DE102022107732A1 - Method for producing a layered structure, a layered structure and an acoustic wave component - Google Patents

Abstract

Various exemplary embodiments relate to a method for producing a layer structure, a layer structure and an acoustic wave component. According to various embodiments of the method for producing a layer structure, the method includes forming a first fluorine-free barrier layer, and forming a fluorine-doped silicon oxide layer on the first barrier layer, the first barrier layer being adapted to diffuse out fluorine from the fluorine -doped silicon oxide layer.

Description

Various exemplary embodiments relate to a method for producing a layer structure, a layer structure and an acoustic wave component.

Components made of silicon oxide can be used for temperature compensation in components. Such components can be, for example, filter elements such as acoustic wave filter elements, e.g. surface acoustic wave filters (SAW filters, Surface Acoustic Wave Filters) or substrate acoustic wave filters (BAW filters, Bulk Acoustic Wave Filters). . For example, a change in temperature of an acoustic wave filter element can lead to a change in the filter properties such as a shift in the filtered frequencies. Silicon oxide can be used to reduce thermal expansion of a filter element or its components and so the frequency properties of the filter element are more stable in the event of temperature fluctuations. With fluorine-doped silicon oxide, the temperature compensation properties are even more pronounced compared to pure silicon oxide. However, fluorine can diffuse out of fluorine-doped silicon oxide, which on the one hand affects the temperature compensation and on the other hand can corrode, for example, electrical contacts of a filter element. Furthermore, a component made of fluorine-doped silicon oxide, for example a layer, should be able to be produced with as little effort as possible.

According to various exemplary embodiments, a method for producing a layer structure includes forming a first fluorine-free barrier layer and forming a fluorine-doped silicon oxide layer on the first barrier layer, wherein the first barrier layer is designed to diffuse out fluorine from the fluorine-doped silicon oxide layer to reduce.

According to various embodiments, the method may further comprise forming a second fluorine-free barrier layer on the fluorine-doped silicon oxide layer, wherein the second barrier layer is configured to reduce the out-diffusion of fluorine from the fluorine-doped silicon oxide layer.

According to various embodiments, the method may further comprise forming one or more additional fluorine-doped silicon oxide layers and/or one or more additional barrier layers on the layer structure, wherein fluorine-doped silicon oxide layers and barrier layers are formed alternately on top of one another.

According to various embodiments, the first barrier layer, the second barrier layer, and/or one or more additional barrier layers may include or consist of one or more of the following materials: silicon oxide, silicon nitride, aluminum oxide, silicon oxynitride, carbon, diamond-like carbon (DLC), and/or silicon carbide . The materials may be present as pure materials or compounds or as doped materials or doped compounds.

The first barrier layer, the second barrier layer and/or one or more additional barrier layers can have several individual layer layers. Furthermore, the first barrier layer, the second barrier layer and/or one or more additional barrier layers can be designed as gradient layers.

The fluorine-doped silicon oxide layer and optionally the first barrier layer and/or the second barrier layer can be formed by atomic layer deposition.

According to various embodiments, the fluorine-doped silicon oxide layer and optionally the first barrier layer and/or the second barrier layer may be formed using reactive magnetron sputtering.

According to various embodiments, the fluorine-doped silicon oxide layer and the first barrier layer and/or the second barrier layer may be formed using the same magnetron.

According to various exemplary embodiments, the layer structure can be annealed after the layer has been deposited.

The reactive magnetron sputtering of the fluorine-doped silicon oxide layer may include sputtering a silicon target with oxygen while supplying a fluorine-containing gas, optionally forming the layer structure on a carrier and exposing the carrier to a high-frequency electromagnetic field.

The reactive magnetron sputtering can be monitored by means of an optical detector and the inflow of oxygen, the inflow of fluorine-containing gas and/or an operating voltage of the magnetron can be controlled by means of a signal from the optical detector.

According to various exemplary embodiments, the magnetron can be operated using a unipolar pulsed direct voltage or a bipolar pulsed direct voltage.

According to various exemplary embodiments, a layer structure may have a first fluorine-free barrier layer and a fluorine-doped silicon oxide layer on the first barrier layer, wherein the first barrier layer is designed to reduce the out-diffusion of fluorine from the fluorine-doped silicon oxide layer.

Furthermore, a second fluorine-free barrier layer can be provided on the fluorine-doped silicon oxide layer, the second barrier layer being designed to reduce the out-diffusion of fluorine from the fluorine-doped silicon oxide layer.

The layer structure may further have one or more additional fluorine-doped silicon oxide layers and/or one or more additional barrier layers on the layer structure, wherein fluorine-doped silicon oxide layers and barrier layers are formed alternately on top of one another.

