Solder Paste Type
Cree LED strongly recommends using “no clean” solder paste with XLamp ML LEDs so that cleaning the PCB after soldering is not
required. Cree LED uses
internally.
Cree LED recommends the following solder paste compositions: SnAgCu (tin/silver/copper) and SnAg (tin/silver).
Solder Paste Thickness
The choice of solder and the application method will dictate the specific amount of solder. For the most consistent results, an automated
dispensing system or a solder stencil printer is recommended. Cree LED has seen positive results using solder thickness that results in a
4-mil (102-μm) bond line, i.e., the solder joint thickness after reflow soldering.
After Soldering
After soldering, allow XLamp ML family LEDs to return to room temperature before subsequent handling. Premature handling of the
device could result in damage to the LED.
Cree LED recommends verifying the solder process by checking the consistency of the solder bond of several trial PCBs after reflow. After
shearing selected devices from the circuit board the solder should appear completely re-flowed (no solder grains evident). The solder
areas should show minimum evidence of voids on the backside of the package and the PCB.
Cleaning PCBs After Soldering
Cree LED recommends using “no clean” solder paste so that flux cleaning is not necessary after reflow soldering. If PCB cleaning is
necessary, Cree LED recommends the use of isopropyl alcohol (IPA).
Do not use ultrasonic cleaning.
Moisture Sensitivity
XLamp ML Family LEDs are shipped in sealed, moisture-barrier bags
(MBB) designed for long shelf life. If XLamp ML Family LEDs are
exposed to moist environments after opening the MBB packaging but
before soldering, damage to the LED may occur during the soldering
operation. The derating table at right defines the maximum exposure
time (in days) for an XLamp ML Family LED in the listed humidity and
temperature conditions. LEDs with exposure time longer than the time
specified below must be baked according to the baking conditions listed below.
P
CORRECT
X
WRONG
Temp.
Maximum Percent Relative Humidity
30%
40%
50%
60%
70%
80%
90%
35 ºC
-
-
-
17
1
.5
.5
30 ºC
-
-
-
28
1
1
1
25 ºC
-
-
-
-
2
1
1
20 ºC
-
-
-
-
2
1
1
XLAMP
®
ML FAMILY LED SOLDERING & HANDLING
© 2010-2021 Cree LED. The information in this document is subject to change without notice. Cree
®
and the Cree logo are registered trademarks, and
the Cree LED logo is a trademark, of Wolfspeed, Inc. XLamp
®
is a registered trademark of Cree LED. Other trademarks, product and company names
are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. This document
is provided for informational purposes only and is not a warranty or a specification. For product specifications, please see the data sheets available
at www.cree-led.com.
CLD-AP50
REV 10
5