vhdl-copyright-string

vhdl-copyright-string is a variable defined in `vhdl-mode.el'.
Its value is

"-------------------------------------------------------------------------------\n-- Copyright (c)  \n"

Documentation:
Copyright string to insert in file header.
Can be multi-line string (type `C-j' for newline) and contain other file
header keywords (see option `vhdl-file-header').

You can customize this variable.