Vertical Die Stack With Side Grooves for Compact PCB Mounting
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Solution Overview
Problem
The increasing demand for high-capacity storage in portable consumer electronics is limited by the footprint length of semiconductor packages due to the need for offsetting dies for wire bonding, which restricts the number of dies that can be wire bonded in a standard size package.
Innovation Solution
A semiconductor device configuration where semiconductor dies are mounted vertically in a stack without offset, using metal pillars for direct electrical coupling to a printed circuit board, eliminating the need for a substrate and wire bonds, and featuring side grooves to expose electrical conductors for connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dies are offset from each other to provide access for wire bonding, then electrical connections can be made between dies and substrate, but the overall footprint length of the die stack increases
Solution Approach 1:
The patent transitions from a planar 2D wire bonding approach to a 3D vertical stacking approach with side grooves. Instead of offsetting dies horizontally to access bond pads, the invention stacks dies vertically and provides access to electrical conductors through side grooves formed in the molding compound, enabling wire bonding from the side rather than from above or below.
Solution Approach 2:
The invention segments the electrical connection path by creating separate access points through side grooves for each die in the stack. Each die's electrical conductors are accessible through individual grooves formed in the molding compound, allowing independent wire bonding connections without requiring horizontal offset between dies.
2Quantity of substance
If the number of dies in a package is increased to provide more storage capacity, then storage capacity increases, but the footprint length becomes a limiting factor
Solution Approach 1:
The patent exploits the third dimension (vertical stacking) to increase storage capacity without increasing footprint length. By stacking multiple dies vertically and providing side access through grooves, the invention enables high-density packaging where N dies can be stacked in a compact footprint, overcoming the limitation of horizontal expansion.
Solution Approach 2:
The invention implements a nested structure where multiple dies are stacked vertically within a compact package footprint. Each die is positioned above the previous one, similar to nested dolls, with side grooves providing access to electrical conductors without requiring additional horizontal space.
3Reliability
If a rigid dielectric base with conductive layer is used as substrate, then electrical connections can be established, but device complexity and manufacturing steps increase
Solution Approach 1:
The invention extracts and eliminates the rigid dielectric base substrate from the package structure. Instead of using a traditional substrate with etched conductive layers, the patent directly mounts dies to a circuit board through side grooves in the molding compound, simplifying the overall device structure while maintaining electrical connection reliability.
Solution Approach 2:
The invention changes the mounting orientation from horizontal (on a substrate plane) to vertical (stacking on edge). Dies are mounted vertically with electrical conductors accessible through side grooves, eliminating the need for a intermediate dielectric substrate and its complex conductive layer patterning.
Data Source
AI summary
A semiconductor device is vertically mounted on a medium such as a printed circuit board (PCB). The semiconductor device comprises a block of semiconductor dies, mounted in a vertical stack without offset. Once formed and encapsulated, side grooves may be formed in the device exposing electrical conductors of each die within the device. The electrical conductors exposed in the grooves mount to electrical contacts on the medium to electrically couple the semiconductor device to the medium.