Order by: Relevancy | Date
Jul 25, 2001 | Solder Paste As Dave said you should be concerned about separation. If you open the jar and see that the flux has separated from the paste ditch it. I guess I am a little more hesitant than others, I would discard the material and use fresh. You have to way the costs a jar of paste vrs the possible cost to touch up or rework the brds if you don�t get good wetting or a poor joint.
Dec 5, 2005 | thermal cycling chemical reactions (can occur slowly) they were only touching before and not really a solid solder joint BGA ball Separation
Sep 1, 1999 | Re: Solder Joint Integrity | Dear fellow process engineers, | | Some solder joints "trough hole component" have cracked. I suspect that in the market some technician tryed to straighten some components (LED) and has applied enough force to actually brake the joint. The joints were broken (lifted of the pad)in a nice round fashion which indicates mechanical force. The surface of the pad was still covered with solder. | | I now have major arguments with our "star designers" which insist the flux (Multicore NRS-06 VOC free) is not doing his job. | In other words the solder separates from the track. I argue
Aug 31, 1999 | Solder Joint Integrity Dear fellow process engineers, Some solder joints "trough hole component" have cracked. I suspect that in the market some technician tryed to straighten some components (LED) and has applied enough force to actually brake the joint. The joints were broken (lifted of the pad)in a nice round fashion which indicates mechanical force. The surface of the pad was still covered with solder. I now have major arguments with our "star designers" which insist the flux (Multicore NRS-06 VOC free) is not doing his job. In other words the solder separates from the track. I argue
Feb 9, 2000 | I have seen an issue that escapes our ICT and functional testing or operates in an intermitent fashion. The lead is slightly separated from the PCB with a fully formed solder joint behind it at the heel an toe. The joint apears to have started to travel up the back of the lead and under the lead , but appears that it didn't stick. The joint is shiny/smooth on the sides and under the lead. We have done steam aging, x-ray florecence, and solderability tests on PCB's and parts and we have found nothing. It is a less than 1% issue, but we are dumbfounded on what will cause such a condition. Any ideas????
Jun 19, 2000 | Mike: Look a the Hadco DFM manual ( http://www.hadco.com/ ) Yano if you�re lookin� for uniformly smooth (not silky smooth) board edges, have you considered scoring to separate your boards? Scoring has: * Minuses (straight lines only, stress on solder joints close to score, additional operation at PCB fabrication, and edge of PCB is not smooth) * Pluses: (leaves sorta smooth surface, increase panel use, ease of separation, and better in assembly). Look at scoring in the Hadco DFM manual also.
Sep 22, 1998 | Hi Jacqueline! Do these joints that you're having problems with happen to be on fine pitch solder joints? Are the fillets staying attached to the foot and separating from the pads cleanly? If that is true, are there many vias concentrated around the QFP footprint and attached to the pads by a very short trace? If that is true and the board is being wave soldered, then what you have is that the pads are becoming hot enough to almost reflow the solder joints again when passing across the wave, and losing the original bond created from the initial reflow. The boards need to be corrected transfer during wave that causes those solder joints to lose their bond. I hope this helps! -Steve Gregory-
Dec 10, 2008 | plate for these areas. We've experienced the problem that you've noted; but, for us, the fix was to add no-clean flux separately. My solderers typically try not to add flux when soldering no-clean, and try to only use the flux contained in the solder core. For tough to solder joints, the answer has almost always been to use a separate flux on the joint. You may also consider increasing the iron tip temperature, and ensuring that the solderer stays on the joint long enough. One thing I've found with solderers switching over to lead-free from leaded solder is that they're resistant to staying on the joint longer. To keep the tip temps as low as possible (to minimize damage to parts or boards), we've found that solder time is increased, due to the different performance of the lead-free solder. cheers ..rob
Jul 2, 2009 | thanks kpm. agree the cause of those pads lifting. all of them were no connects so they cannot be the cause of the electrical failure. when the bga was removed, all the solder balls on the pcb turned into conical shape due to the separation, except for two balls (which appear to have flat tops ) in one corner of the board. the corresponding two pins on the bga package also showed flat irregular solder. that seems to indicate that those two pins did not have a good solder joint. could that have been due to head-in-pillow defects at assembly, or broken joint after assembly? the board came back
