MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第607页

MIL-STD-883F METHOD 5004.11 18 June 2004 17 APPENDIX A 90. Document ation and data r equirement s : 90.1 The res ults of defec t char acter izati on, ass ess ment of ef fect iveness of sc reening met hods, s ampling and …

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MIL-STD-883F
METHOD 5004.11
18 June 2004
16
APPENDIX A
50.3 Any in-line or end-of-line screens shall be defined, implemented and documented when used in lieu of, or to
supplement inspections/tests for killer and critical defects. The population to be screened must also be defined and
documented (eg: wafers, die, portions of wafers, wafer lots, etc.). These procedures shall only include those screens
proven to be effective, per requirements in section 40. Records of screening results must be maintained (accept/ reject
data).
50.4 The Analytical tools and product, process reliability and equipment monitors must have sufficient capability to
measure defect attributes as defined in section 40. This includes changes in critical defect density (eg: if defect
characterization indicates a 0.1 µm particle is a critical defect at a given mask level, the inspection procedure must be
capable of detecting and quantifying the incidence of particles this size and larger). See attachment #3: Analytical tools.
60. Excursion Containment for Material Exceeding Action Limits
:
60.1 The manufacturer shall confirm that the action limit has been exceeded. This may be accomplished by: record
review, reinspection, increased sampling, higher magnification visual, etc.
60.2 If the condition is confirmed, the manufacturer shall identify and act upon affected material (ie: single wafer, multiple
wafers, whole lot, batches of lots, whole line).
60.3 The manufacturer shall perform analysis on affected material and establish a disposition strategy (ie: root cause
analysis, scrap, screen, rework, etc.).
60.4 The manufacturer shall implement appropriate short term/long term corrective action (ie: screens, process change,
equipment change, design rule change, etc.)
70. Yield analysis
:
70.1 The manufacturer shall establish a yield analysis system as a monitor point to confirm effectiveness of inspections
and tests. Particular attention should be given to those lots that exhibit abnormal variation from expected yields, as defined
by the manufacturer.
70.2 Yield analysis should include root cause analysis to determine and drive process improvements.
70.3 The manufacturer shall coordinate the yield analysis system with a formal material review board (MRB), or other
approved disposition authority, to drive corrective action for "excursion" material (killer or critical defect escapes).
80. System for unexpected failure
:
80.1 The manufacturer shall establish a system to analyze field returns. Determine root cause of failure and drive action
for: identification, containment, disposition, notification and corrective action.
80.2 The manufacturer shall implement a system to capture and contain killer or critical defect escapes originating in
wafer fabrication but found elsewhere in the factory (ie: sort, assembly, test, etc.) and implement corrective action.
80.3 The manufacturer shall review unexpected failures through a formal material review board (MRB), or other approved
disposition authority, that brings together the expertise to identify and contain the discrepant product (killer or critical
defects), to notify internal and external customers, as needed and to implement corrective action. The circumstances for
convening an MRB must be defined.
MIL-STD-883F
METHOD 5004.11
18 June 2004
17
APPENDIX A
90. Documentation and data requirements
:
90.1 The results of defect characterization, assessment of effectiveness of screening methods, sampling and inspection
methodologies, procedures and systems for controlling changes shall be made available to the qualifying activity, upon
request.
90.2 Inspection and screening procedures must be placed under formal document and change control. Data records
must be maintained and made available to the qualifying activity, upon request. Data retention must be maintained in
accordance with the procurement specifications.
90.3 Excursion containment procedures must be documented and placed under document control. When appropriate,
records of root cause analysis, containment, disposition and corrective action (via an MRB or other approved disposition
authority) must be maintained and made available to the qualifying activity, upon request. Varying degrees of formality are
essential to any manufacturer's line; therefore, disposition authority may range from the responsible individual to a formal
MRB and documentation may range from initialing a lot traveler to a formal MRB report. The manufacturer shall have
prescribed guidelines for the various methods allowable for disposition action and documentation (eg: if product deviation is
within certain spec or action limits, the line engineer may have disposition authority; if these limits are exceeded, some
higher disposition authority may be required). Records must be retained in accordance with the procurement specifications.
