Method of modifying stress in the nitride film, method of modifying stress in aluminum nitride film and an apparatus for film layer stress control

Abstract

The embodiments described herein relate to methods for altering stress in a nitride film, methods for altering stress in an aluminum nitride film, and apparatus for film stress control. In some embodiments, a nitride film can be formed on a substrate, a metrological scan of the nitride film can be performed to measure stress information of the nitride film at multiple locations, and ions can be directed to the nitride film during ion implantation. The ion implantation dose can be varied across the entire nitride film based on stress information at each of the multiple locations.

Description

Localized Membrane Stress Regulation by Implantation This disclosure relates to stress control in a membrane layer, and more particularly, to localized stress modulation by ion implantation of an aluminum nitride membrane. Devices such as integrated circuits, memory devices, and logic devices can be fabricated on a substrate such as a silicon wafer by a combination of deposition processes, etching, ion implantation, annealing, and other processes. The use of piezoelectric materials in microelectromechanical systems (MEMS) is a well-known way to generate electromechanical effects. Doped and undoped aluminum nitride (AlN) is a class of materials commonly used because it can produce a desired piezoelectric effect. Although AlN is a common material, AlN can generate an in-wafer (WiW) stress range of 60 megapascals to 500 megapascals due to its columnar structure, which can impede the performance of certain MEMS systems such as bulk acoustic wave (BAW) filters. Embodiments of this disclosure are provided in view of these and other considerations. This summary is provided to introduce a series of concepts that will be further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter. In one embodiment, a method can include: forming a nitride membrane over a substrate; performing a metrology scan of the nitride membrane to measure stress information of the nitride membrane at a plurality of locations; and directing ions to the nitride membrane during ion implantation, wherein the dose of the ion implantation varies across the nitride membrane based on the stress information of the nitride membrane at each of the plurality of locations. In another embodiment, a method of changing stress in an aluminum nitride membrane can include: forming the aluminum nitride membrane over a substrate; performing a metrology scan of the nitride membrane to measure stress information of the aluminum nitride membrane at a plurality of locations; and directing ions to the aluminum nitride membrane during ion implantation, wherein the dose of the ion implantation varies across the aluminum nitride membrane based on the stress information of the aluminum nitride membrane at each of the plurality of locations. In another embodiment, an apparatus for controlling stress in a film layer may include: a beam scanner operable to scan an ion beam relative to a substrate; and a controller coupled to the beam scanner, the controller including a processor and a memory unit, the memory unit coupled to the processor and including a scanning routine that operates on the processor to perform a metrology scan of an aluminum nitride film formed on top of the substrate to determine stress information at each of a plurality of locations of the aluminum nitride film. The controller may further be operable to: generate a dose pattern based on the stress information determined for each of the plurality of locations of the aluminum nitride film; and direct ions to the aluminum nitride film during ion implantation, wherein the dose of the ion implantation varies across the aluminum nitride film based on the dose pattern. Embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some embodiments are shown. The subject matter of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subject matter to those skilled in the art. In the drawings, like numerals refer to like elements throughout. The embodiments described herein relate to techniques and apparatus / systems for improving stress control in a film layer, such as an aluminum nitride (AlN) film layer deposited on a silicon wafer. As described above, reducing the WiW stress range will help improve the performance of a BAW filter. Prior art solutions for reducing stress within a wafer include changing the film deposition recipe. This approach may be successful when the WiW stress range is 100 megapascals or less. However, embodiments of the present disclosure may flatten the stress profile range for stress ranges greater than 100 megapascals, which is beneficial for improving device quality and yield. In the present disclosure, by applying localized implantation of, for example, He+, B+, or N+ into an aluminum nitride film layer, where the aluminum nitride film may be approximately 1 micron, the localized stress induced by the film layer can be modulated from tensile to compressive. In some non-limiting examples, a medium current implantation tool may be used to change such a thick film with appropriate energy and dose sufficient to achieve the desired stress change. Generally, as the dose increases, the stress decreases. In the case of using a metrology tool and a controller for generating a localized dose pattern across a wafer, the in-wafer stress may be reduced due to the more uniform stress generated by the variable dose implantation across the wafer. Referring now to FIG. 1, a portion of the device 100 