Wafer Support Pin Layout for Flash Annealing Bow Control
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Solution Overview
Problem
Flash lamp annealing can cause semiconductor wafers to bow, leading to displacement and potential breakage due to rapid thermal expansion, as existing support systems are inadequate in managing substrate deformation during high-energy flash light irradiation.
Innovation Solution
A substrate support device with a holding plate and substrate support pins arranged to maintain equal spacing between the plate and the substrate in both unbowed and bowed states, ensuring consistent support and preventing wafer jump and breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flash lamp annealing is used to rapidly heat the semiconductor wafer surface, then impurity activation is achieved without excessive diffusion, but the wafer bows due to rapid thermal expansion causing displacement and potential breakage
Solution Approach 1:
The support system is segmented into multiple individual support pins distributed across the wafer surface, allowing each pin to independently accommodate local deformation while maintaining overall support. This segmentation enables the system to handle the bowing caused by flash lamp annealing without causing wafer breakage.
Solution Approach 2:
The support pins are designed with dynamic characteristics that allow them to adapt to the changing wafer shape during rapid heating. The pins can move or deform slightly to accommodate the bowing, transforming the rigid support system into a more flexible one that maintains contact with the wafer surface throughout the annealing process.
2Temperature
If conventional heating methods are used, then the wafer is heated uniformly, but impurities diffuse to greater depths than desired
Solution Approach 1:
The heating is applied locally to only the surface region of the wafer where impurities have been implanted, rather than heating the entire wafer uniformly. This localized heating approach allows the surface to reach high temperatures for impurity activation while the bulk remains cooler, preventing excessive diffusion and maintaining precise junction depth control.
Solution Approach 2:
The flash lamp annealing uses periodic, pulsed illumination rather than continuous heating. The extremely short duration pulses deliver intense heat rapidly to activate impurities, then immediately stop to prevent the heat from penetrating deeper and causing unwanted diffusion, achieving both surface activation and depth precision.
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
The solution effectively suppresses semiconductor wafer breakage by maintaining stable support during flash light-induced bowing, ensuring reliable thermal processing without substrate displacement.
Implementation Method 1
Radiation spectral distribution of the xenon flash lamp is in an ultraviolet range to a near infrared range, has a shorter wavelength than that of a conventional halogen lamp, and is substantially coincident with a fundamental absorption band of a semiconductor wafer made of silicon. Thus, in a case where the semiconductor wafer is irradiated with flash light from the xenon flash lamp, the temperature of the semiconductor wafer can rapidly be increased because less light is transmitted.
Implementation Method 2
If raid thermal expansion occurs on the surface of the substrate irradiated with flash light, the substrate can be bowed so that the surface thereof is convex.
Data Source
AI summary
A substrate support device relating to technology disclosed in the description of the present application includes: a holding plate for opposing a substrate bowable by being heated by irradiation with flash light; and a plurality of substrate support pins provided on the holding plate and being for supporting the substrate, wherein the plurality of substrate support pins are arranged at locations where a volume of a space between the holding plate and the substrate in an unbowed state and a volume of a space between the holding plate and the substrate in a bowed state are equal to each other. Breakage of the substrate can be suppressed in a case where the substrate is bowed by flash light.