Chartered Semiconductor Manufacturing Ltd (corporation)

Peter Hing

Alex See

Chen Feng

Lap Chan

Feng Dai

Pang Choong Hau

Chong Hau Pang

Pang Chong Hau

A new method of forming shallow trench isolations without using CMP is described. A plurality of isolation trenches are etched through an etch stop layer into the semiconductor substrate leaving narrow and wide active areas between the trenches. An oxide layer is deposited over the etch stop layer and within the trenches using a high density plasma chemical vapor deposition process (HDP-CVD) having a deposition component and a sputtering component wherein after the oxide layer fills the trenches, the deposition component is discontinued while continuing the sputtering component until the oxide layer is at a desired depth. In one method, the oxide layer overlying the etch stop layer in the wide active areas is etched away. The etch stop layer and oxide layer residues are removed to complete planarized STI regions. In another method, a second etch stop layer is deposited over the oxide layer using a HDP-CVD process whereby the second etch stop layer is sputtered away over the oxide layer overlying the first etch stop layer in the narrow active areas and whereby the second etch stop layer remains in the wide active areas. The second etch stop layer over the oxide layer in the wide active areas is etched away. The oxide layer overlying the first etch stop layer in the narrow and wide active areas is etched away. The first and second etch stop layers are removed to complete STI regions.

Method to achieve STI planarization

A process for forming insulator filled, shallow trench isolation (STI), regions in a semiconductor substrate, featuring a disposable polysilicon stop layer used to allow uniform insulator fill to be obtained, independent of shallow trench width, has been developed. The process features filling shallow trench shapes with a first high density plasma (HDP), deposited silicon oxide layer, followed by the deposition of the thin polysilicon stop layer, and a second HDP silicon oxide layer. After a planarizing chemical mechanical polishing procedure residual regions of the second HDP silicon oxide, still remaining in regions overlying the insulator filled shallow trench shapes, are selectively removed using the thin polysilicon layer as a stop layer. The polysilicon layer is then thermally oxidized. The thickness of the polysilicon layer can be varied such that the resultant polysilicon oxide layer serves to alleviate the possible oxide loss in the STI regions during subsequent clean processes.

Shallow trench isolation elevation uniformity via insertion of a polysilicon etch layer

A method of forming shallow trench isolations is described. An etch stop layer is deposited on the surface of a semiconductor substrate. A plurality of isolation trenches are etched through the etch stop layer into the semiconductor substrate to separate active areas. An oxide layer is deposited over the etch stop layer and within the isolation trenches wherein the oxide fills the isolation trenches and overlies the etch stop layer on the active areas. A polysilicon layer is deposited overlying the oxide layer within the isolation trenches and the oxide layer overlying the etch stop layer. The polysilicon layer is polished away until the oxide layer overlying the etch stop layer is exposed and the polysilicon layer remains only overlying the oxide layer in the isolation trenches. The polysilicon layer is oxidized whereby the oxidized polysilicon layer has a height close to the height of the oxide layer overlying the etch stop layer. The oxidized polysilicon layer, the oxide layer overlying the etch stop layer, and the oxide layer in the isolation trenches is polished down until the etch stop layer is reached thereby planarizing the isolation trenches to complete planarized shallow trench isolation regions in the manufacture of an integrated circuit device.

Method for pre-STI-CMP planarization using poly-si thermal oxidation

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Singapore, Singapore

Peter Hing