Sloped contact etch process
AssigneeMotorola, Inc.
InventorsRobert K. Berglund, Karl E. Mautz
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Abstract
A method for etching vias having sloped sidewalls is provided, wherein the vias are formed in an interlayer dielectric formed on top of an interconnect layer using a patterned photoresist film as a mask. A top portion of the via is formed with a wet etch process which isotropically undercuts the masking film thereby creating a sloped sidewall. A bottom portion of the via is formed by a dry etch process comprising the steps of alternating between a number of isotropic mask erosion steps and a number of anisotropic dielectric etch steps, so that the interlayer dielectric exposed to the anisotropic etch by the mask opening is enlarged with each mask erosion step. Thus, a slope is created on the dry etched portion of the via sidewall as well as the wet etched portion of the via sidewall.
Claims13
A method for making electrical contact between a first conductive layer and a second conductive layer of a semiconductor device wherein an insulating layer separates the first conductive layer and the second conductive layer, the method comprising the steps of:
- forming a masking film with a predetermined pattern on the surface of the insulating layer;
- isotropically etching a portion of the insulating layer exposed by the pattern;
- anisotropically etching the exposed portion of the insulating layer using the masking film as a mask;
- completing removal of the exposed portion of the insulating layer, thus exposing a portion of the first conductive layer, by repeating the steps of isotropically etching the masking film in a horizontal direction and anisotropically etching the insulating layer in a vertical direction;
- removing the masking film;
- and forming the second conductive layer on top of the insulating layer in electrical contact with the first conductive layer.
A method for forming a hole in a layer formed on a semiconductor substrate comprising the steps of:
- forming a masking film with a predetermined pattern on the surface of the layer;
- isotropically etching a portion of the layer exposed by the pattern;
- anisotropically etching the portion of the exposed layer using the masking film as a mask;
- completing removal of the layer by repeating the steps of isotropically etching the masking film in a horizontal direction and anisotropically etching the portion of the layer in a vertical direction to form the hole in the layer.
Dependencies are inferred from the claim text.