I want to connect the MEMS device electrically to a PCB through Au wire bonds. I have designed the PCB for the MEMS device to mount on. I would like to know if there is any way I can align and bond my MEMS device to the PCB if I do not have access to a Die bonding machine.

Any help and ideas would be appreciated.

  • 2
    \$\begingroup\$ Hire somebody who does have a wire bonding machine. \$\endgroup\$
    – The Photon
    Jul 5 '17 at 22:41
  • \$\begingroup\$ I actually found a local wire bonder willing to teach me to do it. I didn't break too many dice. Luckily, Hamamatsu gave me a full waffle pack. :) \$\endgroup\$
    – jonk
    Jul 6 '17 at 1:51
  • \$\begingroup\$ I actually have access to a wire bonder, but not the die bonding machine \$\endgroup\$ Jul 6 '17 at 2:07

If you're just talking about mounting the die for a one-off prototype, you can do that freehand with a vacuum tool or tweezers and a small dot of epoxy (silver epoxy is common due to heat transfer and the fact that it's conductive). This was how they did it back before the automated die attach machines. Yield isn't very good, but it works. Ask whoever the tech in charge of your wirebonding machine is for some help, if you don't have a die attach machine presumably they do this on a regular basis.

If you're talking about actually doing wire bonding after die attach, you obviously need a thermosonic gold wirebonding machine. If you don't have access to one, you'll need to get access to somewhere that does (such as a university) or pay somebody to do it for you.

Having a professional shop do both the die attach + wirebond process is relatively cheap - I have had a prototyping shop do it it for a lot charge of under $1000, and they were happy to do a few dozen prototypes for that lot charge. You're also guaranteed that they'll do both the attach and bond jobs correctly, so if something goes wrong you won't be second guessing your mounting job.

You probably already know this, but you should keep in mind that to do chip-on-board you need the appropriate PCB finish - either soft gold or preferably ENEPIG, and the plating will need to be a certain minimum thickness for the bonding process.

  • 1
    \$\begingroup\$ If OP's organization had a wirebonding machine and a tech to operate it, I don't think they'd be asking this question. The steady-handed tech and drops of epoxy could be the solution if they'd forgotten to gold plate their PCB lands. \$\endgroup\$
    – The Photon
    Jul 6 '17 at 0:51
  • \$\begingroup\$ Thank you Peter for your answer. I just got access to the university Au wire bonding machine. However, they do not have a die bonding machine, so I might have to go freehand on the manipulation, alignment and gluing of the die. You also mentioned that you got a professional shop to do the die attach + mounting. Would you be able to share more details on that? Also, thank you for talking about the ENEPIG finish, I have already specified that to my board manufacturer. \$\endgroup\$ Jul 6 '17 at 1:16
  • \$\begingroup\$ I used Quik-Pak in San Diego, but there's lots of places that do microelectronics assembly - you should be able to find somebody close by to you. Since your university has a wirebonding machine, I'd ask the tech in charge of it for help with the manual bonding, if you want to go that route. \$\endgroup\$ Jul 6 '17 at 16:05

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