Can you use thicker PMMA like A8 or A10 (950 mol weight)?

Thanks.

Saydur

---- Original message ----
>Date: Tue, 8 Apr 2008 21:33:07 -0700
>From: "Kvel Bergtatt" 
>Subject: Re: [mems-talk] PMMA etch resistance
>To: "General MEMS discussion" 
>
>wet etch is not an option?
>
>_fm
>
>On 4/7/08, Satish Yeldandi  wrote:
>>
>> Hi all
>>
>> I am trying to etch SiO2 using PMMA as mask. I am using ICP RIE system
>> for plasma etching. My oxide layer is 250nm thick and the substrate is
>> Si. PMMA
>> is 180nm thick. PMMA is not holding as a mask. I am not able to etch SiO2
>> with this thick PMMA. Can anyone suggest me how to etch SiO2 with this
>> thick PMMA as mask.