Very high interconnect density

We are all faced with increasing interconnect density in all we do. This means smaller everything, especially components and that which they are mounted upon but, hopefully, without smaller minds and thoughts. It all demands more process control and evidence of quality effected by it. Therefore, I am again off to seek better ways, and forums, to ensure quality through more effective process control so we don't react to defect without it.

Go get 'em folks.

Earl Moon (MoonMan)

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| We are all faced with increasing interconnect density in all we do. This means smaller everything, especially components and that which they are mounted upon but, hopefully, without smaller minds and thoughts. It all demands more process control and evidence of quality effected by it. Therefore, I am again off to seek better ways, and forums, to ensure quality through more effective process control so we don't react to defect without it. | | Go get 'em folks. | | Earl Moon (MoonMan) | MoonMan

Yeah! Things advance. The first PCBs I had to deal with (in 1954) were on SRBP with, believe it or not, rolled copper foil (electrodeposited copper foil was an invention of the Royal Mint in England c. 1955 and was initially made on polished stainless sheets as a batch process). The line widths and spacings were c. 3 mm and the copper came off even if it saw molten solder 1 m away. Do you know how we made them? They were printed in a plate offset machine with a sticky ink on which we hand sprinkled an asphalt powder (dragon's blood) which we fused in an oven. Etching was initially done in nitric acid, quickly replaced by ferric chloride after a guy was poisoned by NO2 fumes. For prototypes, our photoresist was fish glue sensitised with potassium bichromate: exposed to the sun for three hours, developed with hot water. Those were the days (God forbid!)!

Now we have HDIS with 25-50 �m vias and I have even seen an experimental circuit with 15 �m track widths and spacings, 2.5 orders of magnitude finer than our original ones. It has been a very hard job to keep up with progress in our industry and, after only one year's semi-retirement, I'm beginning to feel it all slipping past me. The rate of change is alarming.

But don't abandon us here, Earl, in your seeking new pastures of green information. Your advice and wit will always be appreciated.

Best regards

Brian

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| We are all faced with increasing interconnect density in all we do. This means smaller everything, especially components and that which they are mounted upon but, hopefully, without smaller minds and thoughts. It all demands more process control and evidence of quality effected by it. Therefore, I am again off to seek better ways, and forums, to ensure quality through more effective process control so we don't react to defect without it. | | Go get 'em folks. | | Earl Moon (MoonMan) | Yeah, the challenges of the future, but what still bites are the challenges of today. Most of the topics handled here seem very well known to some folks but still a mystery to others. Process control without understanding the process is difficult to obtain you have to rely on that machinery you paid a lot for and so far works until you try to have it do things that it�s not capable of. The effectivness of process control is highly dependend on understanding all details, parameters and impacts on the result. For example The IR versus Hot Air issue, if there�s a real good understanding of the rework process you might use either one and get the right thing out of it. So the understanding of processes and the way equipment does its job is essentiell and the basis for implementing new technologies. New challenges like interconnect density may be checked first if known processes still apply or if new methods have to be developed. IMO it�s more the part of the Big Dogs to get it solved for they have the need, time and money first. The problem is more how to spread this knowledge so that the whole community can benefit from it. Training is one thing but as seen more and more there�s less focus on that in many especially smaller companies and the folks there seem somekind of swamped by the demands of modern technology. So any kind of forum can�t help getting this deficiency eliminated, it�s just a drop on a hot stone or an elusive treatment of symptoms that keeps us going going going... Offering training courses and the will to join them are substantial things in developing a company to a more competitive one for today and for the future.

So, in the meantime get this thing here alive until there will be only jokes to argue about.

Hope it�s on topic Wolfgang

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| | We are all faced with increasing interconnect density in all we do. This means smaller everything, especially components and that which they are mounted upon but, hopefully, without smaller minds and thoughts. It all demands more process control and evidence of quality effected by it. Therefore, I am again off to seek better ways, and forums, to ensure quality through more effective process control so we don't react to defect without it. | | | | Go get 'em folks. | | | | Earl Moon (MoonMan) | | | MoonMan | | Yeah! Things advance. The first PCBs I had to deal with (in 1954) were on SRBP with, believe it or not, rolled copper foil (electrodeposited copper foil was an invention of the Royal Mint in England c. 1955 and was initially made on polished stainless sheets as a batch process). The line widths and spacings were c. 3 mm and the copper came off even if it saw molten solder 1 m away. Do you know how we made them? They were printed in a plate offset machine with a sticky ink on which we hand sprinkled an asphalt powder (dragon's blood) which we fused in an oven. Etching was initially done in nitric acid, quickly replaced by ferric chloride after a guy was poisoned by NO2 fumes. For prototypes, our photoresist was fish glue sensitised with potassium bichromate: exposed to the sun for three hours, developed with hot water. Those were the days (God forbid!)! | | Now we have HDIS with 25-50 �m vias and I have even seen an experimental circuit with 15 �m track widths and spacings, 2.5 orders of magnitude finer than our original ones. It has been a very hard job to keep up with progress in our industry and, after only one year's semi-retirement, I'm beginning to feel it all slipping past me. The rate of change is alarming. | | But don't abandon us here, Earl, in your seeking new pastures of green information. Your advice and wit will always be appreciated. | | Best regards | | Brian | As no longer a participating or subscribed SMTnet member, I now can only be reached at pod@ix.netcom.com

Thanks all,

MoonMan

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| | | We are all faced with increasing interconnect density in all we do. This means smaller everything, especially components and that which they are mounted upon but, hopefully, without smaller minds and thoughts. It all demands more process control and evidence of quality effected by it. Therefore, I am again off to seek better ways, and forums, to ensure quality through more effective process control so we don't react to defect without it. | | | | | | Go get 'em folks. | | | | | | Earl Moon (MoonMan) | | | | | MoonMan | | | | Yeah! Things advance. The first PCBs I had to deal with (in 1954) were on SRBP with, believe it or not, rolled copper foil (electrodeposited copper foil was an invention of the Royal Mint in England c. 1955 and was initially made on polished stainless sheets as a batch process). The line widths and spacings were c. 3 mm and the copper came off even if it saw molten solder 1 m away. Do you know how we made them? They were printed in a plate offset machine with a sticky ink on which we hand sprinkled an asphalt powder (dragon's blood) which we fused in an oven. Etching was initially done in nitric acid, quickly replaced by ferric chloride after a guy was poisoned by NO2 fumes. For prototypes, our photoresist was fish glue sensitised with potassium bichromate: exposed to the sun for three hours, developed with hot water. Those were the days (God forbid!)! | | | | Now we have HDIS with 25-50 �m vias and I have even seen an experimental circuit with 15 �m track widths and spacings, 2.5 orders of magnitude finer than our original ones. It has been a very hard job to keep up with progress in our industry and, after only one year's semi-retirement, I'm beginning to feel it all slipping past me. The rate of change is alarming. | | | | But don't abandon us here, Earl, in your seeking new pastures of green information. Your advice and wit will always be appreciated. | | | | Best regards | | | | Brian | | | As no longer a participating or subscribed SMTnet member, I now can only be reached at pod@ix.netcom.com | | Thanks all, | | MoonMan | Bye Earl. Good luck and thanks for your generosity. Ta. Dave F

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