回复 2# bsbs525
谢谢。本来我以为EndCap就是在VDD和GND之间的电容,起稳压作用,但下面的段落又不是这样说,这来自ARM SAGE standard cell data book。我尤其不清楚Twin-well, Triple-well和EndCap的关系,可否解释一下?
WELLANTENNA Cell
This process requires that, for any standard cell row with a device in it, the N-well must be tied down to the substrate
and triple-wells must be tied to the enclosing N-well. Any connection between the wells is usually sufficient. In a
triple-well design, the connection will happen automatically when you place the ENDCAP cells at the ends of the
standard cell rows. In triple-well and twin-well designs, any CMOS standard cell (such as an inverter) placed in a
standard cell row will also make the connection; however, in a twin-well design, if a pair of standard cell rows, sharing
an N-well, or a single standard cell row is populated by nothing but FILL cells and/or ANTENNA cells and at least
one FILLCAP cell, then the associated N-well will be in violation of the well antenna rule. In this scenario, the N-well
must be tied down to the substrate by inserting a WELLANTENNA cell into the standard cell row in violation. |