Ring-Type Trench Capacitor Surface Area Scaling
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Solution Overview
Problem
The existing methods for forming capacitor trenches in semiconductor devices are complex and time-consuming, leading to reduced capacitance due to decreased contact area between the capacitor dielectric layer and the electrode, as the size of the capacitor trench is scaled down.
Innovation Solution
A method involving a ring-type capacitor structure is developed using a lithographic apparatus with specific photomask patterns to form a ring-type trench, enhancing the surface area and capacitance by forming a patterned mask layer, creating a ring-type trench with inner and outer walls, and constructing a capacitor structure within this trench.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of capacitor trench is scaled down, then the device size is reduced, but the contact area between capacitor dielectric layer and electrode decreases leading to reduced capacitance
Solution Approach 1:
The patent transitions from a conventional planar capacitor structure to a ring-type trench structure with vertical walls. This dimensional change allows the capacitor to utilize both the bottom surface and the inner wall surfaces for electrode contact, effectively increasing the contact area within a smaller footprint. The ring-type structure creates additional surface area through its vertical inner and outer walls, solving the problem of reduced contact area during device scaling.
2Reliability
If the conventional method of forming capacitor trench is used, then the capacitor structure can be formed, but the manufacturing process becomes complicated and time-consuming
Solution Approach 1:
The patent combines multiple process steps into fewer operations. Specifically, it merges the mask formation and trench etching into a single lithographic step using a patterned mask layer, and combines the electrode formation and dielectric layer deposition into an integrated sequence. This reduces the total number of manufacturing steps while maintaining the reliability of capacitor structure formation, directly addressing the complexity issue.
3Reliability
If the conventional method with multiple steps is used, then the capacitor trench can be formed, but the manufacturing time increases
Solution Approach 1:
The patent performs preliminary actions by pre-forming a patterned mask layer that defines the ring-type trench geometry before trench etching. This preliminary patterning step enables subsequent process steps to proceed more efficiently and with better precision. The pre-established pattern guide allows for streamlined manufacturing while ensuring reliable capacitor trench formation, thereby improving productivity without sacrificing quality.
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 increases the surface area and capacitance of the capacitor without additional costs in lithographic equipment, facilitating the scaling of semiconductor devices while simplifying the manufacturing process.
Implementation Method 1
utilizes two lithographic steps to improve the resolution of the ring-type pattern and enhances the profile of the ring-type capacitor as well as facilitating the scaling of the capacitor
Implementation Method 2
providing a first photomask having a first feature pattern to define the outer wall; exposing the negative-type photoresist layer with the first photomask; providing a second photomask having a second feature pattern to define the inner wall; exposing the negative-type photoresist layer with the second photomask; and developing the negative-type photoresist layer
Data Source
AI summary
A method of forming a ring-type capacitor is provided. The method includes providing a substrate; forming a patterned mask layer on the substrate, the patterned mask layer defining a ring pattern; removing the substrate by using the patterned mask layer as a mask to form a ring-type trench in the substrate; the ring-type trench including an inner wall and an outer wall; and forming a capacitor structure on the inner wall and the outer wall of the ring-type trench.