Clipped Dielectric Layer for Conductive Pillar Stability
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Solution Overview
Problem
The reduction in diameter of tall pillars in semiconductor packages leads to weakened bonding strength between the pillars and the dielectric layer, causing pillars to collapse during photoresist stripping, necessitating a new semiconductor package structure to enhance bonding strength.
Innovation Solution
A semiconductor package structure with a clipped dielectric layer, where a pad is partially embedded in the dielectric layer, and a conductive structure with a portion outside and partially embedded in the layer, forming a clip that enhances bonding strength by reducing stress on the conductive structure during photoresist stripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the diameter of tall pillars is reduced to increase the number of I/O terminals, then the number of I/O terminals increases, but the bonding strength between the pillars and the dielectric layer becomes weaker
Solution Approach 1:
The dielectric layer is segmented by creating a opening that exposes only a portion of the pad, rather than completely enclosing the pillar. This segmentation allows the conductive structure to extend outside the dielectric layer while maintaining bonding strength through the exposed pad area.
Solution Approach 2:
The conductive structure is designed to extend in multiple dimensions: vertically through the dielectric layer and horizontally outside the dielectric layer. This dimensional extension allows the pillar to maintain structural integrity outside the dielectric while still forming bonds within the dielectric layer.
2Quantity of substance
If the diameter of tall pillars is reduced, then more pillars can be accommodated, but the pillars become prone to collapse during photoresist stripping
Solution Approach 1:
The pad is pre-configured with an opening that strategically exposes the pad before the photoresist stripping process. This preliminary configuration provides structural support to the conductive structure during the subsequent photoresist stripping operation, preventing collapse.
Solution Approach 2:
The exposed pad acts as an intermediary structural element that provides mechanical support to the conductive structure during the photoresist stripping process. The pad bridges the gap between the conductive structure and the substrate, preventing collapse during manufacturing.
3Strength
If the conductive structure is completely embedded in the dielectric layer, then bonding strength is maximized, but the aspect ratio is limited and manufacturing flexibility is reduced
Solution Approach 1:
The conductive structure is segmented into two portions: one embedded in the dielectric layer for bonding and one extending outside for additional functionality. The dielectric layer is also segmented with an opening to accommodate this configuration.
Solution Approach 2:
The conductive structure serves multiple functions: it provides electrical connection through the embedded portion and offers structural support and additional connectivity through the external portion. This multi-functionality increases manufacturing flexibility without compromising bonding strength.
Data Source
AI summary
A substrate structure and a semiconductor package structure are provided. The substrate structure includes a first dielectric layer, a pad and a conductive structure. The first dielectric layer has a first surface and a second surface opposite to the first surface. The pad is adjacent to the first surface and at least partially embedded in the first dielectric layer. The first dielectric layer has an opening exposing the pad, and a width of the opening is less than a width of the pad. The conductive structure is disposed on the pad and composed of a first portion outside the opening of the first dielectric layer and a second portion embedded in the opening of the first dielectric layer. The first portion has an aspect ratio exceeding 1.375.