Newbie question: Beyond SMT - Page 1
Forum section: electronics / general

author: Tharkun
author_rank: Newbie
timestamp: July 09, 2021, 10:07:47 am
content: What technology might replace SMT?Would it be possible in the near future to make chips the same way PCBs are made now, highly customisable and in very small batches, and at similar prices?Could there be some way of “printing” electronics onto suitable materials? Might SMT advance to this kind of thing?Sorry I’m somewhat new to electronics so maybe I have done an injustice to the facts. Just interested to know where things might go.

author: Bradlez
author_rank: Contributor
timestamp: July 09, 2021, 02:18:20 pm
content: I guess it depends what you mean. In a way, ICs are replacing SMD passive components by integrating more components in them. In the old days, it was hard to include capacitors inside IC designs. Now, putting capacitors inside IC designs is way more trivial. Comparing LM386 against modern op-amps is just one example.I think something similar can be said about those cheap mass produced electronics that put everything under an epoxy blob (chip-on-board) in a die.

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: July 11, 2021, 11:31:14 pm
content: I think photonics will be the next step, as in replacing as much of the humble electron for the photon as possibleBack when I was at uni there were a number of groups researching how to make the photon equivalent of resistors/capacitors/inductors, from memory it was the inductor that was tricky

author: Whales
author_rank: Super Contributor
timestamp: July 12, 2021, 12:22:37 am
content: Printing resistors: already done. I've seen PCBs with printed carbon traces between pads. I have some conductive acrylic paint on my shelf that I've been playing with too.Printing capacitors: I've made somealuminium electrolytic capacitors directly on flat surfaces using pastes, but they're wet and dry out (no simple method of sealing)The real crown jewels will be printed transistor junctions (or anything transistor-like that can provide gain). Once people achieve that: "printing" a circuit might actually become interesting.Amusing possibly-printable lights (LED-equivalents):I've made somebut again not very practical, dry out and need high AC voltages.

author: tszaboo
author_rank: Super Contributor
timestamp: July 12, 2021, 10:39:49 am
content: PCB embedded components.They place parts inside the PCB. Multilayer PCB where there are cavities for parts, they pick and place them, reflow or wire bond, and then laminate the PCB, and it might go though a second reflow process. Its sort of 2.5Dhttps://www.we-online.com/web/en/leiterplatten/produkte_/ect/ect_uebersicht.php

author: SMTech
author_rank: Frequent Contributor
timestamp: July 12, 2021, 11:52:59 am
content: I think engineers will always want building blocks so they will always want and need components and so we will always have SMT, some things are way beyond anything we can even conceive simply "printing" for decades. One thing people are working on is solder paste that doesn't need to reflow, instead its printed on in its liquidous "melted" state, possibly by the placement machine itself and then makes a joint as soon as the component is placed in it. It sounds like voodoo but that is what I understood they were aiming for.

author: David Hess
author_rank: Super Contributor
timestamp: July 12, 2021, 01:55:40 pm
content: Quote from: Tharkun on July 09, 2021, 10:07:47 amHybrids using thick film screen printing and thin film evaporation have been around for decades. This includes chip and wire and flip-chip attachment of semiconductors.Some old ICs, and some modern ones, are actually hybrids inside of their packaging.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 12, 2021, 04:54:14 pm
content: Uh... how about like, analog switches and stuff?For which, FPGAs have been mainstream for a long time now, but analog SoCs never really took off. There are still a few neat ones out there, but nothing commanding huge market share.The major board-level problems are board-level anyway. ESD/surge, filtering, etc., come in too many combinations of voltage range, peak rating, bandwidth, leakage, number of channels, etc. to integrate on chip in any meaningful way. You can't simply configure these, like you can configure the logic within an FPGA. It has to be hard wired.Or I suppose it could be MEMS switched; but MEMS switches also kind of suck, they have a lot of difficulties as I understand it.There are some common examples where this works. Interfaces like RS-232, 485, CAN, etc. often have 8/15kV ESD ratings. There's basically two correct options: leave it open to the designer, or standard commercial rating.Or, I mean, there's the default -- basically all ICs have at least 1-2kV HBM rating, usually done with clamp diodes and a common clamp, or a snapback diode per pin.I don't know how reliable this assumption is.. I've seen at least one SoC that contained no ESD spec, in any of the relevant datasheets/appnotes I could find; I had to ask the reps, who asked the IC designers, who said it complies with some IC specification I don't own. Why they didn't simply put that in the datasheet, or how no one else ever asked before, I have no idea...Tim

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 13, 2021, 12:08:24 pm
content: Quote from: David Hess on July 12, 2021, 01:55:40 pmWhen I was a kid and took apart my 1541 disk drive, I saw the large hybrid in there with all these little bumps under a black coating. I was suitably impressed.IIRC it was the head r/w circuitry in there.