LUMILEDS LUXEON Neo User manual

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AB172 LUXEON Neo 0.5mm2Application Brief ©2018 Lumileds Holding B.V. All rights reserved.
LUXEON Neo 0.5mm2
Assembly and Handling Information
Introduction
This application brief addresses the recommended assembly and handling
procedures for LUXEON Neo emitters. LUXEON Neo emitters are designed to deliver
high luminous ux and ecacy in automotive exterior lighting applications. Due to the
small size and construction, they require special assembly and handling precautions.
Proper assembly, handling and thermal management, as outlined in this application
brief, ensures high optical output, long term lumen maintenance and high reliability
of LUXEON Neo emitters in automotive applications.
Scope
The assembly and handling guidelines in this application brief apply to LUXEON Neo
0.5mm2products.
Any assembly or handling requirements that are specic to a subset of LUXEON Neo
products is clearly marked. In the remainder of this document, the term LUXEON
Neo refers to any product in the LUXEON Neo product family.

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 2
Table of Contents
Introduction ...........................................................................1
Scope.................................................................................1
1. Component ........................................................................3
1.1 Reference Document .................................................................3
1.2 Description ..........................................................................3
1.3 Form Factor .........................................................................4
1.4 Optical Center .......................................................................4
1.5 Polarity Marking......................................................................5
1.6 Side Coat Geometry ..................................................................5
1.7 Mechanical Files......................................................................6
2. Handling Precautions ................................................................6
2.1 Electrostatic Discharge Protection (ESD).................................................6
2.2 Component Handling .................................................................6
2.3 Cleaning ............................................................................8
3. Printed Circuit Board ................................................................8
3.1 PCB Requirements ...................................................................8
3.2 Footprint and Land Pattern............................................................8
3.3 Board Fiducial for Solder Mask Dened Footprint ........................................9
3.4 Array Conguration..................................................................10
3.5 Surface Finishing ....................................................................10
3.6 Solder Mask ........................................................................10
3.7 Silk Screen or Ink Printing ............................................................10
3.8 PCB Quality and Supplier.............................................................10
4. Thermal Management ..............................................................11
4.1 Thermal Resistance..................................................................11
4.2 Close-Proximity Thermal Performance .................................................13
4.3 Thermal Measurement Instructions ...................................................13
5. Assembly Process Recommendations and Parameters ..................................15
5.1 Solder Paste ........................................................................15
5.2 Stencil Design.......................................................................15
5.3 Stencil Printing......................................................................16
5.4 Pick and Place Nozzle ................................................................17
5.5 Placement Force/Height Control ......................................................18
5.6 Feed System........................................................................19
5.7 Vision Recognition...................................................................19
5.8 Placement Accuracy .................................................................20
5.9 Reow Prole .......................................................................20
5.10 Void Inspection ....................................................................21
5.11 Reow Accuracy ...................................................................22
5.12 Electrical Polarity Testing ............................................................23
5.13 Board Handling and Bending ........................................................23
5.14 Packing of Assembled LUXEON Neo Module...........................................24
6. Interconnect Reliability..............................................................24
7. JEDEC Moisture Sensitivity Level......................................................25
8. Packaging Considerations—Chemical Compatibility .....................................26

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 3
1. Component
1.1 Reference Document
The LUXEON Neo datasheet, DS172, is available upon request. Please contact your Lumileds sales representative.
1.2 Description
The LUXEON Neo emitter consists of a single LED chip combined with a phosphor converter to emit white light. It does not
contain any additional carrier substrate and electrical contacts are located directly underneath the die level. The outside of
the package is coated with white silicone to shield the chip from the environment and to prevent light leakage to the sides
(top emitter). The LUXEON Neo emitter includes an embedded transient voltage suppressor structure in the active layers
of the LED (eTVS) to protect the emitter against electrostatic discharges (ESD), see Figure 1.
Figure 1. Top view (left) and bottom view (right) of the LUXEON Neo emitter.
Table 1. Design features of LUXEON Neo.
PRODUCT PHOTO DESCRIPTION
LUXEON Neo 0.5mm2
Part number: A1N1-58500BH0xxxxx
Nominal drive current: 500mA
Die size: 0.5mm2
Light emitting area: 0.76mm x 0.76mm
Package size: 1.13mm x 1.13mm

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 4
1.3 Form Factor
The dimensional design for LUXEON Neo 0.5mm2 is outlined below in Figure 2. See the latest LUXEON Neo datasheet for
applicable tolerances.
Figure 2. Dimensions in millimeters for LUXEON Neo 0.5mm2.
1.4 Optical Center
The LUXEON Neo has no lens (primary optics). The optical center is at the center of the Lumiramic™ as indicated by the
red dot, and the solder pad center is indicated by the green dot, both shown in Figure 3 below. The optical center to solder
pad center tolerance is ±25µm (see datasheet for latest information on tolerances). Optical rayset data of each LUXEON
Neo part is available upon request.
Figure 3. Theoretical optical center and solder pad center for LUXEON Neo 0.5mm2.

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 5
1.5 Polarity Marking
The polarity of LUXEON Neo is marked on the top side with a black dot on the side where the anode pad is located
(Top view image in Figure 4). This marking can be used during assembly setup for manual polarity verication. On the
bottom anode side there is an alphanumeric OCR code (Bottom view image in Figure 4), which can be used to identify the
production batch and full test parameter traceability. This marking can also be used during pick and place assembly for
polarity check (see Chapter 5.7, “Vision recognition” for details).
Figure 4. Top side polarity mark (left) and bottom side OCR mark (right) for LUXEON Neo 0.5mm2.
1.6 Side Coat Geometry
The white side coat rim is designed to be lower than the light emitting surface (phosphor). Single particles protruding out
of the side coat material may occur. At these positions, the material can be a maximum of 25µm higher than the light
emitting surface at the hatched area (see Figure 5).
Figure 5. Side coat for LUXEON Neo 0.5mm2.
The side coat represents the package outline. The center of this geometry may have an oset to the pad center and should
not be used for referencing, shown in Figure 6 below (see latest datasheet for applicable tolerances).
Figure 6. Oset between pad center and outline center.

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 6
1.7 Mechanical Files
Mechanical drawings for LUXEON Neo (2D and 3D) are available upon request. For details, please contact your Lumileds
sales representative.
2. Handling Precautions
Like all electrical components, there are handling precautions that need to be taken into account when setting up
assembly procedures. These LUXEON Neo precautions are noted here in section 2.
2.1 Electrostatic Discharge Protection (ESD)
Electrostatic discharges, rapid transfers of charges between two bodies due to an electrical potential dierence between
those bodies, can cause unseen damage to electronic components. In LED devices, ESD events can result in a slow
degradation of light output and/or early catastrophic failures. In order to prevent ESDs from causing any damage, Lumileds
devices include a protection diode which is parallel to the chip and in reverse direction. This embedded diode (eTVS)
provides a current path for negative transient voltage (see Figure 7). Current through this eTVS structure will generate light,
as well, and should not be used for normal operation. This implies that polarity check for LUXEON Neo emitters should not
be done by testing light output under low current probing.
Figure 7. Electrical schematic of LUXEON Neo 0.5mm2.
Common causes of ESD include the direct transfer of charges from the human body or from a charged conductive object
to the LED component. In order to test the susceptibility of LEDs to these common causes of ESDs, three dierent models
are typically used:
• Human Body Model (HBM)
• Machine Model (MM)
• Charged Device Modell (CDM)
LUXEON Neo emitters have been independently veried to successfully pass ESD tests under HBM, MM and CDM
conditions. For the respective test voltages of these tests please refer to the latest LUXEON Neo Datasheet. Nevertheless,
Lumileds strongly recommends that customers adopt handling precautions for LEDs similar to those which are commonly
used for other electronic surface mount components which are susceptible to ESD events. Additional external ESD
protection for the LED may be needed if the LED is used in non ESD-protected environments and/or exposed to higher
ESD voltages and discharge energies, e.g. as described in ISO 10605 or IEC 61000-4-2 (severity level IV). For details please
contact your Lumileds sales representative.
2.2 Component Handling
Minimize all mechanical forces exerted onto the silicone package of LUXEON Neo. The white package consists of fragile
silicone material and should not be handled with tweezers that can lead to damage of the package, especially not with
metallic tweezers. Any force above 0.5 N may damage the silicone side coat and change optical performance. A vacuum
pen can be used instead of tweezers (see Figure 8).
The suction tip should be made of a soft material such as rubber to minimize the mechanical force exerted onto the
top surface of the LED and apply no forces to the silicone side coat layer. Avoid contaminating the top side surface of

