Application Note

Assembly Precautions
for the Nichia T02 Series LEDs
Table of contents
1. LED Outline Dimensions/Tape Dimensions ・ ・ ・ ・ ・ ・ ・ ・ ・ 2-3
2. Handling Precautions

・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 4

3. Design Recommendations for Optimal Amount of Solder・ ・ ・ ・ 5

4. Precautions for Setting Up a Pick-and-Place Machine/Nozzle ・ ・ 6-9
5. Precautions When Reflow Soldering

・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 9

6. Evaluation of the Effect of Solder Volume ・ ・ ・ ・ ・ ・ ・ ・ ・ 10-11
7. Evaluation of Self-Alignment Performance・ ・ ・ ・ ・ ・ ・ ・ ・ 12

8. Evaluation of the Solder Joint Shear Strength・ ・ ・ ・ ・ ・ ・ ・ 13

The part number NSSLT02A,NSSWT02A,NSSLT02A-V1,NSSWT02A-V1,NSSLT02A-V2,NSSWT02A-V2 in thisdocument are the part number of our product, and do not have any relevance or similarity to other companies'
products that may have trademark rights.
This document contains tentative information, Nichia may change the contents without notice.

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1. LED Outline Dimensions/Tape Dimensions（A, A-V1）
Table 1. Product Specifications

Part Number

NSSLT02A, NSSWT02A, NSSLT02A-V1, NSSWT02A-V1
Anode

0.7

0.55

Cathode

0.15

0.75

LED

4±0.1

0.2±0.05

1.35±0.1

3.5±0.05

Embossed
Carrier
Tape

Cathode

2

±0.05

8±0.1

4±0.1

Φ1.5+0.1-01.75±0.1[unit: mm, Tolerance: ±0.1mm]

0.85±0.1
Φ0.5 ±0.05

0.8 ±0.1

Reel Size: 4,000 LEDs
[unit: mm]

This document contains tentative information, Nichia may change the contents without notice.

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1. LED Outline Dimensions/Tape Dimensions（A-V2）
Table 2. Product Specifications

Specific feature for this seriesPart Number

NSSLT02A-V2, NSSWT02A-V2
Anode

0.7

0.55

Cathode

0.15

0.75

LED

(0.02 クロスバー凹部)(0.02 Crossbar Recess)

4±0.1

0.2±0.05

1.35±0.1

Cathode Mark3.5±0.05

Embossed
Carrier
Tape

2

±0.05

8+0.1

4±0.1

Φ1.5+0.1-01.75±0.1[unit: mm, Tolerance: ±0.1mm]

0.9 ±0.1
Φ0.5 ±0.05

0.85±0.1

Reel Size: 4,000 LEDs
[unit: mm]

This document contains tentative information, Nichia may change the contents without notice.

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Assembly Precautions for the Nichia T02 Series LEDs

2. Handling Precautions

Incorrect
Caution: Do not grab/hold the LEDs
with tweezers around theencapsulating resin.

Handling with bare hands
Ensure that when handling the LEDs with tweezers, excessive force is not applied to the LED. Otherwise, it
may cause damage to the resin (e.g. cut, scratch, chip, crack, delamination and deformation) and theinternal connection to fail causing a catastrophic failure (i.e. the LED not to illuminate).
Handling with tweezers
Ensure that when handling the LEDs with tweezers, excessive force is not applied to the LED. Otherwise, it
may cause damage to the resin (e.g. cut, scratch, chip, crack, delamination and deformation) and theinternal connection to fail causing a catastrophic failure (i.e. the LED not to illuminate).
ESD Precautions
LEDs are sensitive to transient excessive voltages (e.g. ESD, lightning surge). If this excessive voltage
occurs in the circuit, it may cause the LED to be damaged causing issues (e.g. the LED to have a
reduction in the radiant flux or not to illuminate [i.e. catastrophic failure]). When handling the LEDs,
ensure that necessary measures have been taken to protect them from transient excess voltages. Referto the applicable specification for more details.

Figure 1. Example of an improper
holding position

Incorrect

Stacking assembled PCBs together
Do not stack assembled PCBs together. Otherwise, it may cause damage to the resin (e.g. cut, scratch,chip, crack, delamination and deformation) and the internal connection to fail causing a catastrophic
failure (i.e. the LED not to illuminate).

