Stacked Solder Ball Semiconductor Package with Insulating Short Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing size of solder balls in semiconductor packages to accommodate more integrated circuit chips leads to increased pitch, making it difficult to achieve a fine ball pitch and maintain the necessary distance between packages, which hinders the integration of semiconductor packages.
Innovation Solution
A semiconductor package design featuring stacked solder balls with a solder passivation layer and ring-shaped short prevention parts, where the solder passivation layer is made of materials with a higher melting point than the connection terminals, and the short prevention parts are formed from insulating materials like photo solder resist or resin-based adhesive to prevent electrical shorts and maintain the distance between packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the sizes of solder balls are increased to maintain distance between packages, then the distance between packages is improved, but the pitch is increased making it difficult to achieve fine ball pitch
Solution Approach 1:
The connection terminal is divided into multiple segments: first solder ball, second solder ball, and intermediate connection portion. This segmentation allows the vertical stacking of connection terminals, achieving fine ball pitch in the horizontal plane while maintaining adequate distance between packages through vertical arrangement.
Solution Approach 2:
The invention transitions from horizontal arrangement of solder balls to vertical stacking arrangement. By utilizing the vertical dimension (Z-axis) for stacking connection terminals, the horizontal pitch can be reduced while maintaining sufficient inter-package distance through the vertical configuration.
2Productivity
If the number of semiconductor integrated circuit chips stacked is increased to improve integration, then the integration is improved, but the distance between packages must be increased which conflicts with fine ball pitch requirement
Solution Approach 1:
The connection terminal is segmented into first solder ball, second solder ball, and intermediate connection portion with short prevention parts. This segmentation enables compact vertical stacking that accommodates more chips while maintaining fine horizontal ball pitch.
Solution Approach 2:
By stacking connection terminals vertically rather than arranging them horizontally, the invention enables increased chip integration without increasing the horizontal footprint, thus maintaining fine ball pitch while accommodating more chips.
3Manufacturing precision
If solder balls are stacked to achieve fine ball pitch, then the ball pitch is reduced, but electrical short between stacked solder balls may occur
Solution Approach 1:
An intermediate connection portion consisting of insulating material with short prevention parts is introduced between the first and second solder balls. This intermediary structure prevents electrical short while enabling the vertical stacking configuration for fine ball pitch.
Solution Approach 2:
Short prevention parts are formed in advance within the intermediate connection portion to prevent electrical short between stacked solder balls before the potential shorting issue arises during operation.
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 design allows for a fine ball pitch and increased integration by minimizing the pitch of the connection terminals while maximizing the distance between packages, enabling more semiconductor chips to be stacked without electrical shorts.
Implementation Method 1
a solder passivation layer with which a surface of at least one of the first and second solder balls is coated
Implementation Method 2
the solder passivation layer may include a metal that has a higher melting point than that of the connection terminal
Implementation Method 3
the forming of the connection terminal may include reflowing the first and second solder balls at a temperature that is higher than a melting point of the connection terminal and lower than a melting point of the solder passivation layer
Implementation Method 4
a ring-shaped short prevention part that surrounds a coupling portion between the first and second solder balls, and that prevents an electrical short of the connection terminal
Implementation Method 5
planarizing the first solder ball to form a flat surface
Data Source
AI summary
A semiconductor package includes a first package and a second package, a connection terminal disposed between the first and second packages and including a first solder ball and a second solder ball that are vertically stacked, a solder passivation layer with which a surface of at least one of the first and second solder balls is coated, and a ring-shaped short prevention part surrounding a coupling portion between the first and second solder balls.