1.0Scope This test method is designed to determine vol-ume resistivity and surface resistivity of metallic-clad or unclad laminates under conditions of specified humidity and tempera-ture and at elevated temperatures.
2.0Applicable Documents
ASTM-D-257D-C Resistance or Conductance of Insulating Materials
IPC-TM-650
Method2.3.6,Etching,Ammonium Persulfate
Method,2.3.7Etching,Ferric Chloride
Method2.3.7.1,Cupric Chloride Etching
Method 2.6.3,Moisture and Insulation Resistance,Rigid, Rigid/Flex and Flex Printed Wiring Boards
3.0Test Specimens
3.1Laminate thickness of0.51mm[0.020in]or greater. Three specimens of dimensions101.6±3.2mm x10
1.6±3.2mm[
4.0±0.125in x4.0±0.125in]by thickness shall be prepared for each test condition,unless otherwi specified.
3.2Laminate thickness of less than0.51mm[0.020in]. Three specimens of dimensions50.8±1.6mm x50.8±1.6 mm[2.0±0.062x2.0±0.062in]by the thickness shall be prepared for each test condition,unless otherwi specified.
4.0Equipment Apparatus
4.1Conditioning chamber capable of maintaining35±2°C [95±3.6°F]and90+5,–0%relative humidity.
4.2Conditioning chamber capable of attaining the tempera-ture and humidity conditions specified in IPC-TM-650,Method 2.6.3.
4.3Air circulating oven capable of maintaining the specified test temperatures to within±2°C[±3.6°F].
4.4Resistance measuring instrumentation capable of mea-suring to1012meg-ohms,minimum,with an accuracy of±5 percent at its highest scale tting.The equipment shall have the capability of applying
500volts dc to the test specimen.4.5A system/fixture for electrical connections into the tem-perature and humidity chambers(e4.1,4.2,4.3).Three parate cables shall be provided to make connections to each specimen being conditioned/tested.The center conduc-tor of each cable shall be connected to one of the three elec-trodes applied to the test specimen.The opposite ends of the cables shall be brought outside the chamber and terminated at a convenient location for connection to the measuring instrument.Shields shall be trimmed back from the ends of the center conductor insulation and interconnected to the guard post of the measuring instrument.See6.2for additional information.
Support the specimen parallel to the air flow through the chamber during conditioning.
Special care should be taken to ensure that materials ud in the fixture are such that resistance readings are that of the material being tested and not the fixture.
4.6A measurement device capable of measuring laminate thickness to the nearest0.0025mm[0.0001in].
4.7Material and apparatus for formation of specimen con-ductors.
4.7.1Conductor silver paint;composition4817by Dupont Company,or equivalent.
con
4.7.2A system for applying the paint to the specimen,such as silk screening.
4.7.3A mask,fixture,photoprinting system,or equivalent, for applying the applicable electrodes/test pattern to the specimen(See Dimension Table).
4.8Etching system in accordance with IPC-TM-650, Method2.3.6,2.3.7,or2.3.7.1.
5.0Procedure
5.1Specimen Preparation
5.1.1Test patterns with the applicable dimensions shown in the Dimension Table,and in accordance with Figures1,2, and3shall be generated,as follows:
The Institute for Interconnecting and Packaging Electronic Circuits 2215Sanders Road•Northbrook,IL60062
IPC-TM-650
TEST METHODS MANUAL Number
2.5.17.1
Subject
Volume and Surface Resistivity of Dielectric Materials
Date
12/94
Revision
A
Originating Task Group
MIL-P-13949Test Methods Task Group(7-11b)
Material in this Test Methods Manual was voluntarily established by Technical Committees of the IPC.This material is advisory only
and its u or adaptation is entirely voluntary.IPC disclaims all liability of any kind as to the u,application,or adaptation of this
material.Urs are also wholly responsible for protecting themlves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the ur and does not imply endorment by the IPC.
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5.1.1.1Metallic-clad materials having a thickness of less than0.51mm[0.020in]shall be photoprinted with a pattern of the outline of the conductors and etched in accordance with IPC-TM-650,Methods2.3.6,2.3.7,or2.3.7.1.The elec-trodes shall then be completed(filled in)using silver conduc-tive paint.
5.1.1.2Metallic-clad laminates0.51mm[0.020in]or thicker shall be etched in accordance with IPC-TM-650,Method 2.3.6,2.3.7,or2.3.7.1.A pattern of the outline of the conduc-tors may be photoprinted before etching.Test electrodes shall be applied using silver conductive paint and an appropriate test pattern application system.
5.1.1.3Solid metal foil electrodes shall not be acceptable in any ca,except for the outer electrode for laminates less than0.51mm[0.020in].A small pad of retained cladding may be retained within the electrode borders to facilitate soldering of leads.
大学英语四级考试网5.1.2If soldering techniques are ud to attach leads,suit-able cleaning procedures shall be ud to remove flux and other residue.
