Multichip Module Stacked Substrates Back-Surface Grounding
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Solution Overview
Problem
Existing multichip modules face challenges in mounting semiconductor chips with electrodes on both surfaces, particularly in stabilizing the electric potential of Silicon On Insulator (SOI) type chips, which require grounding on the back-surface while maintaining the functionality and downsizing requirements for compact electronic devices.
Innovation Solution
A multichip module configuration involving multiple substrates with conductive vias and wiring connections allows for the electrical grounding of semiconductor chips on both surfaces, using a first substrate with signal wiring and a second substrate with ground wiring, and a third substrate for stabilizing the electric potential, enabling the connection of both surfaces to the module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-substrate mounting method is used, then the structure is simple, but the back-surface of the semiconductor chip cannot be electrically grounded
Solution Approach 1:
The mounting structure is divided into multiple substrates (first substrate, second substrate, and third substrate) stacked in the thickness direction. Each substrate performs a specific function: the first substrate provides signal wiring, the second substrate provides ground wiring, and the third substrate stabilizes electric potential. This segmentation allows the back-surface grounding requirement to be met while maintaining structural organization.
Solution Approach 2:
The invention transitions from a planar single-substrate mounting to a three-dimensional stacked multi-substrate configuration. By utilizing the thickness direction (vertical dimension), the patent enables electrical connection to both the front surface (via first substrate) and back surface (via second and third substrates) of the semiconductor chip, resolving the grounding issue without excessive horizontal complexity.
2Reliability
If multiple substrates are stacked to enable back-surface grounding, then electrical potential stability is improved, but manufacturing complexity increases
Solution Approach 1:
The substrates are prepared in advance with pre-formed wiring patterns and mounting surfaces before assembly. The first substrate is prepared with signal wiring, the second substrate with ground wiring, and the third substrate with additional grounding capability. This preliminary preparation of each substrate reduces the complexity of the actual assembly process, as the components are ready-to-mount with their electrical pathways already established.
Solution Approach 2:
The multi-substrate structure serves multiple functions simultaneously: signal transmission (first substrate), grounding (second substrate), and electric potential stabilization (third substrate). This multi-functionality is achieved through a standardized stacking architecture that can be applied to various semiconductor chip configurations, reducing the need for custom manufacturing solutions for different grounding requirements.
3Adaptability or versatility
If conventional mounting is used, then the device size is smaller, but the functionality for dual-surface electrode connection is limited
Solution Approach 1:
By stacking substrates in the thickness direction rather than expanding horizontally, the invention enables dual-surface electrode connection (front and back surfaces of the chip) without significantly increasing the overall module volume. The vertical stacking utilizes the Z-axis dimension, allowing compact integration while providing the necessary adaptability for chips requiring both surfaces to be electrically connected.
Solution Approach 2:
The multiple substrates are nested in a compact stacked configuration where the first substrate, second substrate, and third substrate are positioned one above another in the thickness direction. This nesting arrangement allows the multi-functional grounding and signaling structure to be integrated within a compact volume, accommodating the dual-surface connection requirement without excessive space consumption.
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 configuration effectively grounds the back-surface of semiconductor chips, enhancing the operational stability and compatibility with downsizing requirements for compact electronic devices by ensuring reliable electrical connections across multiple surfaces.
Implementation Method 1
a second wiring (25C) provided to a fourth mounting surface... is electrically connected to the second surface and stabilizes an electric potential of the second surface
Data Source
AI summary
A multichip module provided with a first substrate, a first semiconductor chip, a second substrate and a third substrate. The first semiconductor chip has a first surface provided with a first electrode and a second surface mounted on the first substrate so that the first wiring of a first mount surface of the first substrate is electrically connected to the first electrode. The second substrate has a second mounting surface and a third mounting surface bonded to the first substrate so that the second mounting surface is opposed to the first mounting surface. The third substrate has a fourth mounting surface provided with a second wiring and a fifth mounting surface bonded to the second silicon substrate so that the fourth mounting surface is opposed to the third mounting surface and is mounted with the first semiconductor chip so that the second wiring is electrically connected to the second surface.