Backside Pad Structure for Face-to-Face Bonded Memory Dies
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Solution Overview
Problem
Existing semiconductor memory devices face challenges in forming pad structures on the back side of dies without the need for through-silicon contacts, which complicates the fabrication process and may lead to inefficiencies in connecting input/output circuits.
Innovation Solution
The semiconductor device involves bonding two dies face-to-face, with a contact structure protruding from an insulating portion to form pad structures on the back side of one die, allowing for direct conductive coupling without the need for through-silicon contacts, using different metal materials like tungsten and aluminum, and forming connection structures that are conductively connected to the semiconductor portion without contact holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through-silicon contacts are used to form pad structures on the back side of dies, then connectivity for input/output circuits is achieved, but the fabrication process becomes complicated
Solution Approach 1:
The contact structure is formed protruding from the insulating portion before die bonding, allowing the pad structure to be formed directly on the back side after bonding without requiring through-silicon contacts. This preliminary formation of the contact structure eliminates the need for complex post-bonding through-silicon contact fabrication while maintaining reliable connectivity.
Solution Approach 2:
The device is divided into two separate dies bonded face-to-face, with the contact structure formed in the insulating portion of the first die and the pad structure formed on the back side. This segmentation allows independent optimization of each die and eliminates the need for through-silicon contacts, simplifying the overall fabrication process while maintaining connectivity.
2Ease of manufacture
If through-silicon contacts are used to form pad structures, then pad structures can be formed on the back side, but fabrication limitations are compromised
Solution Approach 1:
The contact structure is formed protruding from the insulating portion before die bonding, which allows the pad structure to be formed directly on the back side after bonding without requiring through-silicon contacts. This approach maintains manufacturing precision by avoiding the complex fabrication steps of through-silicon contacts while enabling pad structure formation on the back side.
3Device complexity
If contact structures are formed in insulating portions with protruding ends, then pad structures can be formed directly on the back side without through-silicon contacts, but the contact structure design becomes more complex
Solution Approach 1:
The contact structure is merged with the insulating portion, forming a protruding contact structure that extends from the insulating material. This integration allows the contact structure to be formed as part of the insulating portion fabrication process, simplifying the overall design while enabling direct pad structure formation on the back side without through-silicon contacts.
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 simplifies the fabrication of pad structures, enhances connectivity for input/output circuits, and optimizes the performance of memory cell arrays and periphery circuitry without compromising fabrication limitations, enabling efficient semiconductor memory device construction.
Implementation Method 1
bonding a first die and a second die face-to-face
Implementation Method 2
the first pad structure is conductively coupled with the contact structure
Implementation Method 3
the contact structure includes at least a first metal material that is different from a second metal material in the first pad structure. In an example, the first metal material includes tungsten and the second metal material includes aluminum
Data Source
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AI summary
A semiconductor device (100) includes a first die (102) and a second die (101) bonded face-to-face. The first die (102) includes first transistors formed on a face side of the first die (102) in a semiconductor portion (105) and at least a contact structure (170) disposed in an insulating portion (106) outside the semiconductor portion (105). The second die (101) includes a substrate (104) and second transistors formed on a face side of the second die (101). Further, the semiconductor device (100) includes a first pad structure (122, 123) disposed on a back side of the first die (102) and the first pad structure (122, 123) is conductively coupled with the contact structure (170). An end of the contact structure (170) protrudes from the insulating portion (106) into the first pad structure (122, 123). Further, in some embodiments, the semiconductor device (100) includes a connection structure (121) disposed on the back side of the first die (102) and conductively connected with the semiconductor portion (105).