Embedded UBM Layer in Passivation for Semiconductor Reliability
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Solution Overview
Problem
The existing methods for forming an under bump metallurgy (UBM) layer in semiconductor devices are complex and prone to warpage, requiring additional carriers and dedicated lines, which increases the risk of process quality issues and yield reduction due to the need for high cleanliness processes.
Innovation Solution
A semiconductor device with a UBM layer embedded in a passivation layer, where UBM pads have recess portions and UBM vias connect the redistribution layer, allowing for a simplified process and improved reliability by forming the UBM layer before the redistribution layer, eliminating the need for additional carriers and dedicated lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UBM layer is formed after the package process using the related art method, then the connection reliability can be improved, but the process complexity increases and additional carriers are required
Solution Approach 1:
The UBM layer is formed in advance on the carrier before the package process, rather than after. This preliminary formation of the UBM layer eliminates the need for post-package processing and removes the requirement for additional carriers, thereby reducing process complexity while maintaining connection reliability
Solution Approach 2:
The UBM layer formation process is extracted from the post-package process and integrated into the pre-package carrier process. This separation allows the UBM layer to be formed independently on the carrier before package assembly, simplifying the overall manufacturing flow
2Reliability
If the UBM layer is formed after the package process, then connection reliability can be improved, but the manufacturing cost increases due to dedicated lines
Solution Approach 1:
The UBM layer formation process is merged with the existing carrier process that is already in place for package assembly. By combining these processes, the need for separate dedicated lines is eliminated, reducing manufacturing infrastructure costs while ensuring reliable connections
3Reliability
If products pass through package line with low cleanliness and then exposing/plating processes with high cleanliness, then the UBM layer can be formed, but the risk of process quality issues and yield reduction increases
Solution Approach 1:
The UBM layer is formed preliminarily on the carrier before the package process, which means the high cleanliness requiring processes (exposing and plating) are completed before the package line. This eliminates the risk of contamination between low and high cleanliness zones, improving both process quality and yield
Data Source
AI summary
A semiconductor device includes a semiconductor chip having an active surface having connection pads disposed thereon; an encapsulant encapsulating at least portions of the semiconductor chip, a connection member disposed on the active surface of the semiconductor chip and including a redistribution layer electrically connected to the connection pads, a passivation layer disposed on the connection member, and an under bump metallurgy (UBM) layer embedded in the passivation layer and electrically connected to the redistribution layer of the connection member. The UBM layer includes a UBM pad embedded in the passivation layer and having a recess portion, and a UBM via penetrating through a portion of the passivation layer and electrically connecting the redistribution layer of the connection member and the UBM pad to each other.