Semiconductor Bonding Pad Passivation Opening Diameter
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Solution Overview
Problem
In semiconductor devices, test pads intended not to be wire bonded often get mistakenly wire bonded due to errors, making it difficult to determine the reliability of wire bonding as the resistances of both bonding and test pads are measured, leading to incorrect identification of the bonding site.
Innovation Solution
The semiconductor device incorporates a passivation layer with distinct opening portions for bonding and test pads, where the opening portion for the bonding pad has a diameter greater than the bonding wire tip, and the opening portion for the test pad has a diameter less than the bonding wire tip, preventing accidental wire bonding of the test pads by ensuring the bonding wire only contacts the bonding pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If test pads are made accessible like bonding pads, then probe testing can be performed, but wire bonding errors occur on test pads
Solution Approach 1:
The passivation layer is selectively removed to create opening portions with different diameters: larger openings over bonding pads to accommodate bonding wire tips, and smaller openings over test pads to allow probe access but prevent wire bonding. This local differentiation in opening size enables the pad area to serve multiple functions (testing and bonding) while preventing erroneous wire bonding on test pads.
2Reliability
If all pads are made accessible for wire bonding, then bonding reliability can be measured, but test pads cannot be distinguished from bonding pads
Solution Approach 1:
Different opening diameters are created in the passivation layer to locally distinguish bonding pads from test pads. The larger opening portions over bonding pads accommodate bonding wire tips for reliable bonding and subsequent resistance measurement, while smaller opening portions over test pads allow probe testing but prevent wire bonding due to insufficient exposure of the pad surface.
Data Source
AI summary
Provided is a semiconductor device that may prevent a test pad planned not to be wire bonded from being wire bonded. The semiconductor device may include a bonding pad planned to be wire bonded and a test pad planned not to be wire bonded, and a passivation layer including a first opening portion exposing part of the bonding pad and a second opening portion exposing part of the test pad, wherein the diameter of the first opening portion is greater than the diameter of a tip of a bonding wire, and the diameter of the second opening portion is less than the diameter of the tip of the bonding wire.