according to an embodiment of the present disclosure will be discussed. Although non-limiting, the device 100 may represent a portion of a microelectromechanical system (e.g., a bulk acoustic wave (BAW) filter) including a substrate 102 (e.g., silicon). Although not shown, the device may further include a seed layer / metal film stack. The device 100 may further include a nitride film 104 formed over the substrate 102 and the seed layer / metal film stack, such as a doped or undoped AlN film layer having a thickness approximately between 0.5 microns and 1.5 microns. The nitride film 104 may be directly deposited on top of the upper surface 106 of the substrate 102 using, for example, a physical vapor deposition (PVD) sputtering process. As used herein, the term "physical vapor deposition (PVD)" refers to various vacuum deposition methods. In PVD, physical processes such as sputtering and evaporation are used to generate a vapor of the coating material supplied from a target in atomic, molecular, or ionic form. They are then transported to the substrate 102 and deposited on the substrate 102 to form a coating. In some non-limiting PVD processes, the substrate temperature is substantially lower than the melting temperature of the target material, enabling the coating of temperature-sensitive materials. The PVD method may use vacuum deposition, in which the coating is deposited synchronously over the entire wafer surface. Although not shown, a cluster tool known as an Endura® system may be used to perform the PVD sputtering process for forming the nitride film 104, and the Endura® system may be purchased from Applied Materials, Inc. of Santa Clara, California. As shown in FIGS. 2A to 2B, a metrology scan 112 can then be performed along the nitride film 104 to measure the stress levels of the nitride film 104 at multiple locations 108A to 108N (FIG. 2B). In some embodiments, the metrology scan can be performed by a film stress measurement (FSM) metrology tool 120, which can be operated to measure stress across the entire diameter of the device 100 at multiple orientations (e.g., 5 to 10 orientations). The FSM metrology tool 120 can further be operated to map the multiple locations 108A to 108N that can be uniformly distributed across the entire nitride film 104 and associate stress information with each of the multiple locations 108A to 108N. When the distribution is consistent or uniform, the multiple locations 108A to 108N can be identified according to a grid or coordinate system. The stress information from the multiple locations 108A to 108N can be used to generate a dose pattern, which will be described in more detail below. According to an exemplary embodiment, the deposited nitride film 104 can have tensile stress in one or more regions. In other embodiments, the nitride film 104 can have neutral stress (zero stress) or compressive stress. In still other embodiments, the stress across the entire nitride film 104 can vary and can include any combination of neutral stress, tensile stress, and / or compressive stress. Although only a single layer is shown, there can be more than one nitride film layer in alternative embodiments. As shown in FIG. 3, ion implantation 125 (e.g., scanned spot or ribbon ion beam implantation) can then be performed to direct ions into the nitride film 104. In the example shown, the ions can be B+, N+ or He+ ions, which are directed into the upper surface 127 of the nitride film 104 to locally change the stress in the nitride film 104 at one or more of the plurality of locations 108A to 108N (FIG. 2B). In some embodiments, a dose pattern for ion implantation is generated based on the stress information determined for each of the plurality of locations 108A to 108N of the nitride film 104. For example, the dose pattern can vary proportionally with the stress information detected at each of the plurality of locations 108A to 108N. Generally, ion implantation 125 provides a higher dose of implantation in those regions with higher stress and a lower dose of implantation in those regions with relatively lower stress. In other words, the ions of ion implantation 125 can be implanted into the first location 108A of the plurality of locations at a first dose and into the second location 108N of the plurality of locations at a second dose, where the first dose is greater than the second dose, and where the first stress value of the nitride film 104 measured at the first location 108A is greater than the second stress value of the nitride film 104 measured at the second location 108N. In the graph 130 shown in FIG. 4, a non-limiting example of such a relationship is shown for a 200 mm wafer. Such a relationship shown can be applicable to different wafer sizes, such as 150 mm, 200 mm, 300 mm, etc. In the case of using a dose pattern for generating a controlled dose variation across the nitride film 104 during implantation, the stress within the wafer can be reduced to produce a more uniform stress across the entire device 100. The dose pattern can be more affected by the regional variations in film thickness and ion species. According to various embodiments, the ion energy of ion implantation 125 can be tuned to implant ions within an appropriate depth of the nitride film 104, thereby inducing a sufficient change in the stress state. In some examples, a medium current implantation tool can be used to direct ions into the nitride film 104 at an energy of approximately 200 keV to 300 keV and at a dose within the range of 1E13 to 1E15. In other words, the dose ratio between the minimum dose value and the maximum dose value of ion