Hi Bill Chow, Try AFM . On Thu, May 15, 2014 at 7:02 PM, yutchow2@gapps.cityu.edu.hk < yutchow2@gapps.cityu.edu.hk> wrote: > Thanks for your suggestion. Unfortunately， I don't have phase contrast > microscope. In addition, the first layer structure was not clear to see and > difficult to observe both the alignment mark on the first layer and on the > mask clearly at the same time. Are there any usual practice to locate and > align the second layer with high accuracy? I am using Karl Suss MA6. Thanks. > > Regards, > > Bill > > > ------ 原有訊息------ > 寄件者： Gareth Jenkins > 日期: 週四, 2014年5月15日 8:30 > 收件者： General MEMS discussion; > 主旨：Re: [mems-talk] Alignment problem with Multilayer SU-8 fabrication > > I used to use a phase contrast microscope to align layers. > Once I found the alignment marks under the microscope, I would manually > scratch the resist with a scalpel (which needs a steady hand). Then I could > align the second layer to the scratches on the mask aligner. > > > On 14 May 2014 17:14, Bill Chow wrote: > > > Dear all, > > > > Recently, I am working on a two layer SU-8 structure. All the process are > > followed with the suggested procedures. However, the problem appeared > when > > I try to look for the alignment mark, after I have spin coated and > prebaked > > the second layer of SU-8, it is difficult to locate the first layer > exposed > > features. > > > > First layer thickness : 3.7um > > Second layer thickness : 17 - 20um > > > > I found that it is extremely difficult to locate the first layer pattern > > under the microscope after I have coated the second layer, despite it can > > be seen be naked eye.... Sometimes if there are some defect or bump in > the > > 2nd layer above the alignment mark, then it can be seen clearly. However, > > it is a random process and will affect my pattern. Are there any ways to > > improve the visiblity of the alignment mark after I have coated the 2nd > > layer? Thanks. > > > > Regards, > > > > Bill > > > > _______________________________________________ > > Hosted by the MEMS and Nanotechnology Exchange, the country's leading > > provider of MEMS and Nanotechnology design and fabrication services. > > Visit us at http://www.mems-exchange.org > > > > Want to advertise to this community? See http://www.memsnet.org > > > > To unsubscribe: > > http://mail.mems-exchange.org/mailman/listinfo/mems-talk > > > _______________________________________________ > Hosted by the MEMS and Nanotechnology Exchange, the country's leading > provider of MEMS and Nanotechnology design and fabrication services. > Visit us at http://www.mems-exchange.org > > Want to advertise to this community? See http://www.memsnet.org > > To unsubscribe: > http://mail.mems-exchange.org/mailman/listinfo/mems-talk > > _______________________________________________ > Hosted by the MEMS and Nanotechnology Exchange, the country's leading > provider of MEMS and Nanotechnology design and fabrication services. > Visit us at http://www.mems-exchange.org > > Want to advertise to this community? See http://www.memsnet.org > > To unsubscribe: > http://mail.mems-exchange.org/mailman/listinfo/mems-talk > -- Thanks & Regards, Sangeetha VS. _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk