What you should care about

What you should care aboutEdit

Optical lithography

ALWAYS think your masks for only one full wafer, and not for several pieces of wafers for different applications. Optical lithography is made for full wafers, and doing it for small pieces is anyhow unpractical. But more important, is that when you try to expose a chip which is not centered on your mask, then you cannot ensure flatness between your chip and  your mask, and the lithography is spoiled.
So the word is: don't be greedy. Order 2 masks if necessary.

e-line exposure

- do not make big polygons (cf: 21/12/2011). There will be a 'cormeb error' when trying to split the polygon prior to exposition of your gds, and the polygons will not be exposed.
Instead, you should fracture the polygons manually.
'big' is to be defined exactly. This might be a question of number of points

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Bonding Parameters

• On the TPT HB10 bonding machine at SPEC:

First bond on Au:
P US =  400 à 480 mW
time =  200 ms
Force = 300 à 350 mN (NB: 350 trop fort)

Second bond on Nb (works with 50nm Nb without sticking layer):
P US = 400 mW
time = 150 ms
Force = 300 mN

From Nb to Nb: 
bond 1 : 480 / 200 / 250
bond 2 : 480 / 200 / 250

observation: Il faut faire en manuel, avec un mouvement de retour au ras de la surface avant de le 2è bond pour avoir un profil en boucle pour le fil (donner un peu de souplesse dans le fil, car les distances entre bond sont très courtes), et éviter que le 1er bond ne se décolle sous la contrainte. ça permet aussi d'être sûr qu'on ne court-circuite pas la piste au-dessus de laquelle on passe.

• On the CSNSM westbond 7400B: