Hybrid Wafer Bonding Tool With Stressor Film Shape Correction
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Solution Overview
Problem
Current semiconductor fabrication processes face challenges in accurately bonding wafers due to non-linear physical wafer distortions induced by processing, leading to alignment failures and significant yield loss, especially in advanced packaging processes.
Innovation Solution
A hybrid system with modules for wafer shape correction and bonding, including metrology, stressor film deposition and modification, alignment, and bonding, to manipulate wafer shape and enhance bonding yield by using stress control layers and heat/radiation patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional alignment systems are used for wafer bonding, then the bonding process is simple, but alignment accuracy deteriorates due to non-linear wafer distortions
Solution Approach 1:
The system performs preliminary wafer shape measurement and distortion mapping before bonding occurs. By measuring wafer geometry upfront and pre-calculating compensation transformations, the system prepares correction data in advance that is applied during alignment, thereby achieving high precision without adding complex real-time correction mechanisms during bonding.
Solution Approach 2:
The system implements feedback by measuring actual wafer shapes using metrology modules, comparing them against ideal geometries, and using the measured distortion data to calculate and apply compensatory transformations during alignment. This closed-loop feedback mechanism enables the system to adapt to actual wafer variations and achieve accurate alignment despite non-linear distortions.
2Manufacturing precision
If wafer shape correction modules are added to the bonding system, then alignment accuracy improves, but device complexity increases
Solution Approach 1:
The system achieves multi-functionality by integrating wafer shape measurement, distortion analysis, and alignment compensation capabilities within the bonding system. Rather than adding separate dedicated correction equipment, the system combines these functions into unified modules that serve both measurement and alignment purposes, thereby improving precision while limiting the increase in overall device complexity.
3Manufacturing precision
If non-linear wafer distortions are present, then handling is easier, but alignment accuracy deteriorates
Solution Approach 1:
The system applies preliminary anti-action by measuring wafer distortions before bonding and pre-calculating inverse transformation matrices that compensate for the expected non-linear effects. By applying these pre-computed corrections in advance during the alignment stage, the system counteracts the distorting effects before they impact bonding accuracy, thereby maintaining overlay precision despite wafer shape variations.
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 system reduces bonding overlay residuals, improves bond strength, and increases yield by correcting wafer distortions, enabling handling of highly distorted wafers and addressing deficiencies in traditional alignment systems.
Implementation Method 1
a stressor film deposition module configured to form a first stressor film on the first wafer
Implementation Method 2
The stressor film modification module includes a direct-write exposure apparatus configured to expose the first stressor film to a pattern of electromagnetic radiation based on the first modification map
Implementation Method 3
The stressor film modification module includes a development apparatus configured to develop a photoresist layer of the first stressor film to form a relief pattern
Implementation Method 4
The heat array includes an array of resistors. Each resistor is configured to generate a respective amount of heat based on a respective current flowing through
Implementation Method 5
Each resistor is configured to generate a respective amount of heat based on a respective current flowing through
Implementation Method 6
The stressor film modification module includes a laser system configured to heat at least one of the first wafer or a wafer chuck that is configured to hold the first wafer
Implementation Method 7
a bonding module configured to bond the first wafer to the second wafer
Data Source
AI summary
A device includes a first set of modules configured for wafer shape correction and a second set of modules configured for wafer bonding. The first set of modules includes a metrology module configured to measure wafer shape data of a first wafer and a second wafer, including relative z-height values of the first wafer and the second wafer. A stressor film deposition module is configured to form a first stressor film on the first wafer. A stressor film modification module is configured to modify the first stressor film based on a first modification map that defines adjustments to internal stresses of the first wafer and is generated based on the wafer shape data. The second set of modules includes an alignment module configured to align the first wafer with the second wafer, and a bonding module configured to bond the first wafer to the second wafer.