Au-Sn Package Lid Peeling Prevention via Phase-Controlled Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for manufacturing package lid members using Au—Sn layers on glass substrates face issues with peeling off due to differences in shrinkage ratios during cooling, leading to potential damage and detachment from the substrate.
Innovation Solution
A method involving a metalizing step, applying Au—Sn paste on metalized layers, reflowing, and a controlled cooling step where the Au—Sn paste is held between 150°C and 190°C for 2 minutes or longer to transform the ξ phase into a softer ξ′ phase, reducing the coefficient of linear expansion mismatch and preventing peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Au—Sn paste is applied and reflowed on glass plate material, then bonding between package lid member and substrate is achieved, but due to difference in shrinkage ratio at cooling, the Au—Sn layer may peel off or glass plate material may peel off, causing damage
Solution Approach 1:
The invention changes the cooling parameters by introducing a holding step at temperatures of 100°C or higher but lower than the solidification temperature for a predetermined period. This parameter modification allows the Au—Sn layer to cool and solidify without excessive shrinkage stress, preventing peeling while maintaining bonding strength.
Solution Approach 2:
The invention performs preliminary action by controlling the cooling process before complete solidification. The holding step at elevated temperature during cooling prepares the Au—Sn layer for stress-free solidification, preventing future peeling issues while ensuring reliable bonding.
2Productivity
If rapid cooling is performed after reflowing Au—Sn paste, then productivity is improved, but the Au—Sn layer peels off from the glass plate material
Solution Approach 1:
The invention modifies the cooling rate parameter by introducing a controlled holding period at 100°C or higher during the cooling process. This parameter change prevents peeling while maintaining reasonable productivity by not requiring extremely slow cooling throughout the entire process.
Solution Approach 2:
The cooling process is divided into periodic stages: initial rapid cooling followed by a holding period at elevated temperature, then continued cooling. This periodic approach balances productivity and layer integrity by applying different cooling rates at different stages.
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 effectively suppresses peeling and damage to the Au—Sn layer, ensuring a stable bond between the package lid member and the substrate, thereby preventing the Au—Sn layer from detaching from the glass substrate.
Implementation Method 1
a reflow step of heating and reflowing the Au—Sn paste applied to the glass member after the paste applying step
Implementation Method 2
a cooling step of cooling the reflowed Au—Sn paste. The cooling step includes a holding step of holding the reflowed Au—Sn paste in a temperature range of 150° C. or higher and 190° C. or lower for a holding time of 2 minutes or longer
Implementation Method 3
an Au—Sn layer formed of an Au—Sn alloy obtained by melting and solidifying the Au—Sn paste is formed at the bonding portion of the glass member
Implementation Method 4
a metalizing step of forming a metalized layer at a bonding portion provided on a surface of a glass member
Data Source
AI summary
A method for manufacturing a package lid member includes a metalizing step of forming a metalized layer on a surface of a glass member, a paste applying step of applying an Au—Sn paste on the metalized layer in a frame shape, a reflow step of heating the glass member to which the Au—Sn paste was applied after the paste applying step and reflowing the Au—Sn paste, and a cooling step of cooling the glass member after the reflow step to form an Au—Sn layer. The cooling step includes a holding step of holding the glass member in a temperature range of 150° C. or higher and 190° C. or lower for 2 minutes or longer.