Multi-Modal Ceramic Powder for Semiconductor Sealing
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Solution Overview
Problem
The stacked-chip multi-layered structure in semiconductor packaging faces challenges with moldability and void formation due to differences in height and increased gold wire complexity, leading to issues like air bubbles and wire deformation.
Innovation Solution
A ceramic powder with a multiple peak-frequency particle size distribution, specifically with peaks between 12-30 μm, 2-7 μm, and 0.1-0.8 μm, and a silica powder composition that can be incorporated into resin or rubber, enhancing interstice-filling and moldability by controlling viscosity and particle distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a stacked-chip multi-layered structure is used to increase packaging density, then the packaging density is improved, but the moldability deteriorates due to height differences and material flow variations causing void formation
Solution Approach 1:
The patent changes the particle size distribution parameters of the filler material, specifically using a multi-modal distribution with peaks at 3-6 μm, 8-15 μm, and 20-40 μm. This parameter optimization allows the sealing material to better adapt to the height differences in stacked-chip structures, improving flow characteristics and reducing void formation while maintaining high packaging density
Solution Approach 2:
The patent creates a composite sealing material combining epoxy resin with a specifically designed multi-modal filler composition (silica powder, alumina, titania, and zirconia in controlled ratios). This composite structure provides both the flowability needed for complex mold filling and the mechanical properties required for high-density packaging applications
2Loss of time
If the viscosity of sealing resin is reduced to control curing time, then the curing time control is improved, but the filler charging rate deteriorates leading to insufficient filling
Solution Approach 1:
The patent optimizes the particle size distribution parameters of the filler to have three distinct peaks (3-6 μm, 8-15 μm, 20-40 μm) with specific weight ratios. This parameter optimization maintains adequate viscosity for proper filler charging while allowing sufficient time for complete filling of narrow portions before curing begins
Solution Approach 2:
The patent applies different particle size ranges to different functional requirements: finer particles (3-6 μm) for narrow interstice filling, medium particles (8-15 μm) for bulk filling, and coarser particles (20-40 μm) for structural support. This local quality differentiation resolves the contradiction between viscosity control and filler charging
3Manufacturing precision
If particle size of filler is reduced to improve filling property, then the filling property is improved, but the viscosity of sealing material increases
Solution Approach 1:
The patent segments the filler particle size distribution into three distinct size ranges with peak frequencies at 3-6 μm, 8-15 μm, and 20-40 μm. This segmentation allows each particle size range to fulfill different functions: fine particles for penetrating narrow gaps, medium particles for efficient packing, and coarse particles for maintaining low viscosity, collectively resolving the contradiction between filling property and viscosity
4Adaptability or versatility
If long-spun gold wires are used for electrical connection of multiple chips, then the electrical connection capability is improved, but the wire deformation increases due to flow resistance
Solution Approach 1:
The patent optimizes the viscosity parameters of the sealing material by controlling the resin-to-filler ratio and particle size distribution. This parameter optimization reduces flow resistance during injection molding, preventing deformation of long-spun gold wires while maintaining adequate flow to reach all connection points in multi-chip configurations
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 ceramic powder composition achieves high narrow interstice-filling and excellent moldability, reducing void formation and wire deformation, even at high filling rates up to 89% by mass, improving semiconductor-sealing material performance.
Implementation Method 1
a multiple peak-frequency type particle size distribution having at least two peaks, as determined according to the laser diffraction-scattering type particle size distribution analyzer in which the maximum particle size observed for the first peak falls within the range of from 12 to 30 μm; in which the maximum particle size observed for the second peak falls within the range of from 2 to 7 μm
Implementation Method 2
as determined according to the laser diffraction-scattering type particle size distribution analyzer
Data Source
AI summary
The present invention herein provides ceramic powder which is to be incorporated into rubber or a resin and which can be used as, for instance, a semiconductor-sealing material and for the preparation of a composition excellent in the narrow interstice-filling up property and moldability. The ceramic powder has a multiple peak-frequency type particle size distribution which has at least two peaks, as determined according to the laser diffraction-scattering type particle size distribution analyzer, wherein the maximum particle size observed for the first peak falls within the range of from 12 to 30 μm; that observed for the second peak falls within the range of from 2 to 7 μm; the content of the particles having a particle size of greater than 7 μm and less than 12 μm is not more than 18% (including 0%); and wherein the ratio (F2/F1) of the frequency value F2 of the maximum particle size for the second peak to that F1 of the maximum particle size for the first peak ranges from 0.5 to 1.3.