PERIODIC PATTERNS AND TECHNIQUE TO CONTROL MISALIGMENT BETWEEN TWO LAYERS

• US 20090231584A1
• Filed: 04/22/2009
• Published: 09/17/2009
• Est. Priority Date: 04/10/2001
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation (KLA Corporation)
• Original Assignee: KLA-Tencor Corporation (KLA Corporation)
• Inventors: Friedmann, Michael, Abdulhalim, Ibrahim, Adel, Mike, Faeyrman, Michael
• Granted Patent: US 8,525,994 B2
• Time in Patent Office: Days
• US Class Current: 356/401
• 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.

2. The target of claim 1, wherein said second periodic structure extends into an area where said first periodic structure does not extend.

3. 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 with said first periodic structure;

wherein said first or periodic structure has at least two interlaced grating lines having different periods, line widths or duty cycles.

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

5. The target of claim 3, said at least two interlaced grating lines having different line widths.

6. A method for detecting misalignment between a first periodic structure and a second periodic structure of a device, said second periodic structure overlying or interlaced with said first periodic structure, comprising:

measuring critical dimensions of the first and second periodic structures, wherein measurement of at least one of the first and second periodic structures is performed without measuring the other one of the first and second periodic structures; and

measuring the misalignment between the first and second periodic structures.

7. The method of claim 6, 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, and said critical dimension of the second periodic structure is measured by measuring said second portion of said second periodic structure.