IPC-TM-650 EN 2022 试验方法.pdf - 第428页

5.3.2 Dissipation Factor The dissipation factor value is read directly from the digital display. 5.4 Report The report shall contain the following: 1. Measurement of effective thickness of specimens tested. 2. Capacitanc…

1.0

Scope

This

test method is to determine the dielectric

constant and dissipation factor of raw printed wiring board

material at 1 MHz.

2.0

Applicable Documents

None

3.0

Test Specimens

Each

specimen shall be 50.8 ± 0.076

mm [2.0 ± 0.003 in] in diameter by thickness of laminate or

substrate material. Remove copper of metal-clad specimens

by etching using standard commercial practices. At least

three specimens are required.

4.0

Equipment/Apparatus

4.1 Meter

1 MHz Digital LCR Meter, Hewlett Packard

Mdl 4271A or equivalent.

4.2

Test Fixture

Hewlett

Packard Mdl 16022A test fixture

or equivalent.

4.3

Specimen Holder

special specimen holder made as

shown in Figure 1. This holder is designed to be compatible

with the H/P test fixture, Mdl 16022A.

4.0

Procedure

5.1 Preparation

5.1.1

Prepare

the specimens as specified in paragraph 3.0.

5.1.2 Calculate

the effect thickness (inches) =

0.01942 x Mass

Density

Mass

= Measured weight in grams

Density = Grams per cubic cm (as per ASTM-D-792,

Method 1A)

5.1.3

Coat

both sides of specimens with one uniform coat-

ing of silver conductive paint.

5.1.4

Air-dry

the specimens until dry to touch, then oven-dry

at 50°±2°C for 1/2 hour and cool in a desiccator.

5.1.5

Punch

or machine a 25.4 mm [1.0 in] diameter disc

from the 50.8 mm [2.0 in] specimens. (Assure that there is no

carry over of the paint from one side to the other.)

5.1.6 Condition

the 25.4 mm [1.0 in] specimens for a mini-

mum of 40 hours at 23°±5°C at a relative humidity of 50%.

5.2

Testing

5.2.1

Turn

meter on and allow to warm up for 60 minutes

minimum.

5.2.1.1

Set

the controls on the meter as follows:

Function – C-D

Range – Manual

Trigger – Internal

Rate – FCW

Test Signal Level – Low

5.2.1.2

Connect

the cables for the test fixture to the appro-

priate connectors.

5.2.2

Plug

the special specimen holder into the test fixture.

5.2.3

The

digital display on the meter will show the capaci-

tance value and the dissipation factor of the unknown dielec-

tric specimen.

5.3

Calculation

5.3.1 Dielectric Constant

The

dielectric constant shall be

determined by using the following formula:

K =

0.225

K = Dielectric constant

C = Capacitance reading from Mdl 4271A Meter

A = Area of a 1-inch disc (square inches)

t = Effective thickness (inches)

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.5.2

Subject

Dielectric

Constant and Dissipation Factor of

Printed Wiring Board Material—Clip Method

Date

12/87

Revision

Originating Task Group

N/A

Material

in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only

and its use or adaptation is 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 is for the convenience of the user and does not imply endorsement by the IPC.

age1of2

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ

5.3.2

Dissipation Factor

The

dissipation factor value is

read directly from the digital display.

5.4

Report

The

report shall contain the following:

1. Measurement of effective thickness of specimens tested.

2. Capacitance values of the specimens tested.

3. Calculated dielectric constants and averaged measure-

ment.

4. Dissipation factor values and averaged measurement.

6.0 Notes

6.1

The

dielectric constant is defined as the ratio of the

capacitance with the test material between the two plates to

the capacitance of air between two plates.

6.2

The

dissipation factor of a dielectric material is the rela-

tionship between the permittivity (capacitance of material) and

conductivity (ability to conduct or the reciprocal of the electri-

cal resistivity) measured at a given frequency.

IPC-2552-1

Figure

1 Special Test Fixture for Dielectric Constant and Dissipation Factor Measurements

IPC-TM-650

Number

2.5.5.2

Subject

Dielectric

Constant and Dissipation Factor of Printed Wiring

Board Material—Clip Method

Date

12/87

Revision

age2of2

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ

1.0

Scope

1.1 Purpose

This

method is suitable for determining the

volume permittivity, (dielectric constant) and loss tangent (dis-

sipation factor) of insulating materials at 1 MHz. It is not

dependent on either direct or indirect measurement of speci-

men thickness and therefore is very useful for thin films and

laminates but may also be used on specimens up to approxi-

mately 6.35 mm [0.25 in] thick.

It is useful for all ranges of permittivity and for loss tangent as

low as 0.0005 providing the range and accuracy of the bridge

used are adequate.

1.2

Description of Method

The

two fluid method utilizes

air as one fluid and a suitable liquid, normally Dow 200 1.0CS

silicone fluid, as the second. Using an established value for

the permittivity of air, the values for the permittivity of the fluid

and the sample may easily be calculated. The cell spacing is

fixed during all readings but does not need to be known accu-

rately for the series of readings required. Since specimens do

not require any electrodes to be applied and since many

specimens can be measured at one time without changing

any spacings or machine settings, the method is not only very

accurate but very rapid.

The method has been used for measurement of PTFE and

epoxy glass laminates and flexible films, e.g., polyimide.

Reproducibility lab to lab is excellent for permittivity provided

minimal precautions are observed and bridge accuracy is

appropriate. On most materials, the effects of small changes

in moisture or temperature are larger than any error due to the

method. Lab to lab correlation on stable material such as

PTFE have shown results to be consistently within 0.005 or

(0.20%).

2.0

Applicable Document

3.0 Test Specimens

3.1 Number

Unless

otherwise specified in the material

specification, one specimen is adequate for materials which

are uniform, e.g., unreinforced plastics. For woven reinforced

materials where resin content may vary, at least 2 specimens,

representing the thinnest and thickest part of the sample,

should be tested. For material with random reinforcement, a

minimum of three specimens from the edge and center of the

sheet are recommended to characterize variation within the

sheet.

3.2

Form

Individual

specimens shall be 81.3 mm ± 1.3 mm

x 81.3 to 101.6 mm [3.2 in ± 0.05 in x 3.2 in to 4.0 in] x thick-

ness.

For materials under 0.254 mm [0.010 in], individual specimens

should be stacked to a minimum of 0.381 mm [0.015 in] to

maximize accuracy. Thinner specimen buildups may be used

if the correlation with the 0.381 mm [0.015 in] specimen is

within the required accuracy for the particular equipment, cell

spacing and material being tested.

3.3

Foil Clad Materials

All

foil clad materials shall have the

metal cladding completely removed by etching and shall be

rinsed and dried prior to conditioning.

3.4

Marking

Mark

each specimen in the upper left corner

with an engraving pencil or an ink which is not soluble in the

Dow Corning 200 fluid.

4.0

Apparatus/Materials

4.1

MHz Capacitance Bridge with 0-200 (or 0-100) pf

range.

4.2

Cell

Balsbaugh

LD-3

equivalent (see Figure 1) three

terminal cell. Note: For accuracy of 1% or better, room tem-

perature must not vary more than 1°C during measurements.

Temperature control is necessary if laboratory variation

exceeds these limits.

Capacitance Bridge—Suggested is Boonton 76A automatic capacitance bridge. This model has adequate capacitance range and adequate conductance resolu-

tion (0.001 microsiemen) to permit measurement of dissipation factors down to approximately 0.0005. Other bridges, e.g., Boonton 75D, are also adequate for

low loss materials and some other bridges may be suitable for higher loss materials, such as epoxy where dissipation factors exceed 0.01 and resolution of 0.01

microsiemen or even 0.1 microsiemen may be adequate.

2. Balsbaugh LD-3 Gillian and Co,, Watertown, MA, (617) 624-5688 or Zincast Corporation, 44 Homestead Ave., Stanford, CT 06902, (203) 359-0109

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.5.3

Subject

Permittivity

(Dielectric Constant) and Loss Tangent

(Dissipation Factor) of Materials (Two Fluid Cell

Method)

Date

12/87

Revision

Originating Task Group

N/A

Material

in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only

and its use or adaptation is 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 is for the convenience of the user and does not imply endorsement by the IPC.

age1of4

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