Ultrathin magnetoresistive sensor package

Claim 1

A magnetic field sensor assembly comprising: a flexible circuit board having a first major surface with a predetermined area for receiving at least one semiconductor magnetic field sensor chip, and also having an opposite major surface and a given thickness; at least one semiconductor magnetic field sensor chip affixed to said predetermined area of said first major surface of said flexible circuit board; a magnetic field means disposed against said magnetic field sensor chip; an electrically nonconductive supporting body enclosing said semiconductor magnetic field sensor chip and said magnetic field means on said predetermined area of said first major surface of said flexible circuit board but leaving said opposite major surface exposed opposite said predetermined area, whereby said body supports said flexible circuit board but leaves said semiconductor magnetic said sensor chip covered in said predetermined area by only said thickness of said flexible circuit board; locating means on said flexible circuit board for precisely positioning said circuit board on said body, said locating means being in predetermined identified dispositional relationship with respect to said at least one affixed semiconductor magnetic field sensor chip, whereby precise positioning of said circuit board on said body by said locating means concurrently precisely positions said at least one affixed semiconductor magnetic field sensor chip on said body; an extension of said flexible circuit board from said predetermined area to a second area outside of said body; a circuit pattern on said first major surface, including portions of said predetermined area proximate said semiconductor magnetic field sensor chip for interconnection therewith; means for interconnecting said semiconductor magnetic field sensor chip with said circuit pattern portions; electrical conductors in said circuit pattern leading away from said chip-proximate portions to said second area of said flexible circuit board outside of said body; and means connected to said electrical conductors in said second area for receiving an output signal from said semiconductor magnetic field sensor; effective to provide a semiconductor magnetic field sensing chip on a flexible circuit board in precisely known disposition with respect to a supporting body, and to permit a reduced effective air gap between said chip and an exciter by providing a reduced packaging thickness covering said chip.