boundary conditions help

[cristina2]

Hallo, I must model a structure where I have a Silicon die with some thin film material on top. The film is deposited at high temperature, then cooled down. during cooling stresses and strains are developed inside and partially released by system bending (see attachment).
My question is: which kind of boundary conditions should I use for the model ? I cannot just fix all the die bottom (this would not allow it to bend). So I thought I could just fix a single Point (total fix: 3Dof Rotation and 3 dof traslation).
Do you think that is correct ? Else, do you have any other Suggestion ? Thanks

 

[IRstuff]

Typically, die are mounted with either epoxy bond or a metallic eutectic. I don't recall much processing that's done after the die is mounted, though, particularly something that is high stress. Usually, that sort of processing is done prior to die bond.

TTFN
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[corus]

Use symmetry on two planes and fix one point at the centre in the remaining direction.

 

[cristina2]

Hi corus thanks;
(1) could you please be more specific or make a sketch regarding your answer ?
(2) also, assuming that there is no simmetry (in this case there is, but a following case could not have), what is the general way ? If I model the entire block, is it sufficient for me to fix completely only one point ?

 

[dwallace1971]

If the only load you're imposing is thermal, consider a simple set of kinematic constraints to restrict rigid body motion. A quick google search will tell you all you need to know in order to set these up.

"On the human scale, the laws of Newtonian Physics are non-negotiable"

 

[cristina2]

Thanks a lot everybody; with all your suggestions I could find the answer and also learn Basics that will be very useful for me.