april 2015 docid026684 rev 2 1 / 7 www.st.com TN1188 technical note chip storage and handling for aerospace products with silver backside introduction most stmicroelectronics aerospace products can be provided in die form with various quality levels. this document describes specific handling recommendations and instructions for products with a silver backside such as the rad - hard mosfet series.
contents TN1188 2 / 7 docid026684 rev 2 contents 1 purpose ................................ ................................ ............................. 3 2 definitions ................................ ................................ ......................... 3 3 materials and tools ................................ ................................ ........... 3 4 packi ng form description ................................ ................................ 4 4.1 packing information ................................ ................................ ........... 4 4.2 clay desiccant dimensioning ................................ ............................. 5 5 recommended storage instructions ................................ .............. 5 6 quality requirements ................................ ................................ ........ 5 7 revision history ................................ ................................ ................ 6
TN1188 purpose docid026684 rev 2 3 / 7 1 purpose the purpose of this document is to provide general handling instruction for aerospace products with silver backside. 2 definitions 1. waffle pack: 1 tray (with 1 antistatic interleaf on each tray ) + 1 cover and fixed by 1 clip 2. bulk: 4 waffle packs 3 materials and tools 1. waffle tray 2. tray cover 3. clip box 4. antistatic bag 5. clay desiccant 6. msl (moisture sensitivity level) card
packing form description TN1188 4 / 7 docid026684 rev 2 4 packing form description stmicroelectronics' aerospace packing procedure for products in die form is compliant with the standard packing and shipment rules summarized below. 1. maximum tray number per shielding bag: 4 2. traceability information related to die quality level is labeled outside the shielding bag. 4.1 packing information st aerospace dice are packe d in waffle packs inside a clean room (class 100, iso 5). each bulk includes a maximum of 4 waffle packs for shipment. the waffle packs are placed in antistatic bags and vacuum sealed. the detailed packing procedure for packing of products in die form is s ummarized below and illustrated in figure 1 . 1. a white interleaf is placed above each tray. 2. a cover is positioned on the top of each tray. 3. a clip keeps the cover on the tray. 4. a label is placed on the tray cover. 5. waffle packs are sealed under a vacuum in an inner antistatic bag (maximum 4 waffle packs per inner antistatic bag). 6. the whole package is placed in an outer antistatic bag (dry pack). 7. a bag of clay desiccant for dehumidification and an msl card (as a humidity indicator ) are placed on top side. 8. the antistatic bag is sealed in a vacuum sealer. any repacking should follow precisely the same procedure. figure 1 : aerospace die packing procedure
TN1188 recommended storage instruct ions docid026684 rev 2 5 / 7 4.2 clay desiccant dimensioning theoretical calculations and experimental tests show that there must be at least 2 grams of clay desiccant for 4 trays. each bulk includes 4 trays = 1 bag of desiccant = 2 grams. in ca se an inner bag is opened, the quantity of desiccant should be increased to 4 grams to ensure the proper humidity level . 5 recommended storage instructions st aerospace die products are packed in a clean - room environment. it is recommended to store these products in a similar environment. the following key storage precautions should be observed: ? the die must be maintained in a filtered nitrogen atmosphere unt il removed for assembly. ? the moisture content of the storage facility must be maintained at 30 percent 10 percent relative humidity. ? electrostatic discharge (esd) damage precautions are necessary during handling. the die must be in an esd - protected enviro nment at all times for inspection and assembly. dice contained in waffle trays can remain in storage for up to one year under these conditions. if a visual inspection is required, it is recommended to repack the dice immediately afterward, following the re commendations above, or to bond them immediately. 6 quality requirements trays use for packing must not be damaged (i.e. cracked, broken or chipped.) a change of the wa ffle pack is considered a minor change, which st will only notify the customer about. st standard rules on product change notifications (pcns) apply only to changes affecting the die itself.
revision history TN1188 6 / 7 docid026684 rev 2 7 revision history table 1: document revision history date revision changes 22 - sep - 2014 1 initial release. 17 - apr - 2015 2 first public release.
TN1188 docid026684 rev 2 7 / 7 important notice C please read carefully stmicroelectronics nv and its subsidiaries (st) reserve the right to make changes, corrections, enhancements, modifications , and improvements to st products and/or to this document at any time without notice. purchasers should obtain the latest relevant information on st products before placing orders. st products are sold pursuant to sts terms and conditions of sale in place at the time of or der acknowledgement. purchasers are solely responsible for the choice, selection, and use of st products and s t assumes no liability for application assistance or the design of purchasers products. no license, express or implied, to any intellectual property right is granted by st herein. resale of st products with provisions different from the information se t forth herein shall void any warranty granted by st for such product. st and the st logo are trademarks of st. all other product or service names are the property of their respective owners. information in this document supersedes and replaces information previously supplied in any prior versions of this document. ? 2015 stmicroelectronics C all rights reserved
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