The first barrier layer and/or the second barrier layer may include or consist of one or more of the following materials: silicon oxide, silicon nitride, aluminum oxide, silicon oxynitride, carbon, diamond-like carbon (DLC), and/or silicon carbide. The materials may be present as pure materials or compounds or as doped materials or doped compounds.

According to various embodiments, the first barrier layer and/or the second barrier layer may have multiple layers.

According to various exemplary embodiments, an acoustic wave component with a temperature compensation layer is provided. The temperature compensation layer can have a layer structure according to one of the above-mentioned exemplary embodiments or a layer structure can be formed according to one of the above-mentioned exemplary embodiments.

The acoustic wave component can be a SAW filter and/or a BAW filter.

The layer structure according to one of the above-mentioned exemplary embodiments can be used as a temperature compensation layer in an acoustic wave filter element. The acoustic wave component can be a SAW filter and/or a BAW filter.

Exemplary embodiments are shown in the figures and are explained in more detail below.

• 1A bis 1D den Ablauf eines Verfahrens zum Herstellen einer Schichtstruktur;
• 2A bis 2C verschiedene Konfigurationen von Schichtstrukturen;
• 3A und 3B jeweils eine Schichtstruktur in einem SAW-Filter;
• 4A bis 4C verschiedene Beispiele für BAW-Filter;
• 5 eine Abscheidevorrichtung für eine Schichtstruktur.

Show it

• 1A until 1D the sequence of a process for producing a layer structure;
• 2A until 2C various configurations of layered structures;
• 3A and 3B each a layer structure in a SAW filter;
• 4A until 4C various examples of BAW filters;
• 5 a deposition device for a layer structure.

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown, by way of illustration, specific embodiments in which the invention may be practiced. In this regard, directional terminology such as "top", "bottom", "front", "back", "front", "back", etc. is used with reference to the orientation of the figure(s) being described. Because components of embodiments may be positioned in a number of different orientations, directional terminology is for illustrative purposes and is not in any way limiting. It is to be understood that other embodiments may be used and structural or logical changes may be made without departing from the scope of the present invention. It is to be understood that the features of the various exemplary embodiments described herein may be combined with one another unless specifically stated otherwise. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

In the context of this description, the terms “connected”, “connected” and “coupled” are used to describe both a direct and an indirect connection, a direct or indirect connection and a direct or indirect coupling. In the figures, identical or similar elements are given identical reference numerals where appropriate.

In general, the layer structures described in the examples and the figures are suitable for integration into components/devices in which temperature compensation plays a role. Examples are sensors, filters, actuators, but also holders, housings or parts of housings and also structures between two components/devices, for example an intermediate layer between a chip and a heat sink structure. The following will be at For example, an acoustic wave filter (AW filter) is used as a non-exclusive example. An AW filter can be, for example, a surface acoustic wave filter (SAW filter, English surface acoustic wave filter) or an acoustic substrate wave filter (BAW filter, English bulk acoustic wave filter).

In the following, the term “barrier layer” is used as a synonym for a fluorine-free barrier layer.

1A shows schematically the sequence of a method 100 for producing a layer structure.

The method 100 may include, in 101, forming a first fluorine-free barrier layer. The method may include, in 103, forming a fluorine-doped silicon oxide layer on the first barrier layer. Further, in 105, the method may optionally include forming a second fluorine-free barrier layer on the fluorine-doped silicon oxide layer.

However, in various embodiments, only one fluorine-free barrier layer can be provided and a fluorine-doped silicon oxide layer can be formed on the fluorine-free barrier layer. The fluorine-free barrier layer is designed to reduce the out-diffusion of fluorine from the fluorine-doped silicon oxide layer (which in turn may be coupled to another layer, for example a substrate or another layer or layer structure).

In the 1B until 1D the method 100 is illustrated illustrated.

In 1B a first barrier layer 110 is formed, for example on a carrier. In 1C a fluorine-doped silicon oxide layer 120 is formed on the first barrier layer 110. The fluorine-doped silicon oxide layer 120 can be in direct physical contact with the first barrier layer 110 or the fluorine-doped silicon oxide layer 120 can be formed indirectly on the first barrier layer 110, for example with one or more intermediate layers between the first barrier layer 110 and the fluorine layer. doped silicon oxide layer 120. In 1D A second barrier layer 130 can be formed on the fluorine-doped silicon oxide layer 120. The fluorine-doped silicon oxide layer 120 can be in direct physical contact with the second barrier layer 130 or the second barrier layer 130 can be formed indirectly on the fluorine-doped silicon oxide layer 120, for example with one or more intermediate layers between the second barrier layer 130 and the fluorine layer. doped silicon oxide layer 120.

