hello,

maybe the right method to fabricate your two layer is, to process one by
one, because if you expose the second layer without developping the
first one, you will have just the second layer channels because you have
exposed all the rest of your wafer!

there is another method to fabricate two SU8 layers : you can pattern
the first one on a wafer and the second one on other wafer and laminate
the both at high temperature.

Alaa


Gareth Jenkins a écrit :
> I am not 100% sure I understand what you're trying to achieve but generally
> you should spin & expose each layer and then develop in one go at the end.
>
> On Sat, Mar 6, 2010 at 21:46, Jean Lo  wrote:
>
>
>> Hi,
>>
>> I am trying to fabricate a device with 2 layer of SU8.
>> The first layer is just a simple straight microfluidic channel which is
>> around 200 um wide.
>>
>> I am planning on fabricate a second layer of SU8 on the top of the
>> microchannel with a series of blocks along the length of the microchannel.
>> The second lyaer of SU8 needs to be really thick since the PDMS thickness
>> is
>> going to be in between the first layer and the second layer,
>> so that I will have holes within the microchannel.
>>
>> My question is that what might be the better process to process the second
>> layer of SU8?
>>
>> Should I spin-coated and expose the first layer following a second layer
>> spin-coated and exposure and develop the whole wafer all at once,
>> or should I spin-coated, expose and develop the first layer and process the
>> second layer afterwards?
>>
>> Any suggestion and opinions would be greatly appreciated.
>>
>> Thanks a lot!
>>
>> Jean

--
Alaa el dine ALLOUCH
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