Wafer Bonding Chuck Pressure Control to Reduce Substrate Distortion
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Solution Overview
Problem
Conventional methods for bonding semiconductor wafers using hydrophilized surfaces can lead to distortion due to local deformations, resulting in reduced yield of elements formed in the combined substrate.
Innovation Solution
A bonding apparatus with a lower chuck having an attraction surface and an underlying space with controlled pressure lower than atmospheric pressure, which reduces distortion by evenly distributing pressure across the non-bonding surface of the wafer, and lift pins to space the substrate from the chuck, allowing for precise bonding without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding methods using hydrophilized surfaces are used, then substrates can be bonded together, but local deformations occur causing distortion in the combined substrate
Solution Approach 1:
The patent changes the pressure parameter in the space beneath the substrate from atmospheric pressure to a controlled negative pressure (lower than atmospheric pressure). This parameter change prevents local deformations during bonding by creating uniform pressure distribution across the substrate surface, thereby reducing distortion while maintaining bonding quality through van der Waals forces and hydrogen bonds
Solution Approach 2:
The patent introduces a controlled pressure environment (negative pressure space) as an intermediary between the substrate and the external atmosphere. This intermediary space, maintained at pressure lower than atmospheric pressure, acts as a mediator that prevents atmospheric pressure from causing local deformations on the substrate surface during the bonding process
2Strength
If pressure is applied to bond substrates, then bonding strength increases, but non-uniform pressure distribution causes local deformations
Solution Approach 1:
The patent changes the pressure parameter from positive or atmospheric pressure to controlled negative pressure in the space beneath the substrate. This parameter change achieves uniform pressure distribution across the entire substrate surface, preventing local deformations while still enabling strong bonding through the controlled pressure environment that enhances van der Waals forces and hydrogen bonding
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 reduces distortion in the combined substrate, enhancing the yield and quality of bonded semiconductor wafers by ensuring uniform pressure distribution and controlled bonding processes.
Implementation Method 1
The attracting pressure generator is configured to generate an attracting pressure in the attraction surface
Implementation Method 2
the space is controlled to have a pressure lower than an atmospheric pressure
Implementation Method 3
the modified surfaces of the substrates are hydrophilized, and the hydrophilized substrates are bonded to each other by a van der Waals force and a hydrogen bond
Implementation Method 4
the hydrophilized substrates are bonded to each other by a van der Waals force and a hydrogen bond
Data Source
AI summary
A bonding apparatus includes a first holder, a second holder, an attracting pressure generator and a lift pin. The first holder is configured to hold a first substrate. The second holder, disposed at a position facing the first holder, has an attraction surface configured to attract a second substrate to be bonded to the first substrate. The attracting pressure generator is configured to generate an attracting pressure in the attraction surface. The lift pin is configured to space the second substrate on the attraction surface apart from the second holder. The second holder is provided with a space including an opening through which the lift pin passes, and the space is controlled to have a pressure lower than an atmospheric pressure.