Factbook Cobar OT2 Virtual

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1 Factbook OT2 Table of Contents 01 Table of contents 02 Handling guidelines OT2 solder paste 03 Printing continuous printing process window 04 Printing interval printing process window 05 Recommended reflow profile 06 Viscosity of solder paste 07 Tackiness: force and time (JIS Z 3284 Annex 9) 08 Cold slump (IPC-TM-650, Method ) 09 Hot slump (IPC-TM-650, Method ) 10 Solder ball test (IPC-TM-650, Method ) 11 Wetting test (IPC-TM-650, Method ) 12 Surface Insulation Resistance (IPC-TM-650 Method ) 13 Electro-migration test (IPC-TM-650, Method ) 14 Copper mirror test (IPC-TM-650 Method Rev. D) 15 Copper corrosion 16 Product Data Sheet 17 SGS report Analytical report 18 MSDS document 19 Contact Table of Contents Handling Latest update

2 Factbook OT2 Handling guidelines OT2 solder paste Solder paste is sensitive to temperature and humidity. For this reason the shelf life of the paste is limited thus logistics and handling become important. Handling solder paste properly will preserve the original characteristics of the solder paste longer and minimize waste of solder paste. Table of Contents Handling Transportation: Transportation time should be limited as much as possible to minimize the exposure to the environment. Temperatures below 5 C and above C should be avoided. Insulation materials, ice packs, dry ice or gel packs may be used in hot climates. Receiving: Remove the shipping container from the jar/cartridge before storing the paste. The shipping container is meant for transportation only to a maximum of 4 days. Immediately upon receipt, unpack shipping container. Refrigerated storage will prolong the shelf-life. Store unopened in a refrigerator, when products will not be used or inspected within the next few days. Recommended storage temperature is 4-10 C. Temperatures below 4 C, however, should be avoided. In any case, storage temperatures should not exceed C. Air-conditioned temperatures are usually adequate for storage. In the case of solder creams packed in cartridges it is recommended to store them in horizontal position. To eliminate flux segregation it is advised to rotated the cartridges once a month. Handling: First in first out principle should be applied in the refrigerator storage of the jars. Batch age can be identified by the expiry date on the label on the jar or cartridge. Allow minimum 8 hours for jars and their content to reach the ambient temperature. Allow the jar/cartridge to reach ambient temperature naturally. Do not place on a hot plate, furnace, reflow oven or any other artificial means to warm. DO NOT open frozen/cold containers as moisture may condense on the product and affect performance. Stir the material for 1 minute with a steel spatula (or equivalent). Generally it is not recommended to re-use paste that already has been on a stencil for more than two days. In other cases the un-dried portion of the cream may be returned into the jar after use. Never put used paste back into a jar containing fresh paste. This will alter rheology of unused paste. When handled and stored properly, the minimum shelf-life is: 1,5 months at 20 C and 6 months at 8-10 C. For safety aspects during storage and handling we refer to our Material Safety Data Sheet.

3 Factbook OT2 Printing - continuous In order to quantify the print performance of the solder paste a dynamic print test has been performed. Without pause 20 boards were printed. The stencil was cleaned after 3 boards. Boards 1, 10, 11 and 20 were inspected inmediately after printing. Printer settings can be found in the table. Printing Process 1 Printing Process 2 Reflow Voiding BGA pattern Square/round patterns

4 Factbook OT2 Printing interval test In order to quantify the print performance of the solder paste a dynamic print test has been performed. Without pause 20 boards were printed. The stencil was cleaned after 3 boards. Boards 1, 10, 11 and 20 were inspected inmediately after printing. Printer settings can be found in the table. Printing Process 1 Printing Process 2 Reflow Voiding BGA pattern Square/round patterns

5 Factbook OT2 Reflow profile The melting point of SAC305 is 217 ºC. In order to achieve a good coalescence of the solder the time above the melting point should be at least 30 seconds. The minimum required peak temperature for this alloy is 230 ºC. Recommended profile: Following process time suggestion should be considered as a minimum energy requirement. It ensures a smooth and complete evaporation of the solvents and optimum activation of the flux. This will provide the best wetting results and minimize the residues. Printing Process 1 Printing Process 2 Reflow Voiding Figure 1: Process window for the SAC305 solder paste. FAT = Flux Activation Time, Tp = Peak Temperature, TAL = Time Above Liquidus. * SCAN-Ge071 identical to SAC305 ** SN100C identical, except Tp min 240 C

