Semiconductor Substrate Thinning via Laser Damage and Ultrasonic Separation
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Solution Overview
Problem
Current semiconductor substrate manufacturing processes, particularly for silicon carbide, face challenges in efficiently thinning substrates due to material limitations and equipment constraints, leading to difficulties in achieving substrates below a certain thickness and effective separation from boules.
Innovation Solution
The method involves inducing damage layers at specific depths within the substrate using laser irradiation and applying ultrasonic energy to separate the substrate into thinned portions, which can be further processed for reuse, allowing for the formation of multiple thinned substrates from a single boule and reducing material loss during backgrinding and sawing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sawing and polishing processes are used to thin semiconductor substrates, then substrates can be separated from boules, but material loss is significant and substrates below certain thickness cannot be achieved
Solution Approach 1:
The substrate is divided into multiple sections by creating damage layers at different depths, allowing selective separation and thinning of specific portions while preserving others for reuse as carrier substrates
Solution Approach 2:
Damage layers are induced in advance at predetermined depths using laser irradiation before separation, enabling precise thickness control and reducing the need for extensive material removal during subsequent processing
2Productivity
If multiple substrates are separated from a single boule, then productivity increases, but the complexity of the separation process increases
Solution Approach 1:
Multiple damage layers are created at different depths to enable sequential separation of multiple substrates from a single boule, with each layer serving as a separation plane for one substrate
Solution Approach 2:
Conventional mechanical sawing is replaced with laser-induced damage layer formation followed by ultrasonic separation, reducing mechanical complexity while enabling multiple substrate separations
3Temperature
If substrates are thinned to improve heat management, then device performance improves, but the difficulty of processing and separation increases
Solution Approach 1:
Damage layers are formed at predetermined depths before thinning operations, providing natural separation planes that simplify subsequent thinning processes and enable precise thickness control
Solution Approach 2:
The physical state of the substrate is changed by inducing damage layers that alter the material structure, making thinning and separation operations easier while achieving the desired thin thickness for heat management
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 enables the production of thinner, high-performance semiconductor substrates with improved heat management and reduced processing costs by effectively separating and reprocessing silicon carbide substrates, enhancing the manufacturing efficiency and profitability.
Implementation Method 1
inducing damage layers at specific depths within the substrate using laser irradiation
Implementation Method 2
applying ultrasonic energy to separate the substrate into thinned portions
Data Source
AI summary
Implementations of methods of thinning a semiconductor substrate may include: providing a semiconductor substrate having a first surface and a second surface opposing the first surface, the semiconductor substrate having a thickness between the first surface and the second surface. The method may further include inducing damage into a portion of the semiconductor substrate at a first depth into the thickness forming a first damage layer, inducing damage into a portion of the semiconductor substrate at a second depth into the thickness forming a second damage layer, and applying ultrasonic energy to the semiconductor substrate. The method may include separating the semiconductor substrate into three separate thinned portions across the thickness along the first damage layer and along the second damage layer.