Packaging Substrate Electroplating Line Extraction for Signal Integrity
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Solution Overview
Problem
Conventional semiconductor packaging substrates face issues with cross-talk due to electroplating lines, leading to signal distortion and high fabrication costs, while also struggling with miniaturization and circuit layout flexibility.
Innovation Solution
A semiconductor package and packaging substrate with a conductive layer connecting all conductive traces, allowing only one electroplating line to form a surface treatment layer on wire bonding pads, and a recess to prevent adhesive overflow, reducing the number of electroplating lines and increasing circuit layout space and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple electroplating lines are used to form surface treatment layers on wire bonding pads, then electrical bonding forces are improved and oxidation is prevented, but cross-talk occurs and signal transmission is adversely affected
Solution Approach 1:
The patent extracts and removes the harmful electroplating lines from the substrate after the electroplating process is completed. Only the necessary surface treatment layer remains on the wire bonding pads, while the harmful lines that cause cross-talk are taken out, resolving the contradiction between achieving reliable bonding and avoiding signal interference
Solution Approach 2:
The electroplating lines are temporarily introduced before the electroplating process to enable current flow and surface treatment formation, then removed afterward. This preliminary action allows the surface treatment to be formed reliably while eliminating the source of cross-talk in the final product
2Ease of manufacture
If electroplating lines are extended to edges of the substrate for electroplating process, then surface treatment layer can be formed on wire bonding pads, but the lines remain on the substrate and cause signal distortion
Solution Approach 1:
The harmful electroplating lines are extracted and removed from the substrate after serving their manufacturing purpose. This extraction eliminates the source of signal distortion while the surface treatment layer remains on the wire bonding pads, resolving the contradiction between ease of manufacture and signal transmission quality
Solution Approach 2:
The electroplating lines are discarded after the electroplating process is complete, but the beneficial surface treatment layer is recovered and retained on the wire bonding pads. This approach allows the manufacturing process to be simple while the final product maintains high signal transmission quality
3Area of stationary object
If wire bonding pads are positioned close to die attach area for compact layout, then miniaturization is achieved, but adhesive overflow during chip mounting pollutes the wire bonding pads
Solution Approach 1:
A protective layer is formed over the wire bonding pads before the chip mounting process. This protective cushioning prevents adhesive overflow from polluting the pads during bonding, allowing compact layout while maintaining pad cleanliness and reliability
Solution Approach 2:
The protective layer acts as an intermediary between the adhesive and the wire bonding pads. It prevents direct contact between the adhesive and pads, enabling close positioning for miniaturization while protecting the pads from contamination
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
This solution effectively prevents cross-talk, ensures reliable electrical connections, reduces fabrication costs, and meets miniaturization requirements by minimizing the number of electroplating lines and eliminating the need for increased wire lengths.
Implementation Method 1
an electroplating process is performed such that current flows through the electroplating buses as well as the electroplating lines 111 to thereby form a surface treatment layer 14 on the wire bonding pads 110
Data Source
AI summary
A packaging substrate and a semiconductor package using the packaging substrate are provided. The packaging substrate includes: a substrate body having a die attach area, a circuit layer formed around the die attach area and having a plurality of conductive traces each having a wire bonding pad, and a surface treatment layer formed on the wire bonding pads. Therein, only one of the conductive traces is connected to an electroplating line so as to prevent cross-talk that otherwise occurs between conductive traces due to too many electroplating lines in the prior art.