Semiconductor Package Bimetal Substrate Stress Engineering
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Solution Overview
Problem
The mobility of carriers in semiconductor memory devices decreases with increasing temperature, leading to reduced operational current due to lattice interference in the channel region.
Innovation Solution
A semiconductor package design that includes a supporting substrate with a bimetal structure, which bends in response to temperature increases, applying tensile stress to the channel regions of the semiconductor chip, thereby compensating for the reduced carrier mobility. This design utilizes a bimetal with different thermal expansion coefficients and a compressing member to enhance bending and stress application without external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the temperature of the semiconductor chip is increased, then the operational speed may be improved, but the mobility of carriers decreases due to lattice interference
Solution Approach 1:
The patent changes the physical state of the channel region by applying mechanical stress through substrate bending. This stress parameter change modifies the band structure and carrier scattering mechanisms, allowing high-speed operation while maintaining carrier mobility despite temperature increases
Solution Approach 2:
The patent utilizes differential thermal expansion between the semiconductor substrate and the supporting substrate. As temperature increases, the supporting substrate expands at a different rate, causing controlled bending that applies tensile stress to the channel region, thereby compensating for thermal degradation of carrier mobility
2Productivity
If the temperature is increased to improve operational speed, then data processing rate may be improved, but operational current is reduced due to decreased carrier mobility
Solution Approach 1:
The patent applies mechanical stress as an additional control parameter to the semiconductor device. This stress parameter modification enables the device to maintain high carrier mobility and operational current even at elevated temperatures, thus preserving both data processing rate and power efficiency
Solution Approach 2:
The patent applies preliminary mechanical stress to the channel region before thermal effects fully degrade carrier mobility. This pre-applied stress creates a favorable energy band structure that counteracts the harmful effects of temperature increase, maintaining operational current while enabling high-speed data processing
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
The applied tensile stress widens the gap between lattice structures, improving carrier mobility and increasing the operational current of the semiconductor chip, even at elevated temperatures.
Implementation Method 1
The supporting substrate may include a bimetal including a first metal plate and a second metal plate on the first metal plate. The second metal plate may be between the first metal plate and the semiconductor chip, and the first and second metal plates each have a width that is greater than a width of the semiconductor substrate. The first metal plate may have a first coefficient of thermal expansion and the second metal plate may have a second coefficient of thermal expansion that may be higher than the first coefficient of thermal expansion.
Implementation Method 2
The supporting substrate may include a bimetal including a first metal plate and a second metal plate on the first metal plate
Implementation Method 3
The compressing member may be configured to expand in response to the temperature increase, to thereby compress and bend the supporting substrate in response to the temperature increase
Data Source
AI summary
A semiconductor package includes a semiconductor chip including a semiconductor substrate and a plurality of cell transistors arranged on the semiconductor substrate. Channel regions of the cell transistors have channel lengths that extend in a first direction, and the package further includes a supporting substrate having an upper surface on which the semiconductor chip is affixed. The supporting substrate is configured to bend in response to a temperature increase in a manner that applies a tensile stress to the channel regions of the semiconductor chip in the first direction. Related methods are also disclosed.