Method to prevent gate oxide damage by post poly definition implantation
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJyh-Haur Wang, Chih-Heng Shen
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Abstract
A method for preventing gate oxide damage caused by post poly definition implantation is disclosed. It is shown that the antenna ratio that is correlatable to oxide damage can be reduced and made to approach zero by implementing a mask layout during ion implantation. This involves covering all of the polysilicon electrodes with a photoresist mask, and reducing the effective antenna ratio to zero, and performing ion implantation to form source/drain regions thereafter. In this manner, the dependency of ion implantation to pattern sensitivity is also removed.
Claims12
A method for preventing oxide damage comprising the steps of:
- providing a substrate having polysilicon electrodes over an oxide layer;
- forming photoresist mask completely covering said polysilicon electrodes, wherein said photoresist provides coverage during all ion implantation steps in order to prevent oxide damage during any subsequent ion implantation;
- and
- performing on implantation to form heavily doped source/drain regions in said substrate prior to the removal of said photoresist mask.
A method for preventing oxide damage comprising the steps of:
- providing a substrate having field oxide regions;
- growing gate oxide over said substrate;
- performing first ion implantation to adjust threshold voltage;
- depositing polysilicon layer over said substrate;
- patterning said polysilicon layer;
- forming photoresist mask completely covering said polysilicon electrodes, wherein said photoresist provides coverage during all subsequent ion implantation steps in order to prevent oxide damage during any subsequent ion implantation;
- and
- performing a second ion to form heavily doped source/drain regions in said substrate prior to the removal of said photoresist mask.
Dependencies are inferred from the claim text.