3D Interconnection Glue Filling with Passivation-Controlled Wetting
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Solution Overview
Problem
Existing encapsulation methods for interconnections between active elements and supports in 3D integration face issues such as mechanical stress, rupture, incomplete filling, and voids due to capillary spreading of glue, which also interfere with subsequent manufacturing steps like photolithography, especially on large surfaces.
Innovation Solution
A method involving the formation of a first passivation layer on the contour to reduce glue wetting and a second passivation layer to enhance glue wettability, using self-assembled monolayers with specific compounds like perfluorodecyltrichlorosilane and epoxybutyltrimethoxysilane, respectively, to manage interface energies and prevent meniscus coverage while ensuring complete filling without voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If glue is supplied to fill the space of interconnections via capillarity, then the space is filled with glue, but the glue creates a meniscus that covers the contour and generates mechanical stresses causing rupture
Solution Approach 1:
The contour is pre-treated with a plasma process before glue application to modify its surface properties. This preliminary action creates a surface that prevents meniscus formation and glue adhesion on the contour, allowing complete filling without mechanical stress concentration that would cause rupture
Solution Approach 2:
The surface energy parameters of the contour are changed through plasma treatment to make it non-adhesive to the glue. This parameter modification ensures that the glue does not wet the contour surface, preventing meniscus formation while still allowing complete capillary filling of the interconnection space
2Area of stationary object
If the active element surface is large (greater than 1 cm2), then more interconnections are needed, but the capillarity force becomes insufficient and filling is incomplete with voids appearing
Solution Approach 1:
The front face and main face are pre-treated with plasma to enhance their wettability before glue application. This preliminary surface modification ensures that capillary forces remain sufficient even for large surface areas, enabling complete filling without voids
Solution Approach 2:
The surface energy of the front face and main face is increased through plasma treatment to enhance capillary wettability. This parameter change ensures that the capillarity force remains sufficient to drive complete glue filling even when the active element surface area exceeds 1 cm2
3Manufacturing precision
If the contour is covered by the meniscus, then the glue fills the space, but the topology associated with the meniscus makes subsequent photolithography steps impossible
Solution Approach 1:
The contour is pre-treated with plasma to create a non-adhesive surface before glue application. This preliminary action prevents meniscus formation and ensures that the glue does not cover the contour, thereby preserving the ability to perform subsequent photolithography steps
Solution Approach 2:
The surface energy parameters of the contour are modified through plasma treatment to prevent glue adhesion. This parameter change ensures complete filling while maintaining contour accessibility for subsequent photolithography and other processing steps
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 approach effectively limits meniscus-induced mechanical stress, achieves complete and void-free filling, and allows for subsequent manufacturing steps like photolithography, even on large surfaces, by controlling glue wetting and interface energies through passivation layers.
Implementation Method 1
made from a first compound making it possible to limit the wetting of said contour by the glue
Implementation Method 2
when it spreads via capillarity, the glue creates a meniscus M
Implementation Method 3
formed on the front face and on the main face, made from a second compound making it possible to increase the wettability of said front face and of said main face by the glue
Data Source
AI summary
A method for manufacturing a structure includes: supplying an active element provided with a front and rear face connected by a contour; assembling the front face and a main face of a support; filling a space of interconnections between the front face and the main face with glue. The method also includes, before the assembling, forming, by a method other than a plasma method, a first passivation layer covering the contour, and made from a first compound that makes it possible to limit the wetting of said contour by the glue regarding the front face and the main face.