Handling and Assembly Instructions
For SGPxx Gas Sensors
Preface
Sensirion SGPxx are gas sensors of high quality and aredesigned for high volume applications. They are therefore
compatible with standard assembly and soldering
processes. For taking advantage of their outstanding
performance, some precautions must be taken duringstorage, assembly, and packaging. Therefore, please readthe following instructions carefully – preferably during
design-in phase and prior to production release of therespective device. Proper handling and choice of materials
are crucial. Operating and storing sensors in the field underambient environment is not critical.

1environment is not critical, pollutants are known to occur in
manufacturing environments, by outgassing fromcontaminating materials, and/or during storage. Pleasecarefully follow the guidelines in these instructions to ensurethat you can benefit from the outstanding performance of
the SGPxx gas sensors.

Applicability

This document is applicable to all Sensirion SGPxx gassensors.

2ESD Protection

The sensor shall be protected from ESD (ElectrostaticDischarge) and only be handled in ESD protected areas(EPA) under protected and controlled conditions (ground all
personnel with wrist-straps, ground all non-insulating andconductive objects, exclude insulating materials from theEPA, operate only in grounded conductive floor, etc.).
Protect sensors outside the EPA using ESD protective
packaging.

The sensors shall not get in close contact with pure volatile
chemicals such as solvents or other organic compounds.
Especially high gas concentrations and long exposure tothem during storage must be avoided. Volatile organic
compounds cover classes such as ketones (e.g., acetone),aldehydes (e.g., formaldehyde), alcohols (e.g., ethanol),aromatics (e.g., toluene), esters (e.g., glycol ester), etc.
Please note that such chemicals are integral part of many
epoxies, glues, adhesives, etc. and they may outgas during
baking and curing. These chemicals are also added asplasticisers into plastics, used for packaging materials, anddo outgas for some period.

Figure 1

3Acids and bases may affect the sensor irreversibly and shallbe avoided: HCl, H2SO4, HNO3, NH3, acetic acid, etc. Also
oxidizing gases such as ozone (O3), nitrogen dioxide (NO2),and H2O2 in high concentration should be avoided. Organic
nitrogen compounds such as amines (e.g.,ethylenediamine, formamide, etc.) in the presence ofhumidity can irreversibly contaminate SGPxx sensors.
Such substances can outgas from materials used for PCB
and device design, for instance, conformal coatings,
plastics, and rubber sealings. Please note that theexamples listed above do not represent a complete list ofharmful substances.

Protection against ESD is mandatory.

Exposure to Chemicals
Ensure good ventilation and fresh air
supply to avoid accumulation of anychemicals.

SGPxx are highly sensitive environmental sensors and assuch they are not ordinary electronic components. Openingof the original package exposes the sensors to the given
environmental conditions and makes them susceptible topollutants. While applying sensors in the field in ambient

www.sensirion.com

Be particularly careful when using strong cleaning agents(e.g., detergents, alcohols, brominated or fluorinatedsolvents). Cleaning any part of a product might lead to highconcentration of cleaning agents on the sensor resulting inpermanent drift or complete breakdown of the sensor.
Please remove any sensors or devices containing sensors
before cleaning the production area and tools. Ensure goodventilation (fresh air supply) during production and after
cleaning with cleaning agents.

Version 1.2 – November 2020

1/7

4

Packing and Storage

5

Avoid mechanical contact during
pick-and-place process at the sensor
center.

Always store SGPxx gas sensors inoriginally sealed ESD bags andpreferably under dry conditions until
final use.
SGPxx gas sensors need to be stored with care. To avoid
accumulation of harmful gases that might settle on thesensing layers, it is recommended that the manufacturing
environment is well ventilated. Prior to assembly or use of
the sensors it is strongly recommended to store the sensors
in the original sealed ESD bag.
Once the sensors have been removed from the original
ESD bag we recommend to store the individual sensors aswell as devices with assembled sensors in sealed metal-inantistatic shielded ESD bags, preferably under vacuum, inan environment of inert gas (like N2) or synthetic air meeting
the requirements for temperature and relative humidity as
detailed under Recommended Operating and Storage
Conditions in the corresponding datasheet of the SGPxx
product. If the presence of contaminating gases (see 3Epxosure to Chemicals) cannot be excluded it is strongly
recommended to store the sensor under dry conditions(e.g., in a dry cabinet or by adding a silica gel pack to theclosed ESD bag). In particular, it is recommended not to use
any adhesive or adhesive tapes to reseal the sensor bag
after opening. Recommended ESD bags (no polluting effecton SGPxx sensors) are given in the table below.
ESD bag
Manufacturer
Stroebel