Caution: Do not stack assembled
PCBs on top of each other.

Storage
The storage/packaging requirements for this LED are comparable to JEDEC Moisture Sensitivity Level(MSL) 2a or equivalent. Nichia used IPC/JEDEC STD-020 as a reference to rate the MSL of this LED.
Note: Since baking is not guaranteed for the Nichia T02 Series LEDs, once the moisture-proof aluminumbag is opened ensure that soldering is completed within the storage times detailed in the applicablespecification.

Figure 2. Example of improper stacking

Table 3. Storage conditions
Conditions
Storage

Temperature

HumidityTime

Before Opening Aluminum Bag≤ 30°C≤ 90% RH

Within 1 Year from Delivery Date

After Opening Aluminum Bag≤ 30°C≤ 70% RH

≤ 4 weeksThis document contains tentative information, Nichia may change the contents without notice.

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Assembly Precautions for the Nichia T02 Series LEDs

3. Design Recommendations for Optimal Amount of Solder
Soldering Pad Pattern/Metal Solder Stencil Aperture

Table 4. Recommended Soldering Pad Pattern/Metal Solder Stencil Aperture

Recommended Soldering Pad Pattern

Recommended Metal Solder Stencil Aperture[Unit: mm][Unit: mm]⋯: LED outline (outer), Electrodes (internal)■: Soldering Pad Pattern■: Metal Solder Stencil Aperture

Table 5. Recommended Solder/Metal Solder Stencil Conditions

Item

Recommended Conditions

Metal Solder Stencil (Thickness)

150 μmSolder Paste (Composition)

Sn-3.0Ag-0.5Cu
This document contains tentative information, Nichia may change the contents without notice.

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4. Precautions for Setting Up a Pick-and-Place Machine/Nozzle
Table 6. Cautions/Suggestions for setting up equipment

Item

Recommended
Conditions/Specifications

Cautions/Suggestions

Pick-and-place machine1

Modular mounter

Pick-and-place nozzle

Nozzles for 0402 (1005 metric) to 0603 (1608
metric) package components

See “Pick-and-Place Nozzle” onpage 7 for the details.

Tape-and-reel feeder

Electrical (motorized) feeder
Tape width: 8mm
Feed length: 4mm

See “Tape-and-Reel Feeder” onpage 7 for the details.

Nozzle height for pick-up
operations

The contact surface of the nozzle head for pick
operations should be adjusted to the same heightas the edge of the embossed carrier tape pocket.

See “Recommended Nozzle
Height for Pick-up Operations”
on page 8 for the details.

0.2mm for placement depth

See “Recommended Nozzle
Height for Placement
Operations (Placement Depth)” on page 8 for the details.

Nozzle height for placement
operations (i.e. placement
depth)

Note:
1 The recommended conditions/specifications above have been determined under the following verification conditions:
Pick-and-place machine (modular mounter):- YS100 High-Speed General-Purpose Modular (manufactured by Yamaha Motor Co., Ltd.)- BM231 NE-EJM1C Modular Placement Machine (manufactured by Panasonic Smart Factory Solutions Co., Ltd.)This document contains tentative information, Nichia may change the contents without notice.

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Assembly Precautions for the Nichia T02 Series LEDs
4-1. Pick-and-Place Nozzle• Ensure that an appropriate nozzle is used for the LEDs.
Note: For reference purposes, Figure 3 (left) provides theoutline dimensions of the nozzles used for theverification (See Table 6 Note).

1.0

0.8

• Pick-and-place nozzles for 0402 (1005 metric) to 0603
(1608 metric) package components may be appropriate
for the LEDs. However, since it may vary depending on
the pick-and-place machine, sufficient verification shouldbe performed to ensure there are no issues with thenozzle being used.

[Unit: mm]• The placement force applied by the nozzle on the LEDs
must be ≤ 3.5N.

Figure 3. Reference Nozzle Dimensions

4-2. Tape-and-Reel Feeder• Recommended setting for the tape-and-reel feeder.

Recommended Tape
Removal Position

Tape width: 8mm
Feed length: 4mm• Use a tape-and-reel feeder that ensures it does not create
excessive vibrations causing assembly issues.