implantation 125 can be between 6 and 10, preferably 8. However, since the specific implantation energy and dose values can vary, the embodiments herein are not limited to such a context. FIG. 5A shows a schematic top view of an ion implantation system (or ion implanter 200) for stress control according to an embodiment of the present disclosure. The ion implanter 200 represents a process chamber that contains, among other components, an ion source 204 for generating an ion beam 208 and a series of beam line components. The ion source 204 may include a chamber for receiving a gas stream and generating ions. The ion source 204 may also include a power supply disposed adjacent to the chamber and an extraction electrode assembly (not shown). The beam line components may include, for example, an analyzer magnet 220, a mass resolving slit (MRS) 224, a steering / focusing component 226, and a terminal station 230 including a substrate holder 231 and a substrate 232. Although the ion implanter 200 described herein is a medium-current (MC) ion implanter, it should be understood that a high-current (HC) ion implanter may also be used in alternative embodiments. It should be further understood that the substrate 232 may be the same or similar to the substrate 102 described herein. The ion implanter 200 may further include a beam scanner 236 positioned along the beam line 238 between the MRS 224 and the terminal station 230. The beam scanner 236 may be arranged to receive the ion beam 208 as a point beam and scan the ion beam 208 along a fast scan direction (e.g., parallel to the X-axis in the Cartesian coordinate system shown). It should be noted that the substrate 232 may be scanned along the Y-axis, so that when the ion beam 208 is scanned back and forth synchronously along the X-axis, a given ion treatment may be applied to a given area of the substrate 232. The ion implanter 200 may have other components (such as a collimator (not shown for clarity) known in the art) to direct the ions of the ion beam 208 to the substrate 232 along a series of parallel trajectories after scanning. In various embodiments, the ion beam 208 may be scanned at a frequency of a few hertz, 10 hertz, 100 hertz, up to a few kilohertz, or greater than a few kilohertz. For example, the beam scanner 236 may use a magnetic scanning element or an electrostatic scanning element to scan the ion beam 208, as known in the art. By rapidly scanning the ion beam 208 back and forth (e.g., along the X-axis) above the fast scan direction, the ion beam 208 may deliver a target ion dose with a uniform density across the entire substrate 232. According to various embodiments, the ion beam 208 may be controlled in response to user input to generate a target implantation pattern by combining the scan of the substrate 232 with the scan of the ion beam 208. For example, the ion implanter 200 may further include a controller 240 coupled to the beam scanner 236 to coordinate the operations of the beam scanner 236 and the substrate holder 231. As further shown in FIG. 5A, the ion implanter 200 may include a user interface 242 also coupled to the controller 240. The user interface 242 may be implemented as a display and may include user selection devices, including a touch screen, display menus, buttons, knobs, and other devices known in the art. According to various embodiments, the user interface 242 may send instructions to the controller 240 to generate an appropriate implantation pattern for the substrate 232 and the film layer (not shown) formed thereon based on user input. As further shown in FIG. 5B, the controller 240 may include a processor 252, such as a microprocessor of a known type, a dedicated processor chip, a general-purpose processor chip, or a similar device. The controller 240 may further include a memory or memory unit 254 coupled to the processor 252, where the memory unit 254 contains a scanning routine 256. The scanning routine 256 may operate on the processor 252 to manage the scanning of the ion beam 208 and the substrate 232 as described below. The memory unit 254 may include a product. In one embodiment, the memory unit 254 may include any non-transitory computer-readable medium or machine-readable medium, such as optical storage, magnetic storage, or semiconductor storage. The storage medium may store various types of computer-executable instructions to implement one or more of the logical processes described herein. Examples of computer-readable storage media or machine-readable storage media may include any tangible medium capable of storing electronic data, including volatile memory or non-volatile memory, removable memory or non-removable memory, erasable memory or non-erasable memory, writable memory or rewritable memory, and the like. Examples of computer-executable instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, object-oriented code, visual code, and the like. The embodiments are not limited to such context. In a particular embodiment, the scan routine 256 may include an implant pattern processor 258 and a scan control processor 260. The implant pattern processor 258 may receive, for example, from the host interface 242 a set of substrate stress information indicative of the stress state in the film layer and / or the substrate 232. In some embodiments, the film layer is an ALN film layer. The implant pattern processor 258 may use the stress information to calculate an appropriate implant pattern to counteract the film stress and thereby produce a more uniform stress profile across the film layer and / or the substrate 232. The implant pattern information may include