Method and system for controlling the state of stress in deposited thin films

A closed-loop feedback control physical vapor deposition (“PVD”) system comprising:

• a chamber configured to control pressure and substrate temperature of a PVD process and to hold a substrate on which a thin film is to be deposited by a physical vapor deposition (“PVD”) process to fabricate micro-electro-mechanical systems (“MEMS”), nano-electro-mechanical systems (“NEMS”), a microelectronic device or circuit, a photonic device, micro-device or nano-device designed to meet a performance requirement that depends on stress in the thin film being deposited and a performance requirement that depends on morphology and conformality of the thin film being deposited;
• a stress monitoring system configured to measure the stress in the thin film as it is being deposited;
• a first sensor configured to measure chamber pressure;
• a second sensor configured to measure substrate temperature;
• a gridless ion gun configured to generate ions with an accelerating potential difference produced by electrons from cathode-neutralizing entering a magnetic field setup by permanent magnets in a source, and wherein acceleration of the ions takes place in a quasi-neutral plasma formed by gas ionized by the generated ions and having an approximately equal densities of electrons and ions;
• and
• a controller coupled to the stress monitoring system, the first sensor, and the second sensor, the controller configured to control the PVD system to at least:
• set a process pressure of the chamber, a substrate temperature, a target sputter power density, sputter signal frequency, and sputter signal duty cycle for the PVD process;
• (a) during the deposition of the thin film on the substrate at the set pressure and the set substrate temperature of the PVD process, determine, based on information received from the stress monitoring system, whether excessive stress level in the thin film can be changed towards a level of zero stress by (i) adjusting the set process pressure at which the thin film is deposited on the substrate so as to be within a predetermined pressure process window between 10−3 to 10−9 Torr, or (ii) adjusting the set temperature of the substrate on which the thin film is deposited to be within a predetermined temperature process window that is below 0 degrees C. or greater than 250 degrees C.;
• (b) upon determining in step (a) that the excessive stress level in the thin film cannot be changed from being excessive and towards a level of zero stress by adjusting the set process pressure and that the excessive stress level in the thin film cannot be changed towards a level of zero stress by adjusting the temperature of the substrate, while maintaining the set process pressure and the set temperature of the substrate, adjust the set target sputter power density within a predetermined target power density process window between 2 and 10 W/cm2 for varying the target power density to thereby adjust the thin film stress to not be excessive and moved towards a level of zero stress and thin film conformality to not be in one or more of undesired states, and then determine whether adjusting the set target sputter power density within the predetermined target power density process window will keep the stress in the thin film to be excessive and make the thin film conformality to be in one or more of the undesired states;
• c) upon determining in step (b) that adjusting the target sputter power density within the predetermined target power density process window will keep the stress in the thin film to be excessive and will make the thin film conformality to be in one or more of the undesired states, while maintaining the set target sputter power density adjusted in step (b), adjusting the set sputter signal frequency within a predetermined sputter signal frequency process window between 0 to 13.56 MHz for varying the sputter signal frequency to thereby adjust thin film stress to not be excessive and moved towards a level of zero stress and thin film conformality to not be in one or more of the undesired states, and then determining whether adjusting the sputter signal frequency within the predetermined sputter signal frequency process window will keep the stress in the thin film to be excessive and make the thin film conformality to be in one or more of the undesired states;
• (d) upon determining in step (c) that adjusting the sputter signal frequency within the predetermined sputter signal frequency process window will keep the stress in the thin film to be excessive and will make the thin film conformality to be in one or more of the undesired states, then while maintaining the set target sputter power density adjusted in step (b) and set sputter signal frequency adjusted in step (c), adjust sputter signal duty cycle within a predetermined sputter signal duty cycle process window between 5 and 100% for varying the sputter signal duty cycle to thereby adjust film stress to not be excessive and moved towards a level of zero stress and thin film conformality to not be in one or more of the undesired states, and then determining whether adjusting the sputter signal duty cycle within the predetermined sputter signal duty cycle process window for varying the sputter signal duty cycle will keep the stress in the thin film to be excessive and/or make the thin film conformality to be in one or more of the undesired states,
