Top 5 BGA Rework Challenges

  • Published on
    11-Apr-2017

  • View
    112

  • Download
    1

Embed Size (px)

Transcript

  • Shielding of Neighboring Devices

    There are some lithium batteries found in hand held devices that can withstand reflow temps*

  • Shielding of Neighboring Devices

    Finally, The IMC formed before soldering is proved to decrease the bond strength between the Sn and the Cu substrate as the IMC thickness increases. Samsun Paper 2008The shear strength decreased with increasing agingtemperature and time. The IMC layer thickness was found to increase linearlywith the square root of aging time and the growth wasobserved to be faster for higher aging temperatures. Department of Advanced Materials Engineering, Sungkyunkwan University,*

  • Experimental Method

    Shielding of Neighboring Devices

    *

  • Experimental Method

    Shielding of Neighboring Devices

    *

  • Experimental Method

    Shielding of Neighboring Devices

    *

  • Experimental Method

    Shielding of Neighboring Devices

    *

  • Experimental Method

    Shielding of Neighboring Devices

    *

  • Clay Gel

    Shielding of Neighboring Devices

    *

  • Results

    Shielding of Neighboring Devices

    Distance from test ICSpeaker 30.95mmBattery 9.73mmConnector 6.14mmRework LocationControl (no shields)123 C177 C227 C232 CCopper Tape106 C129 C128 C232 CStainless Steel61 C143 C158 C239 CClay/Water Gel66 C86 C89 C231 CKapton Tape99 C145 C153 C241 CCeramic Fiber63 C111 C113 C231 C

    *

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Issue # 3Underfill

    Can use this profiling technique OR have an engineering sample where theromocoules can be embedded OR an experience profile based on guestimatingTypicslly we are looking at:Time above liquidus (183 C for lead free sodler)Peak temp-compoentn can withstandRamp rateDelta T across the componentNo adjacent reflow of BGAsTopside less than 240C*

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Standard Hot Air Method-Post Device RemovalUnderfilled BGAs

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Standard Hot Air Method-Post Device RemovalUnderfilled BGAs

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Standard Hot Air Method-Post Device RemovalUnderfilled BGAs

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Standard Hot Air Method-Post Device RemovalUnderfilled BGAs

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Chemical Softening and Standard Hot Air Method-Post Device RemovalUnderfilled BGAs

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Chemical Softening and Standard Hot Air Method-Post Device RemovalUnderfilled BGAs

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Chemical Softening and Standard Hot Air Method-Post Device RemovalUnderfilled BGAs

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Underfill

    Automated Site Redressing MethodHot gas and vaccuum tool in one. This os on XY robot and for the more sophisticated systems includes the movement up/down a fixed distance from the baord via a sensorASR is s lower metho but elimnates the mechanical stresses and elimnates pulled padsAbout 3mm per second speedMost cases flux not used so n clean up*

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Issue # 4Mask Damage

    Can use this profiling technique OR have an engineering sample where theromocoules can be embedded OR an experience profile based on guestimatingTypicslly we are looking at:Time above liquidus (183 C for lead free sodler)Peak temp-compoentn can withstandRamp rateDelta T across the componentNo adjacent reflow of BGAsTopside less than 240C*

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Extensive Mask Damage

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Methods for Mask RepairPensUV-Cured Mask (IPC 7721 2.4.1)Thermally-Cured Mask (IPC 7721 2.4.1)Stay in Place Stencil (IPC 7721 5.7.2)Stenciling Technique (IPC 7721 2.4.2)

    `*

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Pens for Mask Replacement

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Damaged Solder Mask

    *

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Placement of Stencil

    *

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Squeegeeing Mask Through Stencil Apertures

    *

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Damaged Solder Mask Post Removal

    *

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Reduced ball size as solder flows down the via.Solder shortStay-in Place Stencil-Eliminates Shorts

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Stay-in Place Stencil-No Flow of Solder Down Dogbone

