PCB Manufacturing - Important facts you should know

hi guys my name is Robert ceramic high from Fandral Academy and in this video we are going to speak about PCB manufacturing basically why I created this video it's because when you are designing balls I think it is very useful to know some information about this demand of actioning and I had this opportunity to visit Serie C script company they do a couple of different things a lot of the things they do is a PCB manufacturing and during my visit I recorded couple of hours of video from this couple of hours I I created I think around 19 short video clips about the most interesting topic which I really found like wow or all the topics which I think you can find interesting or you can find useful and maybe you can learn something new from this and I'm telling you even I didn't know some of the things just to give you an idea what is going to be inside of this video and I'm I'm going to make a small piece so you don't go away I didn't enjoy the video this is what will be some of the clip them out the first one is going to be dull drilling and the interesting fact what I learned about the drilling is with six mill drill bit you can only drill hundred holes Wow this Vipassana if you are designing board and it is not necessary to use six mil drill bit maybe you don't want to use it because it can make your PCB cheaper the other thing what I found interesting was this layers of pacific and move and shrink during PCB manufacturing so you know when they build multi-layer PCBs and when the laminate them when they heat them up and bake them then the layers during this process I can move a little bit that's okay I was expecting moving actually inking I didn't know layer of the Pacific and shrink and the first thing what I found really interesting from all this clip I'm going to show you is that copper can grow between holes drill too close to each other so one of the reasons why you cannot drill the holes very close to each other is because the copper can grow between them we will be taking about this okay so watch and you will see a little bit later before I start the first clip I would like to say that the clips were recorded directly inside the company so in some of the clips there is really strong sometimes even disturbing background noise I try to remove it it didn't go very well so I just like the background noise in the video you still can understand what we are speaking about just be prepared okay especially in this first video clip the background noise is really strong so let's do it let's watch the first video clip so drilling area and so chilling is the most costly four main factor mm yeah because they're drill bit every drill bit that you use you're only using a certain amount of time and then you sort of way and that group it is very expensive so just for some kind of illustration how many times you can drill approximately I know there's no drew you can only understand every time is point six mil - I saw like if they like 10000 or no hundred that's why they're very expensive so if you have a good Sentinel hole because Esau so six meals a star 0.15 or zero point so normally is much better if someone won't trip repeatedly use 0.2 it's all quiet now so next time when you are designing a board be careful about the minimum size of the whole picture use on your PC me I think if you would like to go for the cheapest PCB in China usually the minimum hall which they recommend is 0.3 millimeter that's 12 meals okay anything below 0.3 millimeter is going to probably increase the price of your board in the next clip we are going to speak about the sliver something like what you can see here and also we will speak about this kind of situation when you draw a track like this out of the path under this shot angle here from my experience I never had any problems with this kind of connection but you will see I will mention that sometimes it may become a problem so it is the second clip they check for something called slivers so if you have an island of copper that's not that or something that could become an island of copper during the etching process the problem with that is that those pieces of copper they end up coming off of the material and falling somewhere else on the panel during manufacturing which is of course a short or an open now for sure so can I go United anything yes I believe I can do it likely this would be the path and yeah please have it resolved yeah and they say state is problem because I don't live abroad so you go and do the Anglesey with this was a short clip about flavor and now we are going to speak about tear drop if you are not sure what the drops are I'm going to show you okay what's here we are trucks you go here to the drops okay see this here this copper additional copper here it's called T drops they sometimes do it specially when this annual ring is too small they do it because in case of moving or the whole yeah the whole can be moved because the layers are moved or because of the drilling clearance it is hole it moves a little bit up here for example here then if you use these T drops the connection steel will be okay if there is no T drop and you drill the hole like here you basically cut the connection this is what is the next clip about and okay what about these drops many people ask about tear off so do they need to do it in in the layout or you do it here or why you do it yeah we correct for tear drops so tear drops are important because of the drill trip position and role wander so if you are drilling a hole in a pad without a tear drop you have less let's say leeway or less tolerance and if your drill bit happens to land where the trace is hitting the tag you could literally cut the connection or completely but it's not necessary designers do it you will not necessarily will correct for that okay one of the things we do in camp the teardrop is there something special about these rocks what they you know some engineers they asked me they would like to edit you just editing that there are no special requirements for these rocks they need to be called every track or nothing special how big they need to be no special designer punishment eardrums just put it message in this case I add the table you see here getting violations so I can add your brother okay that what you do then we don't have to add or we need this is enough when you're excited at allit it is the distant by mail you would like to add the address mm-hmm the important information from this video is the side meals unloading yes if you