IPC-TM-650 EN 2022 试验方法.pdf - 第493页

Calibrations only last 24 hours, so calibration shall be per- formed within 24 hours of the measurement. See 6.1 for more calibration notes. 5.2 Set up the unit to sweep the target frequency ± 0.5% of the target. 5.3 Mea…

Scope

This

procedure outlines a test method to deter-

mine the permittivity (dielectric constant or E’r) and loss tan-

gent (dissipation factor or Tanδ) of printed wiring materials at

various frequencies (from 1 MHz to 1.5 GHz) using a single

test fixture for the measurement.

The permittivity and loss tangent are measured using a narrow

sweep of frequency around the target or desired frequency.

The test method is built around the capability of currently

available materials analyzers, which use a capacitance

method to determine permittivity.

This test method is not intended for low loss materials, such

materials may be tested at fixed frequencies using other IPC

test methods.

Applicable Documents

HP 4291A-5 Product Note

‘‘Dielectric

Constant Evaluation

of Rough Surface Materials,’’ which describes how to make

accurate measurements using the HP 4291A and HP

16453A.

Application Note 380-1

‘‘Dielectric

Constant Measure-

ments of Solid Materials,’’ which contains a technical back-

ground, suitable for this subject.

Test Specimen

3.1

Each

specimen shall be 50 mm x 50 mm by the thick-

ness of the substrate material. Within the limits of the test fix-

ture, the thicker the sample the less error in the measure-

ments. Multilayer samples can be used to increase the

thickness of the sample, but these cannot be simple stacked

layers; they must be physically bonded with no air gaps

between the layers. A target thickness would be 1.0 mm, but

both thinner and thicker samples will work.

3.2

Three

specimens are required for this test.

3.3

All

materials are affected by moisture, including all rein-

forced laminates and most films. Therefore, all samples shall

be conditioned at 23°C ± 2°C and 50% RH ± 5% RH for a

minimum of 24 hours prior to testing. However, if a sample

has recently been etched or exposed to excessive moisture, it

should be dried in an air-circulating oven for two hours at

105°C +5°C, -2°C prior to testing and conditioned at room

temperature as mentioned above.

3.4

Sample Surface Preparation

3.4.1

is preferred that the sample be patterned with a

conductive material in the shape and size of the test elec-

trode. This conductive material is preferably 100 angstroms of

vapor deposited copper. Other metals may be used. In all

cases, the conductor on the sample must make good electri-

cal contact with the fixture electrode. Such a conductive pat-

tern eliminates air gaps and other potential sample mounting

errors.

3.4.2

Bare

dielectric materials may be tested with this test

method. The fixture electrodes must be applied with some

level of force to ensure a gap-free contact area. Determining

the correct force setting may require some trial and error test-

ing for each type of sample (see 6.4).

Equipment/Apparatus

4.1

The

Hewlett-Packard Impedance Material Analyzer,

model 4291A, or equivalent is recommended.

4.2 Hewlett-Packard

model number 16453A test fixture, or

equivalent

4.3

appropriate calibration-verification kit and a fixture-

correction kit as recommended in the instrument’s manual

(i.e., HP4291A Calibration kit). Such a kit usually includes the

following devices:

• OPEN and SHORT for fixture correction

• 50 Ohms impedance

• Dielectric (PTFE) of known characteristic for the purpose of

the calibration verification

4.4

Micrometer,

capable of 0.001 mm resolution

4.5

Circulating

oven capable of 105°C +5°C, -2°C

Procedure

5.1

Calibrate

the instrument using the calibration kit accord-

ing to the recommendations of the instrument manufacturer.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.5.9

Subject

Permittivity

and Loss Tangent, Parallel Plate,

1 MHz to 1.5 GHz

Date

11/98

Revision

Originating Task Group

HDI Test Methods Task Group (D-42a)

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.

age1of5

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ

Calibrations

only last 24 hours, so calibration shall be per-

formed within 24 hours of the measurement. See 6.1 for more

calibration notes.

5.2 Set up the unit to sweep the target frequency ± 0.5% of

the target.

5.3

Measure

the sample thickness with the micrometer and

insert into the test fixture. The sample must make good con-

tact with the fixture electrodes (see 6.1 concerning the proper

force to be applied). The sample must not touch the back wall

of the fixture. The sample electrode placement and thickness

measurement shall be obtained from the same area of the

sample.

