Silicon Handler Laser-Release Layers for Low-Damage Wafer Debonding
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Solution Overview
Problem
The challenge in semiconductor device fabrication is efficiently handling thin wafers without damage during three-dimensional chip integration, where conventional laser-release methods require high-power lasers and can cause unintended absorption and damage due to low absorption rates in debonding layers.
Innovation Solution
A wafer handling method using a bonding layer comprising a debonding layer, an optical enhancement layer, and an anti-reflection layer, where the debonding layer absorbs specific laser energy, and the optical enhancement layer confines it to ensure efficient release of the wafer with lower-power lasers, minimizing heat generation and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-power lasers are used to heat the debonding layer, then the wafer can be released, but the cost of the debonding process increases and thermal damage may occur to the wafer or surrounding structures
Solution Approach 1:
The bonding layer is designed with spatially varying optical properties: the debonding layer has high laser absorption coefficient while the handler layer has low absorption. This local differentiation ensures that laser energy is concentrated where needed (at the debonding layer) while protecting other regions from thermal damage
Solution Approach 2:
The patent changes the optical absorption parameters of different layers by selecting materials with specific properties. The debonding layer uses materials with high absorption coefficients at the laser wavelength, while the handler layer uses materials with low absorption, thereby controlling the distribution of thermal energy during laser irradiation
2Ease of manufacture
If conventional laser-release methods are used with low absorption rates in debonding layers, then the setup is simple, but high-power lasers are required which increases process cost and risk of damage
Solution Approach 1:
The patent modifies the optical absorption parameters of the bonding layer materials. By selecting a debonding layer material with high absorption coefficient at the laser wavelength, the system achieves efficient energy coupling without requiring high laser power, thus maintaining process simplicity while reducing power requirements
Solution Approach 2:
The bonding layer is constructed as a composite structure with multiple functional layers (debonding layer and handler layer) having different optical properties. This composite design enables the system to achieve both high absorption where needed and low absorption where not needed, improving overall process efficiency
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 method enhances the efficiency and safety of wafer handling by concentrating laser energy absorption within the debonding layer, allowing for lower-power laser use and reducing the risk of thermal damage to the wafer and surrounding structures.
Implementation Method 1
a laser that emits laser energy at a wavelength that is absorbed by the debonding layer
Implementation Method 2
confined to the debonding layer by the optical enhancement layer
Implementation Method 3
An optical enhancement layer is formed from a material that is transparent at the wavelength and that has an index of refraction greater than 2.0, to confine energy at the wavelength of light to the debonding layer
Implementation Method 4
the material of the debonding layer ablates when exposed to the laser energy to release the wafer
Implementation Method 5
the material of the debonding layer ablates when exposed to the laser energy
Data Source
AI summary
Handler wafers and methods of handling a wafer include positioning a handler, which is attached to a wafer by a bonding layer that comprises a debonding layer, an optical enhancement layer, and an anti-reflection layer. The handler is debonded from the wafer using a laser that emits laser energy at a wavelength that is absorbed by the debonding layer and that is confined to the debonding layer by the optical enhancement layer, such that the material of the debonding layer ablates when exposed to the laser energy to release the wafer.