• (e) upon determining that adjusting the sputter signal duty cycle within the predetermined sputter signal duty cycle process window will keep the stress in the thin film to be excessive and/or make the thin film conformality to be in one or more of the undesired states, then repeat steps (b) to (d) so that the thin film stress is changed to not be excessive and moved towards a level of zero stress;
• (f) determine whether limits for adjusting the set target sputter power density, the set sputter signal frequency, and the set sputter signal duty cycle have been reached on sputter power supply;
• (g) upon determining that the limits for adjusting the set target sputter power density, the set sputter signal frequency, and the set sputter signal duty cycle limits have been reached on the sputter power supply, determine if the set process pressure and the set substrate temperature can be further adjusted to change the thin film stress level from being excessive and towards a level of zero stress;
• and
• (h) upon determining that the set process pressure and the set substrate temperature can be further adjusted to reduce the stress of the thin film towards a level of zero stress, adjust the set process pressure at which the thin film is deposited to be within the predetermined pressure process window and the set temperature of the substrate on which the thin film is deposited to be within the predetermined temperature process window, and then repeat steps (b) to (d) to change the stress in the thin film from being excessive and towards a level of zero stress,
• wherein the thin film being deposited on the substrate is a layer of a multilayer thin film structure including at least one sacrificial thin film layer onto which the thin film layer is deposited, and at least a portion of the thin film layer is attached to the substrate, and
• wherein the substrate temperature is lowered through cooling of the substrate using liquid nitrogen or chilled water and the substrate temperature is increased through heating the substrate with a resistive heater in contact with the substrate or by irradiation of the substrate from a source of infrared radiation or visible wavelengths.

A method of controlling stress in a thin film while the thin film is being deposited over pre-existing topography of a substrate by a physical vapor deposition (“PVD”) process on a substrate to fabricate a micro-electro-mechanical system (“MEMS”), a nano-electro-mechanical system (“NEMS”), a photonic device, a micro-device or a nano-device designed to meet a performance requirement that depends on the stress in the thin film being deposited and a performance requirement that depends on morphology of the thin film being deposited and conformality of the thin film being deposited over the pre-existing topography of the substrate, the method comprising:

• set a pressure of a chamber configured to control the PVD process and a substrate temperature for the PVD process;
• during the deposition of the thin film on the substrate at the set pressure and the set substrate temperature of the PVD process, determining, based on measurements received from a stress monitoring system during the deposition of the thin film, whether the stress in the thin film being deposited causes the performance requirement which depends on the stress in the thin film to be not satisfied;
• upon determining that the stress in the thin film being deposited at the set pressure and the set substrate temperature will not cause the performance requirement which depends on the stress in the thin film to be not satisfied, control the deposition of the thin film on the substrate at the set pressure and the set substrate temperature of the PVD process without adjusting current and voltage for an ion bombardment of the thin film;
• upon determining that the stress in the thin film being deposited at the set pressure and the set substrate temperature causes the performance requirement which depends on the stress in the thin film to be not satisfied, determining whether adjusting the set pressure within a predetermined pressure process window between 10−3 to 10−9 Torr will change the stress of the thin film towards zero stress;
• upon determining that adjusting the set pressure within the predetermined pressure process window will change the stress of the thin film towards zero stress, adjusting the set pressure within the predetermined pressure process window and determining whether adjusting the set pressure within the predetermined pressure process window will change the morphology of the thin film being deposited and the conformality of the thin film being deposited over the pre-existing topography of the substrate such that the performance requirement which depends on the morphology of the thin film being deposited and the conformality of the thin film over the pre-existing topography of the substrate is not satisfied;
• upon determining that adjusting the set pressure within the predetermined pressure process window will not change the morphology of the thin film being deposited and the conformality of the thin film being deposited such that the performance requirement which depends on the morphology of the thin film being deposited and the conformality of the thin film is not satisfied, adjusting the set pressure within the predetermined pressure process window to change the stress of the thin film towards zero stress and control the deposition of the thin film on the substrate at the adjusted pressure and the set substrate temperature of the PVD process;
• upon determining that adjusting the set pressure within the predetermined pressure process window will change the morphology of the thin film being deposited and the conformality of the thin film being deposited over the pre-existing topography of the substrate such that the performance requirement which depend on the morphology of the thin film being deposited and the conformality of the thin film is not satisfied, determining whether adjusting the set substrate temperature within a predetermined temperature process window between −100° to +800° C. will change the stress of the thin film towards zero stress;
• upon determining that adjusting the set substrate temperature within the predetermined temperature process window will change the stress of the thin film towards zero stress, determining whether adjusting the substrate temperature within the predetermined temperature process window will change the morphology of the thin film being deposited and the conformality of the thin film being deposited such that the performance requirement which depends on the morphology of the thin film being deposited and the conformality of the thin film is not satisfied;
• and
• upon determining that adjusting the substrate temperature within the predetermined temperature process window will change the morphology of the thin film being deposited and the conformality of the thin film being deposited such that the performance requirement which depends on the morphology of the thin film being deposited and the conformality of the thin film is not satisfied, separately control current and voltage of a gridless ion gun configured to bombard the thin film with ions during the deposition of the thin film on the substrate to reduce the energy in the thin film and thereby the stress in the thin film while making no further changes in the process pressure or in the substrate temperature, wherein the gridless ion gun configured to generate ions with an accelerating potential difference produced by electrons from cathode-neutralizer entering a magnetic field setup by permanent magnets in a source, and wherein acceleration of the ions takes place in a quasi-neutral plasma formed by gas ionized by the generated ions and having an approximately equal densities of electrons and ions,
• wherein the substrate temperature is lowered through cooling of the substrate using liquid nitrogen or chilled water and the substrate temperature is increased through heating the substrate with a resistive heater in contact with the substrate or by irradiation of the substrate from a source of infrared radiation or visible wavelengths.

A closed-loop feedback control method of controlling stress in a thin film with an excessive stress level while the thin film is being deposited over pre-existing topography of a substrate by an evaporated physical vapor deposition (“PVD”) process on a substrate to fabricate a micro-electro-mechanical system (“MEMS”), a nano-electro-mechanical system (“NEMS”), a photonic device, a micro-device or a nano-device on the substrate, the evaporated PVD process includes depositing the thin film on the substrate at a set process pressure and a set temperature of the substrate, and using t a gridless ion gun to bombard the thin film with ions at a set ion gun current and a set ion gun voltage, the stress in the thin film being deposited being determined during the deposition of the thin film based on measurements received from a stress monitoring system during the deposition of the thin film over the pre-existing topography of the substrate, wherein the gridless ion gun configured to generate ions with an accelerating potential difference produced by electrons from cathode-neutralizer entering a magnetic field setup by permanent magnets in a source, and wherein acceleration of the ions takes place in a quasi-neutral plasma formed by gas ionized by the generated ions and having an approximately equal densities of electrons and ions, the method comprising;

• (a) determining whether the excessive stress level in the thin film can be changed from being excessive and towards zero stress by (i) adjusting the set process pressure at which the thin film is deposited on the substrate so as to be within a predetermined pressure process window between 10−3 to 10−9 Torr, or (ii) adjusting the set temperature of the substrate on which the thin film is deposited to be within a predetermined temperature process window between −100° to +800° C.;
