Semiconductor Package Assembly With Delayed UV Adhesive Curing
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Solution Overview
Problem
Undesired deformation of curable adhesive sheets during semiconductor manufacturing processes, such as plasma chemical etching, affects the reliability of semiconductor packages, leading to yield reduction and defects.
Innovation Solution
A method involving forming a bonding layer on a carrier, mounting semiconductor chips on a redistribution substrate, bonding a UV-curable adhesive sheet, separating the carrier, forming UBM and external connection conductors, cutting the package, and irradiating the adhesive sheet with UV rays after cutting to enhance adhesive strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the adhesive sheet is cured early in the manufacturing process, then the adhesive strength is maintained during processing, but the adhesive sheet deforms under plasma chemical etching and high-temperature conditions
Solution Approach 1:
The adhesive sheet is bonded to the package structure before the cutting process, securing the structure in advance. The timing of UV irradiation is strategically delayed until after cutting, allowing the adhesive to perform its holding function during critical processes while avoiding premature curing that would cause deformation.
Solution Approach 2:
The patent controls the curing state of the adhesive sheet by managing UV irradiation timing. The adhesive transitions from uncured to cured state at a specific point in the manufacturing process (after cutting), changing its physical properties from flexible and conformable to rigid and strong, thereby resolving the contradiction between maintaining adhesive strength and preventing deformation.
2Reliability
If the adhesive sheet is kept uncured during manufacturing processes, then deformation is prevented, but adhesive strength is insufficient for reliable bonding
Solution Approach 1:
The adhesive sheet is bonded to the package structure before the cutting process, securing the structure in advance. The timing of UV irradiation is strategically delayed until after cutting, allowing the adhesive to perform its holding function during critical processes while avoiding premature curing that would cause deformation.
Solution Approach 2:
The adhesive sheet undergoes a state transition from uncured to cured at a specific point in the manufacturing process. This periodic action (delayed UV irradiation) allows the adhesive to provide stability in uncured state during processing, then develop full bonding strength after cutting when irradiation occurs.
3Strength
If UV irradiation is applied early to the adhesive sheet, then adhesive strength is maximized, but the adhesive sheet cannot withstand subsequent high-temperature reflow processes
Solution Approach 1:
The adhesive sheet is bonded to the package structure before the cutting process, securing the structure in advance. The timing of UV irradiation is strategically delayed until after cutting, allowing the adhesive to perform its holding function during critical processes while avoiding premature curing that would cause deformation.
Solution Approach 2:
The patent controls the curing state of the adhesive sheet by managing UV irradiation timing. The adhesive transitions from uncured to cured state at a specific point in the manufacturing process (after cutting), changing its physical properties from flexible and conformable to rigid and strong, thereby resolving the contradiction between maintaining adhesive strength and preventing deformation.
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 ensures high yield and prevents defects by maintaining adhesive strength during manufacturing processes, particularly under high-temperature conditions, allowing for smooth separation and assembly of semiconductor packages.
Implementation Method 1
irradiating the UV-curable adhesive sheet with UV rays, after cutting the plurality of semiconductor packages
Implementation Method 2
an adhesive composition of the UV-curable adhesive sheet includes a photoinitiator having thermal stability so that 90% or more of an initial weight of the photoinitiator is maintained for 10 minutes at 200° C. or higher
Implementation Method 3
separating the carrier from the package structure using the release layer
Data Source
AI summary
Provided is a method of manufacturing a semiconductor package, the method including: forming a bonding layer on a carrier, forming a redistribution substrate on the bonding layer, mounting a plurality of semiconductor chips on the redistribution substrate, forming a package structure for a plurality of semiconductor packages; bonding an ultraviolet (UV)-curable adhesive sheet to a surface of the package structure opposite the bonding layer and redistribution substrate; separating or removing the carrier and the bonding layer from the package structure; forming an under bump metallurgy (UBM) layer and forming an external connection conductor on the redistribution substrate; cutting the package structure into the plurality of semiconductor packages; irradiating the UV-curable adhesive sheet with UV rays, after cutting the plurality of semiconductor packages; and separating the plurality of semiconductor packages from the UV-curable adhesive sheet.