Semiconductor Cleaning Method for Contact Holes
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Solution Overview
Problem
In semiconductor manufacturing, the physical bombardment process used for cleaning often results in byproduct deposition within small features, leading to increased resistance and uneven surfaces, which can cause leakage current issues and enlarge feature sizes.
Innovation Solution
A cleaning method combining a physical cleaning process using argon to partially remove oxides and a fluorine-based chemical cleaning process with ammonia and nitrogen trifluoride, followed by a thermal process to remove the byproduct (NH4)2SiF6, ensuring equal lateral etched thicknesses of material layers to maintain smoothness and prevent feature enlargement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a physical bombardment process using argon ions is used to clean oxides from semiconductor components, then oxides are removed from surfaces, but byproducts are deposited in small through holes causing increased resistance and uneven surfaces
Solution Approach 1:
The cleaning process is divided into multiple sequential steps: first a physical bombardment process to remove bulk oxides, then a chemical cleaning process to remove byproducts and clean remaining oxides. This segmentation allows each process to target specific cleaning needs without the downsides of using a single aggressive method.
Solution Approach 2:
A chemical cleaning process using fluorine-based chemistry acts as an intermediary step between the physical bombardment process and the final cleaned state. This intermediary process converts and removes byproducts that would otherwise damage the semiconductor features, bridging the gap between rough oxide removal and precise surface cleaning.
2Productivity
If the size of through holes is reduced to accommodate smaller semiconductor components, then component density increases, but byproduct deposition in the through holes becomes more severe
Solution Approach 1:
The patent replaces the purely mechanical/physical bombardment approach with a chemical-based cleaning process for the second step. The fluorine-based chemistry selectively reacts with and removes byproducts through chemical reactions rather than physical sputtering, enabling effective cleaning of sub-100nm through holes where physical methods fail.
Solution Approach 2:
The patent changes the fundamental parameter of the cleaning mechanism from physical (argon ion bombardment) to chemical (fluorine-based reactions). This parameter change allows the process to effectively clean smaller features by using chemical selectivity and lower momentum transfer that doesn't cause the same byproduct deposition issues.
3Manufacturing precision
If a chemical cleaning process is used to remove byproducts, then byproduct removal is effective, but additional process steps are required
Solution Approach 1:
The patent merges two distinct cleaning mechanisms (physical bombardment and chemical cleaning) into a unified cleaning sequence that addresses both bulk oxide removal and byproduct elimination. By combining these approaches in a coordinated manner, the process achieves comprehensive cleaning that neither method could accomplish alone, justifying the additional step through superior overall performance.
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 method effectively prevents byproduct deposition, reduces resistance, and maintains the integrity of small features by ensuring smooth side walls and complete oxide removal at the bottom of contact through holes, thereby enhancing semiconductor component performance.
Implementation Method 1
a physical cleaning process. The physical cleaning process includes a step of introducing a first reacting gas including argon so as to partially remove an oxide generated in the semiconductor process and located at a bottom of the contact through hole
Implementation Method 2
a chemical cleaning process. The chemical cleaning process utilizes a second reacting gas comprising ammonia and nitrogen trifluoride
Implementation Method 3
the byproduct is removed by applying a thermal process to the semiconductor component. the byproduct is removed at a sublimation temperature
Data Source
AI summary
A cleaning method of a semiconductor manufacturing process is provided. The cleaning method is applied to a semiconductor component including a plurality of material layers formed thereon. An opening is defined in the material layers, and a side wall is exposed from the opening. The side wall at least includes a first material layer and a second material layer. At first, a first cleaning process is performed till a lateral etched thickness of the first material layer is equal to a lateral etched thickness of the second material layer. Then, a byproduct formed in the first cleaning process is removed.