US 12,404,170 B2
Method for producing a bonding pad for a micromechanical sensor element
Andreas Prinzen, Reutlingen (DE); Christof Schwenk, Stuttgart (DE); Frank Reichenbach, Wannweil (DE); Friedjof Heuck, Stuttgart (DE); Heiko Stahl, Reutlingen (DE); and Nicolas Schorr, Reutlingen (DE)
Assigned to ROBERT BOSCH GMBH, Stuttgart (DE)
Filed by Robert Bosch GmbH, Stuttgart (DE)
Filed on Jan. 9, 2023, as Appl. No. 18/151,631.
Claims priority of application No. 10 2022 200 343.8 (DE), filed on Jan. 13, 2022.
Prior Publication US 2023/0219808 A1, Jul. 13, 2023
Int. Cl. B81C 1/00 (2006.01)
CPC B81C 1/00571 (2013.01) [B81C 2201/0132 (2013.01); B81C 2201/0198 (2013.01); B81C 2203/0109 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A method for producing a bonding pad for a micromechanical sensor element, comprising the following steps:
supplying a layered structure having a micromechanical functional layer on a top face of the layered structure;
depositing a first metal layer of a first thickness onto a top face of the functional layer, and depositing a second metal layer of a second thickness onto the first metal layer, wherein either only the first layer or only the second layer is formed in a border region extending around a bonding pad region;
covering a protective layer over a top face of the second metal layer in the bonding pad region and over the first or second metal layer in an inner peripheral portion of the border region, the inner peripheral portion adjoining the bonding pad region;
etching the first or second layer at least in an outer peripheral portion of the border region down to the top face of the functional layer to provide an exposed outer portion of the border region, wherein the inner peripheral portion of the border region remains covered with the first layer;
removing the protective layer;
carrying out an etching process in the exposed outer portion of the border region starting from the top face of the layered structure, wherein a bonding pad region having the bonding pad is released from a surrounding bonding frame region, wherein the second layer is used as an etching mask; and
removing the first or second metal layer from the inner peripheral portion of the border region using an unmasked etching process so as to obtain a bonding pad having a peripheral edge region, wherein the edge region is inwardly set back from a peripheral side face of the bonding pad region of the functional layer.