Wafer Bonding Apparatus Dynamic Push Rod Control
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Solution Overview
Problem
In wafer-to-wafer bonding processes for semiconductor manufacturing, asymmetric curvatures at adhesion points due to self-weight deformation lead to alignment errors, affecting the yield and quality of semiconductor devices.
Innovation Solution
A wafer bonding apparatus with a vacuum pump, suction stages, and adjustable push rods and suction areas, controlled by processing circuitry, to symmetrically manage wafer curvatures during bonding, minimizing alignment errors by dynamically adjusting the ratio of push rod lengths and suction areas based on bonding propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wafers are bonded using conventional vacuum suction without dynamic adjustment, then the bonding process is simple, but asymmetric curvatures occur at adhesion points due to self-weight deformation, causing alignment errors
Solution Approach 1:
The patent implements dynamic adjustment of push rod protruding lengths and suction hole activation ratios during the bonding process. The push rods can extend to different lengths at different stages, and the suction holes are activated in different ratios (e.g., 1:1, 2:1, 3:1) as bonding propagates, allowing the system to adapt to changing wafer curvature conditions and maintain alignment precision throughout the bonding process
Solution Approach 2:
The patent changes physical parameters during the bonding process, specifically the protruding lengths of push rods and the activation ratio of suction holes. By adjusting these parameters dynamically as bonding propagates from the middle region to peripheral regions, the system compensates for self-weight deformation and maintains symmetric wafer curvatures, thereby preventing alignment errors
2Productivity
If push rods apply pressure to middle regions of wafers to initiate bonding, then bonding propagation is enabled, but asymmetric curvatures develop due to self-weight, causing misalignment
Solution Approach 1:
The patent intentionally creates asymmetric conditions during different stages of bonding. Initially, push rods are extended to different lengths to create asymmetric pressure distribution that initiates bonding from the middle region. As bonding propagates, the asymmetry is adjusted by changing the extension lengths and suction hole activation ratios to maintain proper curvature symmetry, thus enabling both efficient bonding propagation and alignment precision
Solution Approach 2:
The push rods are extended to specific preliminary lengths before bonding begins, and suction holes are activated in predetermined ratios. This preliminary asymmetric configuration enables bonding to start at the middle region and propagate outward efficiently, while the pre-planned adjustment schedule ensures alignment precision is maintained throughout the process
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 alignment errors and improves the quality, performance, and reliability of semiconductor devices by ensuring symmetric wafer curvatures during bonding, enhancing the overall efficiency of the wafer-to-wafer bonding process.
Implementation Method 1
a lower stage having a first surface and including a plurality of first suction holes in the first surface, wherein the lower stage is configured to vacuum suction a first wafer on the first surface based on a vacuum pressure being supplied to the plurality of first suction holes from the vacuum pump
Data Source
AI summary
A wafer bonding apparatus includes lower and upper stages, lower and upper push rods, a position detection sensor, and processing circuitry. The stages may vacuum suction respective wafers on respective surfaces of the stages based on a vacuum pressure being supplied to respective suction holes in the respective surfaces from a vacuum pump. The push rods are movable through respective center holes in the stages to apply pressure to respective middle regions of the respective wafers. The position detection sensor may generate information indicating a bonding propagation position of the wafers based on detecting at least one wafer through a detection hole in at least one stage. The processing circuitry may process the information to detect the bonding propagation position and cause a change of at least one of a ratio of protruding lengths of the push rods, or a ratio of suction areas of the stages.