void reduction

"void reduction" search results in the Electronics Forums

1503 results found for "void reduction" in the Electronics Forums

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What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles?

Mar 17, 2017 | I think the main driver is MTBF data driven by the Car OEMS, mainly german makers pushing this onto suppliers in supply chain. Vacuum soldering and void reduction is a hot topic for the leading electronics suppliers in Germany at the moment. Is not related to and IPC type standards, it is more What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles? market share. Vacuum Soldering can also be done in Vapor phase, again this was championed by Rehm before most other vendors, due again being close to where lower and lower void quality requirement demands are coming from... Paste flux does contribute so much to reducing voids and more work in this area

What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles?

Mar 15, 2017 | What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles? Customer precedes standard, but customer must be educated and informed on what is achievable with their design and what is accepted as industry standard practice. My guess is that the negative effect of those voids is negligible. {Voids at the solder interface on the thermal pads} Here is a fact that I do know. People get nervous when they see voids in an x-ray image.

What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles?

Mar 15, 2017 | Hi PZ, What, sort of like this one? http://creativeelectron.com/papers/EconomicsofLEDVoiding.pdf It even has the handy calculation for the reduction in thermal performance with voiding. What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles?

What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles?

Mar 15, 2017 | What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles? From what I know, you should follow IPC standard for the class assembly that you are building. From your post somebody mentioned something somewhere - doesn't make it official information. I would not be worried about having voids, but what is their location and size. You absolutely don't want voids on your signal pads of the QFN. Big voids lead to failures. I have read several articles, claiming that small voids actually improve the strength of the solder joint. Solder paste and proper stencil design help reduce voiding.

What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles?

Mar 15, 2017 | What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles? It's well documented in higher power semiconductors where thermal interface materials are used, such as SIL pads, thermal grease etc. There are a couple of papers on the effects of voiding on MOSFET performance, but I haven't got around to reading them yet, but you should be able to transpose the physics directly to LEDs as well. Regarding the reduction in Thermal performance, it's real, not theoretical - the thermal conductivity of Copper is about 16,000 times better than air. However I have no idea what the thermal conductivity of a no clean flux is as that is probably going to be what

0201 (0603) stencil spec

May 7, 2014 | It really depends on pad design and other component on the PCB. Most of the time I run 0201s I have microBGAs on the board and usually print 3mil. Reduction will depend on the paste. For leaded paste you will have reduction (about 10% or so).For LeadFree, you can have some reduction or you can

QFN PCB Pad no Drain Hole

May 31, 2013 | as an inspection point, in that wetting to the PWB can be observed through the via from the backside. Use a grid pattern for your apertures for improved outgassing during flux activation. The other picture (small Thermal Vias) I would do a straight up 35-40% reduction in printed area, and use a grid pattern to help with the outgassing during the flux activation stage. These really shouldn't be that tough. And as always, solderability is king. Re-tinning of these parts prior to use has also been utilized in cases where we can't get the voiding out through normal processes. Just my $.02, but based on a

QFN PCB Pad no Drain Hole

May 22, 2013 | results with these mods, but a solder paste that is designed for low voiding and a solid square deposit with a 10-20% reduction in the center has worked the best for us. The voiding will never go away and really you dont want it to, there is a necessity for voiding in the gnds of these devices, but your Customer may want a certain amount of contact area on the gnd. (usually 79% if your Customer cares) The voiding that you are looking for should be many small voids almost like champagne bubbles.What you dont want is large Voids that constitute a high % of the overall void area. As an experiment you might try taking a device and tinning it and then wicking it semi-flat (this isnt that critical) and then flux the device place it and reflow. The results should be pretty good, especially the voiding. I want to warn you about surface finishes not too long ago we had a almost similar issue the voiding

QFN PCB Pad no Drain Hole

May 17, 2013 | I am familiar with TI's documents on QFN mounting. I do not have an X-Ray machine, so I worry about excessive voiding that could happen with using the thermal vias improperly. As a general rule-of-thumb, I print paste with a 25% reduction on the thermal pads to keep the part from floating. TI

