Periodic patterns and technique to control misaligment between two layers

• US 8,525,994 B2
• Filed: 04/22/2009
• Issued: 09/03/2013
• Est. Priority Date: 04/10/2001
• Status: Expired due to Fees

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Abdulhalim, Ibrahim, Adel, Mike, Friedmann, Michael, Faeyrman, Michael
• Primary Examiner(s): Toatley, Gregory J
• Assistant Examiner(s): Valentin, II, Juan D
• Application Number:
  US12/428,401
• Publication Number:
  US 20090231584A1
• Time in Patent Office: 1,595 Days
• Field of Search: None
• US Class Current: 356/400
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• 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: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 2223/54426 for alignment
• CPC Class Codes: H01L 2223/54453 for use prior to dicing
• CPC Class Codes: H01L 2223/5446 Located in scribe lines
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• 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 and system to measure misalignment error between two overlying or interlaced periodic structures are proposed. The overlying or interlaced periodic structures are illuminated by incident radiation, and the diffracted radiation of the incident radiation by the overlying or interlaced periodic structures are detected to provide an output signal. The misalignment between the overlying or interlaced periodic structures may then be determined from the output signal.

Claims

1. A target for measuring the relative positions between two layers of a device, said target comprising:

a first periodic structure over a first layer of the device; and

a second periodic structure over a second layer of the device, said second periodic structure overlying or interlaced with said first periodic structure, wherein said second periodic structure includes a first and a second portion, wherein the first portion is in a region overlying the first periodic structure and the second portion is in a region not overlying the first periodic structure, wherein said first and second periodic structures are periodic in a first direction, and said second periodic structure extends in a direction that is different from the first direction into said region where the two structures do not overlap and where said first periodic structure does not extend.

2. A target for measuring the relative positions between two layers of a device, said target comprising:

a first periodic structure over a first layer of the device; and

a second periodic structure over a second layer of the device, said second periodic structure overlying or interlaced with said first periodic structure and;

wherein said first or second periodic structure has at least two periodic gratings with grating lines that are interlaced, each of said two periodic gratings formed by a repeating pattern wherein a period of each of said two periodic gratings is a distance after which the pattern of such periodic grating is repeated, said at least two periodic gratings having different periods, line widths or duty cycles.

3. The target of claim 2, said at least two interlaced grating lines having different duty cycles.

4. The target of claim 2, said at least two interlaced grating lines having different line widths.

5. The target of claim 2, wherein the first and second periodic structures are interlaced with each other.

6. The target of claim 2, wherein the first and second periodic structures are substantially in the same plane.

7. The target of claim 2, wherein the first and second periodic structures are on the same substrate.

8. A method for measuring the relative positions between two layers of a device and a critical dimension in at least one of the layers, said two layers comprising:

a first periodic structure over a first layer of the device; and

a second periodic structure over a second layer of the device, said second periodic structure overlying or interlaced with said first periodic structure, wherein said second periodic structure includes a first and a second portion, wherein the first portion is in a region overlying the first periodic structure and the second portion is in a region not overlying the first periodic structure, wherein said first and second periodic structures are periodic in a first direction, and said second periodic structure extends in a direction that is different from the first direction into said region where the two structures do not overlap and where said first periodic structure does not extend and wherein one dimension of the second is the critical dimension;

said method comprising;

measuring the relative positions between two layers; and

measuring the critical dimension using an optical system wherein only the critical dimension of said second periodic structure in said region is measured.