US 11,680,839 B2
Liquid level sensor for a chemical source vessel
Andrew Michael Yednak, III, Phoenix, AZ (US)
Assigned to ASM IP Holding B.V., Almere (NL)
Filed by ASM IP Holding B.V., Almere (NL)
Filed on Jul. 31, 2020, as Appl. No. 16/944,763.
Claims priority of provisional application 62/882,974, filed on Aug. 5, 2019.
Prior Publication US 2021/0041284 A1, Feb. 11, 2021
Int. Cl. G01F 23/263 (2022.01); G01F 23/296 (2022.01); G01F 23/292 (2006.01)
CPC G01F 23/265 (2013.01) [G01F 23/268 (2013.01); G01F 23/2961 (2013.01); G01F 23/2921 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A chemical vessel for providing a chemical precursor for use in deposition of semiconductor films onto a substrate, the chemical vessel comprising:
a vessel housing comprising a liquid level sensor port; and
a liquid level sensor tube extending vertically from a top of the vessel housing a fixed depth into the vessel housing, the liquid level sensor tube comprising:
a liquid level sensor tube housing comprising an outer surface in direct contact with a liquid chemical precursor disposed in the vessel housing and having a sealed and dry environment inside the housing that is protected from the chemical precursor, the liquid level sensor tube housing comprising a slot that extends substantially an entire length of the liquid level sensor tube housing and that is configured to accommodate placement of the liquid chemical precursor therein; and
a plurality of sensors disposed within the liquid level sensor tube housing in the sealed and dry environment and located at particular vertical locations along the liquid level sensor tube associated with particular levels of the liquid chemical precursor in the vessel housing, wherein at least one of the plurality of sensors is in contact with an inside wall surface of the liquid level tube housing.