High Density Ceramic Substrate for LED Thermal Management
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Solution Overview
Problem
High power LEDs face challenges with heat dissipation due to limited thermal conductivity and coefficient of thermal expansion mismatch between substrate materials and LED chips, leading to reduced reliability and lifespan, and existing ceramic substrates require complex and time-consuming drilling processes for high-density thermal and electrical pathways.
Innovation Solution
A die structure manufacturing method involving a substrate with alternately stacked insulating material layers and thermal and electrical conductive poles, exposed on opposite surfaces, which are sintered and cut to form a substrate with high-density, solid conductive poles, eliminating the need for drilling and slurry filling, and allowing for improved thermal and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical drilling is used to create through holes in ceramic substrate for thermal and electrical pathways, then thermal and electrical conductivity is improved, but manufacturing time increases and production efficiency decreases
Solution Approach 1:
The conductive pillars are pre-formed within the ceramic substrate during the sintering process itself, rather than creating holes and filling them afterward. The green body is molded with embedded conductive materials, and during sintering, these materials are consolidated into functional conductive pathways, eliminating the need for subsequent drilling and filling operations
Solution Approach 2:
The invention combines multiple manufacturing steps (substrate formation, conductive pathway creation, and thermal/electrical conduction establishment) into a single sintering process. The conductive pillars and ceramic matrix are formed simultaneously through co-sintering, merging substrate fabrication with conductive pathway integration
2Reliability
If through holes are drilled with small pitch for high-density pathways, then thermal and electrical conductivity improves, but manufacturing complexity and time increase
Solution Approach 1:
The conductive pillars are pre-positioned and pre-formed within the green body at the desired high-density arrangement before sintering. The molding process establishes the exact pitch and positioning of conductive elements, eliminating the need for complex post-processing alignment and drilling operations
Solution Approach 2:
The invention changes the fundamental parameter of how conductive pathways are created - from post-formation (drilling and filling) to pre-formation (molding and sintering). This parameter change enables high-density pathways to be achieved through standard molding capabilities rather than complex precision drilling
3Reliability
If insulating adhesive layer is used in MCPCB for heat dissipation, then thermal conductivity improves, but coefficient of thermal expansion mismatch causes reliability issues
Solution Approach 1:
The substrate uses a composite ceramic material structure where ceramic powders (such as aluminum oxide, aluminum nitride, or silicon carbide) are sintered to form a matrix with embedded conductive pillars. This composite structure provides both high thermal conductivity and a coefficient of thermal expansion matched to LED chips, eliminating the CTE mismatch problem of MCPCB insulating layers
Solution Approach 2:
The ceramic substrate provides a homogeneous material composition throughout, with the ceramic matrix and conductive pillars forming an integrated structure. This homogeneity ensures uniform thermal and mechanical properties, including a consistent coefficient of thermal expansion that matches LED chips, preventing the peeling and cracking issues seen in layered MCPCB structures
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 method enhances thermal and electrical conductivity, simplifies the manufacturing process, and increases the density of conductive poles, improving the reliability and lifespan of high power LEDs by effectively managing heat dissipation and reducing manufacturing complexity.
Implementation Method 1
a plurality of first insulating material layers and a plurality of thermal and electrical conductive poles are alternately stacked and sintered
Data Source
AI summary
A die structure, a manufacturing method and a substrate, wherein the die structure is constituted by a chip on wafer (COW) and the substrate, and the substrate is formed by stacking and then cutting a plurality of thermal and electrical conductive poles and a plurality of insulating material layers. Moreover, the fabricating of the die structure comprises a plurality of COWs carried on a carrier board is bonded on the substrate, the plurality of COWs are in contact with the plurality of thermal and electrical conductive poles on the substrate, and then the carrier board is removed. After that, a phosphor plate is adhered on the plurality of COWs so as to form a stacked structure. Thereafter, the stacked structure is cut, thus forming a plurality of die structures having at least one COW.