IC Package Substrate Pad Structure for Reduced Die Clearance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in integrated circuit (IC) package design is to reduce the die-substrate clearance to minimize the height of the IC package while maintaining effective electrical interfacing and mechanical support.
Innovation Solution
The solution involves incorporating a reduced area, additional metal pad(s) coupled to metal interconnect(s) on the substrate, which allows for a solder joint to be formed with a die interconnect, thereby controlling the clearance between the die and the substrate by adjusting the solder amount or die interconnect length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard metal pad is used to couple the die to the substrate, then reliable electrical connection is achieved, but the die-substrate clearance cannot be reduced sufficiently
Solution Approach 1:
The metal pad is segmented into two distinct pads: a first metal pad with larger cross-sectional area for mechanical support and electrical connection, and a second metal pad with reduced cross-sectional area for controlling solder flow and minimizing clearance. This segmentation allows each pad to serve its specific function optimally.
Solution Approach 2:
Different regions of the pad structure are given different properties: the first metal pad has larger area for strength and electrical connection, while the second metal pad has reduced area specifically at the location where solder contact occurs, creating local quality variation that controls solder flow and clearance.
2Reliability
If solder amount is increased to ensure reliable joint formation, then connection reliability improves, but die-substrate clearance reduction is compromised
Solution Approach 1:
The cross-sectional area parameter of the metal pad is changed by introducing a second pad with reduced area. This parameter change controls the solder flow characteristics, allowing sufficient solder for reliable joint formation while limiting excess solder that would increase clearance.
3Length of stationary object
If the metal pad cross-sectional area is reduced to minimize clearance, then die-substrate clearance is reduced, but electrical connection reliability may be compromised
Solution Approach 1:
The pad structure is segmented into two pads with different areas. The first pad maintains larger area for electrical connection reliability, while the second pad has reduced area for clearance control, thus resolving the contradiction through functional segmentation.
Solution Approach 2:
The two metal pads are merged into a single integrated pad structure that combines both functions: the first pad provides electrical connection and mechanical support, while the second pad provides clearance control. The merged structure achieves both objectives simultaneously.
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 approach effectively reduces the die-substrate clearance, thereby lowering the overall height of the IC package, while ensuring reliable electrical connections and mechanical stability.
Implementation Method 1
A solder joint(s) is employed to couple the second, additional metal pad(s) to a die interconnect(s) of the die to couple the die to the substrate
Data Source
AI summary
Integrated circuit package having a substrate employing reduced area, added metal pad(s) to metal interconnect(s) to reduce a die to a substrate clearance and related fabrication methods are disclosed. The IC package includes die interconnects coupled to first metal pad(s) of respective metal interconnects of a metallization layer of the substrate to provide support and signal routing paths. To reduce clearance between the die and the substrate and consequently the height of the IC package, a second, additional metal pad(s) having a reduced cross-sectional area from the first metal pad(s) is coupled to the first metal pad(s). Solder is employed to couple the second, additional metal pad(s) to a die interconnect(s) of the die to couple the die to the substrate. When the solder is heated to form the solder joint, the solder flows along the reduced cross-sectional area of the second, additional metal pad(s).