From 098219d56c9bf8127ba45dc69739f7ebc494595c Mon Sep 17 00:00:00 2001
From: mrg <mrg@ucsc.edu>
Date: Thu, 11 Jun 2020 11:53:59 -0700
Subject: [PATCH] Add npc enclosure to poly contacts

---
 compiler/base/contact.py | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/compiler/base/contact.py b/compiler/base/contact.py
index 14dbf76e..cc1ca27a 100644
--- a/compiler/base/contact.py
+++ b/compiler/base/contact.py
@@ -7,7 +7,7 @@
 #
 import hierarchy_design
 import debug
-from tech import drc
+from tech import drc, layer
 import tech
 from vector import vector
 from sram_factory import factory
@@ -44,7 +44,8 @@ class contact(hierarchy_design.hierarchy_design):
             self.add_comment("well_type: {}\n".format(well_type))
 
         self.is_well_contact = implant_type == well_type
-        
+
+        # If we have a special tap layer, use it
         self.layer_stack = layer_stack
         self.dimensions = dimensions
 
@@ -196,17 +197,19 @@ class contact(hierarchy_design.hierarchy_design):
         if "npc" not in tech.layer:
             return
 
+        npc_enclose_poly = drc("npc_enclose_poly")
+        npc_enclose_offset = vector(npc_enclose_poly, npc_enclose_poly)
         # Only add for poly layers
         if self.first_layer_name == "poly":
             self.add_rect(layer="npc",
-                          offset=self.first_layer_position,
-                          width=self.first_layer_width,
-                          height=self.first_layer_height)
+                          offset=self.first_layer_position - npc_enclose_offset,
+                          width=self.first_layer_width + 2 * npc_enclose_poly,
+                          height=self.first_layer_height + 2 * npc_enclose_poly)
         elif self.second_layer_name == "poly":
             self.add_rect(layer="npc",
-                          offset=self.second_layer_position,
-                          width=self.second_layer_width,
-                          height=self.second_layer_height)
+                          offset=self.second_layer_position - npc_enclose_offset,
+                          width=self.second_layer_width + 2 * npc_enclose_poly,
+                          height=self.second_layer_height + 2 * npc_enclose_poly)
     
     def create_first_layer_enclosure(self):
         # this is if the first and second layers are different
@@ -218,7 +221,11 @@ class contact(hierarchy_design.hierarchy_design):
                                      self.first_layer_minwidth)
         self.first_layer_height = max(self.contact_array_height + 2 * self.first_layer_vertical_enclosure,
                                       self.first_layer_minwidth)
-        self.add_rect(layer=self.first_layer_name,
+        if self.is_well_contact and self.first_layer_name == "active" and "tap" in layer:
+            first_layer_name = "tap"
+        else:
+            first_layer_name = self.first_layer_name
+        self.add_rect(layer=first_layer_name,
                       offset=self.first_layer_position,
                       width=self.first_layer_width,
                       height=self.first_layer_height)