Fin-Type IC Manufacturing Using Diffusion Buffer Layer
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Solution Overview
Problem
The challenge in manufacturing integrated circuit devices with fine critical dimensions is maintaining dimensional accuracy and electrical characteristics, particularly due to the limitations of photolithography and the risk of damage during etching processes for multiple-layer patterning.
Innovation Solution
A method involving the formation of fin-type active regions with a diffusion buffer layer to block oxygen diffusion, followed by the creation of carbon-containing mask patterns for precise ion implantation, which helps in preventing oxidation and damage during etching, ensuring stable profiles and accurate dimensional control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If photolithography is used to form fine patterns with reduced design rule, then the critical dimension is reduced, but the dimensional accuracy of patterns cannot be guaranteed
Solution Approach 1:
The patent divides the patterning process into multiple stages using a multi-layer mask structure. Instead of relying on a single photolithography step, the process segments the pattern formation into: (1) forming a first mask layer with initial patterns, (2) forming a second mask layer with refined patterns, and (3) using these layered masks to define the final fine patterns. This segmentation allows each layer to contribute to the overall dimensional accuracy, overcoming the resolution limits of single-step photolithography.
Solution Approach 2:
The patent transitions from two-dimensional planar patterning to three-dimensional multi-layer mask structures. By stacking multiple mask layers vertically and using selective etching through these layers, the process achieves fine critical dimensions that cannot be obtained with conventional single-layer photolithography. The vertical dimension provides additional degrees of freedom for controlling pattern dimensions and accuracy.
2Manufacturing precision
If multiple-layer mask pattern is used during photolithography, then the resolution limit is overcome, but lower structures are damaged during etching processes
Solution Approach 1:
The patent introduces a protective film as an intermediary layer between the mask structures and the underlying fin-type active regions. This protective film serves as a buffer that prevents direct contact between etching gases and the sensitive lower structures during mask formation. The film is selectively removed only in areas where pattern transfer is intended, thereby protecting lower structures from damage while allowing precise pattern definition.
Solution Approach 2:
The protective film is formed in advance before any etching processes begin. This preliminary protective layer is deposited conformally over the entire surface, including over the fin-type active regions, before mask layers are applied. By establishing this protection beforehand, the process ensures that subsequent etching steps cannot damage the lower structures, as the protective film acts as a barrier that must be selectively removed first.
3Productivity
If oxygen is present during etching processes, then the etching can proceed, but oxidation of fin-type active regions occurs
Solution Approach 1:
The protective film acts as an intermediary barrier that physically separates oxygen-containing etching environments from the fin-type active regions. During etching processes that require oxygen-containing gases, the protective film prevents oxygen from reaching and oxidizing the sensitive semiconductor structures. The film allows the etching to proceed in the desired areas while blocking oxidation in protected areas, thereby maintaining compositional stability.
Solution Approach 2:
The protective film creates a localized inert environment over the fin-type active regions by preventing oxygen diffusion. Even when the overall chamber atmosphere contains oxygen for etching purposes, the protective film establishes an oxygen-excluded zone directly over the sensitive structures. This inert barrier effect maintains the chemical stability of the fin-type active regions without requiring the entire process environment to be oxygen-free.
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 enhances the precision of dimensional control and electrical characteristics of integrated circuit devices by preventing oxidation and damage during the etching process, maintaining the stability of fin-type active regions and achieving desired critical dimensions.
Implementation Method 1
A diffusion buffer layer is formed on the fin-type active regions to block oxygen from diffusing into the fin-type active regions
Implementation Method 2
A carbon-containing mask pattern is formed to have an opening exposing a portion of the diffusion buffer layer by etching the carbon-containing layer using an etching gas including an oxygen atom
Implementation Method 3
Impurity ions are implanted into a subset of the fin-type active regions through the opening and the diffusion buffer layer using the carbon-containing mask pattern as an ion-implantation mask
Data Source
AI summary
To manufacture an integrated circuit device, a diffusion buffer layer and a carbon-containing layer are sequentially formed on a plurality of fin-type active regions formed in a substrate. A carbon-containing mask pattern is formed to have an opening exposing a portion of the diffusion buffer layer by etching the carbon-containing layer using an etching gas including an oxygen atom while the diffusion buffer layer is blocking oxygen from diffusing into the fin-type active regions. Impurity ions are implanted into some fin-type active regions through the opening and the diffusion buffer layer using the carbon-containing mask pattern as an ion-implantation mask, the some fin-type active regions being selected from among the plurality of fin-type active regions.