Murata XBSC Series Assembly page 8

XBSC/UBDC/UBSC/BBSC/ULSC 100 µm & 400 µm -
Assembly by soldering
Solder print material and stencil printing recommendations
Solder pastes SnPb63/37 or SAC305 are usually used and recommended but other materials compatible with the
die pad finishing are also possible.
Depending on the die pad size, powder size could be adjusted. However, type 6 compared with type 3 limits the risk
of tilting of the capacitor (see Figure 2).
ALLOY
Sn63
SAC305
Water soluble and no clean flux can be used. In case of water soluble flux, remove the flux immediately after reflow
to avoid the potential issue of leakage current between pads.
Stencil design rules in function of the quality :
T T
L
W
A solder joint thickness of 40 µm +/-10 is targeted to limit the risk of contact between the solder paste and the side
of the capacitor. Such a contact would have a negative effect and would probably create a high leakage or a short
circuit. Limited solder joint thickness will also avoid an excessive tilting of the capacitor.
For example, design of stencils done by Murata (SAC305 type 6 with 50% of flux):
Silicon Capacitor Type
0201M
0201
0402M
0402
0603
Assembly Note – Ref : ASNUBSC1.6
FBC-0003-01
COMPOSITION
63Sn, 37Pb
96,5Sn, 3Ag, 0.5Cu
INOX LASER: [(L*W)/(2*(L+W)*T)] > 0.66 & W > 1.5*T
NICKEL LASER: [(L*W)/(2*(L+W)*T)] > 0.53 & W > 1.2*T
ELECTROFORMED: [(L*W)/(2*(L+W)*T)] > 0.44 & W > 1.0*T
And in all cases : W > 5 * powder size
Stencil opening size
µm
200 x 130
320 x 150
Diam 114
369 x 260
768 x 300
SOLIDUS LIQUIDUS
183°c 183°c
217°c 217°c
Stencil thickness
µm
50
100
50
125
125
Rev 1.2
Rev. 1.6
COMMENTS
Eutectic
Eutectic
Stencil quality
EXAKUT
TECHNOLOGY
ELECTROFORMED
EXAKUT
TECHNOLOGY
NICKEL LASER
NICKEL LASER
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