Method of manufacture of an integrated circuit package

1. A method of manufacturing an integrated circuit (“IC”) package comprising radio frequency (“RF”) components, the method comprising:

electrically connecting a printed circuit pattern on an external major surface of an IC assembly to an RF testing motherboard by bringing them together with an interposed adaptor layer, the adaptor layer comprising a double-sided printed circuit board (“PCB”) with conductive vias between its printed circuit layers;

RF testing the IC assembly using the RF testing motherboard, whilst RF tuning components of the IC assembly; and

separating the IC assembly and connecting its major surface to a solder ball grid array (“BGA”) which has substantially the same RF impedance as the adaptor at RF signal paths from the IC assembly to the BGA;

wherein the adaptor layer substantially simulates an impedance of the BGA at the RF wavebands over which the IC assembly operates.

2. A method according to claim 1 , comprising applying a predetermined normal pressure between the IC package, the adaptor layer and the RF testing motherboard.

3. A method according to claim 1 , wherein spacings between the vias in the adaptor layer correspond to spacings between balls of the BGA.

4. A method according to claim 1 , wherein the signal paths between the IC assembly and the BGA comprise coaxial signal paths consisting of a central signal path to one ball surrounded by plural grounded balls of the BGA.

5. A method according to claim 4 , wherein the impedances of these coaxial signal paths are in the range of 40Ω to 60Ω.

6. A method according to claim 5 , wherein the impedances are substantially 50Ω.

7. A method according to claim 1 , wherein the IC assembly comprises a microwave circulator and the method comprises RF tuning ports of the microwave circulator before connection to the BGA.