Non-Conductive Film Thermo-Compression Bonding for Semiconductor Packages
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving enhanced reliability and efficiency, particularly in 3D integrated devices where thermal expansion coefficient mismatch can lead to BEOL crack and bump-open failures, and existing methods like reflow processes are limited in controlling mechanical properties and stress on bumps.
Innovation Solution
The use of a non-conductive film (NCF) in a thermo-compression process to bond semiconductor chips to package substrates, where the NCF surrounds connection terminals and is supported by a side encapsulation material, enhancing mechanical strength and reliability by alleviating stress on bumps and preventing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reflow process is used to bond semiconductor chip to package substrate, then bonding is achieved, but thermal expansion coefficient mismatch causes BEOL crack and bump-open failures
Solution Approach 1:
A non-conductive film (NCF) is introduced as an intermediary layer between the semiconductor chip and package substrate. This NCF serves as a stress buffer that absorbs thermal expansion coefficient mismatch, preventing stress transmission to the bumps and BEOL structures while maintaining bonding functionality.
Solution Approach 2:
The bonding process parameters are changed from conventional reflow to thermo-compression bonding. This involves applying controlled temperature and pressure conditions that enable reliable bonding without subjecting the bumps to excessive thermal stress, thereby preventing bump-open failures and BEOL cracks.
2Strength
If NCF is used in thermo-compression process to bond chip to substrate, then mechanical strength is enhanced and stress on bumps is alleviated, but manufacturing process complexity increases
Solution Approach 1:
The NCF performs multiple functions simultaneously: it acts as an adhesive for bonding, a stress buffer for thermal mismatch, and a structural support element. By merging these functions into a single component, the overall device structure is simplified despite the enhanced manufacturing process.
Solution Approach 2:
The NCF is implemented as a thin film structure that provides flexible stress absorption and mechanical support. This thin film approach maintains compact device dimensions while delivering the required mechanical strength and stress relief functionality.
3Reliability
If side encapsulation material is added to support NCF, then delamination is prevented and reliability is improved, but device structure becomes more complex
Solution Approach 1:
The side encapsulation material is positioned to wrap around and support the NCF structure, creating a nested configuration where the encapsulation material provides external support to the NCF. This nested arrangement prevents delamination while maintaining a compact integrated structure.
Solution Approach 2:
The side encapsulation material extends the protection and support from the planar bonding interface into the vertical dimension, wrapping around the sides of the NCF and chip structure. This dimensional extension provides comprehensive delamination prevention without significantly increasing horizontal footprint.
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 improves the reliability of semiconductor packages by reducing thermal stress and preventing delamination, allowing for higher integration density and efficient heat dissipation through the use of a thermo-compression process and appropriate filler content in the NCF, resulting in enhanced mechanical strength and reduced manufacturing costs.
Implementation Method 1
a non-conductive film (NCF) between the package substrate and the semiconductor chip, the NCF surrounding the connection terminal and bonding the semiconductor chip to the package substrate
Implementation Method 2
a side encapsulation material covering a side surface of the semiconductor chip, contacting the package substrate, and including a first portion between a bottom surface of the semiconductor chip and the top surface of the package substrate
Implementation Method 3
At least a portion of the NCF includes a second portion that horizontally protrudes from the semiconductor chip when viewed from above
Data Source
AI summary
A semiconductor package including a package substrate, a semiconductor chip on a top surface of the package substrate, a connection terminal between the package substrate and the semiconductor chip, the connection terminal connecting the package substrate to the semiconductor chip, a non-conductive film (NCF) between the package substrate and semiconductor chip, the NCF surrounding the connection terminal and bonding the semiconductor chip to the package substrate, and a side encapsulation material covering a side surface of the semiconductor chip, contacting the package substrate, and including a first portion between a bottom surface of the semiconductor chip and the top surface of the package substrate may be provided. At least a portion of the NCF includes a second portion that horizontally protrudes from the semiconductor chip when viewed, and a portion of the side encapsulation material is in contact with the bottom surface of the semiconductor chip.