TO THE FAB SHOPS;

THE COMPANY I'VE BEEN WORKING AT HAS BEEN DESIGNING WITH .007 WIDE TRACES AND
.004 SPACING FOR YEARS. THIS CAN'T BE THAT MUCH DIFFERENT THAN THE REST OF THE
COUNTRY. AND PERHAPS THIS IS PUSHING THE FAB SHOPS TO THEIR LIMITS.

I THOUGHT YOU WERE DOING A GOOD JOB OF KEEPING UP WITH OUR DESIGNS. BUT NOW
I HEAR THAT YOUR YIELDS ARE DECREASING, OR PERHAPS THEY HAVE BEEN FOR YEARS, 
AND ENOUGH IS ENOUGH. IT LOOKS AS THOUGH FINE-LINE TECHNOLOGY HAS EVOLVED TO
IT'S PRACTICAL LIMITS FOR NOW. MAYBE THE INDUSTRY SHOULD PAUSE FOR NOW UNTILL
NEW PROCESSES CAN BE INSTALLED TO ALLOW FOR EVER INCREASING DENSITY.

FAB SHOPS HAVE ALWAYS MADE INTERNAL ADJUSTMENTS TO OUR GERBER DATA, TO TRY AND
COMPENSATE FOR THEIR OWN ETCHING VARIABLES. I KNOW FOR A FACT THAT SOME SHOPS
ADD .001-.0015 TO ALL APERTURES WHEN PHOTOPLOTING, JUST TO TRY AND MEET OUR
PWB SPECS. BUT, BY DOING THIS, OUR .004" SPACINGS ARE GREATLY REDUCED. THIS
ALONE CAN REDUCE FAB YIELDS. THAT'S NOT THE DESIGNERS FAULT, JUST A FACT.

DO FAB SHOPS WANT TO PULL PADS JUST TO COMPENSATE FOR THESE KIND OF ETCHING
VARIABLES? OR CAN WE EXPECT EVEN FURTHER REDUCTIONS IN TRACE WIDTHS/GAPS ?

DON'T GET ME WRONG, IF BOARDS WITH INTERNAL PADS REMOVED ARE JUST AS RELIABLE
AS FULLY PADDED BOARDS, THEN IT'S FINE WITH ME. SOME CAD SYSTEMS HAVE HAD THE
CAPABILITY TO REMOVE UNUSED PADS WHEN EXTRACTING GERBERS FOR A LONG TIME.

MY HAT'S OFF TO YOU GUY'S FOR KEEPING UP WITH THE STATE OF FINE-LINE BOARDS.
AND WE'LL KEEP MAKING IT HARDER UNTIL YOU SQUEAL LOUDER THAN WE DO.