Copper-Manganese Sputtering Target Machinability and Diffusion Control
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Solution Overview
Problem
Conventional copper wiring materials for semiconductors face challenges in machinability, leading to surface irregularities and particle generation during sputtering, which affect the uniformity and reliability of thin films, especially as semiconductor products miniaturize and integrate.
Innovation Solution
A high purity copper-manganese alloy sputtering target is developed with controlled Mn content (0.05-20 wt%) and additive elements (Ca, P, Si, S) within specific ranges to enhance machinability, surface smoothness, and prevent self-diffusion, thereby improving the workability and reliability of semiconductor products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional copper wiring material is used, then electrical conductivity is improved, but machinability deteriorates leading to surface irregularities and particle generation
Solution Approach 1:
The patent changes the chemical composition parameters by adding Mn (0.05-20 wt%) and controlling additive elements (Ca, P, Si, S) within specific ranges. This parameter modification improves machinability while maintaining electrical conductivity, resolving the contradiction between reliability and ease of manufacture
Solution Approach 2:
The patent creates a composite alloy material by combining Cu with Mn and controlled amounts of additive elements. This composite structure achieves both good machinability and electrical conductivity, simultaneously satisfying both requirements that were previously contradictory
2Reliability
If copper is used as wiring material, then electrical conductivity is improved, but self-diffusion suppression deteriorates causing contamination of Si substrate and insulator film
Solution Approach 1:
The patent introduces Mn as an intermediary element that forms a barrier layer between Cu and the Si substrate/insulator film. This intermediary layer suppresses Cu diffusion and contamination while allowing the Cu wiring to maintain its electrical conductivity function
Solution Approach 2:
By creating a Cu-Mn composite alloy with controlled additive elements, the patent achieves both high electrical conductivity and effective self-diffusion suppression, resolving the contradiction between these two properties
3Ease of operation
If target material is cut and processed, then workability is improved, but surface smoothness deteriorates affecting thin film uniformity
Solution Approach 1:
The patent modifies the material parameters by adding Mn and controlling additive elements, which changes the physical properties of the target material to improve machinability. This allows cutting and processing while maintaining surface smoothness, resolving the contradiction between workability and manufacturing precision
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 copper-manganese alloy target improves machinability, reduces particle generation during sputtering, and provides superior self-diffusion suppression, electromigration resistance, and corrosion resistance, enhancing the yield and reliability of semiconductor products.
Implementation Method 1
the method of forming a diffusion barrier layer made of Ta or TaN on a wiring or a wiring groove, and thereafter subjecting copper to sputter deposition
Implementation Method 2
reacting the Mn in the Cu-Mn alloy with the oxygen of the insulator film to self-form a barrier layer
Implementation Method 3
copper itself is an extremely active metal and diffuses easily, and there is a problem in that copper contaminates the Si substrate or its periphery
Data Source
AI summary
A high purity copper-manganese alloy sputtering target containing 0.05 to 20 wt% of Mn and, excluding additive elements, remainder being Cu and unavoidable impurities, wherein the target contains 0.001 to 0.06 wtppm of P and 0.005 to 5 wtppm of S, and further contains Ca and Si, and a total content of P, S, Ca, and Si is 0.01 to 20 wtppm. The incorporation of appropriate amounts of Mn as well as Ca, P, Si, and S in copper improves the machinability that is required in the stage of producing a target to facilitate the manufacture (workability) of the target, improves the smoothness of the target surface, and inhibits the generation of particles during sputtering. Thus, provided is a high purity copper-manganese alloy sputtering target which is particularly useful for improving the yield and reliability of semiconductor products that progress toward miniaturization and integration.