Wafer Bonding Alignment Using Thermal Expansion Correction
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Solution Overview
Problem
Existing wafer bonding technologies face challenges in achieving accurate alignment, particularly in compensating for non-linear offset errors, which can lead to reduced wafer yield and compromised circuit functionality.
Innovation Solution
A wafer bonding device and method that includes a first and second fixing apparatus, a reflection member, a mark reader, and a heating apparatus. The device thermally expands the wafers to align alignment marks at the center of the mark reader's field of view, thereby compensating for non-linear errors and improving alignment accuracy.
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 non-linear offset errors occur leading to poor alignment accuracy
Solution Approach 1:
The patent changes the physical state of the wafer from cold to hot, utilizing thermal expansion to shift the alignment mark position. By heating the wafer to a predetermined temperature, the alignment mark moves to a corrected position that compensates for non-linear offset errors, thereby improving alignment accuracy without requiring complex measurement systems.
Solution Approach 2:
The patent performs preliminary heating of the wafer before the actual bonding alignment process. By pre-heating the wafer to expand it and position the alignment mark at the correct location in advance, the system eliminates non-linear offset errors before measurement and bonding occur, ensuring high alignment accuracy from the start.
2Productivity
If alignment accuracy is not improved, then the bonding process is simple, but wafer yield and circuit functionality are reduced
Solution Approach 1:
The patent utilizes temperature as a controllable parameter to achieve alignment correction. By simply adjusting the temperature of the wafer using a heating element, the system corrects non-linear offset errors and improves alignment accuracy, leading to higher wafer yield without adding complex mechanical or optical alignment devices.
Solution Approach 2:
The patent replaces complex mechanical alignment systems with a thermal expansion-based alignment method. Instead of using precision mechanical stages or complex optical alignment systems, the invention uses controlled heating to expand the wafer and automatically position the alignment mark, simplifying the device structure while improving productivity.
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 solution effectively compensates for non-linear errors in wafer alignment, enhancing the accuracy and stability of the wafer bonding process, which in turn improves wafer yield and circuit functionality.
Implementation Method 1
The heating apparatus is configured to heat the first wafer to thermally expand the first wafer so that the first alignment mark is located at a central position of a field of view of the mark reader
Implementation Method 2
The mark reader reads position information about the first alignment mark and the second alignment mark by means of the reflection member
Data Source
AI summary
A wafer bonding device includes: a first fixing apparatus fixing a first wafer, on which a first alignment mark is disposed; a second fixing apparatus fixing a second wafer, on which a second alignment mark is disposed, the second fixing apparatus being disposed opposite to the first fixing apparatus; a reflection member between the first and second fixing apparatuses; a mark reader which reads position information about the first and second alignment marks by means of the reflection member, for aligning the first wafer with the second wafer; and a heating apparatus, configured to heat the first wafer or the second wafer to thermally expand the first wafer or the second wafer so that the first alignment mark or the second alignment mark is located at a central position of a field of view of the mark reader. A wafer bonding method also is involved.