Ultra-Thin Semiconductor Packaging With Coreless Warpage Resistance
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Solution Overview
Problem
Conventional semiconductor packages, especially coreless substrates, suffer from warpage issues during Surface Mount Technology (SMT) processes due to differences in thermal expansion coefficients of materials, leading to manufacturing problems and reduced performance.
Innovation Solution
The development of ultra-thin, hyper-density semiconductor packages using coreless substrate technology, die back metallization, and low temperature solder technology for ball grid array metallurgy, combined with metal pillars and pitch translation interposers, minimizes warpage by ensuring precise alignment and attachment of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If coreless substrate technology is used to reduce package thickness, then the z-height is reduced, but warpage susceptibility increases during SMT processes
Solution Approach 1:
The substrate is divided into multiple thin layers (carrier substrate, substrate layers, dielectric layers) that can be independently controlled and assembled. This segmentation allows each layer to be optimized for its specific function while collectively providing warpage resistance through precise stacking and matching of thermal expansion properties.
Solution Approach 2:
The patent modifies physical parameters including using ultra-thin substrates with controlled thickness (e.g., 25-75 micrometers), adjusting dielectric material composition to match thermal expansion coefficients, and controlling metal pillar dimensions and distribution to compensate for thermal stresses during SMT processing.
2Length of moving object
If package thickness is reduced to meet slim device requirements, then z-height decreases, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
Metal pillars serve as intermediary structures that provide precise mechanical registration and alignment between the ultra-thin substrate and the semiconductor die. These pillars act as reference features that maintain positional accuracy during assembly and soldering processes, enabling manufacturing precision despite the reduced overall package thickness.
Solution Approach 2:
The metal pillars are pre-formed on the substrate before die attachment, establishing precise alignment references in advance. The substrate layers and dielectric materials are also pre-assembled with controlled thicknesses and material properties to minimize thermal mismatch before the actual SMT process begins.
3Quantity of substance
If pitch is reduced to increase component density, then device size decreases, but warpage susceptibility increases due to finer spacing
Solution Approach 1:
The patent employs composite substrate structures combining multiple materials with complementary properties: carrier substrates providing mechanical support, thin substrate layers enabling high density, and dielectric materials with matched thermal expansion coefficients. This composite approach allows fine pitch arrangements while maintaining warpage resistance through the synergistic properties of the layered material system.
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
These packages exhibit minimal warpage, enabling ultra-thin z-heights and high die-to-package ratios, facilitating the production of compact, high-performance electronic devices with improved reliability and reduced manufacturing defects.
Implementation Method 1
SMT processes typically involve subjecting package substrates to heating and cooling which in turn create expansion and contraction of the substrate. The difference in coefficient of thermal expansion (CTE) of the various materials forming the substrate results in different rates of expansion and contraction and hence stress in the substrate.
Data Source
AI summary
Ultra-thin, hyper-density semiconductor packages and techniques of forming such packages are described. An exemplary semiconductor package is formed with one or more of: (i) metal pillars having an ultra-fine pitch (e.g., a pitch that is greater than or equal to 150 μm, etc.); (ii) a large die-to-package ratio (e.g., a ratio that is equal to or greater than 0.85, etc.); and (iii) a thin pitch translation interposer. Another exemplary semiconductor package is formed using coreless substrate technology, die back metallization, and low temperature solder technology for ball grid array (BGA) metallurgy. Other embodiments are described.