Die singulation method
| DWPI Title: Method for singulating die from e.g. silicon-on-insulator substrate, involves providing release fixture proximate to semiconductor substrate during step of etching away oxide layer between first and second trenches |
| Abstract: A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with an HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die. |
| Use: Method for singulating a die from a semiconductor substrate e.g. semiconductor-on-insulator substrate such as silicon-on-insulator substrate (claimed) or bulk silicon substrate e.g. semiconductor wafer. |
| Advantage: The method allows the release fixture to prevent the singulated die from dropping down to a bottom of a tank or chamber containing the hydrofluoric etchant and allow the singulated die to be easily removed at once from the hydrofluoric etchant while minimizing potential damage to the singulated die from handling. The method enables visually observing completion of singulating the die so as to provide a convenient indicator of the completion of releasing the microelectromechanical system (MEMS) device on the die, avoid a need for a precise timing of the etching process and avoid over etching of the oxide layer beneath the MEMS device. The method allows the release fixture to be provided with openings through the fixture so as to provide access for an etchant comprising hydrofluoric acid to enter the first trench so as to allow the oxide layer to be etched away from the trenches during the etching process, thus reducing a time required for etching away the oxide layer between the trenches. |
| Novelty: The method (100) involves etching a first trench into a semiconductor substrate and a semiconductor layer around a die to-be-singulated (104). A second trench is etched (106) into another semiconductor substrate and the semiconductor layer around the die to-be-singulated. An oxide layer is etched away (108) between the first trench and the second trench to singulate the die from each semiconductor substrate. A release fixture is provided (110) proximate to each semiconductor substrate during a step of etching away the oxide layer between the first and second trenches. |
| Filed: 4/16/2013 |
| Application Number: US13863509A |
| Tech ID: SD 11059.1 |
| 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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