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SEMI G52-90 © SEMI 1990, 2004 3 10.2.2 Place the bags in the water bath at T > 95°C for 30 ± 2 m inutes. 10.2.3 Remove the bags f rom the bath a nd allow to reach room temperature. 10.2.4 The lead frames, which are in…

SEMI G52-90 © SEMI 1990, 2004 2

6.8 Borosilicate Glass flasks and Pipettes for Anion

Standard Solutions — 100, 250, 500, and 100 ml

capacity (flasks); 1, 10, and 25 ml capacity (pipettes).

6.9 Chemical Balance, Weighing Chemicals

6.10 Scissors, Tweezers, Spatula

7 Reagents and Materials

7.1 Deionized water, resistivity  15 megohm

centimeters at 25°C per ASTM D 1193.

7.2 Eluents and regenerants for specific chromatograph

columns prepared per chromatograph equipment

manufacturer’s recommendations so that the water peak

can be separated from the ionic peaks.

7.3 Compounds for Cation Standard Solutions —

NaCl, NH

Cl, KC1.

7.3.1 Compounds for Anion Standard Solutions —

NaCl, Na

HPO

, 12H

O, NaBr, NaNO

, K

NOTE 3: All compounds are to be reagent grade.

8 Sampling

8.1 The leadframes must not be touched, except with

previously cleaned tweezers or double-layered cotton

gloves with polyethylene outer gloves in order to avoid

additional contamination.

8.2 The sample size (i.e., the number of frames to be

tested in this destructive test) may be determined by

agreement between the customer and the vendor. The

recommended sample sizes are 10–50 cm

for testing

pads and 200–500 cm for the test of overall leadframes.

NOTE 4: The surface area of the frame is calculated from the

leadframe drawing, and includes the top, bottom and side

surfaces. It is important that user and supplier agree on the

surface area calculation for any given leadframe

configuration.

9 Preparation of Standard — Solutions and

Chromatograph Calibration

9.1 Standard Solutions

9.1.1 The single-ingredient standard solutions of each

ion (Na

, NH

, K

; C1



, No

, Br

, SO

2

, PO

3

) are

made by dissolving 1.000 g of each ion into 1.000 liter

of D.I. water, respectively. The stored multi-ingredient

standard solutions shown in Table 2 are then made form

these single-ingredient standard solutions by the

dilution method.

9.1.2 Cation and anion standard solutions for

calibration are made by diluting the stored multi-

ingredient standard solutions as shown in Table 2.

9.1.3 Store the multi-ingredient standard solution and

the calibration solutions in the correct flasks and label

with the ion type and concentration.

NOTE 5: New standard solutions for calibration are required

every 24 hours. Ensure that the flasks are cleaned with water

before refilling with a new solution.

9.2 Calibration

9.2.1 Set up the chromatograph and regenerate the

columns according to the manufacturer’s instructions

(ASTM D 4327 provides further details).

9.2.2 Run the eluent through the chromatograph until a

stable baseline chromatograph is obtained.

9.2.3 Select the infection volume recommended by the

manufacturer for each ion type and inject in to the

chromatograph. Record the chromatograph for each ion

type (see Figure 1), and make the calibration curve for

each ion (ion concentration versus peak height or area).

NOTE 6: Peak height or area under the ion’s characteristic

curve is proportional to the concentration.

10 Procedure — Bag Extraction Method

10.1 Preparation of Extraction Bags

10.1.1 Add 100 ml of DI water to the

polypropylene/polyethylene double layered bag and

seal them with the hot bar bag sealer. The amount of air

in the bags should be reduced as much as possible

before sealing.

NOTE 7: Two bags are required for each test and must come

from the same manufacturing lot.

10.1.2 Place the bags in the water bath at T > 95°C for

2 hours ± 5 minutes.

10.1.3 Allow the bags to reach room temperature but

leave sealed until ready for use at which time open the

bags (use clean scissors for the bags) and rinse out five

(5) times with DI water.

10.2 Extraction Process

10.2.1 Place the samples in the bags. Cover the frames

with a known volume of water (e.g., 100 ml and then

seal the bags). Also, place a similar amount of water in

an empty bag and seal.

NOTE 8: The amount of air in the bags should be reduced as

much as possible before sealing. The bags that only contain

water provide the background contamination of the bag. Do

not select the frames or remove them from their shipping

container until ready to test the surface contamination. The

recommended volume of water is 10–30 ml for the testing die

pads only and 100 ml for testing complete leadframes. Lead

frames should be bent after sealing so that the water is in

contact with all surfaces.

