Inclined Seal Ring Structure for Bubble-Free Semiconductor Assembly
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Solution Overview
Problem
Conventional semiconductor assembly processes face issues with photoresist bubbles leading to micro-cracking and solder residue during the bump plating process, necessitating an improved seal ring structure to prevent defects.
Innovation Solution
The proposed solution involves forming a seal ring with an inclined side surface and varying the distance between the metal line and the semiconductor assembly's side surface, as well as exposing portions of the metal line to air, to enhance the seal ring's structure and prevent bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional seal ring structure is used, then the manufacturing process is simple, but photoresist bubbles form causing micro-cracking and solder residue
Solution Approach 1:
The seal ring structure employs an asymmetric design where the distance between the metal line and the semiconductor assembly side surface varies along the perimeter. Specifically, the distance is smaller at corners and larger at mid-sections, creating an asymmetric profile that prevents photoresist bubble accumulation while maintaining manufacturing feasibility
Solution Approach 2:
The invention introduces a new dimensional parameter - the varying distance from the metal line to the semiconductor assembly side surface - to control bubble formation. By manipulating this spatial dimension asymmetrically around the seal ring perimeter, the design prevents micro-cracking without significantly complicating the manufacturing process
2Reliability
If the distance between metal line and semiconductor assembly side surface is uniform, then the manufacturing process is easier, but bubbles form after photoresist coating
Solution Approach 1:
The seal ring structure employs an asymmetric design where the distance between the metal line and the semiconductor assembly side surface varies along the perimeter. Specifically, the distance is smaller at corners and larger at mid-sections, creating an asymmetric profile that prevents photoresist bubble accumulation while maintaining manufacturing feasibility
Solution Approach 2:
Different sections of the seal ring are designed with different distance characteristics - corners have smaller distances while mid-sections have larger distances. This local variation in geometric quality prevents bubble formation at critical locations without requiring uniform high-precision control throughout the entire structure
3Manufacturing precision
If photoresist bubbles are present, then the photoresist coating process is complete, but micro-cracking occurs in the insulation layer
Solution Approach 1:
The asymmetric seal ring geometry is designed in advance to counteract the harmful effects of photoresist bubbles before they can cause damage. By creating a structure where bubbles are prevented from forming or are redirected to non-critical areas, the design proactively prevents micro-cracking in the insulation layer before the plating process begins
Data Source
AI summary
A semiconductor assembly includes a semiconductor device and a seal ring. The seal ring is disposed adjacent to the semiconductor device. The seal ring includes a first side surface inclined from a top surface of the seal ring toward a bottom surface of the seal ring, wherein a lateral width of the bottom surface of the seal ring is larger than a lateral width of the top surface of the seal ring; and a first metal line disposed in the seal ring and comprising a second side surface adjacent to the first side surface of the seal ring. A maximum distance between the second side surface of the first metal line and the first side surface of the seal ring is in a range of 5 μm to 30 μm.