LAYOUT DETERMINING FOR WIDE WIRE ON-CHIP INTERCONNECT LINES

• US 20110179392A1
• Filed: 03/23/2011
• Published: 07/21/2011
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Tretiakov, Youri V., Tallman, Kurt Alan, Strang, Sue Ellen, Goren, David, Gordin, Rachel
• Granted Patent: US 8,943,456 B2
• Time in Patent Office: Days
• US Class Current: 716/52
• CPC Class Codes: H01L 21/7684 Smoothing; Planarisation
• CPC Class Codes: H01L 23/5225 Shielding layers formed together with wiring layers
• CPC Class Codes: H01L 23/528 Geometry or layout of the interconnection structure H01L27/0207 takes precedence; algorithms G06F30/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method for determining the layout of an interconnect line is provided including: providing a required width for the interconnect line; determining a layout of the interconnect line including slotting the interconnect line to provide two or more fingers extending along the interconnect line with an elongate slot separating adjacent fingers; and determining a number of elongate apertures to be arranged across the width of the interconnect line by comparing the required width with a maximal width for a solid metal feature, and a minimal elongate aperture width. The two or more fingers and elongate slot may be of constant width and equally spaced across the interconnect line width. The method may include selecting the number of fingers and the width of the slots to optimize the layout for a given layer technology.

Claims

1. A method for determining the layout of an interconnect line, comprising:

having a required width for the interconnect line; and

determining a number of elongate apertures to be arranged across the width of the interconnect line by comparing the required width with a maximal width for a solid metal feature, and a minimal elongate aperture width;

wherein said steps are implemented in either;

computer hardware configured to perform said providing and determining steps, or

computer software embodied in a non-transitory, tangible, computer-readable storage medium.

2. The method as claimed in claim 1, including:

determining a layout of the interconnect line including slotting the interconnect line to provide two or more fingers extending along the interconnect line with an elongate slot separating adjacent fingers.

3. The method as claimed in claim 1, including providing a required width for the interconnect line greater than a maximum threshold width for a given layer technology.

4. A method as claimed in claim 1, wherein the method includes ensuring that the density of the metal of the interconnect line falls within a predetermined range.

5. A method as claimed in claim 1, wherein the method includes arranging the elongate apertures symmetrically across the width of the interconnect line.

6. The method as claimed in claim 1, including:

selecting the number of fingers and the width of the slots to optimize the layout for a given layer technology.

7. The method as claimed in claim 1, wherein the maximum threshold width W_max for a given layer technology is specified by Physical Design Rules for the layer technology.

8. The method as claimed in claim 1, wherein determining a layout includes determining a number of slots N_slots as the largest integer not greater than ((w−

W_low)/(W_slot+W_low)) where W_low=K_slot*(W_max−

W_slot), wherein w is the width of the interconnect line, W_low is the minimal value of a finger width, W_slot is the width of the slots, W_max is the maximum threshold width of the interconnect line, and K_slot is a factor of less than 1 which defines the onset of slotting.

9. The method as claimed in claim 1, including:

selecting parameters of the slot width W_slot, and a factor K_slot of less than 1 which defines the onset of slotting which are constant for a given layer technology, independent of the width of the interconnect line.

10. The method as claimed in claim 9, including:

selecting a value for the parameter of slot width W_slot as the minimum slot width S_n which complies with the Physical Design Rules for any wire width in a selected metal layer and is therefore the largest minimum slot width; and

selecting a value for the parameter K_slot for the onset of slotting as K_slot=W_n/(W_max−

S_n) where W_n is the minimum finger width for which the Physical Design Rules require space no less than S_n.

11. The method as claimed in claim 9, wherein the parameters are chosen so that a resultant slotted interconnect line has a maximal metal density whilst complying with other predefined conditions.

12. The method as claimed in claim 11, wherein a predefined condition is that the width of the fingers is no less than a minimum width for the layer technology as specified by Physical Design Rules for the layer technology.

13. The method as claimed in claim 11, wherein a predefined condition is that the width of the fingers does not require optical proximity correction.

14. The method as claimed in claim 11, wherein a predefined condition is that the width of the fingers and the width of the slots comply with the Physical Design Rules for a layer technology.

15. The method as claimed in claim 11, wherein a predefined condition is that the metal density complies with the Metal Density Rules.

16. The method as claimed in claim 1, wherein the layer technology is a back end of the line technology.

17. A method as claimed in claim 1, wherein the method also includes:

having a required length for the interconnect line;

determining a number of bridges to be arranged along an elongate aperture by comparing the required length to a maximum elongate aperture length and a minimum width of bridge.

18. A method as claimed in claim 1, wherein the method includes placing a bridge at each end of the interconnect line and symmetrically spacing any additional bridges along an elongate aperture.

19. A method as claimed in claim 17, wherein the maximum elongate aperture length is less than a tenth of the shortest wavelength to be carried along the interconnect line.

20. A computer program product for determining the layout of an interconnect line, the computer program product comprising:

a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising;

computer readable program code configured to;

receive a required width for an interconnect line; and

determine a number of elongate apertures to be arranged across the width of the interconnect line by comparing the required width with a maximal width for a solid metal feature, and a minimal elongate aperture width.