Resist adhesion to Borosilicate glass for BOE etching

[Yinxiao Li]

Hi all,
I have had a problem in etching Borosilicate glass using BOE (6:1). As etching continues in the channel, the photoresist near the channel gradually peels off and when etching finishes (100nm), the lateral distance of peeled-off resist is big--about 6 microns. Anybody have a great solution for promote the adhesion? Currently I use spinned HMDS to promote adhesion. The resist is Shipley 1813 and I hard bake it for 1hour at 115C before wet etching. Thanks!

 

[phyzguy]

In my experience, what you are doing should work. Are you sure the glass is clean and dry before you apply the HMDS? I suggest a piranha clean followed by a bake above 100C before applying the HMDS. Another suggestion is to try a more dilute BOE (10:1). If these don't work then I am stumped.