Backside Pad Structures Without Through-Silicon Contacts
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Solution Overview
Problem
Existing semiconductor devices face challenges in efficiently forming pad structures without the need for through silicon contacts, which complicates the fabrication process and may introduce stress.
Innovation Solution
The formation of pad structures on the back side of a semiconductor die, utilizing highly doped semiconductor materials like polysilicon to facilitate electrical coupling with contact structures, and using isolation structures to separate and isolate these pad structures, thereby simplifying the fabrication process and reducing stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through silicon contacts are used to form pad structures, then electrical connection is achieved, but fabrication complexity increases and stress is introduced
Solution Approach 1:
The patent extracts the through silicon contact structure from the conventional design and replaces it with a back-side pad structure that connects to contact structures without penetrating through the silicon substrate. This eliminates the complex fabrication steps required for through silicon contacts while maintaining electrical connection functionality.
Solution Approach 2:
Instead of forming pad structures from the front side through through silicon contacts, the patent inverts the approach by forming pad structures on the back side of the semiconductor die. This inversion simplifies the fabrication process and reduces stress by avoiding the need to penetrate through the entire silicon thickness.
2Ease of manufacture
If through silicon contacts are used, then pad structures are formed, but stress is introduced in the semiconductor device
Solution Approach 1:
The patent removes the stress-inducing through silicon contact structure and replaces it with a back-side pad configuration. The pad structures on the back side connect to contact structures without requiring deep penetration through the silicon, thereby eliminating the mechanical stress that would otherwise be introduced by through silicon contacts.
3Reliability
If isolation structures are added to separate pad structures, then electrical isolation is improved, but device complexity increases
Solution Approach 1:
The patent combines the isolation function with the existing back-side pad structure formation process. The isolation structures are integrated into the same fabrication sequence as the pad structures, using the same dielectric material deposition and patterning steps. This merging approach provides electrical isolation without significantly increasing overall device complexity.
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 allows for efficient formation of pad structures without through silicon contacts, enhancing conductivity and reducing stress in the semiconductor device while optimizing the fabrication process for both vertical memory cell strings and periphery circuitry.
Implementation Method 1
utilizing highly doped semiconductor materials like polysilicon to facilitate electrical coupling with contact structures
Data Source
AI summary
Aspects of the disclosure provide a semiconductor device and a method to fabricate the semiconductor device. The semiconductor device includes a first die comprising a first contact structure formed on a face side of the first die. The semiconductor device includes a first semiconductor structure and a first pad structure that are disposed on a back side of the first die. The first semiconductor structure is conductively connected with the first contact structure from the back side of the first die and the first pad structure is conductively coupled with the first semiconductor structure. An end of the first contact structure protrudes into the first semiconductor structure without connecting to the first pad structure. The first die and a second die can be bonded face-to-face.