Defect gettering by induced stress
AssigneeIntersil Corporation
InventorsJose A. Delgado, Craig J. McLachlan
Life of this patent
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Abstract
The present invention induces provides a gettering trench on the front surface of a device substrate. In one embodiment it induces stress and simultaneously forms a gettering zone 40 for gettering impurities in an integrated circuit structure. In another embodiment, the trench is filled with gettering material 72 such as polysilicon. The two gettering mechanisms may be combined 82,84. The invention is useful for providing gettering in bonded wafers and in silicon-on-insulator devices (FIGS. 4,5).
Claims16
A method of forming an integrated circuit structure comprising the steps of:
- providing a monocrystalline semiconductor device substrate having an upper portion suitable for device formation;
- dividing the upper portion of said semiconductor substrate into at least one inactive region and at least one active region;
- forming at least one active device in the active region;
- etching a gettering trench in the front surface of the substrate in the inactive region and spaced from the active region;
- depositing an oxide layer on the sidewalls and floor of the gettering trench;
- depositing a layer of polysilicon on the oxide layer to underfill the trench, leaving a void near the middle of said trench;
- and
- oxidizing at least a portion of the deposited polysilicon thereby closing the void and stressing the device substrate and inducing a region of crystal lattice defects in the device substrate in a region surrounding the gettering trench for attracting impurities toward said trench and away from the active region.
A method of forming an integrated circuit structure comprising the steps of:
- providing a monocrystalline semiconductor device substrate having an upper portion suitable for device formation;
- dividing the upper portion of said semiconductor substrate into at least one inactive region and at least one active region;
- forming at least one active device in the active region;
- etching a gettering trench in the front surface of the substrate in the inactive region and spaced from the active region;
- covering the sidewalls and floor of the gettering trench with polysilicon, thereby providing a gettering mechanism;
- filling the gettering trench with polysilicon and planarizing said polysilicon;
- and
- underfilling the gettering trench with polysilicon and oxidizing a portion of said polysilicon, thereby creating a stress gettering zone around said gettering trench and providing a second gettering mechanism.
Dependencies are inferred from the claim text.