IPC-TM-650 EN 2022 试验方法.pdf - 第373页

1.0 Scope This test method establishes a procedure for determining the in-plane coefficient of linear thermal expan- sion of organic films from 0-200°C using thermal mechanical analysis (TMA). 2.0 Applicable Documents AS…

required.

Decrease the temperature to –55 °C ± 2 °C [–67 °F

± 3 °F] or other temperature designated and allow to stabilize

for 10 minutes or until no further changes are noted on the

meter. Increase the temperatures to 25 °C [77 °F] at the same

rate and allow the specimens to stabilize.

5.6.3

Throughout

the thermal cycle, the temperature and

change in resistance as noted on the meter(strain) should be

recorded at the desired time and temperature (two minute

intervals).

5.7

Calculation of CTE

Plot

the gage resistance versus

the temperature. Measure the slope of the line between the

temperatures of interest and record.

The equation for calculating the Coefficient of Thermal Expan-

sion, ∝, are:

∝ = ∆R/R(GF)∆T

Where ∝ = the coefficient of thermal expansion R = gage

resistance reading

∆R = the change in resistance reading

∆T = the change in temperature

GF = the Gage Factor of a particular gage and gage con-

figuration and is furnished by the strain gagemanufacturer.

The GF for the WK gage is near 2.1

Example:

Resistance reading at 20 °C [68 °F] = 352.39

Resistance reading at 170 °C [338 °F] = 353.40

GF as furnished by manufacturer = 2.11

∝ =

(353.40 – 352.39)

(353.40

X 2.11 X 150)

= 9.03 ppm/°C

Note:

The

graph plot of ∆R/∆T will allow selection of any tem-

perature point.

All strain and temperature data should be recorded on a disk.

Software packages are available that the raw data (resistance

changes and temperature) to strain and temperature. The

software compensates for gage factor with temperature,

apparent strain of the gage, and the bridge configuration in

reducing the data. The software also uses the data from the

titanium silicate standard to adjust the reduced data of the

test specimen.

6 Notes

6.1

Suggested Sources of Materials

6.1.1

Source

of Adhesive System

Micro-Measurements Division

Measurements Group Inc.

P. O. Box 27777

Raleigh, NC 27611

Phone: (919) 365-3800

6.1.2 Information Bulletin

Micro-Measurements Division

Measurement Group Inc.

P.O. Box 27777

Raleigh, NC 27611

Phone (919) 365-3800

Bulletin # B130-10

6.1.3

Titanium

Silicate Standard

Corning Glass works

Corning, NY 14831

Micro-Measurements Division

Measurement Group Inc.

P.O. Box 27777

Raleigh, NC 27611

Phone (919) 365-3800

IPC-24412-2

Figure

2 Wheatstone Bridge Instrumentation Hookup

R Gage on Unknown

R Gage on Standard

R Standard Resistors on Instrument

M Direct Reading Strain Meter

External or Measurement

Half Bridge

Internal or Instrument

Half Bridge

IPC-TM-650

Number

2.4.41.2

Subject

Coefficient

of Thermal Expansion—Strain Gage Method

Date

05/04

Revision

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1.0

Scope

This test method establishes a procedure for

determining the in-plane coefficient of linear thermal expan-

sion of organic films from 0-200°C using thermal mechanical

analysis (TMA).

2.0

Applicable Documents

ASTM D 618

Standard

Practice for Conditioning Plastics

and Electrical Insulating Materials for Testing

ASTM

D 3386

Standard

Test Method for Coefficient of Lin-

ear Thermal Expansion of Electrical Insulating Materials

3.0

Test Specimen

The

test specimen shall consist of a

strip 15-20 mm long and 2 mm wide with a minimum thick-

ness of 10 µm and maximum thickness of 200 µm.

4.0

Apparatus or Material

Perkin-Elmer

TMA-7 with a film

fixture in extension mode or equivalent equipment capable of

handling films less than 25 µm thick.

5.0

Procedure

5.1

The

test specimens should be conditioned at 23 ± 2°C

and 50 ± 5% relative humidity for not less than 24 hours prior

to testing. Refer to ASTM D 618.

5.2

the manufacturer’s recommendations for equip-

ment startup and calibration.

