Laser Thin-Film Deposition with Local Stress Profile Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for controlling stress in thin films on substrates during laser deposition, such as bending substrates or post-treatment with laser heating, fail to achieve uniform or specific stress profiles effectively, limiting the quality and yield of MEMS and RF devices.
Innovation Solution
A method involving a laser deposition device with a movable target spot that adjusts parameters like temperature, pressure, and laser beam characteristics for each discrete surface portion on the substrate to control stress, allowing for a specific stress pattern and enabling uniform or non-uniform stress distribution as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate is bent during deposition to compensate stresses, then global stress compensation is achieved, but local stress control is not possible
Solution Approach 1:
The substrate surface is divided into multiple discrete surface portions, allowing independent stress control for each region. The laser beam is directed to different surface portions sequentially, enabling localized parameter adjustment and stress control without affecting the entire substrate uniformly.
Solution Approach 2:
Different deposition parameters (temperature, pressure, laser beam pulse duration, power, distance, spotsize, RF ionization energy) are applied to different surface portions of the substrate. This allows each region to have optimized local stress characteristics tailored to specific requirements, rather than applying a uniform global compensation approach.
2Stress or pressure
If laser beam is used for local heating to reduce stresses, then stress reduction is achieved, but crystal structure changes occur
Solution Approach 1:
Instead of using post-deposition laser heating, the invention adjusts deposition parameters (temperature, pressure, laser beam pulse duration, power, distance, spotsize, RF ionization energy) during the deposition process itself. This allows stress control through controlled parameter variations that avoid excessive thermal exposure and crystal structure changes.
3Manufacturing precision
If deposition parameters are adjusted for each surface portion, then uniform stress distribution is achieved, but process complexity increases
Solution Approach 1:
The laser beam position is dynamically moved across different surface portions of the substrate, and deposition parameters are adjusted in real-time based on the current surface portion being processed. This dynamic control enables uniform stress distribution while using a single laser source and basic parameter adjustment capabilities.
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 stress patterns in thin films, enhancing the quality and yield of MEMS and RF devices by ensuring even stress distribution and enabling tailored stress profiles for specific technical effects.
Implementation Method 1
a laser beam is directed onto a target spot on a surface of a target material. As a result, a plasma plume of target material is created, which is deposited onto the substrate
Implementation Method 2
a plasma plume of target material is created, which is deposited onto the substrate
Implementation Method 3
EP 2347993 describes a technique to reduce the stresses in layers also deposited by PVD or CVD. In this publication it is proposed to provide an after treatment of the substrate, by locally irradiating the layers on the substrate with a laser beam, such that the layers are locally heated
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The invention relates to a method for controlling stress in a substrate during laser deposition, which method comprises the steps of: - providing a laser deposition device comprising a chamber with a target holder with a target, a substrate holder with a substrate facing the target and a window, the laser deposition device further comprising a laser beam directed through the window of the chamber onto a spot at the target for generating a plasma plume of target material and depositing the target material onto a surface portion of the substrate in order to form a thin film of target material, wherein the target spot is movable relative to the substrate in order to deposit target material onto a plurality of surface portions of the substrate; - defining a plurality of discrete surface portions on the substrate; - aligning the target spot one after the other with each of the plurality of discrete surface portions and generating a plasma plume to deposit target material on each of the plurality of discrete surface portions; - adjusting at least one of the parameters of the deposition process depending on the discrete surface portion with which the target spot is aligned, which parameters comprise temperature, pressure, laser beam pulse duration, laser beam power, distance of target to substrate.