IC Module Via-Pad Layout to Prevent Bonding Wire Disconnection
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Solution Overview
Problem
The existing IC modules are prone to bonding wire disconnection due to external stress, as the metal plated pad on the rear substrate can overlap slits on the front surface, and the bonding wire may step over regions without a conductor pattern, leading to increased force on the wire.
Innovation Solution
The IC module design includes a substrate with a metal surface on one side and an IC chip on the other, featuring terminals for contact and contactless communication, with a via connecting the terminals and a metal connection pad positioned opposite the IC chip, and a bonding wire connecting the pad to the IC chip, ensuring the wire does not overlap slits and is kept short and loosened to reduce external force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the metal plated pad is disposed in a position overlapping the slit on the front surface, then the wiring layout is simplified, but external stress causes large force to act on the bonding wire leading to disconnection
Solution Approach 1:
The patent resolves the contradiction by transitioning the bonding wire routing from a two-dimensional path on the substrate surface to a three-dimensional path that extends in the thickness direction of the substrate. The wire is routed through the substrate thickness to connect the front surface terminal to the rear surface pad, bypassing the problematic slit region and reducing stress concentration.
2Reliability
If the bonding wire is made longer to reach the metal plated pad, then the pad can be positioned for optimal electrical connection, but the wire becomes more susceptible to external force and disconnection
Solution Approach 1:
The patent reduces bonding wire length and improves mechanical strength by routing the wire through the substrate thickness dimension rather than across the surface. This vertical routing through the via hole creates a shorter, more direct path that is less susceptible to external forces applied during card bending or insertion.
3Ease of manufacture
If the bonding wire is disposed to step over the region without conductor pattern, then the metal plated pad can be positioned opposite the IC chip, but external stress increases force on the wire
Solution Approach 1:
The patent eliminates the need for the bonding wire to step over regions without conductor patterns by routing the wire vertically through the substrate thickness. The wire connects the front surface terminal directly to the rear surface pad through the via hole, avoiding exposure to external stresses from card bending or insertion that would affect wires routed across the substrate surface.
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 configuration effectively suppresses external force on the bonding wire and prevents disconnection, enhancing the durability of the IC module under stress conditions such as bending.
Implementation Method 1
the substrate includes a via that is formed on an inner surface of a through hole penetrating from the first surface to the second surface and is connected to the first terminal
Implementation Method 2
a bonding wire that connects between a connection end, of the connection pad, positioned closer to the IC chip than to the via and a connection terminal of the IC chip
Data Source
AI summary
An IC module includes: a substrate that has a first surface and a second surface opposite the first surface and a metal surface at least on the first surface; and an IC chip with both a contact communication function and a contactless communication function, in which a plurality of terminals constituted by the metal surface is formed on the first surface of the substrate, the plurality of terminals containing a first terminal used for contact communication and a second terminal other than the first terminal, and the substrate includes a via formed on an inner surface of a through hole penetrating from the first surface to the second surface and is connected to the first terminal, a metal connection pad extending from the via to a portion, on the second surface, positioned opposite the second terminal overlapping the IC chip when seen from a thickness direction of the substrate.