High Aspect Ratio Trench Burying via Electron Beam Induced Deposition
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Solution Overview
Problem
Existing methods for burying trenches in samples with high aspect ratios face challenges such as laborious resin application, uneven chemical vapor deposition, and the formation of cavities, making it difficult to achieve uniform filling without material incompatibility issues.
Innovation Solution
A method involving cutting a sample piece with trenches and irradiating an electron beam to generate secondary electrons, which decompose injected compound gases for uniform deposition within the trenches, ensuring even filling without cavity formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If resin or ink is applied to bury trenches, then the trenches can be filled with a buried material, but the process becomes laborious and time consuming due to penetration, drying, and material incompatibility issues
Solution Approach 1:
The patent replaces the mechanical application method (brushing, dipping, or spraying resin/ink) with a chemical vapor deposition process using compound gas. The compound gas decomposes under electron beam irradiation to deposit the buried material directly into the trenches, eliminating the need for manual application and drying steps.
Solution Approach 2:
The patent changes the state of the buried material from liquid (resin/ink) to gaseous form (compound gas). This parameter change allows the material to penetrate deep trenches uniformly and deposit through thermal decomposition, avoiding the time-consuming penetration and drying steps of liquid applications.
2Extent of automation
If chemical vapor deposition is used to bury high aspect ratio trenches, then automation is improved, but cavities form in the trenches due to overhang formation near openings
Solution Approach 1:
The patent inverts the conventional CVD approach by irradiating the electron beam from the side surface of the sample rather than from the opening side. This causes the compound gas to decompose and deposit material from the bottom of the trenches upward, preventing overhang formation and cavity formation near the openings.
Solution Approach 2:
The patent changes the irradiation direction from the vertical dimension (from opening to bottom) to the horizontal dimension (from side surface). This dimensional change allows electron beam penetration through the sample thickness, enabling uniform decomposition and deposition throughout the trench depth without overhang formation.
3Manufacturing precision
If electron beam irradiation is used to decompose compound gas, then deposition uniformity is improved, but the process complexity increases due to coordinated gas injection and beam control
Solution Approach 1:
The patent merges the electron beam irradiation process with the compound gas decomposition process into a single integrated operation. The electron beam serves dual purposes: it decomposes the compound gas to produce buried material and simultaneously provides the energy for deposition, simplifying the overall process control.
Solution Approach 2:
The electron beam automatically decomposes the compound gas at the location where deposition is needed, eliminating the need for separate heating or catalytic decomposition steps. The beam's energy directly converts the gas to solid material in situ, reducing process complexity.
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 allows for uniform trench filling without cavities, even in high aspect ratio trenches, by controlling the electron beam and gas deposition, ensuring efficient and compatible material usage.
Implementation Method 1
by irradiating an electron beam toward the inside of the trenches from a side surface extending along the depth direction of the sample piece
Implementation Method 2
decomposing the compound gas with secondary electrons generated by irradiation of the electron beam
Implementation Method 3
the compound gas injected into the inside of the trenches is decomposed by the secondary electrons whereby the solid constituents can be deposited within the trenches
Implementation Method 4
depositing constituents of the compound gas within the trenches
Data Source
AI summary
The invention provides a method of burying trenches of a sample comprises at least the steps of: from the sample having the trenches extending from one surface into a depth direction, cutting a sample piece of a small part including the trenches; and by irradiating an electron beam toward the inside of the trenches from a side surface extending along the depth direction of the sample piece and simultaneously injecting a compound gas into the inside of the trenches from openings on the side of the one surface of the trench, decomposing the compound gas with secondary electrons generated by irradiation of the electron beam and depositing constituents of the compound gas within the trenches. Therefore, the method can bury the trenches uniformly without generating cavities within the trenches even if the trenches of the sample piece have a high aspect ratio deep in a depth direction.