Plasma dielectric etch process including ex-situ backside polymer removal for low-dielectric constant material
First Claim
1. A plasma etch process, comprising:
- providing a workpiece having a porous carbon-doped silicon oxide dielectric layer;
defining a photoresist mask on a surface of the workpiece;
in an etch reactor;
performing a fluoro-carbon based etch process on the workpiece to etch exposed portions of the dielectric layer while depositing protective fluoro-carbon polymer on the photoresist mask;
transferring said workpiece to an ashing reactor and in said ashing reactor;
heating the workpiece to over 100 degrees C.;
exposing a peripheral portion of the backside of said workpiece; and
providing products from a plasma of a hydrogen process gas to reduce polymer and photoresist on said workpiece until the polymer has been removed from a backside of said workpiece.
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Accused Products
Abstract
A plasma etch process for etching a porous carbon-doped silicon oxide dielectric layer using a photoresist mask is carried out first in an etch reactor by performing a fluoro-carbon based etch process on the workpiece to etch exposed portions of the dielectric layer while depositing protective fluoro-carbon polymer on the photoresist mask. Then, in an ashing reactor, polymer and photoresist are removed by heating the workpiece to over 100 degrees C., exposing a peripheral portion of the backside of said workpiece, and providing products from a plasma of a hydrogen process gas to reduce carbon contained in polymer and photoresist on said workpiece until the polymer has been removed from a backside of said workpiece. The process gas preferably contains both hydrogen gas and water vapor, although the primary constituent is hydrogen gas. The wafer (workpiece) backside may be exposed by extending the wafer lift pins.
26 Citations
18 Claims
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1. A plasma etch process, comprising:
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providing a workpiece having a porous carbon-doped silicon oxide dielectric layer; defining a photoresist mask on a surface of the workpiece; in an etch reactor; performing a fluoro-carbon based etch process on the workpiece to etch exposed portions of the dielectric layer while depositing protective fluoro-carbon polymer on the photoresist mask; transferring said workpiece to an ashing reactor and in said ashing reactor; heating the workpiece to over 100 degrees C.; exposing a peripheral portion of the backside of said workpiece; and providing products from a plasma of a hydrogen process gas to reduce polymer and photoresist on said workpiece until the polymer has been removed from a backside of said workpiece. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A plasma etch process, comprising:
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providing plural workpieces each having a carbon-doped silicon oxide dielectric layer; defining a photoresist mask on a surface of each workpiece; in plural etch reactors; performing a fluoro-carbon based etch process on the respective workpieces in respective etch reactors simultaneously to etch exposed portions of the respective dielectric layers while depositing protective fluoro-carbon polymer on the respective photoresist masks; in an ashing reactor, performing the following steps on successive ones of the plural workpieces in a time window not exceeding that required to once perform said fluoro-carbon based etch process in each etch reactor; heating the workpiece to over 100 degrees C.; exposing a peripheral portion of the backside of said workpiece; and providing products from a plasma of a hydrogen process gas to reduce polymer and photoresist on said workpiece until the polymer has been removed from a backside of said workpiece. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification