Test apparatus and method for testing a semiconductor device

An apparatus comprising:

• a semiconductor device comprising an integrated circuit and a plurality of external radiating elements at a surface of the device, the radiating elements including at least one transmit element and at least one receive element;
• and
• a test apparatus for testing the semiconductor device, the test apparatus comprising:
• a plunger comprising:
• a dielectric portion having a surface for placing against said surface of the device;
• and
• at least one waveguide, wherein each waveguide extends through the plunger for routing electromagnetic radiation transmitted by one of said transmit elements of the device to one of the receive elements of the device, wherein each waveguide comprises a plurality of waveguide openings for coupling electromagnetically to corresponding radiating elements of the plurality of radiating elements located at the surface of the device, wherein the at least one waveguide is configured to route electromagnetic radiation transmitted by one of said transmit elements of the device to a plurality of receive elements of the device, the at least a one waveguide comprising a first branch for conveying electromagnetic radiation transmitted by said transmit element and at least two further branches coupled to the first branch for route said electromagnetic radiation to said plurality of receive elements,
• wherein the dielectric portion is configured to provide a matched interface for said electromagnetic coupling of the plurality of waveguide openings of the plunger to the plurality of radiating elements of the device.

A method of testing a semiconductor device, the method comprising:

• providing a semiconductor device comprising an integrated circuit and a plurality of external radiating elements located at a surface of the device, the external radiating elements including at least one transmit element and at least one receive element;
• providing a test apparatus comprising:
• a plunger comprising:
• a dielectric portion having a surface for placing against said surface of the device;
• and
• at least one waveguide, wherein each waveguide extends through the plunger for routing electromagnetic radiation transmitted by one of said transmit elements of the device to one of the receive elements of the device, wherein each waveguide comprises a plurality of waveguide openings for coupling electromagnetically to corresponding radiating elements of the plurality of radiating elements located at the surface of the device, wherein the at least one waveguide is configured to route electromagnetic radiation transmitted by one of said transmit elements of the device to a plurality of receive elements of the device, the at least a one waveguide comprising a first branch for conveying electromagnetic radiation transmitted by said transmit element and at least two further branches coupled to the first branch for route said electromagnetic radiation to said plurality of receive elements,
• wherein the dielectric portion is configured to provide a matched interface for said electromagnetic coupling of the plurality of waveguide openings of the plunger to the plurality of external radiating elements of the device;
• placing said surface of the dielectric portion of the plunger against said surface of the device;
• and
• transmitting electromagnetic radiation from at least one said transmit element to at least one said receive element via at least one waveguide of the plunger.