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New technology doesn’t exist; everything was invented in the 60’s

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PartialDischarge:
I agree that the 60s saw a huge innovation that most people ignore. I posted something along that line last year:

TimNJ:

--- Quote from: T3sl4co1l on May 30, 2021, 11:48:29 pm ---Y'know, now I wonder what exactly drives wire bonding.  So, we have CSPs now of course, and that's probably just because it took a long time for PCB-level density to get high enough to demand it.  At the same time, you're paying a premium for the fine pitch PCBs (probably HDI as well) to use them.  So it's not used in much quantity, except when there's no choice (i.e., cellphones yes, washing machines no).

Which have in turn been available in many forms over the decades, whether as laminated interposers (who makes those anyway? they're basically PCBs, but not...), or fired ceramic-metal bodies (classic IBM).  Obviously the latter isn't exactly affordable, but the former is essentially any old PCB, if not a full sized one.  Were they just not able to hold tolerances over whole-PCB distances, or something with multiple layers (getting copper, soldermask, vias, etc. to line up) or what?

And why not interposers all the time, or at all?  Lead frames must suffer some tolerance issues, perhaps?  Otherwise, why not flip-chip directly to them?  (They sort of do this with some power transistors, with wide top-side connections rather than bondwires.)  Or if interposers are superior, then why not use them instead of lead frames?  Well, obviously lead frames must be cheaper, at least for that middle space where the number of leads, and density, isn't too crazy, and who cares about flipping.

On the other hand, clearly wirebonding isn't a painful process; it's done fast and automated, and adapts the fine pitch of the chip to the coarser pitch (and looser tolerances) of the lead frame.  The question of course is, how much can an alternative save, if any?  Evidently, not much in the average case, but I just wonder what the quantitative breakdown is.

Tim

--- End quote ---

That's an interesting thought and I don't really have an answer, but here are a few quotes on that subject:


--- Quote from: Doyle, 1966, page 179 ---
The flip-chip method has not been used to any appreciable extent, since the bonds cannot be seen, and it is difficult to assure that they have been made, or that individual bonds are strong. To overcome this difficulty, a reverse process has been used in which the conductors are placed on to of the chips so that individuals bonds can be inspected. This is accomplished by bonding etched-foil patterns to the terminals on the chip, or by fastening the chip face up to substrate and depositing the interconnection film simultaneously on both the chip and substrate.

In another face-bonding method, the chip is raised slightly above the substrate with a thick bonding pad of some sort. This gives more leeway in aligning the planes of the chip and the substrate. Three pads on the chip are sufficient to define the plane. Mating is easier if the material is soft, like solder. Raising the chip makes it possible to inspect the bonds visually.


--- End quote ---

As you seem to suggest, there might have been some concern with the levelness of the bonding plane. Maybe even small imperfection in the lead-frame could lead to to a bad face-bond. On the other hand, this is basically compensated for with bond-wires. But, the author does suggest some remedies to make up for these imperfections.

Some other notes:


--- Quote from: Doyle, 1966, page 182 ---
Face bonding is not a panacea. Packaging engineers point out that die-bonding cools the chip better. The thermal contact between the silicon mass of the chip and the substrate is far larger than the thermal contact provided by the face-bonding pads. Die bonding will still be preferred for devices that must dissipate large amounts of power until simple, effective methods of heat-sinking, face-bonded chips are developed.

--- End quote ---

I thought that was interesting because I figured thermal resistance of a face-bonded chip "direct" to substrate would have a lower thermal resistance than bond wires, but for some reason that's not the case? Difference in material used for the bond? I'm not sure.

As you mentioned, these days we have some fun, bond-wire-less packages that have the aforementioned heatsinking qualities. For example, Nexperia's LFPAK.

TimNJ:

--- Quote from: Rick Law on May 31, 2021, 06:39:23 pm ---
--- Quote from: TimNJ on May 30, 2021, 07:11:15 pm ---...
But, was perusing a local vintage electronics store (Green Brook Electronics) and picked up a copy of “Thin-Film and Semiconductor Integrated Circuitry” (John M. Doyle, 1966).

--- End quote ---

I assume you mean the Green Brook Electronics on West-Bound Rt22 near Union?  Do they still sell electronic parts and things?

There was a Green Brook Electronics on East-Bound Rt22.  That used to be my go-to place when I needed parts urgently.  I was sadden seeing it disappeared.

Recently I drove farther East on Rt22 and noticed a store by the same name West-bound Rt22.  But due to virus shut-downs, I did not stop there.  My solder-sucker is on the fritz, I was planning on giving it a try to see if it was the same store...

--- End quote ---

As the other's have noted, there is a new store. Quite a variety of stuff in there. Lot's of stuff in the back: oscilloscopes, microscopes, and lots of obscure equipment that I can't imagine anyone really needs these days, but it's there. I like the book section, although it's 0% organized, and there's a somewhat alarming amount of weird conspiracy theory/anti-communism books interspersed in there.

TimNJ:

--- Quote from: daqq on May 30, 2021, 07:34:08 pm ---
--- Quote ---Indeed. In general, the delay in adoption of new technologies (including mathematics, algorithms, etc.) is probably explained by there being no real need or no practical (see: economical) way to implement, at the time of discovery.
--- End quote ---
That's the thing about basic research - the profits may be a long way down the line - they might even not be, but if they are they can be massive. Just look at scientific novelties and curiosities of their time like electricity and radio waves.

--- End quote ---


--- Quote from: coppercone2 on May 31, 2021, 05:26:55 am ---try finding a good explanation of quantum circuit thats not a business talk loaded sales pitch (cough ibm)

new technology = we want to help you with everything, for a fee, the only thing you need to know is if it brings value to your company

I want to learn about quantum circuits and I am getting altium style ecosystems being pitched to me. lets skip over the boring obvious details (not obvious or boring, more like danger of competition). most likely its kept at 1% growth for trade secrets to be kept or something silly like that

--- End quote ---

I guess the question is...what fundamentally changed? For one, I know federal grant money (at least here in the US) for basic scientific research is way down. Plus, we don't have too many crazy federally-funded endeavors like the space race. These days, I think the public would just not allow it, and probably rightfully so, considering the many other problems we have. Although, federal money to basic science research institutions still sounds like a better idea than giving Jeff Bezos a zillion dollars to do god knows what. But I digress.

Any other shifts in thought?

dietert1:
Internet in the 1960s? Any DSO in the 1960s? How about metal film resistors, TFT displays, white LED lighting, terabyte hard disks (quantum hall effect, 1980), GPS, Lithium ion battery, gold ultracaps, GaN HEMT, vaccines within a year, mutations every month.. We are living in very interesting times!

Regards, Dieter

Concerning semiconductors: For me modern FPGAs are the most surprising development. We can nowadays implement hundreds of DSPs on one chip and run them at tremendous clock rates. Another one is the availability of video processing AI systems in a credit card size form factor (JETSON).

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