Lithography policy changes

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There are many changes to the lithography processing at the LNF, mainly involving the addition of new manual spinners and developers. There are also policy changes regarding photoresist handling and other lithography procedures. If you perform manual lithography in the lab, please read the following closely. If you have any questions or concerns, please contact Rob Hower or Kevin Owen, or attend the weekly planning meeting which currently takes place Tuesdays at 1:30pm in the LNF conference room EECS 1340.

New lithography tool training procedure

The lab has implemented a Lithography training session for users wishing to be authorized on several of the lithography tools in the lab. The purpose of this session is to increase the knowledge of users regarding lithography processing and to inform them of the various policy changes to such processing in the LNF. Additionally, basic training on some features that are used across different tools will be included. This session is only required once for checkout on any of these tools. Tools requiring this checkout include the CEE 100CB Spinner, CEE Developer 1, CEE Developer 2, and YES Image Reversal Oven.

Changes to manual photoresist spinners

There are several changes to the manual photoresist spinners that will occur in early 2013. Several of the older spinners will be taken offline to make room for new automated dispense spinners. These will allow the lab to keep track of photoresist usage and reduce waste. We will be keeping at least one fully manual spinner. Below is a list of changes regarding the spinners:

  • The CEE 100CB spinner has been moved to 1440C and interlocked. For authorization, please read the wiki page for the tool.
  • The Headway Spinners are offline and have been removed.
  • New CEE 200X photoresist spinner 1 and CEE 200X photoresist spinner 2 spinners are installed and will be released in summer 2013. Please complete the survey on the online services if you would like input on what photoresists will be plumbed into the tools.
  • The Solitec Spinner is planned to be taken offline, likely in summer 2013.

Lab supplied photoresists

The current system of users pouring small bottles of photoresist will be going away. The new CEE 200X spinners mentioned above will be plumbed with lab standard SPR 220 and S1800 series photoresists. These and other supported resists are supplied in syringes that can be used in all of the manual spinners. These syringes are available now and an explanation of how to use them can be found in the Lithography Handbook. Beginning in August 2013, we will start pulling large photoresist bottles from the lab. PMMA will be available in the LNF store by the end of June. In July, the remaining photoresist syringes will become available for purchase.

Photoresist development policies

The recommended method of manual photoresist development in the LNF CEE Developer 1 or CEE Developer 2. These are online and plumbed with AZ 726 and CD-30. If you wish to be authorized, please read the SOP and checkout procedure on the wiki page.

Manual development in beakers will be moved from the Base bench in 1440B to Acid-61 in 1440C, which will be converted into a Base bench in June 2013. This bench will be interlocked and the chemical cabinet will be locked unless the bench is reserved.

HMDS priming

Vapor prime HMDS is the preferred method of coating wafers with HMDS adhesion promoter. There are currently vapor prime ovens in the ACS 200 cluster tool, and in the YES Image Reversal Oven. For preparation for manual spinning, we recommend the latter. This tool is very easy to use and takes about 15 min to process up to 25 wafers, or a large quantity of pieces. If there is a large demand for the oven, we will be installing another oven in 1440C to supplement it. Liquid HMDS will still be available, although it will likely move into syringes along with the photoresists, as described above.

Piece part lithography

The standard tool for contact exposure of pieces is the MJB3-2. All piece users currently using the MA-6 or MA/BA-6 should begin thinking about moving their processes. Certain exceptions will be made, mainly for users who require backside alignment. Please contact the tool engineers if you have any questions.