Semiconductor Package Oxide Layer Structure for Void-Free Wafer Bonding
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Solution Overview
Problem
The bonding process of silicon wafers often results in voids on the bonding joint surface due to H2O generation during surface treatment and heat treatment, leading to delamination issues, which compromises the reliability of the wafer bonding.
Innovation Solution
A semiconductor package design that includes multiple insulating layers with varying silicon concentrations (20 wt% to 50 wt%) and thicknesses, where the first insulating layer with a higher silicon concentration is bonded to a second substrate, and a thinner second insulating layer with a lower silicon concentration is formed between them, inhibiting void formation by combining silicon oxide and H2O by-products during annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional insulating materials with low silicon content (<20 wt%) are used for wafer bonding, then the material cost and processing ease are improved, but voids form on the bonding joint surface due to H2O generation during heat treatment, leading to delamination and reduced reliability
Solution Approach 1:
The insulating layer is segmented into multiple layers with different silicon concentrations. The first insulating layer has a first silicon concentration (20-50 wt%), and the second insulating layer has a second silicon concentration (5-20 wt%), which is lower than the first. This segmentation allows each layer to perform its specific function: the higher silicon concentration layer prevents void formation, while the lower silicon concentration layer maintains bonding reliability.
Solution Approach 2:
Different regions of the insulating structure have different silicon concentrations tailored to their specific functions. The first insulating layer in contact with the substrate has higher silicon concentration (20-50 wt%) to prevent void formation at the bonding interface, while the second insulating layer has lower silicon concentration (5-20 wt%) to maintain overall bonding reliability. This local quality optimization resolves the contradiction between preventing voids and maintaining bonding strength.
2Object-affected harmful factors
If the silicon concentration in the insulating layer is increased to prevent void formation, then void prevention capability is improved, but the material composition complexity and manufacturing difficulty increase
Solution Approach 1:
The silicon concentration parameter is changed across different insulating layers to optimize performance. The first insulating layer has silicon concentration of 20-50 wt% to prevent void formation, while the second insulating layer has silicon concentration of 5-20 wt%. By controlling the silicon concentration parameter in each layer, the patent achieves effective void prevention while maintaining manufacturability through standard semiconductor fabrication processes.
3Reliability
If a single thick insulating layer is used, then the structural simplicity is maintained, but voids form during bonding due to H2O generation, compromising bonding reliability
Solution Approach 1:
The insulating structure is segmented into multiple layers with different silicon concentrations rather than using a single thick layer. The first insulating layer (higher silicon concentration) and second insulating layer (lower silicon concentration) work together to prevent void formation while maintaining appropriate total insulation thickness. This segmentation resolves the contradiction between reliability and material quantity.
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 enhances the bonding reliability by preventing voids on the bonding joint surface, thereby improving the structural integrity and reliability of the semiconductor package.
Implementation Method 1
combining silicon oxide and H2O by-products during annealing
Implementation Method 2
combining silicon oxide and H2O by-products
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A semiconductor package includes a first substrate including silicon, a first insulating layer in contact with the first substrate, the first insulating layer including silicon oxide, the first insulating layer having a first concentration of silicon, a second insulating layer in contact with the first insulating layer, the second insulating layer including silicon oxide, the second insulating layer having a second concentration of silicon, the second concentration lower than the first concentration, and a structure on the second insulating layer. The first concentration is a ratio of a weight of silicon in the first insulating layer to a total weight of the first insulating layer, the second concentration is a ratio of a weight of silicon in the second insulating layer to a total weight of the second insulating layer, and the first concentration is in a range from 20 wt% to 50 wt%.