To investigate the impact of substrate roughness, crystal type, and coefficient of thermal expansion (CTE) on the stress of electroplated copper films, an experiment is conducted utilizing four distinct substrate types: smooth sapphire, rough sapphire, amorphous sintered alumina, and pure copper. The copper films are electroplated onto the substrate surfaces and subsequently annealed. Pre- and post-annealing measurements are taken to assess warp and a stress. Electron backscatter diffraction (EBSD) is employed to study the microstructural transformation of the copper films. The experimental results reveal that annealing transforms the copper film stress from compressive to tensile, with stress levels decreasing in the order of sintered alumina, smooth sapphire, rough sapphire, and pure copper substrates. Additionally, annealing leads to significant grain growth. Analysis indicates that post-annealing copper film stress arises from CTE mismatch and volume shrinkage. Stress reduction in copper films can be achieved by selecting rough single-crystal substrates and materials with CTEs close to that of copper. These experimental findings contribute valuable insights to the study of electroplating stress and the selection of appropriate electroplating.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |