How to design Hybrid PCB ? - Page 1
Forum section: electronics / beginners

author: Icarus
author_rank: Regular Contributor
timestamp: July 24, 2015, 11:36:41 am
content: Hi Folks;I've never designed a hybrid circuit.I'm wondering how to make one ? Could you put some IC's on it ? or Do you have to design every single thing ? Like a regular IC ?

author: XOIIO
author_rank: Super Contributor
timestamp: July 24, 2015, 12:20:01 pm
content: I doubt the design process is much different than regular PCB's, getting it manufactured would be the tricky and expensive part.

author: ovnr
author_rank: Frequent Contributor
timestamp: July 24, 2015, 12:22:44 pm
content: Hybrid, as in ceramic substrate?You can put whatever you want on it. One of the bonus points (beyond electrical performance) is the screenprinted/deposited resistors.Note that 2-sided ceramics is more expensive; many circuits have multiple layers of screenprinted metal.Also, protip: Include why you're asking. Do you need to make some? Are you just wondering? If you do need some made, what for? Why ceramics and not PCBs?

author: SeanB
author_rank: Super Contributor
timestamp: July 24, 2015, 07:47:52 pm
content: Just make a regular small PCB and use pins on the edges to mount to the main board. Hybrid will involve designing the circuit, then scaling it ( as the ceramic shrinks during firing) to size, making a set of silkscreen masks for the conductive ink layers, the ceramic isolation layers where they cross over each other, the resistive ink making resistors and then a final screen for identification writing. Then you start with an unfired "green" ceramic sheer, deposit your layers of inks and masks, with a dry cycle between each layer, followed by an inert gas firing to both fuse the substrate into a ceramic, fuse the conductive inks into tracks and fix the resistors. Then you take the finished blank and test it, trim the resistors using either laser or sandblasting, then mount the other components after a solder paste application, reflow then as a final process wire bond the chips or transistors in. Final part is enclose in a hermetic case.Small board with SMD parts and SM chips is around 1% of the cost, the hybrid only comes into play if you need a high temperature operation unit, or protection from a hostile environment where potting a board will not be enough.

author: Icarus
author_rank: Regular Contributor
timestamp: July 25, 2015, 06:27:04 pm
content: I see. It seems too much expensive for a home-project. Thank you every one;

author: codeboy2k
author_rank: Super Contributor
timestamp: July 25, 2015, 08:24:43 pm
content: Quote from: ovnr on July 24, 2015, 12:22:44 pmExcept for the resistors, I've wondered in the past if anyone has ever tried screenprinting ceramic at home (like a top layer PCB, no vias). I did ink based screenprinting as a kid, and it wasn't hard. It would seem that one might be able to easily screen print silver traces (or something else?) instead of buying copper clad fr4 and etching.Has anyone ever tried it at home?

author: SeanB
author_rank: Super Contributor
timestamp: July 26, 2015, 09:15:17 am
content: Screen printable silver inks are available, but because of the binders required they are both high resistance and tend to corrode if not protected with a sealing coat.There are a lot of carbon loaded screen print inks though, used to do things like remote controls, where you want a carbon coating on the switch pads for lifetime, and where the carbon is used to make the top side signal wiring. The silk screened ink is put on the drilled board so it goes through the via holes to make contact, then it is placed in a controlled atmosphere over to both cure it and drive off the binders, leaving a thin carbon film behind. After that a second screen placed a toner in binder like plastic screen printable paste coat on top, that then is cured and heated in the CA oven to melt it into a protective film over the carbon, filling in the vias at the same time so they do not go high resistance ( or at least not for a year or five).You might be able to do this at home, but a double sided board will be cheaper for low volume manufacture. This is only done when you are doing 100k of the same board, and want to shave off fractional cents in material, and can amortise the masks and ink cost over multiple units using a very cheap single side SRBP board.