Sep 22, 1998 | | Hi Jacqueline! | Do these joints that you're having problems with happen to be on fine pitch solder joints? Are the fillets staying attached to the foot and separating from the pads cleanly? | If that is true, are there many vias concentrated around the QFP footprint and attached to the pads by a very short trace? If that is true and the board is being wave soldered, then what you have is that the pads are becoming hot enough to almost reflow the solder joints again when passing across the wave, and losing the original bond created from the initial reflow. The boards need prevent the thermal transfer during wave that causes those solder joints to lose their bond. | I hope this helps! | -Steve Gregory- Steve I have had that problem also Whereas the joint looks great, but you can move the pin left and right and the solder joint is attached to the leg and not the board
Jan 18, 2000 | It makes a difference what the normalizer is. We calculate solder ppm and placement ppm separately for each assembly. Solder ppm = #solder defects*1E6/(Qty boards*#solder joints per board). For us this number is easily less than 50 and sometimes <10. Now do the same calculation for placement defects using the number of components per board in the denominator. For us this number varies much more than the solder ppm. Our best numbers are around 200-300ppm on a board with 900 components and 3000 solder joints. I have seen bad runs where ppms jump to 2000. All of our data comes from AOI. I
Sep 22, 1998 | | | Hi Jacqueline! | | Do these joints that you're having problems with happen to be on fine pitch solder joints? Are the fillets staying attached to the foot and separating from the pads cleanly? | | If that is true, are there many vias concentrated around the QFP footprint and attached to the pads by a very short trace? If that is true and the board is being wave soldered, then what you have is that the pads are becoming hot enough to almost reflow the solder joints again when passing across the wave, and losing the original bond created from the initial reflow. The boards need prevent the thermal transfer during wave that causes those solder joints to lose their bond. | | I hope this helps! | | -Steve Gregory- | Steve | I have had that problem also | Whereas the joint looks great, but you can move the pin left and right and the solder joint is attached to the leg
May 12, 2014 | stencil, and hand solder that part as a separate process. Stencil change is probably best, but I completely understand not wanting to change them (all) out. Best of luck, let us know how you solve this! 'hege Solder climbs on the lead and touches the body of the component It sounds like a bit too much solder on the PWB, caused by too large a pad for the lead it will contain. In that case solder reduction is the way to move forward. What are the options there? 1. New stencil or stencils - (not desirable) 2. Increase blade pressure at print to reduce solder print
Dec 5, 2005 | BGA ball Separation Ina ddition to the above it can be from CTE mismatch and the joints are breaking during cooling. Is this an Altera part?
May 22, 2003 | line making sure those comps don't exceed the thermal shock point, and lower than a cold-solder joint point. Good luck. The alternative is by looking at all your components data specs (heat-range), especially pay more attentions to heat-sensitive comps, and fine-pitch comps, odd-form comps, draw a diagram on a separate sheet of paper shown that temperature VS those catagories comps at the same chart, draw 2 limit
Jan 29, 2002 | lead coalescence in solder joint Over-time lead separates from the tin in solder by force of nature [diffusion], but I assume that is not what you are talking about. Please help us understand your question better. Are you saying that the solder does not attach properly to the component termination or the conductive pad on the board? Please describe the problem in more detail by telling us about: * Type of solder you are using. * Soldering method. * Distribution of the problem across this product [ie, all solder connections, some connections, etc.]. * Distribution of the problem across all products. * Component where you
Nov 8, 1999 | . The fixture was a jointed frame that supported the board and prevented any warping during the separation. Separation was accomplished by simply bending the frame at the joint (we put little handles at the top). This also works for the breakaway tabs you mentioned . Hope this helps. Brian Oh boy, does that bring back memories!!!!! You are most likely breaking components when the board is flexed during separation. Any components perpendicular to the score are candidates for mechanical stress. We overcame the problem by making our own "pizza cutter" and by making fixtures
Sep 4, 2003 | The typical PIP process is incorporated into the surface mount process. This approach requires the following: The stencil will be designed so that the correct amount of solder paste can be printed onto the through-holes to form an acceptable joint after reflow. The solder paste will be amenable to the PIP process. The stencil printing process should be optimized. Through-hole components will be selected so they can withstand reflow soldering temperatures. Leads should be rounded at the end and be the correct length to form a good solder joint. Through-hole components will be mounted correctly . The reflow profile will be acceptable. The stencil must deliver the correct amount of solder paste to the through-hole during the stencil printing process. To achieve this goal, the amount of solder needed must be determined. The volume of solder in the through-hole solder joint, VSJ equals the volume