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 7
the LED with the soft material. Do not stick any tape on top of the light emitting surface, such as capton- or UV-tape. A
contamination of glue or its invisible constituent parts may change the LED performance.
Electrical testing before assembly should be avoided. Probe tips may scratch or dent the pad surface and damage active
layers below. Avoid contact with the LED other than what is required for placement. Lumileds stongly recommends
handling with automatic assembly equipment only where forces to the component can be well controlled.
Figure 8. LED handling.
Do not touch the top surface with ngers or apply any pressure to it when handling nished boards containing LUXEON
Neo emitters. Do not stack nished boards because the LED can be damaged by the other board outlines. In addition, do
not put nished boards with LUXEON Neo emitters top side down on any surface. The surface of a workstation may be
rough or contaminated and may damage the LED.
Figure 9. Board handling.
Mishandling will lead to damages of side coat material shown in Figure 10 below (see Chapter 5.14 “Packing of assembled
LUXEON Neo Module” for proper handling of nished products).
Figure 10. Damaged LUXEON Neo emitter.

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 8
2.3 Cleaning
The surface of the LUXEON Neo emitter should not be exposed to dust and debris. Excessive dust and debris on the LED
chip array may cause a decrease in light output and optical behaviour. It is best to keep LUXEON Neo emitters in their
original shipping reel until actual use.
In the event that the surface requires cleaning, a compressed gas duster or an air gun with 1.4bar (at the nozzle tip), a
distance of 15cm will be sucient to remove the dust and debris. Make sure the parts are secured rst, taking above
handling precautions into account.
One can also rinse with isopropyl alcohol (IPA). Do not use solvents that are listed in Table 9, as they may adversely
react with the LED assembly. Extra care should be taken not to destroy the white silicone coating around the LED chips.
Lumileds does not recommend ultrasonic supported cleaning for LUXEON Neo emitters.
3. Printed Circuit Board
3.1 PCB Requirements
The LUXEON Neo can be mounted on multi-layer FR4 Printed Circuit Boards (PCB) or Insulated Metal Substrates (IMS).
To ensure optimal operation of the LUXEON Neo emitters, the thermal path between the LED package and the heatsink
should be optimized according to the application requirements. Please ensure that the PCB assembly complies to the
applicable IPC standards listed below.
General PCB Standards:
• IPC A-600H: Acceptability of Printed Boards
• IPC A-610F: Acceptability of Electronic Assemblies
• IPC 2221A: General Standard on Printed Board Design
• IPC 7093: Design and Assembly Process Implementation for Bottom Termination Components
Filled and Capped Via Boards:
• IPC 4761: Design Guide for Protection of Printed Board Via Structures
• IPC 2315: Design Guide for High Density Interconnects and Micro Vias
• IPC 2226: Design Standard for High Density Interconnect Printed Boards
3.2 Footprint and Land Pattern
Lumileds recommends using solder mask dened land pattern for LUXEON Neo, shown in Figure 11. Due to this, the
copper area can be extended as far as possible for better heat spreading, which results in lower thermal resistance.
However, a solder mask dened pad requires good mask quality and tight registration tolerances during PCB
manufacturing (see Chapter 3.8 “PCB Quality” for more details).
For the solder mask dened land pattern, the self-alignment of the component during reow soldering can be controlled
well by solder mask geometry in Y-direction. To compensate the solder mask registration tolerance, the X dimension is
slightly extended and the component can self-align in X-direction to the trench in the metal layer.

