IPD Fabrication via Backside TSV and Thinned Substrate
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Solution Overview
Problem
Current methods for fabricating integrated passive devices (IPDs) face challenges in achieving efficient electrical connections to passive components embedded in insulator materials on semiconductor substrates, particularly in reducing substrate thickness while maintaining mechanical support and ensuring reliable interconnect access.
Innovation Solution
The method involves grinding the backside of a semiconductor substrate to reduce its thickness while maintaining a mechanical support ring, and forming a tapered through-substrate via (TSV) from the backside to access passive components embedded in insulator material, with a copper layer providing electrical connection through the TSV to the embedded device terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the substrate thickness is reduced to improve IPD density and electrical performance, then the mechanical support and structural integrity deteriorate
Solution Approach 1:
The substrate is functionally segmented into two regions: a thinned central region for electrical performance and a thicker peripheral mechanical support ring for structural integrity. This segmentation allows each region to optimize its thickness for its specific function without compromising the other.
Solution Approach 2:
Different thicknesses are applied to different locations of the substrate. The central region is thinned to improve electrical performance, while the peripheral region maintains greater thickness for mechanical support. This local differentiation resolves the contradiction by allowing each area to have the quality it needs.
2Reliability
If conventional via formation methods are used to access embedded passive components, then the manufacturing complexity and difficulty increase
Solution Approach 1:
Instead of forming vias from the front surface where passive components are embedded, the method inverts the approach by forming vias from the back surface of the substrate. This allows direct access to the embedded components through the substrate thickness, simplifying the via formation process and reducing manufacturing complexity.
Solution Approach 2:
The back surface of the substrate is prepared and vias are formed in advance before final assembly. This preliminary action of creating access paths from the back surface simplifies subsequent connection steps and reduces overall fabrication difficulty.
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 efficient electrical connection to passive components, allowing for reduced substrate thickness, improved mechanical support, and enhanced interconnect access, facilitating the integration of IPDs in electronic circuit packages with improved performance and density.
Implementation Method 1
a copper layer providing electrical connection through the TSV to the embedded device terminals
Data Source
AI summary
A method for making an integrated passive device (IPD) die includes grinding a backside of a semiconductor substrate to reduce a thickness of a central portion of the semiconductor substrate while leaving a mechanical support ring on an outer portion of the substrate, and forming a through-substrate via (TSV) from the backside of the substrate. The TSV defines interconnect access to at least one passive component embedded in an insulator material disposed on a front surface of the semiconductor substrate. The substrate has a thickness less than three-quarters of an original thickness of the substrate.