Voids with LGAs

Feb 1, 2013 | We have had some success in void reduction with LGA by pre-tinning or "bumping" the devices before placement. The extra solder seems to allow a slightly higher standoff, and allows better outgassing, is my guess. A lot more labor , but the results are notable. You can also experiment with your as the solder pase spec allows can also help with void reduction. Just some ideas that have worked for me in the past. 'hege Voids with LGAs

SMT voiding

Oct 25, 2012 | SMT voiding Here's a paper that may help http://www.ipcoutlook.org/pdf/assembly_challenges_bottom_terminated_ipc.pdf Temperature Impact * Profile didn’t have a significant impact on voiding . * Voids slightly increased with higher temperature. Reflow Atmosphere Impact * Nitrogen didn’t help to reduce voiding amount * Nitrogen could result in less voids but larger voids. Orientation Impact * Orientation didn’t impact the voiding significantly. SMD vs. NSMD Pad * There was no significant

N2 and Voiding??

Oct 17, 2012 | N2 and Voiding?? Has anyone ever experienced void increase while using N2? Thanks for the Help!! anvil

Void control

Oct 11, 2012 | Void control We are experimenting with void control in reflow and have had pretty good luck for the most part in attaining Class lll IPC spec. but we have seen a sudden increase in voiding on a specific product and I was wondering if anyone has seen this extreme voiding before? We were wondering

SMT voiding

Sep 30, 2012 | SMT voiding We believe that Dave's analysis above is mostly accurate. Run a board with no components, and check for voids. We'd also like a little more information, though, to clarify. What type of component is experiencing the voiding? You describe the voiding as "under" the component...are we talking about ground pads, or blind lands under components? The types of lands that are prone to voiding due to the mechanical nature of the part? Is the voiding isolated to any particular area of the board/components? Is the voiding isolated to a single assembly for you, or is it being experienced across

Bottom Termination Parts-Xray Inspection Criteria

Mar 4, 2011 | First, I would inspect for lack of solder bridges from the center slug to the outside leads. I would then look for evidence that the solder paste has reflowed beneath the component, without leaving too much void percentage. Typically we allow up to 25% voiding for these parts, in RF applications I have seen a push towards a much lower void percentage. Controlling the voiding is related to the paste deposition, percentage of coverage of the center pad, and to the pattern by which the paste is deposited on the PCB. For example, a square will leave larger void % than a pattern of dots of the same solder volume. Shoot for about a 30-35% reduction of solder beneath the component. 'hege

Voiding in LGA (LT) soldering

Sep 2, 2010 | Voiding in LGA (LT) soldering I ment LF318. We have a power supply board that has 3 different types of these LGA's and i have had great success with the reductions and stencil thickness mentioned. We had to go with 4 mil stencil due to the consideration of the other large components on the board. I have attached a picture. one

Voiding in LGA (LT) soldering

Sep 1, 2010 | Voiding in LGA (LT) soldering Dear SMT Manufacturer, As moisture is eliminated as the cause then solder paste volume will probably be the main contributing factor. More paste means more chance of solder balls and more flux fumes that need to be evaporated to reduce voiding. Even though it is outside LTs recommendation maybe try 80 micron thick stencil with a small reduction (10% reduction off length and width of pad).

Voiding in LGA (LT) soldering

Aug 31, 2010 | Hi Mark, Thanks for your responce! The stencil thickness and especially the reduction of 45% are not recommend by LT, did you came to this combination experimentally? We never have the illusion to produce voiding free, but now its around the acceptable range. What's the quantity of the LGA's you Voiding in LGA (LT) soldering

Voiding in LGA (LT) soldering

Aug 30, 2010 | We currently use this devise in one of our designs with no issues. We are using a 3mil stencil and a 45% apperature reduction. It is virtually impossible to eliminate voids but they are in an acceptable range. Solder balls are caused on this component if you lay down to much paste. I have built Voiding in LGA (LT) soldering