• (b) upon determining in step (a) that the excessive stress level in the thin film cannot be changed from being excessive and towards zero stress by adjusting the set process pressure and that the excessive stress level in the thin film cannot be changed from being excessive and towards zero stress by adjusting the temperature of the substrate, while maintaining the set process pressure, the set temperature of the substrate and the set ion gun voltage, increasing tensile stress in the thin film being deposited by decreasing the set ion gun current below a predetermined first current level above 2 amps or increasing compressive stress in the thin film being deposited by increasing the set ion gun current above a predetermined first current range, and then determining whether the stress in the thin film being deposited can be moved towards zero stress as the set ion gun current is varied within a predetermined ion gun current process window above 2 amps for varying the ion gun current;
• c) upon determining that the stress in the thin film being deposited cannot be moved towards zero stress as the ion gun current is varied within the predetermined ion gun current process window, increasing, while maintaining the set ion gun current adjusted in step (b), the tensile stress in the thin film being deposited by decreasing the set ion gun voltage below a first voltage level or increasing compressive stress by increasing the set ion gun voltage above a second voltage level, and then determining whether the stress in the thin film being deposited can be moved towards zero stress as the ion gun voltage is varied within a predetermined ion gun voltage process window between 100 and 300 volts for varying the ion gun voltage;
• (d) upon determining in step (c) that the thin film stress cannot be moved towards zero stress as the ion gun voltage is varied within the ion gun voltage process window, adjusting the set ion gun acceleration voltage to be within the predetermined ion gun voltage process window, and then repeating steps (a) to (c)
• (e) upon determining a plurality of times that the thin film stress cannot be moved away from being excessive and towards zero stress as the ion gun current and voltage are varied within the predetermined ion gun current process window and within the predetermined ion gun voltage process window, respectively,
• while maintaining the set ion gun current adjusted in step (b) and the set ion gun voltage adjusted in step (c), adjusting the process pressure at which the thin film is deposited to be within the predetermined process pressure window and the temperature of the substrate on which the thin film is deposited to be within the substrate temperature process window;
• and
• (f) after performing step (e), repeating steps (b) to (e) to change the stress in the thin film from being excessive and towards zero stress,
• wherein the substrate temperature is lowered through cooling of the substrate using liquid nitrogen or chilled water and the substrate temperature is increased through heating the substrate with a resistive heater in contact with the substrate or by irradiation of the substrate from a source of infrared radiation or visible wavelengths.

A closed-loop feedback control method of controlling stress in a thin film with an excessive stress level while the thin film is being deposited over a pre-existing topography of a substrate by sputtering physical vapor deposition (“PVD”) on a substrate to fabricate a micro-electro-mechanical system (“MEMS”), a nano-electro-mechanical system (“NEMS”), a photonic device, a micro-device or a nano-device on the substrate, the sputtering PVD process includes using an gridless ion gun to bombard the thin film with ions during the deposition of the thin film on the substrate and depositing the thin film on the substrate at a set process pressure, a set temperature of the substrate, a set target sputter power density, a set sputter signal frequency and a set sputter signal duty cycle, the stress in the thin film being deposited being determined during the deposition of the thin film based on measurements received from a stress monitoring system during the deposition of the thin film over the pre-existing topography of the substrate, wherein the gridless ion gun configured to generate ions with an accelerating potential difference produced by electrons from cathode-neutralizer entering a magnetic field setup by permanent magnets in a source, and wherein acceleration of the ions takes place in a quasi-neutral plasma formed by gas ionized by the generated ions and having an approximately equal densities of electrons and ions, the method comprising;

• (a) determining whether the excessive stress level in the thin film can be changed from being excessive and towards a desired state of stress by (i) adjusting the set process pressure at which the thin film is deposited on the substrate so as to be within a predetermined pressure process window between 10−3 to 10−9 Torr, or (ii) adjusting the set temperature of the substrate on which the thin film is deposited to be within a predetermined temperature process window;
