# Wafer Cleaving SOP

![](https://lh5.googleusercontent.com/WrEL2P-eEcnc9SOkBt02c8e-ecVWGcs1B4FsI21OduabHmqpJgFpk_zSAcmn05p0HwtcVK423fw0AwmjT9I0H0KFIwlPkjUMtVIV0alYvtHm6fUKZWAhBL0zuJbhBJ6Oa9xBKRRFN5y--xzKgJboR7w)

## Purpose

We pre-dice wafers in order to: 

* Limit the size of our DIY machines 
  * Decreases the necessary movement range of nanpositioners
  * Other machines can be sized down
* Increase experimental throughput
  * Decrease cost of each raw materials
  * Decrease risk of breaking chip
  * Ease chip handling

## Best Practices

See [this video](https://www.youtube.com/watch?v=MxjppY1iA4A) for reference

1. Open this [central chip count](https://docs.google.com/spreadsheets/d/1MrqtnkHcNr5hekHpQHusBZJG4nrdcxDz7Yg5Emn9BMQ/edit#gid=0) sheet, claim the next available chip number, open the blank chip view sheet for that specific chip number and record all subsequent process data into it.
2. Use a [diamond tipped scribe](https://docs.google.com/spreadsheets/d/1x1SKlcFd_YezeLDJ4mFUUFoybHkMIZpcm6by8iPltEY/edit?usp=sharing)
3. Lay the wafer on a hard, steady surface
   1. If the surface has some give, it will act as a spring when pressure is applied from the scribe
4. At an oblique angle, place the scribe tip at the edge of the flat side of the wafer 
   1. Flat edge marks crystal orientation, cleaving should be easier along certain crystallographic directions.
5. Push down, don't think too hard, cleave.
   1. It may also help to press down and drag the scribe tip 1 mm outwards to the edge of the wafer.
6. Don’t move chip around with the diamond scribe to avoid scratches
   1. Use [tweezers](https://docs.google.com/spreadsheets/d/1x1SKlcFd_YezeLDJ4mFUUFoybHkMIZpcm6by8iPltEY/edit?usp=sharing) to move once a cut is made