Tungsten Connection Structure CMP Defect Reduction via Fluorine-Rich Interfacial Layer
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Solution Overview
Problem
The manufacturing process of semiconductor integrated circuits faces challenges due to the influence of pre-layer distribution on the size and density of components, leading to yield loss and requiring modifications in manufacturing processes and structural design.
Innovation Solution
A nitrogen-containing treatment is applied to the tungsten nucleation layer, forming an interfacial layer with a higher fluorine concentration between the tungsten nucleation and filling layers, which is then removed through a chemical mechanical polishing process to improve the CMP process and reduce yield loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional tungsten nucleation layer and tungsten filling layer structure is used, then the connection structure can be formed, but the CMP process produces defects and results in yield loss
Solution Approach 1:
An interfacial layer is introduced between the tungsten nucleation layer and the tungsten filling layer to serve as a mediator that improves CMP process uniformity and reduces defects. The interfacial layer, having different material properties than the adjacent tungsten layers, acts as a buffer zone that enhances polishing control and prevents direct interaction between the nucleation and filling layers during CMP, thereby improving both manufacturing precision and yield.
Solution Approach 2:
The interfacial layer is specifically positioned at the interface region between the nucleation and filling layers, providing localized improvement in CMP performance. This local modification allows the bulk properties of the tungsten layers to remain unchanged while addressing the specific CMP defects that occur at the interface region, thus improving manufacturing precision without affecting the overall structural integrity.
2Manufacturing precision
If the interfacial layer is formed with higher fluorine concentration, then the CMP process uniformity is improved, but additional process steps are required
Solution Approach 1:
The formation of the interfacial layer with higher fluorine concentration is merged with the existing tungsten deposition process. By controlling the deposition conditions and precursor delivery, the interfacial layer is formed in-situ during the tungsten filling process, eliminating the need for separate deposition steps while achieving the desired fluorine concentration gradient and improving CMP uniformity.
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 interfacial layer with higher fluorine concentration enhances the polishing resistance and reduces defects, thereby improving the manufacturing yield and reducing yield loss in the formation of connection structures.
Implementation Method 1
A deposition process is performed to form a tungsten filling layer on the tungsten nucleation layer. An interfacial layer is formed between the tungsten nucleation layer and the tungsten filling layer by the deposition process.
Implementation Method 2
A chemical mechanical polishing (CMP) process is performed to remove a part of the tungsten nucleation layer and a part of the tungsten filling layer for forming connection structures in the openings.
Data Source
AI summary
A manufacturing method of a connection structure includes the following steps. A dielectric layer is formed on conductive structures. Openings are formed in the dielectric layer and expose the conductive structures. A tungsten nucleation layer is conformally formed on the dielectric layer and in the openings. A nitrogen-containing treatment is performed on the tungsten nucleation layer. A deposition process is performed to form a tungsten filling layer on the tungsten nucleation layer. An interfacial layer is formed between the tungsten nucleation layer and the tungsten filling layer by the deposition process. A fluorine concentration of the interfacial layer is higher than that of the tungsten filling layer. A chemical mechanical polishing (CMP) process is performed to remove a part of the tungsten nucleation layer and a part of the tungsten filling layer for forming connection structures. The interfacial layer is removed by the CMP process.