5.2

Mount

the test specimen in the film holder. The sample

length (between the grips) should be between 11-13 mm.

Refer to ASTM D 3386.

5.3

Set

the force at 30 mN.

5.4

Perform

a prescan by heating a rate of 20°C/min. Under

inert atmosphere from −10°C to either 10°C above the mate-

rial glass transition temperature, T

or 10°C below the mate-

rial decomposition limit, T

max

determined using nitrogen. T

may

be determined using IPC Test Methods 2.4.24.2,

2.4.24.3, or 2.4.25.

5.5

Hold

the temperature for 60 min.

5.6 Cool

at a rate of 5°C/min to −10°C.

5.7

Hold

the temperature for 10 min.

5.8

Reheat

the specimen at a rate of 5°C/min to a maximum

temperature of 25°C below the glass transition temperature of

the polymer or 10°C below the material decomposition limit,

max

determined under nitrogen. Ar least two temperature

scans of the test specimen should be conducted without dis-

turbing the specimen in the TMA to confirm repeatability of

observed test results.

5.9

Calculate

the average coefficient of thermal expansion,

over the temperature intervals of interest as follows:

α =(∆L/∆T)/L

where L is the length of the test specimen between the grips,

∆L is the change in the length of the specimen (in the same

units) over the temperature interval ∆T, and ∆T is the tempera-

ture interval (normally 200°C) as illustrated in Figure 1. The

units are°C

-1

5.10 The

coefficient of linear thermal expansion from 0

200°C (below the glass transition) is

α=

(Length B − Length A)

(Length

A)(Temperature B − Temperature A)

2.4.41.2-01

Figure

emperature (°C)

200

Extension

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.4.41.3

Subject

In-Plane

Coefficient of Thermal Expansion, Organic

Films

Date

7/95

Revision

Originating Task Group

Deposited Dielectric Task Group (C-13a)

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.

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5.11

some instruments ∆L and ∆T may be read directly

from the recorder chart. On other instruments, constant fac-

tors (from the instrument calibration - see section 6.3) may

need to be applied to the chart readings to obtain these val-

ues.

6.0 Notes

6.1

Calibration

of the instrument must be carried out

according to the manufacturer’s recommendations. Two cali-

brations are required, one to establish the baseline and the

other to calibrate the TMA relative to a standard.

6.2

quartz specimen of 11-13 mm in length (between the

grips) is run at 5°C/min under inert gas purge (He) from −20

to 400°C to establish a baseline. The baseline is used to elimi-

nate the effects of grip expansion on extension measure-

ments. The coefficient of average thermal expansion of quartz

is 0.57 x 10

-6

/°C

(16-500°C)

This baseline procedure should

be used to either correct the instrument performance to

obtain the literature stated value of linear thermal expansion

quartz, or, in the event the instrument cannot be adjusted to

obtain this value, obtain an estimated correction factor which

is then applied to results from test specimens.

6.3

Using

a calibration standard with dimensions equivalent

to the test specimen, a calibration standard is run between

−10 and 200 °C and the observed coefficient of thermal

expansion is calculated using the expression:

=(∆L/∆T)/L

where L is the length of the test specimen between the grips.

∆L is the change in the length of the specimen (in the same

units) over the temperature interval ∆T, and ∆T is nominally

200 °C. The units of α

are

°C

−1

An estimated test specimen

correction factor, C, is then determined by dividing α

the

literature value, α

lit

for the standard(s). The estimated test

specimen correction factor is then as a multiplcation factor

and applied to the observed linear thermal expansion results

for the test specimens.

6.4

The

maximum temperature used in this test should be at

least 25°C below the glass transition temperature of the mate-

rial being studied. Heating above the glass transition may alter

the morphology of the specimen (e.g., change the molecular

orientation) leading to erroneous results. For materials with

glass transitions below 250°C, the temperature range over

which the coefficient of linear thermal expansion was deter-

mined must be noted, e.g., 50 x 10

-6

/°C

(0-150°C).

Lange’s Handbook of Chemistry, 12th edition, J. A. Dean, ed., McGraw-Hill, New York (1979).

IPC-TM-650

Number

2.4.41.3

Subject

In-Plane

Coefficient of Thermal Expansion, Organic Films

Date

7/95

Revision

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