Device having conductive substrate via with catch-pad etch-stop

US8410580B2 · kind B2 · utility

Assignee

• Freeescale Semiconductor, Inc. · US

Inventors

• Darrell G. Hill · Tempe, US
• Bruce M. Green · Gilbert, US

Key dates

• Filing date: Jan 12, 2011
• Grant date: Apr 2, 2013
• Expiry date: May 7, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/12044
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

An electronic device (50) having a conductive substrate via (70) extending between a conductor (39) on a rear face (22) and a conductor (58) over the front surface (23) of the substrate (21) includes a multi-layered etch-stop (56, 56-2) beneath the front surface conductor (58). The etch-stop (56, 56-2) permits use of a single etchant to penetrate both the substrate (21) and any overlying semiconductor (44) and/or dielectric (34) without attacking the overlying front surface conductor (58). This is especially important when the semiconductor (44) and dielectric (34) are so thin as to preclude changing etchants when these regions are reached during etching. The etch-stop (56) is preferably a stack (63, 73) of N≧2 pairs (62-i) of sub-layers (62-i1, 62-i2) in either order, where a first sub-layer (62-i1) comprises stress relieving and/or adhesion promoting material (e.g., Ti), and the second sub-layer (62-i2) comprises etch resistant material (e.g., Ni). In a further embodiment, where the device (50) includes field effect transistors (52) having feedback sensitive control gates (30), the etch-stop material (56) is advantageously used to form gate shields (76).