Spin Coating Theory

Spin coating is a procedure used to deposit uniform thin films to flat substrates.  Usually a small amount of coating solution is applied on the center of the substrate, which is either spinning at low speed or not spinning at all.  The substrate is then rotated at high speed in order to spread the coating material by centrifugal force.  A machine used for spin coating is called a spin coater, or simply spinner.  Rotation is continued while the fluid spins off the edges of the substrate, until the desired thickness of the film is achieved.  From Wikipedia, and Columbia University.


SCK-300P + Vacuum Chuck

The SCK-300P makes use of the same innovative vacuum chuck design of the SCK-200P, but now uses a custom Closed-loop Motor Interface Module (MiM), and Brushless DC motor.  This results in an increase speed resolution (+/- 5 vs. +/- 20 rpms for the SCK-200P), and the ability to directly set the desired speed, in 50 rpm increments, from 500 to 8,000 rpms.  Like previous models, it comes with everything needed for R&D spin coating work of small substrates.  A suitable Vacuum System needs to be provided by user. View video to see it in action. User Manual (pdf) / Vacuum System Setup Instructions (pdf) / Specification.

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The SCK-300 Spin Coater Kit is a fully assembled, modular, “Home Built” spin coater that builds upon the SCK-200 design, but incorporates the same Motor Interface Module (MiM) and brushless DC motor used in the SCK-300P model.  As such, it now has a speed resolution of +/- 5 rpms vs. +/- 200 rpms for the SCK-200, and the ability to directly set the desired speed from 500 – 6,000 rpms, in increments of 50 rpms.  View video of it in action.  User Manual (pdf) Specification.

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SCK-300P With Micro Vacuum Pump

Recently we noticed a number of eBay listing for new low-cost (~$30), micro vacuum pumps which look like they might work with the SCK-300P.  Typically, such small pumps do not have the required air-flow/vacuum pull, but their specifications suggested these do.  After ordering a few units from China, and a two week wait, our testing (see video) indicates that work.   Standard 75 mm x 25 mm microscope glass slides are held firmly at speeds up to 5,000+ rpms.   That performance should fine for most spin coating work.
So if you are looking for a cheap and compact vacuum pump system, that’s one way to go.  All that’s needed is to mount them on a suitable platform (A plastic box cover with rubber bumpers was used), and wire them up to a 5 amp/12V power supply with an Inline Switch.  These little pumps are a bit noisy though, and we are not sure how long they will ultimately last.

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The SCK-DIY is not an assembled unit, but rather instructions for anyone who wants to build their own “Home Built” spin coater.  It based largely on work done developing a versatile, high precision, Raspberry Pi controlled spin coater.  In the end, it was not cost effective to go into production with this unit, so we figured why not provide plans, along with control software, for a simplified version to the community to hack on.  Checkout the instructions at this Blog.  Please note that instructions are provided as is, and we offer No Help With Assembly.  

Click on image for a larger view or take a look at video.