Direct Bonded Semiconductor Substrates With Integrated Passive Elements
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Solution Overview
Problem
Conventional three-dimensional stacked semiconductor devices require numerous additional process steps and increased fabrication costs to incorporate passive elements, such as MIM capacitor elements, due to the need for lithography, etching, and planarization, which complicates the integration of passive elements into the interconnect layer.
Innovation Solution
A semiconductor device and method that involves directly bonding two substrates with a functional film between electrodes to form a passive element, such as a MIM capacitor or resistance element, using a minimized number of additional process steps, where the functional film is made of materials like SiOx, HfOx, or high-resistance metals, and the electrodes are made of metals like aluminum, copper, or tungsten, allowing for the integration of passive elements without the need for extensive additional processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bumps are fusion bonded together to electrically connect semiconductor chips, then electrical connection between chips is achieved, but the bumps are deformed which may result in short circuits and misalignment due to thermal expansion differences
Solution Approach 1:
The patent changes the bonding temperature parameter from high temperature (around 200°C for fusion bonding) to low temperature (room temperature or below) for direct bonding. This parameter change prevents thermal expansion mismatch and bump deformation, thereby maintaining both electrical connection reliability and alignment precision without the harmful effects of conventional fusion bonding
2Productivity
If direct bonding is used to bond semiconductor chips together, then the pitch between electrodes can be shorter, but additional process steps are required to form passive elements like MIM capacitor elements
Solution Approach 1:
The patent merges the formation of passive elements (MIM capacitor elements) with the direct bonding process itself. The functional film serving as the capacitor insulating layer is formed on the chip surface before bonding, and the bonding process simultaneously achieves both chip connection and passive element formation. This integration eliminates separate lithography, etching, and planarization steps that would otherwise be required, reducing device complexity while maintaining high integration density
Solution Approach 2:
The functional film serves multiple functions: it acts as the capacitor insulating layer for passive elements, provides bonding surface preparation, and enables both electrical connection and passive element formation through a single bonding process. This multi-functionality reduces the overall number of process steps required in the fabrication sequence
3Adaptability or versatility
If new process steps are added to form passive elements in the interconnect layer, then three-dimensional stacked semiconductor devices with passive elements can be provided, but the fabrication cost and process complexity increase
Solution Approach 1:
The patent performs preliminary action by forming the functional film (capacitor insulating layer) on the chip surface before the direct bonding process. This advance preparation allows the passive elements to be formed during bonding itself, rather than requiring subsequent separate processing steps. The preliminary formation of the functional film enables versatile device functionality while simplifying the overall fabrication process and reducing costs
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 approach enables the stable and cost-effective fabrication of three-dimensional stacked semiconductor devices with integrated passive elements by reducing the number of additional process steps required, facilitating the integration of passive elements into the semiconductor chip without increasing fabrication complexity or costs.
Implementation Method 1
a functional film provided between the second surface of the second electrode and the fourth surface of the fourth electrode
Implementation Method 2
the functional film is made of materials like SiOx, HfOx, or high-resistance metals
Implementation Method 3
direct bonding of two semiconductor chips as a new bonding technique substituted for the technique for fusion bonding of bumps
Data Source
AI summary
A semiconductor device includes: a first substrate including a first surface layer that includes first and second electrodes; a second substrate including a second surface layer that includes third and fourth electrodes, and directly bonded to the first substrate such that the second surface layer is in contact with the first surface layer; and a functional film provided between the second and fourth electrodes. The first and third electrodes are bonded together so as to be in contact with each other, and the second electrode, the functional film, and the fourth electrode constitute a passive element.