SOI Die Transfer Structure Using Oxide Tethers and Spacers
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Solution Overview
Problem
Existing mass transfer methods for dies in electronic devices face inefficiencies due to challenges in controlling the etching process, leading to issues with the number, size, and arrangement of transferred dies, which limits the overall efficiency.
Innovation Solution
A method and structure utilizing an oxide layer supporting feature with a tether structure and spacers in a semiconductor-on-insulator substrate, allowing for die transfer without etching the material layer beneath the dies, thereby enhancing the number of dies per unit area and improving their arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an etching process is used to suspend the die for transfer, then the die can be transferred to the substrate, but the etching process is difficult to control leading to insufficient or excessive etching which reduces transfer efficiency
Solution Approach 1:
The patent uses a sacrificial tether structure made of oxide layer that is intentionally designed to be removed during the transfer process. This disposable tether allows the die to be suspended and transferred without requiring precise control of the etching process, as the tether's removal is part of the intended transfer mechanism rather than a critical precision step
Solution Approach 2:
The oxide layer is segmented into distinct regions: a tether region that connects the die to the support substrate, and a die setting region that holds the die. This segmentation allows the tether to be selectively removed while leaving the die intact, enabling transfer without requiring precise etching control across the entire die structure
2Quantity of substance
If traditional mass transfer methods are used, then dies can be transferred to the substrate, but the number, size, and arrangement of transferred dies are limited
Solution Approach 1:
The oxide layer serving as the tether structure also functions as the die setting region and provides mechanical support. This multi-functionality allows the same structure to accommodate dies of various sizes and arrangements without requiring separate support structures for each configuration
Solution Approach 2:
The patent allows modification of the oxide layer thickness, tether dimensions, and die setting region parameters to optimize for different die sizes and desired arrangements. By changing these parameters, the system can transfer varying numbers of dies per unit area while maintaining transfer efficiency
3Productivity
If the die is suspended by removing material layer through etching, then the die can be transferred, but insufficient or excessive etching occurs causing lower transfer efficiency
Solution Approach 1:
The tether structure is designed as a sacrificial element that is intentionally removed during transfer. Its removal is not a precision-critical step but rather a controlled release mechanism, making the process more reliable and less prone to variations in etching conditions
Solution Approach 2:
The oxide layer tether acts as an intermediary between the die and the support substrate. It provides a controlled interface that facilitates reliable transfer by mediating the separation process, ensuring that dies are released consistently without direct contact between the die and substrate during transfer
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 method increases the number of dies transferred per unit area and improves their mechanical strength and reliability by using an oxide layer for support and protection, enhancing the efficiency and reliability of the die bonded structure.
Implementation Method 1
an oxide layer supporting feature... The oxide layer supporting feature includes a plurality of repeating units, where each of the repeating units includes a die setting region and a peripheral region
Implementation Method 2
The spacer is disposed between the bonding feature and the supporting wafer, where the spacer is bonded to the bonding feature
Implementation Method 3
An etching process is performed on the oxide layer to separate the die setting region of one repeating unit from the peripheral region of another adjacent repeating unit of the oxide layer
Implementation Method 4
A bonding process is performed to bond the supporting wafer to the bonding feature through the spacer
Data Source
AI summary
A method of transferring dies includes providing a SOI substrate that includes an oxide layer formed between a semiconductor substrate and a semiconductor layer. Each die is formed on a die setting region of a repeating unit of the oxide layer. A bonding feature is formed on a peripheral region of the repeating unit and separated from the die. A spacer is formed on a supporting wafer. The supporting wafer is bonded to the bonding feature through the spacer by a bonding process. The supporting wafer is separated from the die and the bonding feature by a gap. The oxide layer is etching to separate the die setting region of one repeating unit from the peripheral region of another adjacent repeating unit. The semiconductor substrate is removed to expose the oxide layer after the bonding process.