Derived Layers

A derived layer is composed as the result of a binary operation between two other layers that may be derived or physical. The layers used as operands for the binary operation must be of a lower layer number compared to the layer to be composed. The SELECT operation is the only operation supported by the extractor where the second operand is a “purpose” instead of a “layer”. If a derived layer with an unsupported operation is processed by the extractor, a warning message is issued.

Consider the following definition in the techDerivedLayers section of a technology file.

(D1 10001 (M1 'select drawing))

(D2 10002 (M2 'select pin))

(D3 10003 (M2 'select drawing))

(D4 10004 (D2 'or D3))

(D5 10005 (D4 'or D1))

(validLayers (D5))

Here:

• D5 represents the list of physical layers: (M1 drawing), (M2 pin), and (M2 drawing). These physical layers are extractable because D5 is defined in the validLayers constraint.
• D4, D3, D2, and D1 are “intermediate derived layers”
  • Top and intermediate derived layers only support the OR or SELECT operations.
  • AND, NOT, and INSIDE are supported as top derived layers.
  • GROW, AND, and COLOR are supported in intermediate derived layers for the operands of NOT.
  • The first operand of INSIDE can only be a NOT derived layer. The second operand of INSIDE can only be a physical layer or a SELECT derived layer.
  • The first operand of COLOR can only be a physical layer.

Related Topics

dbSetSoftConnectTermPinlessLayer

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