The first barrier layer 110 and/or the second barrier layer 130 can, for example, have or consist of silicon oxide, silicon nitride and/or aluminum oxide, silicon oxynitride, carbon, diamond-like carbon (DLC), and/or silicon carbide as a material. The materials may be present as pure materials or compounds or as doped materials or doped compounds. In various examples, the material may be formed according to different stoichiometric ratios. For example, the material can be present as SiO ₂ , Si ₃ N ₄ and/or Al ₂ O ₃ . There may also be other stoichiometric ratios of the material. Furthermore, the first barrier layer 110 and/or the second barrier layer 130 can be, for example, solid or porous. For example, a porous barrier layer can also serve as a low-k dielectric, that is, a barrier layer can fulfill other functions beyond reducing the out-diffusion of fluorine, for example in a component. Provision can be made to set a desired porosity of a layer using a magnetron.

In order to achieve a desired barrier effect of the first barrier layer 110 and/or the second barrier layer 130, the respective layer can be or will be grown at least as a closed monolayer of the layer material.

The first barrier layer 110 and/or the second barrier layer 130 can each also have several sublayers, for example a sublayer structure. For example, the first barrier layer 110 and/or the second barrier layer 130 may each have 1 to 5 layers. The sublayers can each have, for example, or consist of silicon oxide, silicon nitride, aluminum oxide and/or mixtures such as silicon oxynitride. Furthermore, the first barrier layer 110 and/or the second barrier layer 130 may include or consist of silicon oxynitride, carbon, diamond-like carbon (DLC), and/or silicon carbide. The materials may be present as pure materials or compounds or as doped materials or doped compounds. For example, one or more sublayers can serve primarily as a barrier to the out-diffusion of fluorine, while other sublayers take on the function of an adhesion-promoting layer or a support for adhesion promotion. Also, for example, a stack of mixed sublayers, for example alternating sublayers of different material, can both reduce the out-diffusion of fluorine and, for example, take on an optical function, for example as a Bragg mirror.

For example, depending on the material, different sublayers may be more suitable to form on a support or to form layers thereon, such as the fluorine-doped silicon oxide layer 120. For example, an underlayer structure can be designed so that crystal lattice coefficients to adjacent layers/supports or other adhesion parameters, for example in the case of amorphous materials, are/are adapted, so that, for example, the (later) detachment of layers can be avoided. The first barrier layer 110 and/or the second barrier layer 130 can be set up as homogeneous or inhomogeneous gradient layers.

The first barrier layer 110 and/or the second barrier layer 130 or one or more, for example all, sublayers of the first barrier layer 110 and/or the second barrier layer 130 can each be used, for example, by means of atomic layer deposition (ALD), vapor phase deposition (CVD - for example PECVD), Ion beam sputtering deposition (IBSD), high-performance pulsed magnetron sputtering (HiPIMS) and/or reactive magnetron sputtering. Sublayers of a barrier layer can each be formed using different methods.

For example, a barrier layer and its one or more sublayers can be formed using a deposition process. For example, in (reactive) magnetron sputtering, the gas inflows can be time-controlled in such a way that different sublayers lying one on top of the other can be realized in a deposition system and with a magnetron target, for example comprising silicon. When forming the first and/or second barrier layers 110 and 130 or at least a sublayer of the respective barrier layer using magnetron sputtering, the fluorine-doped silicon oxide layer 120 can be formed using the same magnetron and, for example, with the same magnetron target.

After the magnetron sputtering of one, some or all layers or sublayers of the layer structure, the layer structure can be annealed. It can also be tempered several times, for example for different layers or sublayers. By means of annealing, for example, the adhesion of one or more layers or sublayers of the layer structure to one another or to a support can be improved. The annealing can also be designed to influence the crystal structure (or amorphous structure), composition, density and/or the porosity of one or more layers or sub-layers of the layered structure. The annealing can also serve to incorporate the fluorine in the fluorine-doped silicon oxide layer 120 into and/or between the crystal structure (or amorphous structure) and/or to homogenize the concentration of fluorine in the silicon oxide layer 120.

The fluorine-doped silicon oxide layer 120 may be in various stoichiometric ratios according to various examples. The fluorine-doped silicon oxide layer 120 may, for example, have a thickness of 10 nm to 100 μm or greater. In various examples, the fluorine-doped silicon oxide layer 120 may have a thickness of 0.5 μm to 10 μm, for example 1 μm to 5 μm, for example 1 μm to 2 μm. The thickness of the fluorine-doped silicon oxide layer 120 can be adjusted depending on the desired temperature compensation and/or based on other functionalities of the layer, for example electrical or thermal insulation, layer stability, distance from other components.

The fluorine concentration in the first barrier layer and/or the second barrier layer can be in a range of approximately 1% by weight to 5% by weight, or also in a range of approximately 10% by weight to 12% by weight (measured with EDX , for example for bipolar sputtering) or in a range of approximately 18% by weight to 22% by weight (for example 20% by weight) (measured with EDX, for example for unipolar sputtering).

