PDMS Mold Fixture for Low-Temperature IC Chip Attachment
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Solution Overview
Problem
Conventional methods for attaching IC chips and dies to physical objects, especially those with flexible low-temperature substrates, face challenges due to the inability to withstand high temperatures required for reflow soldering, and existing printing techniques are not practical for smooth interface creation between contact pads and surfaces.
Innovation Solution
The development of an electronic package fixture with sloped sidewalls and a mold made of PDMS, allowing for the use of structure forming materials like epoxy or UV curable polymers, which enables the creation of a flat surface for attaching IC chips or dies to physical objects using 3D printing and Anisotropic Conductive Film (ACF) bonding, facilitating low-temperature connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reflow soldering is used to attach IC chips and dies, then reliable electrical connections are achieved, but high temperature processing is required which cannot be withstood by flexible low-temperature substrates
Solution Approach 1:
The patent changes the bonding parameters from high-temperature reflow soldering to low-temperature eutectic bonding at approximately 45°C. This parameter change enables reliable electrical connections without exposing flexible substrates to damaging high temperatures, thus resolving the contradiction between connection reliability and temperature tolerance
Solution Approach 2:
The patent introduces an intermediary bonding process (eutectic bonding with eutectic paste) that mediates between the IC chip/die and the flexible substrate. This intermediary bonding method achieves reliable electrical and mechanical connections at low temperatures, avoiding both high-temperature soldering and direct contact between the chip and flexible substrate
2Ease of manufacture
If conventional printing techniques are used for trace formation, then conductive traces can be created, but smooth interface creation between contact pads and surfaces is not practical
Solution Approach 1:
The patent performs preliminary action by pre-forming raised contact pads on the flexible substrate before trace formation. This preliminary structuring creates a smooth interface that facilitates both precise trace alignment and reliable electrical connections, resolving the contradiction between ease of manufacture and manufacturing precision
Solution Approach 2:
The patent uses curved or sloped sidewalls on the raised contact pads instead of sharp edges. This curvature creates a smooth transition surface that improves trace adhesion and electrical contact, while still being manufacturable using standard printing and curing processes
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 solution allows for efficient and practical attachment of IC chips and dies to physical objects with flexible substrates, enabling reliable electrical connections while avoiding high-temperature processing limitations.
Implementation Method 1
UV curable polymers, which enables the creation of a flat surface for attaching IC chips or dies
Implementation Method 2
Anisotropic Conductive Film (ACF) bonding, facilitating low-temperature connections
Data Source
AI summary
Development of smart objects with electronic functions requires integration of printed components with IC chips or dies. Conventional chip or die bonding including wire bonding, flip chip bonding, and soldering may not be applicable to chip or die attachment on low temperature plastic surfaces used in physical objects. Printing conductive connection traces requires a smooth interface between contact pads of a chip and the surface of the physical object. In order to address this issue of chip/die attachment to a physical object, this disclosure provides embodiments to construct a fixture on a chip or die for attachment and electrical connection onto a physical object by printing operations and/or ACF bonding methods.