Pick-and-Place ProcessStandard pick-and-place equipment for QFN packages may
be used for handling. The center part of the sensor is very
sensitive to any mechanical impact and any contact must
be prevented. The inner diameter of the pick-and-placenozzle must be sufficiently large to ensure (underconsideration of maximum pick-up offsets) that the nozzle
will not be in mechanical contact with the central part of thesensor package with a diameter of 1.5 mm. In particular werecommend a pick-and-place nozzle having an opening
with inner diameter larger than 2 mm.

Figure 2 Areas of the sensor suitable for application of force
during mounting process. Force must only be applied outside thered area.

The surface of the tool that touches the module outside of
the center area should be flat and smooth. Pick-and-place
forces should not exceed 4 N during downward placement.

Product«topdry EMI» bags

Sensors as components or mounted into the final productshall not be packaged in outgassing plastic materials which
could cause sensor pollution. Besides metal-in antistatic
shielded ESD bags, paper or cardboards based packaging,deep drawn plastic trays (PE, PET, PP) may be considered.
Do not use antistatic polyethylene bags (light blue, pink orrose color); be very careful with bubble foils and foams.

6Water & Dust Protection Membrane
Water and dust protection membranemust not be removed, damaged oraltered in any way.

Be careful with stickers located inside the packing (e.g., on
the housing of the device). Sticker size should be kept to aminimum, and the sticky side shall fully adhere onto asurface.
Please note that many packaging materials may beprovided with additives (plasticizers) which may have apolluting effect on the sensor. Generally speaking, if amaterial emits a strong odor you should not use it. Suchadditives may also be added to materials which are listed
for recommended use herein. For high safety, Sensirion
recommends to qualify device housing and shipment
packaging in simulated shipping test.

www.sensirion.com

Figure 3 The dust protection membrane completely covers theSGPxx sensor surface.

The SGPxx gas sensor is equipped with a water and dust
protection membrane that is directly attached to the sensor.
The membrane completely covers the sensor opening (seeVersion 1.2 – November 2020

2/7

Figure 3) and thus acts as a shield against pollution fromspray water and dust. The membrane is completely
permeable to all target gases the SGPxx is intended tomeasure. Therefore, the water and dust protection
membrane must not be removed, damaged, or altered inany way to ensure reliable operation of the SGPxx gassensor.

7AssemblyNo mechanical force shall be applied to any part of thesensor during assembly or usage. Use gloves or finger cots
while assembling the SGPxx.

7.1 Soldering Instructions
Follow the recommended standard
soldering procedure during assembly.
Sensors in SMT packages such as Sensirion SGPxx gas
sensors are classified as Moisture Sensitivity Level 1(IPC/JEDEC J-STD-020). It is recommended to process thesensors within 1 year after date of delivery.
Standard reflow soldering ovens may be used for soldering.
The sensors are designed to withstand a soldering profile
according to IPC/JEDEC J-STD-020 with a recommended
peak temperature of 245 °C during up to 30 s for Pb-free
assembly in IR/Convection reflow ovens (see Figure 4). In
addition, we strongly advice a maximum ramp-down rate of<4 °C/s. Make sure that maximum temperatures andexposure times are respected. In case the PCB passes
through multiple solder cycles (as is the case for, e.g., PCBs
that are assembled on top and bottom side), it isrecommended to assemble the SGPxx only during the lastsolder cycle. This is to reduce risks of sensor pollution.

and any part of the substrate) of 50–75 μm. Please consult
the appropriate sensor data sheet for device specificinformation on metal land patterns and recommendations
on solder paste printing stencils.
Recommended conditions during soldering
Phase
Temperature Ramp
Liquid phase
TL < 220 °C –Ramp-up–<3 °C/sPeak
TP = 245 °C –Ramp-down–<4 °C/sTime
tL < 150 s–
tP ≤ 30 s–

Board wash shall be avoided for Sensirion SGPxx gassensors and it is therefore recommended to use a “noclean” solder paste. In addition, we recommend not to use
ultrasonic cleaning since it could result in damage of thesensor. If a board wash is a requirement for the final productor application, the corresponding wash process needs to beproperly qualified in order to prove compatibility with theSGPxx gas sensor.

Figure 5sensors.

Do not apply board wash to PCBs containing SGPxx

We recommend not to manually solder the Sensirion
SGPxx gas sensor since corresponding processparameters may not be controlled well and it could result ina damage of the sensor. In particular, hot air with an air
temperature above 250 °C on the device surface should beavoided. Since the sensing element has a very low thermalmass, it heats up to the air temperature very quickly.
It is important to note that the side faces of the I/O pads may
oxidise over time. Therefore, a solder fillet may or may notform.

Figure 4 Soldering profile according to JEDEC standard.
Recommended parameters are detailed in the table below.

It is recommended not to use vapour phase soldering toavoid potential contamination of the sensor. The use of “noclean” type 3 solder paste is recommended. 1 An
appropriate amount of solder paste shall be used to achievea stand-off height (clearance between the package body

For application in corrosive environment – such ascondensed water or corrosive gases – it may be necessary
to protect the electronic assembly including the soldered
contacts of the sensor with a passivation. Such passivation
may be achieved by conformal coating or by applying
adhesive.

1 Solder types are related to the solder particle size in the paste: Type 3

covers the size range of 25–45 µm as specified in IPC J-STD-005A.

www.sensirion.com

Version 1.2 – November 2020

3/7

7.2 Conformal Coating
Low viscose conformal coatings or potting materials may
flow onto the sensor, cover the sensor element and thus
render the gas sensor dysfunctional. Ensure that nothing is(even partly) covering the dust protection membrane of thesensors. Do not protect/cover the top surface with tape as
this may harm the dust protection membrane.

85 °C. In any case, ensure good ventilation throughout theapplication, staging and curing to prevent sensor pollution.

Use recommended conformal
coatings, avoid outgassing by curing
and avoid covering of the sensor top
surface.
Make sure that the employed conformal coating material is
not outgassing volatile organic compounds (e.g., aromatics)
or organic nitrogen compounds (e.g., amines) that willoutgas in the final application in order not to compromise
the sensor reading.

Figure 6

Figure 7 If conformal coating is applied, the top surface of thesensor must remain free of coating.

In order to ensure a homogeneous baking it is essential tohave the thinnest possible coating and avoid accumulationof the fluid material in gaps and voids on the PCB.

Do not put tape directly on the sensor.

Do not use silicone-based conformal coatings. Sensirion
tested and recommends the conformal coatings listed in thetable below which are known to be suitable if applied andfully cured under good ventilation (fresh air supply) andaccording to respective datasheet.
Conformal coating
Manufacturer
ProductChase
Humiseal 1B73EPA
PetersElpeguard SL 1301 ECO-FLZ
Electrolube
AFA (Aromatic Free Acrylic ConformalCoating)

The SGPxx gas sensor is highly sensitive to small ambient
gas concentrations. Therefore, it has to be ensured that theconformal coating is not outgassing to avoid unwanted gas
concentrations around the sensor. Drying conformal
coatings for 24 h at room temperature and additional baking
for 5 h at 80 °C has been tested and leads to reduced
outgassing. Depending on the type and amount/thicknessof coating, longer baking time might yield even better
results. However, baking temperature should not exceed

www.sensirion.com

Figure 8

Do not spray onto sensor.

7.3 Adhesives and EncapsulantsUse recommended adhesive andencapsulant materials.
Regarding adhesives and encapsulants the materials in thefollowing tables have been tested and may be used –according to respective datasheets, applied and fully cured
in well ventilated environment (fresh air supply). Other
materials than the ones listed below might also be used,however they were not tested and thus are notrecommended.
Epoxy adhesives
Manufacturer
EPO-TEKProduct
H70S

The sensor shall be mounted into the final product, ifpossible, after all materials that are used in the assemblyprocess have completely cured, outgassed or dried out.

Version 1.2 – November 2020

4/7

Otherwise ensure good ventilation (fresh air supply) incuring ovens and assembly lines.

is placed in with kapton tape (specific recommendation seeabove).