The fluorine-doped silicon oxide layer 120 can be formed using reactive magnetron sputtering. For example, this can include sputtering a silicon target with an oxygen-containing gas while supplying a fluorine-containing gas. Oxygen can be admitted in an amount, for example into a reactor chamber, so that a desired/required target voltage is established on the silicon target. For example, pure oxygen or oxygen-containing gases such as N ₂ O can be used. In addition, a fluorine-containing gas (as a precursor) can be admitted, for example F ₂ (pure or diluted), NF ₃ , CF ₄ , SF ₆ , CHF ₃ , which supplies fluorine for the doping. A carrier, for example a holder on which the fluorine-doped silicon oxide layer 120 is applied, can be exposed to a high-frequency electromagnetic field (for example with a frequency of 13.56 MHz) in order to support the formation of the fluorine-doped silicon oxide layer 120. For example, ions of the magnetron's plasma can be accelerated onto a carrier using a field. For example, this can shorten the process time, the crystal structure/amorphous structure of the fluorine-doped silicon oxide layer 120 formed, layer topology and structure coverage and the fluorine concentration in the fluorine-doped silicon oxide layer 120 can be influenced.

Reactive magnetron sputtering can be monitored, for example, using an optical detector. This means that the inflow of oxygen or an oxygen precursor, the inflow of fluorine-containing gas and/or an operating voltage of the magnetron can be controlled by means of a signal from the optical detector. A signal can generally be understood here as information transmission/communication.

An optical detector can be, for example, a spectrometer, whereby the optical detector cannot be designed or not only for the visible wavelength range, but also, for example, for an ultraviolet and/or an infrared spectral range. For example, the flow (amount/rate) of the fluorine-containing gas can be monitored using one or more spectral lines typical of fluorine in the magnetron's plasma. Depending on the intensity (absolute or relative) of the measured spectral line/lines/spectral bands, the amount of fluorine that can then be available for doping can be determined and controlled.

For example, the magnetron can be operated using a unipolar or a bipolar pulsed direct voltage. A bipolar pulsed direct voltage showed better fluorine stability in preliminary tests.

Fluorine stability can be examined using Fourier-transformed infrared spectroscopy (FTIR) for the formation of ω ₄ bonds. The term “ω ₄ bonds” clearly refers to Si-O bonds whose stretching vibration is typically 1075 cm ^-1 (or also 1065 cm ^-1 ) in the IR spectrum. This peak that can be measured there is referred to as the ω ₄ peak of the SiO ₂ spectrum. The shift of this peak roughly correlates with the content of bound fluorine. This type of bonding can be correlated with the refractive index of the fluorine-doped silicon oxide in the silicon oxide layer 120. Depending on the process parameters, the formation of the ω ₄ bond can be influenced. Typical positions of this bond range from 1050 cm ^-1 to 1100 cm ^-1 , from which the concentration of fluorine in the silicon oxide can be at least approximately determined.

A study of fluorine stability can provide parameters for regulating/controlling a deposition process.

The refractive index of silicon oxide drops from approximately 1.48 (pure silicon oxide) to 1.41 (fluorine-doped silicon dioxide). One or more optical sensors can also monitor the refractive index of one or more layers/sublayers of a layer structure during a deposition process and, for example, supply data to a control system for a deposition system.

The fluorine-doped silicon oxide layer 120 can also be annealed, for example together with one or more barrier layers and sublayers of barrier layers. For example, annealing can support the incorporation of fluorine into the silicon oxide. Preliminary studies have so far shown a dependence of the ω4 bond before and after heating. Annealing can also take place in the magnetron separation system itself.

The first barrier layer 110 and the second barrier layer 130 or generally barrier layers in different layer structures can be arranged in such a way that they shield one or more fluorine-doped silicon oxide layers 120 from a carrier, metal lines and / or other layers or components or from diffusing fluorine protect. For example, it can be prevented or delayed that the concentration of fluorine in one or more fluorine-doped silicon oxide layers 120 decreases and thus the temperature compensation property decreases. In addition, other components, such as metal lines or electrical contacts, can be protected from corrosion caused by diffused fluorine.

The following 2A until 2C show different configurations of a layer structure. The individual layers/sublayers of these layer structures can be formed according to the method 100.

2A shows schematically a layer structure 200 with three barrier layers 201 and two fluorine-doped silicon oxide layers 203. 2 B shows schematically a layer structure 210 with four barrier layers 211 and three fluorine-doped silicon oxide layers 213.

