Alignment Key Structure in Semiconductor Devices
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Solution Overview
Problem
The existing wire bonding process in semiconductor device manufacturing often results in etch damage to metal wirings during the formation of alignment keys, leading to signal noise and reliability issues due to the exposure of signal lines and potential short circuits.
Innovation Solution
The alignment key structure includes a passivation layer with a first opening that exposes a metal wiring, with a width narrower than the wiring itself, preventing etching damage by minimizing the area affected by the etchant and ensuring the first metal wirings are separated from the opening, thus protecting them from plasma etch damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the first opening is formed to expose the metal wiring for alignment key, then the wire bonding process can be performed, but etch damage occurs to the metal wirings
Solution Approach 1:
The passivation layer is selectively removed only in the specific region where alignment key exposure is needed, while maintaining the passivation layer in other regions to protect metal wirings. This localized removal allows the etchant to affect only the necessary area, preventing etch damage to surrounding metal wirings while still enabling the wire bonding alignment process.
2Manufacturing precision
If the etching process is performed to form the first opening, then the alignment key is created, but signal noise occurs due to etch damage to signal lines
Solution Approach 1:
The passivation layer is removed only in the specific location needed for alignment key exposure, creating a localized etching zone. This prevents the etchant from contacting signal lines in other areas, thereby eliminating the source of signal noise while still achieving the required alignment key formation precision.
Solution Approach 2:
The passivation layer acts as an intermediary protective barrier between the etchant and the metal wirings. By selectively removing this intermediary layer only where needed, the etchant is directed to affect only the necessary regions, preventing harmful interactions with signal lines that would generate noise.
3Measurement precision
If the first opening is formed with sufficient width to expose the metal wiring, then the alignment key is visible, but the area affected by etchant increases causing more damage
Solution Approach 1:
The passivation layer removal is confined to the minimum necessary area to provide adequate alignment key visibility. This localized approach ensures that the alignment key remains clearly visible for wire bonding while minimizing the exposure area to the etchant, thereby reducing the overall damage area to metal wirings.
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 solution effectively reduces etching damage to both second and first metal wirings, enhancing the reliability and productivity of semiconductor devices by minimizing signal noise and preventing alignment errors during the wire bonding process.
Implementation Method 1
the first opening 132 and the second opening 134 are formed by an etching process using an etchant such as plasma
Data Source
AI summary
An alignment key structure in a semiconductor device is provided. The alignment key structure includes an insulation layer formed on a substrate, and a passivation layer pattern formed on the insulation layer. The insulation layer includes a plurality of metal wirings. The passivation layer pattern includes a first opening that exposes at least one of the metal wirings. Moreover, the first opening has a width which is narrower than a width of the exposed metal wiring.