ion dose, ion species, implant energy, beam current, and implant tilt and / or twist. In various embodiments, a series of implant patterns may be stored in the database 262, where different implant patterns may be associated with different levels of stress across the film layer and / or the substrate 232. The scan control processor 260 may control the scanning of the substrate 232 and the scanning of the ion beam 208 to implement the implant pattern in the film layer and / or the substrate 232. Thus, in various embodiments, treating the film layer with an implant pattern to produce a lower WiW stress range in the film layer may be performed automatically or semi-automatically. Referring to FIG. 6, a non-limiting method 300 in accordance with an embodiment of the present disclosure will be described. At step 301, the method 300 may include forming a nitride film over a substrate. In some embodiments, the nitride film may be an aluminum nitride film formed by PVD. In some embodiments, the aluminum nitride film is approximately 1 micron thick as measured from the top surface of the substrate. In some embodiments, the substrate is made of silicon. At step 302, the method 300 may include performing a metrology scan of the nitride film to measure stress information of the nitride film at multiple locations. In some embodiments, a stress is measured across the entire diameter of the wafer in six (6) or more orientations using an FSM metrology tool. At step 303, the method 300 may include transforming the coordinates and stress information to determine the dose and energy of the ions for a subsequent ion implantation process to be performed. In some embodiments, the information may be used for stress correction based on a stress calibration input, which is combined with an algorithm for mapping the stress pattern to a target implant machine dose pattern in x and y or circular coordinates. At step 304, method 300 may include creating a predicted dose pattern using ion beam profile information, based on the determined dose and energy of the ions and other recipe information. In some embodiments, the dose of ion implantation varies across the nitride film based on stress information of the nitride film at each of the plurality of locations. In some embodiments, a beam profiler operable to measure certain parameters associated with the ion beam, such as beam current as a function of position, may be used to create a graph. Although non-limiting, the beam profiler may include one or more Faraday devices arranged in a linear fashion. In another embodiment, the beam profile may be measured by a plurality of Faraday devices arranged in a two-dimensional array. The Faraday devices collect current, and the beam profiler is capable of measuring the amount of current collected by each Faraday device. The controller may obtain information from the beam profiler and generate a desired dose implantation pattern. This desired dose implantation pattern may be stored as a two-dimensional array in a non-transitory storage element, where the value of each element in the array represents the desired dose at this particular location. At step 305, ion implantation is performed on the nitride film. In some embodiments, ion implantation is performed using a spot beam or a strip beam to perform both horizontal and vertical scanning of the device. Although non-limiting, the scanning is performed according to the desired dose implantation pattern and may be a combination of electrostatic, magnetic, and mechanical. In some embodiments, ion implantation includes implanting ions into a first location among the plurality of locations at a first dose and implanting ions into a second location among the plurality of locations at a second dose, where the first dose is greater than the second dose, and where a first stress value of the aluminum nitride film measured at the first location is greater than a second stress value of the aluminum nitride film measured at the second location. In some embodiments, ion implantation is performed to reduce the regional stress level of the nitride film at one or more of the plurality of locations in response to the ions being directed to the nitride film during ion implantation. In some embodiments, ion implantation includes directing at least one of the following ion species to the nitride film: B+, N+, or He+. It should be understood that other ion species may be employed in other embodiments. In optional step 306, a second metrology operation may then be performed on the nitride film to further refine the algorithm and start the stress change process again. In summary, the embodiments herein provide stress modulation in doped and undoped AlN films by variable dose ion implantation. The first advantage provided by the improvements of the embodiments described herein is that the WiW stress range is reduced to <100 MPa. The second advantage provided by the improvements of the embodiments described herein is that the crystalline columnar structure of AlN is not significantly changed, as determined by, for example, X-ray diffraction (XRD) analysis. The third advantage provided by the improvements of the embodiments described herein is that the film deposition rate of the PVD process is increased, which increases the wafer throughput. For convenience and clarity, terms such as "top", "bottom", "upper", "lower", "vertical", "horizontal", "lateral", and "longitudinal" will be understood to describe the relative placement and orientation of components and their constituent parts as they appear in the figures. The terms will include the specifically mentioned