diff --git a/src/dbSta/include/db_sta/dbNetwork.hh b/src/dbSta/include/db_sta/dbNetwork.hh
index 8b85f43d03e..bd90306da24 100644
--- a/src/dbSta/include/db_sta/dbNetwork.hh
+++ b/src/dbSta/include/db_sta/dbNetwork.hh
@@ -128,6 +128,7 @@ class dbNetwork : public ConcreteNetwork
                dbBTerm*& bterm) const;
   dbBTerm* staToDb(const Term* term) const;
   dbMaster* staToDb(const Cell* cell) const;
+  void staToDb(const Cell* cell, dbMaster*& master, dbModule*& module) const;
   dbMaster* staToDb(const LibertyCell* cell) const;
   dbMTerm* staToDb(const Port* port) const;
   dbMTerm* staToDb(const LibertyPort* port) const;
diff --git a/src/dbSta/src/dbNetwork.cc b/src/dbSta/src/dbNetwork.cc
index b59594209fb..0e6a5acec4f 100644
--- a/src/dbSta/src/dbNetwork.cc
+++ b/src/dbSta/src/dbNetwork.cc
@@ -115,6 +115,11 @@ Library* DbLibraryIterator1::next()
   return reinterpret_cast<Library*>(iter_->next());
 }
 
+//
+// check the leaves accessible from the network
+// match those accessible from block.
+//
+
 ////////////////////////////////////////////////////////////////
 
 class DbInstanceChildIterator : public InstanceChildIterator
@@ -552,7 +557,17 @@ Instance* dbNetwork::parent(const Instance* instance) const
 
 bool dbNetwork::isLeaf(const Instance* instance) const
 {
-  return instance != top_instance_;
+  if (instance == top_instance_) {
+    return false;
+  }
+  dbMaster* db_master;
+  dbModule* db_module;
+  Cell* cur_cell = cell(instance);
+  staToDb(cur_cell, db_master, db_module);
+  if (db_module) {
+    return false;
+  }
+  return true;
 }
 
 Instance* dbNetwork::findInstance(const char* path_name) const
@@ -1451,6 +1466,24 @@ dbBTerm* dbNetwork::staToDb(const Term* term) const
   return reinterpret_cast<dbBTerm*>(const_cast<Term*>(term));
 }
 
+void dbNetwork::staToDb(const Cell* cell,
+                        dbMaster*& master,
+                        dbModule*& module) const
+{
+  module = nullptr;
+  master = nullptr;
+  if (findLibertyCell(name(cell))) {
+    master = reinterpret_cast<dbMaster*>(const_cast<Cell*>(cell));
+  } else {
+    if (block_) {
+      if (block_->findModule(name(cell)))
+        module = reinterpret_cast<dbModule*>(const_cast<Cell*>(cell));
+      else
+        master = reinterpret_cast<dbMaster*>(const_cast<Cell*>(cell));
+    }
+  }
+}
+
 dbMaster* dbNetwork::staToDb(const Cell* cell) const
 {
   const ConcreteCell* ccell = reinterpret_cast<const ConcreteCell*>(cell);