| Summary: | 碩士 === 國立交通大學 === 國際半導體產業學院 === 107 === With the development of the Moore’s law, three-dimensional integrated circuits (3D ICs) play an important role by simplifying the packaging structure, utilizing the heterogeneous integration, and realizing the low RC delay in the semiconductor fabrication. Especially, the bonding technology is the key process of 3D ICs fabrication. By the bonding technology, the connection between three-dimensional devices could be realized with vertical stacking. With the decreased form factor, hybrid bonding technique turns into the essential part of 3D ICs. Therefore, the adhesion between polyimide and metal layer becomes a significant issue of the hybrid binding technique.
With high curing temperature, polyimide was seldom applied to the hybrid bonding fabrication in the past. On the contrary, because of the fact that polyimide is promising to be used in the hybrid bonding, there are two kinds of polymer with much lower curing temperature applied in this thesis. Considering possible metal materials including aluminum and nickel in hybrid bonding, the adhesion characteristics between the metal layer and the polyimide layer have been discussed in this thesis. Besides, due to the fact that the copper electroplating is widely used in the re-distribution layers (RDL), the copper electroplating influences the RDL structure seriously. This thesis also shows the influence of the copper electroplating on the adhesion of the titanium/copper layer and polyimide layer.
Based on the experimental results, the aluminum layer has the best adhesion to the polyimide compared to the nickel layer. Besides, the polyimide with higher curing temperature shows the better adhesion performance for the structure with aluminum layer compared to the polyimide with lower curing temperature. After the annealing process, the nickel structure shows that the adhesion between the polyimide layer and metal layer becomes worse. The result showing above reveals that adhesion becomes poor with increasing oxidation binding.
On the other hand, the adhesion condition between Ti/Cu and the polyimide with lower curing temperature is stable within 5-hour copper electroplating. Furthermore, in the electroplating process, the polyimide with lower curing temperature has better performance of adhesion compared to the polyimide with higher curing temperature. From the result above, the two kinds of polyimide can be applied in the metal/polymer hybrid bond. However, the polyimide with low curing temperature is more suitable for the electroplating process than the polyimide with high curing temperature. In conclusion, this thesis provides the basic adhesion condition under different polyimide materials, annealing conditions and copper electroplating time.
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