Near Field Communications

[Nick]

Guessed it would only need to store an ID. This is programmed at time of purchase but where is that stored? Is the device or chip so tiny that I cant feel it or find it?

The GUID is programmed when the chip is etched at the factory - its not retrofitted. As an example, the GUID for TI MSP430CPUs is generated with a TI-unique root number, followed by an monotonically increasing wafer serial number, followed by the X & Y coordinates of where each die is on that wafer. Thus, when a chip has problems, you can use the knowledge of how its GUID is made up to identify the exact wafer it came from and the precise location on that wafer. Cool, or what

If you have an Oyster card (which uses the NXP chips) you will not feel anything - the silicon wafer is sawn into FFC (Film Frame Carrier) format, basically an array of bare dies, 120um (about 4.5 thou) thick - non-working die are marked with a red dot.

These bare die are then embedded in the plastic of the card (which acts as their packaging) - you can play with this using an old bank card and a scalpel to dig the die out - any connections are bonded directly to the die - in this case, there are only two.

There is another format for the less adventurous, known as PLLMC/MOA4 (Plastic Lead-Less Module Carrier), which is a very tiny minimal package, about 4mm x 5mm x 0.3mm thick and which is used for binding to standard PCBs - Farnell sell these.

Basically, they are so small they're hard to see! Your one will (probably) be where the two leads from the printed antennae seem to meet at the left hand end of the photo of the obverse of your card.

[Radio Fixer]

So you buy the Pass and a reader logs the factory etched ID *, into the chip, (its obvious when you know, that that is the way to do it), in a file, and attaches to it how many days you have bought and what areas etc. Every time you use the Pass it checks for validity and "Beep" away you go.

* How do they do that? It must be programmed in some way as they wouldn't change the masking ...

How many digits is the ID? Is there so many there is no need for a particular card ID number to get used again for decades ?

I expect to you Nick its not magic but when you packed in when TTL and Cmos packages were the thing it is to me.

And thanks for so much enlightenment

Gary

[Nick]

The MSP430 id is 8 bytes, but a typical UUID is 128bits long - essentially they'll never repeat.

The die-specific data is programmed into ROM by laser after the die is complete and tested.

To give some idea of how sophisticated these machines are now, a friend who is one of the world's few lens designers for FAB plants explained it thus:

ICs are produced by depositing layers of material onto a silicon substrate, coating it with photo-resist, exposing the resist in a thing like a glorified slide projector, then developing it and etching away the original material (or implanting the whole thing in an ion implanter to dope the exposed area of silicon). Anyone who's had a go at making their own PCBs will understand the principal. It's the detail that's astonishing. First of all, as mentioned above, the smallest feature printed on the silicon can be as little as 40nm across. Lets get that in perspective. A human hair (the universal indicator of smallness in the same way that football pitches and double-decker buses are the universal bigness indicators) is about 80 microns in diameter, so one micron is one 80th of a hair. 40nm is four hundredths of one micron, so about 1/2000th of a hair. Features that small have to be printed with perfect definition across a field up to 30mm square. Since the silicon substrate (or wafer, as they're known) we're talking about is up to 300mm in diameter, a grid of exposures is made, with the wafer being moved on a stage under the lens from step to step (hence stepper) until the whole wafer is covered.

That's the easy bit.

Chips are made up from up to thirty layers of material, each one with its own pattern, which of course has to be aligned to the one below to an accuracy of about .01 microns. Think about that. The wafer is 12" in diameter, and is sitting on a stage made of quartz about 15mm thick. That in turn sits on piezo feet that keep the image in focus (depth of field is around 1 micron). This whole assembly weighs about thirty kilos, and has to be aligned under the lens, focussed, exposed, then moved to the next image, aligned again to .01 micron, focussed and exposed in a cycle that takes around one second. To achieve this, the stage sits on an air cushion on top of a lump of granite that weighs around half a ton, and is driven in x and y by a couple of hefty great linear motors, position being measured by laser interferometers. This one-second cycle covers a wafer in about thirty five shots, so a wafer goes through in about 45 seconds, hour after hour, day after day. Astonishing.

The current production lenses use 193nm deep UV . They consist of a lens about 1.5m long made up of 30-35 elements made from Calcium Fluoride and Fused Silica , up to 220mm diameter. Essentially it's like a giant microscope objective working in reverse, taking mask designs at 5x final scale and reducing them onto an active chip area of about 30x30mm.

Originally , lenses at 193nm were operating at NA of 0.5 ( = F/1 ) in air, and diffraction-limited. That gave about 90-100nm linewidth, I think. Since then, they have pushed the designs to an NA of over 0.9 in air, then with water immersion between the lens and wafer, to an effective NA of 1.3 - which is how the 40-50nm linewidths have been achieved.

The lens element surfaces have to be finished to an regularity of about 1/100th of a wave of light or better, in the visible. This requires conventional polishing followed by cycles of measurement and ion-beam-figuring ( I believe ) to finish.

The lens elements are mounted into Invar ( ~zero expansion) cells and assembled as a stack, one lens at a time, using optical monitoring of the lens to get it centred. The Invar cells are diamond-machined to about 0.5 micron parallelism.

These lenses produce by far the most 'information' in one shot, of any optical systems made in any field. If you wanted to capture the available detail from this lens using a digital sensor, you would need to use about 430 Giga-pixels - I know as I calculated this recently for interest, after seeing an impressive 2G-pix image assembled from shots above Everest base camp.

Alternatively, consider that if the chip was enlarged to 400x400m , the line structures would be at the 0.5mm level .

Very few people understand the extraordinary technology that goes into the common processor chips that are in their computers

[Radio Fixer]

Yes! truly magic and taken for granted by virtually every user who has no conception of what is involved. Then moans if the PC does something it shouldn't !

Good write up and I will store that.

thanks Gary

[Radio Fixer]

Just to put a little history to the thread here are some scans of a data sheet I still have from 1969. It is RTL (Resistor, Transistor logic) and the few devices available came in shirt button sized cans with radial lead out. It gave industrial engineering a task of making up a forming jig so that they could be hand mounted in PCBs and not fall out.

It seems so quaint now that you got a schematic that you could understand, well the JK flip flop was a bit tricky. But much of the first PCM (Pulse Code Modulation) and digitisation of the telephone network was done by STC using them. All long ago now.

   
   
   
   
   

I wonder what the size of the chip geometry was back then?

Gary

[Refugee]

They are the ones that came before the 74XX series.
I still have a home made transistor tester with a 741 op amp in a TO5 that drives the indicator.

[AlanBeckett]

They are the ones that came before the 74XX series.

930 Series DTL came in between I think.

Alan

[pwdrive]

There's some info on some of the early stuff in the page shown in the link below, I have not explored it all:

http://www.vintchip.com/flatpack.html

Lawrence

[AlanBeckett]

Actually the first part of that Link is wrong. Integrated Circuits were invented and made at Plessey Caswell before the Americans.
As is not unusual we failed to exploit the advantage

Alan

[pwdrive]

A 1960's film about making IC's....By Fairchild, there's a promo add not long after the start of the film making various claims like companies do. This film is the first one that caught my attention in a Google search, there might be be others that are better.

http://www.youtube.com/watch?v=z47Gv2cdFtA

Lawrence.