How is it possible?

[autorouter]

But seriously, it is an incredible process to make these things. The easiest bit is to look at the metal interconnections.

Put down a thin insulating layer over the whole chip surface.
Put a thin layer of photographic emulsion (photoresist) over the whole chip.
Print a pattern of holes onto the photoresist.
Develop the pattern, so the exposed photoresist dissolves away, leaving the unexposed photoresist intact. So there are holes in the photoresist where you want them.
Put the whole thing into a plasma etching machine, which etches through the insulation where the holes are. The photoresist protects the rest of the insulating layer.
Wash off the photoresist.

Now you have an insulating layer with a pattern of holes through to the chip below.

Evaporate a layer of metal on top of the insulation. It connects to the chip through the holes in the insulation.

Now use the same photoresist process to print a pattern in the metal layer.

It's a complicated chip, so to get all the metal connections where you want them to go, it needs another layer of insulation, and another layer of metal patterns. And probably a third layer of insulation and metal too.

But once you've designed the chip, and the patterns for each layer, it's basically a printing process, and they can be churned out by the million.

 

[kevenh]

But seriously, it is an incredible process to make these things. The easiest bit is to look at the metal interconnections.

Put down a thin insulating layer over the whole chip surface.
Put a thin layer of photographic emulsion (photoresist) over the whole chip.
Print a pattern of holes onto the photoresist.
Develop the pattern, so there are holes in the photoresist where you want them.
Put the whole thing into a plasma etching machine, which etches through the insulation where the holes are. The photoresist protects the rest of the insulating layer.
Wash off the photoresist.

Now you have an insulating layer with a pattern of holes through to the chip below.

Evaporate a layer of metal on top of the insulation. It connects to the chip through the holes in the insulation.

Now use the same photoresist process to print a pattern in the metal layer.

It's a complicated chip, so to get all the metal connections where you want them to go, it needs another layer of insulation, and another layer of metal patterns. And probably a third layer of insulation and metal too.

But once you've designed the chip, and the patterns for each layer, it's basically a printing process, and they can be churned out by the million.

thanks
And the same info with some expansion from a semiconductor supplier: https://www.vyrian.com/manufacturing-of-semiconductor-chips/

Very interesting and crosses over to how printed circuit boards are made.
I've made PCB - small ones
In my career I've worked on 14 layer PCB
Usually not an issue until R&D need to fix an issue on an inner layer & it means drilling in to the board to break a circuit.

It's sad when a perfect PCB becomes littered with drilling and wires rerouting signals

edit: not my work but a suitable example of a "tweaked" PCB

sorry still not my work but a nasty looking top side signal re-routing: -

 

[stevec]

And in the early days (late 70s) the circuit routing was done by hand at four times the size. We had an an entire department dedicated to it. Nowadays it's all done automatically with autorouters. But they sometimes don't solve all the routes. At least the ones I used couldn't!

 

[autorouter]

In my career I've worked on 14 layer PCB
Usually not an issue until R&D need to fix an issue on an inner layer & it means drilling in to the board to break a circuit.

It's sad when a perfect PCB becomes littered with drilling and wires rerouting signals

When the first samples of a new chip design are made, often some bit of the chip doesn't work as planned. So some poor engineer has to try and tweak the metal layers like this, but working through a microscope, or electron microscope, at the limits of visibility.

 

[Suenliam]

I gave up trying to understand computers when the "main frame" at work was upgraded to a "mini" computer. The main frame occupied a vast room whilst the mini was contained in a tea chest sized box
Sue

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[Deadloss]

If all of this is mind-boggling, try quantum computers!

What is a quantum computer?

Quantum computers are machines that use the properties of quantum physics to store data and perform computations.

www.newscientist.com

 

[Tombola]

I can remember having to load 40 floppy disc for a sage business account program took me 2 day's I had to load in order 1-40 if 1 didn't load correctly I had to start them all again I don't know their capacity

Same..

1.44 mb each lol

 

[Folkranger]

In the early 70's, my Secondary school gave us the chance to buy our first electronic calculator (We were still using slide rules and log tables). They were at a reduced price, but I do remember eating bread and dripping for a couple of weeks after I got one !
I think the most "scientific" thing they did were square roots ? A couple of years later, the prices had dropped and I got a Texas Instruments scientific calculator that took me through tech college.

In the early 70's I used one of these bad boys ay work. Calculators were quite new and they would not let us usse them due to the cost. A cylindrical slide rule now auctions at over £2000.

 

[John Barrett]

My first job on leaving the Army (1974) was Production Foreman for Sontranic Manufacturing in Edgware, Middx, the bulk of our work being for the Post Office: eg. card callmakers, 9A recording units etc. etc.. The girls would take home thousands of Gallium Arsenide photo cells and boards for homework!
We had a flow soldering machine working in a badly ventilated room, so the unfortunate operators were fed loads of milk to stop them getting sore throats from the flux fumes. Wouldn't be allowed today!

 

[kevenh]

Same..

1.44 mb each lol

with the wrong disk inserted doesn’t the installer program write to the screen, for example, “wrong disk! Insert disk 3” or was the Sage’s installer poorly written?
Edit: missed a “

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[mofurt]

Same..

1.44 mb each lol

That was the HD (high density) ones. for 3.5 inch SSDD were 360kB, DSDD 720kB.

Back in the ZX81 days, I think it was Memotech who had a memory system where you could stack expansion packs vetically, and just buy as many as you needed. It obviously paged the memory as you had a 64kB limit on the Z80, and the bottom 8kB was ROM (though unless you properly decoded the address space and toggled the ROM enable line on the expansion port that was mirrored several times).

Anyway, the Memotech unit would allow you to go up to a theoretical 4MB of RAM! That would have cost more than a house, and been rather tall and unstable.

Even now, I remember some of the key address within the memory map.
16396
16510
16514

 

[Stealaway]

It's tiny; the size of my little fingernail and I was staggered to learn that just one GB is about 8 billion bits so my chip has 256 billion bits. Simply mind-blowing. How on earth can there be enough 'connections' to each bit enabling so many to be stored and given an address so that they can be retrieved?

This is my first Atari ST HD memory 'chip' at 30 MB I thought it was amazing.
I cant remember how much it was but suspect it was a bit more than 12 quid

 

[Tombola]

with the wrong disk inserted doesn’t the installer program write to the screen, for example, “wrong disk! Insert disk 3 or was the Sage’s installer poorly written?

Sage is still poorly written

 

[Dorwyn]

The first computers I used had punched paper tapes. These were stored in little drawers and they often became tangled. So we'd go to the top floor of the offices and drop them down the stairwell, then rewind them. Later on in the eighties, in business for myself I had a hugely expensive machine, that used a single floppy disk. This machine was on a monthly service contract. The upgrade to a second floppy drive was ridiculous, so I bought a second floppy drive and wired it in myself. So whenever the engineer was due I had to disconnect it, otherwise they'd refuse to attend if anything went wrong. One day they called unannounced, I wasn't there, my staff weren't aware of my shinanakins, the engineer simply unwired it, and left it on top. Next time he came, he gave me an exaggerated wink. So it stayed in place. I later upgraded it to a 20 meg hard disk. By then I had the courage and knowledge to leave it in place and face the music. Scared of the engineers no longer.

 

[John Barrett]

Talking of 20Mb hard disks, by 1983 I'd made it to Materials Manager for Almex Tcket Equipment in Cirencester, where our NCR 9020 system sported TWO of same. We didn't have a clean room, and my cigar smoking only crashed the discs the once before I wised up...

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[autorouter]

1.44 mb each lol

Luxury. That's the 3.5 inch ones. The 5 1/4 inch floppy disks were 360kB each.

 

[Spriddler]

Goodness me, what interesting replies. Thanks all.
Whilst I said I'm not particularly computer savvy I've always had an insatiable desire to know how stuff works, or at least the general principles.