• (b) upon determining in step (a) that the excessive stress level in the thin film cannot be changed from being excessive and towards the desired state of stress by adjusting the set process pressure and that the excessive stress level in the thin film cannot be changed from being excessive and towards the desired state of stress by adjusting the temperature of the substrate, while maintaining the set process pressure and the set temperature of the substrate, adjusting the set target sputter power density within a predetermined target power density process window for varying the target power density to thereby adjust the thin film stress towards the desired state of stress and/or thin film conformality to not be in one or more of the undesired states, and then determining whether adjusting the target sputter power density within the predetermined target power density process window will keep the stress in the thin film to be excessive and/or make the thin film conformality to be in one or more of the undesired states;
• c) upon determining in step (b) that adjusting the target sputter power density within the predetermined target power density process window will keep the stress in the thin film to be excessive and/or will make the thin film conformality to be in one or more of the undesired states, while maintaining the set target sputter power density adjusted in step (b), adjusting the set sputter signal frequency within a predetermined sputter signal frequency process window for varying the sputter signal frequency to thereby adjust the thin film stress towards the desired state of stress and/or thin film conformality over the pre-existing topography of the substrate to not be in one or more of the undesired states, and then determining whether adjusting the sputter signal frequency within the predetermined sputter signal frequency process window will keep the stress in the thin film to be excessive and/or make the thin film conformality over a pre-existing topography of the substrate to be in one or more of the undesired states;
• (d) upon determining in step (c) that adjusting the sputter signal frequency within the predetermined sputter signal frequency process window will keep the stress in the thin film to be excessive and/or will make the thin film conformality over the pre-existing topography of the substrate to be in one or more of the undesired states, then while maintaining the set target sputter power density adjusted in step (b) and set sputter signal frequency adjusted in step (c), adjusting sputter signal duty cycle within a predetermined sputter signal duty cycle process window for varying the sputter signal duty cycle to thereby adjust film stress towards the desired state of stress and/or thin film conformality over the pre-existing topography of the substrate to not be in one or more of the undesired states, and then determining whether adjusting the sputter signal duty cycle within the predetermined sputter signal duty cycle process window for varying the sputter signal duty cycle will keep the stress in the thin film to be excessive and/or make the thin film conformality over the pre-existing topography of the substrate to be in one or more of the undesired states,
• (e) upon determining that adjusting the sputter signal duty cycle within the predetermined sputter signal duty cycle process window will keep the stress in the thin film to be excessive and/or make the thin film conformality over the pre-existing topography of the substrate to be in one or more of the undesired states, then repeating steps (b) to (d) so that the thin film stress is moved towards the desired state of stress;
• (f) determining whether limits for adjusting the set target sputter power density, the set sputter signal frequency, and the set sputter signal duty cycle have been reached on sputter power supply;
• (g) upon determining that the limits for adjusting the set target sputter power density, the set sputter signal frequency, and the set sputter signal duty cycle limits have been reached on the sputter power supply, determining if the set process pressure and/or the set substrate temperature can be further adjusted to change the thin film stress level from being excessive and towards the desired state of stress;
• and
• (h) upon determining that the set process pressure and/or the set substrate temperature can be further adjusted to reduce the stress of the thin film towards the desired state of stress, adjusting the set process pressure at which the thin film is deposited to be within the predetermined process pressure window and/or the set temperature of the substrate on which the thin film is deposited to be within the predetermined temperature process window, and then repeating steps (b) to (d) to change the stress in the thin film from being excessive and towards the desired state of stress,
• wherein the substrate temperature is lowered through cooling of the substrate using liquid nitrogen or chilled water and the substrate temperature is increased through heating the substrate with a resistive heater in contact with the substrate or by irradiation of the substrate from a source of infrared radiation or visible wavelengths.

