IPC-TM-650 EN 2022 试验方法.pdf - 第324页

1 Scope This test is designed to determine the glass tran- sition temperature (T g ) and coefficient of thermal expansion (CTE) of dielectric materials used in high density interconnect (HDI) and microvias by the use of …

DSC

measures the heat capacity of a specimen, TMA mea-

sures the expansion of a specimen, and DMA measures the

stiffness of the specimen. The T

determined

from TMA, DSC,

and DMA may vary significantly (up to 20°C) because they are

measuring different physical properties, which change differ-

ently as the specimen goes through T

As a result, the test

equipment used should be noted after the reported T

value

(i.e., 136°C; DSC, TMA, or DMA).

6.3

Most

thermal analysis equipment have the software

capability to determine sample T

and

modulus values; it is

recommended that this approach be used for consistency.

6.4

Load Selection Criteria

The

initial load should be 5 g

of tension (approximately 50 mN). The load (or force) may be

adjusted for differences in material types or specimen configu-

ration in order to assure the specimen is being held without

slack. Avoid an excessive load (or force), which may result in

elongation of the specimen due to the applied tension. Speci-

mens above T

may

become so soft as to be stretched.

Examine all specimens after the test to look for signs of exces-

sive loads, distortions, tears, and other defects.

6.5

Thermal Stresses and Other Anomalies

DMA

results

may be affected by any stresses that might have been frozen

into the sample during processing. Samples showing anoma-

lous behavior should be run a second time or preconditioned

to remove such stresses. Holding the sample temperature at

20°C above the glass transition and holding for five minutes,

followed by slow cooling, will normally remove the stresses in

the sample.

6.6

Understanding DMA

Refer

to ASTM D-4092 for a bet-

ter understanding of concepts and definitions of terms for

dynamic mechanical measurements.

6.7

Instrument Suppliers

DMA

instruments capable of

meeting the requirements of this test method are known to be

available from:

TA Instruments

Perkin Elmer Corp.

Seiko Instruments, Inc.

Rheometrics Scientific

Netzsch Instruments, Inc.

IPC-TM-650

Number

2.4.24.4

Subject

Glass

Transition and Modulus of Materials Used in High Density

Interconnection (HDI) and Microvias - DMA Method

Date

11/98

Revision

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Scope

This

test is designed to determine the glass tran-

sition temperature (T

)

and coefficient of thermal expansion

(CTE) of dielectric materials used in high density interconnect

(HDI) and microvias by the use of thermal mechanical analysis

(TMA). For isotropic (unreinforced) materials, either method (A

= thick specimen; B = thin specimen) may be used. For aniso-

tropic materials (reinforced), both methods shall be used,

since the z axis expansion (Method A) is not the same as the

x-y axis expansion (Method B).

Applicable Documents

None

Test Specimens

3.1 Size

Method A

Volumetric

or Z-axis expansion – thick specimens

(>0.50 mm): Specimens shall be approximately 6.5 mm x 6.5

mm. The thickness shall be a minimum of 0.5 mm; for thick-

nesses <0.5 mm, use Method B. Exact specimen dimensions

may be determined by the apparatus used.

Method

In-plane

(x-y) expansion – thin specimens (<0.5

mm): Specimens shall be approximately 15 mm to 20 mm

long and 2 mm wide, with a minimum thickness of 10 µm and

a maximum thickness of 0.75 mm. Exact specimen dimen-

sions may be determined by the apparatus used.

3.2

All

specimens should be fully cured according to manu-

facturer’s recommendations. Thick specimens may be made

by use of multiple lamination/cure cycles if required.

3.3

For

Method B, two samples are to be measured, taken

at 90° to each other and labeled in the x and y directions. Iso-

tropic materials are anticipated to have the same CTE for x

and y, and reinforced materials are likely to have differing x

and y CTE.

Equipment/Apparatus

4.1

TMA capable of determination of dimensional change

to within 0.0025 mm over the specified temperature range.

Preferably the TMA will have computer data acquisition and

analysis. The TMA must have an environmental chamber

capable of having nitrogen flush gas and heating of the speci-

men to 310°C.

