1. Department of Physics, University of Michigan
SNAP NIR Detector Packaging Development: First results from FEA of SiC / EA9361 / Moly Package
Bruce C. Bigelow
Department of Physics, University of Michigan
30 June 2005

2. FEA of SiC Package with insert
Motivations:
Investigate effects on NIR package due to epoxy bonded moly insert
Sub-model of insert and surrounding SiC
Material CTE values included as a function of temperature ( K)
Temperature excursion from 295 to 120K
Still need epoxy (Hysol 9361) E(T) data
Moly insert (TZM later)
Nominal bond line of 200 microns
First results are for insert offset by 50 microns in ideally located hole
Package depth is 8mm
Insert height is 6mm
Air gap above insert 0.5mm
30 June 2005
B. C. Bigelow -- UM Physics

3. UM SNAP NIR Package Design
30 June 2005
B. C. Bigelow -- UM Physics

4. Full geometry FEA model (1/2 shown)
Note epoxy bond variation due to insert decentering
30 June 2005
B. C. Bigelow -- UM Physics

5. Constraints on base of insert
30 June 2005
B. C. Bigelow -- UM Physics

6. Equiv. Stresses in materials (Pa)
30 June 2005
B. C. Bigelow -- UM Physics

7. Equiv. Stresses epoxy (Pa)
30 June 2005
B. C. Bigelow -- UM Physics

8. Equiv. Stresses in SiC (Pa)
30 June 2005
B. C. Bigelow -- UM Physics

9. Opt. axis motion in SiC (m)
30 June 2005
B. C. Bigelow -- UM Physics

10. Deflection in top surf. of pkg (m)
30 June 2005
B. C. Bigelow -- UM Physics

11. NIR Package with insert FEA
Conclusions:
First results only – more coming as a function of insert offset, mat props, etc
Stresses in all materials are very low
Deflections at top of package are negligible
30 June 2005
B. C. Bigelow -- UM Physics