Through Silicon Via Diffusion Barrier for Copper Resistance
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Solution Overview
Problem
Current 3D semiconductor memory devices face challenges in maintaining low electrical resistance and preventing dopant out-diffusion during thermal processes, as copper conductive materials degrade and polysilicon dopants diffuse into the main device, altering electrical characteristics.
Innovation Solution
A semiconductor device with a through silicon via structure that includes a conductive plug, a first insulation layer, and a diffusion barrier layer, where the diffusion barrier layer is formed by reacting a metal layer with a silicon-containing conductive material to create a metal silicide layer, preventing dopant out-diffusion and reducing total resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used as conductive material in through silicon via, then electrical resistance is reduced, but copper degrades during high temperature thermal processes and cannot maintain low resistance
Solution Approach 1:
A diffusion barrier layer is introduced as an intermediary between the copper conductive material and the surrounding insulation layer. This barrier layer prevents direct interaction between copper and the insulation materials during thermal processes, thereby maintaining low electrical resistance while withstanding high temperatures.
Solution Approach 2:
The through silicon via structure uses a composite material system consisting of copper core with a surrounding diffusion barrier layer. This composite structure combines the low resistance property of copper with the thermal stability of the barrier layer, resolving the contradiction between electrical performance and thermal resistance.
2Temperature
If polysilicon is used as conductive material to withstand high temperature thermal processes, then thermal stability is improved, but dopants diffuse from polysilicon into the main device altering electrical characteristics
Solution Approach 1:
The diffusion barrier layer serves as an intermediary that blocks dopant diffusion from the polysilicon conductive material into the main device. This allows the use of polysilicon for its thermal stability while preventing the harmful dopant out-diffusion that would otherwise alter the electrical characteristics of surrounding devices.
3Productivity
If via-first process is used to form through silicon holes and fill with conductive material, then integration density is improved, but dopant out-diffusion during subsequent thermal processes alters main device characteristics
Solution Approach 1:
The diffusion barrier layer is formed preliminarily around the conductive material before any thermal processes are performed. This preliminary protective action prevents dopant out-diffusion during subsequent high-temperature processing steps, allowing the via-first process to achieve high integration density without compromising main device characteristics.
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 solution effectively prevents dopant out-diffusion and reduces the total resistance of the through silicon via, maintaining stable electrical characteristics and improving integration capabilities beyond 2D structures.
Implementation Method 1
performing a thermal process to make portions of the metal layer react with the silicon-containing conductive material to form a diffusion barrier layer
Data Source
AI summary
The present disclosure relates to a semiconductor device and a method of manufacturing the same. The semiconductor device includes a semiconductor substrate and at least one through silicon via. The through silicon via includes a conductive plug, a first insulation layer, and a diffusion barrier layer. The conductive plug penetrates through the semiconductor substrate. The first insulation layer surrounds the conductive plug. The diffusion barrier layer is disposed between the conductive plug and the first insulation layer, and is utilized to prevent out-diffusion of dopant impurities from the conductive plug to the semiconductor substrate.