin (on the order of a few nanometers) to remain intact, this film or the film layer 110 herein will break and curl up to form spangles before the etching process is completed. These fragments, which can consist of moisture-sensitive materials, act as an unwanted masking layer in subsequent processes. For this reason, an optimized process flow has been developed to avoid these spangles through large openings.

[0056] Figure 2 shows, in a plurality of partial views, the respective cross-sections of the semiconductor component 100 manufactured according to the embodiment at various process steps. Starting from the processing stage of the semiconductor component 100 shown in Figure 1C, in the first intermediate step shown on the right, first, a shading mask 200 is used, and this shading mask is used for the removal of the protective layer 114 within the passage region 132 by a dry etching method in a dry etching step. In this way, the film layer 110 is exposed within the passage region 132. In subsequent process steps, this exposed film layer 110 is removed by a wet etching method or a dry etching method. Next, continue with the procedure according to the figure of Figure 1D, but also apply it onto the upper passivation layer 108 where the etching mask 120 is additionally exposed. Therefore, in subsequent steps, especially in the transition from the processing state between the semiconductor components 100 shown in Figures 1F and 1G, the upper passivation layer 108 (and not the film layer 110 that has already been pre-removed within the passage region 132) is guaranteed not to collapse and become spangles that may act as defective optical masks.

[0057] Therefore, Figure 2 shows a schematic view (partially) optimized to avoid spangles arising from the moisture-sensitive layer with large openings. Two new process steps are included for selectively etching the layer within the region of the large film opening 136, that is, within the passage region 132. All other process steps are the same as or very similar to the previous process flow in Figure 1.

[0058] Two additional process steps (shown on the right in Figure 2) are used for the selective removal of the moisture-sensitive layer at the large opening. A variety of etching methods can be used. In this process schematic, a shadow mask is used exemplarily to open the buffer layer. All other processes essentially correspond to the procedures described in advance in Figure 1. The only difference is that a slightly adapted photomask is used in the step brought about for the semiconductor component according to Figure 1D in order to keep the large opening closed by the photoresist as the etching mask 120. This improved process flow makes it possible to replace the important step of etching through the self-supporting moisture-sensitive layer with a process step of etching against the thick (self-supporting) photoresist. Thereby, it is possible to avoid the occurrence of spangles or flakes made of extremely thin and / or moisture-sensitive materials that are broken, for example, during processing.

[0059] As an example for the moisture-sensitive film material, the feasibility of this process procedure can be shown under the use of aluminum nitride (AlN). AlN not only dissolves in water and / or may decompose while forming ammonia upon the action of water, which is a major challenge for wet process steps. In order to obtain a flat, self-supporting AlN film, the layer stress is adjusted to a tensile stress of several 100 MPa. In this example, silicon or silicon nitride was used as the protective layer. Chromium was used as the masking layer and the reflective layer, or as the cover layer 116.

[0060] Figure 3 shows a schematic cross-sectional view of the layer stack used as the starting material 102 for the semiconductor component 100, where an exemplary layer stack for the production of a self-supporting water-soluble AlN film is detailed. The AlN layer is placed under tensile stress. The masking layer 106 and the passivation layer 108 are exemplarily designed as etch stop layers and may exemplarily contain a Si 3 N 4 layer with a thickness of, for example, 100 nm. The film layer 110 may have AlN with a thickness of, for example, 100 nm. The protective layer 114 has a thickness of, for example, 50 nm and is SiNx It may be formed as, for example, the cover layer 116 may be formed as a metal layer made of, for example, chromium with a thickness of, for example, 100 nm.

[0061] The proposed process flow avoids exposing water-soluble AlN to a liquid process step. The desired V-shaped trenches through the wafer are etched with diluted KOH (potassium hydroxide) or TMAH (tetramethylammonium hydroxide). As a final result, various types of markers can be manufactured, namely gratings structured in chromium for reflective sensor purposes and gratings structured in a self-standing AlN film for transmission purposes. Furthermore, large openings can be provided, for example, for cleaning purposes.

[0062] FIG. 4 shows a cross-sectional view of a wafer structured as a semiconductor component 100 consisting of a reflective Cr marking, a large opening enabling access to the back of the wafer, and a transmissive marker in contact with the self-standing AlN film.

[0063] In this case, the lateral dimensions of the Cr markers as well as the structured holes in the AlN film are limited only by the resolution limit of the lithography tool in combination with the dry etching tool. Structures with a lateral dimension of about 100 nm can be realized. Similar results are achieved when using Al 2 O 3 which is sensitive to many wet cleaning mixtures as the film material. A typical SEM image (scanning electron microscope) of the structured self-standing AlN film is shown in the following drawing.

[0064] FIG. 5 shows a diagram of an SEM image of a structured AlN film 110 manufactured by the proposed process flow. These circles are holes in the passage region 132 within the AlN film, and these holes enable a free optical path through the film 110 and the entire wafer 104.

[0065] FIG. 6 shows a flowchart of a method 600 for manufacturing a semiconductor component having at least one exposed film portion. The method includes a step 610 of providing a semiconductor material having a support substrate with a passivation layer, on which a film layer having or consisting of a material whose structure and / or composition can be changed by water, in particular a hydrolyzable material, is disposed, and this film layer is covered by a protective layer on the side opposite to the passivation layer. Further, the method 600 includes a step 620 of removing a part of the support substrate under the use of a wet chemical method to obtain an exposed region of the passivation layer within the structured region of the semiconductor material. Finally, the method 600 includes a step 630 of exposing a portion of the film layer within the structured region using a first dry etching step for etching the passivation layer and a second dry etching step for etching the protective layer to obtain the exposed film portion.

[0066] FIG. 7 shows a block diagram of an apparatus 700 for manufacturing a semiconductor component. The apparatus 700 includes a unit 710 for providing a semiconductor material having a support substrate with a passivation layer, on which a film layer having or consisting of a water-soluble material is disposed, and this film layer is covered by a protective layer on the side opposite to the passivation layer. Further, the apparatus 700 includes a unit 720 for structuring the protective layer under the use of a wet etching method to obtain a structured region of the semiconductor material. Finally, the apparatus 700 includes a unit 730 for exposing a portion of the film layer within the structured region under the use of a dry etching method to obtain the exposed film portion.

[0067] In summary, it can be noted that this specification presents an advantageous approach for manufacturing structured self-supporting membranes. A process flow is presented that allows the use of materials that are not robust in the chemicals conventionally used for cleaning and etching, particularly in water. This broad material selection allows the use of membranes having a low refractive index and thereby low dispersion. A process flow optimized to allow large openings without spangles, which typically occur during through-etching of the membrane, is also presented.

[0068] The overall etching step can be made selective with respect to the respective masking layer and etch stop layer. Despite the use of a protective layer, small defects increase the risk of causing unwanted undercut etching or contact etching.

[0069] Now, almost all materials that can be deposited and structured can be used as alternative membrane layers, and the flexibility of the approach presented in this specification is improved compared to conventional process steps.

[0070] The process flow according to the invention can be carried out equally advantageously for a typical MEMS membrane with sensitive materials. Furthermore, the possibility of sensitive materials as membrane layers, which was not achievable with conventional methods, is opened up.

Claims

1. A method (600) for manufacturing a semiconductor component (100) having at least one exposed film portion, the method (600) comprises the following steps: Step (610) of preparing a semiconductor material (102) having a support substrate (104) provided with a passivation layer (108), wherein a film layer (110) having or consisting of a material whose structure and / or composition can be changed by water, in particular hydrolyzable material, is disposed on the passivation layer (108), and the film layer (110) is covered by a protective layer (114) on the opposite side of the passivation layer (108); Step (620) of removing a portion of the support substrate (104) using a wet chemical method in order to obtain an exposed area of ​​the passivation layer (108) within the structured region (130) of the semiconductor material (102); and Step (630) to expose a portion of the film layer (110) within the structured region (130) by using a first dry etching step for etching the passivation layer and a second dry etching step for etching the protective layer in order to obtain the exposed film portion (140). A method for manufacturing semiconductor components, comprising:

2. The method (600) of claim 1, wherein in the preparation step (610), a semiconductor material (102) is prepared in which the protective layer (114) having a cover layer (116) forms a layer stack as a protective layer (112), the material of the protective layer (114) is different from the material of the cover layer (116), in particular the material of the cover layer (116) has a reflective material and / or a metal, the method (600) further includes a step of structuring the protective layer (112) before the second dry etching step, in particular before the step (620) of removing a portion of the support substrate, the protective layer (114) is exposed by removing the cover layer (116) by an etching method used in the first dry etching method or the second dry etching method or another etching method, at least partially, in particular under the use of an auxiliary mask.

