Monitoring Opening for Semiconductor Substrate Inspection
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Solution Overview
Problem
In the manufacturing of BGA type semiconductor devices, the shape and size of openings formed in the semiconductor substrate cannot be visually inspected until the wafer is cut, making it difficult to determine if the substrate is completely removed or if over-etching has occurred, and the aperture measurement is not possible without cross-sectional observation.
Innovation Solution
A monitoring opening is formed in the semiconductor substrate, allowing for clear visualization and measurement of the opening's aperture through a patterned metal layer or monitoring pattern, enabling inspection without cutting the wafer and providing assurance of proper opening formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the wafer is cut to inspect the opening formation, then the shape and size of openings can be observed, but the inspection process becomes complex and time-consuming requiring cross-sectional observation
Solution Approach 1:
A monitoring opening is formed in advance during the opening formation process, allowing for real-time visual inspection of the opening shape, size, and etching depth without requiring subsequent wafer cutting or cross-sectional observation. This preliminary monitoring structure enables direct observation of the opening formation result.
Solution Approach 2:
The monitoring opening serves as a simplified copy or representative sample of the actual openings, allowing inspection of opening formation quality through a single accessible opening rather than requiring examination of multiple cut sections. The monitoring opening replicates the etching characteristics and can be observed directly from one side.
2Ease of manufacture
If the opening formation is inspected without cutting the wafer, then the inspection process is simplified, but the ability to measure aperture and determine complete substrate removal is lost
Solution Approach 1:
The monitoring opening is formed simultaneously with the other openings during the same etching process, allowing for real-time measurement of opening aperture and verification of complete substrate removal without requiring subsequent wafer cutting. The monitoring opening provides direct visual access to assess etching completeness and dimensional accuracy.
3Reliability
If multiple openings are formed for monitoring purposes, then the inspection capability is improved, but the device structure becomes more complex
Solution Approach 1:
The monitoring function is separated from the functional openings by creating a distinct monitoring opening in the scribe line area, while the functional openings remain in the active device regions. This segmentation allows the monitoring opening to serve its inspection purpose without interfering with the electrical or optical functions of the device openings.
Solution Approach 2:
The monitoring opening is placed in a specific location (scribe line) where it serves the monitoring function, while other openings in different locations maintain their functional qualities for electrical connection or optical purposes. Each opening has its specific quality optimized for its intended purpose.
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
Enables real-time inspection and measurement of opening formation, ensuring complete removal and accurate aperture sizing, thus improving the manufacturing process by preventing over-etching and ensuring correct device assembly.
Implementation Method 1
A monitoring opening is formed in the semiconductor substrate, allowing for clear visualization and measurement of the opening's aperture
Data Source
AI summary
A result of formation of an opening in a semiconductor substrate can be judged without cutting a semiconductor wafer and observing a cross-section of the cut wafer. A semiconductor device of this invention includes a semiconductor substrate, a pad electrode formed on the semiconductor substrate, an opening formed in the semiconductor substrate to expose the pad electrode, a wiring layer connected with the pad electrode through the opening and a monitoring opening formed in a scribe line to monitor a result of the formation of the opening.