Semiconductor Die Sodium Stopper for Leakage Current Reliability
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Solution Overview
Problem
Sodium diffusion during the assembly process can create parasitic n-channel devices in p-channel semiconductor devices, leading to increased leakage currents during high temperature reverse bias and high humidity high temperature reverse bias tests, which are critical for the reliability of p-channel devices.
Innovation Solution
A sodium stopper groove filled with a diffusion barrier material is integrated into the insulation layer around the active region of the semiconductor die, preventing sodium diffusion and thereby protecting the p-channel device from parasitic n-channel formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a p-channel device is used in the active region, then the device can operate with standard doping configurations, but sodium diffusion can create parasitic n-channel devices leading to increased leakage currents
Solution Approach 1:
A sodium stopper structure is introduced as an intermediary element between the insulation layer and the active region. This stopper comprises a sodium stopper groove filled with a diffusion barrier material (such as silicon nitride or silicon oxide), which acts as a mediator to block sodium ions from diffusing into the active region and creating parasitic devices, thereby resolving the contradiction between maintaining standard device operation and preventing sodium-induced reliability issues
2Reliability
If the insulation layer is continuous without interruptions, then the insulation is complete, but sodium can diffuse laterally through the insulation layer towards the active region
Solution Approach 1:
The continuous insulation layer is segmented by introducing a sodium stopper groove that vertically intersects it. This segmentation creates a discontinuity in the insulation layer at the location of the stopper, allowing the diffusion barrier material to be inserted. The groove is positioned such that it does not compromise the overall insulation function while effectively blocking sodium diffusion paths, thus resolving the contradiction between maintaining insulation integrity and preventing sodium diffusion
3Ease of manufacture
If no sodium stopper is provided, then the manufacturing process is simpler, but parasitic n-channel devices form due to sodium diffusion causing increased leakage currents during HTRB and H3TRB tests
Solution Approach 1:
The sodium stopper groove and diffusion barrier material are integrated into the manufacturing process at an early stage, specifically after forming the insulation layer and before completing the metallization layers. This preliminary action ensures that the barrier is in place before sodium contamination can occur during subsequent assembly processes such as die attach, preventing parasitic device formation without significantly complicating the overall manufacturing flow
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 sodium stopper effectively reduces the formation of parasitic devices, minimizing leakage currents and enhancing the reliability of p-channel devices under stress test conditions.
Implementation Method 1
the diffusion barrier material prevents a sodium diffusion in the insulation layer, e. g. from a lateral edge of the die towards the active region
Data Source
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AI summary
The disclosure relates to a semiconductor die (1), having a semiconductor body (2) comprising an active region (3),an insulation layer (4) formed on the semiconductor body (2), wherein a p-channel device (5) is formed in the active region (3), and wherein a sodium stopper (10) is formed in the insulation layer (4) and arranged laterally between the active region (3) and a lateral edge (1.1) of the die (1), the sodium stopper (10) comprising an insulation layer groove (11), which intersects the insulation layer (4) vertically and extends around the active region (3), the insulation layer groove (11) filled with a diffusion barrier material (21).