Title: Hand Rubbing of Polyimide coated slides

Revised: 2/2001

Purpose: This standard operating procedure (SOP) describes the preferred procedure for hand rubbing polyimide coated substrates to obtain alignment layers.

Preparation: Read and understand the Access Protocols (SOP #1) and the Gowning Procedures (SOP #2 or 2a). This operation will be performed in the cleanroom so the whole procedure for gowning must be followed.

Precautions: This is generally a safe activity. The most serious precaution is that you not rush or in way damage the alignment polyimide layer through an inadvertent rub, scratch, or nick.

Procedure:

  1. Locate the hand rubbing machine. It is just to your left as you enter the class 1000 section of the LCDRF cleanroom. It is on top of a Blue-M oven. The rubbing machine consists of an aluminum frame, a few pieces of glass, tape, and a black "velvet" cloth attached to a rectangular aluminum block or to a stack of glass. (These last two pieces will be called the "rubbing block."). The aluminum block is roughly 5 inches by 6 inches by ½ inch thick, while the glass block is roughly 3 inches wide, by 8 inches long. You will also need a marker (such as a "Sharpie") to mark the rubbing direction.
  2. The first step is to set up the glass plates to form a "jig" for the slides you will be rubbing. Generally, a set-up like the following, with the jig pieces held by tape, is fine:

  1. Hand rubbing uses very little pressure, therefore it requires multiple passes, ten (10) is a good number, do not go below 7 passes.
  2. Blow of the velvet-rubbing block you will use with compressed N2. This is to remove any old glass pieces or the like that may be embedded in the cloth.
  3. Mark the direction of rubbing on the unpolyimide coated side of the substrate before you set it in the jig to rub.
  4. Line up the piece so that it is centered on the arm of the machine.
  5. Put the rubbing block on the far piece of jig glass so that it is noton the piece you wish to rub. Line it up so that it is parallel to the "arm" on the aluminum frame that will push it forward, and covers the whole substrate you wish to rub.
  6. In one continuous motion, pull the handle of the machine towards you. Once the far end of the rubbing block is past the near side of the piece you are rubbing, pick it up.
  7. Move the handle of the machine back to its starting point, place the rubbing block back on the jig piece, and repeat step 7.
  8. Repeat step 8 until you have rubbed the slide at least seven times, preferably ten times.
  9. Clean up the area when you are done.