words, their derivatives, and words of similar meaning. Unless explicitly stated to exclude plural elements or operations, an element or operation stated in the singular form and preceded by the word "a" or "an" as used herein will be understood to include plural elements or operations. Additionally, reference to "one embodiment" of the present disclosure is not intended to be limiting. Additional embodiments may also include the stated features. Furthermore, in some embodiments, the terms "substantial" or "substantially" and the terms "approximate" or "approximately" may be used interchangeably and may be described using any relative measure acceptable to one of ordinary skill in the art. For example, these terms may be used as a comparison with a reference parameter to indicate a deviation that can provide the desired function. Although non-limiting, the deviation from the reference parameter may be, for example, an amount less than 1%, less than 3%, less than 5%, less than 10%, less than 15%, less than 20%, and so on. Moreover, one of ordinary skill in the art will understand that when an element such as a layer, region, or substrate is said to be formed on, deposited on, or disposed on another element "on", "above", or "over", the element may be directly on the other element, or there may also be intervening elements. In contrast, when an element is said to be "directly" on another element "on", "directly" on another element "above", or "directly" on another element "over", there are no intervening elements. As used herein, "depositing" and / or "being deposited" can include any currently known or later-developed techniques applicable to the material to be deposited, including but not limited to, for example: chemical vapor deposition (CVD), low-pressure CVD (LPCVD), and plasma-enhanced CVD (PECVD). Additional techniques can include semi-atmosphere CVD (SACVD), high density plasma CVD (HDPCVD), rapid thermal CVD (RTCVD), ultra-high vacuum CVD (UHVCVD), limited reaction processing CVD (LRPCVD), metal-organic CVD (MOCVD), and sputter deposition. Additional techniques can include ion beam deposition, electron beam deposition, laser-assisted deposition, thermal oxidation, thermal nitridation, spin coating, physical vapor deposition (PVD), atomic layer deposition (ALD), chemical oxidation, molecular beam epitaxy (MBE), plating, evaporation. The foregoing description has been presented for purposes of illustration and description and is not intended to limit the disclosure to one or more forms disclosed herein. For example, for purposes of simplifying the disclosure, various features of the disclosure can be combined together in one or more aspects, embodiments, or configurations. However, it should be understood that various features of certain aspects, embodiments, or configurations of the disclosure can be combined in alternative aspects, embodiments, or configurations. Additionally, the following claims are hereby incorporated by reference into this detailed description, with each claim standing on its own as a separate example of the disclosure. 100: Device 102, 232: Substrate 104: Nitride film 106, 127: Upper surface 108A: Location / First location 108N: Location / Second location 112: Metrology scan 120: Film stress measurement (FSM) metrology tool 125: Ion implantation 130: Graph 200: Ion implanter 204: Ion source 208: Ion beam 220: Analyzer magnet 224: Mass resolving slit (MRS) 226: Steering / focusing assembly 230: End station 231: Substrate holder 236: Beam scanner 238: Beam line 240: Controller 242: User interface / Host interface 252: Processor 254: Memory unit 256: Scan routine 258: Implant pattern processor 260: Scan control processor 262: Database 300: Method 301, 302, 303, 304, 305, 306: Steps X, Y: Axes The drawings illustrate exemplary ways of the present disclosure, including practical applications of its principles, as follows: FIG. 1 shows a side cross-sectional view of a device after depositing a film layer according to an embodiment of the present disclosure. FIG. 2A shows a side cross-sectional view of a device during wafer scanning according to an embodiment of the present disclosure. FIG. 2B shows a top view of a device during wafer scanning according to an embodiment of the present disclosure. FIG. 3 shows a side cross-sectional view of a device during ion implantation according to an embodiment of the present disclosure. FIG. 4 is a graph showing the relationship between film stress and implant dose according to an embodiment of the present disclosure. FIGS. 5A to 5B show different representations of an ion implanter consistent with various embodiments of the present disclosure. FIG. 6 is a flowchart showing a method according to an embodiment of the present disclosure. The drawings are not necessarily drawn to scale. The drawings are only schematic diagrams and are not intended to depict specific parameters of the present disclosure. The drawings are intended to illustrate exemplary embodiments of the present disclosure and should not therefore be regarded as limiting the scope. In the drawings, like reference numerals represent like elements. In addition, for clarity of illustration, some elements in some of the figures may be omitted or not drawn to scale. For clarity of illustration, cross-sectional views may be in the form of "slice" or "near-sighted" cross-sectional views and some background lines that would otherwise be visible in a "true" cross-sectional view are omitted. In addition, for clarity, some reference numerals may be omitted in some of the drawings. 300: Method 301, 302, 303, 304, 305, 306: Steps

