Semiconductor Bonding Pad Structure for Dishing-Resistant Chip Bonding
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Solution Overview
Problem
The bonding process of semiconductor chips with miniaturized connection pads faces challenges due to dishing issues, leading to defects and reduced bonding strength, particularly with metal materials like copper.
Innovation Solution
A semiconductor package design incorporating a bonding structure with a conductive barrier layer and pad metal layer, where the conductive barrier layer extends horizontally on the edge of the pad metal layer, preventing copper diffusion and ensuring strong bonding between pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If connection pads are miniaturized to improve integration density, then storage capacity and performance improve, but dishing occurs during bonding process leading to defects
Solution Approach 1:
The patent applies preliminary action by forming a protective structure (bonding insulating layer with recessed bonding pad and conductive barrier layer extension) on the connection pad before the bonding process. This pre-formed structure prevents copper diffusion and dishing during subsequent bonding, thereby maintaining pad integrity and preventing defects while allowing miniaturization.
Solution Approach 2:
The patent introduces an intermediary structure consisting of the bonding insulating layer with a recessed bonding pad and an extended conductive barrier layer. This intermediary protects the copper connection pad from direct exposure and diffusion during bonding, enabling miniaturized pads to bond reliably without dishing defects.
2Quantity of substance
If connection pad size is reduced to increase chip capacity, then storage capacity improves, but bonding strength decreases due to dishing
Solution Approach 1:
The recessed bonding pad structure and extended conductive barrier layer are formed in advance before bonding. This preliminary configuration ensures that even miniaturized pads maintain sufficient bonding area and strength by preventing dishing during the bonding process, thereby preserving bonding strength while enabling reduced pad size for higher chip capacity.
3Reliability
If copper material is used in connection pads to improve conductivity, then electrical performance improves, but dishing occurs during bonding process
Solution Approach 1:
The bonding insulating layer with recessed bonding pad and extended conductive barrier layer serves as an intermediary that protects the copper material during bonding. This structure prevents copper diffusion while maintaining the electrical conductivity benefits of copper, thereby preserving manufacturing precision in the bonding process.
Solution Approach 2:
The patent extracts the copper material from direct exposure at the bonding interface by recessing it within the bonding insulating layer. Only the necessary conductive barrier layer extension remains at the interface, preventing copper-related dishing while maintaining electrical functionality through the barrier layer's conductivity.
4Productivity
If bonding process is performed with miniaturized pads to increase device density, then productivity improves, but defect rate increases due to dishing
Solution Approach 1:
The protective bonding insulating layer structure with recessed pad and extended barrier layer is formed in advance, enabling miniaturized pads to undergo bonding without dishing defects. This preliminary protection allows high device density to be achieved while maintaining low defect rates.
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 prevents defects in the bonding process by acting as a diffusion barrier, securing sufficient bonding strength between semiconductor chips despite potential misalignment and reducing void formation at the copper-oxide interface.
Implementation Method 1
the first conductive barrier layer may include a horizontal extension portion extending on an edge of an upper surface of the first pad metal layer
Data Source
AI summary
A semiconductor package includes a first semiconductor chip including a first semiconductor device, a second semiconductor chip including a second semiconductor device, and a bonding structure between the first and second semiconductor chips, the bonding structure including a first bonding pad, a first bonding insulating layer, a second bonding pad in contact with the first bonding pad, and a second bonding insulating layer in contact with the first bonding insulating layer. The first bonding pad may include a first pad metal layer and a first conductive barrier layer surrounding the first pad metal layer, and the first conductive barrier layer may include a horizontal extension portion extending on an edge of an upper surface of the first pad metal layer.