A layer structure or the formation thereof may include one or more fluorine-doped silicon oxide layers 203 and 213 and/or one or more barrier layers 201 and 211. The plurality of fluorine-doped silicon oxide layers 203 and 213 and the plurality of barrier layers 201 and 211 may be formed alternately on top of each other. As in 2A and 2 B shown, the layers can be arranged such that a fluorine-doped silicon oxide layer 203 or 213 is arranged/formed between two barrier layers 201 and 211. The number of fluorine-doped silicon oxide layers 203 and 213 and barrier layers 201 and 211 are not limited and depend on the desired application.

2C shows schematically a layer structure 220 with four barrier layers 221 and four fluorine-doped silicon oxide layers 223 and 225. In contrast to the layer structures 200, 210 and 223, the fluorine-doped silicon oxide layer 225 is not surrounded by a barrier layer 221 on both sides. For example, the layer structure can be arranged on or formed on a support that also has the property of preventing fluorine from diffusing out of the fluorine-doped silicon oxide layer 225, so that a barrier layer may not be necessary here. The same can apply to the topmost of the four fluorine-doped silicon oxide layers 223 in the sense of the figure.

In the 2A until 2C Several fluorine-doped silicon oxide layers and barrier layer are each marked with a reference number for the purpose of overview. However, the different layers can each have or consist of different materials and/or have different sublayer structures/layer structures and/or have different thicknesses. For example, the fluorine-doped silicon oxide layers can have the same or different fluorine concentrations.

In general, the number of fluorine-doped silicon oxide layers and barrier layer can be increased, for example as in 2A until 2C shown to achieve improved temperature compensation. For example, fluorine is extracted from the middle fluorine-doped silicon oxide layer 213 2C prevented from diffusing by several barrier layers. An optical refractive index can also be adjusted with several layers. Furthermore, for example in a fault-tolerant manufacturing process, it can be ensured that at least one or more of a plurality of fluorine-doped silicon oxide layers has a suitable temperature compensation property. Since the number of layers can be variable, as described above, a layer structure can also be tailored to the requirements of a component. For example, a layered structure for a SAW and/or BAW filter with multiple layers may be more suitable for transmitting acoustic waves. For example, the mechanical stability, the possible detachment of layers and/or thermal conductivity of a layer structure can also be controlled in this way.

3A shows schematically a layer structure 305 in a SAW filter 300.

To illustrate this, the use of a layer structure in a SAW filter 300 in 3A and 3B and in a BAW filter in 4A , 4B and 4C shown. These can, for example, be integrated in a chip structure, for example monolithically integrated in a silicon carrier. However, the layer structure can also be used in other systems, components and devices, for example for temperature compensation.

The layer structure 305 can, for example, according to a method 1A until 1D be manufactured and/or in accordance with 2A until 2C be constructed.

The SAW filter 300 has a carrier 301 and electrical metal lines 303 arranged on the carrier. The layer structure 305 is arranged above the electrical metal lines 303 and an optional cover layer 307 is arranged above the layer structure 305.

The carrier 301 can be, for example, a piezoelectrically active carrier, for example a piezoelectric single crystal. The carrier can, for example, have or consist of lithium niobate and/or quartz.

The metal lines 303 can, for example, be designed as electrodes that interlock in a comb shape. For example, an alternating voltage, for example a high-frequency voltage, can be applied to the metal lines 303. Due to the piezo effect and the electric field created on the metal lines 303, the carrier 301 is distorted near the surface of the carrier 301. This distortion leads to acoustic waves on the surface of the carrier 301. Depending on the material and the structure of the metal lines 303, the acoustic waves can be transmitted with a corresponding amplitude so that a filter element can be realized. The metal lines 303 can, for example, be applied photolithographically to the surface of the carrier 301.

The layer structure 305 can, for example, be formed or arranged conformally, or approximately following the surface, on the surface of the carrier 301 and the metal lines 303. For example, the layer structure 305 may be formed/arranged in physical contact with the surface of the carrier 301 and the metal lines 303.

In other examples, one or more intermediate layers, for example a protective layer and/or an adhesion-promoting layer, may be between the layer structure 305 and the Surface of the carrier 301 and the metal lines 303 are formed/arranged. For example, one or more intermediate layers can be formed/arranged in such a way that gaps between metal lines 303 are filled so that the layer structure 305 runs essentially flat, for example with a surface parallel to the surface of the carrier 301. In various examples, the surface of the carrier 301 is not flat and/or in various examples further metal lines and other objects can also be applied to the surface of the carrier 301. The layer structure 305 can also be applied in a conformal manner or can be flat, for example by means of an intermediate layer.

The exact shape of the layer structure 305 or conformity with surfaces lying beneath the layer structure or, in other examples, a layer thickness variation of one or more layers and/or sub-layers of the layer structure 305 can be realized depending on the desired component, for example on the acoustic properties of a SAW or BAW -Filter can be adjusted.

