Hybrid Bonding Pad Alignment via Lithographic Magnification Compensation
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Solution Overview
Problem
Creating reliable electrical connections between finely pitched contact pads in directly bonded semiconductor elements is challenging due to misalignment caused by differential expansion and warpage resulting from thickness differences and residual stresses in the bonding layer.
Innovation Solution
Applying a lithographic magnification correction factor to compensate for differential expansion by adjusting the patterning of contact pads on one or both semiconductor elements, combined with a differential expansion compensation structure to reduce warpage, ensuring proper alignment and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If directly bonded structures with finely pitched contact pads are used, then device integration density is improved, but alignment precision between opposing contact pads deteriorates due to differential expansion and warpage
Solution Approach 1:
The patent applies preliminary action by performing lithographic magnification correction during the patterning process before bonding. A correction factor is applied to the contact pad patterns on one or both elements to pre-compensate for the differential expansion that will occur during bonding, ensuring alignment precision is maintained even with finely pitched contact pads
2Stability of the object's composition
If thickness difference between bonded elements is reduced, then warpage is improved, but manufacturing complexity increases due to additional thinning processes
Solution Approach 1:
The patent applies parameter changes by systematically varying the lithographic magnification correction factor based on the thickness parameters of the bonded elements. The correction factor is determined as a function of the thickness difference between elements, allowing the process to accommodate different thickness combinations without requiring physical modification of the elements themselves
3Quantity of substance
If contact pad size is reduced for fine pitch, then integration density is improved, but alignment tolerance margin deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-compensating for alignment issues through lithographic magnification correction. The correction factor is calculated and applied during patterning to ensure that even with reduced contact pad sizes for fine pitch applications, the alignment tolerance margin is maintained by accounting for differential expansion before bonding occurs
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 aligns contact pads across the bonded structure, ensuring reliable electrical connections even with fine pitches and small pad sizes, thereby improving device yield and performance.
Implementation Method 1
obtaining a lithographic magnification correction factor to compensate for differential expansion between the first and second semiconductor elements
Implementation Method 2
a differential expansion compensation structure to reduce warpage
Data Source
AI summary
A method of direct hybrid bonding first and second semiconductor elements of differential thickness is disclosed. The method can include patterning a plurality of first contact features on the first semiconductor element. The method can include second a plurality of second contact features on the second semiconductor element corresponding to the first contact features for direct hybrid bonding. The method can include applying a lithographic magnification correction factor to one of the first patterning and second patterning without applying the lithographic magnification correction factor to the other of the first patterning and the second patterning. In various embodiments, a differential expansion compensation structure can be disposed on at least one of the first and the second semiconductor elements. The differential expansion compensation structure can be configured to compensate for differential expansion between the first and second semiconductor elements to reduce misalignment between at least the second and fourth contact features.