APPLICATION NOTE
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Handling Procedures to Avoid Trapped Charges
AN54886/D
APPLICATION NOTE ABSTRACTThis application note provides guidelines on preventing
the generation of trapped charges.

 An electrostatic charge can be induced when cleaning

the device; therefore, if cleaning of the glass lid isnecessary, consider the following: Always wear ESD protective nitrile gloves(recommended NiProtect CC529) when handling image
sensors.
 If possible, remove particles on top of the glass byblowing with an ionized−N2 gun. If N2 is not available,
use an ionized clean dry−air gun. Ensure that theappropriate point of use filtering system is in place toprevent particle contamination from the ionizing gun.
 If the above procedure does not remove the particle, use
an ESD protective wipe (type S1091PRT from Puritech
or RTMKC002 from distributor Hans J. MichaelGMBH) to do a local cleaning with isopropyl alcohol(IPA), either extra pure or VLSI grade. Wet the wipewith the alcohol and then rub very gently over the glasslid.
CAUTION: Rubbing the glass, if not done properly, is
known to induce the creation of trapped charges. It is
important to use the correct ESD protective wipe.

INTRODUCTION
Image sensor products can be sensitive to electricalcharges transferred from external electrical fields and stored
in the pixel array (“trapped charge”). The trapped charge cancreate unwanted optical effects, which appear as random
dark spots in the image, typically several pixels in diameter.
Improper handling of the image sensor generates trappedcharges. Improper handling includes any operation thatcreates an electrostatic charge, for example, wiping thecover glass with non−ESD−protective wipes.
This application note discusses specific procedures tominimize creation of trapped charges. Refer to Application
Note AN52561, Image Sensor Handling Best Practices, forgeneral handling procedure recommendations.
Prevention of Trap Charge

Trapped charges can be avoided by proper handling of thesensor. onsemi ensures proper handling throughout themanufacturing, testing, and shipping processes, andmaintains testing procedures to ensure that image sensor
products do not exhibit trapped charges when shipped. It isequally important for the customer to implement proper
handling in receiving, testing, and board and systemmanufacturing operations at customer sites. The following
guidelines should be observed when handling image
sensors.
 Follow ESD protocols defined in JESD625−A. The
handling protocols must be periodically tested tovalidate their effectiveness.
 Handle image sensor devices while wearing a grounded
wrist strap and ESD protective gloves.
 Maintain a proper anti static environment where image
sensor devices are handled. This environment includes
grounded conductive surfaces and ionized air streams,
as determined by ESD auditing.
 Limit physical contact with the sensor cover glass. Suchcontact can induce an electro static charge. All contact
with the device must be done while wearing a grounded
wrist strap.
 Do not use any protective tape to cover the glass. The
application or removal of the tape can induce
electrostatic charge.

 Semiconductor Components Industries, LLC, 2012

December, 2023 − Rev. 3

Returns

onsemi will accept returns of image sensors with only if
the trapped charges are detected by the customer, duringincoming acceptance testing and the customer have usedproper handling procedures during acceptance testing. Afterthe devices are accepted by the customer, onsemi will not beresponsible for trapped charges in the devices.
 Unless otherwise agreed by customer and onsemi,customer has one month to complete acceptance testing
after the date of shipment. After one month, onsemi
will deem acceptance testing complete and the productunits accepted.
 If a trapped charge is detected during acceptance test,
notify onsemi according to the onsemi RMA
procedure. onsemi will arrange to evaluate the parts.
 onsemi reserves the right to audit customer−handlingprocedures during unpacking and acceptance testing toensure that these procedures are not causing the trappedcharges. If improper handling is identified as the cause,
onsemi will not accept return of the affected devices.
 onsemi will not be responsible for trapped charges
observed after completion of acceptance test by thecustomer.

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Publication Order Number:
AN54886/D

AN54886/D
 In the event that onsemi accepts return of devices

 Place the sensors in the oven for 24 hours at 150exhibiting trapped charges, onsemi reserves the right, atonsemi’ sole discretion and as customer’s sole andexclusive remedy, to refund the purchase price, orreplace or rework the affected devices.

degrees C.
 Let the units cool down for at least 2 hours.
 Place the sensors in the oven. Bake them at 150
degrees C for 2 hours. Bring them back to room
temperature for 30 minutes. Repeat this bake cycle 5times.
Alternately, if the units have already been mounted on aPCB, and if the components on the PCB cannot sustain
temperature higher than 70C; the trapped charge can bedispersed under bias at Ta = 70C for a duration of 2−3 days.
NOTE: Please place the PCB in the oven such that thesensors are braced in an upside−down position
to prevent baking on contaminants on to theglass lid.

Bake Recovery Procedure

The following bake out procedure is recommended tobake out trapped charges. The same procedure is applicable
if the image sensors have already been mounted on a PCB.
Equipment required: A clean oven rated up to 150C. It isrecommended to clean the oven with IPA solution.
Placement of the units or units mounted on a PCB: It is
recommended to place the units upside−down with the glass
lid surface not in contact with any surface, to prevent baking
on contaminants on to the glass lid.
A rack or railing can be used to brace the units. Ensure thatthe rack is also cleaned with IPA solution.
Bake−out procedure:

Disclaimer
onsemi is not responsible for damage caused by improper
handling, baking or cleaning of the device.

onsemi,, and other names, marks, and brands are registered and/or common law trademarks of Semiconductor Components Industries, LLC dba “onsemi” or its affiliates
and/or subsidiaries in the United States and/or other countries. onsemi owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property.
A listing of onsemi’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. onsemi reserves the right to make changes at any time to any
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and applications using onsemi products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information
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or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. ShouldBuyer purchase or use onsemi products for any such unintended or unauthorized application, Buyer shall indemnify and hold onsemi and its officers, employees, subsidiaries, affiliates,and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or deathassociated with such unintended or unauthorized use, even if such claim alleges that onsemi was negligent regarding the design or manufacture of the part. onsemi is an Equal
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