With Title Change To: Test Method for Measurement of Ionic Contamination on Semiconductor

Background Statement for SEMI Draft Document 5838
Revision toSEMI G52-90 (Reapproved 1104), Standard Test Method for Measurement of Ionic Contamination on SemiconductorLeadframes (Proposed)

with title change to: Test Method for Measurement of Ionic Contamination on Semiconductor Leadframes

Notice: This background statement is not part of the balloted item. It is provided solely to assist the recipient in reaching an informed decision based on the rationale of the activity that preceded the creation of this Document.

Notice: Recipients of this Document are invited to submit, with their comments, notification of any relevant patented technology or copyrighted items of which they are aware and to provide supporting documentation. In this context, “patented technology” is defined as technology for which a patent has issued or has been applied for. In the latter case, only publicly available information on the contents of the patent application is to be provided.

Notice: Additions are indicated by underline and deletions are indicated by strikethrough.

Background

SEMI G52-90 (Reapproved 1104) is due for 5-year review.

The Japan TC Chapter of Assembly & Packaging Global Technical Committee approved the letter ballot distribution for the revision of SEMI G52-90 (Reapproved 1104)at the meetingheld on January 20, 2015. This technical ballot is intended for the revision of SEMI G52-90 (Reapproved 1104). The following chapters are the whole document of revision of SEMI G52-90 (Reapproved 1104).

Review and Adjudication Information

Task Force Review / Committee Adjudication
Group: / Packaging 5 Year Review Task Force / Japan TC Chapter of Assembly & Packaging Global Technical Committee
Date: / TBD / May 11, 2015
Time & Timezone: / TBD / 15:00-17:00 [JST]
Location: / SEMI Japan, Ichigaya Office / SEMI Japan, Ichigaya Office
City, State/Country: / Tokyo, Japan / Tokyo, Japan
Leader(s)/Author(s): / Masahiro Tsuriya(iNEMI)
/ Kazunori Kato (AiT)
Masahiro Tsuriya (iNEMI)
Yutaka Koma (Consultant)
Standards Staff: / Chie Yanagisawa (SEMI Japan)
81.3.3222.5863
/ Chie Yanagisawa (SEMI Japan)
81.3.3222.5863

Task Force Review meeting’s details are to be decided. If you need the details, please contact the task force leader or Standards staff for confirmation.

Telephone and web information will be distributed to interested parties as the meeting date approaches. If you will not be able to attend these meetings in person but would like to participate by telephone/web, please contact Standards staff.

Chie Yanagisawa

SEMI Standards, SEMI Japan

Tel: 81.3.3222.5863

Email:

Semiconductor Equipment and Materials International

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San Jose, CA95134-2127

Phone:408.943.6900, Fax: 408.943.7943

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Background Statement for SEMI Draft Document 5838
Revision to SEMI G52-90 (Reapproved 1104),
Standard Test Method for Measurement of Ionic Contamination on Semiconductor Leadframes (Proposed)

with title change to: StandardTest Method for Measurement of Ionic Contamination on Semiconductor Leadframes(Proposed)

1 Scope

1.1 This standard describes the procedure to determine ionic contamination on leadframes using a water extraction method. The method is sensitive to Na+, NH4+, K+, Cl−, NO3-, Br−, SO42−, PO43−.

NOTICE:SEMI Standards and Safety Guidelines do not purport to address all safety issues associated with their use. It is the responsibility of the users of the Documents to establish appropriate safety and health practices, and determine the applicability of regulatory or other limitations prior to use.

2 Referenced Standards

2.1 ASTM Specifications[1]

D 1193 — Specification for Reagent Water

D 4327 — Anions in Water by Ion Chromatography

NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.

3 Summary of Method

3.1 Ionic contamination is extracted in water at > 95°C for 30 ± 2 minutes. The contamination is quantitatively analyzed by ion type using Ion Chromatography and the result is presented as nanograms/unit area.

4 Significance

4.1 Contamination on leadframes can contribute to semiconductor device reliability problems. This method may be used by lead frame manufacturers at outgoing inspection and by users at incoming inspection. Correlation of device reliability with contamination levels may lead to improved leadframe cleaning processes.