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    With Stay-in Place Stencil

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Without Stay-in-Place Stencil

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Issue # 5Lifted Pads

    Can use this profiling technique OR have an engineering sample where theromocoules can be embedded OR an experience profile based on guestimatingTypicslly we are looking at:Time above liquidus (183 C for lead free sodler)Peak temp-compoentn can withstandRamp rateDelta T across the componentNo adjacent reflow of BGAsTopside less than 240C*

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Damaged/Lifted Pads Post Removal

    *

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Damaged/Lifted Pads Post Removal

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Damaged/Lifted Pads Post Removal

    *

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    Pad Repair IPC 7721 4.7.1 Epoxy or 4.7.2 Film

    *

    Your BEST choice in Solder Rework/Repair/Test, Solder Training & Soldering Tools

    BGA Rework-Big ChallengesTop 5 BGA ChallengesWarped BGAs Neighboring Device DamageUnderfill ReworkExtensive Mask DamagePad Damage

    www.solder.net

    `*

    `*Can use this profiling technique OR have an engineering sample where theromocoules can be embedded OR an experience profile based on guestimatingTypicslly we are looking at:Time above liquidus (183 C for lead free sodler)Peak temp-compoentn can withstandRamp rateDelta T across the componentNo adjacent reflow of BGAsTopside less than 240C*Wnt the preheater larege enough so no large delta T on bottomside of the assemblyVerified with thermocouples*Do not want the board supports to act as a thermal sinkProblems in high thermal mass boards with uneven ground plane/copper place distributions OR very thin boardsCoplanarity is he highest point above the seating plane-JEDEC defines this-can lead to opens and shorts on the BGA*Caution has to be used because excessive heat or pressure will lift the landsSwabbing the deck will scrath the mask*Can use this profiling technique OR have an engineering sample where theromocoules can be embedded OR an experience profile based on guestimatingTypicslly we are looking at:Time above liquidus (183 C for lead free sodler)Peak temp-compoentn can withstandRamp rateDelta T across the componentNo adjacent reflow of BGAsTopside less than 240C*There are some lithium batteries found in hand held devices that can withstand reflow temps*Finally, The IMC formed before soldering is proved to decrease the bond strength between the Sn and the Cu substrate as the IMC thickness increases. Samsun Paper 2008The shear strength decreased with increasing agingtemperature and time. The IMC layer thickness was found to increase linearlywith the square root of aging time and the growth wasobserved to be faster for higher aging temperatures. Department of Advanced Materials Engineering, Sungkyunkwan University,*

    *

    *

    *

    *

    *

    *

    *Can use this profiling technique OR have an engineering sample where theromocoules can be embedded OR an experience profile based on guestimatingTypicslly we are looking at:Time above liquidus (183 C for lead free sodler)Peak temp-compoentn can withstandRamp rateDelta T across the componentNo adjacent reflow of BGAsTopside less than 240C*Automated Site Redressing MethodHot gas and vaccuum tool in one. This os on XY robot and for the more sophisticated systems includes the movement up/down a fixed distance from the baord via a sensorASR is s lower metho but elimnates the mechanical stresses and elimnates pulled padsAbout 3mm per second speedMost cases flux not used so n clean up*Can use this profiling technique OR have an engineering sample where theromocoules can be embedded OR an experience profile based on guestimatingTypicslly we are looking at:Time above liquidus (183 C for lead free sodler)Peak temp-compoentn can withstandRamp rateDelta T across the componentNo adjacent reflow of BGAsTopside less than 240C*`*

    *

    *

    *

    *Can use this profiling technique OR have an engineering sample where theromocoules can be embedded OR an experience profile based on guestimatingTypicslly we are looking at:Time above liquidus (183 C for lead free sodler)Peak temp-compoentn can withstandRamp rateDelta T across the componentNo adjacent reflow of BGAsTopside less than 240C*

    *

    *

    *`*

Recommended

View more >