Wafer Bonding Vacuum Control for Surface Profile Uniformity
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Solution Overview
Problem
Existing wafer bonding technologies face challenges in minimizing surface profile distortion during the bonding process, leading to local distortion in the bonded pair of wafers.
Innovation Solution
A wafer bonding system that utilizes optical surface profilers, such as laser displacement sensors or interferometers, to measure and compensate for surface profile distortions by adjusting vacuum pressures on the chuck, ensuring more even surface profiles before bonding, thereby reducing distortion during the bonding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wafer bonding methods are used, then bonding can be achieved, but surface profile distortion occurs leading to local distortion in bonded wafers
Solution Approach 1:
The patent applies preliminary action by measuring and compensating for surface profile distortion before the bonding process occurs. The system measures the surface profile of wafers prior to bonding and adjusts vacuum pressures in advance to flatten distorted regions, ensuring uniform surfaces are presented to each other before contact. This prevents distortion from propagating into the final bonded structure.
Solution Approach 2:
The patent implements feedback by continuously monitoring surface profile measurements and using this information to dynamically adjust vacuum pressure distribution. The system measures surface distortion, processes this data to determine required compensation, and modifies vacuum pressures in specific zones accordingly. This closed-loop control ensures surface uniformity is maintained throughout the bonding process.
2Manufacturing precision
If vacuum pressure is increased to improve bonding uniformity, then surface profile distortion is reduced, but wafer deformation may occur
Solution Approach 1:
The patent applies local quality by distributing vacuum pressure non-uniformly across different zones of the wafer holder. Instead of applying uniform vacuum pressure that could cause overall wafer deformation, the system identifies specific distorted regions through measurement and applies localized vacuum pressure adjustments only to those areas. This targeted approach corrects surface profile distortion while minimizing stress on the overall wafer structure.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting vacuum pressure levels based on measured surface profile characteristics. The system varies vacuum pressure parameters in response to detected distortion patterns, increasing pressure in regions requiring flattening while maintaining lower pressures in already-uniform regions. This adaptive parameter adjustment achieves bonding uniformity without excessive overall pressure that could damage wafers.
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 effectively decreases local distortion of bonded wafer pairs by compensating for surface profile distortions, resulting in improved bonding uniformity and accuracy.
Implementation Method 1
A first surface profiler (e.g., an interferometer) measures a surface profile distortion of the first wafer
Implementation Method 2
A first surface profiler (e.g., an interferometer) measures a surface profile distortion of the first wafer
Implementation Method 3
vacuum pressures of a plurality of vacuum zones on the chuck are adjusted
Implementation Method 4
vacuum pressures of vacuum zones on the chuck are adjusted to compensate for the surface profile distortion
Implementation Method 5
In fusion bonding, an oxide surface of a wafer is bonded to an oxide surface or a silicon surface of another wafer
Implementation Method 6
In direct metal-to-metal bonding, two metal pads are pressed against each other at an elevated temperature, and the inter-diffusion of the metal pads causes the bonding of the metal pads
Data Source
AI summary
A method of forming a semiconductor device includes mounting a first wafer on a first wafer chuck and mounting a second wafer on a second wafer chuck. A push pin is extended through the first wafer chuck to distort the first wafer. A surface profile distortion of the first wafer is measured with a first surface profiler. A vacuum pressure of a vacuum zone on the first wafer chuck is adjusted using a measurement of the surface profile distortion. The first wafer chuck is moved towards the second wafer chuck so that the first wafer physically contacts the second wafer, and the first wafer is bonded to the second wafer.