4.2

Diamond

blade or saw, sanding equipment, or equiva-

lent to provide specimens of the size and edge quality

required for Method A

4.3 Scissors

or razor blades or equivalent to provide speci-

mens of size and edge quality for Method B

4.4

Air

circulating oven capable of maintaining 105°C ± 2°C

4.5

Dessicator

capable of an atmosphere less than 30% RH

at 23°C

4.6

Etching

system capable of complete removal of metallic

cladding

Procedure

5.1.1

Metallic

clad specimens shall be tested without the

cladding. Etch and dry using appropriate procedures and

equipment.

5.1.2

Specimens

shall be cut to the specified size using

appropriate procedures and equipment to minimize thermal

shock and mechanical stress. Method A specimens shall have

their edges smooth and burr-free by means of sanding or

equivalent (to allow the specimen to rest flat on the mounting

stage). Method B specimens shall be rectangular, with their

long edges parallel (to ensure good mounting in the film fix-

ture). Method B specimens shall have smooth edges without

nicks or tears.

5.1.3

Specimens

shall be preconditioned by baking for one

hour ± 15 minutes at 105°C, then cooled to room temperature

in a dessicator.

5.2

Measurement

5.2.1 Apparatus Set-up

5.2.1.1 Install the Correct TMA Probe

Method A

Set

up the TMA with a non-penetrating quartz

expansion probe.

Method

Set

up the TMA with a thin film fixture/clamp.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.4.24.5

Subject

Glass

Transition Temperature and Thermal

Expansion of Materials Used in High Density

Interconnection (HDI) and Microvias - TMA Method

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.

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5.2.1.2

Apply the Load

Method A

Mount

the specimen on the stage of the TMA

and apply load at 5 g (see 6.5 for an explanation of load cri-

teria). Enclose the specimen and probe in the environmental

chamber.

Method

Mount

the specimen in the clamps of the film fix-

ture according to the manufacturer’s instructions and apply 2

g tension force (see 6.5 for an explanation of the load criteria).

Enclose the specimen and probe in the environmental cham-

ber.

5.2.1.3

Provide

an inert gas purge (helium or nitrogen) at a

rate of 30 ml/min to 150 ml/min to the environmental cham-

ber. Temperature calibration of the TMA must be performed

under the same gas conditions.

5.2.1.4

Measure

the inital specimen thickness (Method A) or

length (Method B) prior to each heat cycle (L

5.2.2

Many

specimens have built in thermal stresses from

the curing step, which relaxes during the specimen heating

during a TMA test. This relaxation results in TMA scans, which

make determination of T

and

CTE impossible (see Figure 1).

Two heat cycles are required to obtain valid T

and

CTE val-

ues.

5.2.3

Running the TMA Temperature Scan

5.2.3.1

Initial

Temperature (T

initial

)

For specimens with T

below

or near room temperature,

start the scan at least 20°C below the anticipated transi-

tion. This may require a TMA with refrigeration control of

the environmental chamber.

b. For specimens with T

greater

than room temperature,

start the scan at 30°C.

5.2.3.2

Temperature Rate

Depending

on sample prepa-

ration, two heating cycles may be required to obtain accurate

and

CTE above T

If the sample shows unexpected

shrinkage above T

(see

Figure 1), the two heat test method

is required. If the sample does not show anomalous behavior,

only one heat cycle (the second heat cycle at 5°C/min) is

required.

a. First heat: The first heat cycle of the specimen shall be run

at 10°C/min.

b. Second heat (reportable data heat cycle): The second

heat cycle of the specimen shall be run at 5°C/min.

5.2.3.3

Temperature Excursion

First heat: Continue heating the specimen to a tempera-

ture 20°C greater than the anticipated T

until the

anomalous thermal relaxation has stopped. See Figure 1

for an example of anomalous first heat behavior. Hold the

specimen at this temperature for a minimum of five min-

utes. Avoid holding the sample at this temperature for too

long; sample degradation might occur. Cool the specimen

to the initial temperature under temperature control at

5°C/min to 10°C/min. This should prevent reestablishment

of thermal stresses.

b. Second heat (reportable data heat cycle): The second

heat cycle of the specimen shall continue to 310°C (to

ensure good data at 300°C).

5.3

Evaluation

5.3.1

The

TMA expansion curve should resemble the plot

shown in Figure 2.

IPC-24245-1

Figure

1 TMA Expansion Curves: First Heat Cycle and

Second Heat Cycle

IPC-TM-650

Number

2.4.24.5

Subject

Glass

Transition Temperature and Thermal Expansion of

Materials Used in High Density Interconnection (HDI) and

Microvias - TMA Method

Date

11/98

Revision

age2of5

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