How to increase the clickable area of a tkinter checkbutton?

I understand how to size typical widgets like btn = tk.Button(root, width=10, height=10) etc.

I cannot figure out how to change the size of a checkbutton box.

chk=tk.Checkbutton(root, width=10, height=10) only changes the area surronding the box and associated text.

Using sticky=N+S+E+W in pack/grid calls does not stretch the checkbox out either.