[MCU] Microcontroller Packaging

QFN : Quad Flat No Leads:

These connect IC's to PCB's without through-holes.
The figure shows with lead frame and wire bonding. Flat no-lead packages include an exposed thermal pad to improve heat transfer out of the IC (into the PCB).  Hand soldering is not possible with this package

QFP: Quad Flat Package

A surface mounted IC, pins extending for all the 4 sides.  Socketing such packages is rare and through-hole mounting is not possible.

LQFP: Low Profile Quad Flat Package (1.4mm)

TQFP: Thin Quad Flat Package (1.0 mm) 

Has shorter leads than the LQFP. To be used in a space constrained designs.
Helps in solving increased board density.

References

https://en.wikipedia.org/wiki/Quad_Flat_No-leads_package
https://en.wikipedia.org/wiki/Quad_Flat_Package