how to design a thremal enhance package LQFP80?

[kimjin]

i want to design a LQFP80 thremal enhance pack, it has a 1x1(cm2) pad under the package for thremal enhance. how to design the package, and the what's the relation between the symbol's pin and package's pin?
and how to place a shape without mask solder?
thank you.

 

[kimjin]

how to place a copper plane without solder mask on top layer?

 

[gorkin]

Well brother, we can answer You, but fundamental "detail" is needed like: What EDA Your use? Different EDA has different methods for implemantation of cooper planes... and layers names...

 

[kimjin]

i use allegro,

 

[centiago]

kimjin,
All you can define when you are creating padstack.

There is no hard & fast rule for creating antipad/thermalpad/mask. Standard companies have their own rules (it varies from company to company).
for generic information pls reffer to IPC standards
GoodLuck