HEMT Stepped Sidewall Passivation for Dicing Stress Relief
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Solution Overview
Problem
Current high electron mobility transistor (HEMT) semiconductor devices face challenges in yield rate during manufacturing, particularly due to stress accumulation and deformation issues during the dicing process, leading to peeling and damage.
Innovation Solution
A semiconductor device configuration featuring a stepped sidewall structure with a conformal passivation layer that extends from the central area to the peripheral area, adapting to the stepped profile and reducing stress concentrations, thereby improving uniformity and preventing peeling during dicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional flat passivation layer is used, then the manufacturing process is simple, but stress accumulates and causes peeling during dicing
Solution Approach 1:
The sidewall is divided into multiple stepped levels rather than being a single continuous structure. The passivation layer is segmented to conform to each step, creating discrete stress management zones that prevent cumulative stress buildup during dicing operations.
Solution Approach 2:
The passivation layer is given different local properties by conforming it to the stepped sidewall profile. Each step creates a localized region with specific stress distribution characteristics, allowing the structure to better accommodate thermal and mechanical stresses in different areas.
2Reliability
If the passivation layer is made conformal to the stepped sidewall, then stress is distributed evenly, but the manufacturing process becomes more complex
Solution Approach 1:
The stepped sidewall structure is formed before applying the passivation layer. This preliminary structuring creates a pre-defined template that guides the conformal deposition process, ensuring uniform thickness and stress distribution without requiring complex real-time adjustments during passivation layer formation.
Solution Approach 2:
The stepped sidewall acts as an intermediary structure between the underlying semiconductor layers and the passivation layer. It mediates the stress transfer by providing a gradual transition profile that distributes mechanical and thermal stresses evenly across the passivation layer during subsequent processing and dicing operations.
3Ease of manufacture
If a simple sidewall structure is used, then manufacturing is easier, but stress concentration causes deformation and peeling
Solution Approach 1:
The sidewall structure transitions from a two-dimensional vertical profile to a three-dimensional stepped configuration. This dimensional change introduces horizontal surfaces that act as stress relief zones, breaking the continuous vertical stress path and preventing concentration at any single location during dicing.
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 stepped sidewall configuration enhances the yield rate of semiconductor device manufacturing by distributing stress evenly and maintaining uniformity of the passivation layer, preventing deformation and peeling, thus improving the reliability and efficiency of the manufacturing process.
Implementation Method 1
The stepped sidewall configuration enhances the yield rate of semiconductor device manufacturing by distributing stress evenly
Implementation Method 2
A semiconductor device configuration featuring a stepped sidewall structure with a conformal passivation layer that extends from the central area to the peripheral area, adapting to the stepped profile
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, first and second nitride-based semiconductor layers, S/D electrodes, a gate electrode, and a first passivation layer. The first nitride-based semiconductor layer is disposed over the semiconductor substrate. The second nitride-based semiconductor layer is disposed on the first nitride-based semiconductor layer and has a bandgap greater than a bandgap of the first nitride-based semiconductor layer, so as to form a 2DEG region. The S/D electrodes is disposed over the second nitride-based semiconductor layer. The gate electrode is disposed between the S/D electrodes. The first passivation layer is disposed over the second nitride-based semiconductor layer. Edges of the first and second nitride-based semiconductor layers and the first passivation layer collectively form a stepped sidewall over the semiconductor substrate. The stepped sidewall includes at least one laterally-extending portions with at least two riser portion connecting the at least one laterally-extending portion.