Claims

1. A method for altering stress in a nitride film, comprising: A nitride film is formed on the substrate; A membrane stress measurement instrument is used to perform a metrological scan of the nitride membrane to measure stress information of the nitride membrane at multiple locations; and ions are directed to the nitride membrane during ion implantation, wherein the dose of ion implantation varies across the entire nitride membrane based on the stress information of the nitride membrane at each of the multiple locations, wherein the stress of the nitride membrane is modulated from tensile to compressive, and wherein the ion implantation includes scanning a dotted or striped bundle across the entire nitride membrane along a first and a second direction.

2. The method for changing the stress in a nitride film as described in claim 1, wherein the nitride film is an aluminum nitride film formed by physical vapor deposition sputtering.

3. The method of altering stress in a nitride film as described in claim 2 further includes, based on the stress information, altering the energy of the ions directed to the aluminum nitride film at each of the plurality of locations.

4. The method for changing the stress in the nitride film as described in claim 3 further includes: The ions are implanted into a first location among the plurality of locations at a first dose; And to implant the ions into a second of the plurality of locations at a second dose, wherein the first dose is greater than the second dose, and wherein a first stress value of the aluminum nitride film measured at the first location is greater than a second stress value of the aluminum nitride film measured at the second location.

5. The method for altering stress in a nitride film as described in claim 1 further includes reducing the wafer-level stress range of the nitride film by lowering the regional stress level of the nitride film at one or more of the plurality of locations in response to the ions being directed to the nitride film during the ion implantation.

