RepRap Silicon!

Hi, I have a vision of a printer into which we must insert a circular silicon disk (thats used in fab) and you have a software your computer where you can write VHDL code (It will be great if we can use GNU electric (http://www.gnu.org/software/electric/) to interact directly with RepRap Silicon ).

Once the circuit is verified and a make button is pressed you will get the circuit out fabricated!

Future versions of RepRap may have the feature of attaching leads and packaging the IC. With this we can create true free hardware community.

Regards
A.K.Karthikeyan

A nice idea. What do you know about doping?
I have daydreamed of a similar system since around age 15, so I, for one, am rooting for it.

Well my school has a semiconductor fab, it takes up a garage sized room. It would be awesome to have something that does the same and fits on a table top.

Did I mention the hydrofluoric acid(eats away glass) bath used to etch the chips and that its not automated? It also uses normal visible light halogen lights to expose the chips(old hand-me-down apparatus from local semi-industries).

The hardest part of a microchip for an amateur to make would be the vacuum coating and plasma etching apparatuses. The photo-masks also present a problem.

Everything else is fairly simple.
The clean environment should be easy given the availability of HEPA filters. The centrifugal coating machines should be easy to manage. The exposing machines should be easy, just a halogen light or an eprom eraser.

I've long thought a souped up LCD monitor could be used as a photomask, maybe with a prism arrangement so the same section could stand in for every area of the wafer. Alternately, there's x-ray lithography. And, no, I don't know how big that'd make it.

Heres an alternative:
[www.polyic.com]
If you do a google search on "inkjet printed polymer integrated circuit"you'll see lots of folks doing very similar work with a modified inkjet printer. This looks like it could be a game changing technology if it comes down to a tabletop level.


Brian D

Edited 1 time(s). Last edit at 03/12/2008 09:07AM by BDolge.

FPGA's are getting cheaper. They could become as ubiquitous as microcontrollers, and could provide for most of chip needs. And if you don't need the device anymore, you can reprogram the FPGA to do something else. Maybe not as satisfying as etching your own silicon, but probably cheaper and more practical in the near future.

I am still confused about the difference between FPGA and EEPROM.

An FPGA is an array of configurable logic gates with configurable routing to connect them pretty much in any way you want. You can form registers, adders, etc, even complete CPUs if you want and the device is big enough. You can implement algorithms in hardware that run very quickly.

On the other hand EEPROM is just memory that stores bits.

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[www.hydraraptor.blogspot.com]

FPGA'a are programmable logic devices.
EEPROM are Electrically Eraseable Programmable Read Only Memory, ie memory devices.

I play around with Xilinx Spartan 3's myself and have built complete systems on a chip running linux. Albeit connecting with a serial port.
The plus side of FPGA's is the flexibility. You can do microprocessors, video display interfacing, memory, serial interface(with proper buffering for voltage), USB, etc
The downside of FPGA's is that flexibility can make them more challenging to program and run stable.

A good source for fpga boards is www.digilentinc.com. A 1M gate array is more than enough to house a 32 bit CPU and additional logic to interface to other devices.

I understand the acronyms. My confusion is how PROM was explained to me. I'm starting to see a difference, but to me a PROM, E, EE, or whatever, holds a truth table and nothing more.

Would it be safe to say a FPGA is an EEPROM with memory?

A PROM is a programmable read only memory. Although you could use it to store a truth table they are normally used to store programs for micro processors. E.g. your BIOS on your PC will be in a PROM. They are much slower than logic gates and FPGAs.

An FPGA is a sea of gates with programmable routing. It may have some EEPROM to hold the its configuration, but more often a RAM.

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[www.hydraraptor.blogspot.com]

Hey, why not just do what the MIT fab lab people do and just use cheap off the shelf atmel microcontrollers?

Speaking of FPGAs, I heard about some super-FPGAs awhile back that could reconfigure in milliseconds or less.