Voiding in LGA (LT) soldering

Aug 30, 2010 | Voiding in LGA (LT) soldering We having issues installing the Linear Tech LTM8023. We have different soldering results in our PBfree testruns. The voiding and solderball rate is not stable (random positions and sizes). The pcb's (gold finish)are prebaked, the LGA's are stored in Drycabinets etc. We tried already different value's of the following parameters: Stencil thickness, Stencil apperture, stencil reduction, different PCB manufacturers, P&P pressure and reflowprofile. The only item we have not changed is solderpaste, we now use Almit paste. LT and Almit have also investigated the X-ray pictures in combination

BGA Solder Voids

Jun 14, 2010 | BGA Solder Voids What can I do to reduce BGA solder voids?

QFN voiding levels

Jun 10, 2010 | QFN voiding levels 't have a spec for the voiding levels. I do believe they are releasing something soon. Normally, the voiding and solder coverage isn't really a huge problem for components that don't dissipate heat. The vast majority of problems arise from amp circuits that need a solid connection to a ground plane . The via design will vary, depending on the manufacturer of the component, but when you're designing the stencil, try a 30% reduction and try to avoid paste over top of the via's as much as possible. We use a ground aperture design much like BGA apertures, but located where the via's are not. Hope

BGA Voids

May 21, 2010 | BGA Voids Erli, Thanks for your feedback. The BGA hybrids were baked before production. I had a particular date code that we dis-continued using. This date code was consistently voiding near or above 25%. The other date codes still produced voiding on average around 12-16% void sizes which is a process indicator. The manufacturer of the BGAS seems unconcerned if the voiding is under 25% citing the the "Hole-in-pad" issue. All of the other assemblies that I build have no measurable voids. I do get a occasional void of around 5%. Thanks...

BGA Voids

May 19, 2010 | BGA Voids Hello, I'm having problems with voiding on an assembly that has a GPS hybrid with balls much like a BGA. This is a RoHS assembly using no-clean solder (Kester EM907). The voids are at or above 25%. I use an 8 zone oven where I peak in zone 7 and use zone 8 as an extended peak. I've tried RSS and RTS profiles with no change in the voids. I've tried following the profile recommended by the paste manufacture and profiles recommended by the GPS hybrid datasheet using an ECD Megamole 20. I contacted the GPS hybrid manufacturer and got the following response: "Since the soldering pads

How much voiding to allow on QFN's

Jan 12, 2010 | How much voiding to allow on QFN's What is your concern regarding voiding in QFN solder connections?

LGa soldering issues......

Aug 26, 2009 | we found: Manufacturer recommends 1:1 stencil with a .005" foil. We tried 1:1 with excessive bridging. Knee jerk reaction, we cut a new stencil with a 30% reduction. No voids but the solder would columnize between the PCB and part. We cut a new stencil to a 15% reduction and we saw a decrease in bridging and full wetting of the pads. We found that this part was prone to voiding. We also found that after the reduction, any bridge found was associated to a pad with a large void (displacement of the solder) Rework: We purchased a component print frame stencil. We stencil the part, reflow the solder on the part, and then place it like a BGA. So far we have a 100% success rate So reduce your stencil slightly, adjust your profile to minimize voids For rework, pre-bump your parts with a component print frame then replace. Is this a high volume application? If not, I would reduce the paste volume deposited

QFN Thermal pad voiding

May 30, 2009 | QFN Thermal pad voiding to use the full extents or capacity of the QFN. HAHA, They will of course reply with: Yes we do! Don't believe them! For ex. QFN 9x9mm or QFN 5x5mm with 9 vias or (whatever nr) in the ground pad, pcb thickness 1.6mm => make 4 square rounded corner apertures on the ground pad and the total reduction of 20 % (80 % solder paste). Then you still be able to solder the terminals around. Don't worry to much of the void's. Just following my tips and you will be fine. The X-ray will always complains about voids in this particular matter. There will always be voids. I can safely say, after our customers

