Silson Products

Lithography Wafers

For many applications which require post-processing of membranes, the customer may prefer to be supplied with an entire intact wafer which can be separated into individual frames once the additional processes are complete.  This is particularly useful for photoresist spinning so that more uniform coatings can be obtained and also for some coating processes so that a single deposition is required instead of multiple coatings of individual membranes.  These intact wafers are referred to as “lithography wafers”.

For photoresist spinning, regular spinners and vacuum chucks can not be used as this will cause the membranes to either break or deform so that the resist is thicker in the membrane areas.  The solution is to use non-vacuum chucks which hold the wafer mechanically or develop special holders in conjunction with custom mask design so that vacuum is only applied in areas where there are no membranes. 

Particular care must be taken when handling lithography wafers as the presence of the etched separation lines and the membranes make them exceeding fragile.  Silson can not guarantee that a lithography wafer will contain 100% intact membranes so for spinning applications they are not suitable for large and thin membranes.

Lithography wafers are available with silicon nitride, silicon and silicon carbide membranes, please contact us with your precise requirements.

If a whole wafer of membranes are not required then an intermediate solution is to use multi-frame arrays or MFAs

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