license with patent grants appropriate for specifications?

[Bob Scheifler]

I'm looking for a license to use for specifications rather than code,
that contains patent grants that are appropriate for specifications.
In particular, the distinguishing characteristic in my mind is
making grants for patents that would necessarily be infringed by
"implementations of the Work", versus making grants for patents
that are infringed by the Work itself. (On the assumption that a
mere specification cannot infringe patents.)

Is anyone aware of an open source or free/open documentation license
that does this or could reasonably be interpreted to do this?

- Bob