Planarized Passivation Layer for Semiconductor Heat Dissipation
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Solution Overview
Problem
The miniaturization and standardization of semiconductor packages, along with increased operating speeds, lead to reliability issues in semiconductor chips due to challenges in heat dissipation and electrical connectivity.
Innovation Solution
A semiconductor device with a semiconductor substrate having metal lines, a first passivation layer with a non-planar surface, and a second passivation layer with a planar surface, where heat dissipating micro-bumps are disposed on the planar surface of the second passivation layer to enhance thermal management and electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the passivation layer is formed to cover metal lines with a non-planar top surface, then the electrical connectivity and heat dissipation are improved, but the manufacturing precision and reliability deteriorate due to abnormal micro-bump formation
Solution Approach 1:
The passivation layer is divided into two separate layers: a first passivation layer that covers the metal lines and follows their non-planar profile, and a second passivation layer that is planarized to provide a uniform surface for micro-bump formation. This segmentation allows each layer to fulfill its specific function without compromise.
Solution Approach 2:
The solution transitions from a single-layer passivation structure to a multi-layer vertical structure. The first layer operates at the interface level with metal lines, while the second layer operates at the top surface level for bump formation, effectively separating the electrical connectivity function from the mechanical bonding function in different dimensional zones.
2Speed
If the operating speed of semiconductor packages is increased, then the bandwidth is improved, but the heat dissipation capability deteriorates leading to reliability issues
Solution Approach 1:
The first passivation layer acts as an intermediary structure that provides thermal pathways between the metal lines and the heat dissipation structures. Its non-planar profile allows direct thermal contact with metal lines while the second planarized layer provides a stable platform for heat-dissipating micro-bumps, effectively mediating between high-speed operation and thermal management.
3Area of moving object
If the semiconductor package is miniaturized and standardized, then the integration density is improved, but the heat dissipation and electrical connectivity deteriorate
Solution Approach 1:
The passivation structure exhibits local quality variations: the first passivation layer has a non-planar topology locally adapted to match the underlying metal line arrangement for optimal electrical and thermal contact, while the second layer has a planar topology locally optimized for uniform micro-bump formation. This local adaptation allows miniaturization without sacrificing heat dissipation efficiency.
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 solution effectively addresses heat dissipation and electrical connectivity issues, improving the operational reliability and bandwidth of semiconductor packages by ensuring efficient heat radiation and preventing abnormal micro-bump formation through planarization of the passivation layers.
Implementation Method 1
chemically mechanically polishing the second passivation layer to planarize a top surface of the second passivation layer
Data Source
AI summary
A semiconductor device includes a semiconductor substrate divided into a pad region and a cell region and having an active surface and an inactive surface opposite to the active surface, a plurality of metal lines on the active surface of the semiconductor substrate, passivation layers on the active surface of the semiconductor substrate, and a plurality of bumps in the cell region. The passivation layers include a first passivation layer covering the plurality of metal lines and having a non-planarized top surface along an arrangement profile of the plurality of metal lines, and a second passivation layer on the non-planarized top surface of the first passivation layer and having a planarized top surface on which the plurality of bumps are disposed.