US 11,942,897 B2
Crystal oscillator, and method for making the same
Ray-Hua Horng, Taichung (TW); and Yi-Lun Lin, Taichung (TW)
Assigned to NATIONAL YANG MING CHIAO TUNG UNIVERSITY, Hsinchu (TW); and AKER TECHNOLOGY CO., LTD., Taichung (TW)
Filed by National Yang Ming Chiao Tung University, Hsinchu (TW); and AKER TECHNOLOGY CO., LTD., Taichung (TW)
Filed on Aug. 30, 2022, as Appl. No. 17/898,747.
Claims priority of application No. 110132308 (TW), filed on Aug. 31, 2021.
Prior Publication US 2023/0061409 A1, Mar. 2, 2023
Int. Cl. H03B 5/32 (2006.01); H10N 30/06 (2023.01); H10N 30/082 (2023.01)
CPC H03B 5/32 (2013.01) [H10N 30/06 (2023.02); H10N 30/082 (2023.02); H03B 2200/0022 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method for making a crystal oscillator, comprising the steps of:
a) forming a first electrode portion on a surface of a piezoelectric substrate, so as to obtain a first semi-finished product;
b) attaching the first semi-finished product on a temporary substrate with the first electrode portion facing the temporary substrate;
c) thinning the piezoelectric substrate of the first semi-finished product, so as to obtain a thinned piezoelectric substrate having a first thickness and having a first surface on which the first electrode portion is formed;
d) forming a second electrode on a second surface of the thinned piezoelectric substrate opposite to the temporary substrate, the second electrode including a second electrode portion having at least one opening, and a second extending electrode portion extending outwardly from the second electrode portion and disposed on a peripheral region of the thinned piezoelectric substrate, a projection of the second electrode portion on the second surface of the thinned piezoelectric substrate partially overlapping a projection of the first electrode portion on the second surface of the thinned piezoelectric substrate;
e) forming a first extending electrode portion that extends from the first electrode portion along a side surface of the thinned piezoelectric substrate to the second surface of the thinned piezoelectric substrate;
f) forming a hollow frame on the second surface of the thinned piezoelectric substrate, the hollow frame surrounding the second electrode portion, and disposed on the second extending electrode portion; and
g) etching a portion of the thinned piezoelectric substrate in positional correspondence with the at least one opening using the second electrode as a mask.