File 介绍——SPEF File

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这是集成电路物理设计的第三个系列【File】的第四篇文章，本篇文章主要讲解SPEF file相关内容：

1，什么是SPEF fille?

• SPEF = standard parasitic exchange format

• 每一条net都会存在电阻和寄生电容，这些信息保存在SPEF文件中。

• SPEF文件是一种标准的中间文件，可以应用于不同的EDA工具。

• 在STA分析时，需要SPEF文件进行cell/net delay的计算。
  

• 在IR分析时，需要SPEF文件得到net的RC信息。

• SPEF文件一般是通过starrc或者qrc得到。
  

2，SPEF File介绍

• SPEF File主要包含4部分：

1. Header Section

   SPEF Version
   Design Name
   Date of generation
   Tool Vendor Name
   Parasitic Extraction Tool Name
   Version of Tool
   Design Flow
   Dividerr
   Hierarchy Delimiter
   Bus Delimiter
   Unit

   
   

2. Name Map Section

   关键字：“*NAME_MAP”
   这种映射关系可以大大减小文件的大小。
   映射的net的名字从“*”开始

   
   

3. Top Level Port Section

   关键字：“*PORT”
   port的方向有I: input, O: output, B: inout
   

   
   

4. Parasitic description Section

   关键字：“*D_NET”
   *D_NET: the net mapping name, sum of all capacitance。
   *CONN section: net的连接关系
   *I: internal pins [*I <pin name> <direction> *C <xy coordinate> <loading or driving information>] (*C: gives the xy coordinate of pin in layout, *L: gives the load capacitance for an input pin, *D: gives the driving cell type for an output pin)。
   *CAP section：net上所有的电容信息，主要包括两部分：对地电容和耦合电容。(capacitor lumped to ground包括三部分：an identifying number, a node name，the capacitance value of the node；coupling capacitor包括四部分：an identifying number, two nodes name, the capacitance value between the node。)
   *RES section：net上所有的电阻信息。(resistor包括四部分：an identifying numbers, two nodes name, the value of resistance between two nodes。) 
   *END：net结束关键字

   
   

3，SPF/SPEF/DSPF/RSPF的区别

• SPF = standard parasitic format （a Cadence Design System standard for defining netlist parasitic）

• SPEF = standard parasitic exchange format (an Open Verilog Initiative and IEEE format)

• DSPF = detailed standard parasitic format (detailed network of RC parasitic)

  
  

• RSPF = reduced standard parasitic format (each net as an RC 'PI' model)

• SBPF = synopsys binary parasitic format (parasitic data converted to this format occipies less disk space and read much faster)

4，SPEF Flow

• StarRC Flow:

  >TOP_DEF_FILE: ./design.def
  >LEF_FILE: ./tech.lef
  >LEF_FILE: ./cell.lef
  >MAPPING_FILE ./starrc.map
  >NETLIST_FILE: ./design.spef.gz
  >NETLIST_FORMAT: SPEF
  >NETLIST_COMPRESS_COMMAND: gzip -q -f
  >DPT: YES
  >EXTRACT_VIA_CAPS: YES
  >BUS_BIT: []
  >HIERARCHICAL_SEPARATOR: /
  >NETS: *
  >METAL_FILL_GDS_FILE: ./design.dummy_metal.gds.gz
  >MMETAL_FILL_GDS_BLOCK: DM_design
  >GDS_LAYER_MAP_FILE: mapping_map
  >METAL_FILL_POLYGON_HANDLING: FLOATING
  >EXTRACTION: RC
  >COUPLE_TO_GROUND: NO
  >MODE: 400
  >DENSITY_BASED_THICKNESS: YES
  >METAL_FILL_POLYGON_HANDLING: FLOATING
  >COUPLING_MULTIPLIER: 1
  >COUPLING_ABS_THRESHOLD: 5E-16
  >COUPLING_REL_THRESHOLD: 0.03
  >REDUCTION: NO_EXTRA_LOOPS
  >NUM_CORES: 4
  >CORNERS_FILE: ./corner.smc
  (CORNER_NAME: typical_79
  TCAD_GRD_FILE: ./typical.nxtgrd
  OPERATING_TEMPERATURE: 70)
  >SIMULATANEOOUS_MULTI_CORNER: YES
  >SELECTED_CORNERS: typical_70
  >POWER_PORTS: VDD VSS
  >CELL_TYPE: LAYOUT
  >NET_TYPE: LAYOUT
  >XREF: NO

• QRC Flow:

  >distribured_processing -multi_cpu 16
  >input_db -type def -design_file ./design.def.gz -lef_file_list cell.lef
  >>input_db -type metal_fill -gds_file ./design.dummy_metal.gds.gz
  >extraction_setup -stream_layer_map M1 3300 151 fill 1 ...
  >graybox -type lef_obstruction
  >process_technology -technology_library_file ./techfile -technology_name N16 -technology_corner typical -temperature 70
  >capacitance -decoupling_factor 1.0 -mode high
  >extraction_setup -max_fracture_length 25 -enable_dpt_corlor_import true -technology_layer_map M1 M1 ...
  >extracct -selection all -type rc_coupled
  >hierarchical_extract -hierarchical_cell_list_file ./macros.cellllist
  >parasitic_reduction -enable_reduction false
  >extract -selection 'net *VDD*' -type none
  >extract -selection 'net *VSS*' -type none
  >metal_fill -type 'floating'
  >output_setup -compressed true -enable_short_check all -write_incomplete_shorts_nets_file true
  >output_db -type spef -hierarchy_delimiter '/' -output_incomplete_nets true -output_unrouted_nets true -subtype 'standard'
  > filter_coupling_cap -cap_filtering_mode absolute_and_relative -total_cap_threshold 0 -coupling_cap_threshold_absolute 0.1 -coupling_cap_threshold_relative 1
  >output_setup -file_name design.spef -directory_name ../spef/ -file_max_size 200000000
  >log_file -dum_option true -max_warning_messages 100 -file_name ./log/qrc.log
  >log_file -strict_error_report true -abort_upon_missing_macro true
  

5，参考文献

1，Fusion Compiler/ IC Compiler 2 user guide

2，Innovus user guide

3，StarRC user guide

4，Quantus user guide