5 Terminology

5.1 Definitions

5.1.1 eluent — the solvent used to carry the extracted ions through the ion exchange chromatograph.

5.1.2 regenerant — a chemical solution containing the ions originally present in the chromatograph column prior to a test run and used to prepare the column for a new test.

5.1.3 retention time — the time required for a particular ion type to pass from the injection port to the detector. Retention time is characteristically different for each ion type.

5.1.4 standard solution — a solution containing a known concentration of the ion to be measured and used to calibrate the chromatograph.

6 Equipment

6.1 Ion Chromatograph for Anion and Cation Analysis — This equipment is to consist of a concentration pump, guard column, separator column, and a detector module consisting of a suppressor device to reduce the background eluent conductivity to a low level and a conductivity cell. The minimum sensitivity of the chromatograph for each ion type is defined in Table 1.

Table 1Sensitivity of Ion Chromatograph

Ion / Sensitivity (ng/ml)
Cation / Na+ / 0.2
NH4+ / 0.5
K+ / 1.0
Anion / Cl− / 0.3
PO43− / 2.0
Br- / 1.0
NO3- / 1.0
SO42- / 1.0

6.2 Chart Recorder

6.3 Ion Extraction Vessels — Polypropylene or teflon containers with sealing caps, or polypropylene/ polyethylene double layered bags.

NOTE 1:The contamination level of these vessels must be less than one-fifth (1/5) of the expected contamination level on the leadframes when measured in a control test.

6.4 Hot Bar Bag Sealer

6.5 Water Bath — 300 mmL × 300 mmW × 200 mmH, filled with DI water, and capable of holding 95°C.

6.6 Volumetric Dispenser (e.g., Pipettes) — 10 ml and 100 ml capacity.

6.7 Quartz Flasks and Pipettes for Cation Standard Solutions — 100, 250, 500, and 1000 ml capacity (flasks); 1, 10, and 25 ml capacity (pipettes).

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, NH4Cl, KC1.

7.3.1 Compounds for Anion Standard Solutions — NaCl, Na2HPO4, 12H2O, NaBr, NaNO3, K2SO4.

NOTE 2: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 cm2 for testing pads and 200–500 cm for the test of overall leadframes.

NOTE 3: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+, NH4+, K+; C1−, No3-, Br-, SO42−, PO43−) 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.

Table 2Concentration 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
NH4+ / 10 / 5 / 10 / 20
K+ / 10 / 5 / 10 / 20
Anion / Cl− / 4 / 10 / 20 / 40
PO43− / 10 / 25 / 50 / 100
Br− / 4 / 10 / 20 / 40
NO3− / 4 / 10 / 20 / 40
SO42− / 4 / 10 / 20 / 40

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 4: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 5: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 6: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 7: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.

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 8: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 9: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 10: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 11: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 12: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:

NOTE 13:Allowable concentration levels are to be agreed between the user and supplier.

Table 1 Sensitivity of Ion Chromatograph

Ion / Sensitivity (ng/ml)
Cation / Na+ / 0.2
NH4+ / 0.5
K+ / 1.0
Anion / Cl− / 0.3
PO43− / 2.0
Br- / 1.0
NO3- / 1.0
SO42- / 1.0

Table 2 Concentration of Standard Solution for Calibration

Figure 1
Schematic of Ion Chromatograph

NOTICE:Semiconductor Equipment and Materials International (SEMI) makes no warranties or representations as to the suitability of the Standards and Safety Guidelines set forth herein for any particular application. The determination of the suitability of the Standard or Safety Guideline 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 or equipment mentioned herein. Standards and Safety Guidelines are subject to change without notice.

By publication of this Standard or Safety Guideline, SEMI takes no position respecting the validity of any patent rights or copyrights asserted in connection with any items mentioned in this Standard or Safety Guideline. Users of this Standard or Safety Guideline 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.

This is a Draft Document of the SEMI International Standards program. No material on this page is to be construed as an official or adopted Standard or Safety Guideline. Permission is granted to reproduce and/or distribute this document, in whole or in part, only within the scope of SEMI International Standards committee (document development) activity. All other reproduction and/or distribution without the prior written consent of SEMI is prohibited.

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