Patent ID: 9053929
Filing Date: 2015-06-09
Classification: B81B,B81C,C23C,H01L

Abstract:
1. A method of controlling excessive stress beyond a predetermined range of stress in thin films being deposited by physical vapor deposition (“PVD”) on substrates containing previously fabricated microelectronics to fabricate micro-electro-mechanical systems (“MEMS”), nano-electro-mechanical systems (“NEMS”), photonic, micro-devices or nano-devices on the substrates, the method comprising the steps of: a) determining whether changes in the thin films' morphology or conformality or morphology and conformality degree(s) is/are tolerable with regard to the micro- or nano-devices fabricated from the thin films being able to function as designed, b) for thin films where changes in their morphology or conformality or morphology and conformality degree(s) is/are intolerable, determining whether adjusting thin film deposition process pressure will change their degree(s) of morphology or conformality or morphology and conformality, such that the micro- or nano-devices fabricated with the changed thin films will not function as designed, c) for thin films where adjusting the thin film deposition pressure will not change their degree(s) of morphology or conformality or morphology and conformality, such that the fabricated micro- or nano-devices will function as designed, adjusting the thin film deposition process pressure within a predetermined pressure process window to change the thin film stress level from being excessive and towards zero stress, d) for thin films where changes in their degree(s) of morphology or conformality or morphology and conformality is/are tolerable, where thin film tensile stress is to be increased, increasing the process pressure to change the thin film stress level, and where thin film compressive stress is to be increased, decreasing the process pressure to change the thin film stress level, and then determining whether achieving a thin film stress level towards zero is within a predetermined pressure process window, e) for thin films where stress level can not be controlled so as to not be excessive while the process pressure is maintained within the predetermined pressure process window, or where adjusting the process pressure will change their degree(s) of morphology or conformality or morphology and conformality, such that the fabricated micro- or nano-devices will not function as designed, determining whether a higher or lower substrate temperature will change the thin film stress level from being excessive and towards a level of zero stress, f) for thin films where a higher or lower substrate temperature can not be used to change the thin film stress level, while making no further changes in the process pressure or in the substrate temperature, using thin film ion bombardment to reduce thin film energy and thereby thin film stress, g) for thin films where a higher or lower substrate temperature can be used to change thin film stress level, determining whether adjusting substrate temperature will change their degree(s) morphology or conformality or morphology and conformality, such that the fabricated micro- or nano-devices will not function as designed, h) for thin films where a higher or lower substrate temperature will change their degree(s) of morphology, conformality or morphology and conformality, such that the fabricated micro- or nano-devices will not function as designed, using thin film ion bombardment, while making no further changes in the process pressure or in the substrate temperature, to reduce thin film energy and thereby thin film stress, i) for thin films where the higher or lower substrate temperature will not change their degree(s) of morphology or conformality or morphology and conformality, such that the fabricated micro- or nano-devices will function as designed, and where increasing thin film tensile stress by decreasing substrate temperature, or increasing thin film compressive stress by increasing substrate temperature enables the thin film stress level to be changed from being excessive and towards the level of zero stress, adjusting the substrate temperature within a temperature process window to thereby change the thin film stress level from being excessive and towards the level of zero stress, j) for thin films where adjusting the substrate temperature within a predetermined temperature process window will not result in a change in the thin film stress level from being excessive and towards zero stress, using thin film ion bombardment using an ion gun, while making no further changes in the process pressure or in the substrate temperature, to reduce thin film energy and thereby thin film stress, and k) maintaining substrate temperature below a temperature that would result in the previously fabricated micro- or nano-devices not functioning as designed.