would like to have easy PCB manufacturing then keep unrolling the distance between this edge of the hole to the edge of the path this mr. hit keep it bigger than 5 mil if you make it smaller than 5 meals then yeah it's becoming more and more difficult for manufacturing in the next clip I just learn new world so I included this clip because it's interesting you will learn what does it mean to when people say H comp H compensation the filtration sphere is what we do every board job does this will take the trays in space and they'll take a trace and they'll add copper to it so that's edge Conference because when you edge the board the trays goes back down to the tray so that you're looking for so the designer says to manufacture the board as is and my formal traces and my formal spacing don't touch those all we do is we add H comp because that's needed for manufacturing but we won't modify any any of that will that actually result in exact if we model that will that actually result in the undertone differential bizarre looking for the answer's no then what does the impedance depend on so there's three main things that impact impedance in manufacturing one is the edge tolerance okay who is the precise thickness of the dielectric materials and three is how much copper area is on that list okay this was interesting what is in white is interesting many people are why they just cannot simply use this online impedance calculator or the free software to calculate or design the sticker and calculate the impedances is because during PCB manufacturing there are some factors which influence the appellant and these factors they are not included in this theoretical calculations therefore when you are designing a test image which has a specific impedance requirement I always recommend to talk to your PC manufacturer they should send you the final stack up they should send you the recommended tract normally okay online calculator free calculator is for you just to get some idea about the tree geometry and and impedance you cannot get the final numbers from these simple calculators you need to ask your PC in fact in the next clip we are going to speak about moving wires and scaling layers during PC production and we are going to use two words quite often rhetoric and code so for everyone who doesn't know what protect and core means I'm going to very quickly explain a multi-layer PCB how it is built when they build it they use three kinds of materials here on the top you can see it called copper foil so it just gotta yeah inside the PCB here they use something what is called core core is a isolation or be electrical with copper foil on the top and copper foil on the bottom it's basically like a simple two layer PC mini that's what you can see here and when they would like to build a multi-layer PCB they need to put something between the fall and the course or between the course yeah this pod you can see here this something is called rhetoric rhetoric is just isolation there is no copper this has two words that are going to be used in the next clip here it is but I've seen on some PCBs they really like coal perfect car can you do this now yes if you do core prepreg core that's called a book construction and the reason to do that is to control the thickness between layer 1 and 2 okay because that's not changing that's not melting the prepreg in between is what's gonna melt so basically what only males is the Fredrick that's a core never melt right the problem with a book construction is that during lamination the cores can slip out of alignment that's the biggest issue with the core construction so it's not all may sleep out of alignment so it can move a little bit yes so if you have a four layer board and this is core 1 2 and this is core 3 4 so then of any other day oh yeah so one two might go this way three four Michael's that way and then you can't find the best drill area if it slips too much imagine if you have a ten layer board all your core is going to slip a little bit so it becomes much harder to find the true center of all the intersection of all the way all the images and if you if you would like to do the very thin the electrical then it usually done through preference or you can have also very thin car you like 75 micro yet you can do thin course so with a layer four five is in poor you can absolutely do that the problematic part of that is number one edging because the it can get caught in the machine the second thing is that because it's thinner it could scale so that particular core will scale differently to the other course so not only can the course clip out of alignment they can also scale differently so meaning the image itself can shrink at different rates okay so if you have a three mil core and then the rest of your stack up is let's take six milk or five milk or some form of course those materials those layers will move differently than the three mil for the three milk or might shrink a lot faster so basically if you will design a stick up then all the goddess ideally you would like to have same thickness I deal with the all same thickness now the way to get around that resolve that is you process what's called a first article for your facility so now you know how every layer the shrinks and scale then you go back and start over and you scale everything now okay the perfection of what you just they God to production or the production so then now the three milk or should shrink to what you want even though it shrinks at a different rate it'll still shrink to what you want compared to the other course so this is in here this measures how much the cords that move they'd last yes and how they'll know how it measures the electorate so there's a severe show inside the board and so it will x-ray inside the board to see where is that marking they should be on top of each other and it should be yes exactly and so so no not these two but as you x-ray inside you get the idea of the scaling from how far they are you clear and so once you get that then you feel you find your best center hole so if this annular ring for layer two three moves this way and this annular ring for three four years this way now you find the intersection of that Venn diagram so where you drill your body I found this very interesting because this could be one of the reason why PC manufacturers are so persistent when they when they would like to change your take-up if you are moving your production of different pcs manufacture in there are situation when you design a manufacturer your first board with the