The 3 companies mentioned b4 can consider as best in Ipoh liao
Unisem ---> around simpang pulai
Carsem ---> Jelapang and the one near Airport (forget wat name)
FInisar ---> Near jln kuala kangsar

For me, Finisar is the best, MNC mah......They r more concentrate in Fibre optics.
Carsem, IC manufacturing.
Unisem, dunno.....