Semiconductor Package Pad Structure for Non-Wet Bump Bonding
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Solution Overview
Problem
Current semiconductor packages face challenges in achieving optimal electrical properties and preventing non-wet phenomena due to the initial contact area between bumps and pad structures, which affects the reliability and performance of the package.
Innovation Solution
The semiconductor package design includes a pad structure with a first top surface at a higher level and a second top surface at a lower level, connected by a connection surface, and a dielectric structure with a second part that is coplanar with the via structure, reducing the initial contact area and increasing the force applied by the bump, thereby mitigating non-wet phenomena and enhancing electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pad structure has a large initial contact area with the bump, then the electrical connection is more stable, but the bump cannot penetrate the adhesion layer effectively, causing non-wet phenomena
Solution Approach 1:
The pad structure is designed with non-uniform thickness, creating different contact characteristics in different regions. The first portion has greater thickness to provide initial penetration force, while the second portion has reduced thickness to ensure stable electrical connection after penetration, thus resolving the contradiction between penetration capability and connection stability.
Solution Approach 2:
The solution transitions from considering only the horizontal contact area to incorporating the vertical dimension by varying the pad structure thickness in the vertical direction. This dimensional change allows the pad to provide both penetration force (through greater thickness at the first portion) and stable connection (through reduced thickness at the second portion) simultaneously.
2Force
If the pad structure has greater thickness to increase penetration force, then the bump can penetrate the adhesion layer better, but the electrical connection stability is reduced
Solution Approach 1:
The pad structure implements local quality variation by having different thicknesses in different portions. The first portion has greater thickness to generate sufficient penetration force, while the second portion has reduced thickness to maintain electrical connection stability, thus resolving the contradiction between force and reliability.
Solution Approach 2:
The pad structure is segmented into at least two portions with different thickness characteristics. This segmentation allows each portion to fulfill different functions: the first portion provides penetration force while the second portion ensures stable electrical connection, resolving the contradiction between force and reliability.
3Object-generated harmful factors
If the dielectric structure is positioned to reduce initial contact area, then non-wet phenomena are mitigated, but the electrical properties may be affected
Solution Approach 1:
The dielectric structure is positioned to expose specific portions of the pad structure while covering others, creating local quality differences. This selective exposure allows the first portion to have reduced contact area for better penetration while the second portion maintains adequate contact for electrical properties, resolving the contradiction between mitigating non-wet phenomena and maintaining electrical reliability.
Data Source
AI summary
A semiconductor package includes a substrate, a dielectric structure disposed on the substrate, a via structure that penetrates the substrate and the dielectric structure, and a pad structure that is in contact with the via structure. The dielectric structure includes a first part and a second part disposed on the first part. The second part of the dielectric structure is disposed between the via structure and the pad structure. A top surface of the second part of the dielectric structure is coplanar with a top surface of the via structure.