Final answer:
When a silicon wafer is subjected to a temperature difference across its thickness, it can warp due to thermal expansion. This is caused by the expansion and contraction of molecules in the material. The variation in expansion and contraction creates internal stresses that result in the warping of the wafer.
Step-by-step explanation:
When a silicon wafer is subjected to a temperature difference across its thickness, it is susceptible to warping. This is due to the phenomenon known as thermal expansion.
Thermal expansion is the tendency of an object to change in shape, volume, and dimension in response to changes in temperature. When a material, such as silicon, is heated, its molecules expand, causing the object to expand as well. Conversely, when the material is cooled, its molecules contract, resulting in the object shrinking.
The temperature difference across the thickness of the silicon wafer creates variations in expansion and contraction, leading to internal stresses and ultimately causing the wafer to warp.