CLICpix2 & C3PD Alignment
Marks
I. Kremastiotis, E. Santin, and P. Valerio
CLICdp Vertex Meeting
CERN, December 3rd 2015
Initial proposal from D. Dannheim
overlaid
crosses
Vernier
scale with
1µm fine
resolution

Motivation: Make possible precise alignments between CLICpix2 and C3PD chips
2
Alignment marks at four “corners”
3175.00µm
3234.75µm
3230.50µm
CLICpix2
3261.14µm
3
CLICpix2 bottom marks
bottom left
bump pad center

bottom right
bump pad+via center
“Bump pad” vs “bump pad + via” center alignments possible (using diagonal crosses)
4
CLICpix2 top marks
top left
55.50µm
bump pad+via center
top right
59.75µm
bump pad+via center
5
C3PD marks

2 different alignment marks:

“Empty” cross

Row of 11 rectangles (20 x 2 µm2) with
9µm pitch (Vernier marks)

Use of top metal (AM)

Polysilicon, diffusion and M1-MT
exclude layers added on the marks
to avoid any blurring from the
dummy filling pattern

DRC clean
4um
10um
20um
90um
20um
2um
9um
6
C3PD top and bottom marks

Top side of matrix:


16um
Vertical distance from edge of the matrix to
the center of the cross: 12.5 µm
(center of cross aligned to the center of the
top pixel)
Vertical distance from the center of the cross
to the center of the first (top) bar: 16 µm
Center of row aligned to the center of cross
C3PD
matrix

12.5
top side

43.07
Bottom side of matrix:


Horizontal distance from edge of the matrix to
the center of the cross: 12.5 µm
Horizontal distance from the center of the cross
to the center of the first (right-most) bar: 16 µm
C3PD
matrix
12.5
55.5um
bottom side
16
7
C3PD global view


Alignment marks matching the
CLICpix2 pixel layout for a
flip-chip assembly
Same cross-to-cross spacing
as in CLICpix2
top alignment marks
(match the bottom marks on
CLICpix2)
bottom alignment marks
(match the top marks on
CLICpix2)
3.2 mm
Matrix
C3PD
CLICpix2 + C3PD bottom marks overlay (“bump pad + via” alignment)
bottom right
marks aligned
marks non-aligned
bottom left
C3PD bump pad: 20 x 20 µm2
9
CLICpix2 + C3PD top marks overlay (“bump pad + via” alignment)
top left
top right
cross aligned
vernier marks aligned
cross non-aligned
vernier marks aligned
10
CLICpix2 + C3PD bottom marks overlay (“bump pad” alignment)

bottom right
marks non-aligned
marks aligned
bottom left
For “bump pad” alignment, one of the two chips should be shifted by 4.25 µm
11
CLICpix2 + C3PD top marks overlay (“bump pad” alignment)
top left
cross non-aligned
vernier marks aligned
top right
cross aligned
vernier marks aligned
12
Thank you for your attention!
Backup slides
Knowledge from CLICpix1
CLICpix1
3µm
SiO2
2.125µm
SiO2
15
Bump pad + via center (partial coverage)
AP width [µm]
C3PD bump pad
y = 11.5 µm
y [µm]


Assuming the C3PD bump pad has dimension of 20 x 20 µm2, the CLICpix2 bump pad + via center
is at 11.50 µm instead of 11.25 µm (= 22.5 µm/2). This center would maximize the area overlap
between the two bump pads, and hence the coupling capacitance (assuming the glue and
passivation layer have approximately the same dielectric constant)
We are currently using 11.25 µm (i.e. bump pad + via height divided by 2) for simplicity, and also
because the alignment machine has a precision of only ~ 1 µm
16
AP width [µm]
Bump pad + via center (full coverage)
y = 12.167 µm
AL = 120 µm2
AR = 120 µm2
y [µm]

Bump pad + via center is at ~12.167 µm instead of 11.50 µm, assuming a C3PD
bump pad scenario covering the whole CLICpix2 pad
17