Nitride Semiconductor Substrate Surface Layout for Warp and Side Detection
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Solution Overview
Problem
Group-III element nitride semiconductor substrates face challenges in distinguishing between main and back surfaces, leading to errors in optical sensor detection and warping issues, which affect device production processes.
Innovation Solution
A substrate design where both surfaces are mirror surfaces, with only the outer peripheral region of the back surface being non-mirror finished, allowing for easy visual distinction and reducing warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If both surfaces are subjected to mirror finish, then the warping of the substrate is reduced, but it becomes difficult to visually distinguish the main surface and back surface from each other
Solution Approach 1:
The patent applies different surface finishes to different regions of the back surface: the central region receives mirror finish to maintain stability and reduce warping, while the peripheral region receives non-mirror finish to enable visual distinction. This local differentiation resolves the contradiction by assigning different properties to different parts of the same surface.
2Area of stationary object
If both surfaces are subjected to mirror finish, then the effective area of the substrate is maximized, but errors in detection of the end portion with optical sensors occur
Solution Approach 1:
The patent creates a localized non-mirror finished peripheral region on the back surface that serves as a detectable feature for optical sensors. This localized treatment allows the majority of the substrate area to remain mirror-finished (maximizing effective area) while providing a distinct peripheral marker for accurate end portion detection.
3Ease of operation
If the back surface is subjected to rough finish, then it is easy to visually distinguish the main surface and back surface, but warping is liable to occur in the entirety of the substrate
Solution Approach 1:
Instead of applying rough finish to the entire back surface, the patent limits the non-mirror finish to only the peripheral region. This localized approach provides sufficient visual distinction while maintaining mirror finish on the central region, thereby preventing the warping that would result from comprehensive rough finishing.
4Ease of operation
If a secondary orientation flat is formed in addition to primary orientation flat, then the main surface and back surface can be visually distinguished, but the effective area of the semiconductor substrate reduces
Solution Approach 1:
The patent uses surface finish differentiation (mirror vs. non-mirror) to create visual distinction between main and back surfaces, replacing the need for secondary orientation flats. This approach provides clear visual cues without requiring additional structural features that would reduce the effective area.
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 design enhances the detection of the substrate's end portion with optical sensors, maintains a large effective production area, and minimizes warping, thereby improving the reliability of semiconductor device production.
Implementation Method 1
when the semiconductor substrate is transparent, and the back surface is subjected to mirror finish, measurement light substantially passes through the semiconductor substrate, and hence the amount of a change between the quantity of the light to be output from a light source and the quantity of the light to be input to a detector may become so small as not to be detected with the optical sensor
Data Source
AI summary
Group-III element nitride semiconductor substrate including a first surface and a second surface that are easy to visually distinguish from each other. An end portion is easily detected with an optical sensor, a large effective area (area that can be used in device production) can be secured, and warping of the entirety of the substrate is reduced. A Group-III element nitride semiconductor substrate includes a first surface; and a second surface, wherein the first surface is a mirror surface, the second surface has a second-surface central region and a second-surface outer peripheral region, the second-surface central region is a mirror surface, and the second-surface outer peripheral region is a non-mirror surface.