请教encounter中post-mask eco遇到的问题

yminic

最初的设计，加入spare cell是采用　create sparemoudle　的方式添加的spare cell

dig.eco.v中只改了一个地方，只添加了一个单元
DEL01BWP7T ECO_cell_1 (//ECO
   .I(n600),//ECO
   .Z(ECO_net_1)//ECO
   );//ECO

//   AOI211D0BWP7T U35 (.A1(n600), //ECO
   AOI211D0BWP7T U35 (.A1(ECO_net_1),
        .A2(n14),
        .B(n42),
        .C(n5),
        .ZN(n8));

而且相应的spare cell 也有这个单元：
　DEL01BWP7T DEL01BWP7T_spr_gate1291 (.I(FE_OFN883_tie_hi_net0));
   DEL01BWP7T DEL01BWP7T_spr_gate1290 (.I(FE_OFN883_tie_hi_net0));
   DEL01BWP7T DEL01BWP7T_spr_gate1289 (.I(FE_OFN883_tie_hi_net0));
   DEL01BWP7T DEL01BWP7T_spr_gate1288 (.I(FE_OFN883_tie_hi_net0));
   DEL02BWP7T DEL02BWP7T_spr_gate1287 (.I(FE_OFN883_tie_hi_net0));
   DEL02BWP7T DEL02BWP7T_spr_gate1286 (.I(FE_OFN883_tie_hi_net0));
   DFCND2BWP7T DFCND2BWP7T_spr_gate1285 (.D(FE_OFN882_tie_lo_net0),

在做post-mask eco时，使用的命令行如下：
coDesign -postMask -modifyOnlyLayers 1:5 -spareCells spr* dig.enc.dat dig dig.eco.v

运行过程中，总是报错：
**ERROR: (SOCSYC-2100):    Instance U_DIG/U_MEDIAN/ECO_cell_1 added but couldn't find spare cell for it.

但可以确定，dig.eco.v网表中新增加的ECO_cell_1的确是sparemodule中存在的单元。但不知道为何就是找不到相应的spare cell去替换。
请有经验的大侠们帮忙分析和解答一下，我的flow中是哪里出了问题？

在eco的过程中，看起来也找到了这个spare cell的：
Specifying instance [spr_15/DEL01BWP7T_spr_gate1291] as spare gate.
Specifying instance [spr_15/DEL01BWP7T_spr_gate1290] as spare gate.
Specifying instance [spr_15/DEL01BWP7T_spr_gate1289] as spare gate.
Specifying instance [spr_15/DEL01BWP7T_spr_gate1288] as spare gate.
Specifying instance [spr_15/DEL02BWP7T_spr_gate1287] as spare gate.
Specifying instance [spr_15/DEL02BWP7T_spr_gate1286] as spare gate.
Specifying instance [spr_15/DFCND2BWP7T_spr_gate1285] as spare gate.
Specifying instance [spr_15/DFCND2BWP7T_spr_gate1284] as spare gate.
....
Specifying instance [spr_1/AOI222D2BWP7T_spr_gate2] as spare gate.
Specifying instance [spr_1/TIEHBWP7T_spr_gate1] as spare gate.
Specifying instance [spr_1/TIELBWP7T_spr_gate0] as spare gate.
Specified 1397 instances as spare gate.

**ERROR: (SOCSYC-2100):    Instance U_DIG/U_MEDIAN/ECO_cell_1 added but couldn't find spare cell for it.
**WARN: (SOCSYT-6782):  Design has no tie cells so all tie connections will be connected to ground.

因为这里报错,所以后续ecoroute也会报错
#ERROR (NRDB-160) INSTANCE U_DIG/U_MEDIAN/ECO_cell_1 is unplaced. All instances must be placed before routing. Refer to Cadence placer or checkPlace for more information.

请大家指点一下,这种情况是哪里做得不正确!
多谢!