Semiconductor Surface Profile Measurement Using Dynamic Laser Scanning
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Solution Overview
Problem
Existing methods for measuring the surface profile of semiconductor layers during vapor deposition are inadequate, particularly when the semiconductor layer is in a stationary state, as they fail to accurately detect warpage and curvature due to limited information from single laser beams and increased complexity with multiple light-emitting devices.
Innovation Solution
A method and apparatus that control the irradiation timing and reflection angle of a single laser beam using a pivot mirror system to vary the incident direction across multiple points on the semiconductor layer, allowing for precise surface profile analysis without moving the substrate, using a beam position sensor to detect reflected beams from multiple incident points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single laser beam with fixed irradiation direction is used to measure the surface profile, then the device complexity is reduced, but the measurement precision is insufficient because only one point can be irradiated at a time
Solution Approach 1:
The patent applies the dynamics principle by making the laser beam's irradiation direction variable through a rotating mirror. Instead of using multiple fixed laser beams, a single laser beam dynamically changes its incident direction to irradiate multiple points on the semiconductor layer surface sequentially. This resolves the contradiction by maintaining device simplicity while achieving multi-point measurement capability, thereby improving measurement precision without proportionally increasing device complexity.
2Area of stationary object
If the semiconductor layer is rotated to irradiate multiple points with a single laser beam, then the measurement coverage is improved, but the measurement time increases and productivity decreases
Solution Approach 1:
Instead of rotating the semiconductor layer, the patent dynamically rotates the mirror to change the laser beam's incident direction. This allows multiple points to be irradiated sequentially while keeping the semiconductor layer stationary, significantly reducing measurement time and improving productivity while maintaining comprehensive measurement coverage.
Solution Approach 2:
The patent segments the measurement process by dividing the surface into multiple irradiation points that are measured sequentially through different incident angles. The mirror rotation enables systematic segmentation of the measurement task across multiple angular positions, allowing comprehensive coverage without requiring physical movement of the semiconductor layer.
3Measurement precision
If a plurality of laser beams is used to irradiate multiple incident points, then the measurement precision is improved, but the device complexity increases due to multiple light-emitting devices
Solution Approach 1:
The patent applies the universality principle by making a single laser beam perform multiple functions: it sequentially irradiates multiple incident points on the semiconductor layer surface by changing its incident direction through mirror rotation. This single laser beam replaces what would otherwise require multiple laser beams or light-emitting devices, thereby improving measurement precision while avoiding the device complexity increase that would result from using multiple light sources.
Solution Approach 2:
The dynamic rotation of the mirror enables a single laser beam to function as multiple beams by directing it to different incident points at different times. This dynamic redirection achieves the multi-point measurement capability of multiple laser beams while maintaining the simplicity of a single light-emitting device.
4Ease of operation
If the irradiation direction of the laser beam is fixed, then the ease of operation is improved, but the measurement precision is insufficient for detecting curvature and warpage
Solution Approach 1:
The patent introduces dynamic control of the laser beam's incident direction through mirror rotation, enabling precise measurement of surface profile, curvature, and warpage. The automated mirror rotation system maintains ease of operation by eliminating the need for manual repositioning, while the variable incident angles provide the measurement precision necessary for detecting subtle surface irregularities.
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 accurate detection of surface profiles, including warpage and curvature, even when the substrate is stationary, with a reduced number of components and increased information, allowing for high-quality film formation by correcting warpage in real-time.
Implementation Method 1
a beam position sensor to detect the reflection direction of the laser beam
Implementation Method 2
a certain point of the surface of a semiconductor layer is irradiated with a single laser beam
Implementation Method 3
the reflected beam from that point is detected using a beam position sensor
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
[Technical Problem] An object is to provide a method and apparatus for measuring a surface profile that enable correction or the like of the surface profile through measuring the surface profile of a semiconductor layer when forming the semiconductor layer by a vapor deposition method. [Solution] A single laser beam is reflected by a movable mirror to generate incident laser beams (Ld1, Ld2 and Ld3) separated substantially into three beams, and incident points (P1, P2 and P3) on the surface of a semiconductor layer (7) being formed in a chamber (2) are irradiated with the incident laser beams (Ld1, Ld2 and Ld3). A beam position sensor detects reflected laser beams (Lv1, Lv2 and Lv3) from the irradiation points (P1, P2 and P3) thereby to measure the surface profile of a film that includes the incident points (P1, P2 and P3).