Hybrid Bonding Surface Cleaning for Nanoparticle Leakage Control
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Solution Overview
Problem
In hybrid bonding processes, especially those involving metal-to-metal direct bonding with dielectric materials, very small conductive particles can cause signal leakage and micro-delamination due to their presence at the bonding interface, especially at submicron spacings, leading to reliability issues in microelectronic devices.
Innovation Solution
A novel cleaning process is introduced that cleans the activated surface after plasma activation but before hybrid bonding, using dilute acids, organic alkaline compounds, or megasonic agitation to physically or chemically remove nanoparticles, ensuring the surface is free from extraneous metal particles before bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning with deionized water is used after plasma activation, then the activated surface is maintained, but extraneous conductive nanoparticles remain at the bonding interface causing signal leakage
Solution Approach 1:
The patent extracts and removes extraneous conductive nanoparticles from the bonding interface using a targeted cleaning process. The cleaning solution specifically targets and removes conductive particles while preserving the activated bonding surface, thereby eliminating the harmful factor without compromising the bonding capability.
Solution Approach 2:
The patent introduces a cleaning solution as an intermediary substance between the activated surface and the bonding process. This intermediary medium carries out the particle removal function while being carefully controlled to not interfere with the subsequent bonding operation.
2Object-affected harmful factors
If additional cleaning steps are introduced after plasma activation, then nanoparticle removal is achieved, but process complexity increases
Solution Approach 1:
The patent merges the particle removal function with the existing cleaning step in the bonding process. By integrating nanoparticle removal into the conventional cleaning operation using a specially formulated cleaning solution, the process adds particle removal capability without requiring entirely separate additional steps.
Solution Approach 2:
The patent changes the parameters of the cleaning solution (composition, concentration, application method) to achieve nanoparticle removal. By modifying the cleaning solution properties rather than adding entirely new process steps, the solution removes particles while maintaining process simplicity.
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 process significantly enhances the electrical reliability of microelectronic devices by preventing signal leakage and maintaining the integrity of the bonding interface, even at fine trace pitches, by ensuring the absence of metal nanoparticles at the bonding interface.
Implementation Method 1
cleaning the surface to remove particles disposed at the surface... chemically remove nanoparticles
Implementation Method 2
megasonic agitation to physically or chemically remove nanoparticles
Data Source
AI summary
Reliable hybrid bonded apparatuses are provided. An example process cleans nanoparticles from at least the smooth oxide top layer of a surface to be hybrid bonded after the surface has already been activated for the hybrid bonding. Conventionally, such an operation is discouraged. However, the example cleaning processes described herein increase the electrical reliability of microelectronic devices. Extraneous metal nanoparticles can enable undesirable current and signal leakage from finely spaced traces, especially at higher voltages with ultra-fine trace pitches. In the example process, the extraneous nanoparticles may be both physically removed and/or dissolved without detriment to the activated bonding surface.