AN0333 APPLICATION NOTE 0333 REFLOW SOLDER PROFILE RECOMMENDATION Introduction This application note provides guidelines for Diodes® semiconductor packages relating to: • the board mounting • recommended reflow solder profiles This guideline based on IPC/JEDEC J-STD-020D.1 March 2008. Diodes® semiconductor devices are plated with matte Tin (Pure Sn). They can be used in standard lead-free Tin-Silver-Copper (Sn-Ag-Cu) and also in Tin-Lead (SnPb) applications. From environmental point of view Diodes recommend to use standard leadfree Tin-Silver-Copper (Sn-Ag-Cu). Reflow Profile Recommendations for Tin Lead and Lead-Free Soldering Herein after listed information are recommendations and for reference only. Users are advised to optimize their own board level materials, parameters and equipment to get proper reflow outcome. The maximum number of reflow cycles, which can be done on Diodes® products is limited by 3. Table 1: SnPb Eutectic Process – Classification Temperature (TC) 3 Package Thickness Volume mm < 350 < 2.5mm 235 +0/-5°C 225 +0/-5°C ≥ 2.5mm Table 2: Pb-Free Process – Classification Temperature (TC) 3 Package Thickness Volume mm < 350 < 1.6mm 1.6mm – 2.5mm ≥ 2.5mm Notes: 3 Volume mm ≥ 350 225 +0/-5°C 225 +0/-5°C 260 + 0°C 260 + 0°C 260 + 0°C 3 Volume mm 350-2000 260 + 0°C 250 + 0°C 245 + 0°C 3 Volume mm ≥ 350 260 + 0°C 245 + 0°C 245 + 0°C 1. At the discretion of the device manufacturer, but not the board assembler/user, the maximum peak package body temperature (Tp) can exceed the values specified in Table 1 or Table 2. The use of a higher Tp does not change the classification temperature (Tc). 2. Package volume excludes external terminals (e.g., balls, bumps, lands, leads) and/or non-integral heat sinks. 3. The maximum component temperature reached during reflow depends on package thickness and volume. The use of convection reflow processes reduces the thermal gradients between packages. However, thermal gradients due to differences in thermal mass of SMD packages may still exist. 4. Moisture sensitivity levels of components intended for use in a Pb-free assembly process shall be evaluated using the Pb-free classification temperatures and profiles defined in Table 2 and Table 3, whether or not Pb-free. 5. SMD packages classified to a given moisture sensitivity level by using Procedures or Criteria defined within any previous version of J-STD-020,JESD22-A112 (rescinded), IPC-SM-786 (rescinded) do not need to be reclassified to the current revision unless a change in classification level or a higher peak classification temperature is desired. 6. Temperature tolerances: The device manufacturer/supplier shall assure process compatibility up to and including the stated classification temperature at the rated MSL level (this means peak reflow temperature +0°C). AN0333 Document number: Rev. 1 - 2 1 of 4 www.diodes.com May 2014 © Diodes Incorporated AN0333 Reflow Profile Recommendations for Tin Lead and Lead-Free Soldering (cont.) Table 3: Classification Reflow Profile Profile Feature Temperature Min (TSMIN) Temperature Max (TSMAX) Time (ts) from (TSMIN to TSMAX) Average ramp-up rate (TSMAX to TP) Liquidus temperature (TL) Time (tL) maintained above TL Peak package body temperature (TP) Sn-Pb Eutectic Assembly 100°C 150°C 60-120 seconds 3 °C/second max. 183°C 60-150 seconds TP must not exceed the Classification Temp in Table 1 Pb-Free Assembly 150°C 200°C 60-120 seconds 3 °C/second max. 217°C 60-150 seconds TP must not exceed the Classification Temp in Table 2 Time (tp)* within 5 °C of the specified 20* seconds 30* seconds classification temperature (TC), see Figure 1. Average ramp-down rate (TP to TSMAX) 6°C/second max. 6°C/second max. Time 25°C to peak temperature TP 6 minutes max. 8 minutes max. * Tolerance for peak profile temperature (TP) is defined as a supplier minimum and a user maximum. Notes: 7. Tolerance for peak profile temperature (Tp) is defined as a supplier minimum and a user maximum. 8. Tolerance for time at peak profile temperature (Tp) is defined as a supplier minimum and a user maximum. 9. All temperatures refer to the center of the package, measured on the package body surface that is facing up during assembly reflow (e.g., live-bug). If parts are reflowed in other than the normal live-bug assembly reflow orientation (i.e. dead-bug), Tp shall be within ± 2°C of the live-bug Tp and still meet the Tc requirements. Otherwise, the profile shall be adjusted to achieve the latter. To accurately measure actual peak package body temperatures, refer to JEP140 for recommended thermocouple use. 10. Reflow profiles in this document are for classification/preconditioning and are not meant to specify board assembly profiles. Actual board assembly profiles should be developed based on specific process needs and board designs and should not exceed the parameters in Table 3. For example, if TC is 260°C and time tp is 30 seconds, this means the following for the supplier and the user. For a supplier: The peak temperature must be at least 260°C. The time above 255°C must be at least 30 seconds. For a user: The peak temperature must not exceed 260°C. The time above 255°C must not exceed 30 seconds. 11. All components in the test load shall meet the classification profile requirements. 12. SMD packages classified to a given moisture sensitivity level by using Procedures or Criteria defined within any previous version of J-STD-020, JESD22-A112 (rescinded), IPC-SM-786 (rescinded) do not need to be reclassified to the current revision unless a change in classification level or a higher peak classification temperature is desired. AN0333 Document number: Rev. 1 - 2 2 of 4 www.diodes.com May 2014 © Diodes Incorporated AN0333 Reflow Profile Recommendations for Tin Lead and Lead-Free Soldering (cont.) Figure 1: Reflow Profile Recommendation Revision History Revision No Rev. 1 AN0333 Document number: Rev. 1 - 2 Date February 17th, 2014 3 of 4 www.diodes.com Description Initial Reflow Solder Profile Recommendation May 2014 © Diodes Incorporated AN0333 Contact Information For further information or assistance please contact: Diodes' website at www.diodes.com or Corporate Headquarters and Americas Sales Office 4949 Hedgcoxe Road, Suite 200, Plano, TX 75024 USA T: 972-987-3900 F: 972-731-3510 E: [email protected] IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2014, Diodes Incorporated www.diodes.com AN0333 Document number: Rev. 1 - 2 4 of 4 www.diodes.com May 2014 © Diodes Incorporated