Oct 24, 2002 | that were good will either show normal solder gray coloring or in many cases actually pull the Cu PCB pads out and show copper color. There are numerous reasons for open joints on BGA. PCB pad Ni/Au separation, non adhesion to the applied solder on the PCB, intermetallic fractures at the BGA substrate connections. After injecting the dye, cure in a bake oven at 100C for 30 minutes. After curing, flex or bend the PCB in order to break all of the good solder connections. After breaking the good connections, pry off the BGA. Any solder joints or traces that were originally open will show red. The joints ="_blank">http://ap.pennnet.com/home.cfm I can give you a summary explanation. Dye penetrant analysis is a technique used to find open solder connections and fractures on devices such as BGA and DCA. It's a relatively simple technique which involves injecting a red dye, such as ITW's Dyekem DX-296, under a BGA which has suspect solder
Jun 14, 2000 | Re: solder joint problem? with very little force until it separated from the pad ( with a good solderjoint you would normally separate the pad from the PCB by doing this ) - the malfunction of the boards occured during first test or after a couple of days in the systems. - additionell handsoldering solved the problem. The problem was an improper reflow profile they used and it was suspected that an reoxidation took place due to too much oxygen blown into the joint by their equipment. They never told us what they did actually and I suppose they didn�t know what they where doing wrong. In addition the leads had a gold finish
Nov 17, 2005 | of hand soldering could degrade the interconnection quickly. We'd expect heavy handed use of soldering irons to lift pads or crack inner walls, rather than cause inner layer separation. Inner Layer Separation from Barrel Wall - Too Much Heat? We're with your customer. We believe inner layer separation is not linked to a heating excursion. What you are seeing is separation between the hole wall and the copper plating in the barrel of the hole on an unstressed PTH. Although, it's possible that the stresses from the thermal excursions
Mar 9, 1998 | ;lifting" of the connector. Also connector contact may cause separation of the solder bead before solder joint formation and thus cause extraneous solder balls and starved solder joints. The generally the solder paste from extended overprint should coalesce with minimal extraneous solder balls provided that you have good Re: Any help reflow soldering Through Hole parts | We have a double sided pcb that is surface mount on both sides. Now a Through Hole connector has been added. Appart from hand soldering does anyone have info. on reflow soldering the part. The connector is 0.1mm pitch, square legs. | 1) Do you need to change the hole pad, shape. | 2) Do you
Jan 29, 2007 | Thanks Russ and John, To clarify defects when manufacturing a PCBA, I use (2) groups of defect categories, one for components and one for solder joints. These can be calculated separately or combined A component defect could be: Missing, Miss-aligned, damaged, wrong, polarity, Etc. A Solder joint defect could be: bridge, open, insufficient, excessive, etc. For overall combined DPMO I simply sum the component and solder joint counts, the combined sum would be the opportunities. DPMO is calculated by (sum of defects / sum of Ops)*1,000,000 = DPMO. This can be performed by PCBA, all
Jun 25, 1998 | Re: Solder Joint Problem Hi there Chris! Are the leads you talking about fine pitch? Is the complete fillet attached to the foot, with it being cleanly separated from the pad? I bet if you look at the board there will be via's really close to the pads at the locations where you're having problems. If that is the case , what is happening is you're getting re-reflow (no, I wasn't stuttering...hehehe) when you're wave soldering the board. You're getting heat transfer coming thru the via's when it hits the wave and because they're so close to the pads, bingo- bango...you got the opens you're having. If the via's don
Feb 17, 2006 | Hi, I take it you are refering to intrusive reflow? It came around as more components became available in surface mount packages leaving mainly connectors left over for a separate insertion operation & wave/selective/hand solder. Manufacturers improved the thermal properties of their plastics allowing connectors to withstand reflow profiles, and paste was put down via 3D stencil, solder preform, dispensor etc, around & in the holes. Then the paste down the hole to form a reasonable joint. Take a look at Bob Willis' website, he always has something useful to say:
Feb 20, 2001 | .Because recently we have customer complaining of solder joint separating form the BGA and solder ball interface while stay firm with the pc board.
