Wafer Seal Ring Structure for Hermetic Bonding
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Solution Overview
Problem
In semiconductor manufacturing, previous techniques for creating a seal between wafers resulted in irregularly shaped singular seal rings, exposing test pads and die bonding pads to chemicals or processing residue, which could corrode or damage them, affecting production yield.
Innovation Solution
The implementation of dual ring die protection using both die seal rings and wafer seal rings, with the wafer seal rings providing protection for die bonding pads, test pads, and other components by forming a uniform, circular or polygonal shape around the dies, utilizing eutectic or fusion bonding processes with materials like AlCu, AlGe, or low-melting point metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If previous techniques for creating a seal between wafers are used, then a seal structure is formed, but the seal rings are irregularly shaped and expose test pads and die bonding pads to chemicals or processing residue
Solution Approach 1:
The invention divides the seal structure into two distinct components: die seal rings formed around each individual die, and wafer seal rings formed around the entire wafer perimeter. This segmentation allows each seal type to perform its specific function optimally - die seal rings protect individual dies and their pads, while wafer seal rings provide overall wafer sealing. The segmented approach resolves the contradiction by creating regular-shaped seals that properly protect sensitive areas.
Solution Approach 2:
The invention transitions from a single-plane seal concept to a multi-dimensional seal system. Die seal rings operate at the die level (first dimension), while wafer seal rings operate at the wafer level (second dimension). This dimensional hierarchy enables comprehensive protection of test pads and bonding pads through properly shaped seal structures that conform to the regular geometry of dies and wafers.
2Reliability
If previous seal techniques are used, then a seal is formed between wafers, but test pads and die bonding pads are exposed to chemicals or processing residue causing corrosion or damage
Solution Approach 1:
The die seal rings and wafer seal rings are formed in advance of subsequent processing steps to create a protective barrier. This preliminary sealing action prevents chemicals and processing residue from reaching and damaging test pads and bonding pads during later manufacturing operations. The seals are positioned and formed before the harmful processing steps occur, thereby preemptively protecting the sensitive areas.
Solution Approach 2:
The seal structures serve as a protective cushion or barrier that is established beforehand to shield test pads and bonding pads from chemical exposure. This prior cushioning effect absorbs or deflects the harmful impact of chemicals and processing residue, preventing direct contact with sensitive areas and thereby preventing corrosion or damage.
3Reliability
If dual ring die protection is implemented, then test pads, die seal rings, and bonding pads are protected from moisture and chemicals, but the device complexity increases
Solution Approach 1:
The die seal rings and wafer seal rings serve multiple functions simultaneously: they provide hermetic sealing to protect against moisture and chemicals, define processing boundaries, protect sensitive areas (test pads, bonding pads, die seal rings), and serve as structural elements during bonding and subsequent processing. This multi-functionality justifies the increased structural complexity by delivering comprehensive protection and process control in a single integrated seal system.
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 provides a hermetic seal that protects the test pads, die seal rings, and bonding pads from moisture, chemicals, and residue during subsequent processing steps, enhancing the production yield by preventing corrosion and damage.
Implementation Method 1
The solution provides a hermetic seal that protects the test pads, die seal rings, and bonding pads from moisture, chemicals, and residue during subsequent processing steps
Implementation Method 2
utilizing eutectic or fusion bonding processes with materials like AlCu, AlGe, or low-melting point metals
Implementation Method 3
utilizing eutectic or fusion bonding processes with materials like AlCu, AlGe, or low-melting point metals
Data Source
AI summary
A wafer seal ring may be formed on a first and/or a second wafer. One or both of the first and/or second wafers may have one or more dies formed thereon. The wafer seal ring may be formed to surround the dies of a corresponding wafer. One or more die seal rings may be formed around the one or more dies. The wafer seal ring may be formed to a height that may be approximately equal to a height of one or more die seal rings formed on the first and/or second wafer. The wafer seal ring may be formed to provide for eutectic or fusion bonding processes. The first and second wafers may be bonded together to form a seal ring structure between the first and second wafers. The seal ring structure may provide a hermetic seal between the first and second wafers.