Test structure for electrically measuring the degree of misalignment between successive layers of conductors

• US 6,380,554 B1
• Filed: 06/08/1998
• Issued: 04/30/2002
• Est. Priority Date: 06/08/1998
• Status: Expired due to Fees

• Current Assignee: Advanced Micro Devices, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Gardner, Mark I., Fulford, H. Jim Jr., Bush, John J.
• Primary Examiner(s): Cao, Phat X.
• Application Number:
  US09/093,358
• Time in Patent Office: 1,422 Days
• Field of Search: 257/48, 257/758, 438/11, 438/13, 438/14
• US Class Current: 257/48
• CPC Class Codes: G03F 7/70633 Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
• CPC Class Codes: G03F 7/70658 Electrical testing
• CPC Class Codes: H01L 22/34 Circuits for electrically characterising or monitoring manufacturing processes, e. g. whole test die, wafers filled with test structures, on-board-devices incorporated on each die, process control monitors or pad structures thereof, devices in scribe line switching, multiplexing, gating devices G01R19/25; process control with lithography, e.g. dose control, G03F7/20; structures for alignment control by optical means G03F7/70633
• CPC Class Codes: H01L 2924/3011 Impedance

Abstract

The present invention advantageously provides a test structure and method for using electrical measurements to determine the overlay between successive layers of conductors lithographically patterned upon a semiconductor topography. According to an embodiment, a test structure is provided which includes first, second, and third conductive structures having first, second, and third corner regions, respectively. Alternatively, the conductive structures may include only a single conductive structure having three corner regions. Each corner region is bounded by a pair of outer lateral edges configured substantially perpendicular to one another. First, second, and third conductors are operably coupled to the first, second, and third corner regions, respectively, such that overlapping areas of the conductors arranged directly above the corner regions are substantially rectangular in shape. The layout design for the test structure specifies the targeted dimensions, x and y, of each overlapping area. Fabrication of the test structure may result in the overlapping areas being shifted from their targeted positions such that their dimensions are larger or smaller than their targeted values. The amount by which the overlapping areas are shifted in the x direction is known as Δx, and the amount by which the overlapping areas are shifted in the y direction is known as Δy. The contact resistances between the overlapping areas of the conductors and the corner regions may be found and substituted into equations for Δx and Δy.

Claims

1. An integrated test circuit structure comprising three overlap areas arranged directly between respective overlying conductors and underlying conductors, wherein a corner region of at least one of the underlying conductors is positioned directly below one of the overlap areas, wherein dimensions of the overlap areas are dependent on alignment of the overlying conductors relative to the underlying conductors, wherein an entirety of an upper surface of the corner region is in direct contact with a contact conductor, and wherein the contact conductor comprises a contact extending vertically between the respective underlying conductor and the corresponding overlying conductor.

2. An integrated test circuit structure comprising three overlap areas arranged directly between respective overlying conductors and underlying conductors, wherein a corner region of at least one of the underlying conductors is positioned directly below one of the overlap areas, wherein dimensions of the overlap areas are dependent on alignment of the overlying conductors relative to the underlying conductors, wherein an entirety of an upper surface of the comer region is in direct contact with a contact conductor, wherein the underlying conductors are spaced laterally apart from each other, wherein the underlying conductors are operably coupled to the respective overlying conductors, and wherein each of the overlying conductors comprises a pair of arms configured substantially perpendicular to each other, and further comprising conductive pads connected to each of the pair of arms.

3. An integrated test circuit structure comprising three overlap areas arranged directly between respective overlying conductors and underlying conductors, wherein a corner region of at least one of the underlying conductors is positioned directly below one of the overlap areas, wherein dimensions of the overlap areas are dependent on alignment of the overlying conductors relative to the underlying conductors, wherein an entirety of an upper surface of the corner region is in direct contact with a contact conductor, and wherein the underlying conductors are adjoined such that they form a substantially rectangular loop, and wherein the underlying conductors are operably coupled to the respective overlying conductors.

4. The integrated circuit test structure of claim 3, wherein the underlying conductors directly contact the respective overlying conductors.

5. The integrated circuit test structure of claim 3, further comprising contacts extending vertically between the underlying conductors and the respective overlying conductors.

6. An integrated circuit test structure comprising three overlap areas arranged directly between respective overlying conductors and underlying conductors, wherein the underlying conductors are adjoined such that they form a substantially rectangular loop comprising four comer regions, and wherein dimensions of the overlap areas are dependent on alignment of the overlying conductors relative to the underlying conductors, and, wherein three of the corner regions are positioned directly below the respective overlap areas.

7. The integrated circuit test structure of claim 6, wherein the underlying conductors are operably coupled to the respective overlying conductors.

8. The integrated circuit test structure of claim 6, wherein the rectangular loop comprises four members connecting the four comer regions to each other.

9. The integrated circuit test structure of claim 8, further comprising respective conductive lines operably coupled to the members and extending laterally to respective probe pads.

10. The integrated circuit test structure of claim 6, wherein each of the overlying conductors comprises a pair of arms configured substantially perpendicular to each other, and further comprising conductive pads connected to each of the pair of arms.

11. The integrated circuit of claim 6, wherein the overlap areas are substantially rectangular in shape.

12. The integrated circuit of claim 6, wherein the three corner regions are positioned directly below the respective overlap areas such that they are in electrical communication with the respective overlap areas.