QFN Thermal pad voiding

May 15, 2009 | QFN Thermal pad voiding Hi all, Is there any standard for percentage voiding on the center thermal pad on a QFN? We use the dot matrix array for paste to allow for outgassing etc, but we have had a couple of xray inspection "fails" for voiding on this pad , in or around 30-40% voiding. Is this not normal considering its

BGA voids

Apr 27, 2009 | Remember that the 25% is a reduction in cross sectional area. A void in the middle of the ball that reduces the cross sectional area by 25% is about half the diameter of the ball. If it is closer to either termination, the corresponding size would be less. You really should put together some BGA voids

BGA voids

Apr 23, 2009 | BGA voids During initial profiling we shoot for 15% or less voiding on our BGAs. During production runs we consider voids under 15% to be ok. Voiding between 15%-25% we string tag and pay more attention to during test. Over 25% we consider a reject.

BGA voids

Apr 23, 2009 | BGA voids Every paper I've seen published shows that BGA voids either have no effect or actually give a slight improvement. The one exception are voids with a root cause in bad incoming boards, such as champagne voiding where nearly the entire interface is gone. I've done thermal cycling of BGAs(-40/+125C and -40/+150C) and found voids had no measurable effect on reliability, including voids up around 35%. I have no idea what the words "process indicator" means in this context and wish IPC-610 hadn't used them. If voids aren't a defect, what are they indicating? Why would I monkey with my process

Voiding In BGAs

Nov 4, 2008 | Voiding In BGAs Anyone have any advise on reduing voiding in BGAs using a SAC305 solder paste?

Solder voids in PTH

Feb 19, 2008 | Solder voids in PTH Do you of reducing hole size of DIMM connector will improve solder voids??

BGA Voids

Feb 13, 2008 | BGA Voids Larry, from my days of working for a Telecom. company, Bellcore standards (now Telcordia) was our BGA Void guideline. There was some verbiage in the guideline that accounted for allowable VOID VOLUME ...keep in mind, VOID AREA and volume are 2 different things. The 2D x-ray that we used measure void AREA (not volume). That being said, we took the area measurement, and coverted it to volume - example 13.5% area void translates to 5% volume void (it's all from your high school gee-i'm-a-tree class). The QE's in your company will love this. See attachment for details. (THANKS SMTNet

Voiding in Underfill process

Jan 21, 2008 | Voiding in Underfill process Is there a tool to check for voiding in a Underfill process?

Germanium doping of SN100

Dec 18, 2007 | A google search on his subject brings several reports on the effect of germanium on LF solder, notably reduction in bridging and icicles, better wetting and reduction on dross production.


Sep 17, 2007 | Void We have never studied this, but here's what we'd guess. If there are void in BGA solder balls at inbound: * A proper reflow recipe will eliminate the void. * A poor recipe will allow the void to remain and possibly generate additional void.


Sep 6, 2007 | Void Can voids be carried over from original voids in solder balls during reflow?

Reflow issue with QFN

Jul 13, 2007 | It sounds like more has to do with plating. you may also check out the voiding issue especially if you have new FAB or the supplier. I had problems with a RF chip in QFN package due to insufficient grounding that voiding caused. This ground is often used for heat relief as well. The recommendation is min 80% solder coverage by area. QFN usually requires paste reduction to avoid open joints. It depends on the via on the pad and solder mask. difficult to avoid via if the via are plugged on bottom side due to air entrapped. I find it works good with no plugging on the via holes. Good luck! Sean

Solder beads on small caps and res.

Nov 29, 2006 | I have used a 10% area reduction with home plates on 6 mil stencils with good success. If you're using 5 mil stencils you might go with 0 or 5% reduction.