A method of controlling stress in a thin film with an excessive stress level while the thin film is being deposited by physical vapor deposition (“PVD”) on a substrate to fabricate micro-electro-mechanical systems (“MEMS”), nano-electro-mechanical systems (“NEMS”), a photonic device, micro-device or nano-device on the substrate, the method comprising:

• a) determining whether or not a morphology or conformality or morphology and conformality of the thin film being deposited is/are such that a system or device fabricated with the thin film will function as designed,
• b) based on determining that the morphology or conformality or morphology and conformality of the thin film being deposited is/are such that the system or device being fabricated will function as designed, then determining whether or not adjusting a pressure at which the thin film is deposited will change the thin film's morphology or conformality or morphology and conformality to one or more states, wherein the system or device fabricated with the changed thin film will not function as designed,
• c) based on determining that adjusting the pressure at which the thin film is deposited will not change the thin film's morphology or conformality or morphology and conformality to the one or more states wherein the system or device fabricated with the thin film will not function as designed, then adjusting the deposition pressure over a predetermined pressure process window to change the thin film stress level from being excessive and towards a level of zero stress,
• d) determining whether or not the thin film stress level can be controlled so as to not be excessive, while maintaining the process pressure within the predetermined pressure process window, and based on determining that the thin film stress level can be controlled so as to not be excessive, then adjusting the process pressure accordingly within the predetermined pressure process window to thereby change the thin film stress level from being excessive and towards a level of zero stress,
• e) based on determining that the thin film stress level cannot be controlled so as to not be excessive while the process pressure is maintained within the predetermined pressure process window, or based on determining that adjusting the process pressure will change the thin film's morphology or conformality or morphology and conformality to the one or more states wherein the system or device fabricated with the thin film will not function as designed, determining whether a higher or lower substrate temperature can be used to change the thin film stress level from being excessive and towards a level of zero stress,
• f) based on determining that the higher or lower substrate temperature cannot be used, while making no further changes in the process pressure or in the substrate temperature, using ion bombardment of the thin film by a gridless ion gun to reduce energy in the thin film and thereby the stress in the thin film, wherein the gridless ion gun configured to generate ions with an accelerating potential difference produced by electrons from cathode-neutralizer entering a magnetic field setup by permanent magnets in a source, and wherein acceleration of the ions takes place in a quasi-neutral plasma formed by gas ionized by the generated ions and having an approximately equal densities of electrons and ions,
• g) based on determining that the higher or lower substrate temperature can be used, determining whether adjusting the substrate temperature will change the thin film's morphology or conformality or morphology and conformality to the one or more states wherein the system or device fabricated with the thin film will not function as designed,
• h) based on determining that a higher or lower substrate temperature will change the thin film's morphology or conformality or morphology and conformality to the one or more states wherein the system or device fabricated with the changed thin film will not function as designed, using ion bombardment of the thin film by the ion gun, while making no further changes in the process pressure or in the substrate temperature, to reduce the energy in the thin film and thereby the stress in the thin film,
• i) based on determining that a higher or lower substrate temperature will not change the thin film's morphology, or conformality or morphology and conformality to the one or more states wherein the system or device fabricated with the thin film will not function as designed, and based on determining that increasing tensile stress in the thin film by decreasing substrate temperature, or increasing compressive stress in the thin by increasing substrate temperature enables the thin film stress level to be changed from being excessive and towards a level of zero stress, then adjusting the substrate temperature accordingly within a predetermined temperature process window for varying the process temperature to thereby change the thin film stress level from being excessive and towards the level of zero stress, and
• j) based on determining that adjusting the substrate temperature within a predetermined temperature process window for varying the substrate temperature does not result in a change in the thin film stress level from being excessive and towards the level of zero stress, using ion bombardment of the thin film by the ion gun, while making no further changes in the process pressure or in the substrate temperature, to reduce the energy in the thin film and thereby the stress in the thin film from being excessive and towards the level of zero stress,
• wherein the substrate temperature is lowered through cooling of the substrate using liquid nitrogen or chilled water and the substrate temperature is increased through heating the substrate with a resistive heater in contact with the substrate or by irradiation of the substrate from a source of infrared radiation or visible wavelengths.

