Millimeter wave wafer level chip scale packaging (wlcsp) device and related method

A wafer level chip scale package (WLCSP) structure comprising:

• a printed circuit board (PCB) trace connection including at least one PCB ground connection connected with a PCB ground plane;
• a set of ground solder balls each contacting the printed circuit board trace connection;
• a set of chip pads contacting each of the ground solder balls in the set of ground solder balls;
• a chip ground plane connecting the set of chip pads;
• and
• a signal interconnect interposed between two of the set of ground solder balls, the signal interconnect including:
• a signal trace connection electrically isolated from the PCB ground plane,
• wherein the signal trace connection electrically isolated from the PCB ground plane includes a conductive strip which forms a microstrip line with the PCB ground plane for carrying a signal;
• a signal ball contacting the signal trace connection;
• a chip pad contacting the signal ball;
• and
• a signal trace connection on a chip contacting the chip pad,
• wherein a diameter of the signal ball controls an amount of signal loss in the WLCSP structure,
• wherein the chip ground plane includes an opening above the signal chip pad, and the PCB ground plane includes an opening underneath the signal solder ball for performance tuning,
• wherein the chip ground plane forms a semi annular shape having the opening above the signal chip pad, the opening above the signal chip pad located in a region interposed between the two of the set of ground solder balls.