150:(example: if a resistor in a schematic had resistance=1000 (ohms) and the extracted netlist had the a matched resistor with resistance=997(ohms) and the tolerance was set to 2%, then this device parameter would pass as 997 is within 2% of 1000 ( 997 is 99.7% of 1000 which is within the 98% to 102% range of the acceptable +-2% tolerance error) )
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can contain properties. The LVS tool can be configured to compare these properties to a desired tolerance. If this tolerance is not met, then the LVS run is deemed to have a
Property Error. A parameter that is checked may not be an exact match, but may still pass if the lvs tool tolerance allows it.
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use polygon areas as inputs and generate output polygon areas from these operations. These operations are used to define the device recognition layers, the terminals of these devices, the wiring conductors and via structures, and the locations of pins (also known as hierarchical connection points).
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Comparison: The extracted layout netlist is then compared to the netlist taken from the circuit schematic. If the two netlists match, then the circuit passes the LVS check. At this point it is said to be "LVS clean." (Mathematically, the layout and schematic netlists are compared by performing a
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The layers that form devices can have various measurements performed to and these measurements can be attached to these devices. Layers that represent "good" wiring (conductors) are usually made of and called metals. Vertical connections between these layers are often called vias.
73:, checking whether the schematic and layout were indeed identical. With the advent of digital logic, this was too restrictive, since exactly the same function can be implemented in many different (and non-isomorphic) ways. Therefore, LVS has been augmented by
65:(DRC) ensures that the layout conforms to the rules designed/required for faultless fabrication. However, it does not guarantee if it really represents the circuit you desire to fabricate. This is where an LVS check is used.
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The need for such programs was recognized relatively early in the history of ICs, and programs to perform this comparison were written as early as 1975. These early programs operated mainly on the level of
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In most cases the layout will not pass LVS the first time requiring the layout engineer to examine the LVS software's reports and make changes to the layout. Typical errors encountered during LVS include:
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Extraction: The software program takes a database file containing all the layers drawn to represent the circuit during layout. It then runs the database through many area based
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LVS checking software recognizes the drawn shapes of the layout that represent the electrical components of the circuit, as well as the connections between them. This
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Opens: Wires or components that should be connected are left dangling or only partially connected. These must be connected properly to fix this.
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Reduction: During reduction the software combines the extracted components into series and parallel combinations if possible and generates a
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Component
Mismatches: Components of an incorrect type have been used (e.g. a low Vt MOS device instead of a standard Vt MOS device)
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to determine the semiconductor components represented in the drawing by their layers of construction. Area based
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representation of the layout database. A similar reduction is performed on the "source" Schematic netlist.
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Shorts: Two or more wires that should not be connected have been and must be separated.
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297:. Proceedings of the 12th Design Automation Conference. IEEE Press. pp. 414–420.
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is compared by the "LVS" software against a similar schematic or circuit diagram's
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Missing
Components: An expected component has been left out of the layout.
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41:(EDA) verification software that determines whether a particular
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Electronic Design
Automation For Integrated Circuits Handbook
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96:LVS checking involves following three steps:
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16:Type of electronic circuit design software
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145:Parameter Mismatch: Components in the
307:Fabio Somenzi and Andreas Kuehlmann,
294:An artwork design verification system
124:check to see if they are equivalent.)
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315:, by Lavagno, Martin, and Scheffer,
272:http://opencircuitdesign.com/netgen/
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339:Electronic circuit verification
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45:corresponds to the original
39:electronic design automation
311:, chapter 4 (volume 2) of
291:Baird, HS; Cho, YE (1975).
75:formal equivalence checking
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43:integrated circuit layout
209:Magma Design Automation
31:Layout Versus Schematic
182:Cadence Design Systems
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309:Equivalence Checking
264:https://klayout.de/
160:Commercial software
106:logical operations
37:) is the class of
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225:-now SmartLVS by
122:Graph isomorphism
71:graph isomorphism
63:design rule check
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278:References
205:Quartz LVS
57:Background
47:schematic
333:Category
249:Zeni EDA
232:SmartLVS
223:PowerLVS
218:Synopsys
155:Software
25:LVS flow
261:KLayout
236:Silvaco
227:Silvaco
200:Silvaco
187:Calibre
178:Pegasus
170:Dracula
147:netlist
114:netlist
91:netlist
87:netlist
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269:Netgen
166:Assura
245:HVERI
81:Check
317:ISBN
243:and
241:VERI
176:and
29:The
247:by
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216:by
207:by
198:by
189:by
180:by
174:PVS
49:or
35:LVS
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33:(
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