Conductive line width and resistivity measuring system

• US 3,974,443 A
• Filed: 01/02/1975
• Issued: 08/10/1976
• Est. Priority Date: 01/02/1975
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Thomas, Donald Ralph
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/538,288
• Time in Patent Office: 586 Days
• Field of Search: 324/64, 324/62, 324/65 R, 324/158 R, 29/574
• US Class Current: 324/716
• CPC Class Codes: G01R 27/08 Measuring resistance by measuring both voltage and current
• CPC Class Codes: G01R 31/2853 Electrical testing of internal connections or -isolation, e.g. latch-up or chip-to-lead connections G01R31/31717 takes precedence; test of chip-to-PCB or lead-to-PCB connections G01R31/66

Abstract

Method and apparatus for measuring or determining characteristics, such as width and resistivity of a given conductive line, particularly a conductive line produced by integrated circuit technology. The conductive line, having a first width which is formed on an insulating medium is disposed in the vicinity of or adjacent to a second line having a second width different from the first width, which is also conductive and which is made by the same process by which the given conductive line was made. A common constant current is passed through the given conductive line and through the second line. A first voltage is measured between two points spaced apart by a given distance along the given conductive line and a second voltage is measured between two points spaced apart by the given distance along the second line. Characteristics, such as width and resistivity, of the given conductive line, as well as those of the second line, are then determined by utilizing relationships between the measured voltages and known line constants.

Claims

1. A measuring system comprising

a first conductive line having a known first nominal width, a second conductive line having a known second nominal width, means for passing current of equal value through each of said lines, and means for measuring the voltage between two points on each of said lines spaced apart by equal distances to determine in relationship with said first and second nominal widths characteristics of said conductive lines.

2. A measuring system as set forth in claim 1 wherein one of said characteristics is line width variation from said nominal widths derived in accordance with the relationship ##EQU7## where V₁ and V₂ are the voltages between the two points on the first and second lines, respectively, and W_1N and W_2N are the nominal width of the first and second lines, respectively.

3. A measuring system as set forth in claim 1 further comprising means for measuring current flow through said lines and wherein one of said characteristics is resistivity derived in accordance with the relationship ##EQU8## where V₁ and V₂ are the voltages between the two points on the first and second lines, respectively, W_1N and W_2N are the nominal width of the first and second lines, respectively, L is the distance between said two points and I is the current flowing through said lines.

4. A measuring system as set forth in claim 1 wherein said measuring means includes a probe pad connected to each of said points.

5. A measuring system as set forth in claim 4 wherein said lines are disposed adjacent to each other on an insulating medium.

6. A measuring system as set forth in claim 5 wherein said first nominal width is similar in size to said second nominal width and said insulating medium forms a portion of a semiconductor integrated circuit.

7. A measuring system as set forth in claim 1 wherein said means for passing current includes probe pads connected to said first and second lines.

8. A method for measuring characteristics of conductive lines comprising

forming a first conductive line having a known first nominal width and a second conductive line having a known second nominal width,

passing equal amounts of current through said first and second conductive lines,

measuring the voltage between two points on each of said lines spaced apart by equal distances and

calculating characteristics of said conductive lines as relationships of the voltages with said first and second nominal widths.

9. A method as set forth in claim 8 wherein one of said characteristics is line width variation from said nominal widths derived in accordance with the relationship ##EQU9## where V₁ and V₂ are the voltages between the two points on the first and second lines, respectively, and W_1N and W_2N are the nominal width of the first and second lines, respectively.

10. A method as set forth in claim 8 further comprising measuring current flow through said lines and wherein one of said characteristics is resistivity derived in accordance with the relationship ##EQU10## where

11. V₁ and V₂ are the voltages between the two points on the first and second lines, respectively, W_1N and W_2N are the nominal width of the first and second lines, respectively, L is the distance between said two points and I is the current flowing through said lines.