A method of controlling stress in a thin film with an excessive stress level while the thin film is being deposited by evaporated physical vapor deposition (“PVD”) on a substrate to fabricate a micro-electro-mechanical systems (“MEMS”), nano-electro-mechanical systems (“NEMS”), photonic, micro-device or nano-device on the substrate, where the excessive stress level could not be changed from being excessive and towards a level of zero stress by adjusting (i) a process pressure at which the thin film is deposited on a substrate so as to be within a predetermined pressure process window, or (ii) a substrate temperature of the substrate on which the thin film is deposited to be within a predetermined temperature process window, and where a gridless ion gun is being used to bombard the thin film with ions, wherein the gridless ion gun configured to generate ions with an accelerating potential difference produced by electrons from cathode-neutralizer entering a magnetic field setup by permanent magnets in a source, and wherein acceleration of the ions takes place in a quasi-neutral plasma formed by gas ionized by the generated ions and having an approximately equal densities of electrons and ions, the method comprising:

• a) increasing tensile stress in the thin film being deposited by decreasing ion gun current below a predetermined first current level, or increasing compressive stress in the thin film being deposited by increasing the ion gun current above a predetermined first current range, and then determining if the stress in the thin film being deposited can be moved towards a level of zero stress as the ion gun current is varied within a predetermined ion gun current process window for varying the ion gun current,
• b) based on determining that the stress in the thin film being deposited can be moved towards a level of zero stress as the ion gun current is varied within the predetermined ion gun current process window, while not changing ion gun's acceleration voltage, adjusting the ion gun current accordingly so that the thin film stress is changed to not be excessive and moved towards a level of zero stress,
• c) based on determining that the stress in the thin film being deposited cannot be moved towards a level of zero stress as the ion gun current is varied within the ion gun current process window, and increasing tensile stress in the thin film being deposited by decreasing ion gun voltage below a first voltage level or increasing compressive stress by increasing ion gun voltage above a second voltage level, and then determining if the stress in the thin film being deposited can be moved towards a level of zero stress as the ion gun voltage is varied within a predetermined ion gun voltage process window for varying the ion gun voltage,
• d) based on determining that the thin film stress can be moved towards a level of zero stress as the ion gun voltage is varied within the predetermined ion gun voltage process window, then while not changing the ion gun's current, adjusting the ion gun acceleration voltage accordingly within the predetermined ion gun voltage process window so that the thin film stress is changed to not be excessive and moved towards a level of zero stress,
• e) based on determining that the thin film stress cannot be moved towards a level of zero stress as the ion gun voltage is varied within the ion gun voltage process window, adjusting and fixing the ion gun acceleration voltage to be within the predetermined ion gun voltage process window, and then repeating steps (a) to (d) until a determination has been made that the thin film stress is either moved away from being excessive and towards the level of zero stress or not moved away from being excessive and towards the level of zero stress a plurality of times,
• f) based on determining a plurality of times that the thin film stress cannot be moved away from being excessive and towards the level of zero stress as the ion gun current and/or voltage is/are varied within the predetermined ion gun current process window and within the predetermined ion gun voltage process window, respectively, determining if the ion gun's current and/or voltage limits have been reached, and
• g) based on the current and/or voltage limits being reached on the ion gun, determining if the process pressure and/or the substrate temperature can be further adjusted to change the thin film stress level from being excessive and towards a level of zero stress,
• h) based on determining that the process pressure and/or the substrate temperature cannot be further adjusted, exploring other physical vapor deposition techniques to control the thin film stress,
• i) based on determining that the process pressure and/or the substrate temperature can be further adjusted, adjusting the process pressure at which the thin film is deposited to be within the predetermined process pressure window and/or the temperature of the substrate on which the thin film is deposited to be within the substrate temperature process window, then repeating steps (a) to (h) until either a determination has been made that the thin film stress level is changed from being excessive and towards a level of zero stress, or not, and then a determination has been made that the process pressure and/or the substrate temperature cannot be further adjusted, such that other physical vapor deposition techniques to control the thin film stress should be explored,
• wherein the substrate temperature is lowered through cooling of the substrate using liquid nitrogen or chilled water and the substrate temperature is increased through heating the substrate with a resistive heater in contact with the substrate or by irradiation of the substrate from a source of infrared radiation or visible wavelengths.

