IPC-TM-650 EN 2022 试验方法--.pdf - 第176页
1 Scope 1. 1 Pu rp os e The s e t es t s a re us ed a s p ro ces s c ont r ol tools; they can be used to inspect printed boards or printed board as semblies and determine if they confo rm to the m oni- toring l evel of t…
Caution: Perform all work in a hood,
since vapors given off are toxic. Chemical goggles, com-
pletely enclosing the eyes, should be worn and eye wash
facilities should be readily available.
IPC-TM-650
Page 2 of 2
Number
2.3.24.2
Subject
Porosity
of
Metallic
Coatings
on
Copper-Base
Alloys
and
Nickel
(Nitric
Acid
Vapor
Test)
Date
8/97
Revision
A
Remove
the
part
from
the
desiccator
and
immediately
transfer
it
to
an
oven
at
125℃
for
30
minutes.
Remove
and
inspect
the
part
with
10
power
magnification
using
the
collimated
incandescent
light
source
arranged
so
that
the
light
beam
strikes
the
surface
being
examined
at
an
angle
of
less
than
1
5
degrees.
The
presence
of
blue,
green,
or
bluish-white
protru¬
sions
indicates
that
the
coating
is
discontinuous
(i.e.,
porous,
scratched,
etc.)
at
these
spots.
The
acceptable
number,
sizes,
and
location
of
these
protrusions
shall
be
as
specified
on
the
appropriate
drawing
or
specification.
3.2
Method
2
(Extended
Nitric
Acid
Vapor-Gold
on
Copper)
Procedure
This
method
is
an
extension
of
method
1
and
may
be
used
only
after
the
test
specimen
has
passed
the
requirements
of
the
visual
examination
with
the
collimated
light
source.
The
method
permits
the
determination
of
the
actual
sizes
of
the
larger
pores.
The
inspection
should
be
per¬
formed
as
indicated
below.
After
examining
the
oven-dried
test
specimen
in
accordance
with
Method
1
,
brush
the
corrosion
products
from
the
speci¬
men.
Inspect
the
area
where
the
corrosion
products
appeared
at
a
magnification
that
permits
measurements
of
the
largest
dimensions
of
the
discontinuities
with
reasonable
accuracy.
The
acceptable
distribution
of
pore
sizes
shall
be
as
specified
on
the
appropriate
drawing
or
specification.
3.3
Method
3
(Nitric
Acid
Vapor-Gold
on
Nickel)
3.3.1
Apparatus
The
apparatus
described
in
methods
1
and
2.
3.3.3
Procedure
Use
the
procedure
for
Method
1
up
to
removal
from
nitric
acid
vapors.
At
the
end
of
the
one
hour
exposure
to
the
nitric
acid
vapors,
remove
the
part
from
the
desiccator
and
immediately
dip
it
in
the
1
0
percent
by
weight
sodium
hydroxide
solution
for
25
to
30
seconds
at
room
temperature.
Rinse
the
part
with
water
and
then
dip
it
for
25
to
30
seconds
in
the
polysulfide
reagent
at
room
temperature.
Then
rinse
it
in
water
and
dry
using
fil¬
tered
compressed
air
(gage
pressure
less
than
207
kPa).
Inspect
the
part
at
10
power
magnification.
The
presence
of
black
corrosion
products
is
evidence
of
porosity.
The
accept¬
able
number,
sizes,
and
locations
of
pores
shall
be
as
speci¬
fied
on
the
appropriate
drawing
or
specification.
3.4
Polysulfide
Reagent
Makeup
Dissolve
sodium
sulfide
crystals
in
water
until
solution
is
saturated.
Add
excess
flow¬
ers
of
sulfur
(more
than
250
grams
per
1000
ml).
Stir
and
allow
solution
to
stand
24
hours.
Filter
and
dilute
with
water
to
a
specific
gravity
of
1
.142
at
room
temperature
as
defined
in
ASTM
Designation
E
41
.
The
solution
should
be
a
red-orange
color.
To
check
reagent
effectiveness,
dip
a
clean
copper
or
high
(more
than
95
percent)
copper
alloy
specimen
into
the
reagent
at
room
temperature
as
defined
in
ASTM
Designation
E
41
.
It
shall
blacken
within
1
0
seconds.
3.3.2
Reagents
Nitric
acid,
69.0
to
71
.0
percent
HN03.
Sodium
Hydroxide
10
percent
by
weight
solution.
Polysulfide
reagent.
1 Scope
1.1 Purpose
These tests are used as process control
tools; they can be used to inspect printed boards or printed
board assemblies and determine if they conform to the moni-
toring level of the user’s performance specification. Bulk ionic
cleanliness testing may be accomplished by measuring the
ionizable surface contaminants extracted by the following
three methods:
1. Manual extraction method
2. Dynamic extraction method
3. Static extraction method
Please note that this method does not predict reliabil-
ity and should only be used as a process control tool.
1.2 Restrictions
Measurements of ionic conductivities do
not differentiate between different ionic species. They simply
measure conductivities (or resistivities) which can be related to
amounts of ionic materials present in solution. There is no
identification of the contribution to the total conductivity read-
ings of any individual ionic species which may be extracted
into the solution. For measurement of individual ionic species
(type and level of residue) see IPC-TM-650, Test Method
2.3.28, Ionic Analysis of Circuit Boards, Ion Chromatography
Method.
For simplicity, amounts of ionic materials in solution can be
expressed by a conductivity factor which is equivalent to the
measured conductivity contributed by a known amount of a
standard, strongly ionized salt such as sodium chloride (NaCl).
Ionic residues are therefore usually expressed as equivalents
of sodium chloride in micrograms per unit surface area (e.g.,
µg NaCl Eq./cm
2
) of the sample. This does not imply that the
contamination is NaCl but, rather, it exhibits a conductivity
function which is equivalent to that of the expressed amount
of sodium chloride if it were in solution instead of the ionic soil.
These tests will not measure any surface ionic materials which
are not brought into solution because of insolubility, physical
entrapment or inadequate exposure to the extracting solvent.
Additionally, non-ionic components of the soil will not be mea-
sured.
1.3 Application
Caution should be exercised in comparing
results between different test equipment as well as the differ-
ent test methods. These methods are applicable as quality
control tools in evaluating the parameters of materials and
cleaning process, in terms of how they affect the final cleanli-
ness of the board or assembly. As process control tools, they
can be used to inspect printed wiring boards or printed wiring
assemblies and determine if they conform to the requirements
of the user’s performance specification. It is important to
understand, no calculation factor can exist to convert data
from one style of commercial tester to another due to the
great differences in system responses. See IPC-TR-583. This
means it is very difficult to compare data from different
machines. These procedures can also be used to assist
in-process development as general residue indicators, to
evaluate flux cleanability, solvent efficiency and general
improvements of process parameters.
Please note that this method does not predict reliabil-
ity and should ONLY be used as a process control tool.
2 Applicable Documents
An In-Depth Look at Ionic Cleanliness Testing
3 Test Specimen
Follow the equipment manufacturer’s
recommendations as to sample size. Recommended area cal-
culations for the unpopulated printed board and printed board
assembly are the following:
Printed Board Surface Area = Length x Width x 2
Printed Board Assembly Surface Area = (Length x Width x 2)
+ (1 x up to 50% of the board area)
Report the surface area used in the calculation and the per-
centage increased in calculating the surface area of a printed
board assembly.
There is no universally accepted method for determin-
ing the surface area of components. However, the determina-
tion of surface area for components should be established ini-
tially and used whenever that assembly style is being tested.
4 Manual Extraction Method
4.1 Description
This method describes the manual extrac-
tion of ionic material from the surface of a sample. This con-
sists of flushing the board surface with a stream of
2-propanol/DI water mixture and carefully capturing all of the
3000 Lakeside Drive, Suite 309S
Bannockburn, IL 60015-1249
IPC-TM-650
TEST METHODS MANUAL
Number
2.3.25
Subject
Detection and Measurement of Ionizable Surface
Contaminants by Resistivity of Solvent Extract (ROSE)
Date
11/12
Revision
D
Originating Task Group
Ionic Conductivity / Ion Chromatography Task Group
(5-32a)
Association
Connecting
Electronics
Industries
Note:
Note:
IPC-TR-583
Note:
Material
/n
this
Test
Methods
Manual
was
voluntarily
established
by
Technical
Committees
of
I
PC.
This
material
/s
advisory
only
and
"s
use
or
adaptation
，
s
entirely
voluntary.
IPC
disclaims
all
liability
of
any
kind
as
to
the
use,
application,
or
adaptation
of
this
material.
Users
are
also
wholly
responsible
for
protecting
themselves
against
all
claims
or
liabilities
for
patent
infringement.
Equipment
referenced
/s
for
the
convenience
of
the
user
and
does
not
imply
endorsement
by
IPC.
Page
1
of
5
extraction solution before measuring the resistivity of the com-
posite sample.