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 9
Figure 11. Solder mask dened land pattern for LUXEON Neo 0.5mm2.
For applications where requirements on thermal performance are less demanding, a lower solder mask quality may be
acceptable when using a metal dened pad geometry, shown in Figure 12. Self-alignment of the component during reow
is mainly dened by metal structure. The solder mask is retracted and serves to stop the solder wetting outside the LED
area and it may be removed if solder wetting can be limited by solder process.
Figure 12. Metal dened land pattern for LUXEON Neo 0.5mm2.
3.3 Board Fiducial for Solder Mask Dened Footprint
For the solder mask dened LUXEON Neo land pattern, an oset between metal and solder mask becomes critical during
solderpaste print and SMT assembly. The component aligns according to the soldermask in Y-direction and according to
metal in X-direction. In order to achieve best soldering accuracy, dedicated ducials for LEDs can be used, which represent
both layers shown in Figure 13. The shift of the shown ducial is dened by soldermask in Y-direction and by metal in
X-direction, identical to the shift of the LED. The ducial must be aligned in the same orientation as the LEDs. The vision
recognition in the SMT process must be programmed to detect the exposed metal square of 1mm x 1mm. A dark solder
mask color may be needed for proper contrast.
Figure 13. Solder mask and metal dened ducial.

AB172 LUXEON Neo 0.5mm2Application Brief 20180513 ©2018 Lumileds Holding B.V. All rights reserved. 10
3.4 Array Conguration
For applications that require low position tolerances between multiple LEDs, they should be oriented in the same direction.
Avoid 90 degree rotation within this array. Spacing of LEDs down to 0.2mm edge-to-edge for high density needs is feasible,
assuming capable processes. A spacing of 0.3mm or more is prefered to avoid mechanical contact.
3.5 Surface Finishing
Lumileds recommends using ENIG (Electroless Nickel Immersion Gold) plating according to IPC-4552. Other surface
nishes are possible but have not been tested by Lumileds. Surface nish Hot-Air-Solder-Leveling (HASL) may have
inhomogenious pad height and is not recommended for LUXEON Neo.
3.6 Solder Mask
A solder mask thickness of 21µm ±7µm on top of metal layer is desired. Mask and PCB vendors have to be evaluated for
proper quality. Systems with a photo lithographic structuring process are known to deliver better tolerances than screen
printed materials. Due to the small footprint of the LUXEON Neo emitters, this requirement is important in order to
achieve good assembly quality.
3.7 Silk Screen or Ink Printing
Silk screen markings within and around the LUXEON Neo outline should be avoided because the height of the ink may
interfere with the LUXEON Neo and solder stencil printing process. This can cause rotation, tilt and increased risk of solder
bridging (short circuit). If needed, the ink printing should be at least 2mm away from the LUXEON Neo outline.
3.8 PCB Quality and Supplier
Select only PCB suppliers that are capable of delivering the required level of quality. Leastwise, the PCBs must comply with
IPC standard IPC-A-600H, 2010 (“Acceptability of Printed Boards”).
A maximum mask registration tolerance of 50µm between the copper trace pattern and solder mask is desirable to
achieve optimum solder joint contact area using the recommended solder mask dened footprint as shown in Figure 14.
If the oset between the solder mask and the copper land pattern is large, one side of electrode pads will have less solder
joint contact area. This may aect package centering, tilting, and thermal performance and may increase risk of solder
bridging (short circuit) and solder balling if the stencil is not properly aligned to the solder mask during printing.
Figure 14 shows an example of the solder pad size for three dierent registration oset levels between the copper trace
pattern and the solder mask for LUXEON Neo 0.5mm² using the recommended footprint in Figure 11. Large misalignment
between solder mask opening and copper trace will cause one of the two copper land patterns to be smaller than the
other. Depending on the PCB manufacturer capability, PCB cost consideration and customer position tolerance needs, it
may be necessary to extend the area of the solder mask opening.
Figure 14. Solder mask registration oset to copper trace.