Passivated Chip Sides to Block Solder Rise in CSP Assembly
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Solution Overview
Problem
During the assembly of CSP-type chips, solder can rise along the sides of the chip, leading to electrical performance issues such as short circuits and leakage current due to the semiconductor material composition of the chip sides.
Innovation Solution
A method for manufacturing electronic chips with passivated sides involves forming trenches or cavities between chips, depositing insulating material within these features, and then separating the chips by cutting through the insulating material, thereby preventing solder from coming into contact with the semiconductor sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chips are assembled with solder, then electrical connection is achieved, but solder can rise along the sides of the chip causing short circuits and leakage current
Solution Approach 1:
An insulating material layer is introduced as an intermediary between the solder and the semiconductor substrate sides. This layer prevents direct contact between the solder and the conductive semiconductor material, thereby blocking the harmful effect of solder rising along the chip sides while maintaining the beneficial electrical connection function.
Solution Approach 2:
The insulating material is applied locally to the sides of the semiconductor substrate where solder contamination is most likely to occur. This localized treatment provides protection exactly where needed without affecting other areas of the chip, such as the connection pads on the first face that require electrical connectivity.
2Reliability
If insulating material is deposited in trenches or cavities, then solder rising is prevented, but manufacturing process complexity increases
Solution Approach 1:
Trenches or cavities are formed in the semiconductor substrate before the final chip assembly process. By preparing these structural features in advance, the subsequent deposition of insulating material becomes a straightforward filling operation rather than a complex application process, thereby reducing overall manufacturing complexity while achieving reliable solder protection.
Solution Approach 2:
The insulating material is deposited using inkjet printing technology, which replaces traditional mechanical deposition methods. This substitution enables precise, controlled application of the insulating material directly into the trenches or cavities, simplifying the manufacturing process while ensuring accurate placement and minimal material waste.
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 method effectively prevents solder from rising along the sides of the chips, thereby avoiding electrical performance degradation and ensuring reliable chip assembly and operation.
Implementation Method 1
the insulating material is deposited by inkjet printing
Data Source
Figure 1A~1D
Figure 2A~2D
Figure 3A~3E
AI summary
The present description relates to a method for manufacturing an electronic chip with passivated sides from a semiconductor substrate (110) of which a first face is covered by connection pads (107) and in which chips are formed, the method comprising the following steps: - forming trenches or cavities between the chips, - depositing an insulating material (121) in the trenches or cavities, - separating the chips by cutting at least the insulating material (121).