Hollow Isolating Trenches Fabrication via Segmented Filling
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Solution Overview
Problem
Conventional methods for producing integrated circuits with hollow isolating trenches result in narrow trenches with reduced air volume, limiting the dimensions and leading to electrostatic coupling and mechanical strain issues.
Innovation Solution
A two-phase method for fabricating integrated circuits where trenches are first filled with a removable material and then accessed and plugged after active component production, allowing for wider trenches with a large air volume and reduced electrostatic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the trench opening is made narrow to enable complete plugging, then the plugging operation is effective, but the air volume in the trench is reduced
Solution Approach 1:
The process is divided into two phases: first forming and filling the trench, then after active device fabrication, creating openings through the encapsulation layer to access and empty the trenches. This segmentation allows the trench to be initially wide for large air volume while enabling effective plugging in the second phase after the fill material is removed.
Solution Approach 2:
The trench is filled with a fill material in advance during the initial phase, which allows the trench opening to be wider than it would be in conventional methods. The fill material is then removed through openings created after encapsulation, enabling effective plugging without compromising the initial air volume.
2Object-affected harmful factors
If wide trenches are produced to increase air volume, then electrostatic coupling is reduced, but conventional plugging methods cannot be used
Solution Approach 1:
The manufacturing process is segmented into two distinct phases: initial trench formation and filling, followed by a second phase where openings are created through the encapsulation layer to access the trenches for emptying and plugging. This allows wide trenches to be created without compromising plugging feasibility.
Solution Approach 2:
The trenches are filled with a removable fill material in advance, which serves as a placeholder that allows wide trench dimensions. The fill material is then removed through openings created after active device fabrication, enabling conventional plugging methods to be used on wide trenches.
3Productivity
If trenches are produced before active devices, then the fabrication sequence is conventional, but the trenches must be narrow for effective plugging
Solution Approach 1:
The fabrication process is divided into two phases: initial trench formation and filling before active device fabrication, followed by a second phase after encapsulation where openings are created to access and empty the trenches. This maintains conventional fabrication sequencing while enabling large air volume.
Solution Approach 2:
The trenches are filled with a removable fill material in advance during the initial phase, allowing wide trench dimensions for large air volume. The fill material is then removed through openings created after encapsulation, enabling effective plugging without compromising the initial air volume.
4Manufacturing precision
If the trench opening is plugged conformally, then the plugging is complete, but narrow trenches are required to avoid over-filling
Solution Approach 1:
The process is divided into two phases: initial trench formation and filling, then after active device fabrication and encapsulation, creating openings through the encapsulation layer to access and empty the trenches before plugging. This allows conformal plugging on wide trenches without over-filling issues.
Solution Approach 2:
The trenches are filled with a removable fill material in advance, which is then removed through openings created after encapsulation. This preliminary removal of fill material allows conformal plugging to be applied to wide trenches without the risk of over-filling, as the openings provide direct access to the trench interior.
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
Enables the creation of integrated circuits with hollow isolating trenches of desired dimensions, reducing electrostatic coupling and mechanical strain, while maintaining a large air volume and allowing for conventional gate and contact production methods.
Implementation Method 1
The etching of the fill material 4 is carried out by means of a chemical etch
Implementation Method 2
The plugging of the opening 2a of the trench 2 comprises a physical vapor deposition of a plugging material 9
Data Source
AI summary
A method is provided for fabricating an integrated circuit. According to the method, hollow isolating trenches are produced within a substrate, and active components are produced in and on active areas of the substrate that are between the trenches. The trenches are produced in an initial phase carried out before production of the active components and a final phase carried out after production of the active components. In the initial phase, trenches are formed in the substrate, and the trenches are filled with a fill material. In the final phase, the active components are encapsulated, accesses are created through the encapsulation material to each filled trench, the fill material is removed through each access, and the opening of each trench is plugged through the corresponding access. Also provided is an integrated that includes hollow isolating trenches within a substrate.