(TI)对半导体器件的长期存储评估.pdf - 第14页

15 Glossary of T erms BGA Ball Grid Array Package – a package with solder balls (globules) attached at the package bottom side for electrical contact. Desiccant A hygroscopic substance used to remove moisture from moistu…

12 Summary of Results

• Reliability of the semiconductor devices stored in an environmentally controlled warehouse for an extended

period of time up to 21 years was assessed. No failure mechanisms were identified.

• ESD performance of tape and reel samples was comparable to new tape and pocket samples.

• The HIC were confirmed to be functional after LTS.

• The desiccant used for moisture sensitive product is active for >15 years.

• No degradation in ESD performance or moisture ingress was observed on the MBB when stored in a

controlled environment.

• Solderability of the package pins met all expectations and is comparable with the solderability performance of

current devices.

13 Conclusion

Advancements in lead-frame technology, packing materials, work methods, and inventory logistics have made it

possible to further extend the time between manufacturing semiconductor products and delivering to customers.

This extended storage time does not impact product performance or the customers product shelf life. In multiple

studies performed since 1998, no evidence of diminishing reliability has been found that would adversely affect

the product or the ability for it to be soldered to a PCB. No failure mechanisms have been identified that would

compromise the circuit reliability of LTS devices. Based on these studies, TI will eliminate limitations on the

storage durations. TI will continue to collect data on more samples and as the data directs, TI will continue to

adjust the storage conditions and duration for various products.

14 Acknowledgments

The author wishes to recognize the following individuals and groups for their professional assistance:

• Andreas Pfeiffer and Markus Filbry, TI Germany, solderability testing and documentation of the 2020 long

term storage study results.

• TI technical staff members who collaborated and contributed to the evaluation efforts.

• The TI Reliability Laboratory in Freising, Germany and Dallas, Texas.

• Dallas Device Analysis Operation (DDAO) and Freising Device Analysis Operation (FDAO).

• Todd Wyant, TI Dallas, packaging support.

• Ron Eller, TI Dallas, technical assistance.

• Ron Madsen, TI Tucson, retired.

www.ti.com Summary of Results

SLPA019 – SEPTEMBER 2021

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Long Term Storage Evaluation of Semiconductor Devices 13

15 Glossary of Terms

BGA Ball Grid Array Package – a package with solder balls (globules) attached at the

package bottom side for electrical contact.

Desiccant A hygroscopic substance used to remove moisture from moisture barrier bags.

Humidity Indicator

Card

(HIC) – a card printed with a moisture sensitive chemical (cobalt chloride) that changes

from blue to pink in the presence of water vapor.

Long Term Storage (LTS) – storage of devices in an uncontrolled indoor environment for more than two

years. In some publication also Extended Shelf Life (ESL) is used.

Moisture Barrier Bag (MBB) – storage bag manufactured with a flexible laminated vapor barrier film that

restricts transmission of water vapor (also called Dry Pack Back).

Nickel, Palladium,

Gold

(NiPdAu) – metal layers that are pre-plated on leadframes to enable solderability.

NiPdAu Nickel, palladium, gold – composition of lead finish which is plated on the bare copper

leadframe with nickel being the first on the copper and followed by palladium and gold

plating step.

NiPdAuAg Is a variation in the industry where the AuAg plating is a composition in the plating bath.

QFN Quad Flat no Leads package – a package with flat contact areas at the package bottom

for electrical contacts.

QFP Quad Flat package – a package with formed metal leads at the package sides for

electrical contacts.

SAC / SnAgCu Solder paste metal composition, tin, silver, copper content.

Shelf Life The time that moisture sensitive devices may be stored in MBB with desiccant and HIC

or MSL 1 devices stored at room ambient.

Sn Tin, composition of lead finish which is plated on the bare copper leadframe surfaces

extending the package after the package encapsulation process completed.

SOIC Small Outline Integrated Circuit package – a package with formed metal leads at the

package sides for electrical contacts.

SOT Small Outline Transistor Package – a package with formed metal leads at the package

sides for electrical contacts.

Water Vapor

Transmission Rate

(WVTR) – a measure of permeability of MBBs to water vapor.

WCSP Wafer Chip Scale Package or Die Size BGA – silicon die with attached solder balls or

globules at the bottom of the package for electrical contact.

16 References

1. JEDEC Publication JEP160, (2011). Long-Term Storage for Electronic Solid-State Wafers, Dice, and

Devices. Retrieved from https://www.jedec.org/standards-documents/

2. NEDA Publication, (2002). Managing Date Code Restrictions on Orders for Electronic Components.

Retrieved from https://www.ecianow.org/assets/docs/GIPC/

3. Texas Instruments, BGA Package Component Reliability After Long-Term Storage application note

4. Texas Instruments, Component Reliability After Long Term Storage technical white papers

5. Texas Instruments, Shelf-Life Evaluation of Lead-Free Component Finishes application reports

6. Texas Instruments, Shelf -Life Evaluation of Nickel/Palladium Lead Finish for Integrated Circuits application

reports

Glossary of Terms www.ti.com

14 Long Term Storage Evaluation of Semiconductor Devices SLPA019 – SEPTEMBER 2021

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