5.2Conditioning
5.2.1Humidity Conditioning
5.2.1.1Specimens of a thickness less than0.51mm[0.020 in]shall be subjected to90+5-0%relative humidity and35±2°C[95±3.6°F]for a period of96+2,-0hours prior to elec-trical measurement.5.2.1.2Specimens of a thickness greater than,or equal to, 0.51mm[0.020in]shall be subjected to the conditioning specified in IPC-TM-650,Method2.
6.3,paragraph5.1.3.Fol-lowing the tenth cycle,the conditioning chamber shall main-tain a temperature of25±2°C[77±3.6°F]and90+5,0% relative humidity during the interval that electrical measure-ments are being made.
5.2.2At Elevated Temperature Conditioning Speci-mens shall be subjected to the specified temperature(bad on material type and specification requirements)for a period of24hours-0,+2hours.Unless otherwi specified,the tem-perature shall be125±2°C[257±3.6°F].
5.3Electrical Measurements All electrical measurements shall be made inside the applicable conditioning chamber and at the conditions specified in5.2.
5.3.1Electrical measurements taken on specimens condi-tioned in accordance with paragraph5.2.1shall be completed within the2hour tolerance of the conditioning.
5.3.2Electrical measurements taken on specimens condi-tioned in accordance with paragraph5.2.2shall be made after achieving1.5hours steady state of25±2°C[77±3.6°F]and 90+5,-0%relative humidity.All measurements shall be com-pleted within2hours.
5.3.3Electrical measurements taken on specimens condi-tioned in accordance with paragraph5.3shall be completed within the2hour tolerance of the conditioning.
Dimension Table
Ba Thickness D
1Diameter D
2上海市市花
Diameter D
3
Diameter D
4
D
5
A(cm2)P/D
4
Less than
0.51mm (0.020inches)
1.000
(2.540)
1.020
(2.591)
1.375
(3.493)
0.010
(0.025)
0.177
(0.460)
5.169317.4kaven
±0.005
(0.013)
±0.005
(0.013)
±0.005
(0.013)
±0.001
(0.003)
±0.005
(0.013)
0.51mm (0.020inches) and greater
2.000
多谢粤语(5.080)
2.500
(6.350)
3.000
(7.520)
0.250
(0.636)
0.250
(0.636)
25.65228.27
±0.015
(0.038)
雕镂±0.015
(0.038)
±0.015
longkou(0.038)
±0.005
(0.038)
±0.015
(0.038)
For the above:Do=(D
1+D
2
)/2
A=πDo2
4
P=πD
O
Note:Dimensions are in inches with metric equivalents in parenthesis(1inch=2.54cm).
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5.3.4
All electrical measurements shall be made using 500
volts direct current.The voltage shall be applied to the speci-men for 60+5,-0conds prior to taking the actual reading,for stabilization purpos.
5.3.5
Measure the volume resistance by connecting the
resistance measuring device to the specimen electrodes through the fixture system as described in 4.5in accordance with Figure 2.
5.3.6
Measure the surface resistance by interchanging the
test cables connecting the solid back electrode and the outer ring to the instrument for the arrangement shown in Figure 3.
落实英文5.4Specimen Thickness
Each specimen shall be mea-sured for its thickness without cladding.Specimens for each test condition shall have their thickness readings
averaged.
Figure 1Test pattern dimensions (See
table)Figure
2
Figure 3
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英语书5.5Calculations
5.5.1The volume resistivity shall be calculated as follows:
r=RA
T
Where:
r=Volume resistivity in megohm-centimeters
R=Measured volume resistance in megohms
A=Effective area of the guarded electrode in square centi-meters
T=Average thickness of specimen in centimeters
T=(t)x2.54[e5.2.1]
t=Average thickness(t)in inches(from5.4)
Note:The value of A may be obtained from the Dimension Table.
5.5.2The surface resistivity shall be calculated as follows:
r1=R1P
D4
Where:
r1=Surface resistivity in megohms
R1=Measured surface resistance in megohms
P=Effective perimeter of the guarded electrode in centime-ters
D4=Width of the test gap in centimeters
Note:The ratio of P/D4for the electrode configuration being ud may be obtained from the Dimension Table included in Figure1.5.6Reporting
5.6.1The volume resistivity of each specimen and the aver-age shall be reported.Each condition tested shall be reported parately.
5.6.2The surface resistivity of each specimen and the aver-age shall be reported.Each condition shall be reported pa-rately.
5.6.2.1The surface resistance is the direct reading of the megohmeter scale and should be recorded in megohms.
6.0Notes
6.1For additional information e ASTM-D-257,D-C Resis-tance or Conductance of Insulating Materials.
6.2The system of electrical connections to the specimens may benefit from a coaxial cable t-up designed to shield the measurement of volume or surface resistances from electrical interference.
6.3Performance Specifications The following informa-tion should be reviewed within the applicable performance specification or product procurement document:
a.Specimen size,quantity,and configuration,if other thanafraid怎么读
that specified in3.0.
b.Conditioning parameters,such as temperature for Elevated
Temperatures.
c.Any other changes to the specified procedures in this
method.
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