I'm just back from having a couple of teeth out so while I wait for the frozen mouth to recover I'll indulge in some digital nostalgia...........

In 1961 after completing a 5 year apprenticeship with a R/R, Bentley and Jaguar main dealer I went to Brighton Corporation as a stock auditor where the accounts dep't used fascinating rotary calculators and Sumlock comptometers.

After a couple of years moving up the ladder with manufacturers I joined the military battery firm P.R. Mallory Inc. (later to be renamed Duracell Batteries) as Sales Admin Manager and had the task of introducing a Burroughs L2000 computer which needed only two people; a Punch Card Operator and a Verifier to produce invoice/delivery note sets and produce stock and sales data instead of the 8 lady typists/accountants with typewriters. The company grew exponentially installing an IBM system with large magnetic tape reels on a whole air-conditioned floor above the vast new factory and army of nerdy computer programmer 'Gods' who were never there during the daytime when I needed them as they all seemed to work nights when the user departments weren't open.

I was dead lucky to be in at the start of the digital and semi-conductor revolution of the 70's because my inquisitive mind led me to stay late at night pestering the programmers for knowledge and dreaming up and suggesting new digital applications for our then limited battery range.
No doubt to keep me quiet the firm appointed me as Business Development Manager and I sought out established and embryonic applications for our existing alkaline and mercury cells and developed new ones together with our R&D engineers. I worked closely with Clive Sinclair and his research team at his windmill HQ in Norfolk developing the 'Cambridge' and the 'Executive' calculators. The Cambridge was so cheap that the big retail chains made more profit on the (not included) 9v Duracell MN1604 battery than on the calculator. It may not be true, but I read later that for the first moon landing in '69 the Apollo lunar module had no more digital processing capability than the Cambridge calculator.
Other special projects ranged from powering the location and recovery transmitter for Polaris missiles, the guidance system for Exocet missiles to the first detector of police radar traps to a mad Belgian who had developed a battery powered back scrubber for use in the bath.

Anyway, after various promotions (long story) and vast expansion I ended up touring much of the world as Director of Technical Marketing, (probably because I was the only speaker of foreign languages), but Duracell had successive take-overs by a couple of major American companies (Kraft Foods, Gillette, Procter and Gamble....) who pee'd me off by imposing Ivy League Harvard whizz-kids who were only interested in their own short term careers so I resigned and joined a very small electronics manufacturing company that was pioneering digitised speech and music systems. At that time a 5" x 3" Eurocard with 256 bits cost around £180 and would store 5 seconds of 'Dalek' sounding speech due to the low sample rate and compressed bandwidth necessary to maximise storage capacity. We built a tiny 'recording kiosk' in a corner of the office where I recorded announcements on RAM chips which after customer approval were burned onto EPROMs. The digitised voice announcements varied from lift floor information (you may have heard me at airports and hotels worldwide) to emergency fire instructions to tri-lingual "Please do not leave baggage unattended" to railway station passenger information, to airport, bridges and industrial centres bird scarers (the prototypes of which I mischievously promoted as the 'Flock-off' system), and the cartoon character litter bins at theme parks including Disneyworld asking approaching people in a silly voice to "Please feed me".
You can also blame me for being the first to offer digital 'Music on Hold' systems that included Vivaldi's 'Four Seasons'.

Yep, very exciting times. Anyway, that's enough rambling, and since my numbed mouth's coming back to life I'll risk supping a brew.

 

[ROCHESB]

Way back in the 70s I worked for the Science Research Council; we had an IBM System 360 Mainframe that had 4mb of memory, it was one of IBM's largest systems made at the time, one of only 3 of its type outside the USA.

Each 1mb of memory occupied a frame about 1 foot wide, 6 feet high and 6 feet deep and was on castors. You could see each 'bit' of memory, consisting of a tiny ferrite ring with 3 (I think) copper wires threaded through it.

