Cypress Failure Analysis Request - KBA225847

Version: **

 

Cypress Return Policy

Failure analysis of returned units is a service Cypress provides on products purchased directly from Cypress or authorized distributors. The purpose of the failure analysis is to resolve the customer’s issue and to use the results to improve Cypress quality.

Overview

This document provides the recommended verification, handling and shipping procedures for units returned to Cypress for failure analysis. Following these recommendations will create the best opportunity for Cypress to provide customers with accurate results.

You must take proper care when returning units or boards to Cypress for failure analysis.   Improper handling can result in further damage and prevent a correct diagnosis of the problem. This will cause delays in the analysis and may result in wrong or ineffective corrective actions that do not address the actual problem.

Return Procedure

  1. Verify and document the failure.

    ·         Confirm the failure and verify that it is caused by a Cypress device.

    Note that a failure analysis request may be rejected if you do not verify the failure.

    ·         Document the failure mode in as much detail as possible. More details about the failure will help determine the root cause.

    ·         Board- and Flex-mounted units must be baked prior to using high-temperature de-soldering steps to remove the unit. This is to prevent any damage due to moisture-related delamination. Refer to IPC/JEDEC J-STD-033C (or latest revision) section 6, “BOARD REWORK,” for information about removing units without damage.

    ·         Use ABA swap testing to verify that the failure is associated only with the Cypress unit – fig 1.

    o   For wireless products, you must complete an ABA swap test to verify the failure.

    o   The ABA requirement is in Cypress PIN 174101,http://www.cypress.com/documentation/product-information-notice-pin/pin174101


    Figure 1. ABA Swap Test

  2. Identify the samples (units and/or boards) for analysis 

    ·         If returning multiple units, each unit must be clearly marked so Cypress can identify the part. The marking may be on the unit or on the sealed ESD bag with the unit inside.

    ·         Inspect units for mechanical damage – see Figure 2.

    ·         Units with missing or damaged leads cannot be functionally tested and must not be returned – see Figure 3.

    ·         Units must be cleaned of residue flux and solder before returning to Cypress – see Figure 4

    .

                   Figure 2. Example of Package Crack
                                 

                   Figure 3. Example of Damaged Package Leads

                                          
                   Figure 4. Example of Unit Not Cleaned After bboard Removal

     

  3. Create an analysis request using the MyCases link on the Cypress.com web page
    ·    Go to the Cypress.com web page and log into your MyCases account.
          https://www.cypress.com/user/login?destination=node/527946
    ·     Create a MyCase by selecting the Failure Analysis link.
    Untitled.png
    ·    
    Complete the form and submit.

     

    Cypress will review the request and respond within one business day. Cypress may request additional information.  Based on the request, a shipping address will be provided by Cypress.

     

  4. Prepare the samples for shipment 

     

    ·      Proper packing is important to protect the device from mechanical and electrostatic (ESD) damage. Whenever possible, return the units in the original Cypress packaging.

    ·         All returns should be clearly marked with the customer’s ID number.

    ·         The MyCase number should be on the shipping label and inside the shipment. The MyCase number is critical to allow the correct identification of the units when received at Cypress.

    ·         Physical protection can be accomplished using a stiff container and/or packing foam or packing peanuts.

    ·         Electrostatic protection can be a separate item such as a shielded bag or part of the container used for physical protection. Possible sources of containers are listed below.

    o   http://protektivepak.descoindustries.com/

    o   http://staticcontrol.descoindustries.com/SCSCatalog/Bags/Static-Shielding-Bags/

    o   http://www.qsource.com/m-92-conductive-containers-inc-cci.aspx

                                                                                     

                                     Figure 5. Various Electrostatic Protection Methods

     

    Ensure that you adhere to the following basic packing recommendations:

    ·         For QFN, BGA, or low pin count (<20) leaded packages, use an antistatic bag. Each bag must contain only one device to avoid mechanical damage. The bag should be labeled with the unit serial number and failure description.

    ·         High pin count (>20) leaded packages must be secured in a shipping tray to protect pins. If there are multiple units in a single tray, the units should be labeled in a manner to allow proper identification.

    ·         For WLCSP packages:

    o   Improper handling of WLCSP units can result in damage – see Figure 6. This will prevent Cypress from determining the root cause of the customer’s failure.

    o   Do not use metal tweezers to handle or manipulate the WLCSP units because doing so can result in damage to the package – see Figure 7

    o   Use a vacuum pen or plastic tweezers to place each WLCSP unit into a separate small ESD bag.

    o   Place only one unit per bag

    o  Do not ship the WLCSP in a flat envelope because this does not provide sufficient protection from physical damage.

                  1Untitled.png

                    Figure 6. WLCSP Package Damage due to Mechanical Impact at Corner 
                  

                   Figure 7. WLCSP Package Damage due to Using Metal Tweezers

  5. Communicate the shipment tracking number and shipper to Cypress through the MyCases Analysis Request.
    · Update the MyCase with the shipping information – Shipper and Tracking Number. This will allow Cypress to review the shipment status and determine whether there are any issues with the shipment
    ·  If shipping information is not provided within five days, Cypress will cancel the request.

  6. When possible, return an unused unit for comparison.
    · Returning an unused unit will help Cypress to quickly compare the test results between a good and bad unit from the same assembly lot
    · Functional properties vary due to normal statistical variation. These normal variations may cause sensitivities in the customer’s specific application. Comparing a good sample from the same lot can help determine whether there is any functional difference between the good and failing units

  7. Cypress responsibility during the analysis 
    • Cypress will provide an analysis update every 10 days.
    • All communication will be via email using the Cypress MyCase system.
    • The customer may respond directly to the email using ‘Reply’ or ‘Reply to All’. Do not modify the email subject line as this is used by the Cypress system to direct the incoming email to the proper location.
    • Example of an email from MyCase system:
    • If you do not receive email updates, it may indicate that there is an issue with your firewall setting or that the emails are being redirected to a junk mail folder. If this occurs, check your Junk E-mail folder or access the case directly using your Cypress MyCase account.

  8. Analysis Conclusion
    • At the completion of the analysis, Cypress will provide the customer a final report detailing the analysis results.
    • You will be asked if there are any further questions. If you do not provide any further questions, the request will be closed.
    • After closure, a survey will be sent to the customer. The results and comments from these surveys are used to improve the Customer Failure Analysis process.

          In summary, following these procedures will provide the best chance of a successful analysis and the customer’s problem resolution.

 

References

IPC/JEDEC J-STD-033

Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices