MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第615页

MIL-STD-883F METHOD 5004.11 18 June 2004 25 APPENDIX A ATTACHMENT 3 In-l ine elec tric al tes t (E -tes t): Thi s monit or is used to meas ure elec tri cal c harac teri sti cs of trans ist or element s (s heet resi stanc…

MIL-STD-883F

METHOD 5004.11

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APPENDIX A

ATTACHMENT 3

ANALYTICAL TOOLS/MONITORS AND SCREENS

Analytical tools may include, but are not limited to the following:

a. Oblique light, very low magnification

b. Optical microscope

c. Laser scattering (or equivalent)

d. Automated pattern inspection

e. Alignment measurement tool (automated, high-resolution)

f. Non-destructive S.E.M.

g. Wafer mapping

Broad Use of Tools for Inspections (tools may include but are not limited to):

Oblique Light, visual inspection: A quick and gross visual inspection at very low mag (1X to 20X) using a light source

projected onto the wafer and tilting the wafer to detect large particles. This is an inspection step used in-line at various key

process steps.

Optical microscope: Looks for defects that are detectable optically (eg: metal stringers, large particles, visible foreign

material, visible resist imperfections such as drips, visible voids and cracks, visible misalignment, etc.). This tool is used at

different magnifications, at beginning and/or end of key process steps (200X optical sampling in-line for a selected key

process step and 800X optical check at the end of a key process step and before proceeding to the next key process step).

Laser scanning (or equivalent): Used to detect any anomalous surface defects (eg: very fine particles that may not be

detected by optical microscopy). May be used in numerous process steps and is particularly important early in the process

to control telescoping defects.

Automated Pattern recognition: Used to verify integrity of two dimensional geometries (detects anomalies such as: voids

and cracks in the metal, metal bridging, diffusion and poly faults or any other abnormalities in an expected pattern).

Automated high resolution alignment measurement tool: Used for inter-level registration at very fine tolerances (on the

order of 0.1 µm). This tool is used to align very fine critical geometries undetectable by conventional high power optical

registration tools.

Non-destructive S.E.M.: In-line product monitor used for very high power visual examination of critical process steps

(critical dimension, step coverage, metal thinning, etc.).

wafer mapping: An analytical technique using data from various inspection tools (eg: automated pattern recognition tools,

laser scanning tools, e-test results) for defect characterization and partitioning.

Product, Process and Reliability Monitors/Screens

These monitors/screens incorporate inspections/tests which may include but are not limited to):

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METHOD 5004.11

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APPENDIX A

ATTACHMENT 3

In-line electrical test (E-test): This monitor is used to measure electrical characteristics of transistor elements (sheet

resistance, doping levels and other transistor parametrics), contact chains, metallization structures (line width, thickness,

resistance) and via structures. Parametric failures detectable by e-test may be indicative of an unacceptable incidence of

killer or critical defects.

Test structures: Special structures used to detect killer or critical defects (eg: serpentine structures used to detect metal

continuity such as voids, comb structures for bridge detection and to verify field oxide isolation integrity, electromigration

structures to verify metal integrity and step coverage and inter-layer dielectric structures to verify e-field integrity).

Periodic reliability studies: Intended to verify design life margins of the technology.

Yield Analysis: Used to validate effectiveness of in-line monitors by a closed loop feedback system that detects the

effects of killer or critical defect escapes not caught in-line. Actions may include: scrapping lot, root cause analysis and

correction, lot screening, etc. (see section 70).

Other monitors: Used to measure key process elements. Examples may include but are not limited to:

a. Metal reflectivity and resistivity (to check metal irregularities such as: hillocks formations, step thinning, changes in

granularity, voiding, etc.).

b. Ionic contamination.

c. Refractive index for interlayer dielectric thickness measurements.

d. Post wafer probe visual inspection. A monitor performed on randomly selected post probe wafer(s) beginning with

visual high power inspection and may be followed by subsequent detailed analysis (S.E.M., EDX, layer strip-back,

etc.). This is used to confirm the effectiveness of in-line monitors.

e. Acid bath (used for quick detection/ decoration of glassivation defects, cracks and holes) or acoustic microscopy

(to measure glassivation integrity).

Equipment Monitors (equipment monitors may include but are not limited to):

Particle checks: Performed on process equipment such as: etch, metal deposition, implant, diffusion, dielectric

deposition, photoresist material and application. Particles of sufficient size and density may lead to killer or critical defects

(metal bites, dielectric holes, poly/ diffusion geometry changes, etc.).

Residual Gas Analysis: Used to monitor gas integrity of key process equipment (eg: metal deposition equipment to

control corrosion).

Photolithography exposure equipment: Used to verify critical parameters and controls for photolithography operation (pre-

alignment checks, stage accuracy, machine alignment accuracy using reference patterns, lens distortion check, alignment

accuracy, wafer chuck flatness measurement, lens focus check, reticle rotation, etc.)

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