Jul 2, 2003 | Not sure how else to describe this. We've received some boards (1/2" x 3.5" x .0325" board built on panels of 24) with numerous resistors showing separation of the solder from the metallization at the top of the joint. There are 26 0805's on the board (about 1/2 are resistors, half caps) and all solder fillet peeling
Dec 3, 2002 | pics. Solder is beautiful. Joints look great and the wetting angles are dead on. Method used to depanel the board and distance damaged capacitors are from the board edge: On the first 4 builds they (lab) depanelized (for cross-section prep) with a band saw. We asked for a diamond blade on the last I don't think I can post pics in this (if anyone knows otherwise let me know), so I will email them to anyone who's curious. Here's the answers to your questions: Placement Force: 0201s are placed on the Siemens S23s with 1 newton of force. The separation is at the metal to substrate so I in the area of the 0201s. Cooling rate of the Reflow recipe: The cooling rate of the laminate is 2-3 C/sec. The cooling rate of the air is 4-5 C/sec. I can slow it down more but according to the component manufacturer we are well within spec. How the solder connection to the metalization appears: See
Jan 17, 2001 | . Like to understand the cause for the differnece. 1.During reflow, when the ball melts, does the ball separate from the BGA? If yes Where does intermetallic layer stay? In the molten ball or the pad? 2. Can the flux from the solder paste flow to the BGA's Pad during reflow? 3. Does this flux play a role in "remaking" solder joint made betweent the BGA's substrate and solder ball? 4. Does this SMT reflow degrade the shear strength of the joint between the BGA ball & BGA laminate after SMT reflow? 5. What is the metallugical characteristics of the NiSn Intermetallics? What is the melting point We have few failures similar to the discussion in this thread, on a 50 Mil pitch, 30 Mil mill Ball PBGA. Would like to understand the mechanism of the BGA reflow process bit more. Appreciate your response to the following. 1.We sheared few solder balls from a raw BGA. We sheared a BGA laminate
Jun 21, 2017 | but we do not have laminate preheating on robots. There is no flux separate application, the flux is in the soldering wire Soldering robot and solder balls
Feb 13, 2006 | not changed part numbers for lead free. Don't forget to apply the same principles to your manufacturing stock, such as iron tips, solder wick, etc. Keep those totally separate or contamination can occur. Hope this helps, Brian We have a joint process with our purchasing department. They get notification from a supplier, which is passed to us. As a CM, we notify the customer and get permission to use it. Then we enter a new part number with a special suffix indicating lead free. When the old stock becomes 0, we change
Mar 20, 2006 | Fighting solder beads Good morning, In this case separation speed doesn�t affect print quality. Separation speed decrease makes print quality the same or worse. Apertures still remain blocked. Any ideas? Thanks. BR, Pavel
Aug 24, 2005 | I think where the fuzzy thinking starts is by calling the recipe's; profiles. Or maybe I"m being too fussy. Idealy you want every solder joint to have the same thermal "profile" (not recipe). That is the temperature over time is best if identical for every joint on every board. You can't do that of course because every different component (and PCB) has different thermal characteristics. This means the recipe gets changed. (and I internaly cringe when someone says use a new profile) Changing the recipe does change the profile but they are two separate entities. The second source of fuzzines is Temperature vs Heat. You want the same temperature exposure for every joint. But different comps have different thermal characteristics. This means to get the same temperature exposure you need different heat exposures. WIth big heavy BGA's they can soak up a lot of heat. Therefor you need a slower belt
Apr 23, 2004 | Hi all Does any one know problem with solder joint call crystallised joints. I have noticed that sometimes on our PCB when i look at the joints for example chips, LCCC, there are areas not smooth solder (very often in the center of the solder joint) but near solder pad and near components end solder is smooth and ok). Our process engineer said that it is crystallised joints but not effect the joint quality and it is cosmetic defect. Any comments ? Robert Crystallised Joints