6. The method of altering stress in a nitride film as claimed in claim 1, wherein guiding the ions to the nitride film during the ion implantation includes guiding at least one of the following ion species to the nitride film: B+, N+, or He+.

7. A method for altering the stress in an aluminum nitride film, the method comprising: The aluminum nitride film is formed on the substrate; A membrane stress measurement instrument is used to perform a measurement scan on the aluminum nitride membrane to measure the stress information of the aluminum nitride membrane at multiple locations. And guiding ions to the aluminum nitride membrane during ion implantation, wherein the dose of ion implantation varies across the aluminum nitride membrane based on stress information at each of the plurality of locations, wherein the stress of the aluminum nitride membrane is modulated from tensile to compressive.

8. The method for altering stress in an aluminum nitride film as described in claim 7, wherein the aluminum nitride film is formed using physical vapor deposition sputtering.

9. The method of altering stress in an aluminum nitride film as described in claim 7, further comprising altering the energy of the ions directed to the aluminum nitride film at each of the plurality of locations based on the stress information.

10. The method for changing the stress in an aluminum nitride film as described in claim 9, further comprising: The ions are implanted into a first location among the plurality of locations at a first dose; And to implant the ions into a second of the plurality of locations at a second dose, wherein the first dose is greater than the second dose, and wherein a first stress value of the aluminum nitride film measured at the first location is greater than a second stress value of the aluminum nitride film measured at the second location.

11. The method of altering stress in an aluminum nitride film as described in claim 7, further comprising reducing the regional stress level of the aluminum nitride film at one or more of the plurality of locations in response to the ions being directed to the aluminum nitride film during the ion implantation.

12. The method for altering stress in an aluminum nitride film as described in claim 7, wherein the ion implantation comprises scanning a dot bundle or a strip bundle across the entire aluminum nitride film along a first direction and a second direction.

13. The method of altering stress in an aluminum nitride film as claimed in claim 7, wherein guiding the ions to the aluminum nitride film during the ion implantation includes guiding at least one of the following ion species to the aluminum nitride film: B+, N+, or He+.

14. An apparatus for controlling membrane stress, comprising: A beam scanner that can be operated to scan an ion beam relative to a substrate; and a controller coupled to the beam scanner, the controller comprising: a processor; The controller includes a memory unit coupled to the processor and includes a scanning mode that operates on the processor to perform a metrological scan of an aluminum nitride film formed on top of the substrate using a film stress measurement instrument, thereby determining stress information of the aluminum nitride film at each of a plurality of locations. The controller is further operable to: generate a dose pattern based on the stress information of the aluminum nitride film determined for each of the plurality of locations; and guide ions to the aluminum nitride film during ion implantation, wherein the dose of the ion implantation varies across the entire aluminum nitride film based on the dose pattern, wherein the stress of the aluminum nitride film is modulated from tensile to compressive.

15. The apparatus for controlling film stress as claimed in claim 14, wherein the controller is further operable to form the aluminum nitride film using physical vapor deposition sputtering.

16. The apparatus for controlling membrane stress as claimed in claim 14, wherein the controller is further operable to change the dose and energy of the ions directed to the aluminum nitride membrane at each of the plurality of locations based on the stress information.

17. The apparatus for membrane stress control as claimed in claim 14, wherein guiding the ions to the aluminum nitride membrane during the ion implantation includes: The ions are implanted into a first location among the plurality of locations at a first dose; And to implant the ions into a second of the plurality of locations at a second dose, wherein the first dose is greater than the second dose, and wherein a first stress value of the aluminum nitride film measured at the first location is greater than a second stress value of the aluminum nitride film measured at the second location.

18. The apparatus for membrane stress control as claimed in claim 14, wherein guiding the ions to the aluminum nitride membrane during the ion implantation includes guiding at least one of the following ion species to the aluminum nitride membrane: B+, N+, or He+.

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