Selective Silicon Oxide Deposition on Dielectrics via Copper Blocking
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Solution Overview
Problem
Conventional semiconductor fabrication techniques face challenges in selectively depositing silicon oxide on copper surfaces, leading to misalignment and defects such as 'unlanded vias' and 'fang' defects due to the inability to achieve fully aligned vias, which affects device performance and reliability.
Innovation Solution
A method involving the use of a copper-blocking reagent like alkyl thiol to selectively adsorb on copper surfaces, followed by exposure to a silicon-containing precursor and mild oxidizing plasma to deposit silicon oxide, while a reducing agent reduces the copper surface, allowing for selective deposition of silicon oxide on dielectric materials relative to copper surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition techniques are used to deposit silicon oxide on copper surfaces, then silicon oxide can be deposited, but copper oxidation occurs and alignment precision deteriorates leading to unlanded vias and fang defects
Solution Approach 1:
A copper-blocking reagent is applied to the copper surface before silicon oxide deposition to prevent copper oxidation. This preliminary protective action ensures that the copper surface remains intact and properly aligned during the subsequent silicon oxide deposition process, eliminating unlanded vias and fang defects.
Solution Approach 2:
A copper-blocking reagent acts as an intermediary substance between the copper surface and the silicon oxide deposition environment. This reagent selectively adsorbs onto the copper surface, preventing direct interaction between copper and oxidizing species while allowing silicon oxide to deposit on dielectric surfaces with high alignment precision.
2Reliability
If a copper-blocking reagent is used to prevent copper oxidation, then copper protection is achieved, but process complexity increases due to additional process steps
Solution Approach 1:
The copper-blocking reagent application is combined with the existing deposition process sequence, where the reagent is applied and then the silicon oxide deposition follows in an integrated manner. This merging approach protects copper reliability while maintaining process efficiency by consolidating steps.
Solution Approach 2:
The process utilizes parameter changes in the form of a reducing agent that converts copper oxide back to metallic copper. By changing the chemical state of copper through reduction, the process maintains copper protection while managing the complexity through controlled chemical transformations rather than adding purely mechanical steps.
3Manufacturing precision
If reducing agent is used to reduce copper oxide, then copper surface is restored, but deposition control becomes more difficult due to competing reactions
Solution Approach 1:
The process employs periodic action by sequentially applying the copper-blocking reagent before deposition and then applying the reducing agent after deposition. This periodic treatment ensures copper surface restoration without interfering with the silicon oxide deposition control, as the reducing action occurs at a different time when deposition is complete.
Solution Approach 2:
The copper-blocking reagent is applied in advance before silicon oxide deposition to prevent copper oxidation during the deposition process. This preliminary protection simplifies deposition control by preventing competing reactions between copper and oxidizing species during the critical deposition phase, while still allowing reducing agent treatment afterward if needed.
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
This approach enables the selective deposition of silicon oxide on dielectric materials relative to copper surfaces, achieving fully aligned vias and improving device performance by preventing copper oxidation and ensuring precise alignment, thereby reducing defects and enhancing the reliability of semiconductor devices.
Implementation Method 1
exposing the substrate to a copper-blocking reagent to selectively adsorb onto the exposed copper metal surface
Implementation Method 2
exposing the substrate to an oxidizing plasma generated in an environment comprising a weak oxidant to convert the adsorbed silicon-containing precursors to silicon oxide
Implementation Method 3
exposing the substrate to a reducing agent to reduce the exposed copper metal surface
Data Source
AI summary
Methods and apparatuses for selectively depositing silicon oxide on surfaces relative to a metal-containing surface such as copper are provided. Methods involve exposing a substrate having hydroxyl-terminated or dielectric surfaces and copper surfaces to a copper-blocking reagent such as an alkyl thiol to selectively adsorb to the copper surface, exposing the substrate to a silicon-containing precursor for depositing silicon oxide, exposing the substrate to a weak oxidant gas and igniting a plasma, or water vapor without plasma, to convert the adsorb silicon-containing precursor to form silicon oxide. Some methods also involve exposing the substrate to a reducing agent to reduce any oxidized copper from exposure to the weak oxidant gas.