1 / 12

SU-8 And Its Features

SU-8 And Its Features. Anne Samuel. Contents. Introduction - photoresist - positive vs negative photoresist SU-8 - photosenstivity of SU-8 - process - features - application References. Photoresists. Photoresists consists of three components.

thuong
Download Presentation

SU-8 And Its Features

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SU-8 And Its Features Anne Samuel

  2. Contents • Introduction - photoresist - positive vs negative photoresist • SU-8 - photosenstivity of SU-8 - process - features - application • References

  3. Photoresists • Photoresists consists of three components. - Resin( binder that provides adhesion, chemical resistance etc- poly(cis-isoprene)) - Sensitizer(photoactive compound such as bis(aryl)azide,t-butyl benzoic acid) - Solvent( which keeps the resist liquid)

  4. Positive Vs Negative Photoresists • Positive Photoresists(PMMA) - developer is not a solvent. - resolution is 0.5(mm) and contrast is 2.2 - higher resistance to plasma etching • Negative Photoresists( rubber based resists) -provides good adhesion and tougher films for wet etching. - more sensitive,so faster reaction(exposure energy is 10 mJ/cm^2 vs 100 mJ/cm^2). -contrast is ~ 1.5 - lower % of sensitizer, so these resists are cheaper. - not sensitive to over-developing.

  5. What is SU-8? • EPON SU-8 - a negative epoxy based photoresist - near UV sensitive - consists of multifunctional highly branched polymeric epoxy resin - dissolved in a organic solvent along with photoacid generator. • SU-8 was first formulated at IBM as early as 1982.

  6. What is SU-8? • A single molecule contains 8 epoxy groups in a bisphenol- A novalac glycidyl ether. • 8 in SU-8 means the 8 epoxy groups. • SU-8 polymer structure. <http://www.zurich.ibm.com/st/mems/su8.html>

  7. Photosensitivity of SU-8 • The photo acid generator with the epoxy resin in SU-8 is triarylsulfonium salt. • When SU-8 is exposed to light or photon, it is absorbed and photochemical reaction takes place. • The photochemical reaction produces an acid. <http://www.ee.ucla.edu/~jjudy/classes/ http ee250a/lectures /EE250A_Lecture_09_Thick-Film_Lithography_SU-8_files/frame.htm>

  8. Photosensitivity (cont’d) • The acid formed in the photochemical reaction acts as a catalyst in the exposed regions during post baking exposure (PEB). • To promote a cross linking reaction. • During cross linking, a zipping process occurs between the epoxy groups creating a three dimensional network. • In order for the cross linking to takes place PEB must be above Tg • Cross-linking causes the film to shrink and become more dense. <http://www.ee.ucla.edu/~jjudy/classes/ http ee250a/lectures /EE250A_Lecture_09_Thick-Film_Lithography_SU-8_files/frame .htm>

  9. SU-8 Process • A typical SU-8 process consists of - Spin-coating - Soft Bake - Exposure - Post Exposure bake(PEB)-to cross link exposed regions of the film - Development - Rinse & dry - Hard Bake (or curing-optional) - Imaged material - Remove (optional)

  10. Features of SU-8 • Why should we use SU-8? • Good adhesion • Near UV- Sensitive • Broad range of thickness can be obtainted from one spin with a conventional spin coater (750 nm to 500 mm) • High aspect ratios ( ~15 for lines and 10 for trenches). <http://www.ee.ucla.edu/~jjudy/classes/ee250a/lectures/EE250A_Lecture_09_ Thick-Film_Lithography_SU-8_files/frame.htm>

  11. Applications of SU-8 • Some of the applications include - Electroplating molds - Sensors - Actuators - Micro-to Milli scale structures - Microfluidic channels

  12. References 1. Judy, Jack. “Thick film Lithography & SU-8”. 2003. <http://www.ee.ucla.edu/~jjudy/classes/ee250a/lectures/EE250A_Lecture_09_Thick-Film_Lithography_SU-8_files/frame.htm 2. IBM Research -Zurich Research Laboratary. “ Epon SU-8 Photoresist”. <http://www.zurich.ibm.com/st/mems/su8.html> 3. Micro.Chem.“Nano-SU-8: Negative Tone Photoresist Formulations” Feb.2002. <http://www.ee.byu.edu/cleanroom/SU8_2-25.pdf> 4. Lorenz,H, Guerin,L et.al . “ SU-8 Technologies at EPFL”. June 2002. <http://dmtwww.epfl.ch/ims/micsys/projects/prtop.html>

More Related