Wafer Bonding Alignment Using Transmissive Optical Beams
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Solution Overview
Problem
The existing wafer bonding technology in 3D NAND Flash manufacturing faces alignment errors due to interference from optical signals, leading to bonding failures.
Innovation Solution
A wafer bonding method using a transmissive optical beam to determine and adjust the relative position of alignment marks on two wafers, allowing for precise alignment and bonding by reducing interference and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical signals are used for alignment during wafer bonding, then alignment can be performed, but position errors occur due to interference properties of the optical signal
Solution Approach 1:
The patent extracts the harmful interference property from the optical signal by using a transmissive optical beam that passes through the wafer rather than reflecting off the surface. This transmission-based approach eliminates the interference that causes position errors while maintaining the alignment function.
Solution Approach 2:
The patent introduces a transmissive optical beam as an intermediary that passes through the wafer material itself to detect alignment marks. This intermediary approach allows alignment detection without the harmful surface reflection interference that plagues traditional optical alignment methods.
2Ease of operation
If traditional optical alignment methods are used, then alignment process can be completed, but bonding failure occurs due to position errors
Solution Approach 1:
The patent replaces the traditional reflective optical alignment system with a transmissive optical system. This substitution fundamentally changes how alignment is detected by using light transmission through the wafer rather than light reflection from the surface, thereby eliminating interference-induced position errors.
Solution Approach 2:
The patent changes the optical parameter from reflection-based detection to transmission-based detection. By altering how the optical beam interacts with the wafer (from surface reflection to bulk transmission), the system achieves both ease of operation and high manufacturing precision.
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 method reduces position errors and enhances the reliability and accuracy of wafer bonding, improving the success rate and quality of 3D NAND Flash manufacturing.
Implementation Method 1
the transmissive optical beam has a property of transmitting through a wafer
Data Source
AI summary
An apparatus for wafer bonding includes a first bearing table configured to hold a first wafer provided with at least one first alignment mark; a second bearing table, opposite to the first bearing table, and configured to hold a second wafer provided with at least one second alignment mark; an alignment component, located on at least a side of the first or second bearing table, and configured to determine first and second position parameters of the first and second alignment marks, respectively, by using an optical beam; a mobile component, connected to the first and second bearing tables, and configured to adjust, according to the first an second position parameters, a relative position between the first and second wafers until a relative position between the first and second alignment marks satisfies a predetermined bonding condition; and a bonding component, connected to the first and second bearing tables, and configured to bond the first wafer to the second wafer.