Is integrated circuit packaging copyrighted/patented?
Most of the common, industry-standard IC package types are covered by JEDEC standards. If there is an associated JEDEC standard code for the package, then the patent is held by a manufacturer who is a JEDEC member, and there are available license terms for the applicable patents.

More innovative packages might be covered by other patents which might not be available. If you want to make a plastic DIP 16 packages lead frame, that’s a common JEDEC standard part code MS-001BE. If you want to copy a unique device package that you found when for example you ripped open your iPhone, that may violate someone’s patent...

Sticking with standard package types makes it easier to test (because you can use standard ATE test handler fixtures), easier to ship (because you don’t need to develop your own tubes boxes bags etc), and easier for the end customer to use (existing Eagle CAD footprints).

Check the data sheet for any common part, look for the package drawing, and you will find many of them reference JEDEC standard package codes.