US 12,232,254 B2
Printed circuit board and manufacturing method thereof
Po-Hsiang Wang, Taoyuan (TW); and Ming-Hao Wu, Taoyuan (TW)
Assigned to Unimicron Technology Corporation, Taoyuan (TW)
Filed by Unimicron Technology Corporation, Taoyuan (TW)
Filed on Aug. 3, 2022, as Appl. No. 17/879,920.
Claims priority of application No. 111122549 (TW), filed on Jun. 17, 2022.
Prior Publication US 2023/0413430 A1, Dec. 21, 2023
Int. Cl. H05K 1/02 (2006.01); H05K 1/09 (2006.01); H05K 3/00 (2006.01); H05K 3/26 (2006.01); H05K 3/32 (2006.01); H05K 3/46 (2006.01)
CPC H05K 1/0298 (2013.01) [H05K 1/092 (2013.01); H05K 3/0017 (2013.01); H05K 3/26 (2013.01); H05K 3/321 (2013.01); H05K 3/4664 (2013.01); H05K 2201/09227 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A printed circuit board comprising:
a first substrate having a first surface and a second surface, the first surface and the second surface being parallel to each other relative to an axis;
a first circuit layer formed on at least one of the first surface and the second surface of the first substrate, the first circuit layer having a first trace and a first gap beside the first trace by etching, wherein an etching factor of the first trace is greater than or equal to 2.3; and
a second circuit layer formed on the first circuit layer, the second circuit layer disposed on a surface of a second substrate, the second circuit layer having a second trace and a second gap beside the second trace by etching, wherein an etching factor of the second trace is greater than or equal to 2.3;
wherein the first trace and the second trace are connected with each other along the axis in order to form a stacked trace, and an etching factor of the stacked trace is greater than or equal to 4.6;
wherein a low-temperature Cu-Cu direct bonding technique is applied to a connection of the first trace and the second trace.