Metallic Edge-Reinforcement Ring for Semiconductor Chip Fracture Toughness
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Solution Overview
Problem
Microelectronic elements, such as semiconductor chips, often develop cracks and microdefects during the dicing process due to stress at the edge surfaces, leading to potential failures during packaging, testing, or operation, despite existing methods like internal seal rings and various dicing techniques.
Innovation Solution
A continuous monolithic metallic edge-reinforcement ring is applied to the semiconductor chip, extending onto its edge surfaces and potentially onto the front and rear surfaces, made from materials like aluminum, tungsten, nickel, or chromium, to reinforce the edges and minimize cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical blade dicing or other separation methods are used to free individual chips from the wafer, then the chips can be packaged and tested, but microdefects and cracks occur at the edge surfaces of the chips
Solution Approach 1:
A stress relief groove is formed at the edge surface of the chip before dicing operations. This preliminary structural modification allows stress to be concentrated in a controlled location, preventing random crack formation during subsequent mechanical blade dicing or separation processes.
Solution Approach 2:
The stress relief groove acts as an intermediary structure that mediates between the dicing blade and the chip edge. It provides a predetermined path for stress release, preventing direct transmission of cutting forces to the chip's functional areas and eliminating microdefects.
2Strength
If internal seal rings are used to prevent cracking at exterior edges, then some crack resistance is improved, but the solution is insufficient to prevent microdefects during dicing and handling
Solution Approach 1:
Instead of using a generic internal seal ring throughout, the invention applies a stress relief groove specifically at the edge surface where dicing stresses concentrate. This localized structural modification addresses the specific problem area with targeted geometry that channels stress away from vulnerable regions.
Solution Approach 2:
The invention changes the geometric parameters of the chip edge by introducing a groove with specific depth and width dimensions. This parameter modification creates a stress concentration zone that controls where cracks may form, preventing them from propagating into the chip's functional areas during dicing and handling.
Data Source
AI summary
A method of making an edge-reinforced microelectronic element is disclosed. The steps include mechanically cutting along dicing lanes of a substrate at least partially through a thickness thereof to form a plurality of edge surfaces extending away from a front surface thereof and forming a continuous monolithic metallic edge-reinforcement ring that covers each of the plurality of edge surfaces and extends onto the front surface. The front surface may have a plurality of contacts thereat and the substrate may embody a plurality of microelectronic elements.