Multiple directional scans of test structures on semiconductor integrated circuits

• US 7,656,170 B2
• Filed: 02/14/2007
• Issued: 02/02/2010
• Est. Priority Date: 04/18/2000
• Status: Expired due to Fees

• Current Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Original Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Inventors: Walker, David J., Leslie, Brian C., Long, Robert Thomas, Pinto, Gustavo A., Satya, Akella V. S., Adler, David L.
• Primary Examiner(s): Nguyen; Vinh P
• Application Number:
  US11/675,013
• Publication Number:
  US 20080237487A1
• Time in Patent Office: 1,084 Days
• Field of Search: None
• US Class Current: 324/754.22
• 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 23/5226 Via connections in a multilevel interconnection structure
• 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

Disclosed is a method of inspecting a sample. The sample is scanned in a first direction with at least one particle beam. The sample is scanned in a second direction with at least one particle beam. The second direction is at an angle to the first direction. The number of defects per an area of the sample are found as a result of the first scan, and the position of one or more of the found defects is determined from the second scan. In a specific embodiment, the sample includes a test structure having a plurality of test elements thereon. A first portion of the test elements is exposed to the beam during the first scan to identify test elements having defects, and a second portion of the test elements is exposed during the second scan to isolate and characterize the defect.

Claims

1. A method of inspecting a sample, comprising:

a. in a first direction, scanning the sample with at least one particle beam;

b. in a second direction, scanning the sample with at least one particle beam, the second direction being at an angle to the first direction,

wherein a number of defects per an area of the sample are found as a result of the first scan and a position of one or more found defects is determined from the second scan when one or more defects are found from the first scan.

2. The method of claim 1, wherein the same particle beam is used to perform both steps a and b.

3. The method of claim 1, wherein the relative motion in at least one of steps a and b is provided by moving a stage carrying the sample.

4. The method of claim 1, wherein the particle beam travels through a column and the relative motion in at least one of steps a and b is provided by moving a column with respect to the sample.

5. The method of claim 1, wherein the relative motion in at least one of steps a and b is provided by deflecting the particle beam.

6. The method of claim 1, wherein the sample is moved relative to the at least one beam during the first scan at a substantially constant velocity.

7. The method of claim 1, wherein the first direction and the second direction are substantially orthogonal to one another.

8. The method of claim 1, wherein the sample includes a test structure having a plurality of test elements thereon, and wherein a first portion of the test elements is exposed to the beam during the first scan to identify test elements having defects based on a voltage contrast image resulting from such first scan, and a second portion of the test elements are exposed during the second scan to isolate and characterize the defect based on a voltage contrast image resulting from such second scan.

9. The method of claim 8, wherein the first portion and second portion at least partially overlap.

10. The method of claim 8, wherein the first portion and the second portion are not entirely coextensive.

11. The method of claim 8, wherein defects present in the test elements are located as a result of exposing the test elements in the second direction.

12. The method of claim 8, wherein the test elements are elongated along a line substantially parallel to the second direction.