本公众号【读芯树:duxinshu_PD】主要介绍数字集成电路物理设计相关知识,才疏学浅,如有错误,欢迎指正交流学习。
这是集成电路物理设计的第一个系列【physical cell】的第一篇文章,也是本公众号的第一篇文章,从boundary cell说起:
1,什么是boundary cell?
2,为什么需要insert boundary cell? 在芯片制造的过程中,最边界的standard cell最容易受到损伤,为减少standard cell的制造过程中的损伤,需要在边界放置boundary cell,boundary cell有dummy poly gate,当制造过程中的损伤发生在边界时,boundary cell的损伤不会影响正常standard cell的功能。 如果没有在边界放置boundary cell, 可能会对芯片的功能造成不可逆的损伤。 在well和implant 层之间不能有gap,否则会有drc,boundary cell保证了well和implant 层之间没有gap。 boundary cell的poly extension保证了standard cell的source/drain不会出现在边界。 boundary cell放置在row的边界同时保证了边界的well tie的需求。
3,boundary cell的layout是什么样的?
boundary cell没有logic pin,只有VDD/GND的连接; boundary cell在最左或者右侧扩展NWELL来减小well proximity effects (WPE 见5)。 boundary cell有dummy poly用于保护standard cell 的gate。 boundary cell的poly layer会被切断 (Poly Cut layer)
4,如何在floor plan阶段insert boundary cell?
>set_boundary_cell_rules \ -top_boundary_cells 'BOUNDARYPROW* \ -bottom_boundary_cells 'BOUNDARYPROW* \ -left_boundary_cell 'BOUNDARYLEFT*' \ -right_boundary_cell 'BOUNDARYRIGHT*' \ -top_right_outside_corner_cell 'BOUNDARYPCORNE*' \ -bottom_right_outside_corner_cell 'BOUNDARYPCORNER*' \ -top_left_outside_corner_cell 'BOUNDARYPCORNER*' \ -bottom_left_outside_corner_cell 'BOUNDARYPCORNER*' \ -top_right_inside_corner_cells 'BOUNDARYPINCORNER*' \ -bottom_right_inside_corner_cells 'BOUNDARYPINCORNER*' \ -top_left_inside_corner_cells 'BOUNDARYPINCORNER* \ -bottom_left_inside_corner_cells 'BOUNDARYPINCORNER*' \ -top_left_inside_horizontal_abutment_cells 'BOUNDARYPROWLGAP*' \ -bottom_left_inside_horizontal_abutment_cells 'BOUNDARYPROWLGAP*' \ -top_right_inside_horizontal_abutment_cells 'BOUNDARYPROWRGAP*' \ -bottom_right_inside_horizontal_abutment_cells 'BOUNDARYPROWRGAP*'\ -mirror_left_inside_corner_cell \ -mirror_left_outside_corner_cell \ -segment_parity {horizontal_odd vertical_even} \ -min_vertical_jog 0.042 \ -min_horizontal_jog 0.612 \ -min_vertical_jog 0.042 \ -min_horizontal_jog 0.612 \ -min_vertical_separation 0.21 \ -min_horizontal_separation 2.397-rightEdge BOUNDARYLEFT* \ -leftEdge BOUNDARYRIGHT*\ -leftTopCorner BOUNDARYPCORNER*\ -leftBottomCorner BOUNDARYPCORNER* \ -rightTopCorner BOUNDARYPCORNER*\ -rightBottomCorner BOUNDARYPCORNER* \ -topEdge {BOUNDARYPROW8* BOUNDARYPROW4*BOUNDARYPROW2* BOUNDARYPROW1*}-bottomEdge {BOUNDARYPROW8* BOUNDARYPROW4* BOUNDARYPROW2* BOUNDARYPROW1*} \-rightTopEdge BOUNDARYPINCORNER* \ -rightBottomEdge BOUNDARYPINCORNER* \ -leftTopEdge BOUNDARYPINCORNER* \ -leftBottomEdge BOUNDARYPINCORNER* \ -rightTopEdgeNeighbor BOUNDARYPROWRGAP*\ -rightBottomEdgeNeighbor BOUNDARYPROWRGAP*\ -leftTopEdgeNeighbor BOUNDARYPROWLGAP*\ -leftBottomEdgeNeighbor BOUNDARYPROWLGAP*\ >addEndCap >verifyEndCap -report endcap.rpt 5, 什么是阱临近效应(WPE: Well Proximity Effect) 6,参考文献
1,Fusion Compiler/ IC Compiler user guide
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