Spin Coating

2/27/97

A while back I read a paper in which a test specimen was prepared

for nearfield scanning microscopy by spin coating beads mixed in

polyvinyl alcohol onto a coverslip. They gave times and RPM's,

and quoted a resulting sample thickness of tens of nanometers.

Does this mean the coverslip is placed on the bottom of a swinging

bucket centrafuge rotor, sample placed on the coverslip, and spin?

Or is the coverslip in some other orientation? Is there a special

"spin coating" apparatus?

Edward J. Huff

huffe@carbon.chem.nyu.edu

Spin coating is very common in microlithography, all photoresists are put onto

wafers in this way, so there is a "spin coating apparatus." It consists of a

flat chuck onto which you would place the slide flat. A vacuum holds the slide

down onto the chuck. You pour some liquid onto it and spin at at as constant an

RPM as possible for about 30 seconds. 3000-5000 RPM is normal. The more

viscous the fluid the thinner the resulting layer. This is probably the

procedure they used.

Gd Skidmore

skidm002@maroon.tc.umn.edu

Spin coaters are common in the semiconductor industry. Basically, they are

a high speed motor with a vacuum chuck attachment on the top of the shaft.

The substrate is held flat to the top of the shaft by the vacuum. Doped PVA

films may be spun to thicknesses of ~>10 nm easily. Depending upon the

viscosity of the media you might try values of 5,000 RPM for ~ 30 seconds.

Neal Nicklaus

nnicklaus@nova.sarnoff.com

Edward

Spin coating is more like setting a cover slip on the center of a record

player and applying a liquid while it is rotating.

We use a spin coater manufactured by Headway Research from Garland, Texas.

Ed Basgall

Penn State Univ.

Dept. of Chemistry

University Park, PA

edb@chem.psu.edu