Wafer Chip Packaging With Inert Gas for Clean Long-Term Delivery
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Solution Overview
Problem
Wafers divided into individual device chips are prone to contamination from powdery dust particles when stored for long periods, leading to reduced quality, especially when processing facilities are far apart and storage is prolonged.
Innovation Solution
A method involving forming a package unit with a wafer surrounded by dicing tape and a thermal-pressure-bonding sheet, with an inactive gas fill, such as nitrogen, to protect the chip surfaces and prevent oxidation of metal parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If wafers are divided into individual device chips and stored for long periods, then delivery to distant factories is enabled, but contaminants such as powdery dust particles are deposited on the surfaces of the device chips, lowering quality
Solution Approach 1:
The patent applies this principle by filling the storage container with inert gas (nitrogen or carbon dioxide) to displace oxygen and create a contaminant-free environment. The inert gas prevents oxidation and eliminates the presence of powdery dust particles that would otherwise deposit on device chip surfaces during long-term storage and delivery.
Solution Approach 2:
The patent applies this principle by sealing device chips within a container that has a flexible or hermetic seal, creating a physical barrier between the device chips and the external environment. This enclosure prevents contaminants from reaching the chip surfaces while allowing for transport and storage.
2Loss of time
If wafers are divided into individual device chips and kept for extended periods, then delivery logistics are improved, but metal parts of the devices undergo oxidation, reducing quality
Solution Approach 1:
The patent applies this principle by introducing inert gas into the storage container to replace the ambient air environment. This inert atmosphere prevents oxidation reactions of metal parts by eliminating oxygen contact, thereby maintaining the reliability and quality of device chips during extended delivery periods to distant factories.
Solution Approach 2:
The patent applies this principle by using inert gas as an intermediary substance between the metal parts and oxygen. The inert gas acts as a mediator that physically separates oxygen from the metal surfaces, preventing oxidation reactions while allowing the device chips to be stored and transported over extended periods.
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 effectively prevents contamination and oxidation, maintaining the quality of device chips even when storage is prolonged, ensuring they remain in good condition until further processing.
Implementation Method 1
the thermal-pressure-bonding sheet is affixed to the other surface of the annular frame by heat and pressure in the package unit forming step
Implementation Method 2
the step of filling the space in the package unit with liquid nitrogen and expanding the liquid nitrogen in the package unit forming step
Implementation Method 3
filling a space in the package unit with an inactive gas... the individual device chips divided from the wafer also remain kept together by a dicing tape mounted on an annular frame while the device chips are disposed in a central opening of the annular frame
Data Source
AI summary
A method of handling a wafer includes a frame unit forming step of forming a frame unit by placing the wafer in a central opening of an annular frame, affixing a dicing tape to a surface of the annular frame, and affixing the wafer to the dicing tape, a dividing step of processing the wafer along projected dicing lines thereon to divide the wafer into individual device chips including respective devices, a package unit forming step of forming a package unit by affixing a sheet to another surface of the annular frame and surrounding the wafer with the dicing tape and the sheet, and a delivery step of delivering the package unit.