Cluster Ion Implantation for Semiconductor Epitaxial Wafer Gettering
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Solution Overview
Problem
Existing methods for producing semiconductor epitaxial wafers using single-ion implantation fail to sufficiently reduce white spot defects and require lengthy high-temperature recovery heat treatments, which hinder throughput and gettering capability.
Innovation Solution
Irradiating semiconductor wafers with cluster ions to form a modifying layer with a high concentration of constituent elements, such as carbon, near the surface, allowing for the formation of an epitaxial layer without separate recovery heat treatment, thereby enhancing gettering capability and reducing crystal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single-ion implantation is used to form gettering sites, then metal contamination is reduced to some extent, but white spot defects are not sufficiently reduced and gettering capability is insufficient
Solution Approach 1:
The patent changes the ion implantation parameters by using cluster ions instead of single ions, with specific cluster sizes (10-100 atoms) and controlled implantation doses (1×10^14 to 1×10^16 ions/cm²). This parameter change creates a modifying layer with higher peak concentration of gettering elements, significantly improving metal contamination suppression and reducing white spot defects
Solution Approach 2:
The patent creates a composite modifying layer by implanting cluster ions containing multiple elements (e.g., carbon, silicon, oxygen) into the semiconductor wafer. This composite structure enhances gettering capability through synergistic effects of different elements, providing superior metal contamination suppression compared to single-element implantation
2Reliability
If single-ion implantation is performed, then gettering sites are formed, but crystal damage occurs requiring lengthy high-temperature recovery heat treatment
Solution Approach 1:
The patent changes the implantation method from single ions to cluster ions, which reduces crystal damage despite achieving the same or higher gettering effect. The cluster structure distributes energy more effectively, minimizing lattice disruption. This allows elimination of separate recovery heat treatment or reduces it to brief annealing (10-60 seconds at 900-1100°C), dramatically reducing process time
Solution Approach 2:
The patent extracts the recovery heat treatment step from the conventional process by using cluster ion implantation that causes minimal crystal damage. The modifying layer formed by cluster ions is sufficiently stable without requiring extensive thermal recovery, thereby removing or minimizing this time-consuming step
3Reliability
If cluster ions are used instead of single ions, then gettering capability is enhanced and crystal damage is reduced, but new process conditions and parameters must be controlled
Solution Approach 1:
The patent establishes specific parameter ranges for cluster ion implantation: cluster size (10-100 atoms), implantation dose (1×10^14 to 1×10^16 ions/cm²), and acceleration energy (1-100 keV/atom). These controlled parameters ensure optimal modifying layer formation with peak concentration at appropriate depths while minimizing crystal damage, balancing enhanced gettering capability with manageable process complexity
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 improves gettering capability, reduces crystal damage, and eliminates the need for lengthy recovery heat treatments, leading to more efficient production of semiconductor epitaxial wafers with reduced white spot defects in solid-state image sensing devices.
Implementation Method 1
irradiating a semiconductor wafer with cluster ions to form a modifying layer formed from a constituent element of the cluster ions in a surface portion of the semiconductor wafer
Data Source
AI summary
The present invention provides a method of more efficiently producing a semiconductor epitaxial wafer, which can suppress metal contamination by achieving higher gettering capability.A method of producing a semiconductor epitaxial wafer 100 according to the present invention includes a first step of irradiating a semiconductor wafer 10 with cluster ions 16 to form a modifying layer 18 formed from a constituent element of the cluster ions 16 in a surface portion 10A of the semiconductor wafer; and a second step of forming an epitaxial layer 20 on the modifying layer 18 of the semiconductor wafer 10.