Honours Profile: Allison Sibley

Allison Sibley is a fourth-year physics honours student. She is completing her research under the supervision of Ralf Brüning, who specializes in x-ray scattering.

Her thesis is tentatively entitled, “Substrate dependence of cantilever stress measurements for electroless copper deposition.” Sibley’s research tests the stress of electroless copper deposited onto different base materials, called substrates. Electroless copper deposition plays a key role in the manufacturing process for technologies such as circuit boards, and any stress in the deposit may cause problems with the functionality of the device.

To test for this stress, Sibley has been using dual-legged test strips that have been made from different types of substrate materials: metal alloys and plastics.

 The legs of each strip are treated to allow copper to deposit only on opposite sides. The test strips are then placed in a container of liquid that enables the deposition of copper. As the copper is depositing, the legs will spread apart because of the earlier treatment. Pictures are taken of the legs as they spread, and data is extracted from the images.

In industrial settings, electroless copper is deposited on metal substrates, yet the testing is completed using plastic. Sibley is comparing the results from the metal and plastic test strips to see if they yield consistent results. Preliminary results have shown consistencies, though there are features present on the plastic strips that are not present on the metal. It is good to know these differences, as the plastic and metal have different thermal expansion rates, which means that when the strips are cooled to room temperature, there is a jump toward compressive stress that is found on the plastic strips, but not in the metal.

 Sibley has co-authored a paper on her research with Brüning and colleagues that is set for publication. This will be Sibley’s second published paper during her undergraduate career. Sibley also presented her research at the Canadian Undergraduate Physics Conference that took place in October at McMaster University. Her ten-minute oral presentation took second place overall in the category of engineering and applied physics.

Sibley wasn’t always keen on studying physics. After much convincing from her engineer father, Sibley took physics in high school, where her teacher sparked her passion for the subject.

“He was passionate about physics, and hilarious—he made physics fun,” Sibley said.

Sibley was drawn to Mount Allison when she came for a tour. After meeting with faculty from the department, she knew Mt. A was the place for her.

“I love the way they do first-year physics here,” said Sibley, “When I visited, I knew that this was where I wanted to be.”

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