Protective Material for Semiconductor Wafer Singulation
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Solution Overview
Problem
The existing semiconductor manufacturing process for die-to-wafer packages faces challenges in singulating individual die without causing damage, such as chipping or cracking, due to the lack of support between mounted semiconductor die, leading to defects and failures.
Innovation Solution
A method is introduced where a protective material is formed over the semiconductor die and wafer surface, allowing for singulation without damaging the die, and subsequently mounting the die-to-wafer packages to a substrate with an encapsulant deposited over the package and substrate for further protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If semiconductor die are mounted on a wafer surface with air space between them, then device integration is achieved, but the unsupported wafer portions become susceptible to damage during singulation
Solution Approach 1:
A protective material layer is introduced as an intermediary between the mounted semiconductor die and the wafer surface. This protective material fills the air spaces and provides mechanical support to the wafer during singulation, preventing chipping and cracking while allowing the die-to-wafer package structure to function
Solution Approach 2:
The protective material is applied before the singulation process to cushion and protect the wafer structure. This pre-protection prevents damage that would otherwise occur during the mechanical cutting process, allowing safe singulation of the die-to-wafer packages
2Productivity
If singulation is performed on unsupported wafer portions, then individual packages are produced, but chipping and cracking occur on the die
Solution Approach 1:
The protective material serves as a mediator during the singulation process, supporting the wafer structure where die are mounted and preventing the saw blade from causing chipping or cracking on the die edges, thereby enabling precise singulation
Solution Approach 2:
The protective material is applied in advance before singulation to prepare the wafer for the cutting process. This preliminary protection ensures that when singulation occurs, the die edges remain intact and free from damage
3Ease of operation
If air space exists between mounted die, then mounting flexibility is maintained, but contaminant accumulation occurs on the wafer back surface
Solution Approach 1:
The protective material is removed after singulation and before final packaging. This extraction eliminates the source of contaminant accumulation while having already served its protective function during the critical singulation process
Solution Approach 2:
The protective material acts as a temporary intermediary that prevents contaminants from reaching the wafer back surface during singulation. After serving this protective function, it is removed to prevent it from becoming a source of contamination itself
Data Source
AI summary
A semiconductor wafer contains first semiconductor die. TSVs are formed through the semiconductor wafer. Second semiconductor die are mounted to a first surface of the semiconductor wafer. A first tape is applied to on a second surface of the semiconductor wafer. A protective material is formed over the second die and first surface of the wafer. The protective material can be encapsulant or polyvinyl alcohol and water. The wafer is singulated between the second die into individual die-to-wafer packages each containing the second die stacked on the first die. The protective material protects the wafer during singulation. The die-to-wafer package can be mounted to a substrate. A build-up interconnect structure can be formed over the die-to-wafer package. The protective material can be removed. Underfill material can be deposited beneath the first and second die. An encapsulant is deposited over the die-to-wafer package.