6 Factbook OT2 Voiding: During the melting of the solder paste in the reflow oven the powder and copper oxides (from the surface to be soldered) melt and disappear as a flux residue in the peak/cooling zone of the oven. The part that is trapped in the solder will remain there as a void. OT2 solder paste flux is designed to be low in voiding. Different components are soldered with a typical lead free OT2 SAC3 solder paste and compared with solder paste. X-ray machines are used to visualize the remaining voids in the soldered joints. Printing Process 1 Printing Process 2 Reflow Voiding OT2-SAC3 Competitive product

7 Factbook OT2 Viscosity of solder paste Viscosity is the degree to which a solder paste resists flow under an applied force. It describes the internal friction of solder paste. For an accurate measuring method a rheometer with parallel plates is used. The temperature 25 C is kept constant during the measurement by a Peltier-element, providing an accuracy of 0.1 ºC. A plate of 30 mm is used and the gap between the bottom an upper plate is 1 mm. Since the history of the paste affects the viscosity the time between measurement and the production of the paste is longer then 24 hrs. After stirring the paste is hold for 1 hour to relax and have a repeatable measurement. Viscosity Tackiness Cold slump Hot slump Solder balling Wetting test Figure 1: The curve from the rheometer viscosity is defined at a shear strain rate of 6 (1/s)

8 Tackiness vs time (according to JIS Z 3284 Annex 9) Viscosity Tack force and time are important properties of a solder paste. Tackiness force to keep the components on its place during SMD assembly. The tack time is important to eliminate soldering defects like component movement and tomb stoning. Tackiness Cold slump Hot slump Solder balling Wetting test For the SAC3-OT2 is the tackforce after 24 hours is still acceptable. Figure 1: Schematic overview of the tack test. Probe dips into the solder deposit and is lifted out during which the force is monitored.

9 Solder paste Cold slump test (IPC-TM-650, Method ) Viscosity This procedure determines vertical and horizontal slump for the SAC3-OT2 solder paste. In this first part of the slump test only the cold resistance slump is evaluated. Cold slump resistance: The specimens are stored for 15 minutes at 25 +/ 5 C and 50% relative humidity +/ 10% and specimen #1 (stencil IPC-A-20 thickness 0.15 mm) examined for slump. Criteria: The printed pattern shall be uniform in thickness with no solder particles separated from the pads. Tackiness Cold slump Hot slump Solder balling Wetting test Figure 1: Slump after 15 minutes at 25 C Pass: No bridging on pads spacedequal or greater then 0.20 mm.

10 Solder paste Hot slump test (IPC-TM-650, Method ) Viscosity This procedure determines vertical and horizontal slump for SAC3-OT2 solder paste. The IPC standard is not modified for lead-free solder pastes yet. For the experiment we use ceramic and copper specimen. According to IPC standard the specimen was printed and placed in an oven set at 150 C +/ 10 C for 15 minutes, cooled to ambient and examined for slump. Criteria: The printed pattern shall be uniform in thickness with no solder particles separated from the pads. Tackiness Cold slump Hot slump Solder balling Wetting test Pass: No bridging on pads spaced equal or greater then 0.20 mm.

11 Solder ball test (IPC-TM-650, Method ) Viscosity The solder ball test is designed to determine the reflow properties of a solder paste. It shows the ability of solder particles in the paste to reflow into a sphere on a non-wettable surface. After printing with a 0.2 mm stencil (diameter apertures 6.5 mm) the coupons were heated on a liquidus solder bath of 242 C ± 3 C. Of the two samples one was soldered and the other was stored for 24 hours at 25 C and 50% RH before soldering. The first sample passed the test with a class 1 score. The second sample that was stored for 24 hours also passed the IPC criteria with a class 1 score. Tackiness Cold slump Hot slump Solder balling Wetting test

12 Solder paste wetting test (IPC-TM-650, Method ) Viscosity Objective of this experiment is to determine the ability of a solder paste SAC3-OT2 to wet an oxidized copper surface and to qualitively examine the amount of spatter of solder paste during reflow. The copper specimen is rinsed with isopropyl alcohol and dried. Solder paste is printed on the specimen and reflowed in a forced convection reflow oven using a 5 minutes heating profile with a peak temperature of 245 C and a TAL (Time Above Liquidus) of 60 seconds. After the wetting the diameters are defined using a microscope. Tackiness Cold slump Hot slump Solder balling Wetting test Copper the solder wets uniformly the copper and there is no evidence of dewetting or non-wetting of the copper and there are no solder spatter around the printed dots.

