Ozone Etch and Hydrogen Radical Treatment for Ruthenium Removal
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Solution Overview
Problem
Chemical mechanical polishing (CMP) processes often fail to effectively remove ruthenium layers and can damage low-k dielectric material layers and cause surface oxidation of copper layers in semiconductor manufacturing, leading to incomplete removal and layer damage.
Innovation Solution
A method involving an ozone etch process to remove the ruthenium layer and a hydrogen radical treatment process to remove oxide residues and anneal the copper layer, both performed in the same processing chamber to minimize damage and enhance removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP process is used to remove copper layer, then copper removal is achieved, but ruthenium layer removal is incomplete and low-k dielectric material layers are damaged
Solution Approach 1:
The invention segments the layer removal process into distinct steps: CMP for copper removal, followed by ozone etching for ruthenium removal. This segmentation allows each process to be optimized for its specific function without compromising other layers, solving the contradiction between complete copper removal and protection of low-k dielectric layers.
Solution Approach 2:
The invention introduces ozone gas as an intermediary substance to selectively remove ruthenium layers after CMP processing. The ozone etching process acts as a mediator that completes the ruthenium removal without damaging the low-k dielectric material layers that were damaged by the CMP process alone.
2Manufacturing precision
If CMP process is used for polishing, then copper layer is removed, but surface oxidation of copper layers occurs
Solution Approach 1:
The invention applies preliminary protective actions by controlling the CMP process parameters and immediately following with ozone etching, which prevents surface oxidation of the copper layer. The sequential process design ensures that copper surfaces are treated in a controlled environment that minimizes oxidation.
3Manufacturing precision
If multiple processing steps are used for layer removal, then removal completeness is improved, but processing time and complexity increase
Solution Approach 1:
The invention merges the copper removal and ruthenium removal processes into a single integrated flow by immediately transitioning from CMP to ozone etching in sequence within the same processing system. This combining of operations achieves complete layer removal while minimizing the total processing time and avoiding the need for separate, standalone processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method allows for robust removal of ruthenium layers without damaging low-k dielectric material layers and reduces oxide residues on copper layers, while also providing annealing benefits, all within a single processing chamber for efficiency and cost-effectiveness.
Implementation Method 1
performing an ozone etch process on the ruthenium layer to at least partially remove the ruthenium layer, wherein the ozone etch process comprise exposing the workpiece to a process gas containing ozone gas
Implementation Method 2
performing a hydrogen radical treatment process on the workpiece to remove at least a portion of an oxide layer present on the copper layer
Implementation Method 3
energizing an induction coil to generate a remote plasma containing one more etch species from the second process gas
Data Source
AI summary
Methods for processing a workpiece are provided. The workpiece can include a ruthenium layer and a copper layer. In one example implementation, a method for processing a workpiece can include supporting a workpiece on a workpiece support. The method can include performing an ozone etch process on the workpiece to at least a portion of the ruthenium layer. The method can also include performing a hydrogen radical treatment process on a workpiece to remove at least a portion of an oxide layer on the copper layer.