How to cut silicon wafer - Page 1
Forum section: electronics / projects

author: blueskull
author_rank: Unknown
timestamp: August 29, 2016, 03:53:30 am
content: Is there anyone here knows how to dice a silicon wafer with heavy (up to 0.5 oz) copper electroplated?I know UV/blue laser can dice silicon, but what about the metal? I can not afford a Q switched laser, that's for sure.I tried SiC cutting tool, and it works, but the yield is ultra low, I constantly chip and break the wafer.Diamond saw seems promising, but since I do not have one, I need to find a cheap source for a precision diamond saw.So, any suggestions? Any ideas are very welcomed and appreciated.

author: Berni
author_rank: Super Contributor
timestamp: August 29, 2016, 05:31:14 am
content: That is a bit of an unusual thing to be doing at homePerhaps a better idea is to use a high speed cutting tool to just score a line on the back side and then break the wafer along the line sort of like how cutting glass works.

author: singapol
author_rank: Frequent Contributor
timestamp: August 29, 2016, 05:38:32 am
content: After brousing a bit, a dicing saw is out of your budget to it's back to the primitive scribing method where youscribe a line and the break the silicon. I believe by SiC (silicon carbide) you used a glass cutting tool with a SiC beveled edge round disk? Well traditionally wafer fabs used a diamond tip tool much like a pencil.SearchAlibaba using the term diamond pen and you will know what I mean. Diamond is definitely much harder than Slicon carbide so cuts better as silicon is technically "glass". I think scribing both sides , copper and silicon will give better results but of course much depends on your skill and precision.

author: rs20
author_rank: Super Contributor
timestamp: August 29, 2016, 05:58:10 am
content: Quote from: singapol on August 29, 2016, 05:38:32 amI feel like the 0.5oz Cu would form an annoyingly strong foil that is resistant to scribing?

author: Ian.M
author_rank: Super Contributor
timestamp: August 29, 2016, 06:24:12 am
content: Would it be possible to etch the copper away along your intended cut lines before cutting?

author: m98
author_rank: Frequent Contributor
timestamp: August 29, 2016, 07:55:45 am
content: Maybe you have some solar cell research institute in reach, they have dicing saws and will probably do it for free when you convince them with your project.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 29, 2016, 09:37:10 am
content: There was a recent video of someone putting a paper disc in a circular saw-I wonder if a similar approach with fine abrasive paper might work.

author: m98
author_rank: Frequent Contributor
timestamp: August 29, 2016, 01:35:07 pm
content: Actually, the real blades used in dicing saws don't seem to bethatexpensive:http://www.mtixtl.com/diamondblades.aspxSo you might be able to construct a fixture for such a blade for a normal table saw/a dremel.

author: Kevman
author_rank: Regular Contributor
timestamp: August 29, 2016, 04:58:12 pm
content: https://mightyohm.com/blog/2009/07/tonys-diamond-chop-saw-part-1/

author: SeanB
author_rank: Super Contributor
timestamp: August 29, 2016, 05:00:57 pm
content: Look for a lapidermists saw, used to cut jewels and other semi precious stones. Best to look for jewellery saws to do this, they have the same problem of needing to cut hard expensive items.

author: TerraHertz
author_rank: Super Contributor
timestamp: August 30, 2016, 02:13:31 am
content: I recall seeing a video on IC wafer fabrication many years ago, in which the small square dies were broken apart cleanly by scribing, then placing the wafer on a slightly resilient surface (can't recall if they said what it was) and manually rolling a large polished steel cylinder across the back, with some pressure applied. Rolled across once in each of the two directions for fracturing along the scribe lines.The cylinder was maybe 2 to 3 inches diameter, from memory.I think the wafer was placed 'component' side down, and presumably the scribe lines were on that side too.As with glass cutting, the scribe lines would have to be very clean and uniform (ONE stroke, never go back over the line), then the fracturing pressure also has to be very uniform. Or you get a jagged break line. It might be worth making a simple tool something like a wall tile cutter, to scribe the lines in a controlled way.When you are creating the mask to electroplate your copper electrode lines, can't you mask them to leave copper-free areas where the wafer can be scribed? If you are not using a photo-mask, how do you get those alternating strips?

author: CM800
author_rank: Frequent Contributor
timestamp: August 30, 2016, 10:03:11 am
content: Have a look at this, it may be suitable:http://www.mtixtl.com/diamondsaw-SYJ-40.aspx

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: August 30, 2016, 07:23:51 pm
content: I've gotten good results with these blades-http://www.lopacki.com/lopacki/sawblades/but I don't know where they will ship. If you need a thinner kerf, you'll have to get some real surplus dicing saw blades. Warning- the thin ones are fragile! It isn't hard to build a dicing saw with whatever linear slides/stages you can come up with. The base can be hard maple and common threaded rod is accurate enough for most purposes, certainly for the elevation. The feed in the cutting direction should be by hand, not screw.

author: helge
author_rank: Regular Contributor
timestamp: December 09, 2016, 08:45:32 pm
content: Hello there! I might be having a very similar issue (I basically need a structure with a 2D array of pillars but can't find someone to run that on a stereolithography printer) so my idea is to cut lamellae, add stabilizing glue, cut lamellae perpendicular to previous orientation and dissolve the glue again. Maybe a bit too complicated though.I ran across these hubless dicing blades starting at 0.001" - 0.002",https://www.ukam.com/dicing_blades.htmlmaybe they are suitable for the matter discussed above?

author: pigrew
author_rank: Frequent Contributor
timestamp: December 11, 2016, 01:30:14 am
content: Another thing to think about i the crystal orientation. Silicon will break cleanly in certain crystal directions. There should be notches or flats designating the orientation of the wafer.We usually just break the wafers into pieces (without a saw). If done with the proper orientation, the yield can be pretty good. We have a tool with a slot cut out, and press down on the wafer over the slot.

author: RoGeorge
author_rank: Super Contributor
timestamp: December 11, 2016, 07:17:59 am
content: Never tried cutting silicon wafers, but I cut a thin glass sheet with scissors without breaking/chipping it.The trick is to keep the material completely dived (at a depth at least 10-20 cm deep) under water. Water will dump the strong vibrations of the brittle sheet to be cut.

author: amyk
author_rank: Super Contributor
timestamp: December 11, 2016, 02:57:14 pm
content: Quote from: helge on December 09, 2016, 08:45:32 pmThat link quotes a minimum thickness of .0003" (0.0076mm). How can you even handle those blades without immediately breaking them

author: helge
author_rank: Regular Contributor
timestamp: December 17, 2016, 05:14:05 pm
content: @amyk gotta buy them in packs of 5 ;-) The worst will be getting them on the hub and properly centered. I've seen this done only once during an internship. The foils themselves are quite springy and can bend to some extent and then you gotta have some luck