Transistor Contact Structure for Dielectric Etch Damage Control
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Solution Overview
Problem
As semiconductor devices continue to shrink in size, challenges arise in maintaining electrical isolation and reducing damage to dielectric materials during the etching process for forming contacts and vias, which affects the integration density and performance of electronic components.
Innovation Solution
A method is introduced to reduce the etch rate of dielectric materials around openings by performing treatment processes, thereby minimizing damage and enhancing electrical isolation, using techniques such as chemical vapor deposition and etch stop layers to protect the dielectric material during cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the minimum feature size is reduced to improve integration density, then more components can be integrated into a given area, but damage to dielectric materials during etching increases and electrical isolation deteriorates
Solution Approach 1:
The patent applies preliminary action by performing a treatment process on the dielectric material before the etching process. This treatment modifies the dielectric material in advance to reduce its etch rate, thereby protecting it from damage during subsequent etching operations. The treatment is applied selectively to regions that will be affected by etching, preparing them beforehand to resist the harmful effects of the etching process while allowing the etching to proceed for contact and via formation.
2Productivity
If aggressive etching is used to clean openings efficiently, then productivity increases, but damage to dielectric materials worsens and electrical isolation ability deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform etch rate distribution within the dielectric material. The treatment process modifies specific regions of the dielectric material to have different etch rates - regions near openings have reduced etch rates to protect them from damage, while other regions maintain their original etch rates. This spatial variation in etch rate allows selective protection of critical areas during etching, maintaining electrical isolation ability in treated regions while allowing efficient cleaning in untreated regions.
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 the electrical isolation ability of dielectric materials, reducing damage and enhancing the integration density and performance of semiconductor devices by maintaining the integrity of the dielectric layers during the manufacturing process.
Implementation Method 1
One or more treatment process(es) are performed to decrease an etch rate of the dielectric material around the opening, relative an etching process that will be used to clean the opening
Implementation Method 2
using techniques such as chemical vapor deposition and etch stop layers to protect the dielectric material during cleaning
Data Source
AI summary
In an embodiment, a device includes: a source/drain region over a semiconductor substrate; a dielectric layer over the source/drain region, the dielectric layer including a first dielectric material; an inter-layer dielectric over the dielectric layer, the inter-layer dielectric including a second dielectric material and an impurity, the second dielectric material different from the first dielectric material, a first portion of the inter-layer dielectric having a first concentration of the impurity, a second portion of the inter-layer dielectric having a second concentration of the impurity, the first concentration less than the second concentration; and a source/drain contact extending through the inter-layer dielectric and the dielectric layer to contact the source/drain region, the first portion of the inter-layer dielectric disposed between the source/drain contact and the second portion of the inter-layer dielectric.