Apr 16, 2003 | of the volatiles in the paste. Or it could possible be the opposite and you are drying out the flux before reflow. I would recommend verifying the profile to your paste mfg. recommended, ensure that you are using good paste (date code, non-separated, etc). you can expect to see some voiding in solder joints Voids in solder fillet . You want to try and achieve a solder fillet that extends somewhere around 1/3 to 2/3 of component height. What could possibly be happening (i am thinking out loud here)is due to the large amount of paste applied the soak temp and duration may not be high and long enough to drive out all
Nov 17, 2005 | We have a board that has been diagnosed with inner layer separation from the barrel wall. This board is .093 thick and 12 layers. Several layers, in some cases, have little or no thermal relief making soldering difficult. We have since switched to PIP for the parts in question and that has taken care of the soldering problem but the early units were hand soldered. We have cross-section photos of the separation so there's no debating the symptom. The customer is convinced that this is a raw fab issue but I wonder if we may have overheated these early units (using irons Inner Layer Separation from Barrel Wall - Too Much Heat?
Jan 17, 2001 | >We find that the raw BGA's pad sheared surface has the SnPb solder at various Z heights whereas the assembled BGAs pad leave a smooth layer of SnPb along the pad. Like to understand the cause for the difference. Who could guess? Solder joint strength in pull/shear varies with lead geometry melts, does the ball separate from the BGA? Which reflow? What kind of balls? What pads? What pad solderability preservative? What solder? Hel-low-oh!!! When soldering the balls of a BGA to the assembly, I expect the ball to remain wetted to the [nickel plate over???] the copper pad on the BGA interposer. With a PBGA, like yours, I expect the ball will melt, collapse, and wet to the solderable surface on the assembly PCB. If you find the balls separating from the BGA, something is wrong, either with the BGA fabrication process or your material selection / process control. > If yes, where does
Aug 28, 2000 | the two and bridging can occur. Also legend ink should be considered. It could impact the flow of solder causing separation forming SOLDER BALLS. 3. Effects are limitless ; that�s why there is a forum to ask questions! 4. Sorry MoonMan ; PCB design is not my specialty, maybe you will enlighten us all joints during temperature cycling. Cracks form and propagate in the solder joints until the joint is entirely broken, resulting in electrical failure. The columns of CCGA�s are more ductile allowing for stress relief. 7. SMQ92 Solder Paste: I have no idea, Share the knowledge MoonMan. 8. Tg and TCE MoonMan, I'll take a crack at the list. Feel free to answer the ones I don't! 1. Solderability is a parameter which indicates how well a component can be soldered. As far as Solder Termination Coatings go, here are some up�s and down�s of a few. Hassle: A solder coating over all exposed pads
Apr 29, 2011 | will be directly below the surface of the nickel by leaving both nickel and phosphorous (a normal constituent of electroless nickel) on both the pad and the failed solder joint surface. "Black Pad" is a defect related to ENIG boards. It is a separation of solder joints formed to the surface of the electroless Below is the long explanation. This defect is most commonly found with BGA components, but can arrise with all components. I see it happening more now with lead free boards that are being assembled with a no clean flux. Best short term remedy is to touch up the affected solder joint, and or SM nickel plate. This is because the immersion gold is so thin that all of the gold dissolves into the solder upon soldering. The solder bonds directly to the electroless nickel. If that nickel surface is contaminated in some way, the resulting joint will be weak and the location of failure
Feb 24, 2017 | Does pot temperature affects quality of the solder joints? Selective Soldering Frames can pull large amounts of heat from the solder wave at the point of contact, effectively lowering the temperature of the solder at the solder joint. You should confirm the temperature of the solder joints by running a thermal profile. Once the solder joint temperatures are measured and understood, you can determine if temperature is one of the causes of the cold solder joints. In my experience, cold solder joints were manually created, due to insufficient flux, insufficient heat and insufficient time to create the solder joint.
