Re: copyright expiration as a spur to creativity

Bruce Hayden <bhayden[_at_]ieee.org> wrote:
>
> Terry Carroll <carroll[_at_]tjc.com> wrote:
> >
> > On Fri, 18 Sep 1998, Karsten M. Self <kmself[_at_]ix.netcom.com> wrote:
> > >
> > > Semiconductor chip copyrights extend for 10 years
> >
> > Mask work protection extends for 10 years, but onlyif the mask work
> > is registered. If an application to register isnot filed within the
> > first two years of commercial exploitation, the protection terminates.
>

[snip]
> Another problem is that these ICs tend to require a number of
> levels of interconnect. For exmaple, you may have two local,
> and four general layers of metal on top of your active elements.
> These must be lined up exactly so that they can be connected.
> Again, shrinkage is critical - if something is not long
> enough or wide enough, you don't connect.
>
> The result is that at least with today's technology, even
> using an electron microscope scan of such an IC, it would
> be extremely hard, if not impossible, to get an operating
> chip by copying the original IC.

Bruce,

  The commercial life of an integrated circuit (defined by the revision of the mask set, each revision creates a "new" circuit) is rarely two years, making the protection seldom used for that reason alone (why pay money if there is no problem, and if the probblem occurs, then file).

  The problem is considerably more complex than you represented (a CMOS circuit may have 20+ layers on it, not counting the epi layers that prepare the wafer to accept the circuit). That said, a good failure analysis lab can remove the layers from a circuit and expose for photographing (and subsequent mask making) each layer. An analysis of a failure involves exactly this type of process, in order to determine the cause of a failure in a particular IC. Most IC fabrication facilities have a failure analysis lab, so they can figure out why yields are not as expected.

  When Digital Equipment was manufacturing VAX circuits, they placed the text "When you care to steal the very best" in Russian Crylic on one of the layers, so that the message could be read by those DEC expected would be stealing the design by reverse engineering it...

  The far greater vulnerability is to the theft of a set of masks for a circuit. The masks for a given design fit into a briefcase, and this is by far the easiest way to "steal" a design. These masks are often made on glass, which may break as a result of handling, and may be discarded. Enlightened chip manufacturers take care when they discard such defective masks, so that they do not fall into the hands of spys, domestic or foreign.

Thomas Workman
<tworkman[_at_]erols.com> Received on Fri Sep 25 1998 - 14:59:11 GMT