Control of under-fill using a film during fabrication for a dual-sided ball grid array package

Disclosed herein are methods of fabricating a packaged radio-frequency (RF) device. The disclosed methods use a film during fabrication to control the distribution of an under-fill material between one or more components and a packaging substrate. The method includes mounting components to a first side of a packaging substrate and applying a film to a second side of a packaging substrate. The method also includes mounting a lower component to the second side of the packaging substrate and under-filling the lower component mounted on the second side of the packaging substrate with an under-filling agent. The method also includes removing the film on the second side of the packaging substrate and mounting solder balls to the second side of the packaging substrate after removal of the film.