Integrated Wafer Bonding Metrology for Post-Bond Distortion Control
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Solution Overview
Problem
Existing wafer bonding processes struggle to effectively control post-bond distortion due to inter-lot variations in wafer shape and characteristics, leading to poor bonding quality and increased production challenges.
Innovation Solution
A wafer bonding system integrated with metrology tools that measure physical parameters of wafers to generate optimized bonding recipes, using both feedforward and feedback operations to tune process conditions and achieve post-bond distortion thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed wafer bonding recipe is used for all wafers, then the process is simple and fast, but post-bond distortion varies significantly across different wafer lots
Solution Approach 1:
The system performs preliminary metrology measurements on wafers before bonding to obtain physical parameters such as curvature and thickness. These measurements are used in advance to generate customized bonding recipes that compensate for wafer-specific characteristics, thereby reducing post-bond distortion while maintaining process efficiency
Solution Approach 2:
The system dynamically adjusts bonding process parameters (temperature, pressure, time) based on measured wafer physical parameters. By changing these parameters according to each wafer's specific characteristics, the system achieves consistent post-bond distortion control across different wafer lots without requiring a completely complex customized process for each wafer
2Measurement precision
If extensive model calibration is performed to achieve accurate post-bond distortion prediction, then prediction accuracy improves, but calibration time and resources increase
Solution Approach 1:
The system performs model calibration in advance during setup phases, storing calibrated parameters for later use. This preliminary calibration action separates the time-consuming calibration process from production operations, achieving accurate distortion prediction without adding calibration time to each bonding cycle
Solution Approach 2:
The system uses measured wafer physical parameters (curvature, thickness, material properties) as inputs to a pre-calibrated model that copies the essential physics of the bonding process. This approach achieves accurate distortion prediction by using simplified model copies rather than requiring extensive real-time calibration
Data Source
AI summary
Aspects of the present disclosure provide a wafer bonding system, which, for example, can include a wafer bonding tool configured to bond a first wafer and a second wafer to each other in accordance with a first wafer bonding recipe to produce a first post-bond wafer, a metrology tool integrated with the wafer bonding tool, and a tool controller coupled to the wafer bonding tool and the metrology tool. The metrology tool can be configured to measure a physical parameter of the first wafer. The physical parameter of the first wafer representing information relates to topographical features of the first wafer. The tool controller can have a model of a wafer bonding process. The model can include an input indicative of the physical parameter of the first wafer and configured to generate the first wafer bonding recipe based, at least in part, on the physical parameter of the first wafer.