SAC solder balls reflow with Sn/Pb paste - Voids Issue

Oct 6, 2006 | Here's the BGA voids-reduction profile that I used: http://img323.imageshack.us/my.php?image=profileka0.jpg Keep in mind, this was for Sn/Pb BGA with Sn/Pb solder paste. For your situation, you SAC solder balls reflow with Sn/Pb paste - Voids Issue temperatures will successfully collapse and "coalesce" your BGA solder joint, as long as you've spent at least 30 seconds above 217*C (SAC's liquidous point). Whether they help your voids, give it a try!

Imm Silver and Voiding

Jun 22, 2006 | First, we expect voiding in imm silver to be similar to ENIG. We expect more voiding in OSP than other common solderability protection. Second, choosing a solder paste, which does not contain resins and activators that decompose at higher temperatures, is the primary factor in void reduction Imm Silver and Voiding . Third, tell us more about your: * Solder paste * Thermal recipe measured at voiding site * Breadth and scope of problem

Solder Paste Voids

Nov 23, 2005 | Solder Paste Voids Search the fine SMTnet Archives for background on BGA void, while you're waiting for others to respond

Voiding under BGA's

May 10, 2005 | Voiding under BGA's Dr Lee at Indium has written extensively on voiding, Check their site for papers.

Pasteproblemater aftersoldering

Feb 8, 2005 | have you had any reduction in aperture size though, we generally use a 6 mil stencil thickness with a 10% aperture size reduction for chip components and leaded components ( SOIC - QFP ) and a 1:1 ratio for BGA components without any problems.

BGA Specifications for IPC Class

Feb 2, 2005 | Based on X-ray imaging, IPC-7095 standard specifies three categories for void size for BGA solder joints. These categories are based on the percentage of joint cross sectional area occupied by the voided area. Class III Small: Void area is LT 9% Class II Medium: Void area GT 9% but LT 20.25% Class I Large: Void area GT 20.25% but LT 36% This standard does not specify a category for voids GT 36% and assumes that is beyond acceptable limits of most products. Class III product would be for highest reliability with the smallest allowable void area.

Long Soak Times for BGA soldering?

Jul 5, 2004 | Hey, this is something that I've looked at and published a paper on back in 2003 at Apex, actually pert of one, the other part was lookign at how effective X-ray systems (lamanography systems) were at detecting & measuring BGA void size accuratly (conclusion... erm... no not really they is around the reduction of the flux volatiles at the 1st level i.e. those that burn off between 120 - 160 deg depending ont he particualr chemist developing the solder paste and company... mostly they will not give you a definate time / window as you can reverse engineer the paste from that. The burnign off of the flux will reduce the amount of gassing occurrign during reflow when the solder ball / paste is molten adn will infact reduce voiding int he devices. (not the selection of sn/pb or sn/pb/ag pastes vs ball material will also increase or decrease voiding) The other side is that when you take the board

LSP profile

Jun 7, 2004 | First, voiding is a process indicator. Next, as you say, the profile is a significant contributor to void formation. Finally, when considering the "material factors" that drive void formation, solder paste formulation is the most critical. Discussing voids is one THE most favorite topics here

Large Voids with Via in Pad

Apr 13, 2004 | Large Voids with Via in Pad Now, that's different. We misunderstood the problem from your original descrtiption. We thought the voids were showing at the via in the pad. Now, we understand the voids appear to be in the solder balls. Suggestions are: * Search the SMTnet Archives. * Get some of the papers published by Dr . Lee at Indium Corp. He has conducted a number of investigations concerning solder joint voiding and BGA components. * Following from this previous comment, recognize that solder paste composition is a major contributor to BGA voiding. * That voids disappear when you rework them with hot air, may

Large Voids with Via in Pad

Apr 13, 2004 | Large Voids with Via in Pad The PCB's we are seeing the voids on are made of some material called Thermount, not FR4. The pads are very easily pulled off if any touch up or rework is done. The voids I am seeing are (hugh) 50% to 75% of the Solder Ball volume. The last new batch of these boards we just ran had almost no voids at all. If the did the voids were very small. Thanks to everyone for your comments.

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