Spatial Energy Control Mask for Semiconductor Annealing
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Solution Overview
Problem
The challenge in thermal annealing of semiconductor substrates is controlling the energy delivery to areas with different optical and thermal properties, as existing methods using two light sources increase the thermal budget and result in nonuniform surface temperatures, potentially damaging fragile areas.
Innovation Solution
A system and method utilizing a mask with zones of varying transmission coefficients to deliver specific amounts of energy to different areas of a substrate, ensuring each area reaches its target temperature while minimizing energy excess and maintaining uniformity within +/-1% across each area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two light sources are used to heat the patterned surface, then the surface temperature uniformity is improved, but the thermal budget increases
Solution Approach 1:
The mask is divided into multiple zones (first zone and second zone) with different transmission coefficients. Each zone is positioned to correspond to a specific area of the patterned surface, allowing different energy amounts to be delivered to different areas based on their optical and thermal properties
Solution Approach 2:
Different zones of the mask have different transmission coefficients tailored to the specific requirements of each area being heated. Areas with higher light absorption or slower heat diffusion receive different energy amounts compared to areas with lower absorption or faster diffusion, achieving uniform temperature without excessive thermal budget
2Device complexity
If uniform energy is delivered to all areas, then the device complexity is reduced, but the temperature control precision deteriorates due to pattern effects
Solution Approach 1:
A mask with spatially varying transmission coefficients is introduced as an intermediary between the light source and the patterned surface. This mask compensates for the pattern effects by delivering different energy amounts to different areas, achieving uniform temperature without requiring multiple light sources or complex control systems
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 precise control of energy delivery to areas with distinct optical and thermal properties, reducing damage from excessive energy and optimizing the manufacturing process by maintaining low thermal budgets and achieving uniform temperature distribution.
Implementation Method 1
the coating of a pattern determines the amount of light absorbed
Implementation Method 2
a mask with zones of varying transmission coefficients to deliver specific amounts of energy to different areas
Implementation Method 3
the surface of the areas exposed to the pulsed light beam is heated above 1000°C during several seconds
Implementation Method 4
A first pulsed light source emits a first pulsed light beam towards a first area of a processed surface of a processed substrate
Implementation Method 5
the material and structure of the pattern determines its heat diffusion i.e. the rate at which heat is redistributed across the pattern and to the neighboring areas
Implementation Method 6
Using a mask having a plurality of zones having their own transmission coefficient allows controlling the amount of energy delivered to each areas of the die
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
System (21) for spatially controlling an amount of energy delivered to a processed surface (5) of a processed substrate (1) comprising a first area (11) and a second area (13), said first area having a first combination of optical properties and thermal properties, and said second area having a second combination of optical properties and thermal properties, said first combination and second combination being different, said system comprising a light source (23) configured to emit a pulsed light beam (27) towards the processed surface (5), wherein the pulsed light beam delivers a first amount of energy (E1) onto said first area of the processed surface so that said first area reaches a first target temperature (Tt1), and a second amount of energy (E2) to said second area of the processed surface so that said second area reaches a second target temperature (Tt2). A corresponding method is also described.