Wafer Bonding Alignment via Target Plate Intermediary
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Solution Overview
Problem
Current wafer bonding technologies face challenges in achieving precise alignment and accurate bonding between wafers, leading to potential alignment errors that can affect the yield and quality of electronic products such as CMOS image sensors and High Bandwidth Memory semiconductor packages.
Innovation Solution
A wafer bonding apparatus is designed with a first and second stage, each equipped with suction holes and image sensors to capture alignment marks and a target image sensor, allowing for precise alignment and movement to minimize alignment errors between the stages, utilizing a target plate to facilitate accurate positioning and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wafer bonding alignment methods are used, then the bonding process can be completed, but alignment errors occur between wafers reducing bonding accuracy
Solution Approach 1:
A target plate with a predetermined pattern is introduced as an intermediary element between the two wafers. This target plate serves as a reference mediator that enables precise alignment measurement between the first and second stages, thereby resolving the alignment accuracy issue without directly modifying the wafer bonding process
Solution Approach 2:
The patent replaces conventional mechanical alignment methods with an optical measurement system. Image sensors capture images of the target plate pattern, and computational algorithms calculate alignment errors, substituting direct mechanical adjustment with optical detection and computational correction to achieve higher precision
2Manufacturing precision
If alignment measurement is performed between first and second stages, then bonding accuracy improves, but the device complexity increases due to additional components
Solution Approach 1:
The target plate serves multiple functions: it acts as an alignment reference pattern for measurement, provides a standardized target for image sensor detection, and enables calculation of alignment errors between stages. This multi-functionality reduces the need for separate components for each function, thereby limiting the increase in device complexity
Solution Approach 2:
The system uses its own imaging components (image sensors) to capture and process images of the target plate for alignment measurement. The apparatus performs self-alignment verification using integrated sensors and computational algorithms, reducing the need for external alignment equipment and minimizing added complexity
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 apparatus enhances wafer bonding accuracy by enabling precise alignment and positioning between wafers, reducing alignment errors and improving the yield rate of electronic products.
Implementation Method 1
the first stage and the second stage are movable so that the target image sensor and the second mark image sensor face each other and the target plate is between the target image sensor and the second mark image sensor facing each other
Implementation Method 2
a first stage configured to suction a first wafer; a second stage configured to suction a second wafer
Data Source
AI summary
A wafer bonding apparatus including a first stage having a first surface and being configured to hold a first wafer on the first surface; a second stage having a second surface and being configured to hold a second wafer on the second surface facing the first surface; a first target image sensor on an outer portion of the first stage; a second target image sensor on an outer portion of the second stage; and a target portion on the first or second stage, the target portion having a target plate fixedly installed and spaced apart from the first or second target image sensor by a predetermined distance, wherein, in an alignment measurement of the first and second stages, the first and second stages are movable so that the first and second target image sensors face each other and the target plate is between the first and second target image sensors.