Wafer Molecular Adhesion Bonding Alignment Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Molecular adhesion bonding at low pressure results in inhomogeneous deformations and misalignment of microcomponents in multilayer semiconductor structures due to premature initiation of the bonding wave during alignment and contact, leading to defects and reduced quality in three-dimensional integration.
Innovation Solution
A method involving initial alignment and contact of wafers in an environment at a pressure greater than a threshold, followed by a reduction to a lower pressure to spontaneously initiate the bonding wave, using mechanical pressure control to limit deformations, and employing spacer elements and a pusher to maintain precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If molecular adhesion bonding is carried out at low pressure (≤1 millibar), then bonding energy is high and bonding wave propagation is rapid, but inhomogeneous deformations and misalignment occur due to premature bonding wave initiation during alignment and contact
Solution Approach 1:
The patent applies preliminary action by performing the alignment and contact operations at ambient pressure before reducing to low pressure for bonding. This preliminary alignment at higher pressure prevents premature bonding wave initiation, ensuring that the wafer surfaces are properly positioned before the bonding process begins. The alignment is completed while the environment is still at higher pressure, then the pressure is reduced to initiate controlled bonding.
Solution Approach 2:
The patent employs dynamics by dynamically changing the pressure environment during the bonding process. The pressure is first maintained at ambient levels during alignment and contact, then reduced to low pressure to initiate and control the bonding wave propagation. This dynamic pressure adjustment allows the process to exploit the benefits of both high pressure (stable alignment) and low pressure (high bonding energy).
2Productivity
If the bonding wave is initiated during alignment and contact operations at low pressure, then bonding occurs rapidly, but irreversible inhomogeneous deformations occur on the wafers
Solution Approach 1:
The patent applies preliminary action by completing all alignment and contact operations at ambient pressure before reducing to low pressure. This ensures that the wafer surfaces are properly positioned and in contact before the bonding wave is initiated. Only after alignment is complete does the pressure reduction occur, preventing premature bonding during alignment operations.
Solution Approach 2:
The patent applies beforehand cushioning by maintaining ambient pressure during the alignment and contact phases, which acts as a cushioning environment that prevents premature bonding wave initiation. This higher pressure environment cushions against the risk of accidental bonding during handling, allowing stable alignment before the controlled low-pressure bonding phase begins.
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
This approach significantly reduces residual alignment offsets between microcomponents to less than 100 nm, minimizing manufacturing defects such as short circuits and ensuring proper coloration function in pixel-based imagers, while maintaining the advantages of low-pressure bonding.
Implementation Method 1
molecular adhesion bonding at low pressure between two wafers
Data Source
AI summary
A method for bonding first and second wafers by molecular adhesion. The method includes placing the wafers in an environment having a first pressure (P1) greater than a predetermined threshold pressure above which initiation of bonding wave propagation is prevented, bringing the first wafer and the second wafer into alignment and contact, and spontaneously initiating the propagation of a bonding wave between the wafers after they are in contact solely by reducing the pressure within the environment to a second pressure (P2) below the threshold pressure.