SEMI G52-90 © SEMI 1990, 2004 3

10.2.2 Place the bags in the water bath at T > 95°C for

30 ± 2 minutes.

10.2.3 Remove the bags from the bath and allow to

reach room temperature.

10.2.4 The lead frames, which are inside the sealed

bags, are moved to one side of the bags without

opening the bags. Then the solution is separated from

leadframes by sealing the mean portion of the bags

without opening.

11 Procedure — Container Extraction Method

NOTE 9: The size of the containers to be used depends on

the expected volume of water and the leadframes. The

container must be at least three-quarters filled with the water

and leadframes.

11.1 Preparation of Extraction Vessels

11.1.1 Fill the containers with DI water and attach the

caps. In order to reduce the amount of air in the vessel,

fill vessels to the amount of three-quarter.

NOTE 10: Two containers are required for each test and must

come from the same manufacturing batch.

11.1.2 Place the containers in the water bath at T >

95°C for 2 hours ± 5 minutes.

11.1.3 Remove the containers from the bath and rinse

out five (5) times with DI water.

11.2 Process

11.2.1 Place the samples in one of the containers

cleaned per Section 11.1.1.

NOTE 11: Leadframes may be cut or rolled in order to ease

loading to the container. Die pads may be tested separately, if

desired, by cutting from the leadframes.

11.2.1.1 Add the required volume of DI water and cap

the container. Place a similar amount of water into the

other cleaned container and attach the cap.

NOTE 12: Do not select the frames or remove them from

their shipping container until ready to test for the surface

contamination. Recommended volumes of water are 10–30 ml

for testing die pads only and 100 ml for the entire leadframe

— samples must be covered by water.

11.2.2 Place the containers in the water bath at T >

95°C for 30 ± 2 minutes.

11.2.3 Remove the containers from the bath and allow

to reach room temperature.

11.2.4 Remove the leadframes from the container and

cap it again.

12 Measurements

12.1 Prepare the chromatograph for operation by

regenerating the columns according to the

manufacturer’s recommendations.

12.2 Run the eluent through the chromatograph until a

stable baseline calibration is established.

12.3 Inject the recommended sample size of test

solution into the chromatograph and record the ion

chromatogram.

12.4 Repeat for all the samples and also run the

background sample.

NOTE 13: The time from extraction to insertion of sample is

to be within eight hours.

12.5 Sample concentrations are determined from the

calibration curves for each ion type.

12.6 The surface concentration of ionic contaminants

for each ion type (SCIC) is given by the following

equation:

SCIC (ng/cm

) =

(Sample conc. – Background conc.)



Extraction Volume (mL)

Leadframe Surface Area (cm

)



No. of Leadframes

NOTE 14: Allowable concentration levels are to be agreed

between the user and supplier.

Table 1 Sensitivity of Ion Chromatograph

Ion Sensitivity (ng/ml)

0.2

0.5

Cation

1.0



0.3

3

2.0

1.0

Anion

1.0

Table 2 Concentration of Standard Solution for

Calibration

Mixed Standard

Solution (ug/ml)

Standard Solution for

Calibration(ng/ml)

Ion I II III

Cation Na

10 5 10 20

Anion Cl



4 10 20 40

3

10 25 50 100



4 10 20 40



4 10 20 40

2

4 10 20 40

Retention Time (Min.)

Cation

Retention Time (Min.)

nion

–

Figure 1

Schematic of Ion Chromatograph

NOTICE: SEMI makes no warranties or

representations as to the suitability of the standards set

forth herein for any particular application. The

determination of the suitability of the standard is solely

the responsibility of the user. Users are cautioned to

refer to manufacturer’s instructions, product labels,

product data sheets, and other relevant literature

respecting any materials mentioned herein. These

standards are subject to change without notice.

The user’s attention is called to the possibility that

compliance with this standard may require use of

copyrighted material or of an invention covered by

patent rights. By publication of this standard, SEMI

takes no position respecting the validity of any patent

rights or copyrights asserted in connection with any

item mentioned in this standard. Users of this standard

are expressly advised that determination of any such

patent rights or copyrights, and the risk of infringement

of such rights, are entirely their own responsibility.

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consent of SEMI.