Semiconductor Gap Control Electrode for Flip Chip Short Circuit Prevention
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Solution Overview
Problem
The existing flip chip technique faces challenges in controlling the gap between a semiconductor chip and a packaging substrate, leading to potential short circuits due to the expulsion of solder between the columnar metal layer and wiring, especially when the gap becomes excessively narrow.
Innovation Solution
Incorporating a gap control electrode with a columnar metal layer and a solder layer, where the columnar metal layer and solder resist layer overlap, to maintain a stable gap and prevent short circuits by ensuring the solder is not expelled, allowing for a narrower inter-electrode pitch without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gap between the semiconductor chip and packaging substrate is reduced to increase connection density, then the inter-terminal pitch can be reduced, but solder may be expelled causing short circuits between adjacent wirings
Solution Approach 1:
The patent introduces a gap control electrode as an intermediary component between the semiconductor chip and packaging substrate. This electrode maintains a controlled gap that prevents solder expulsion while enabling narrow inter-terminal pitch, thus resolving the contradiction between connection density and short circuit prevention
Solution Approach 2:
The patent changes the physical parameters of the bonding structure by introducing a columnar metal layer with specific height and overlap dimensions. The overlap region between the columnar metal layer and solder resist layer creates a controlled gap that maintains reliability while allowing reduced pitch
2Length of stationary object
If a columnar metal layer with solder layer is used to ensure gap for underfill resin injection, then the gap can be maintained, but controlling the gap becomes difficult and short circuits may occur
Solution Approach 1:
The patent applies preliminary action by pre-forming the columnar metal layer with a predetermined height and overlap region before the bonding process. This preliminary structure ensures that the gap is automatically controlled during assembly, eliminating the need for complex real-time gap control mechanisms
Solution Approach 2:
The gap control electrode serves itself by using its own structural features (columnar shape with overlap region) to automatically maintain the required gap. The structure self-regulates the gap during the bonding process without requiring external control mechanisms
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 effectively stabilizes the gap between the semiconductor chip and the packaging substrate, preventing short circuits and enabling higher signal density and reduced substrate costs by maintaining the integrity of the solder layer and ensuring reliable bonding.
Implementation Method 1
connecting the plurality of solder-including electrodes to the plurality of wirings, by reflow heating
Implementation Method 2
heating the semiconductor chip and pressure-bonding the semiconductor chip to the packaging substrate
Implementation Method 3
injecting an underfill resin between the semiconductor chip and the packaging substrate
Implementation Method 4
detecting a load by allowing the columnar metal layer of the at least one gap control electrode and the solder resist layer to be in contact with each other
Data Source
AI summary
A semiconductor chip includes a chip body and a plurality of solder-including electrodes provided on an element-formation surface of the chip body. A packaging substrate includes a substrate body, a plurality of wirings, and a solder resist layer, in which the plurality of wirings and the solder resist layer are provided on a front surface of the substrate body. The solder resist layer is provided as a continuous layer on the front surface of the substrate body and the plurality of wirings, and has an aperture on each of the plurality of wirings. The plurality of solder-including electrodes include at least one gap control electrode. The at least one gap control electrode includes a columnar metal layer and a solder layer in order named from side on which the chip body is disposed, and includes an overlap region where the columnar metal layer and the solder resist layer overlap each other, along part or all of an aperture end of the aperture.