Contact Plug Oxide Reduction for Low-Resistance Interconnects
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the formation of oxidized portions in contact plugs during the fabrication process, which leads to high resistance and poor conductivity between the contact plugs and upper-level interconnects, complicating the formation of low-resistance conducting routes.
Innovation Solution
A pre-deposition treatment using a gas mixture of NH3 and N2 is applied to reduce oxidized portions of the contact plugs to a metal state, preventing the formation of nitride and ensuring subsequent upper-level interconnects are in direct contact with metal portions, thereby maintaining low resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact plugs are formed during fabrication, then electrical connection is established, but oxidized portions form on the contact plug surface increasing resistance
Solution Approach 1:
A pre-deposition treatment is performed before depositing the upper-level interconnect to reduce oxidized portions of the contact plug. This preliminary action removes the harmful oxide layer that would otherwise increase resistance and degrade conductivity, ensuring low-resistance electrical connection is maintained.
Solution Approach 2:
The oxidation process, which initially creates harmful oxide layers on the contact plug, is converted into a benefit through the pre-deposition treatment. The treatment selectively reduces the oxide portions, and the resulting structure with controlled oxide removal actually improves conductivity by eliminating the high-resistance barrier while the treatment process itself can be optimized to prevent excessive nitride formation.
2Reliability
If pre-deposition treatment is applied to reduce oxide, then conductivity is improved, but nitride formation may occur
Solution Approach 1:
The pre-deposition treatment parameters (temperature, pressure, gas composition, treatment duration) are carefully controlled and optimized to achieve selective reduction of oxide portions while preventing nitride formation. By adjusting these parameters, the treatment creates favorable conditions for oxide removal without causing harmful side reactions that would form nitride layers.
Solution Approach 2:
The pre-deposition treatment is applied with selective characteristics, affecting different portions of the contact plug differently. The treatment specifically targets and reduces oxidized portions while leaving other areas unaffected, and with proper parameter control, prevents nitride formation in vulnerable regions. This localized effect ensures conductivity improvement without introducing new harmful factors.
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 method effectively converts oxidized portions of contact plugs to metal, ensuring low-resistance conducting routes and reducing the formation of nitride, thus enhancing the conductivity and reliability of semiconductor devices.
Implementation Method 1
A pre-deposition treatment is performed before depositing the upper-level interconnect. The pre-deposition treatment may reduce oxidized portions of the contact plug to a metal state
Data Source
AI summary
A method of forming a semiconductor device includes forming an electronic component over a substrate; forming a first insulating layer over the electronic component; forming a contact plug extending through the first insulating layer to the electronic component, wherein the contact plug includes a first portion formed of a conductive material and a second portion formed of an oxide of the conductive material disposed over the first portion; performing a treatment to expose the contact plug and the first insulating layer to a gas mixture of N2 and NH3; after performing the treatment, forming a second insulating layer over the contact plug and the first insulating layer; and forming an interconnect in the second insulating layer and in contact with the contact plug.