lamp is the manufacturer and then you decide to move production to different PCB manufacturer and suddenly they would like you to change the stack up and they try to come in to either they'll use their materials and these kind of things and it's quite complicated sometimes and I believe it may be because you know these PCB manufacturer they know exactly how the materials which they use how these material behaves the other manufactures they may be using different materials and they know how these materials they don't want to go through all these procedures where they try to find out how it is going to scale or something like this yeah so be careful when you are designing stack up you really would like to use probably the most standard material usually they can manufacture in China and usually this teacup can be manufactured almost everywhere if you design very specific sticker with specific material you may have problem moving your production between different pieces in manufactures the other clip is very short I'm not going to speak evaluator just watch it and then I will explain plane plane areas video sometime then third in a row this is a variation of quiz but try to the point when I drop outlines so I always make this gap with clearance or difference between the plane wider then in the minimum clearance on the board and I do it one of the reasons why I do it is because I read in some design guide that it helps reduce the noise between the pallet line and as you can see the other reason why you would like to keep this space wide is because of this be monitoring the problem with very thin space is etching if it is very very thin and it's quite complicated to remove the copper between the plane so that's why they need to do it in the PC production a little bit wider it's easy to remove the copper what is also important is the thickness of this cotton picker the copper is divider this gap needs to be okay so keep this in your mind next clip is about 10 millennia if there's nothing special about this terminal area level to the final end ring and at least 8 mil the sleep clearance light meal clearance yes both yes ok hope you have this wonder the channel 10 mil thickness although there are eight to 10 mil yeah notice the members yeah five mil eight mill a to 10 mils because next time when you will be using ten-mile radius in your board you will know what are the minimum numbers which you can use there but the next clip is very interesting people say that they don't do 90 degree scorer because they cause problems during PC manufacturer is this true like because of a Qing of the right angle PCV likes it I don't know what is not true you don't know the place yeah yeah they don't do that you get a phase acting with homages yes never a little aggression little bit crack I think it will cry to say so with you that I like have a 90 and I'm talking about a flexible just like that already booked the next job let's see I really like the radius yeah on the anything and the rigid it's gonna crack - yes okay then that's really in the design and yes okay I hate to ask and you know there are so many discussions on the internet about this 45 verses 19 weekly topic you know if you can route your tracks with 90 degree corner and now it's all you don't need to think about EMI EMC impedance mismatch or I don't know what else just from the PCB point of your PC manufacturing point of view you don't want to route your tracks in 90-degree corners because it may crack and especially if the tracker is very thin or evil your PCB is going to be exposed to some kind of stress like thermal stress or if it can bend or something you really don't want to use 90 degrees corners I never use 90-degree corners but you know I was curious so I asked in the next video you are going to see a line where PCB pH when the copper is removed from the PCB and we are going to speak about a small copper RS copper dots on on the PCB which you can sometimes see I'll have a look about deep dog I want it to us so big dot what we think they were directly on the PCB or the PTO only the small party RPG was only the small okay and when designers are where we are they will not want this to be pocket and if someone is an engineer is designing a typical would you recommend to place the rubric here so you will place it even when I use work they thought I'm not beyond our knowledge it is work even if there is only like very few copper or if there is an extreme example but there is a ten layer board and all the layers are 1 ounce copper and there's like round form and all that is one layer traveling one thing trade right then you should add some cover so he doesn't band or why you have for warpage for scaling again but the more cooperation you have leftover the more ridges that core is if you have only a little bit of copper now the core is not as rigid and the material to move wherever it wants it the war copper means more less movement new cage how the small bolt are called because I played the video couple of times and I everything what I eat is sealing and when I google for PCB stealing I I can't find anything so Eva if you know how exactly this dots on the PCB are called or could you leave me a comment play so you know I learn new world thank you very much in the next video we are going to speak about prepreg about the thermal stress and also about baking PCBs so look this is the material that we melt during lamination to glue the course again and so you notice there's a funny because if you don't use the material right away it's going to flow differently or it might even expire like bad fast food in the fridge if you don't eat it it's like it looks puffy it oh really yeah this is six months so boondocks period you have to use it yeah manufacturer commemorates a single otherwise it won't give you a reliable circuit board when it gets to the final I'm fiction area and we get so bored into hot sauna pot use the four separate okay so here by the way is our are just our flow there you literally dip it into a some solder hot daughter and that's your thermal stress and so the many separation of the layers will find out before assembling as you don't want to spend your board to assembly is fine I've seen these kind of ah so it means something when box I mean the board fabrication with that the other part which is very interesting is that tempest shops they're supposed to bake the board before they assemble and they oftentimes don't do that but alien yeah so if you put a board through with moisture inside of it and that happens normally