Sputter Deposition Temperature Control for Whisker-Free Films
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Solution Overview
Problem
The formation of whiskers and thermal stress differences in deposition layers due to high-temperature substrate heating during PVD processes lead to yield reduction and non-uniformity, particularly near the substrate.
Innovation Solution
A deposition apparatus with a controller that measures temperature and thermal stress, compares these values to preset thresholds, and adjusts the voltage application to manage thermal stress differences, thereby controlling the deposition process to minimize whisker growth and ensure uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If substrate is heated to high temperatures during deposition, then deposition layer uniformity is improved, but thermal stress difference increases leading to whisker growth
Solution Approach 1:
The patent applies preliminary action by heating the substrate to high temperature before starting the deposition process. This ensures the substrate is already at the optimal temperature for uniform deposition before any material is deposited, preventing thermal stress differences that would occur if heating happened during deposition. The temperature is stabilized at the setpoint before deposition begins, so the entire deposition layer forms under uniform thermal conditions.
Solution Approach 2:
The patent implements dynamics through real-time temperature monitoring and dynamic adjustment of heating power. The controller continuously measures substrate temperature and adjusts the heating power to maintain a stable setpoint temperature throughout the deposition process. This dynamic control prevents temperature fluctuations that would cause thermal stress variations and whisker growth, while ensuring uniform deposition conditions are maintained throughout the process.
2Object-affected harmful factors
If deposition is performed at room temperature, then thermal stress is reduced, but deposition layer uniformity deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-heating the substrate to the optimal deposition temperature before starting material deposition. This ensures that the substrate is already at the correct temperature for achieving uniform deposition, eliminating the need to perform deposition at room temperature. The temperature is stabilized before deposition begins, so uniformity is achieved without compromising thermal stress management.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the substrate temperature to an optimal setpoint that balances deposition uniformity and thermal stress. The controller modifies the heating parameter (temperature) to a specific value that enables high-quality uniform deposition while preventing excessive thermal stress. This optimal temperature parameter is maintained throughout the deposition process to achieve both goals simultaneously.
3Reliability
If temperature control is added to manage thermal stress, then process complexity increases, but yield improves
Solution Approach 1:
The patent implements feedback control by continuously measuring the substrate temperature with a temperature sensor and using this measurement to adjust the heating power through a controller. The controller compares the measured temperature with the desired setpoint and dynamically adjusts the heating element to maintain the optimal temperature. This closed-loop feedback system automatically manages thermal stress and prevents whisker growth, improving yield while keeping the control system relatively simple through automated regulation.
Solution Approach 2:
The patent applies self-service through an automated temperature control system that monitors and adjusts substrate temperature without manual intervention. The controller automatically maintains the substrate at the optimal deposition temperature by adjusting heating power based on real-time temperature measurements. This self-regulating system eliminates the need for complex manual control procedures while ensuring consistent temperature management throughout the deposition process, improving reliability without proportionally increasing complexity.
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 apparatus effectively minimizes whisker generation and improves yield by maintaining uniform thermal stress across the deposition layer, enhancing film quality and economic efficiency.
Implementation Method 1
PVD may be classified into thermal evaporation, electron-beam (E-beam) evaporation, and sputtering
Implementation Method 2
the formed deposition layer has higher thermal stress as being closer to the substrate
Implementation Method 3
PVD is known as a manner of depositing a target material for deposition on a substrate and forming a deposition layer
Data Source
AI summary
A deposition apparatus includes a chamber configured to accommodate a target substrate that is configured to discharge a target material, a deposition substrate on which a deposition layer including the target material is formed, and an electrode substrate in contact with the deposition substrate, a voltage applying device configured to apply a voltage to the target substrate and the electrode substrate, a temperature measurement part configured to measure a temperature of the deposition substrate, a controller configured to calculate at least one of a temperature change rate and an absolute value of the temperature change rate based on a process time through the temperature of the deposition substrate measured in the temperature measurement part, compare the absolute value of the calculated temperature change rate and a preset threshold temperature change rate, control operation of the voltage applying device, and perform a deposition process for forming the deposition layer.