13 Surface Insulation Resistance measurements (IPC-TM-650 Method ) SIR This test is to determine the degradation of electrical insulation resistance of a printed circuit board after soldering with the SAC3-OT2 solder paste. The SIR test is performed at elevated temperatures and humidity (85 ± 2 C and 85 ± 2 % RH) for 168 hrs. The coupons were placed in an environmental chamber in a vertical position such that airflow was parallel to the board surfaces, with at least 12.7 mm spacing between coupons. The chamber was set to 85 ± 2 C and 20% RH and allowed to stabilize for 3 hours. The humidity was then ramped to 85 ± 2 % over a 30 minute period. The coupons were allowed to equilibrate for two hours before applying the bias voltage to begin the test. A bias of -50 volts DC was applied to all test coupons. At 24, 96, and 168 hours, insulation resistance measurements were made with +100 volts DC applied the comb patterns A, B, C, and D of each IPC B-24 coupon. The measurement voltage was opposite in polarity to the bias voltage. Electro migration Copper mirror Copper corrosion SAC3-OT2 passes the SIR test.

14 Electrochemical migration resistance (IPC J-STD-004A, paragraph and IPC-TM-650, Method ) SIR This test method provides a means to assess the propensity for surface electrochemical migration. The chamber was then closed and activated. The temperature and humidity settings for the test were 65 ± 2 C and 85 ± 3.5% R.H. The samples were allowed to stabilize at the conditions for 96 hours. After this stabilization period, the initial insulation resistance measurements were taken under the test conditions. The measurements were made using 100 VDC between terminals. When the measurements were complete, a 10 VDC bias was placed on the samples with limiting resistors. The bias voltage was the same polarity as the measurement voltage. After 404 hours of applied bias (500 hours of total exposure), the bias was removed and measurements were obtained as described above. After completion of the exposure, the samples were visually inspected with backlighting at 10x for evidence of electrochemical migration, discoloration, and corrosion. Electro migration Copper mirror Copper corrosion SAC3-OT2 passes the test.

15 Corrosion by Copper Mirror (IPC-TM-650 Method Rev. D) SIR This test method is designed to determine the removal effect the flux has (if any) on the bright copper mirror film, which has been vacuum, deposited on clear glass. The flux shall be classified as type L only if there is no removal of the copper film. If there is any removal of the copper film, as evidenced by the background showing through the glass, then the flux shall be classified as type M or H. One drop of the test flux or solder paste is placed on the copper mirror test panel carefully as to not allow the dropper to touch the test panel. One drop of the control standard flux is immediately placed adjacent to the test flux being careful to not allow the drops to touch. The test panels are then placed in a horizontal position in a dust free cabinet at 23 ± 2ºC and 50 ± 5% relative humidity for 24 ± ½ hours. At the end of the 24-hour period, the samples are removed from the test cabinet. The test flux and control flux are removed by immersion in clean 2-propanol. The test panels are then examined for copper removal or discoloration. Electro migration Copper mirror Copper corrosion The SAC3-OT2is qualified as type L: no removal of the copper film. Figure 1: Photo of the test sample. The SAC3-OT2 flux sample placement is on right.

16 Copper Corrosion (IPC-TM-650 Method ) SIR This test method is designed to determine the corrosive properties of flux residues under extreme environmental conditions. Method is described in the IPC-TM-650 Method Storage conditions: 240 hrs (10 days) humid storage at 40 C ± 1 ºC/ 93 ± 2% relative humidity.. Electro migration Copper mirror Copper corrosion The SAC3-OT2 is qualified as type L: no copper corrosion detected. Figure 1: Sample before and after storage

17 Introduction Process Properties Test data Contact: Europe BV Balver Zinn Solder Products PO Box DG Breda, Holland Aluminiumstraat AL Breda, Holland 143 Telephone: Telefax: info@cobar.com Internet: Josef Jost GmbH & Co.KG Blintroper Weg Balve Germany Telephone: Telefax: cia@balverzinn.com Internet: com 53 Wentworth Ave NH Londonderry United States of America Telephone: Telefax: info.usa@cobar.com Internet: Documents Balver Zinn/ 111 North Bridge Road # Peninsula Plaza Singapore Telephone: Internet: Disclaimer: The information given in this publication has been worked up to the best of the knowledge of as well as taking into consideration the applicable laws and regulations. We cannot anticipate all conditions under which this information and our products or the products of other manufacturers in combination with our products may be used. We accept no responsibility for results obtained by the application of this information or the safety and suitability of our products alone or in combination with other products. Users are advised to make their own tests to determine the safety and suitability of each such product or product combination for their own purposes. Unless otherwise agreed in writing, we sell the products without warranty, and buyers and users assume all responsibility and liability for loss or damage arising from the handling and use of our products, whether used alone or in combination with other products. Product Data Sheet SGS Report MSDS document Contact