 

[Van Aert]

My dad working at International Computers Ltd (ICL) Stevenage in the 1950’s

 

[Stealaway]

The chips are often massively bigger than the actual chip just so that can fit on enough connections

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[kevenh]

The chips are often massively bigger than the actual chip just so that can fit on enough connections

You can see what you describe in this EEPROM pic:

 

[Spriddler]

Print a pattern of holes onto the photoresist.
So there are holes in the photoresist where you want them.

Cuh, there's little that's really new. Ever since the 1830's the fairground organ tunes were programmed with holes in cards.

 

[Coolcats]

In the early 70's I used one of these bad boys ay work. Calculators were quite new and they would not let us usse them due to the cost. A cylindrical slide rule now auctions at over £2000.View attachment 698504

What an object of beauty I have a slide rule but recall a chemistry teacher had one similar to your photo. Whilst Space X is heralded as a inventor of new space rockets, what is missed is that much of what they do the calculations were hand crafted back in the day buy engineers and scientists using slide rules and good old fashioned pen and paper. Even the self landing boosters as marvellous as they are are iterations of previous engineering feats. although I cant find it there were competitions for self landing boosters I suspect Musk brought in to some of those engineering feats or hired the engineers behind it

Slide Rule well they just Rule

 

[Coolcats]

You can see what you describe in this EEPROM pic:

Dont leave it in the sun light

 

[Spriddler]

The 0 and 1 memory 'bits' are represented by billions of black and white smoke particles,....... If for some reason it is over-stressed, the seal breaks and the smoke is released, it's impossible to get the smoke back into the chip, and it's why the smoke looks grey when it escapes

Luckily, I can still get original replacements for my car and motorcycle wiring looms.

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[Spriddler]

"I think there is a world market for maybe five computers."

Thomas Watson, president of IBM, 1943

 

[68c]

Dont leave it in the sun light

No, the magic will evaporate, along with the programming.

 

[autorouter]

If all of this is mind-boggling, try quantum computers!

A key principle of Quantum Mechanics is that you can understand it and not understand it at the same time

 

[Deadloss]

A key principle of Quantum Mechanics is that you can understand it and not understand it at the same time

I’m afraid I’m firmly in the classical world of just not understanding it - despite having read a number of Brian Cox (the physics one) books

 

[NigelNovice]

When I got my first PC after tinkering with a Speccy 48K, it was a P2 144 processor with a heady 64k of ram and a 6gb hdd running Windows 95, I soon realised I needed a bit more ram and so saved up and trotted off to local computer shop with £74 (as my mate had just bought some and we had similar set up) in my sweaty little (about 36 yo) palms and came out with change it was only £68 as price had dropped as things were and windows habit of crashing requiring re-installation + drivers, when my mate showed me Nortons ghost (via his techy brother) a copy was acquired, saved many a late night of re-instals, as things were in them days and erm unofficial copies of windows (and office suite) were easier to get hold of than a bag of weed I soon upgraded to win 98 and then ME and then to XP missing out Vista as it were crap then on to my first legit copy Win7 and then a free upgrade to Win10 with several hardware upgrades along the way, always built me own after the first one, currently an 8 core processor, about 6 terrabyte of multiple hdd and 32Gb of ram + 8Gb on board graphics card ram.
One of my tasks when teaching apprentices (retired) at one point was to teach a bit about IT, mainly using the MS office suite but also showing them the hardware and how it worked, I had a box of floppy discs and tried to explain the hole in the disc that stored 1.44mb was about the same size as the micro SD card that was in their phone and at that time the max was about 30gb, I also had an old spinner hdd that I took out of a PC my brother had given my mum, it was his old works PC, I tried to upgrade it to win98 and it said nah, it was a 340mb hdd and wasn't big enough to cope, I has always amazed me that hdd's remained the same physical size but capacity increased, but now we have solid state hdd that are smaller still.
Currently contemplating on a new build as Win 11 wont fit on this machine - is it worth it nowadays?

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