ADDITION OF BALLAST HYDROCARBON GAS TO DOPED POLYSILICON ETCH MASKED BY RESIST
First Claim
1. A method for etching a gate on a semiconductor wafer comprising:
- providing a semiconductor wafer having a photo resist layer with varying patterns with varying concentrations of hydrocarbons over a gate layer;
providing said semiconductor wafer within a processing chamber;
flowing an etchant into said processing chamber;
contacting said etchant to said semiconductor wafer to generate varying concentrations of a hydrocarbon-containing reaction by-product across said varying patterns of said photo resist layer;
adding a gas within said processing chamber to compensate for said varying concentrations of said hydrocarbon-containing reaction by-product across said varying patterns by forming a homogeneous etchant having a uniform concentration of hydrocarbons across the entire said semiconductor wafer;
maintaining said homogeneous etchant across said entire semiconductor wafer by controlling an amount of said hydrocarbon gas added to said processing chamber;
etching a gate in said gate layer by contacting said gate layer with said homogeneous etchant; and
simultaneously, depositing a passivation layer over all exposed surfaces during said etching using said homogeneous etchant having said uniform concentration of hydrocarbons to provide uniform etching results.
5 Assignments
0 Petitions
Accused Products
Abstract
A chemical composition and method for providing uniform and consistent etching of gate stacks on a semiconductor wafer, whereby the composition includes an etchant and an added ballast gas added. The gate stacks are formed using this combined etchant and ballast gas composition. The ballast gas may either be similar to, or the equivalent of, a gaseous byproduct generated within the processing chamber. The ballast gas is added in either an overload amount, or in an amount sufficient to compensate for varying pattern factor changes across the water. This etchant and added ballast gas form a substantially homogeneous etchant across the entire wafer, thereby accommodating for or compensating for these pattern factor differences. When etching the wafer using this homogeneous etchant, a passivation layer is formed on exposed wafer surfaces. The passivation layer protects the lateral sidewalls of the gate stacks during etch to result in straighter gate stacks.
21 Citations
23 Claims
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1. A method for etching a gate on a semiconductor wafer comprising:
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providing a semiconductor wafer having a photo resist layer with varying patterns with varying concentrations of hydrocarbons over a gate layer; providing said semiconductor wafer within a processing chamber; flowing an etchant into said processing chamber; contacting said etchant to said semiconductor wafer to generate varying concentrations of a hydrocarbon-containing reaction by-product across said varying patterns of said photo resist layer; adding a gas within said processing chamber to compensate for said varying concentrations of said hydrocarbon-containing reaction by-product across said varying patterns by forming a homogeneous etchant having a uniform concentration of hydrocarbons across the entire said semiconductor wafer; maintaining said homogeneous etchant across said entire semiconductor wafer by controlling an amount of said hydrocarbon gas added to said processing chamber; etching a gate in said gate layer by contacting said gate layer with said homogeneous etchant; and simultaneously, depositing a passivation layer over all exposed surfaces during said etching using said homogeneous etchant having said uniform concentration of hydrocarbons to provide uniform etching results. - View Dependent Claims (2)
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3. (canceled)
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4. A method for etching a gate on a semiconductor wafer comprising:
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providing a semiconductor wafer within a processing chamber, said semiconductor wafer having a patterned photo resist layer with varying concentrations of hydrocarbons over a gate layer; flowing an etchant into said processing chamber; contacting said etchant to said semiconductor wafer to generate a hydrocarbon-containing reaction by-product that is diffused throughout said etchant at varying concentrations across said semiconductor wafer; adding a hydrocarbon gas within said processing chamber to equilibrate said varying concentrations of said hydrocarbon-containing reaction by-product and provide a homogeneous etchant across the entire said semiconductor wafer; and etching a gate into said gate layer using said patterned photo resist layer by contacting said gate layer with said homogeneous etchant, while simultaneously depositing a passivation layer over all exposed surfaces during said etching to provide uniform etching results. - View Dependent Claims (7, 8, 9, 10, 14, 15, 16, 21, 22, 23)
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5. (canceled)
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6. (canceled)
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11-13. -13. (canceled)
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17-20. -20. (canceled)
Specification