Semiconductor Finishing Process for Thin Layer Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing processes for forming thin semiconductor layers on substrates are complex and costly due to the need for multiple sacrificial oxidation and rapid thermal annealing operations, which can introduce defects and surface roughness, making it challenging to achieve the desired thickness and quality of the thin layer.
Innovation Solution
A simplified finishing process that involves creating a weakened zone in the donor substrate, applying a heat treatment to develop the weakening without initiating detachment, and using an energy pulse for self-maintained detachment, followed by a simplified sequence of rapid thermal annealing and sacrificial oxidation to achieve the desired thin layer thickness and surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple sacrificial oxidation and rapid thermal annealing operations are used to achieve desired thin layer thickness and quality, then the manufacturing precision and surface smoothness are improved, but the device complexity and production cost increase
Solution Approach 1:
The invention applies a heat treatment to develop the weakened zone before detachment, preparing the donor substrate in advance so that subsequent detachment and finishing operations can be simplified. This preliminary weakening allows for easier separation and reduces the complexity of subsequent thinning operations while maintaining precision.
Solution Approach 2:
The invention uses periodic rapid thermal annealing operations interspersed with sacrificial oxidation steps to progressively achieve the desired thin layer thickness and surface quality. This periodic combination of heating and oxidation cycles allows precise control over layer thickness and surface smoothness without requiring excessive continuous processing steps.
2Manufacturing precision
If multiple sacrificial oxidation operations are performed to thin the transferred layer, then the thin layer thickness is reduced to target specifications, but defects pass through and form HF type defects
Solution Approach 1:
The heat treatment develops the weakened zone to a critical state before detachment, ensuring that the zone is sufficiently weakened to allow clean separation. This preliminary preparation prevents the need for excessive subsequent thinning operations that would otherwise be required, thereby reducing the risk of defect formation during multiple oxidation cycles.
Solution Approach 2:
The invention modifies the thermal parameters by applying controlled heat treatment to develop the weakened zone without causing premature detachment. By carefully controlling temperature, time, and heating rate, the process achieves optimal weakening while preventing defect formation, allowing for reduced number of sacrificial oxidation steps.
3Manufacturing precision
If rapid thermal annealing is applied directly on the surface obtained after detachment, then the surface roughness is reduced, but a single RTA operation is inefficient in achieving desired smoothness
Solution Approach 1:
The heat treatment applied before detachment prepares the surface by developing the weakened zone and pre-smoothing the surface. This preliminary surface preparation reduces the roughness before the transferred layer is separated, thereby reducing the burden on subsequent RTA operations and improving overall process efficiency.
Solution Approach 2:
The invention maintains continuous surface smoothing action by combining the heat treatment during detachment with subsequent RTA operations. Rather than allowing the surface to roughen between detachment and finishing operations, the continuous thermal processing ensures progressive surface improvement, making the overall process more efficient than discrete separate operations.
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 reduces the number of operations, prevents the formation of through defects, and achieves a surface roughness of less than 5 Å RMS and a defect density of less than 0.3/cm², while maintaining the quality of the thin layer structure.
Implementation Method 1
applying heat treating the donor substrate to weaken the zone of weakness without initiating detachment
Implementation Method 2
a first rapid thermal anneal followed by a sacrificial oxidation step and then followed by a second rapid thermal anneal
Implementation Method 3
a first rapid thermal anneal followed by a sacrificial oxidation step and then followed by a second rapid thermal anneal
Data Source
AI summary
The invention relates to a process for the formation of a structure comprising a thin layer made of semiconductor material on a substrate, including the steps of providing a zone of weakness in a donor substrate; bonding the donor substrate to a support substrate; detaching a portion of the donor substrate to transfer it to the support substrate, wherein the detaching includes applying heat treating the donor substrate to weaken the zone of weakness without initiating detachment and applying an energy pulse to provoke self-maintained detachment of the donor substrate portion to transfer it to the support substrate; and subjecting the transferred portion of the donor substrate to a finishing operation to form a thin layer. The finishing operation is simplified compared to that which is conducted by a conventional process that achieves detaching by applying a heat treatment to provoke self-maintained detachment of the donor substrate portion, and the thin layer has a surface of the same smoothness as one prepared by the conventional process.