ScAIN etch mask for highly selective etching
| DWPI Title: Etching method for semiconductor fabrication involves removing scandium aluminum nitride (ScAlN) etch mask from surface of substrate after etching substrate through one opening in ScAlN etch mask using fluorine-based etch chemistry |
| Abstract: A fabrication process employing the use of ScAlN as an etch mask is disclosed. The ScAlN etch mask is chemically nonvolatile in fluorine-based etch chemistries and has a low sputter yield, resulting in greater etch mask selectivity and reduced surface roughness for silicon and other semiconductor materials. The ScAlN etch mask has an etch mask selectivity of greater than 200,000:1 relative to silicon compared to an etch mask selectivity of less than 40,000:1 for a prior art AlN etch mask relative to silicon. Further, due to reduced sputtering of the ScAlN etch mask, and thus reduced micromasking, the ScAlN etch mask yielded a surface roughness of 0.6 μm compared to a surface roughness of 2.8 μm for an AlN etch mask. |
| Use: Etching method for semiconductor fabrication. |
| Advantage: Reduces amount of wafer bow induced by film stress resulting in shorter deposition time by minimizing etch mask thickness. Ensures high selectivity in etch masks to reduce undesired artifacts in etch profiles such as sidewall tapering, while enabling use of thinner etch mask films. Obtains etch mask for Deep Reactive Ion Etching (DRIE) which is chemically non-volatile in fluorine-based etch chemistry while also having low sputter yield and creating high etch mask selectivity relative to silicon and other semiconductor materials. |
| Novelty: The etching method involves providing a substrate and forming a layer of ScAlN etch mask material on the surface of a substrate (100). A ScAlN etch mask (130) is formed from the layer of ScAlN etch mask material and includes one opening. The substrate is etched through the opening in the ScAlN etch mask using a fluorine-based etch chemistry. The ScAlN etch mask is removed from the surface of the substrate. |
| Filed: 8/12/2019 |
| Application Number: US16537953A |
| Tech ID: SD 14419.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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