Silicon Nitride-Melilite Composite for Adjustable Thermal Expansion
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Solution Overview
Problem
Current semiconductor inspection devices, such as probe cards, face challenges in achieving a thermal expansion coefficient that matches semiconductor wafers, particularly at high temperatures, due to limitations in ceramic materials like aluminum nitride and alumina, which lack adjustable thermal expansion coefficients and sufficient mechanical strength.
Innovation Solution
A silicon nitride-melilite composite sintered body is developed, comprising silicon nitride crystalline phases, melilite crystalline phases of Me2Si3O3N4, and grain boundary phases, with a melilite ratio of at least 20% to achieve a thermal expansion coefficient adjustable between 2 to 6 ppm/K and high Young's modulus, suitable for use in probe cards and semiconductor inspection devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum nitride is used as the ceramic material, then the thermal expansion coefficient is close to that of semiconductor wafer (4 ppm/K), but the thermal expansion coefficient cannot be adjusted to other values
Solution Approach 1:
The patent applies composite materials by combining silicon nitride (with lower thermal expansion coefficient of 2 ppm/K or below) and alumina (with higher thermal expansion coefficient of 6 ppm/K or above) to create a composite ceramic substrate that achieves an adjustable average thermal expansion coefficient between 2-6 ppm/K, resolving the contradiction between thermal expansion matching and adjustability
2Reliability
If silicon nitride is used as the ceramic material, then the thermal expansion coefficient is low (2 ppm/K or below), but it does not provide sufficient mechanical strength for large-scaled substrates
Solution Approach 1:
The patent uses composite materials combining silicon nitride and alumina, where alumina contributes higher mechanical strength and silicon nitride provides lower thermal expansion coefficient, achieving both requirements simultaneously through material composition design
3Strength
If alumina is used as the ceramic material, then the mechanical strength is high, but the thermal expansion coefficient is too high (6 ppm/K or above)
Solution Approach 1:
The patent applies composite materials by combining alumina (high strength, high thermal expansion) with silicon nitride (lower thermal expansion) to create a composite that maintains the mechanical strength of alumina while reducing the overall thermal expansion coefficient to the desired 2-6 ppm/K range
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 silicon nitride-melilite composite sintered body provides high mechanical strength, adjustable thermal expansion, and reliable inspection and production capabilities for semiconductor wafers across varying temperatures, enhancing the reliability of semiconductor inspection and production processes.
Implementation Method 1
the average thermal expansion coefficient that is arbitrarily adjustable in a range of 2 to 6 ppm/K according to the demand characteristics of the device
Implementation Method 2
silicon nitride-melilite composite sintered body
Data Source
AI summary
A silicon nitride-melilite composite sintered body in accordance with the invention includes silicon nitride and a melilite Me2Si3O3N4, where Me denotes a metal element combining with silicon nitride to generate the melilite. The silicon nitride-melilite composite sintered body contains Si in a range of 41 to 83 mole percent in Si3N4 equivalent and Me in a range of 13 to 50 mole percent in oxide equivalent. The silicon nitride-melilite composite sintered body has an average thermal expansion coefficient that is arbitrarily adjustable in a range of 2 to 6 ppm/K at temperatures of 23 to 150° C. The silicon nitride-melilite composite sintered body has a high Young's modulus, a high mechanical strength, and excellent sintering performance. A device used for inspection of semiconductor in accordance with the invention utilizes such a silicon nitride-melilite composite sintered body.