100. Definitions:
(Note: The definitions herein are applicable to this procedure only)
Action limits
-Numerical limits for defect densities, counts, or other metrics used to trigger a response. This response may
involve: investigation, root cause analysis, disposition and corrective action.
Alignment
- Also known as "overlay" or "registration". The proper placement of one photolithography layer atop a
preceding layer.
Blown contact
- A phenomena most often associated with the wet etching of contacts. The etch proceeds laterally at a
rate much greater than is expected or desirable. Typically, the lateral etching is non-uniform with respect to the desired
contact profile.
Cornerholes
- A process phenomena associated with narrow gaps between lines of topography. In particular, where
those lines form an angle of approximately 90 degrees (form a "corner"). A cornerhole is formed when photoresist cannot
cover the severe topography generated by structures like these, allowing a subsequent etch to remove film in the gap
between the lines.
Critical Defects
- Defects known or suspected to cause premature failure but only under certain conditions that have a
small probability of occurrence or any defect that cannot be proven as non-critical.
Defect escapes
- Lots, wafers or die which contain defects that unintentionally get through a manufacturer's inspection
and test system.
DI (DI water)
- De-ionized water. Used for wafer cleaning.
Discrepant material
- any material determined to be unsuitable for its destined form, fit or function, as specified by the
MRB or other disposition authority.
Elements of the process
- Any fundamental piece (building block) of the wafer fab process or process step (eg: thermal
ramp rates, etch rates, recipe' steps, incoming raw materials, etc.). This includes quantifiable/ measurable chemical and
physical phenomena of the wafer fab process.
End-of-line
- The steps after wafer fabrication and initial testing (electrical test, wafer sort). This includes most of what is
commonly referred to as "assembly/test".
MIL-STD-883F
METHOD 5004.11
18 June 2004
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APPENDIX A
Excursion containment
- Efforts undertaken to find, limit and segregate discrepant material.
Homogeneous
- The state in which every wafer in a lot has received the exact same processing, including: correlated
equipment (as specified in appendix A of MIL-PRF-38535), same recipes, same operations and same materials. This
does not include metrology or inspection steps.
ILD - Inter-layer dielectric
. Typically refers to the layer separating different conductor material layers but is occasionally
used to describe the layer between first metal and the underlying layers.
In-line
- The process steps that comprise wafer fabrication from initial starting material through and including initial test
(electrical test and sort).
Inspection
- Any procedure designed to detect or measure defects. Depending on the equipment or procedure, the
quantity or types of defects may or may not be measurable; depending on the inspection, defects may or may not be
removed. These procedures may utilize visual detection (human or automated), laser surface scatter, in-situ particle
detectors, etc.
Interconnects
- Any structures on the wafer surface used for electrical connection from one device (or portion of a device)
to another. These structures are typically made of polysilicon or metal.
Killer defect
- A defect that has a high probability of causing failure, under any condition, at some given point in a products
intended life.
Letter of suitability
- A formal written document from the qualifying activity stating the manufacturer has sufficient capability
and competency to implement/execute the subject procedure.
Look-back inspection
- An inspection that is capable of detecting defects not only at the current process layer but also at
some number of preceding process layers. Ideally, this inspection allows for differentiation between defects at the current
process layer and those of preceding ones.
LPCVD
- Low-pressure chemical vapor deposition.
LTO
- Low-temperature oxidation or low-temperature oxide.
LYA
- Low-yield analysis. A method for determining the reason for yield loss by analyzing low-yielding material.
Mask level
- A structure (electrical, physical and/or chemical) on, in, above or below a wafer substrate, achieved or
modified by various sequential physical or chemical processes, such as: oxidation, diffusion, etch, film deposition, implant,
etc.
Material review board (MRB)
- A group of individuals who have sufficient expertise and are duly authorized by the facility
to disposition discrepant or non-conforming material.
Monitor
- Inspections or tests performed on a sampled population.
Non-critical defect
- A defect that has been demonstrated not to cause premature failure, regardless of defect density,
defect placement on the die or defect size.
PM
- Preventive maintenance procedure.
Poly
- Polycrystalline silicon.
Process baseline
- An approved set of instructions, conditions and procedures for wafer fabrication.
Product
- Material resulting from the output of a wafer fab process that is ultimately destined for delivery to a customer.