The layer structure 305 may completely cover a surface of the carrier 301 or completely cover only structures such as the metal lines 303 and leave parts of the carrier 301 exposed. The metal lines 303 can also only be partially covered by the layer structure 305 in various examples. The geometric shape of the layer structure 305 can be adapted to the desired functionality of the SAW filter 300.

In various examples, the layer structure 305 can be applied directly to the carrier 301 and to the metal lines 303 or to an intermediate layer, for example deposited directly there. In other examples, the layer structure 305 can be formed, for example deposited, on an auxiliary carrier and the layer structure 305 can be transferred from the auxiliary carrier 305 to the carrier 301 and to the metal lines 303 or to an intermediate layer.

The cover layer 307 is optional and can serve to protect the SAW filter or the layer structure 305. The cover layer 307 can, for example, be formed using similar methods, for example using the same equipment for producing (at least parts of) the layer structure 305. In addition to or instead of the cover layer 307, the SAW filter 300 can be encapsulated using encapsulation.

3B shows schematically a layer structure 325 in another SAW filter 320.

The SAW filter 320 has a similar structure to the SAW filter 300 with the difference that the layer structure 325 is arranged under a carrier 321. Statements regarding the SAW filter 300 or its production are equally valid here, for example the carrier 321 can also have a piezoelectrically active material.

The SAW filter 300, like the SAW filter 300, has a carrier 321 and metal lines 323 on the carrier 321. The carrier 321 is applied to a layer structure 325. Optionally, the layer structure 325 is applied to a second carrier 327.

The layer structure 325 can, similar to the SAW filter 300, be in physical contact with the carrier 321 and/or the second carrier 327. In various examples, an intermediate layer, for example a protective layer and/or an adhesion-promoting layer, can be applied/formed between the layer structure 325 and between the carrier 321 and/or between the second carrier 327.

Optionally, the SAW filter 320 can be protected with a cover layer and/or an encapsulation.

4A until 4C show various examples of BAW filters.

4A shows schematically an example of a BAW filter 400.

In general, the way a BAW filter works is comparable to the way a SAW filter works, with the difference that instead of using surface waves, acoustic waves in the material are (also) used. Statements regarding a SAW filter can also apply to the BAW filter 400; for example, the carrier can also have a piezoelectrically active material here.

The BAW filter has a carrier 401 and metal lines 403, which can be applied to different sides of the carrier 401. For example, as shown in the figure, on opposite sides of the carrier 401. The metal lines 401 on different sides of the carrier 401 are marked with the same reference numeral for clarity, but may differ from one another.

4B shows schematically a BAW filter 430 based on the BAW filter 400 with different possible positions of a layer structure 431.

In various examples, the layer structure can be according to the examples described above, for example in the context of the figures 1A until 1 .D and 2A until 2C be arranged and formed. Furthermore, the BAW filter 430 can have one or more layer structures, for example at the possible positions 431.

As already in the context of 3A described for the SAW filter 300, a layer structure can be arranged/formed on the metal lines 401 and the surface of the carrier 431, in the sense of the figure below and/or above the carrier 403. Further possible positions 431 are within the carrier 403, or the carrier can consist of two halves and/or between a metal line (bottom/top) 401 and the carrier 403.

In these examples too, a layer structure can be embedded using intermediate layers. This means that one or more layer structures at the possible positions 431 can be arranged above and/or below on an intermediate layer in the sense of the figure.

In addition, if several layer structures are formed/arranged, the layer structures can, for example, as in the context of 1A until 1D described, differentiate from each other.

4C shows schematically another BAW filter 460 based on the BAW filter 400 with different possible positions of a layer structure 465.

In 4C is the BAW filter 400 according to 4A applied to an auxiliary carrier 461 and optionally on a further auxiliary carrier 463. In various examples, the BAW filter 430 may also be in accordance with 4B related/formed.

The auxiliary carrier 461 and/or the further auxiliary carrier 463 can serve, for example, as a resonator and can, for example, have sound-reflecting layers.

The layer structure can, for example, according to 1A until 1 .D and 2A until 2C be/are formed and can be arranged/formed, for example, in the auxiliary carrier 461 and/or the further auxiliary carrier 463 and/or at the boundary of the auxiliary carriers 461 and 463. Here too, the layer structure can be realized using intermediate layers, as described above.

5 shows schematically a deposition device 500 for a layer structure.

In this example, the deposition device 500 is set up as a PVD system (Physical Vapor Deposition), in particular as a magnetron deposition device. The deposition device 500 can be set up to have a layer structure according to the previously mentioned examples, for example in the context of 1A until 4C described to form.