5.4

Run

the test and record the average permittivity and loss

over the narrow frequency range sweep. The scanned data

may also be saved on disk. See 6.2 for comments on

expected behavior for permittivity as a function of frequency.

5.5

Repeat

5.1 through 5.4 for all desired frequencies.

5.6

Report

the average permittivity and loss at the frequen-

cies requested.

6 Notes

6.1

Correct

calibration and operation of the test equipment

is required to obtain accurate measurement of permittivity and

loss. Proper sample preparation is also very important for

obtaining useful data from this test. Calibrate the materials

analyzer in accordance with manufacturer’s instructions. An

automatic program has been developed for the HP 4291A,

which will ease calibration and setup (see 6.6).

6.2

The

permittivity should decrease slightly with increasing

frequency. If it increases greatly or decreases more than 0.2

units from approximately 20 MHz to 1.2 GHZ, reposition

(reset) the sample in the fixture and measure again (check for

debris between the electrodes; blow out with air).

6.3

Testing

at temperatures and humidities other than room

temperature may be performed with this instrument, as a spe-

cialized fixture can be placed in a temperature chamber. A

temperature chamber must be used when testing with this

fixture under conditions where condensation might contami-

nate the electrodes, as such contamination gives spurious

results.

6.4

The

pressure of the test fixture on the specimen affects

the measured permittivity and loss values, in particular for

un-metallized test specimens. Too light of pressure reduces

the area of electrode/sample contact, thus leaving air gaps,

which result in erroneous measurements. If the pressure is too

high, the sample can be reduced in thickness and the mea-

sured values would be incorrect because the thickness is

unknown. Making measurements while adjusting the force

should lead the operator to a force setting where the mea-

sured value is independent of the force applied.

6.5

The

HP 4291 Materials Analyzer and related fixtures and

calibration kits are available from Hewlett Packard, (800) 452-

4844.

6.6

Reference Program for Automatic Calibration and

Operation

This

automatic calibration and operation pro-

gram was developed for the HP 4291A and is published in

this method as a reference. Although the program listed in this

section has been tested and used, it is given here for ‘‘refer-

ence only.’’

6.6.1

Procedure Using Automatic Program

Turn

on the

analyzer with the program/calibration disk in the drive and fol-

low the user friendly calibration instructions, which appear on

the monitor. The calibration on the HP4291 lasts about 24

hours; after that, it begins to drift and provides slightly higher

values as a function of time. The calibration procedure in

6.6.1.1 through 6.6.1.10 should therefore be performed, at a

minimum, on a daily basis. During the calibration procedure,

the line traces on the monitor should be observed during each

step. Noisy or erratic traces are an indication of external inter-

ference. If noise is observed, the calibration procedure should

be aborted and rerun. Clean the electrode on the test head,

standards, and fixture connections and electrodes on a regu-

lar (weekly) basis. Blow dry.

6.6.1.1

Allow

at least 30 minutes for the unit to warm up

and stabilize.

6.6.1.2

the unit is a frequency sweeping unit, enter the

start and stop frequency (in megahertz) of the test (single fre-

quency tests use close start/stop frequencies, which should

be ± 0.5% of the target frequency).

6.6.1.3 Place

the OS (open) calibration standard on the test

head as prompted on the unit’s monitor and press Return on

the unit’s keyboard or ‘‘x1’’ on the unit.

IPC-TM-650

Number

2.5.5.9

Subject

Permittivity

and Loss Tangent, Parallel Plate,

1 MHz to 1.5 GHz

Date

11/98

Revision

age2of5

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ

6.6.1.4

Place

the 0Ω (short) calibration standard on the test

head as prompted on the unit’s monitor and press Return on

the unit’s keyboard or ‘‘x1’’ on the unit.

6.6.1.5

Place

the 50Ω calibration standard on the test head

as prompted on the unit’s monitor and press Return on the

unit’s keyboard or ‘‘x1’’ on the unit.

6.6.1.6 Place

the HP 16453A test fixture or equivalent on

the test head as specified in accordance with the manufactur-

er’s instructions as prompted on the unit’s monitor.

6.6.1.7 Open

the fixture gap and lock it open as prompted

on the monitor and press Return on the unit’s keyboard or

‘‘x1’’ on the unit.

6.6.1.8

Short

the fixture gap as prompted on the monitor

and press Return on the unit’s keyboard or ‘‘x1’’ on the unit.

