Low Profile USB Flash Memory Device Using Wire Bonded SIP
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Solution Overview
Problem
Conventional USB memory devices have a large thickness due to the use of TSOP packages, which limits their portability and integration in compact electronic devices.
Innovation Solution
The USB flash memory device integrates both the memory portion and USB connector on the same substrate, with semiconductor die wire bonded in a System in Package (SIP) configuration, eliminating the need for encapsulated TSOP packages and reducing the overall thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If TSOP packages are used for memory and controller, then the device can be manufactured using conventional processes, but the overall thickness becomes large
Solution Approach 1:
The patent merges the memory die and controller die into a single integrated package structure, eliminating the need for separate TSOP packages. The memory die is mounted directly on the package substrate and wire-bonded to the controller die, which is also mounted on the same substrate. This consolidation reduces the overall thickness while maintaining conventional manufacturing processes.
Solution Approach 2:
The patent transitions from a vertical stacking approach with multiple TSOP packages to a planar integration approach where both memory and controller coexist on the same substrate plane. This dimensional reorganization eliminates the height accumulation of stacked packages while preserving manufacturing simplicity.
2Reliability
If TSOP packages with overmolding are used, then the memory portion is sealed and protected, but the device thickness increases
Solution Approach 1:
The patent extracts the protective encapsulation function from the thick TSOP package structure and applies it selectively only to the necessary components. The molding compound encapsulates only the memory die and controller die mounted on the substrate, rather than enclosing entire TSOP packages, thereby reducing overall thickness while maintaining protection.
3Ease of manufacture
If multiple separate components are mounted on a PCB, then the device can be assembled using standard techniques, but the overall device size and thickness increase
Solution Approach 1:
The patent combines multiple separate components (memory die, controller die, and passive components) onto a single package substrate using standard mounting and wire-bonding techniques. This consolidation integrates functions that would otherwise require separate PCB-mounted components, reducing overall device volume while maintaining assembly ease.
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 results in a low-profile USB flash memory device with a thickness of less than 1 mm, enhancing portability and enabling both removable and embedded applications, including permanent affixation to a host device's motherboard.
Implementation Method 1
The memory die and controller die are wire bonded to contact pads on the same substrate
Implementation Method 2
solder bumps may be provided on the USB pins so that the device may be permanently affixed within the host device by mating the solder bumps with contact pads on the host device motherboard and then curing the solder bumps in a reflow process
Data Source
AI summary
A low profile USB flash memory device, and methods of forming same, are disclosed. The USB flash memory device includes an integrated circuit memory portion and a USB connector. The memory portion and the USB connector may be integrally formed on the same substrate. The USB flash memory device includes a substrate on which is mounted one or more flash memory die, a controller die, passive components and an LED for indicating when the memory is being accessed. In contrast to prior art USB memory devices which used TSOP packages mounted on a printed circuit board, the semiconductor die of the present invention are affixed to the substrate and wire bonded in a SIP configuration. Omitting the encapsulated TSOP packages allows a reduction in the overall thickness of the USB flash memory device.