Method for making low-topography buried capacitor by a two stage etching process and device made
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsMong-Song Liang, Julie Huang, Tse-Liang Ying, Chen-Jong Wang
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Abstract
The present invention discloses a method for making low-topography buried capacitor including the steps of first depositing oxide layers, and then forming a small pre-contact hole by a dry etch method and a large contact hole by a wet etch method while using silicon nitride caps and sidewall spacers previously deposited on the word lines and on the bit lines as etch stop layers. A buried capacitor that has significantly improved topography can be fabricated in a semiconductor device.
Claims15
A method for making low-topography buried capacitor comprising the steps of:
- providing a pre-processed semi-conducting substrate having word lines and bit lines formed in-between oxide layers, said word lines and bit lines are insulated from said oxide layers by a nitride layer,
- forming a pre-contact hole having a first sloped sidewall exposing said semi-conducting substrate in a first contact area,
- forming a contact hole having a second sloped sidewall exposing said semi-conducting substrate in a second contact area larger than said first contact area, and
- depositing conductive layers and a dielectric layer sandwiched therein directly on said exposed second contact area forming said low-topography buried capacitor.
A method for making low-profile buried capacitor comprising the steps of:
- providing a front-end processed semi-conducting substrate having word lines and bit lines formed therein,
- insulating said word lines and said bit lines with nitride spacers,
- forming a pre-contact hole by a dry etching process utilizing said nitride spacers as etch-stop and exposing said semi-conducting substrate in a first contact area,
- forming a contact hole by a wet etching process exposing said semi-conducting substrate in a second contact area larger than said first contact area, and
- depositing conductive layers and dielectric layer directly on said exposed second contact area forming said low-profile buried capacitor.
Dependencies are inferred from the claim text.