The separation device 500 can have a chamber 501. The chamber 501 can be cooled and/or heated by means of a temperature control device 503, for example controlled by a controller 515. The temperature control device 503 can also be used to cool and/or heat individual parts in the chamber 501, for example a carrier/holder 509. After the deposition of a layer structure, layer of a layer structure and/or sublayer of a layer of a layer structure, the layer structure can be tempered in the deposition device 500, for example by means of the tempering device 503.

A magnetron 505 can be arranged in the chamber 501. The magnetron 505 can be operated using a power supply 513. The energy supply 513 and/or the magnetron 505 can be controlled directly with a controller 515. The magnetron 505 can deposit material 507 onto a carrier 508 during operation. For example, the magnetron can be operated with a unipolar or a bipolar pulsed direct voltage by means of the energy supply 513. Depending on the voltage and voltage modulation, the deposition of a layer structure can be controlled and, for example, parameters such as porosity, density, thickness and dopant concentration of the layer structure, or the individual layers of the layer structure, as well as deposition time and general tolerances during a deposition can be controlled and adjusted. The magnetron 505 can be used in particular to deposit two or more, for example all, layers of a layer structure. This means that multiple systems for depositing a layer structure may be unnecessary or the number of systems required can be reduced.

As shown in the figure, the magnetron can be arranged above/upside down on the carrier 508. However, other positions/relative positions can also be provided in a separation device 500.

As explained above, the carrier 508 can, in various examples, be a carrier, an auxiliary carrier, or a (possibly not yet fully manufactured) component such as a SAW and/or a BAW filter. The chamber 501 can have a lock to insert or remove the carrier 508. to carry out. The carrier 508 can be placed on a carrier/holder 509 or held with it. The carrier/holder 509 can be brought into a favorable deposition position relative to the magnetron 505 by means of motors, for example controlled by the controller 515. In other examples, the position of the magnetron 505 or the position of the magnetron 505 and the position of the carrier 508 may be changed.

The carrier/holder 509 can be cooled and/or heated using the temperature control device 503, for example controlled by the controller 515. The controller 515 can also be set up to supply the carrier/mount 509 with energy. The energy can be used, for example, for sensors/measuring instruments, such as a layer thickness sensor, or holding devices, for example clamps, in/on the carrier/holder 509. The energy can be used, for example, to operate an electrode 511. The electrode 511 can be arranged in the carrier/holder 509, for example on the surface, so that the carrier 508 rests on the electrode 511. For example, a voltage, for example a high-frequency voltage (for example 13.56 MHz), can be applied to the electrode 511. This voltage can influence the deposition, for example the parameters mentioned above, or the deposition can be controlled and/or regulated by means of the voltage.

The chamber 501 may have one or more gas supply elements 519. One or more process gases from one or more gas reservoirs 521, 523 can be admitted into the chamber via one or more gas supply elements 519, for example controlled by the controller 515. For example, oxygen (and/or an oxygen-containing gas) and a fluorine-containing gas can be admitted for the deposition of the layer structure. Furthermore, other gases, for example nitrogen or a noble gas such as neon or argon, can also be admitted. These other gases can be used, for example, to moderate the deposition process, to adjust an atmosphere in the chamber, for example a pressure, and/or to purge the chamber. For example, nitrogen or a gas containing nitrogen can be used for the deposition of silicon nitride. This means that the separation device can separate different materials, for example one after the other, depending on the gases supplied. In various examples, at least some of a plurality of gas supply elements 519 are provided with conduits so that one or more gases near the magnetron 505 can be admitted into the chamber 501. In various examples, the magnetron 505 itself may have gas lines and the gas supply elements 519 may be connected to them.

The chamber 501 can have at least one optical detector 517 or have an interface, for example a viewing window, for at least one optical detector 517. One or more optical detectors 517 can be used to monitor the deposition of the layer structure, for example the thickness of individual layers of the layer structure, and/or to monitor the plasma that occurs at the magnetron 505. The one or more optical detectors 517 may be controlled by the controller 515 and/or provide parameters/signals to the controller 515 for controlling/monitoring other parts of the separation device 500.

For example, reactive magnetron sputtering can be monitored using the optical detector 517 and the inflow of oxygen, the inflow of fluorine-containing gas and/or an operating voltage of the magnetron can be controlled using a signal from the optical detector 517. For example, one or more optical detectors 517 can be used as a spectrometer. The plasma that forms in the magnetron 505 can be monitored using a spectrometer. For example, the concentration and/or the amount of fluorine and oxygen (for example also the ratio of fluorine to oxygen) in the plasma can be determined based on the intensity of spectral lines.

The pump system 525 can be set up, for example controlled by the controller 515, to evacuate the chamber 501 up to a process pressure. A process pressure can be, for example, a (technical) vacuum/high vacuum. The pump system 525 can have one or more pumps, for example a multi-stage pump system, for example with one or more rough vacuum pumps and one or more high vacuum pumps, for example a turbomolecular pump.

The controller 515 can be implemented as one or more controllers, for example realized by means of one or more microcontrollers and/or computers/processors. For example, the control can be a central control or include several controls. If there are multiple controllers, they can be independent/not connected or coupled. For example, if there are several controllers, one controller can coordinate the other controllers.

Claims (21)

Method for producing a layer structure, comprising: • Forming a first fluorine-free barrier layer, • Forming a fluorine-doped silicon oxide layer on the first barrier layer, the first barrier layer being designed to reduce the out-diffusion of fluorine from the fluorine-doped silicon oxide layer. Procedure according to Claim 1 , further comprising: forming a second fluorine-free barrier layer on the fluorine-doped silicon oxide layer, the second barrier layer being designed to reduce the out-diffusion of fluorine from the fluorine-doped silicon oxide layer. Procedure according to Claim 1 or 2 , further comprising: forming one or more additional fluorine-doped silicon oxide layers and/or one or more additional barrier layers on the layer structure, wherein fluorine-doped silicon oxide layers and barrier layers are alternately formed on top of one another. Procedure according to one of the Claims 1 until 3 , wherein the first barrier layer, the second barrier layer and/or one or more additional barrier layers comprise or consist of one or more of the following materials, doped or undoped: • silicon oxide; • Silicon nitride; • Aluminum oxide; • Silicon oxynitride; • Carbon; • diamond-like carbon; and/or • silicon carbide. Procedure according to one of the Claims 1 until 4 , wherein the first barrier layer, the second barrier layer and / or one or more additional barrier layers have multiple layers. Procedure according to one of the Claims 1 until 5 , wherein the fluorine-doped silicon oxide layer and optionally the first barrier layer are formed by atomic layer deposition. Procedure according to one of the Claims 2 until 6 , wherein the fluorine-doped silicon oxide layer and optionally the second barrier layer are formed by atomic layer deposition. Procedure according to one of the Claims 1 until 5 , wherein the fluorine-doped silicon oxide layer and optionally the first barrier layer are formed using reactive magnetron sputtering. Procedure according to one of the Claims 2 until 5 or 8th , wherein the fluorine-doped silicon oxide layer and optionally the second barrier layer are formed using reactive magnetron sputtering. Procedure according to Claim 8 or 9 , wherein the fluorine-doped silicon oxide layer and the first barrier layer and/or the second barrier layer are formed using the same magnetron. Procedure according to one of the Claims 8 until 10 , whereby the layer structure is annealed after the first fluorine-free barrier layer has been formed. Procedure according to one of the Claims 8 until 11 , wherein the reactive magnetron sputtering of the fluorine-doped silicon oxide layer comprises sputtering a silicon target with oxygen while supplying a fluorine-containing gas, optionally forming the layer structure on a carrier and exposing the carrier to a high-frequency electromagnetic field. Procedure according to Claim 12 , wherein the reactive magnetron sputtering is monitored by means of an optical detector and the inflow of oxygen, the inflow of fluorine-containing gas and / or an operating voltage of the magnetron are controlled by means of a signal from the optical detector. Procedure according to one of the Claims 8 until 13 , whereby the magnetron is operated by means of a unipolar pulsed direct voltage or a bipolar pulsed direct voltage. Layer structure, comprising: • a first fluorine-free barrier layer, • a fluorine-doped silicon oxide layer on the first barrier layer, and • wherein the first barrier layer is designed to reduce the out-diffusion of fluorine from the fluorine-doped silicon oxide layer. Layer structure according to Claim 15 , further comprising: a second fluorine-free barrier layer on the fluorine-doped silicon oxide layer, wherein the first barrier layer and the second barrier layer reduce the out-diffusion of fluorine from the fluorine-doped silicon oxide layer. Layer structure according to Claim 15 or 16 , further comprising: one or more additional fluorine-doped silicon oxide layers and / or one or more additional barrier layers on the layer structure, with fluorine-doped silicon oxide layers and barrier layers being formed alternately on top of one another. Layer structure according to one of Claims 15 until 17 , wherein the first barrier layer and/or the second barrier layer comprise or consist of one or more of the following materials, doped or undoped: • silicon oxide; • Silicon nitride; • Aluminum oxide; • Silicon oxynitride; • Carbon; • diamond-like carbon; and/or • silicon carbide. Layer structure according to one of Claims 15 until 18 , wherein the first barrier layer and/or the second barrier layer have multiple layers. Acoustic wave component with a temperature compensation layer, wherein the temperature compensation layer has a layer structure according to one of Claims 15 until 19 has, optionally the acoustic wave component being a SAW filter or a BAW filter. Using a layer structure according to one of Claims 15 until 19 as a temperature compensation layer in an acoustic wave filter element, optionally the acoustic wave component being a SAW filter or a BAW filter.

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