Aligned logic cell grid and interconnect routing architecture
A method for defining an aligned logic cell grid and interconnect layout of a semiconductor integrated circuit having a logic cell is disclosed. The interconnect layout is resized in accordance with a highest common denominator of an initial routing pitch of the interconnect layout and a transistor pitch of the logic cell. The cell grid is aligned with the resized routing pitch which provides efficient routing density and transistor performance, minimizes excess transistor area and wire routing waste while maximizing cell packing density.
1. A method for defining an aligned logic cell grid and interconnect layout of a semiconductor integrated circuit having a logic cell, comprising:
providing a semiconductor integrated circuit having an initial interconnect and an initial cell grid layout logic cell arrangement, the logic cell comprising transistor components having a minimum transistor width defining a natural transistor pitch, the interconnect layout comprising tracks for interconnecting the transistor components having a track width and track spacing defining an initial routing pitch, the natural transistor pitch and the initial routing pitch in misalignment;
resizing the initial routing pitch to a resized routing pitch by scaling the initial routing pitch by a fraction 1/q, wherein q is an integer greater than 1 and wherein q is selected such that the resized routing pitch is scalable on a manufacturing grid;
resizing the natural transistor pitch to a resized transistor pitch by scaling the resized routing pitch by an integer k, wherein k is selected such that the resized transistor pitch is greater than or equal to the natural transistor pitch; and
aligning the cell grid having the resized transistor pitch with the interconnect layout having the resized routing pitch to form an aligned cell grid and interconnect layout of the logic cell.
2. The method of claim 1 wherein the natural transistor pitch correlates with an industry standard minimum required for the transistor width, and the initial routing pitch correlates with an industry standard minimum required for wire spacing and width.
3. The method of claim 1 wherein the initial routing pitch is resized in accordance with a highest common denominator of the initial routing pitch and the natural transistor pitch to eliminate the misalignment.
4. The method of claim 3 wherein the highest common denominator selected is based on the minimum pitch between tracks of the initial interconnect layout.
5. The method of claim 4 further comprising calculating a compare routing pitch to compare with the resized routing pitch based on the highest common denominator to determine the most desired routing pitch in view of transistor pitch efficiency versus increased run-time due to the number of grids.
6. The method of claim 3 further comprising calculating a compare routing pitch to compare with the resized routing pitch based on the highest common denominator to determine the most desired routing pitch in view of transistor pitch efficiency versus increased run-time due to the number of grids.
7. The method of claim 1 wherein the resized routing pitch is a quarter of the initial routing pitch.
8. The method of claim 1 wherein the resized routing pitch is a fifth of the initial routing pitch.
9. The method of claim 1 wherein the resized routing pitch is a sixth of the initial routing pitch.
10. The method of claim 1 wherein the resized routing pitch is a seventh of the initial routing pitch.