May 1, 2003 | Solder Joint Microstructure What is the best way to determine solder joint intermetallic composition? Metallography? XDS of the joint? Any input is appreciated.
Jun 25, 2004 | Grainy Solder Joints The potting definitely is a factor in fracturing the grainy joints, but does not seem to damage a "good" solder joint.
Sep 21, 2005 | go beat the designer over the head until he separates the pads or uses solder mask.
Aug 5, 2004 | joint separation. BGA open joint Agreed. Joint failure can happen when un-bagging or durig box-build (at customer site). Careful handling should be used. In one case I had boards returned to me for evaluation and failure analysis. Too bad our site never built the boards!!! (jackass customer gave me hell about our quality
Jun 3, 2004 | We know of two "solder savers" 1 Kester Formula 5749 Solder Saver: We believe Kester Formula 5749 Solder Saver to be a new formulation of Kleenox. Kleenox works. It helps separate the solder entrapped in the dross. [One tiny warning, one chemical byproduct of the Kleenox dross reduction process of the solder wave pot. The dross oxides are instantly separated from the solder using a unique high-speed rotary process system. The newly separated solder flows back into the pot whilst the oxide powder is deposited on the solder surface, for easy collection and removal. [Pulsar Solder Saver +44 (0) 1 383 824 Solder Saver
May 11, 1998 | are connected to an internal power or ground plane and not thermally relieved, the internal plane acts like a heat sink and causes the solder to freeze and solidify before the solder has a chance to separate cleanly as it's exiting the wave. When was the last time you had a solder analysis done on yer' pot ? It doesn't take a whole lot of contamination of other metals to make the solder behave weird. Just a little too much copper, aluminum, etc. can change the liquidous point and viscosity, not to mention the grain structure of solder joints. Just out of curiosity, what kinda process are you in, no
Jan 7, 2004 | The cause of cold solder after a drop test => Cold solder prior to properly performing a well designed drop test. Actually, "cold solder" means different things to different people. Two dull solder connection conditions are: * "Disturbed" solder joint: a solder joint that has an "angular faceted " appearance that is caused by the solder joint being moved as it solidified. * "Grainy" solder joint: a solder joint that has a rough, gritty appearance that is caused by the solder microstructure giving the solder joint surface relief. cold solder after drop test
Jul 3, 2013 | reflow solder joint shear strength How to test the reflow solder joint shear strength? What are the specification to test solder joint shear strength? What are the different methods to test the solder joint shear strength? Vijayashree
Jan 21, 1999 | common causes of open solder joints on PBGA's are secondary wave solder opens, due to the PBGA spheres remelting during the wave process, and intermetallic separation when BGA's are soldered on to electroless nickel/gold plated board pads, due to phosphorus which is used in the nickel plating bath without pushing down on the package. This measurement is typically performed with automated laser scanning machines. Since the PBGA substrate is made with a BT resin, it's glass transition temperature is 170�. PBGA substrates will relax at temperatures above 170�, and be flat during soldering. The most
Jul 1, 1999 | | Dear guys, | | I have some problem on assembling micro-BGA with solder paste (63/37). The micro-BGA we assmeble is 0.75mm pitch and with 45 pin (solder bump is 96.5/3.5Ag). The stencil is a laser-cut stencil with 5 mil thickness. We are now using a no-clean solder paste, with the metal mesh easily; or | (ii) use size 4 powder. | | Is it really help? DO you have any experience on assembling micro-BGA with solder paste? | | Thanks in advance. | Vic We had release problems when we tried using circular apertures on the stencil. While releasing from the stencil, the brick would pull up around the edges making the brick much taller. I altered the stencil apertures for the BGA to make them square and cut down on the size of the square to match the volume of the circular pad. We got better separation from the stencil and a much more repeatable volume. The corners of the square actually
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