3. The method according to claim 1 (600), characterized in that, in the structuring step and the exposure step (630), the film layer (110), the support substrate (104), the protective layer (114), and the passivation layer (108) are removed in a passing region (132) laterally adjacent to the structured region (130) such that an opening (136) is formed through the semiconductor component (100), and in particular, the portion of the film layer (110) does not protrude within the opening.

4. The method according to claim 3 (600), characterized in that, in the structuring step, a retaining material (210) is applied to the portion of the passivation layer (108) exposed within the passage region (132) in order to avoid contamination by peeling of material residue of the passivation layer to be removed, and in the exposure step (630), the retaining material (210) is removed within the passage region (132) after the support substrate (104) and the passivation layer (108) have been removed in order to form the opening (136).

5. The method according to claim 3 (600), wherein in the exposure step (630), the opening (136) is formed such that the opening (136) has a larger diameter than the opening (138) in the exposed region (140) of the film layer (110).

6. The method according to claim 2 (600), characterized in that in the structuring step, a wet etching method is carried out using potassium hydroxide or tetramethylammonium hydroxide as an etching agent as a wet chemical method, and / or in the exposure step (630), the first dry etching step and / or the second dry etching step are carried out using a physical dry etching method, a chemical dry etching method and / or a physicochemical dry etching method.

7. The method according to claim 1 (600), characterized in that multiple semiconductor components are manufactured simultaneously on the support substrate.

8. The method according to claim 1 (600), characterized in that, prior to the step (630) of exposing a portion of the membrane layer (110), at least one cleaning step using a water-containing cleaning agent, particularly a wet chemical cleaning method, is planned.

9. The method according to claim 1 (600), characterized in that, in the exposure step (630), the film layer (110) is at least partially removed in order to obtain the perforated and exposed film portion (140), and in particular, a coating mask (120) applied to the structured region (130) of the protective layer (114) and / or on the protective layer (114) and / or on the cover layer (116) is used as an etching mask.

10. The method according to claim 1 (600), characterized in that in the preparation step (610), a semiconductor material (102) is prepared, wherein the passivation layer (108) has at least partially silicon nitride, and / or the film layer (110) has at least partially aluminum nitride, germanium oxide, and / or aluminum oxide, and / or the cover layer (116) comprises a metal, in particular aluminum, or a transition metal, in particular a transition metal, titanium, nickel, chromium, tantalum, tungsten, and platinum, and / or the protective layer (114) comprises silicon and / or silicon oxide and / or silicon nitride.

11. The method according to claim 1 (600), wherein the structured region (130) of the semiconductor material (102) has a margin, the normal of the margin has an angle of less than 60°, particularly 54.7°, with respect to the surface normal of the support substrate, and in particular the semiconductor material is a single crystal, and the margin is formed by an etching-resistant crystal plane.

12. The method according to any one of claims 1 to 11 (600), characterized in that the film layer (110) has a thickness of 10 nm to 500 nm.

13. An apparatus (700) designed to perform and / or control the steps (610, 620, 630) of the method (600) according to any one of claims 1 to 11 within a corresponding unit (710, 720, 730).

14. A computer program configured to execute and / or control the steps of the method (600) according to any one of claims 1 to 11 when the computer program is executed on an arithmetic unit.

15. A support substrate (104) for manufacturing at least one semiconductor component (100) comprising at least one exposed film portion and a passivation layer (108) disposed on a first side, wherein a film layer (110) is disposed on the passivation layer (108), the film layer having or consisting of a material whose structure and / or composition is changeable by water, in particular hydrolyzable, and the film layer (110) is covered by a protective layer (114) on the opposite side of the passivation layer (108). -The protective layer (114) comprises silicon and / or silicon nitride, and together with the cover layer (116), the protective layer (114) forms a layer stack as a protective layer (112), the material of the protective layer (114) is different from the material of the cover layer (116), the cover layer (116) comprises a metal, and furthermore, an etching mask for wet etching the substrate is applied to the second side of the support substrate opposite to the first side of the support substrate (104).

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