4.2 Test Equipment and Chemicals
4.2.1
Miscellaneous laboratory ware (e.g., beakers, funnels,
storage bottles and graduated cylinders). This plastic ware
can be high density polyethylene, polymethylpentene (poly-
pentene), polypropylene or equivalent. Glassware cannot be
used because it has been shown to contribute ionic contami-
nation in a short time with this 2-propanol/DI water solution.
4.2.2
Conductivity bridge or equivalent conductivity probe
and temperature compensated liquid conductivity cell appara-
tus capable of measuring specific resistivities within a range
covering at least 100 kΩ-cm to 20 MΩ-cm.
4.2.3
Deionization column. Up to 100% solvent compatible
mixed bed or equivalent.
Some of these columns are color dyed. This dye will
interfere with test results. Make certain that the column used
has no dye.
4.2.4
Electronic Grade 2-Propanol (isopropyl alcohol) or
99.5% purity minimum
4.2.5
Deionized water (DI water), preferably above 16
MΩ-cm water resistivity
It is critical to always use wash solution with the same
composition of 2-propanol/DI water for all comparative data
discussions.
4.2.6
Wash solution composed of 75 ± 2% v/v 2-propanol/
DI water or 50 ± 2% v/v 2-propanol/DI water. This wash solu-
tion must be deionized to a resistance equal to or greater than
16 MΩ-cm (conductivity less than 0.0625 µS/cm). If stored,
this wash solution must be freshly deionized prior to use. Typi-
cal resistivity of 25 MΩ-cm (conductivity of 0.04 µS/cm) can
be achieved. Measurement of the 2-propanol/DI water solu-
tion should be performed using a calibrated hydrometer. The
default extract solution composition is 75 ± 2% v/v
2-propanol/DI water.
4.3 Calibration of Bridge
This is essential in the manual
method because there can be no correlation between
resistivity/conductivity readings and NaCl equivalents without
calibration. All future specification requirements are to be
stated in maximum micrograms of NaCl equivalent per square
centimeter (µg NaCl Eq./cm
2
).
Ensure that a proper cell constant value is considered
in any conductivity calculations. Check the specific conductiv-
ity bridge manufacturer’s manual for this detail.
4.3.1
Prepare or purchase (these standard solutions are
available from equipment vendors, as well as many of the
chemical companies) a standard NaCl solution from a weight
of ACS reagent grade NaCl salt dissolved in deionized water
(16 MΩ-cm resistivity minimum) to produce a final diluted con-
centration of 0.06 g/liter NaCl (5 mL contains 300 µg NaCl).
It is recommended that dry NaCl be used for this solu-
tion. A recommended drying exposure is one hour at 105 °C
or higher.
4.3.2
Place one liter of the 2-propanol/DI water solution (at
the calibration temperature of the bridge in use) in a plastic
beaker.
The 75%/25% v/v or 50%/50% v/v 2-propanol/DI
water solution must be used in this calibration. Water cannot
be used since it is not the test solution used in the procedure.
The test solution used in this calibration should be made fresh
daily.
4.3.3
From a 50 mL burette, add to the liter of test solution,
5 mL of the standard 0.06 g/liter NaCl solution. Stir and mea-
sure resistivity/conductivity.
If the resistivity is measured, convert to conductivity by
take the reciprocal, prior to plotting the data.
4.3.4
From a 50 mL burette, add to the liter of test solution,
20 additional mL of the standard 0.06 g/liter NaCl solution, for
a total of 25 mL. Stir and measure resistivity/conductivity.
4.3.5
From a 50 mL burette, add to the liter of test solution,
25 additional mL of the standard 0.06 g/liter NaCl solution, for
a total of 50 mL. Stir and measure resistivity/conductivity.
4.3.6
Plot a three-point nomogram of Conductivity vs.
µg/liter of NaCl. A linear relationship is expected with the use
of a linear regression best fit line through the data points. If a
multi-range meter is used the curve should not be extended
beyond the maximum reading of the meter for that range,
unless linearity is proven by additional points obtained by add-
ing more standard salt solution. The nomogram will never
cross the zero point of conductivity.
An R
2
value of 0.99 should be expected before the
instrument would be considered calibrated.
Number
2.3.25
Subject
Detection and Measurement of Ionizable Surface Contaminants by
Resistivity of Solvent Extract (ROSE)
Date
11/12
Revision
D
IPC-TM-650
—
Note:
Note:
Note:
Note:
Note:
Note:
Note:
Page
2
of
5