Other recommended materials
Manufacturer
Product
TeflonPEEKPolycarbonate (PC)ABS
FR4 PCB
Viton seals (after thermal outgassing)
3M
Kapton (polyimide) tape
Polyethylene

8

7.4 Handling after Assembly until Final Use
Seal the device housing by arecommended adhesive afterassembly.
In order to protect the SGPxx gas sensor during shipment,
it is strongly recommended to seal the cavity of the housing
in the device where the sensor is placed in by one of therecommended adhesives (see above) until its final use by
the end-customer. The adhesive must not touch the dust
protection membrane of the SGPxx. It must be ensured thatthe cavity itself is not outgassing any polluting agents asdetailed in Section 3 Exposure to Chemicals and Section
8 Application in Extreme Environments.

Application in Extreme Environments

Some applications require the exposure of gas sensors toharsh environments. In many cases, this is uncritical for theuse of the SGPxx. However, some precautions must be
taken.
For exposure to extreme conditions with regards to humidity
and temperature please consult the datasheet of therespective product. Please make sure that exposure time ofthe sensor to the maximum range of operating conditions islimited. Limits are provided in the corresponding data sheet.
Exposure to volatile organic compounds at highconcentration and long exposure time is critical not only inassembly but also in the field. Such applications need to becarefully tested and qualified.
Exposure to acids (pH < 6) or bases (pH > 8) may be
critical, too. Critical concentrations are typicallyconcentrations high enough to attack polymers. Etching
substances such as H2O2, NH3, etc. at high concentration
are critical to the sensor, too. Exposure to organic nitrogencompounds such as amines can lead to irreversible drift ofthe sensor even at small concentrations in the ppm range
and must be thus avoided.
Corrosive substances at very low concentrations are notcritical to the sensor itself. However, they may attack thesolder contacts. Therefore, the contacts must be well
protected (passivated) in case of an application to suchenvironment – compare also Section 7 Assembly.
Application of Sensirion SGPxx sensors to harshenvironments must be carefully tested and qualified.
Sensirion qualifies its SGPxx sensors to work properly
within ambient clean air – qualification for use in harshenvironments is duty of the user of the sensor.

Figure 9 Cover the device cavity where the SGPxx is located bya recommended adhesive during shipment until final use as wellas during rework and repair.

7.5 Rework and Repair of Final Devices
Handling instructions also apply
during repair and rework ofassemblies.
Ensure that recommendations in these instructions areequally considered during repair and rework of assemblies
containing the SGPxx gas sensor. The replacement of
SGPxx gas sensors requires another reflow soldering step.
During repair and rework it may be recommendable to cover
the opening of the cavity within the device where the SGPxx

www.sensirion.com

9Disclaimer

The above given restrictions, recommendations, materials,
etc. do not cover all possible cases and items. Material
recommendations are provided regarding pollution of
SGPxx gas sensors and assume optimally sealed storage
conditions – the materials were not tested regarding otherproperties like reliability, performance, usability ormechanical properties. The material recommendations
have been compiled with our best knowledge at the time ofwriting. Manufacturers may change the compounds without
notice, which can lead to reduced sensor performance due
to outgassing. This document is not to be considered
complete and is subject to change without prior notice.

Version 1.2 – November 2020

5/7

Revision History
DateApril 2018
May 2020
November 2020

Version
1.0
1.1
1.2

Changes–Total revision
More detailed description of pollutants added to all sections.
Section 4: recommendations for packing and storage adapted.
Section 5: visualization of SGP4x added to Figure 2.
Section 6: visualization of SGP4x added to Figure 3.

www.sensirion.com

Version 1.2 – November 2020

6/7

Copyright © 2020 by SENSIRION
CMOSens® is a trademark of Sensirion
All rights reserved

Headquarters and Subsidiaries
Sensirion AG
Laubisruetistr. 50
CH-8712 Staefa ZH
Switzerland

Sensirion Inc., USA
phone: +1 312 690 5858
info-us@sensirion.com
www.sensirion.com

Sensirion Korea Co. Ltd.
phone: +82 31 337 7700~3
info-kr@sensirion.com
www.sensirion.com/kr

phone: +41 44 306 40 00
fax:+41 44 306 40 30
info@sensirion.com
www.sensirion.com

Sensirion Japan Co. Ltd.
phone: +81 3 3444 4940
info-jp@sensirion.com
www.sensirion.com/jp

Sensirion China Co. Ltd.
phone: +86 755 8252 1501
info-cn@sensirion.com
www.sensirion.com/cn

Sensirion Taiwan Co. Ltd
phone: +886 3 5506701
info@sensirion.com
www.sensirion.com

To find your local representative, please visit www.sensirion.com/distributors

www.sensirion.com

Version 1.2 – November 2020

7/7