OK, let's get started. I'm really excited to have Sam Zeloof here with us today. We've been covering Sam's homebrew ICs for a while now, and it's great to have him for a realtime chat.
Welcome, Sam! Can you maybe kick things off with a little about yourself?
Hello everyone :-)
We're using a laser writer for making the masks
The funny thing: The guy making the masks has also the English name Sam, but he's Chinese :D
Sure! My name is Sam, i'm a second year student in college now and a little over 2 years ago I started acquiring and building the equipment needed to make ICs at home
"Lanzendörfer" sounds like a very traditional Chinese surname ;-)
Last april I succeeded in making a diff amp chip, PMOS, with ~150um gate size and I've been improving things since then to now fab <5um ICs
You think you've got it going on because you can wire up some eBay modules and make some LEDs blink, or because you designed your own PCB, or maybe even because you're an RF wizard. Then you see that someone is fabricating semiconductors at home, and you realize there's always another mountain to climb.
Read this on Hackaday
I'm not Chinese, I just was looking for a job opportunity to build cool hardware ;-)
I'm originally from Switzerland
So how did your first year of college go?
I'm not familiar with your project, but I'm guessing you are working with Si substrate. Where are you sourcing it?
hi sam, biggest question where do you get your photoresist?
Pretty well, lots of work overall but I had some great experiences and was lucky enough to start working on other stuff right away. Outside of classes, I am working in the nanofab there and have started my own lab in that department to develop new fab tools and processes. Not much info on that yet but hopefully soon I can talk more about it, make a website, etc
Yup, Si substrate. you can get small quantities on ebay or here https://www.universitywafer.com/
Sam: Our lambda is 500nm at the moment
January we'll get access to an actual fab with a lambda of 250nm!!
thethoughtemporium ! I saw one of your recent youtube vids and was going to reach out and offer you some photoresist, but couldn't find a contact button on your YT page. In the beginning I used PCB resist from Aliexpress (i think) but if you live in the US most companies will give out samples of their resists. Other than that, make friends in the industry...
The entire PDK and process flow will be published online
am i able to purchase one of your homemade ic's
I'm guessing you are working with already doped wafers?
Yeah, at the moment 4 inch, pdoped, single side polished, prime wafers, but the process is designed
haday, yup. Commonly for NMOS circuits you start with a p-type bulk doped wafer, and the opposite is true for PMOS. For CMOS, you can start with either but commonly p doped are used, then to make P channel devices you implant a N-type well
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