A method of controlling stress in a thin film with an excessive stress level while the thin film is being deposited by sputtering evaporated physical vapor deposition (“PVD”) on a substrate to fabricate a micro-electro-mechanical systems (“MEMS”), nano-electro-mechanical systems (“NEMS”), photonic, micro-device or nano-device on the substrate, where the excessive stress level could not be changed from being excessive and towards a level of zero stress by adjusting (i) a process pressure at which the thin film is deposited on a substrate so as to be within a predetermined pressure process window, or (ii) a substrate temperature of the substrate on which the thin film is deposited to be within a predetermined temperature process window, and where the thin film is being bombarded by ions from a gridless ion gun, wherein the gridless ion gun configured to generate ions with an accelerating potential difference produced by electrons from cathode-neutralizer entering a magnetic field setup by permanent magnets in a source, and wherein acceleration of the ions takes place in a quasi-neutral plasma formed by gas ionized by the generated ions and having an approximately equal densities of electrons and ions, the method comprising:

• a) adjusting target sputter power density in an attempt for it to be within a predetermined target power density process window for varying the target power density to thereby adjust thin film stress to not be excessive and moved towards a level of zero stress and/or thin film conformality to not be in one or more of the undesired states, and then determining if the target sputter power density is or is not within the predetermined target power density process window,
• b) based on determining that the target sputter power density is within the target power density process window, then while not changing all other process parameters, adjusting sputter power density accordingly within the predetermined target power density process window so that the thin film stress is changed to not be excessive and moved towards a level of zero stress,
• c) based on determining that the adjusted target sputter power density is not within the predetermined target power density process window, then while not changing target sputter power density, adjusting sputter signal frequency in an attempt for it to be within a predetermined sputter signal frequency process window for varying the sputter signal frequency to thereby adjust thin film stress to not be excessive and moved towards a level of zero stress and/or thin film conformality to not be in one or more of the undesired states, and then determining if the sputter signal frequency is or is not within the predetermined sputter signal frequency process window,
• d) based on determining that the sputter signal frequency is within the sputter signal frequency process window, then while not changing all other process parameters, adjusting sputter signal frequency accordingly within the predetermined sputter signal frequency process window so that the thin film stress is changed to not be excessive and moved towards a level of zero stress,
• e) based on determining that the sputter signal frequency is not within the predetermined sputter signal frequency process window, then while not changing target sputter power density and sputter signal frequency, adjusting sputter signal duty cycle in an attempt for it to be within a predetermined sputter signal duty cycle process window for varying the sputter signal duty cycle to thereby adjust film stress to not be excessive and moved towards a level of zero stress and/or thin film conformality to not be in one or more of the undesired states, and then determining if the sputter signal duty cycle is within a predetermined sputter signal duty cycle process window for varying the sputter signal duty cycle,
• f) based on determining that the sputter signal duty cycle is within the predetermined sputter signal duty cycle process window, then while not changing all other parameters, adjusting sputter signal duty cycle accordingly within the predetermined sputter signal duty cycle process window so that the thin film stress is changed to not be excessive and moved towards a level of zero stress,
• g) based on determining that the sputter signal duty cycle is not within the predetermined sputter signal duty cycle process window, then repeating steps (a) to (e) until the sputter signal duty cycle is within the predetermined sputter signal duty cycle process window so that the thin film stress is changed to not be excessive and moved towards a level of zero stress or not within the predetermined sputter signal duty cycle process window a plurality of times, and
• h) based on determining a plurality of times that the sputter signal duty cycle is not within the predetermined sputter signal duty cycle process window, then determining whether or not target sputter power density, sputter signal frequency, and sputter signal duty cycle limits have been reached on sputter power supply, and
• i) based on determining that target sputter power density, sputter signal frequency, and sputter signal duty cycle limits have been reached on sputter power supply, then determining if the process pressure and/or the substrate temperature can be further adjusted to change the thin film stress level from being excessive and towards a level of zero stress,
• j) based on determining that the process pressure and/or the substrate temperature cannot be further adjusted, exploring other physical vapor deposition techniques to control the thin film stress,
• k) based on determining that the process pressure and/or the substrate temperature can be further adjusted, adjusting the process pressure at which the thin film is deposited to be within the predetermined process pressure window and/or the temperature of the substrate on which the thin film is deposited to be within the substrate temperature process window, then repeating steps (a) to (j) until a determination has been made that either the thin film stress level is changed from being excessive and towards a level of zero stress, or not, and a determination has been made that the process pressure and/or the substrate temperature cannot be further adjusted, such that other physical vapor deposition techniques to control the thin film stress should be explored,
• wherein the substrate temperature is lowered through cooling of the substrate using liquid nitrogen or chilled water and the substrate temperature is increased through heating the substrate with a resistive heater in contact with the substrate or by irradiation of the substrate from a source of infrared radiation or visible wavelengths.