Semiconductor Conductive Layer Void Elimination via Reflow and Electroplating
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, affecting production efficiency and costs.
Innovation Solution
A method for forming a conductive structure in a semiconductor device involves depositing a first conductive material layer, performing a reflow process to eliminate voids, and then using electroplating or electroless plating to form a second conductive layer that fills narrow recesses in the dielectric layer, ensuring reliable interconnects and improved yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to form conductive layers in narrow recesses, then the process is simple, but voids form and filling is incomplete
Solution Approach 1:
The conductive layer formation is divided into multiple sequential steps: initial deposition of conductive material, reflow processing to reshape, and electroplating to complete filling. This segmentation allows each step to address specific requirements - the initial layer provides nucleation sites, reflow creates a concave meniscus shape, and electroplating completes the filling - thereby achieving complete void-free filling while managing process complexity through structured multi-step methodology
Solution Approach 2:
The invention changes the physical and chemical parameters of the conductive material layer during processing. The reflow process alters the temperature and surface tension parameters to reshape the material into a concave meniscus configuration. Subsequently, electroplating parameters (current density, electrolyte composition, time) are optimized to achieve uniform filling. These parameter transformations enable complete filling of narrow recesses that cannot be achieved by conventional single-step deposition
2Productivity
If feature sizes are reduced to increase functional density, then production efficiency increases, but fabrication difficulty increases
Solution Approach 1:
The invention introduces intermediary processing steps between conventional deposition and final filling. The reflow process acts as an intermediary that transforms the initially deposited material into a optimized configuration with a concave meniscus shape, creating ideal conditions for subsequent electroplating. This intermediary transformation enables reliable filling at reduced feature sizes by preparing the substrate and material in a specific intermediate state that facilitates complete filling
Solution Approach 2:
The initial deposition of conductive material layer and the reflow processing are performed as preliminary actions before the main electroplating filling step. These preliminary steps prepare the narrow recesses by creating a nucleation layer and establishing the correct meniscus shape, ensuring that when electroplating occurs, the material flows in uniformly and completely fills the recess without voids. This preliminary preparation is critical for maintaining fabrication ease at smaller feature sizes
3Reliability
If electroplating is used to fill narrow recesses, then complete filling is achieved, but process complexity increases
Solution Approach 1:
The invention applies different processing methods to different regions and stages of the filling process. The initial deposition targets the entire surface uniformly, the reflow process locally reshapes material at the recess openings to create concave menisci, and electroplating specifically targets the narrow recess interiors. This local quality approach - applying appropriate methods to appropriate locations and stages - achieves reliable complete filling while managing overall process complexity through targeted rather than universal processing
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 enhances the reliability and efficiency of forming conductive structures within tight spaces, improving the yield and reliability of semiconductor devices by eliminating voids and ensuring proper filling of recesses, even at nanoscale dimensions.
Implementation Method 1
performing a reflow process to convert the first conductive material layer into a first conductive layer
Implementation Method 2
performing an electroplating process to form a second conductive layer over the first conductive layer so as to fill the narrow recess
Data Source
AI summary
A method for forming a semiconductor device structure is provided. The method includes forming a dielectric layer over a semiconductor substrate. The dielectric layer has a first recess. The method includes forming a first conductive material layer over an inner wall and a bottom of the first recess. The first conductive material layer is partially filled in the first recess. The method includes performing a reflow process to convert the first conductive material layer into a first conductive layer. The first conductive layer has a second recess in the first recess. The method includes performing an electroplating process or an electroless plating process to form a second conductive layer over the first conductive layer so as to fill the second recess.