How can I solder and glue extremely small components?

[0xDEADBEEF]

Today I have soldered my first 0603 metric smd device to wires under the microscope. This is extremely tedious. 0.04 mm dia wire is readily available, and I know for devices like magnetic heads in hard disks, these things are being done commercially.

How do they do it? How do they solder and glue on this size? I couldn't really find anything on the web. The sharpest soldering irons are still .1 mm wide, solder wire is almost always thicker than .5 mm. Laser soldering also seems thicker.

Are there micromanipulators with integrated soldering irons? How can you deposit drops of glue with .1 mm width or deliver tiny amounts of tin? Are there capillaries thinner than say .2 mm outside (syringes are thicker)

The only thing coming close to what I need is wire bonding, but it's not very compatible with most surfaces and materials.

It all burns down to: Can I buy this somewhere, or is it all custom build to fit the job?
How do others do it, can you point me to papers?

 

[Maccara]

Well, you don't usually do this by hand on a large scale, especially not with an iron (some hot air rework station is much more suitable).

Automated pick&place and reflow soldering is usually used to automate on commercial scale.

See for example http://en.wikipedia.org/wiki/Surface-mount_technology#Assembly_techniques".

 

[0xDEADBEEF]

I understand how it is done when one uses the usual smd process. But there are people out there who solder these wires like here: http://upload.wikimedia.org/wikipedia/commons/7/75/Hard_disk_head.jpg. Also someone is producing these tiny resistors and other devices, and how they coat the ends with the solder is still a mystery to me. In the end it will probably all be done with customized machines, but they also need to do some prototyping don't they?

 

[Phrak]

In my current environs we require hand soldering of all components to JSTD-001, class 3 plus some. Are you soldering to PC pads or to wires? I could ask around for some techniques.

By the way, I believe that part size is in inches (0.060" x 0.030"), rather than metric.

 

[Maccara]

Not sure about "best" technique for soldering wires, but 0603 components are still pretty trivial to handle with hot air, flux and solder paste. Some examples (various techniques): http://amiga.serveftp.net/SMD_soldering.html" .

Those examples are for a bit larger pitch, but works for smaller components too, as you don't need to be too exact when applying solder paste (see "Replacing SOIC" from above link where paste is liberally applied).

Using flux helps a lot too.

 

[0xDEADBEEF]

In my current environs we require hand soldering of all components to JSTD-001, class 3 plus some. Are you soldering to PC pads or to wires?

To wires mostly. If I can just drop the component on the contacts and bake it, that would be easy, but wires tend to be under a bit of tension.

[...]
By the way, I believe that part size is in inches (0.060" x 0.030"), rather than metric.

If you want imperial part sizes it is 0201 the second smallest there is. I really mean soldering to dust :)

 

[Maccara]

If you want imperial part sizes it is 0201 the second smallest there is. I really mean soldering to dust :)

Sorry, I missed completely the sizes and just assumed imperial 0603. :)

That indeed is quite annoying to solder. I gather one can pretty much forget wire type solder and paste is a must. Applying the paste is also a bit more complex at that pitch, but some have used stencils to help that and for example a sharpened toothpick to hold the parts in place. Of course, helps if you have only standard sized parts and may not be useful when you try to apply the same to wires.

Personally, I have not had the "pleasure" to hand-repair that small, so can't speak from experience really, but a colleague pointed me to http://www.delorie.com/pcb/smd-challenge/" which has some small parts in it and the "instruction sheet" on that site contains some tips for the soldering.