Bonded Passive Substrate Integration for CMOS Reliability
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Solution Overview
Problem
Current semiconductor device fabrication methods face challenges in integrating passive circuits with active circuits without compromising the performance and reliability of the active circuits, particularly due to issues like metal contamination and the limitations of existing capacitor designs in achieving high capacitance and breakdown voltage simultaneously.
Innovation Solution
The integration of passive circuits, such as deep trench capacitors, comb-type capacitors, Schottky diodes, and resistors, in a second substrate bonded to a CMOS chip, using semiconductor material with conductive through vias and low-temperature processes to avoid contamination and enhance performance, allowing for higher capacitance and breakdown voltage without affecting the active circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Schottky diodes are formed in CMOS processes with high temperatures, then the passive circuits can be integrated with active circuits, but thermal interference and metal contamination negatively impact the performance and reliability of active circuits
Solution Approach 1:
The device is divided into two separate substrates: a first substrate containing active circuits and a second substrate containing passive circuits. This segmentation allows each substrate to be optimized independently, preventing thermal interference and metal contamination from affecting both circuit types simultaneously while maintaining integration through bonding and conductive vias.
Solution Approach 2:
Passive circuits are extracted from the first substrate and placed on a separate second substrate. This extraction removes the source of thermal interference and metal contamination from the active circuits while maintaining electrical connectivity through conductive vias that pass through the first substrate to connect to the passive circuits on the second substrate.
2Device complexity
If passive circuits are integrated on the same substrate as active circuits, then device complexity is reduced, but thermal interference and metal contamination occur
Solution Approach 1:
The device structure is segmented into two substrates to physically separate active and passive circuits. This segmentation reduces device complexity by allowing standardized bonding processes while eliminating harmful thermal and contamination effects that would occur with full integration on a single substrate.
Solution Approach 2:
The first substrate acts as an intermediary between the active circuits and the passive circuits on the second substrate. Conductive vias pass through the first substrate to establish electrical connections, allowing integration benefits while maintaining physical separation to avoid thermal interference and metal contamination.
3Ease of manufacture
If Schottky diodes are formed using high temperature CMOS processes, then manufacturing is simplified, but the active circuits performance deteriorates due to thermal interference
Solution Approach 1:
The manufacturing process is segmented into two independent sequences: one for forming active circuits on the first substrate and another for forming passive circuits on the second substrate. This allows Schottky diodes to be formed using high-temperature processes on the second substrate without exposing the active circuits on the first substrate to thermal interference.
Solution Approach 2:
Active circuits are formed on the first substrate before the passive circuits are formed on the second substrate. This preliminary action protects the active circuits from subsequent high-temperature processing steps used to form Schottky diodes, as the passive circuits are already isolated on their own substrate.
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 creation of semiconductor devices with improved performance and reliability by providing high capacitance and breakdown voltage while minimizing the impact on the active circuits, and allows for the formation of various passive circuits like ESD circuits and charge pumps, enhancing the overall functionality of the semiconductor device.
Implementation Method 1
using bonding techniques like fusion bonding
Data Source
AI summary
A semiconductor device includes a first substrate having opposite first and second sides, a first conductive layer on the first side of the first substrate, and a second substrate having opposite first and second sides. The second side of the second substrate is bonded to the first side of the first substrate. The second substrate includes a semiconductor material, and at least one circuit element electrically coupled to the first conductive layer. The at least one circuit element includes at least one of a Schottky diode configured by the semiconductor material and a first contact structure, a capacitor having a first electrode of the semiconductor material, or a resistor of the semiconductor material.