then the board can separate it doesn't mean the board's about maybe the family shop didn't take therefore so when we do our fabrication assembly close together there's no need to bake the window you'll need to bake it when it so or anything four hours okay works 24 hours the board sitting around you should bake them before you assemble because of the humidity as communities moisture gets trapped inside and that's it so baking in tournaments today I know exactly what thermal stress means because I'm going through one right now here like 200 degrees it's all hot but I will do it I will finish this video for you no I'm just kidding no I'm not kidding it's really hot he knows in the next clip we are going to speak about drink and I think this information is quite interesting that's why I included the cream and a look if you have a two layer board the first thing we do is we'll take your for the drilling and then we image initially around when you have a multi-layer board you imagine as all the inner layer cores you laminate the outer layers which are foiled and it essentially looks like a two layer board now and then you go to drilling and drill it and you go an image drilling is always before we images so you can image URL and drill yeah what do you think why I included this clip in this video it's because I believe many people they already tried to make their own PCBs at home and when you are making PCB at home then the first step what you do is you do the imaging you put the motive on the top of your PCB then you do the etching you will remove the copper then as the last step you do the drilling and then you may never ever sink that's in a real PCB production this state they may be actually in this an order and this the reason why I included the clip because I think it is interesting in the next video we are going to speak about mask over vias so always when I do replace vias I always cover them with the mask and I ask question that if you need to take some special care about this situation because I've seen some boards I've seen some people making a small hole inside of years so that what is the next video about some people for example they they speak about putting the mask on the vias and they are worried that when this kind of PCB goes into the in process and if the vias are of you know filled with this solar mass it can explode or something to do some do do we need to take special care of the mast we need to put there the hole in the mass for the v8 or you do it here or party damage if you cope let's call that will stay coding your solder mask over all your ear you can do that there will automatically be a four in the video so you automatically coded here it just happened because the mask is not thick enough for region whoa inside of it yeah so when you screech you the math when you're quiet time you're done with the process there will be also like in the mask so just to confirm I always cover the whole via I always called the whole yes I never do any small holes inside of years and we never had any problem in the next video I really had to ask because many people they don't know how boards are assembled if components are from both sides from the top and from the bottom so it is answer some of the back side first because there are smaller components usually logistics but it's not necessary you can assemble any time you want to first and then you don't run it through the oven yet you flip it over and then you come over the other side with the top line and then you go through the other so you don't need only one or they want to oven fly through the pick-and-place computer how do you know that the components are not going to fail off surface tension I really don't know they never they never fall the solder I let you have like some huge you know special inductor humongous and then you glue it out and then you do if I hand up top da da da and the secret was revealed you know everybody knows that if you have components from two sides of PCB they call me go into all on one in the next video we are going to speak about minimum distance between two holes and what can happen if they are too close to each other and we are going to use new words I think I'm pretty sure many people they already know what this means if you if you don't know then plating is the process when copper is put inside the via yeah so when they play the PCB they are putting the copper inside the hole it is the next video does it mean holes too close to each other the holes we need row to hoe yeah I know draw the card what is it first problem how how close is too close 8 mil part is it is any closer and eight non-standard so if we have any sort of drill wander then you can AB sort if everything's okay but you put the Boris or some strenuous testing but something called cat happens where hopper actually grows through the material really I need to somehow mark thee that's interesting we can show you back half later I saw it's too close because I know it's too dangerous to they're too close but that's not the reason reason its plating later when you drill a hole with micro fractures in the material and when you plated the plating solution goes into the micro fractures and if you have two holes that are really close together with micro fractures the copper can win all the way and connect those all together yes this is really interesting even I didn't know I thought you cannot drill holes close to each other because because of Tolerance or because you can break the space between the holes or something like that I wasn't really never thinking about the micro fractures inside a hole Wow in the next video you will see a mentioning which can compare get there fast with real PCB I really like this machine is why I include in the video hello look automatable so we're two very busy edge panel to the Gerber date from upper left the Gerber data and oh I think that anything so if the electrical test says oh there's a connection but we actually etch the traits too far down this machine will catch that the treatment is outside of Tolerance so you only check the most critical places or all the damages it goes why everything Wow it is good it's really good awesome I think it's really awesome that they have the machine which can compare the real PCB with the design region you done yeah with the curve advance this this can give you quite you know the additional confidence that they check all the tracks they check all the weeds and everything in the next video we are going to speak about microvia plating and - hull plating and