High frequency transition matching in an electronic package for millimeter wave semiconductor dies

A method of high frequency chip to circuit board transition, said method comprising:

• providing a semiconductor chip comprising a ground plane, a high frequency microstrip electrically connected to a signal receiver or signal transmitter, a first high frequency pad electrically connected to said high frequency microstrip, and a plurality of first ground pads;
• providing a high frequency circuit board constructed from a dielectric material, said high frequency circuit board comprising a ground plane, a second high frequency pad and a plurality of second ground pads;
• placing at least one high frequency bump to electrically connect said first high frequency pad and said second high frequency pad to convey a high frequency signal;
• placing a plurality of bumps operative to electrically connect said plurality of first ground pads with said plurality of second ground pads so as to connect the around planes on said semiconductor chip and said high frequency circuit board;
• modifying a portion of said ground plane of said semiconductor chip above said first high frequency pad so as to improve impedance matching of the said at least one high frequency bump transition, said modified portion increasing a distance between said semiconductor chip ground plane and said first high frequency pad so that a series inductance of said high frequency bump is decreased by increased deviation of a ground current relative to a signal current;
• and
• wherein said high frequency microstrip and said first high frequency pad are both disposed on a lower surface of said semiconductor chip facing said high frequency circuit board.

A high frequency chip to circuit board transition, comprising:

• a semiconductor chip comprising a ground plane, a high frequency microstrip electrically connected to a signal receiver or signal transmitter, a first high frequency pad electrically connected to said high frequency microstrip, and a plurality of first ground pads;
• a high frequency circuit board constructed from a dielectric material, said high frequency circuit board comprising a ground plane, a second high frequency pad and a plurality of second ground pads;
• a high frequency bump electrically connecting said first high frequency pad and said second high frequency pad to convey a high frequency signal;
• a plurality of bumps operative to electrically connect said plurality of first ground pads with said plurality of second ground pads so as to connect the ground planes on said semiconductor chip and said high frequency circuit board;
• wherein said high frequency circuit board comprises a high frequency ground plane substantially encircling said second high frequency pad;
• wherein a portion of said ground plane of said semiconductor chip above said first high frequency pad is removed, said removed portion increasing a distance between said semiconductor chip ground plane and said first high frequency pad so that a series inductance of said high frequency bump is decreased by increased deviation of a ground current relative to a signal current;
• and
• wherein said high frequency microstrip and said first high frequency pad are both disposed on a lower surface of said semiconductor chip facing said high frequency circuit board.