Semiconductor Device Warpage Control via Metal Plate Thickness
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Solution Overview
Problem
Ceramic substrates in semiconductor devices experience warpage due to thermal expansion mismatch between metal circuit boards and ceramic substrates, leading to potential breakage, as existing designs do not adequately consider the circuit pattern and thickness ratios of the metal components.
Innovation Solution
A semiconductor device design where the metal circuit board is thicker than the metal heat-dissipation plate, with a larger surface area on the heat-dissipation plate compensating for the circuit board's volume, balancing thermal stress and preventing warpage, using materials like copper for improved thermal conductivity and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the metal circuit board is increased in thickness to reduce warpage, then the expansion amount increases due to heat, but this leads to larger warpage and potential breakage of the ceramic substrate
Solution Approach 1:
The invention changes the thickness parameters of metal components - specifically making the metal circuit board thinner than the metal heat-dissipation plate. This parameter adjustment balances the thermal expansion volumes of both metal parts, reducing the net expansion force that causes ceramic substrate warpage and breakage.
2Reliability
If the metal circuit board is simply increased in thickness without considering the circuit pattern, then the expansion amount increases, but this causes large warpage in the ceramic substrate
Solution Approach 1:
The invention optimizes the thickness parameters of metal components based on their functional requirements and thermal expansion characteristics. The metal circuit board is designed with a specific thickness range (0.3-1.0mm) that is thinner than the metal heat-dissipation plate, achieving balanced thermal expansion and reduced warpage.
Solution Approach 2:
The invention applies different thickness specifications to different metal components based on their local functions. The metal circuit board (with circuit patterns) has a different thickness than the metal heat-dissipation plate (without circuits), optimizing both electrical functionality and thermal expansion balance.
3Reliability
If the metal circuit board thickness is increased to suppress cracking, then the expansion amount increases, but this may lead to breakage of the ceramic substrate
Solution Approach 1:
The invention changes the thickness parameters to achieve balanced thermal expansion. The metal circuit board thickness is set to 0.3-1.0mm, which is thinner than the metal heat-dissipation plate, creating a balance in expansion volumes that reduces harmful thermal stress on the ceramic substrate while preventing cracking.
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 design effectively suppresses warpage and cracking in ceramic substrates, enhances heat dissipation performance, reduces the risk of breakage, and improves productivity by using copper for the metal components, while maintaining efficient thermal conductivity.
Implementation Method 1
Since the metal circuit board is greater in coefficient of thermal expansion than the ceramic substrate, the metal circuit board expands more than the ceramic substrate due to the heat produced when using the semiconductor element.
Data Source
AI summary
A semiconductor device includes a semiconductor element and a ceramic circuit substrate on which the semiconductor element is mounted. The ceramic circuit substrate includes a ceramic substrate having one surface and the other surface facing each other, a metal circuit board joined to the one surface of the ceramic substrate and electrically connected to the semiconductor element, and a metal heat-dissipation plate joined to the other surface of the ceramic substrate. The metal circuit board is greater in thickness than the metal heat-dissipation plate. A surface of the metal heat-dissipation plate on a side opposite to the ceramic substrate is larger in area than a surface of the metal circuit board on a side opposite to the ceramic substrate. Thereby, a semiconductor device capable of suppressing warpage of the ceramic substrate can be achieved.