The height advantage of the BGA-1 processor and the production advantage of a socket processor have been combined in the Micro-PGA1 processor.
The BGA processor is mounted on top of a small PCB with attached pins. The height of the mounted processor increases to ~3.5 mm plus 1.25mm for the pins.
Micro-PGA1 CPU top view
Micro-PGA1 CPU bottom view
When a processor is being soldered directly to the PCB, the notebook vendor loses flexibility to react to new processor prices. Notebooks are usually shipped from the notebook maker to the notebook vendor as a bare bone. A notebook bare bone comes without HDD, processor and only onboard RAM. When the CPU price changes while the notebook is on its way from the production site to the final kitting site, the customer requests a different specification. With the barebones that are in stock, the notebook vendor needs flexibility to order production with little stock risk due to processor price change.