Temporary Chip Attach Carrier for Fine Pitch IC Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing fineness of integrated circuit chip interconnects, such as solder balls, makes it difficult to remove chips from temporary carriers without damaging them during testing at non-room temperatures.
Innovation Solution
A temporary chip attach carrier with a substrate and interposer, both made from materials matching the chip's substrate, featuring arrays of interconnects and pads connected by wires, allowing for secure attachment and easy removal of integrated circuit chips during testing, using techniques like reflow and shear forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If integrated circuit chips with fine pitch interconnects are temporarily attached to a carrier for testing, then testing capability is enabled, but removal of the chip becomes difficult and may cause damage
Solution Approach 1:
The carrier is segmented into a substrate and an interposer layer. The interposer acts as an intermediate structure that can be selectively removed or detached, allowing the chip to be released without damaging the fine pitch interconnects. This segmentation enables the testing function while providing a controlled release mechanism.
Solution Approach 2:
The interposer serves as an intermediary between the chip and the substrate. It provides a temporary bonding interface during testing that can be cleanly separated, protecting the chip's fine pitch interconnects during both attachment and removal processes. The intermediary structure absorbs the mechanical stress of bonding and debonding operations.
2Strength
If the carrier is designed for secure attachment of chips, then attachment reliability improves, but chip removal becomes more difficult
Solution Approach 1:
The bonding interface is designed to be dynamic rather than permanent. The interposer provides strong attachment during testing through controlled bonding processes, but enables clean removal through controlled debonding mechanisms. This dynamic characteristic allows the system to transition between strongly bonded and easily separatable states as needed.
Solution Approach 2:
The bonding parameters are optimized to provide sufficient strength for testing while maintaining removability. By controlling bonding temperature, pressure, and time parameters, the attachment achieves adequate strength for reliable testing but remains reversible. The interposer material properties are selected to allow controlled debonding after testing completes.
Data Source
AI summary
A temporary chip attach carrier for and a method of testing an integrated circuit chip. The carrier includes: a substrate, a first array of interconnects disposed on a bottom surface and a second array of interconnects disposed on a top surface of the substrate, corresponding interconnects of the first and second arrays of interconnects electrically connected by wires in the substrate; an interposer, a first array of pads disposed on a top surface of the interposer and a second array of pads disposed on a bottom surface of the interposer, corresponding pads of the first and second arrays of pads electrically connected by wires in the interposer, and pads of the second array in direct physical and electrical contact with corresponding interconnects of the second set of interconnects; and wherein the interposer includes an interposer substrate of the same material as a substrate of the integrated circuit chip.