Semiconductor Interposer Stress Layer Layout for Warpage Control
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Solution Overview
Problem
Semiconductor wafers and packages experience warpage due to differences in thermal expansion coefficients, leading to reliability issues during manufacturing and high-temperature processes.
Innovation Solution
An interposer with a base layer, interconnect structure, and protection layers that include compressive stress in the insulating and protection layers to counteract tensile stress from the metal interconnect pattern and conductive pads, adjusting the volume ratio of conductive pads to the metal interconnect pattern and applying compressive stress to control warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of semiconductor wafer or interposer is increased, then the productivity and functionality are improved, but warpage occurs due to difference in coefficients of thermal expansion
Solution Approach 1:
The patent applies parameter changes by introducing compressive stress layers with specific thickness ratios (10-30% of total interposer thickness) and controlling stress magnitudes (500-2000 MPa) to counteract thermal expansion differences. This allows larger interposers to maintain dimensional stability despite increased size-induced warpage tendencies.
Solution Approach 2:
The patent uses composite material structures by combining base layer materials (silicon, glass, ceramic) with protective layers having different thermal expansion coefficients. The multi-layer composite structure (base layer + compressive stress layers) creates internal stress balance that compensates for CTE mismatches between different components.
2Stability of the object's composition
If compressive stress is applied to control warpage, then the stability and shape control are improved, but the device complexity increases due to additional layers and stress management
Solution Approach 1:
The patent applies local quality by placing compressive stress layers only at specific locations (upper and/or lower surfaces) rather than uniformly throughout the entire interposer. The thickness of these layers is locally optimized (10-30% of total thickness) to provide stress counterbalance only where needed for warpage control.
Solution Approach 2:
The patent segments the interposer into distinct functional layers: base layer, compressive stress layers, and protective layers. This segmentation allows independent optimization of each layer's properties (material composition, thickness, stress characteristics) to manage overall warpage while maintaining manufacturing feasibility.
3Stability of the object's composition
If the thickness of protection layer is increased, then the warpage control is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies partial action by using relatively thin compressive stress layers (10-30% of total interposer thickness) rather than thick layers. This partial thickness is sufficient to provide the necessary stress counterbalance for warpage control while avoiding the excessive thickness that would demand ultra-precise manufacturing tolerances.
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 interposer effectively reduces warpage across various temperature ranges, enhancing the reliability of semiconductor packages by maintaining a stable shape and improving signal and power integrity.
Implementation Method 1
At least one of the insulating layer and the first lower protection layer have compressive stress
Implementation Method 2
warpage may occur in the interposer and/or the semiconductor package due to a difference between coefficients of thermal expansion (CTE) of components forming the interposer or the semiconductor package
Data Source
AI summary
An interposer includes a base layer including a first surface and a second surface that are opposite to each other. An interconnect structure is disposed on the first surface. The interconnect structure includes a metal interconnect pattern and an insulating layer surrounding the metal interconnect pattern. A first lower protection layer is disposed on the second surface. A plurality of lower conductive pads is disposed on the first lower protection layer. A plurality of through electrodes penetrates the base layer and the first lower protection layer. The plurality of through electrodes electrically connects the metal interconnect pattern of the interconnect structure to the lower conductive pads. At least one of the insulating layer and the first lower protection layer has compressive stress. A thickness of the first lower protection layer is in a range of about 13% to about 30% of a thickness of the insulating layer.