Correct

LED pick up position

Example: Electrical (motorized) feeder• If LEDs in the embossed carrier tape pockets are not in thecorrect position when picked by the nozzle, reduce thefeed speed.

Incorrect

LED pick up position

Figure 4. Examples of Correct/Incorrect Top Cover Tape Removal Positions• When removing the top cover tape, it should be done at apoint sufficiently far away from the target LED (See Figure
4 for the details). Otherwise, it can shake the embossed
carrier tape and cause the LED to move within the tapepocket or outside of the tape pocket.
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Assembly Precautions for the Nichia T02 Series LEDs
• Adjust the pick-and-place nozzle to ensure that the contact
surface is positioned at the same height as the edge of the pocket
to pick up the LED (i.e. recommended nozzle height for pick-up
operations).

4-3. Recommended Nozzle Height for
Pick-up Operations
Pick-and-Place Nozzle• The recommended nozzle height for pick-up operations has been
determined by Nichia under the verification conditions (See Table
5 Note) and may not function as expected with some other pickand-place machines. If the pick-up operations are unstable evenwith using the recommended nozzle height, adjust the nozzle
height appropriate for the pick-and-place machine being used.

It is recommended
that when picking up
the LEDs, the contact
surface of the nozzle
head is as high as
the edge of the tapepocket.

If the pick point of the nozzle is too high,- it may cause insufficient suction power leading to picking
errors (e.g. the nozzle’s failure to pick/lift the LED into theair, incorrect picking causing the LED to tilt when in the air).

Embossed Carrier
Tape (Pocket)

Figure 5. Recommended Nozzle Height for Pick-up Operations

4-4. Recommended Nozzle Height for Placement
Operations (Placement Depth)

If the pick point of the nozzle is too low,
- it may cause issues (e.g. causing the embossed carrier tape
to shake, causing the tape pocket to deform) leading topicking failures.

Pick-and-Place Nozzle• Adjust the nozzle height to ensure that the nozzle applies anadditional force (i.e. placement depth of 0.2mm) to the LED after
the LED has come in contact with the PCB.

Placement Depth
0.2mm

If the release point of the nozzle is too high,- it may cause placement issues (e.g. LED’s sticking to thenozzle after placement) or cause the LED to delaminate
from the PCB after reflow soldering.
If the release point of the nozzle is too low,
- excessive forces may be applied to the LED during
placement and it may cause the LED to break.

PCB
Figure 6. Recommended Nozzle Height for Placement (Placement Depth)

This document contains tentative information, Nichia may change the contents without notice.

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Assembly Precautions for the Nichia T02 Series LEDs
4-5. Imaging-based Automatic Inspection
Figure 7. Example ofautomatic position
recognition from an image:the machine extracts
information from theimage and adjusts thenozzle position to accountfor the positional deviationof the LED being picked.

5. Precautions When Reflow
Soldering• For accurate placement of the LEDs, use an automatic imagingbased recognition technology to correct misalignments.

• Reflow soldering must not be performed more than twice.
• Using the recommended reflow soldering conditions (See Figure 8
to the left) as a reference, modify if necessary, the recommended
reflow conditions specified by the manufacturer of the solder
paste being used.
Note:
To ensure that these reflow conditions have no negative effect on
the LEDs, perform sufficient verification prior to use.
• When cooling the LEDs from the peak temperature a gradualcooling slope is recommended; do not cool the LEDs rapidly.

Figure 8. Recommended Reflow Soldering Condition(Lead-free Solder)• During reflow soldering, the heat and atmosphere in the reflow
oven may cause the optical characteristics to degrade. In
particular, reflow soldering performed with an air atmosphere may
have a greater negative effect on the optical characteristics than if
a nitrogen atmosphere is used; Nichia recommends using anitrogen reflow atmosphere.
This document contains tentative information, Nichia may change the contents without notice.

