Copper Alignment Mark Protection in Semiconductor Passivation
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Solution Overview
Problem
In semiconductor device manufacturing, the exposure of copper alignment marks in the scribe lane during passivation film removal leads to potential contamination of equipment and process environment, causing defects and reducing yield.
Innovation Solution
A method involving sequential deposition of passivation films with differing etching selectivities, where a first passivation film protects the copper alignment mark, and a second and third passivation film are selectively removed in the scribe lane to prevent exposure, using a damascene process and photolithographic techniques to ensure the alignment mark remains covered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the passivation film in the scribe lane is removed to prevent stress defects, then the reliability of the device is improved, but the copper alignment mark becomes exposed causing contamination of equipment and process environment
Solution Approach 1:
The passivation film structure is segmented into multiple layers with different etching selectivities. The first passivation film has high etching selectivity relative to the second passivation film, allowing selective removal of the second film in the scribe lane while the first film remains to protect the copper alignment mark. This segmentation enables different regions of the device to have different passivation configurations tailored to their specific needs.
Solution Approach 2:
The patent applies local quality by providing different passivation film configurations in different regions. In the chip area, both first and second passivation films are present for comprehensive protection. In the scribe lane, only the first passivation film is retained after selective removal of the second film, providing sufficient protection for the copper alignment mark while preventing stress defects during dicing.
2Ease of manufacture
If a single passivation film is used for the entire substrate, then the manufacturing process is simplified, but stress during scribing causes defects in the passivation film
Solution Approach 1:
The passivation film is segmented into multiple layers deposited at different stages. The first passivation film is deposited early to provide initial protection, while the second passivation film is deposited later and selectively removed in the scribe lane. This segmented approach maintains manufacturing precision by ensuring proper stress management during scribing while keeping the process relatively simple through sequential deposition steps.
3Manufacturing precision
If the second passivation film is selectively removed in the scribe lane, then stress-induced defects are prevented, but the copper alignment mark may become exposed causing contamination
Solution Approach 1:
The first passivation film serves as a pre-established protective layer that cushions and protects the copper alignment mark before the second passivation film is selectively removed. This prior cushioning ensures that even after removal of the second film, the copper remains protected from exposure and contamination, while still allowing stress relief in the scribe lane.
Solution Approach 2:
The first passivation film acts as an intermediary protective layer between the copper alignment mark and the external environment. When the second passivation film is selectively removed in the scribe lane, the first film remains as an intermediate barrier that prevents direct exposure of the copper, thus preventing contamination while allowing the stress relief function.
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
Prevents contamination and defects by maintaining the copper alignment mark under protection, enhancing manufacturing yield and process integrity.
Implementation Method 1
a first passivation film which protects the alignment mark; and a second passivation film which is selectively removed in the scribe lane
Implementation Method 2
patterned by a predetermined photolithography process
Data Source
AI summary
A semiconductor device and a method manufacturing the same prevents copper from being exposed to a surface of a passivation film after a copper metal line formation, to avoid contamination of processing equipment and the process environment. The method includes providing a substrate with a scribe lane and a chip area in which metal wiring layers are formed, forming a dielectric film, forming a conductive film on the dielectric film in a chip area and an alignment mark on the dielectric film in a scribe lane, forming passivation films, exposing the conductive film by removing the passivation films in a bonding pad portion in a chip area, forming another conductive film in the bonding pad portion to electrically connect with the conductive film, forming another passivation film, and selectively removing the passivation films.