Stacked IC Die Surface Protection for Residue-Free Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for removing processing residue from semiconductor dies and wafers are inadequate, as they often fail to completely remove thick residues without damaging underlying conductive layers, leading to poor bonding and reduced device yield.
Innovation Solution
Applying sacrificial protective layers to semiconductor surfaces before processing, followed by selective etching to remove residue without damaging underlying layers, using room-temperature or near-room-temperature processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional high-temperature wet etching or plasma ashing is used to remove thick processing residue, then residue removal is improved, but underlying conductive layers are damaged
Solution Approach 1:
A sacrificial protective layer is applied to the conductive interconnect layer before bonding operations. This preliminary protective action prevents direct exposure of the conductive layer to harsh etching or plasma processes, allowing aggressive residue removal without damaging the underlying copper or other conductive materials.
Solution Approach 2:
The sacrificial protective layer acts as an intermediary between the residue removal process and the conductive interconnect layer. It absorbs the harmful effects of wet etchants and plasma exposure, protecting the conductive layer while enabling complete residue removal. The protective layer is designed to be selectively removed after serving its protective function.
2Productivity
If stacked die arrangements are used to increase device density, then space utilization is improved, but particle contamination between dies increases
Solution Approach 1:
The sacrificial protective layer is designed as a disposable, temporary component that is applied before bonding and then completely removed. This inexpensive, temporary layer protects the critical die surfaces from particle contamination during handling and bonding operations in stacked arrangements, and is subsequently discarded to leave clean bonding surfaces.
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
Effectively removes residue while preserving the integrity of underlying layers, enhancing bonding quality and device yield, particularly in high-tolerance stacking methods like ZIBOND® and DBI®, by ensuring minimal surface roughness and particle contamination.
Implementation Method 1
wet etching the surface of the device to remove the sacrificial layers and residue
Data Source
AI summary
Representative implementations provide techniques for processing integrated circuit (IC) dies and related devices, in preparation for stacking and bonding the devices. The disclosed techniques provide removal of processing residue from the device surfaces while protecting the underlying layers. One or more sacrificial layers may be applied to a surface of the device during processing to protect the underlying layers. Processing residue is attached to the sacrificial layers instead of the device, and can be removed with the sacrificial layers.