Wafer Bonding with Breakable Pillars for Compound Semiconductor Transfer
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Solution Overview
Problem
Current methods for creating compound semiconductor devices, particularly those using Germanium and silicon, are complex and inefficient, leading to high costs and process inefficiencies, which are not suitable for applications like long-range LIDAR that require infrared sensitivity.
Innovation Solution
A method of wafer bonding involving the generation of trenches and a cavity in a semiconductor wafer, allowing a semiconductor device to be connected to the wafer by a single connecting pillar, and then attaching it to a carrier wafer using a eutectic bond, enabling mechanical coupling and subsequent removal of the device by breaking the pillar, while allowing for reuse of the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If common methods of providing compound devices are used, then device functionality is achieved, but process complexity and costs increase significantly
Solution Approach 1:
The wafer is divided into multiple individual devices through trench generation, isolating each device in a separate cavity. This segmentation enables independent handling and bonding of each device, simplifying the overall manufacturing process by allowing parallel processing and reducing the complexity of handling entire wafers as single units.
Solution Approach 2:
A carrier wafer is introduced as an intermediary substrate to hold the semiconductor devices during the bonding process. This intermediary enables easy manipulation, transport, and alignment of devices without directly handling the fragile semiconductor structures, significantly reducing process complexity and improving ease of manufacture.
2Loss of substance
If semiconductor devices are bonded using traditional methods, then device coupling is achieved, but material consumption and chemical waste increase
Solution Approach 1:
The method enables recovery and reuse of the carrier wafer after device bonding. Once devices are transferred to their target substrate, the carrier wafer can be cleaned and reused for subsequent bonding operations, significantly reducing material consumption and chemical waste while maintaining reliable device coupling through the controlled bonding process.
Solution Approach 2:
The bonding process utilizes controlled changes in temperature and pressure parameters to achieve reliable device coupling. By optimizing these parameters, the process achieves strong, reliable bonds between devices and substrates while minimizing material consumption and chemical usage, resolving the contradiction between reliability and resource loss.
3Ease of operation
If devices are removed from wafer by breaking connecting pillars, then device separation is achieved, but mechanical stress may affect device integrity
Solution Approach 1:
The connecting pillars are designed with localized structural characteristics - narrower and more fragile at specific points - while the main device structures maintain their full strength. This local quality differentiation allows easy separation at the pillar level while preserving the structural integrity of the devices themselves, resolving the contradiction between ease of separation and device strength.
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 reduces material consumption, ohmic losses, and chemical waste, enabling energy and resource savings, and facilitates the creation of efficient compound semiconductor devices suitable for infrared applications.
Implementation Method 1
an eutectic bond arranged between the first main faces and mechanically coupling the first and second semiconductor dies to each other
Data Source
AI summary
A method for wafer bonding includes: providing a semiconductor wafer having a first main face; fabricating at least one semiconductor device in the semiconductor wafer, wherein the semiconductor device is arranged at the first main face; generating trenches and a cavity in the semiconductor wafer such that the at least one semiconductor device is connected to the rest of the semiconductor wafer by no more than at least one connecting pillar; arranging the semiconductor wafer on a carrier wafer such that the first main face faces the carrier wafer; attaching the at least one semiconductor device to the carrier wafer; and removing the at least one semiconductor device from the semiconductor wafer by breaking the at least one connecting pillar.