The Development of Tin Whiskers in Lead-free

SolderJoseph Garvey and Rachel Lindbergh – Co-Principal Investigators

Gabriel Voigt – Co-Investigator

Palmetto Scholars AcademyNorth Charleston, SC

Tin Whiskers● Small, crystalline structures● 0.006 to 10 micrometers thick

and up to 10 millimeters long● Have been known to cause

short circuits ● Causes are unknown--

theories say they could be caused by compression

Tin whiskers have degraded or destroyed…

● Galaxy IIIR● Galaxy VII ● Solidaridad 1● OPTUS B1● DBS-1● PAS-4● DirecTV 3

● Pacemakers● Patriot and Phoenix

missiles● Cellphones● Computers

Experiment Design

▪ 120 mm x 5 mm x 2 mm (99.3% tin, 0.7% copper) rectangular piece of tin made from tin solder (quantity of 4)

▪ 120 mm x 5 mm x 2 mm fiberglass, copper clad circuit board (quantity of 4) with a maximum of 4 mL of copper cladding; fiberglass is 0.1 cm in height, copper cladding is .06 cm in height

▪ Max of 3g of tin solder (percentage by weight): maximum of 97% tin; maximum of 4.2% silver; maximum of 3% hydrogenated rosin; maximum of 0.9% copper

▪ Polyethylene foam packing cylinders for securing test bed and PCBs in tube (10 cylinders -- 0.5 cm in diameter, 1.27 cm in depth)

Our FME

Key for test tubeThis is a depiction of what our type 1 FME will look like.Red= electroplated tin testbed 120 mm x 5 mm x 2mmOrange= printed circuit board 120 mm x 5 mm x 2 mmBlue= Polyethylene foam packing 0.5 cm in diameter, 1.27 cm in depthBlack= plugs to seal the test tubeWhite= test tube

Experiment Design

• 4 Type 1 FME’s will be constructed in the same manner according to the instructions above.

• 1 Type 1 FME will be randomly selected for spaceflight.

• The ground truth FME’s will be static but oriented in a different position:

• One ground truth FME will be oriented vertically

• One ground truth FME will be oriented upwards

• One ground truth FME will be oriented downwards

Our Goal

We want to determine whether spaceflight affects the development of tin whiskers

We expect that the FME that goes to the ISS will develop more tin whiskers than the ground truths.

Data Analysis

● Mass will be measured with a microscale from College of Charleston

● Solder will be analyzed with a scanning electron microscope from National Oceanic and Atmospheric Administration

AcknowledgementsPartners• Space and Naval Warfare Systems

Command (SPAWAR)• Center for the Advancement of

Science in Space (CASIS)• National Center for Earth and

Space Science Education• College of Charleston• Citadel University• Medical University of South

Carolina (MUSC)• National Oceanic and Atmospheric

Administration (NOAA)

Sponsors• ISHPI• Google• South Carolina Space Grant

Consortium• Center for the Advancement of

Science in Space (CASIS)