6.6.1.9

Place

the pure PTFE specimen in the fixture in close

contact with electrodes and with the PTFE specimen not

touching the back wall of the fixture, then press Return on the

unit’s keyboard or ‘‘x1’’ on the unit. Pull out the PTFE and

recheck. Permittivity should be within ± 0.01 or ± 0.02 units.

If not, recalibrate starting at ‘‘Fixture.’’ If it is still off, redo the

calibration from beginning.

6.6.1.10

Test

the sample in accordance with Section 5.

6.6.2

The

following calibration/test program is the latest ver-

sion of what was developed for the P H4291A. Using a text

editor (no embedded coding), enter this program on a DOS-

formatted disk and name it ‘‘AUTOST.’’ Place the disk in the

unit and turn it on (If you have any improvements PLEASE for-

ward them to the IPC): The program disk will calibrate and

configure the instrument’s screen. Two windows will appear.

The top window should be permittivity (E’r) and the bottom

window should be loss tangent (δ). Both windows should be

set to the frequency range entered in 6.3.1.2. If they are not,

return to 6.3.1 and repeat the process.

100 !**** PLEASE SET PTFE THICKNESS ON LINE 1610 AND

2600 ****

110 !**** PLEASE SET PTFE PERMITTIVITY ON LINE 2580

****

120 !**** PLEASE SET PTFE LOSS TANGENT ON LINE 2590

****

130 !****

200 !**** SAVE THIS PROGRAM ON A DOS FORMATTED

210 !**** DISK USING A TEXT EDITOR (LINES 100-5000

220 !**** NAME THE PROGRAM ‘‘AUTOST’’ WITH NO

EXTENSION

230 !**** PLACE DISK IN UNITS DRIVE AND TURN UNIT ON

240 !**** PROGRAM WILL AUTOMATICALLY RUN. TO

RESET

250 !**** UNIT FOR NEW FREQUENCY RANGE PRESS

‘‘STOP’’

260 !**** ON UNITS FACE THEN ‘‘START’’ ON UNITS FACE.

270 !**** IF YOU WANT TO RE-CALIBRATE ANSWER YES [1]

280 !**** WHEN PROMPTED

290 !****

1000 !**** INITIALIZE UNIT FOR TEST ***

1010 ASSIGN @Hp4291 TO 800

1020 Scode=8

1030 CLEAR @Hp4291

1040 ABORT Scode

1050 OUTPUT @Hp4291;‘‘DISP:ALL BST’’

1070 !

1100 !**** CALIBRATION STATE CHECKING ****

1110 OUTPUT @Hp4291;‘‘SENS:CORR1?’’

1120 ENTER @Hp4291;Stat

230 IF Stat THEN

1130 INPUT ‘‘RE-CALIBRATE NOW? [1] Yes; [0] No

[RETURN OR x1]’’,Ans$

1140 IF Ans$<>‘‘1’’ THEN GOTO Test_loop

1150 END IF

1160 !

1200 !**** SETTING UP START/STOP FREQUENCY ****

1210 INPUT ‘‘Enter Start Frequency in MHz, [RETURN OR

x1]’’,A

1220 B=A*1000000

1230 OUTPUT @Hp4291;‘‘SENS:FREQ:STAR ’’;B

1240 INPUT ‘‘Enter Finish Frequency in MHz, [RETURN OR

x1]’’,A

1250 B=A*1000000

1260 OUTPUT @Hp4291;‘‘SENS:FREQ:STOP ’’;B

1270 !

1300 !**** SETTING ENABLE REGISTER FOR SRQ ****

1310 OUTPUT @Hp4291;‘‘STAT:INST:ENAB 256’’

1320 OUTPUT @Hp4291;‘‘*SRE 4’’

1330 !

1400 !**** SETTING TRIGGER SOURCE INTERNAL, CON-

TINUOUS OFF ****

1410 OUTPUT @Hp4291;‘‘TRIG:SOUR INT’’

1420 OUTPUT @Hp4291;‘‘INIT:CONT OFF’’

1430 !

1500 !**** SETTING CAL MODE TO FIXED/USER ****

1510 OUTPUT @Hp4291;‘‘SENS:CORR1:COLL:FPO USER’’

1520 OUTPUT @Hp4291;‘‘SENS:CORR2:COLL:FPO USER’’

IPC-TM-650

Number

2.5.5.9

Subject

Permittivity

and Loss Tangent, Parallel Plate,

1 MHz to 1.5 GHz

Date

11/98

Revision

age3of5

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