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6. Evaluation of the Effect of Solder Volume
6-1. Evaluation Method/Conditions
The effect of solder volume on the workmanship of the reflow-soldered LEDs (e.g. LED emission failure,
number of solder balls) was evaluated using nine different evaluation configurations (i.e. three aperture
ratios, three stencil thicknesses) to control the amount of solder paste.
PCB2 specifications:Single-sided CEM-3
PCB thickness: 1.0mm
Copper layer thickness: 35μm
Metal Solder Stencil Thicknesses:
120μm, 150μm, 180μm

Metal Solder Stencil Aperture Patterns:

Aperture ratio3: 100%

(Nichia’s recommendation)

Aperture ratio3: 70%

Aperture ratio3: 40%■: Metal solder stencil aperture pattern▨ : LED electrodes

6-2. Evaluation Results
There were no assembly-related issues (e.g. emission failure, solder ball) with the evaluation conditions(i.e. volume of the solder paste) used. For more details, refer to Tables 7, 8 and 9 on the next page.

Note:
2 Nichia’s recommended soldering pad pattern was used.
3 Aperture ratio [%]: Area of the solder directly beneath the electrodes / area of the electrodes
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6-2. Evaluation Results (continued)
Table 7. Stencil Thickness: 120μm Evaluation Result
Aperture Ratio

Top

Side A

Table 8. Stencil Thickness: 150μm Evaluation Result
Side B

Aperture Ratio

100%

100%

70%

70%

40%

40%

Top

Side ASide B

Table 9. Stencil Thickness: 180μm Evaluation Result
Aperture Ratio

Top

Side ASide B

Anode

100%

Observing Direction(Side B)
Cathode70%

Observing Direction (Side A)

40%

Figure 9. Observation Direction
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7. Evaluation of Self-Alignment Performance
7-1. Evaluation Method/Conditions
The self-alignment performance of the LEDs was evaluated using the following evaluation method/conditions:
PCB3 specifications:Single-sided CEM-3
PCB thickness: 1.0mm
Copper layer thickness: 35μm

Metal Solder Stencil specifications:
Stencil thickness: 150μm (Nichia’s recommendation)
Aperture pattern:See Table 3 or the applicable specification(Nichia’s recommended metal solder stencil aperture)

7-2. Evaluation Results
The LEDs with the deviations above moved to the correct position (i.e. the center of the soldering pad pattern) bythemselves during reflow soldering (i.e. surface tension-driven self-alignment) and no issues (e.g. causing the LED not
to illuminate) were observed. For more details, refer to Table 10 below.
Table 10. Results of evaluating the self-aligning performance
Deviation from the soldering pad pattern center
Correct Position

x Direction+0.2mmｙDirection+0.2mmx,y Direction+0.2mmθ Direction+30°

θ Direction+45°

Appearance
beforereflow
solderingAppearance
after reflow
solderingThis document contains tentative information, Nichia may change the contents without notice.

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8. Evaluation of the Solder Joint Shear Strength8-1. Evaluation Method/Conditions
The shear force was applied to the side of the LED using a test jig and the shear strength was measured.
PCB3 specifications:Single-sided CEM-3
PCB thickness: 1.0mm
Copper layer thickness: 35μm

Metal Solder Stencil specifications:
Stencil thickness: 150μm (Nichia’s recommendation)
Aperture pattern:See Table 3 or the applicable specification(Nichia’s recommended metal solder stencil aperture)

8-2. Evaluation Results
The solder joint strength was sufficient due to the following reasons:- All the tested LEDs had damaged packages (See Figure 11 below)- No delamination was observed at the interface between the solder and PCB (i.e. soldering pad)
Shear Force Direction
Test Jig
試験冶具

Figure 10. How the Shear Force was Applied

Electrode delaminationfrom the LED withdamage to the
package

Figure 11. LED Appearance After the Test
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Disclaimer
This application note is a controlled document of Nichia Corporation (Nichia) published to provide technical information/data forreference purposes only. By using this application note, the user agrees to the following:• This application note has been prepared solely for reference on the subject matters incorporated within it and Nichia makes noguarantee that customers will see the same results for their chosen application.
• The information/data contained herein are only typical examples of performances and/or applications for the product. Nichia
does not provide any guarantees or grant any license under or immunity from any intellectual property rights or other rights
held by Nichia or third parties.
• Nichia makes no representation or warranty, express or implied, as to the accuracy, completeness or usefulness of any
information contained herein. In addition, Nichia shall not be liable for any damages or losses arising out of exploiting, using,or downloading or otherwise this document, or any other acts associated with this document.
• The content of this application note may be changed without any prior or subsequent notice.
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works hereof, is strictly prohibited.

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http://www.nichia.co.jp

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