when I was speaking about plating or a couple of days ago I I said it the process when you put the copper inside the via but during this process you actually put copper everywhere and not only trying to be it's important to know in the first part of the video you will see the laser drilling machine you will see the flashing tender I asked about this V shape of the micro vias it always has to be this v-shaped because the process of placing micro vias is different comparing to the process of waiting the through-hole via when they play with micro vias the solution it needs to flow inside micro via this wire is this region okay so but let's watch the video so you understand the procedure of the plating the micro vias and through home via here it is does the laser always drill through or it can only drill up to certain Laser laser can drill and deck the problem is the plating so if you want to place a laser pole which is only hoping on one side like a blind ear do is to follow a circulation of your cleaning solution so you politely to press for the micro yet and then you plate it again yes and what happened it doesn't flow inside of Julia's for the it doesn't go recover coverage through how we resist you just put the readies inside we you put it there and then you would clean it again or so we put the full with it and then we develop off just my career that I always do only both always oh going to plating thank you still suffer then we remove that it put on another this and expose that true Wow and if you no better way let me know yeah we when you do the yeah so ii thought that when you put math again you're covering microvias only my related yeah okay and then the other stuff gets played it out with a true it really was actually interesting because these what you could see it was only a small part of the discussion you know I asked them questions how how they actually do it because when you just do the plating of the microvias and then in the second step you do the plating of the 200-yard if this plating is not covering each cell or if there are no calls between these plating so it was really interesting here but it's already like forty minute video so let's move to the next clip and it's going to be about coupons and then there is only one more quick very short clip and we are almost done so here is the clip about the coupon so this is very old check the is where we are with the throw and the check the fun yeah I remember this all and we yeah we need to pro and then you played coupons on this case what we have is we have these coupons where we can this that mimics support itself and then with those two funds we can mimic here you know these these are all the coupons that we use the cross section those hold okay so now you can look at if you look at this channel right there is a factor of making circuit boards which is the utilization of material if you look at this panel you could easily fit another four boards here but you can't because we have repeated coupons and we have these cross section coupons all along the sides now with a less expensive board facility they're not going to put all those coupons there and so they'll get an extra four boards here I think those fictional phones it means that is for well the exact way of showing you how much coppers in the hole okay how much because either the holders are cut yet and you've got them in each corner yet because this is a different directions of the material so the grain direction material actually matters so again some people they try to put these coupons on the PCB if you do it yeah do you already have it in libraries in earlier just you know exactly how it should load up or create coupon on the fly based on your design awesome let's import natural so definitely if you don't have to or if engineers don't have to do not play the PCBs into panel to say I would like to have for PCBs two by two and Eckstein on after yeah now this is one right here for impedance if you order a board with control impedance then we put this on the panel and measure and make sure that we're shipping within tolerance if you just kind of control dielectric for you plan for certain thicknesses we don't put this coupon and we don't measure so you're going to get whatever ends up happening we're not accountable for that homes on board so that's the difference in order to so see differences not you can still get what you're looking for people dielectric but you know not getting that certification and that extra test I mentioned these coupons because I remember the times when in some of my projects I play the ball into panel and I created all these coupons around the panel I really remember drawing this impedance coupons and placing there the test point you can see it's not necessary in the PCB company they have their own tools they have their own products they have the software which generates exactly the coupons what they need so you don't have to do it and in the last video we are going to speak about about the factors what influence the price of the PCB the most here it is here it was real this life and the number of lamination they drive along you can hear it a mechanical drill bit side it means the smallest minimum hole on your PCB and number of laminations that how many times your PCB has to go into oven to glue the core and plaything and falls together a simple multi-layer PCBs they go into the oven only once if they only have one lamination but the kind of PCBs what we normally designed they go to three times so it makes the PCB more expensive I really hope you found this video useful I hope you learned something new if you liked this video and you have any questions or there is something whether you still would like to see how they do it in PC production leave the comment okay what is very important like this video because if there is a many likes on the video we can do maybe some other videos inside the theorises company and answer all the other questions which you can help possibly if you would like to see similar video but from assembling process they do the assembly interiors equal to so again if you like this video if they can see that the you know people watching maybe we can record videos also about the passing link so thank you very much for watching I really hope you enjoyed the video and the writer for you next time

Channel: Robert Feranec

Views: 31,508

Keywords: PCB, PCB Manufacturing, Teardrops, Slivers, PCB coupons, Thermal relief, 90 Degree corner

Id: f6_svRNJYls

Length: 46min 10sec (2770 seconds)

Published: Tue Aug 15 2017