Semiconductor Packages, Systems, and Methods of Formation Thereof

A semiconductor package comprising:

• a current rail having contact pad regions and a magnetic field generating portion;
• a semiconductor chip disposed over the current rail, the semiconductor chip comprising a magnetic field sensor, the magnetic field sensor being proximate the current rail;
• a package body securing the current rail and the semiconductor chip, wherein portions of a back surface of the current rail are exposed at a bottom surface of the package body;
• and
• an anti-solder layer covering first parts of the exposed portions of the back surface of the current rail.

A system comprising:

• a circuit board having solder pads;
• and
• a semiconductor package coupled to the circuit board through the solder pads, wherein the semiconductor package comprises:
• a current rail having contact pad regions,
• a semiconductor chip disposed over the current rail, the semiconductor chip comprising a magnetic field sensor, the magnetic field sensor being proximate the current rail,
• a package body securing the current rail and the semiconductor chip, wherein portions of a back surface of the current rail are exposed at a bottom surface of the package body facing the circuit board, and
• an anti-solder layer covering parts of the exposed portions of the back surface of the current rail, wherein the solder pads of the circuit board are disposed under and coupled to the contact pad regions.

A method of forming a semiconductor package, the method comprising:

• etching a magnetic field generating portion in a lead frame substrate;
• etching a plurality of grooves in the lead frame substrate, wherein the plurality of grooves are proximate the magnetic field generating portion, wherein the plurality of grooves has a second thickness less than a first thickness of the lead frame substrate, wherein, in a plan view, the magnetic field generating portion is disposed between a first groove of the plurality of grooves and a second groove of the plurality of grooves;
• and
• attaching a semiconductor chip over the lead frame substrate, the semiconductor chip being proximate the magnetic field generating portion.

A method of forming a semiconductor package, the method comprising:

• providing a lead frame substrate having a magnetic field generating portion;
• attaching a semiconductor chip over the magnetic field generating portion, the semiconductor chip comprising a magnetic field sensor disposed proximate the magnetic field generating portion;
• forming a package body securing the lead frame substrate and the semiconductor chip, wherein portions of a back surface of the lead frame substrate are exposed at a bottom surface of the package body;
• and
• forming an anti-solder layer under parts of the exposed portions of the back surface of the lead frame substrate.